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Explains the causes, symptoms, diagnosis, and surgical treatment of traumatic canalicular laceration. Details the characteristics by injury mechanism such as dog bites and assault, repair techniques including lacrimal tube intubation, and postoperative management.

A chronic infection of the lacrimal canaliculus, most commonly caused by Actinomyces israelii. It forms concretions (sulfur granules) within the canaliculus and presents as unilateral refractory conjunctivitis. First-line treatment is canaliculotomy and curettage under local anesthesia, followed by topical new quinolone and systemic penicillin.

Canaloplasty is a non-penetrating glaucoma surgery that dilates Schlemm's canal to restore physiological aqueous outflow. In addition to the conventional ab externo approach, modified techniques such as ab interno canaloplasty (ABiC) and the OMNI system have been developed.

An autoimmune retinal degenerative disease associated with malignant tumors. A type of paraneoplastic syndrome in which autoantibodies due to cross-reactivity between tumor antigens and retinal proteins damage photoreceptor cells, causing rapidly progressive vision loss and visual field constriction.

This article explains the intraocular pressure-lowering effects of cannabinoids and their potential application in glaucoma treatment, covering the endocannabinoid system, receptors, effects by route of administration, neuroprotective effects, side effect profile, and the opinions of major ophthalmology societies.

The most common benign orbital tumor in childhood. It grows within the first year of life and then spontaneously regresses over several years. If there is a risk of amblyopia, treatment with beta-blockers is the first-line therapy.

CAPOS syndrome is a rare neurological disease caused by mutations in the ATP1A3 gene. Its five main signs are cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss. It is characterized by paroxysmal neurological symptoms triggered by fever, as well as progressive vision loss and hearing loss.

A group of devices used to maintain capsular stability during cataract surgery with zonular weakness or dehiscence. Includes capsular tension ring (CTR), modified CTR, capsular tension segment (CTS), and capsule support hooks.

Carotid-cavernous fistula (CCF) is an abnormal vascular connection between the internal carotid artery or external carotid artery and the cavernous sinus. The triad includes pulsatile exophthalmos, conjunctival chemosis, and vascular bruit. Endovascular treatment is the first-line therapy.

Carotidynia (TIPIC syndrome) is a self-limiting disease characterized by unilateral neck pain due to perivascular inflammation at the carotid bifurcation. This article explains diagnostic criteria, imaging findings, treatment, and ophthalmic signs.

A disease in which the lens becomes cloudy, causing decreased vision. Aging is the most common cause, and the prevalence reaches 100% in people aged 80 and older. Phacoemulsification and intraocular lens implantation are the only curative treatments.

Overview of surgery for cataract that progresses after vitrectomy, and combined cataract and vitrectomy surgery (phacovitrectomy). Preoperative, intraoperative, and postoperative points to note are explained.

This article explains preoperative planning, IOL power calculation, surgical techniques, and postoperative management for cataract surgery in patients with keratoconus (a progressive ectatic corneal disease). The main challenges are difficulty in IOL power calculation and postoperative refractive error.

Positioning management for cataract surgery in patients who cannot assume the supine position (lying flat on the back). Explains three options for patients with ankylosing spondylitis, orthopnea, kyphosis, etc.

Explanation of educational methods for acquiring cataract surgery (phacoemulsification). Shows an overview of modern surgical education including VR simulators, wet labs, and competency assessment.

An innovative cataract surgery technique that prevents posterior capsule opacification by fitting both the anterior and posterior capsule edges into the groove of the intraocular lens. It is applicable to both adults and children.

A disease caused by caterpillar or insect setae penetrating ocular tissues and inducing granulomatous inflammation. This article explains the classification (Cadera Type I–V), treatment, and multimodal imaging diagnosis.

A syndrome presenting with ophthalmoplegia, facial sensory disturbance, and Horner syndrome due to lesions of the cavernous sinus. The most common cause is tumor, but vascular, inflammatory, and infectious lesions are also important differential diagnoses.

An inherited macular dystrophy that causes well-demarcated chorioretinal atrophy in the macula. PRPH2 gene mutations are the main cause, and progression leads to severe central vision loss.

A rare benign neuronal tumor (WHO grade II) that commonly occurs in the lateral ventricle. It predominantly affects young adults aged 20-40 and presents with symptoms of increased intracranial pressure due to obstructive hydrocephalus. Total resection is the standard treatment, and the prognosis is favorable.

An ophthalmic emergency in which the central retinal artery suddenly occludes, causing rapid and severe vision loss. Irreversible changes begin approximately 100 minutes after occlusion, and it shares the same risk factors as stroke.

A vascular disease in which the central retinal vein becomes occluded within the optic nerve, causing hemorrhage and edema throughout the retina. It is the second most common retinal vascular disease after diabetic retinopathy, and macular edema and neovascular glaucoma determine visual prognosis.

A disease characterized by serous retinal detachment in the macula, presenting with metamorphopsia, micropsia, and central scotoma. It predominantly affects men in their 30s to 40s, with stress and steroids being major risk factors.

A rare visual perseveration phenomenon in which multiple images are perceived from a single visual stimulus due to brain injury. Associated with lesions in the occipital lobe or posterior parietal cortex.

Cerebral venous and dural sinus thrombosis (CVST) is a blood clot in the cerebral venous drainage system, causing papilledema and visual impairment due to increased intracranial pressure. It is a rare disease accounting for 0.5–3% of all strokes.

This article explains the symptoms, diagnosis, and treatment of cerebral venous sinus thrombosis (CVST) caused by coagulopathy due to snakebite.

Visual impairment in children due to damage to the visual pathways beyond the lateral geniculate nucleus. It is the leading cause of visual impairment in children in developed countries, with hypoxic-ischemic encephalopathy being the most common etiology. Multidisciplinary rehabilitation is important.

An extremely rare autosomal recessive disorder caused by defects in the nucleotide excision repair pathway. It presents with microcephaly, congenital cataracts, microphthalmia, and multiple joint contractures, and the prognosis is very poor.

A rare autosomal recessive lipid storage disease caused by CYP27A1 gene mutation leading to sterol 27-hydroxylase deficiency, impairing bile acid synthesis and resulting in accumulation of cholestanol in the brain, tendons, and lens.

Explains the visual impairment grading criteria for the physical disability certificate, methods for assessing visual acuity and visual field, grade determination by total index, application process, and welfare services after issuance.

This article explains the mechanism of action, efficacy, safety, and neuro-ophthalmological significance of CGRP-targeted monoclonal antibodies (erenumab, fremanezumab, galcanezumab, eptinezumab) for migraine prevention.

Comprehensive explanation of chalazion (non-infectious chronic granulomatous inflammation of the meibomian gland): definition, symptoms, classification, diagnosis (differentiation from sebaceous gland carcinoma), treatment (warm compresses, steroid injection, transconjunctival/transcutaneous excision), pathophysiology, and prognosis.

Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral nerve disorder, characterized by distal muscle atrophy, weakness, and sensory impairment. Over 80 causative genes have been identified, and ophthalmologically, it may be associated with optic atrophy and retinal degeneration.

A multiple congenital anomaly syndrome characterized by coloboma, heart defects, choanal atresia, growth retardation, genital abnormalities, and ear anomalies due to CHD7 gene mutation. Multidisciplinary management is required, and ophthalmologically, attention to the risk of retinal detachment associated with coloboma is important.

Complex visual hallucinations occurring in people with visual impairment, not associated with mental illness. It can be caused by various conditions such as eye disease, brain disease, or trauma, and cognitive function is preserved.

Cheiro-Oral Syndrome is a rare neurological disorder characterized by sensory disturbances around the mouth and in the hands and fingers. It is known as a subtype of thalamic stroke syndrome and may be accompanied by oculomotor disturbances and visual field defects.

This article explains the definition, clinical features, severity assessment, and treatment from eye irrigation to surgery for ocular injuries caused by acidic chemicals. It clarifies the differences in pathophysiology from alkali injuries.

This article explains the definition of ocular injury caused by alkaline chemicals, severity assessment using the Kinoshida classification, and treatment from emergency irrigation to ocular surface reconstruction.

Chemical injury of the conjunctiva and cornea is an ophthalmic emergency requiring immediate irrigation. Alkali agents penetrate deeply and often cause severe damage. Severity is assessed using the Kinoshida classification or Roper-Hall classification, and management is staged from conservative treatment in the acute phase to surgical ocular surface reconstruction in the cicatricial phase.

A fundus finding in which the red color of the fovea stands out against a whitened retina. It appears in many diseases including central retinal artery occlusion and lysosomal storage disorders, and is an important clinical sign requiring urgent systemic evaluation.

Explains the causes, diagnosis, and treatment of visual field defects (bitemporal hemianopia) due to compressive, inflammatory, or traumatic lesions of the optic chiasm. Comprehensively covers pituitary adenoma, craniopharyngioma, chiasmal optic neuritis, and traumatic chiasmal syndrome.

Explains symptoms, risk factors, screening tests, and treatment of drug-induced toxic retinopathy caused by chloroquine (CQ) and hydroxychloroquine (HCQ, Plaquenil®). Early detection and preventive management of bull's eye maculopathy.

A closed-eye injury caused by high-velocity projectile impact, resulting in full-thickness rupture of the choroid, Bruch's membrane, and retina with exposure of the sclera. Observation is the mainstay, but surgery is required if retinal detachment occurs.

This article explains the diagnosis, treatment, and prognosis of posterior uveal melanoma arising from the choroid and ciliary body, which is the most common primary intraocular malignant tumor in adults.

A condition in which the choroid, Bruch's membrane, and RPE develop wavy undulations. It can be caused by various factors such as ocular hypotony, orbital tumors, increased intracranial pressure, high hyperopia, and posterior scleritis, and may lead to metamorphopsia and decreased visual acuity.

Inflammatory choroidal neovascularization (I-CNV) is a serious complication of chorioretinitis and posterior uveitis, and is the third most common cause of CNV after age-related macular degeneration and pathologic myopia. This article explains treatment strategies combining control of underlying inflammation with intravitreal anti-VEGF injections, multimodal imaging diagnosis using OCTA and ICGA, and characteristic findings such as the pitchfork sign.

Explains OCT angiography (OCTA) findings of choroidal neovascularization (CNV/MNV). Covers OCTA features of type 1, type 2, and type 3 CNV and PCV, comparison with conventional fluorescein angiography, and notes on artifacts.

This article explains the evaluation of malignant transformation risk factors (TFSOM-UHHD) and follow-up strategies for benign pigmented lesions derived from choroidal melanocytes.

A rare benign tumor with ectopic bone formation in the choroid. It commonly occurs in the posterior pole and is slightly more frequent in young women. High CT attenuation equivalent to bone is key for definitive diagnosis. This article also discusses treatment including management of choroidal neovascularization.

A rare benign tumor in which mature bone forms in the choroid. It predominantly affects women in their 10s to 30s and can cause choroidal neovascularization leading to vision loss.

A disease in which blunt trauma to the eye causes rupture of Bruch's membrane, the choriocapillaris, and the retinal pigment epithelium. Immediately after injury, it is hidden by hemorrhage, but after absorption, it is observed as a crescent-shaped white line. Attention must be paid to the development of choroidal neovascularization.

An X-linked recessive chorioretinal dystrophy caused by mutations in the CHM gene. It leads to progressive degeneration of the retinal pigment epithelium, photoreceptors, and choriocapillaris, progressing from night blindness to peripheral visual field loss and eventually severe visual impairment. Gene therapy clinical trials are ongoing.

Chromatopsia is a condition in which the visual field appears tinted with a specific color. The main causes are medications (e.g., digitalis, PDE5 inhibitors), retinal diseases, and brain diseases. In most cases, removal of the cause leads to recovery.

A technique in vitreous surgery that visualizes semitransparent tissues such as the internal limiting membrane, vitreous, and epiretinal membrane using vital dyes. Brilliant Blue G, triamcinolone acetonide, and indocyanine green are used.

A disease in which the extraocular muscles are selectively impaired due to mitochondrial dysfunction, leading to slowly progressive bilateral ptosis and ophthalmoplegia. It is classified into isolated CPEO and CPEO-plus with systemic symptoms.

Cicatricial conjunctivitis is a group of vision-threatening diseases characterized by chronic inflammation and scarring of the conjunctiva, caused by various factors such as autoimmune diseases (ocular cicatricial pemphigoid), drug toxicity, infections, and chemical trauma. Early diagnosis and treatment according to the underlying disease determine the prognosis.

This article explains the diagnosis, differential diagnosis including transillumination, and treatment strategy for primary ciliary body malignant melanoma, which accounts for approximately 7% of uveal melanomas.

A localized (solitary) benign vascular tumor of the choroid. It appears as an orange-red elevated lesion in middle-aged and older adults, and when it causes vision loss due to serous retinal detachment, PDT or laser treatment is indicated.

A refractive surgery that removes the clear lens without cataract and inserts an intraocular lens. Performed for high refractive errors and angle-closure glaucoma.

Idiopathic retinal vascular disease characterized by abnormal dilation and exudation of retinal capillaries. It predominantly affects young boys and progresses unilaterally.

An inborn error of intracellular vitamin B12 metabolism caused by mutations in the MMACHC gene. The early-onset type presents with macular degeneration and retinal degeneration from infancy, leading to severe visual impairment.

Cogan syndrome is a rare autoimmune disease characterized by non-syphilitic interstitial keratitis and vestibuloauditory symptoms. It predominantly affects young adults and presents with recurrent ocular inflammation and progressive hearing loss. Up to 80% of patients have systemic symptoms, and up to 15% have vasculitis.

A congenital eye disease in which tissue defects occur in various parts of the eye due to incomplete closure of the embryonic fissure. It is often accompanied by microphthalmia and causes visual impairment and complications depending on the location of the defect.

Explains the basic concepts of color vision, classification of congenital and acquired color vision deficiencies, symptoms, diagnostic methods, pathophysiology, and latest research including gene therapy.

Color vision testing is a general term for tests that determine the presence, type, and severity of color vision deficiency. This article explains the principles, procedures, and interpretation of results for screening with Ishihara color vision test plates, severity assessment with the Panel D-15 test, and detailed evaluation with the Farnsworth-Munsell 100 hue test.

This article explains the principles, indications, and clinical effects of FL-41 lenses and optical notch filters for reducing photophobia (light sensitivity). It details the melanopsin mechanism of intrinsically photosensitive retinal ganglion cells (ipRGCs) and the application of wavelength-selective blocking.

This article organizes the concepts of combined surgery for cataract and glaucoma. It clearly explains the selection axes: cataract surgery alone, combined with MIGS, combined with trabeculectomy, and combined with drainage device.

A general term for conditions in which multiple cranial nerves are simultaneously affected due to brainstem (midbrain, pons, medulla oblongata) lesions, presenting with various ocular motor disturbances, nystagmus, and pupillary abnormalities. Causes include cerebrovascular disease, demyelinating diseases, and inflammatory diseases, with characteristic symptom patterns depending on the lesion site.

Combined hamartoma of the retina and retinal pigment epithelium (CHRRPE) is a rare benign tumor made up of glial, vascular, and retinal pigment epithelial tissue in the retina and RPE, mainly occurring near the optic disc and macula in children, and causing decreased vision and strabismus.

A disease in which the outer segments of photoreceptors are damaged after blunt ocular trauma, resulting in characteristic white opacification of the retina. It often resolves spontaneously within about two weeks, but visual prognosis may be poor if the macula is affected.

A comparative explanation of the characteristics of intraocular lens (IOL) materials used in cataract surgery. Covers optical properties, biocompatibility, and complications of major materials such as hydrophobic acrylic, hydrophilic acrylic, silicone, PMMA, and collamer.

Cataract that occurs secondary to uveitis or systemic diseases (e.g., diabetes, atopic dermatitis, myotonic dystrophy). Preoperative inflammation control and perioperative management determine surgical outcomes.

This article explains the pathophysiology, diagnosis, and management of complications after radial keratotomy (RK), including diurnal fluctuation, progressive hyperopia, corneal perforation, irregular astigmatism, and infectious keratitis.

Acetazolamide is a carbonic anhydrase inhibitor used for glaucoma and idiopathic intracranial hypertension, causing various complications such as transient myopia, ciliochoroidal effusion, and metabolic acidosis.

A general term for intraoperative and postoperative complications associated with cataract surgery. Includes posterior capsule rupture, posterior capsule opacification, cystoid macular edema, endophthalmitis, intraocular lens dislocation, etc. Appropriate prevention and management directly affect visual prognosis.

Complications after cosmetic eyelid surgery (double-eyelid surgery, eyelid fat removal, etc.) are classified into early (infection, hematoma, overcorrection) and late (ptosis, incomplete eyelid closure, sunken eye). Incomplete eyelid closure carries a risk of exposure keratitis, so ophthalmic care is important. Revision surgery may include levator refixation, skin grafting, and fat injection.

Hyaluronic acid fillers and autologous fat injections around the orbit carry a risk of irreversible vision loss due to vascular occlusion. The glabella and nasal root are the most dangerous areas because of dense anastomoses between the supratrochlear artery and the ophthalmic artery. For hyaluronic acid, emergency hyaluronidase injection is available as a treatment, but there is no specific treatment for autologous fat.

This article explains the incidence, diagnosis, and treatment of intraoperative and postoperative complications in strabismus surgery. It covers prevention and management of complications from scleral perforation, oculocardiac reflex, lost muscle to anterior segment ischemia and postoperative infection.

A comprehensive explanation of eye drops used in the management of uveitis. Indicates the selection and precautions for steroids, mydriatics, and intraocular pressure-lowering drugs.

A comprehensive explanation of glaucoma eye drops by drug class. Covers prostaglandin analogs (PGAs), EP2 receptor agonists (Eybelis), beta-blockers, CAIs, alpha-2 agonists, ROCK inhibitors, and fixed combinations, including their mechanisms of action, side effects, contraindications, list of approved drugs in Japan, and treatment steps. Also provides a comprehensive description of target intraocular pressure setting and adherence improvement strategies.

Explains the types, characteristics, and selection criteria for sutures and suture needles used in ophthalmic surgery, how they are used for different procedures, and the mechanics of suturing and timing for suture removal.

Optic neuropathy caused by compression of the optic nerve by mass lesions such as tumors, aneurysms, cysts, or enlargement of extraocular muscles in thyroid eye disease. Lesions often occur at the orbital apex or optic chiasm, and the mainstay of treatment is imaging diagnosis and management of the underlying cause.

A general term for visual field defects caused by compression of the visual pathway by mass lesions such as tumors, aneurysms, or cysts. Depending on the site of compression, various patterns such as bitemporal hemianopia, homonymous hemianopia, or quadrantanopia may occur. Imaging diagnosis and removal of the causative lesion are the mainstays of treatment.

This article explains the latest research trends in the application of computational fluid dynamics (CFD) to ophthalmology, including analysis of aqueous humor dynamics, simulation of intravitreal drug distribution, evaluation of shear stress after laser iridotomy, and heat transfer models of the lens.

A group of eye, visual, and musculoskeletal symptoms caused by prolonged use of digital devices. The global prevalence is approximately 66%, rising to 74% after the COVID-19 pandemic. Abnormal blinking, accommodative disorders, and environmental factors are the main mechanisms, and preventive measures such as improving the work environment and the 20-20-20 rule are important.

Cone dystrophy is a hereditary disease in which the cone photoreceptors of the retina are progressively impaired. After the age of 20–30, patients develop decreased visual acuity, photophobia, and color vision abnormalities. ERG shows marked reduction of cone responses. Treatment mainly involves light-filtering lenses and low vision care.

An in vivo imaging diagnostic method that allows non-invasive observation of the cornea at the cellular level. It has a wide range of clinical applications, including detection of pathogens in corneal infections, differentiation of corneal dystrophies, and evaluation of corneal nerves. The HRT III-RCM is the current standard device, achieving lateral resolution of 1–2 μm and depth resolution of 4 μm.

Lens opacity that develops at birth or during infancy. It occurs in 1 in 1,000 to 10,000 births. Early surgery to prevent form deprivation amblyopia, along with long-term amblyopia treatment and refractive correction, determines visual prognosis.

Lens opacity that develops at birth or during infancy, causing form deprivation amblyopia. The timing of surgery, appropriateness of IOL implantation, and postoperative amblyopia treatment determine visual prognosis.

A condition in which color discrimination ability differs from normal due to congenital deficiency or functional abnormality of cone photopigments. Congenital red-green color vision deficiency is found in about 5% of Japanese males and shows X-linked recessive inheritance. Visual functions other than color vision are normal and do not progress.

Congenital cranial dysinnervation disorders (CCDDs) are a group of congenital, non-progressive eye movement disorders caused by abnormal development of cranial nerves. They include Duane syndrome and CFEOM, presenting with paralytic strabismus due to aberrant innervation of extraocular muscles.

Congenital cystic eye (CCE) is an extremely rare congenital ocular malformation in which a cyst forms in the orbit instead of the eyeball due to impaired invagination of the primary optic vesicle during early embryonic development. Standard treatment involves cyst removal and prosthetic eye fitting.

Explains the etiology, symptoms, clinical findings, diagnosis, differential diagnosis, treatment, and prognosis of congenital ectropion uveae (CEU). A rare disease characterized by unilateral anterior chamber dysgenesis and secondary glaucoma.

Congenital fibrosis of the extraocular muscles (CFEOM) is a rare hereditary disorder characterized by congenital non-progressive external ophthalmoplegia due to developmental abnormalities of the oculomotor and trochlear nerves, with ptosis and restricted eye movements as main symptoms.

Explains the causative gene SLC4A11, symptoms, diagnosis, treatment including corneal endothelial transplantation, and pathophysiology of congenital hereditary endothelial dystrophy (CHED).

Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is a congenital hamartoma of the retinal pigment epithelium that is usually benign and asymptomatic. Atypical variants are associated with familial adenomatous polyposis (FAP) and play an important role as an early screening marker for colorectal cancer.

A heterogeneous group of disorders caused by genetic abnormalities of the neuromuscular junction. It presents at birth or in childhood with easy fatigability, ptosis, ophthalmoplegia, and limb muscle weakness, and treatment is based on the genetic subtype.

Congenital nasolacrimal duct obstruction is a congenital blockage of the tear drainage system primarily caused by membranous obstruction at the lower end of the nasolacrimal duct, occurring in 6–20% of newborns. Approximately 90% resolve spontaneously by 12 months of age, but persistent cases are treated with conservative therapy such as lacrimal sac massage (Crigler method), probing, or dacryoendoscopic surgery.

Congenital nasolacrimal duct obstruction is an obstruction of the lacrimal drainage system occurring in 6–20% of newborns, primarily due to membranous obstruction of the valve of Hasner. Most cases resolve spontaneously within the first year of life, but persistent cases may require surgical treatments such as probing or stent placement.

Congenital palsy of the oculomotor nerve (third cranial nerve) is a pediatric ophthalmologic condition presenting with ptosis, exotropia, and limited eye movement. It is primarily caused by peripheral nerve injury during the perinatal period, and early intervention is important to prevent amblyopia.

Congenital rubella syndrome (CRS) is a congenital anomaly caused by maternal rubella infection during early pregnancy, characterized by the triad of cataracts, congenital heart disease, and hearing loss. Ocular symptoms are the most frequent, including pigmentary retinopathy, glaucoma, and microphthalmia.

A non-progressive congenital retinal dysfunction with a nearly normal fundus, diagnosed by ERG. It is classified into two types: complete (cCSNB) and incomplete (iCSNB), with X-linked recessive inheritance being the most common.

Explains the decorin gene mutation, symptoms, diagnosis, treatment including penetrating keratoplasty, and pathophysiology of congenital stromal corneal dystrophy (CSCD).

A condition in which silver deposits in the conjunctiva and cornea due to chronic exposure to silver-containing compounds. Causes include occupational exposure (jewelry making, photography development, dentistry) and long-term use of silver-containing eye drops or cosmetics. The conjunctiva appears bluish-gray, and the deep corneal layers show gray-green to golden deposits.

This article explains the diagnostic performance, technique, and indications of conjunctival biopsy for histological diagnosis of ocular sarcoidosis. It also presents the IWOS diagnostic criteria and the latest treatment strategies.

Explains smear microscopy, culture tests, and eosinophil testing of conjunctival scrapings. An essential test method for identifying the causative organism in infectious keratitis and confirming allergic conjunctival disease.

A comprehensive overview of benign tumors (e.g., papilloma), precancerous lesions (conjunctival intraepithelial neoplasia: CIN), and malignant tumors (invasive squamous cell carcinoma: SCC) arising from the conjunctival epithelium. Details include epidemiology, clinical findings, diagnostic methods, TNM classification, treatment options including surgical excision and topical chemotherapy, and pathophysiology.

A condition in which a foreign body is attached to or embedded in the conjunctiva (tarsal conjunctiva, bulbar conjunctiva, or fornix conjunctiva). It accounts for 4.4% of new ophthalmology outpatients. Common foreign bodies can be removed with moist cotton, but toxic caterpillar hairs carry a risk of vitreous penetration and require complete removal and a retinal-vitreous examination.

Definition, causes (postoperative, traumatic, congenital), diagnosis (anterior segment OCT, UBM), and treatment (excision, TCA injection, sclerotherapy, marsupialization) of conjunctival inclusion cysts.

Conjunctival intraepithelial neoplasia (CIN) is a spectrum from conjunctival epithelial dysplasia to carcinoma in situ, while invasive squamous cell carcinoma (SCC) is a malignant tumor that invades beyond the basement membrane. Ultraviolet exposure is the greatest risk factor, and surgical excision with no-touch technique and cryotherapy is the first-line treatment.

Explains the causes (surgery, trauma, inflammation, genetics), symptoms, diagnosis (slit lamp, biopsy), and treatment (steroid injection, excision, cryotherapy, radiation) of conjunctival keloid (conjunctival fibrosis).

A traumatic tear of the conjunctival tissue. Small lacerations may heal on their own with antibiotic eye drops, but large lacerations require suturing. The most important clinical point is to rule out a scleral laceration or globe rupture hidden beneath the conjunctival laceration.

Classification of conjunctival lymphangiectasia (diffuse, localized, hemorrhagic), etiology (congenital anomaly, trauma, inflammation), diagnosis (anterior segment OCT, pathology), and treatment (excision, cryocoagulation, anti-VEGF, high-frequency electrocautery).

Conjunctival malignant lymphoma is a malignant tumor caused by monoclonal proliferation of B cells, with extranodal marginal zone lymphoma (EMZL / MALT lymphoma) being the most common. It is characterized by a salmon-pink conjunctival mass, and radiation therapy is the first-line treatment for localized cases.

Conjunctival malignant melanoma is a malignant tumor derived from conjunctival melanocytes, with approximately 60-75% arising from PAM. Surgical excision using the no-touch technique and cryotherapy are the mainstays of treatment. BRAF, NF1, and NRAS mutations are major drivers, and the application of immune checkpoint inhibitors is under investigation.

A comprehensive overview of melanocytic tumors arising in the conjunctiva. It details the classification, diagnosis, treatment, and prognostic factors from benign nevi to premalignant primary acquired melanosis (PAM) and malignant conjunctival melanoma.

Conjunctival nevus is the most common benign pigmented tumor of the conjunctiva, characterized by proliferation of nevus cells in the conjunctival basal cells or subepithelium. Tapioca-like cysts are a key diagnostic feature, and the risk of malignant transformation is low, approximately 1%. Rapid growth or color change is a warning sign of malignancy.

A benign cauliflower-shaped tumor of the conjunctiva caused by HPV infection. It is typically pedunculated, but sessile types require differentiation from squamous cell carcinoma. Adding cryotherapy after excision reduces recurrence.

Conjunctival prolapse is a condition in which the bulbar conjunctiva protrudes beyond the eyelid margin. It can occur after eye trauma, as a postoperative complication, or in severe conjunctival laxity. Mild cases are managed with manual repositioning and a pressure bandage; severe or recurrent cases are treated with conjunctival excision and suturing, or conjunctival fixation surgery.

Explains the etiology (MALT antigen stimulation), diagnosis (salmon-pink lesion, flow cytometry), treatment (excision, steroids, tacrolimus, radiation), and lymphoma risk of conjunctival reactive lymphoid hyperplasia (CRLH).

Explains the causative diseases of conjunctival telangiectasia (ataxia telangiectasia, hereditary hemorrhagic telangiectasia, Fabry disease, rosacea, VHL syndrome), clinical diagnosis, differential diagnosis, and treatment.

A general term for inflammation of the conjunctiva. It is broadly classified into infectious (viral, bacterial, chlamydial) and non-infectious (allergic, toxic, etc.) types, with hyperemia, discharge, and foreign body sensation as the main symptoms.

Explains the definition, symptoms, pathophysiology, diagnosis, and treatment of conjunctivochalasis. Covers the three mechanisms of tear dynamics disorders, association with MGD, and everything from eye drop therapy to surgical therapies (resection, suturing, cauterization, and HFR-ES).

A general term for corneal and conjunctival disorders caused or triggered by contact lens wear. The main mechanisms include mechanical trauma, hypoxia, inadequate lubrication, immune reactions, and microbial infection. Identifying the cause through fluorescein staining patterns is key to diagnosis.

Contact lens intolerance is a general term for a condition in which ocular surface disorders caused by contact lens wear become chronic, making continued lens wear difficult. Diagnosis is key by estimating the cause based on fluorescein staining patterns, and the mainstays of treatment are discontinuation of lens wear, improved lens care, and appropriate eye drop therapy.

Contact lens peripheral ulcer (CLPU) is a non-infectious immune-inflammatory corneal infiltration that occurs in the peripheral cornea associated with contact lens wear. It is based on the host response to bacterial components such as Staphylococcus aureus. This article systematically explains the differentiation from microbial keratitis, discontinuation of contact lenses, use of antibiotic eye drops, and management with low-dose steroids.

Contact lens peripheral ulcer (CLPU) is a non-infectious immune-inflammatory corneal infiltration that occurs in the peripheral cornea associated with contact lens wear. It is based on the host response to bacterial components such as Staphylococcus aureus. This article systematically explains the differentiation from microbial keratitis, discontinuation of contact lenses, use of antibiotic eye drops, and management with low-concentration steroids.

Contact lens-induced acute red eye (CLARE) is a non-infectious inflammatory reaction characterized by acute onset of hyperemia, pain, and corneal infiltration during or after contact lens wear (especially overnight extended wear). The most important step is to differentiate it from infectious keratitis. Immediate discontinuation of contact lens use and steroid eye drops are the mainstays of treatment.

This article explains the definition, causes, diagnosis, and treatment of dry eye induced by contact lens (CL) wear (CLIDE). Based on the Dry Eye Clinical Practice Guidelines (Jpn J Ophthalmol 2019), TFOS DEWS III treatment algorithm, and TFOS Lifestyle report, it comprehensively describes tear film-oriented diagnosis (TFOD), tear film-oriented treatment (TFOT), CL material changes, and care improvements.

Standard technique for anterior capsulotomy in cataract surgery. Creates a circular opening in the anterior lens capsule to achieve stable fixation of the intraocular lens.

Explains the principles, charts, and clinical significance of contrast sensitivity testing. Useful for diagnosing posterior capsule opacification, cataracts, optic nerve diseases, and other conditions that can cause haze even when visual acuity is normal.

This article explains the evaluation of convergence ability using the near point of convergence (NPC) test and jump convergence test, as well as the diagnosis and treatment of convergence insufficiency, convergence paralysis, and convergence spasm.

Convergence insufficiency (CI) is a binocular vision disorder in which the ability to turn both eyes inward for near vision is reduced, causing eye strain, double vision, and headaches. Convergence training and prism glasses are the main treatments, but if accommodative insufficiency is also present, environmental improvements and appropriate spectacle prescription should be prioritized.

A binocular vision disorder in which the eyes' ability to converge during near vision is insufficient, causing eye strain, double vision, and headaches. Main treatments include convergence exercises and prism glasses. It occurs across a wide age range, from children to adults.

Cornea farinata is an age-related change in which fine dust-like opacities appear bilaterally in the deep corneal stroma just anterior to Descemet's membrane. It is usually asymptomatic and requires no treatment. Differentiation from Fuchs endothelial corneal dystrophy is important.

Explanation of the causes (amiodarone, Fabry disease, ROCK inhibitors, methotrexate), clinical findings, diagnosis (slit-lamp microscopy, α-gal A activity), pathophysiology (centripetal migration of limbal stem cells), and treatment of cornea verticillata.

This article explains the definition, immune privilege, epithelial/endothelial classification, rejection rates by PKP/DALK/DSAEK/DMEK, risk factors (including vaccine-related), Khodadoust line, differential diagnosis, steroid/CsA treatment, and HLA matching for corneal allograft rejection and failure.

An examination that uses fluorescein, rose bengal, and lissamine green to visualize and quantify epithelial damage in the cornea and conjunctiva. It is essential for diagnosing dry eye, assessing subtypes, and the initial evaluation of infectious keratitis.

Explains the viscoelastic properties of the cornea and their measurement methods (ORA, Corvis ST, Brillouin microscopy), as well as clinical applications for early diagnosis of keratoconus and refractive surgery.

A complication in which hemosiderin deposits in the corneal stroma after hyphema, causing a yellowish-brown corneal opacity. It tends to occur with traumatic hyphema, especially in cases with sustained elevated intraocular pressure.

A comparative explanation of the two major corneal collagen cross-linking (CXL) techniques: Epi-off (epithelium-off) and Epi-on (transepithelial). Covers the standard Dresden protocol, accelerated protocols, indications, procedures, outcomes, and complications for each method.

Detailed explanation of corneal cross-linking (CXL) indications, surgical techniques (Dresden protocol, accelerated CXL, PACK-CXL), effects, complications, and latest research. A minimally invasive procedure that halts the progression of progressive keratoconus and post-LASIK corneal ectasia.

A shallow saucer-shaped depression in the peripheral cornea caused by disruption of the tear film due to a limbal elevation. It usually resolves quickly with appropriate lubrication, but if left untreated, it can lead to perforation.

A congenital benign choristoma that commonly occurs at the corneal limbus. It frequently complicates amblyopia due to oblique astigmatism, and refractive correction and occlusion therapy are the mainstays of treatment. For cosmetic purposes, superficial keratectomy combined with lamellar keratoplasty may be performed.

A comprehensive explanation of the corneal donation process, donor eligibility criteria, the role of eye banks, tissue evaluation and preservation, and the legal framework.

Explanation of the principle, device types, measurement parameters (cell density, CV value, hexagonality), normal values and abnormal thresholds of corneal endothelial cell examination (specular microscope), and findings of Fuchs endothelial corneal dystrophy. It is an essential test before cataract surgery.

A condition in which the entire corneal epithelium is lost, and one of the most frequent ocular traumas in ophthalmic emergencies. Simple cases heal within a few days with antibiotic eye drops and hyaluronic acid eye drops, but persistent epithelial defects (PED) lasting more than one week require investigation of the cause.

An anterior corneal dystrophy characterized by abnormal thickening and deformation of the corneal epithelial basement membrane, producing characteristic patterns called map (geographic lines), dot (punctate opacities), and fingerprint (fingerprint lines). It is a major cause of recurrent corneal erosion and is also relevant to ocular surface management before cataract surgery.

An evidence-based explanation of the symptoms, causes, diagnosis, and treatment of corneal epithelial defect (simple erosion, recurrent erosion, persistent epithelial defect).

This article explains the types, diagnosis, and removal techniques (foreign body needle, drill, forceps) of corneal foreign bodies, as well as postoperative management. It covers essential knowledge for ophthalmic emergencies, from rust ring formation due to iron foreign bodies to infection risk from vegetative foreign bodies.

This article explains the types, diagnosis, removal techniques (foreign body needle, drill, forceps), and postoperative management of corneal foreign bodies. It covers essential knowledge for ophthalmic emergencies, from rust ring formation due to iron foreign bodies to infection risk from vegetative foreign bodies.

An intraoperative complication during cataract surgery (phacoemulsification) in which the corneal incision is thermally damaged by friction heat around the ultrasound tip. It can cause wound closure insufficiency and high astigmatism.

A benign raised fibrous lesion on the corneal surface. It can be secondary, developing after trauma or surgery, or primary, associated with conditions such as Lowe syndrome. Although rare, it can cause visual impairment.

A detailed explanation by a specialist of the causes of corneal leukoma (infections, trauma, inflammation, degenerative diseases), severity classification (nebula, macula, leukoma), diagnostic methods, treatments such as corneal transplantation and PTK, and the latest research on losartan eye drops.

A specialist explains in detail the causes of corneal neovascularization (infection, hypoxia, chemical trauma, LSCD), pathophysiology (VEGF, angiogenic privilege), treatments such as anti-VEGF therapy, FND, and MICE, and the latest research on gene therapy and nano DDS.

A surgical treatment that transfers healthy donor nerves to the cornea to restore sensation in neurotrophic keratopathy (epithelial damage due to decreased or absent corneal sensation). There are direct and indirect methods, aiming for long-term stabilization of corneal sensation and ocular surface.

A clinical finding in which corneal nerves are observed to be thick and prominent up to the central cornea. It is associated with systemic diseases such as multiple endocrine neoplasia type 2B (MEN2B) and corneal diseases such as keratoconus and Acanthamoeba keratitis. This finding can be an important clue for early detection of undiagnosed MEN2B.

Explanation of the principle, procedure, and normal values of the corneal sensitivity test (Cochet-Bonnet esthesiometer), and differential diagnosis of decreased corneal sensitivity.

A group of hereditary diseases in which abnormal proteins deposit in the corneal stroma, primarily due to TGFBI gene mutations. Includes lattice corneal dystrophy, granular corneal dystrophy, and macular corneal dystrophy.

A new surgical technique for corneal ectasia such as keratoconus, in which donor corneal tissue is inserted into the stroma to improve corneal shape. It is attracting attention as a highly biocompatible treatment option that replaces synthetic ICRS.

A non-invasive examination technique that measures and visualizes the shape of the corneal surface. Devices based on multiple principles such as Placido rings, Scheimpflug cameras, and anterior segment OCT are available, and are essential for screening keratoconus and planning refractive surgery.

This article explains the principles of corneal topography, device classifications (Placido, Scheimpflug, anterior segment OCT), corneal shape indices, keratoconus screening, and progression assessment using the ABCD classification. It is an essential test for preoperative evaluation in refractive surgery.

This article explains the definition of corneal allograft rejection after corneal transplantation, the three types (epithelial, stromal, and endothelial), Khodadoust line, risk factors, incidence rates by PKP/DALK/DSAEK/DMEK, and standard treatment including frequent steroid eye drops, mini-pulse therapy, and systemic cyclosporine or tacrolimus.

Corneal warpage is a change in corneal shape caused by mechanical compression and hypoxia due to long-term wear of contact lenses (especially hard CLs). It becomes an issue during screening before refractive surgery, and confirming shape stability after discontinuing CL use is key to evaluating surgical eligibility. Differentiation from intentional warpage due to orthokeratology is also important.

A technique in which irrigation fluid is injected into the corneal stroma to swell the cornea, assisting in the closure of clear corneal incisions (CCI) during cataract surgery. It is widely used to prevent postoperative endophthalmitis.

Corneoconjunctival dermoid is a congenital choristoma, a benign tumor commonly occurring at the limbus. Attention should be paid to association with Goldenhar syndrome. Standard treatment involves early visual management to prevent amblyopia and surgery combined with superficial keratoplasty.

Cortical blindness is loss of vision due to damage to the bilateral occipital visual cortex, and Anton syndrome is a neuro-ophthalmic disorder in which cortical blindness is accompanied by denial of visual loss (anosognosia) and confabulation.

A rare 4-repeat tauopathy characterized by progressive atrophy of the cerebral cortex and basal ganglia. It presents with movement disorders, cortical dysfunction, and oculomotor abnormalities; definitive diagnosis is only possible through postmortem pathological examination.

A test in which a cotton thread impregnated with phenol red is placed on the lower eyelid, and tear secretion over 15 seconds is measured in mm. A dry-eye screening method that can be performed in less time and with less invasiveness than the Schirmer test.

White lesions caused by swelling of the nerve fiber layer due to microinfarction of retinal arterioles. They are ocular signs of various underlying diseases such as hypertension, diabetes, collagen disease, and infections, and usually resolve within 6 to 12 weeks.

The cover test is the gold standard objective examination for evaluating the presence, type, and degree of ocular misalignment (strabismus). This article explains the procedures and interpretation of the cover test, cover-uncover test, alternate cover test, and prism cover test.

COVID conjunctivitis is an ocular symptom associated with SARS-CoV-2 infection, presenting as follicular conjunctivitis that often resolves spontaneously. It occurs in 1–3% of COVID-19 patients and may rarely be the initial symptom.

This article explains the impact of the COVID-19 pandemic on glaucoma care, including the introduction and challenges of telemedicine, limitations of clinical examinations, changes in treatment adherence, and transformations in surgical implementation systems.

Follicular dendritic cell sarcoma (FDCS) is an extremely rare low-grade sarcoma that occurs intracranially or intraorbitally. Invasion of the cavernous sinus or clivus can cause ocular symptoms such as diplopia, visual loss, proptosis, and ptosis.

A disease in which inflammation of cranial nerves causes nerve destruction or demyelination. Causes are diverse, including infectious, autoimmune, neoplastic, vascular, and idiopathic. When multiple cranial nerves are affected, it is called polyneuritis cranialis.

A group of disorders in which premature fusion of cranial sutures leads to skull deformity and neurological complications. Includes Crouzon syndrome, Apert syndrome, Pfeiffer syndrome, etc., requiring multidisciplinary management.

Explains the methods for creating incisions in cataract surgery (phacoemulsification). Summarizes the techniques for clear corneal incision, sclerocorneal incision, and transconjunctival single-plane sclerocorneal incision, as well as criteria for selecting location, size, and structure, and key points for preventing complications.

A benign corneal degeneration in which polygonal gray-white opacities appear in the posterior stroma with aging. The appearance resembles crocodile skin, but it is asymptomatic and requires no treatment.

An extremely rare visual field defect in which lesions occur above the calcarine sulcus on one side and below the calcarine sulcus on the opposite side of both occipital lobes, resulting in homonymous loss of two quadrants on a diagonal line. Also called checkerboard visual field defect, mainly caused by embolism of the calcarine artery.

Infectious keratitis occurring after corneal crosslinking (CXL). The incidence is low at 0.12–0.21%, but it can lead to corneal perforation and severe visual impairment. Treatment of infectious keratitis with PACK-CXL is also discussed.

A complication in which tractional retinal detachment develops or progresses after intravitreal anti-VEGF injection for proliferative retinopathy such as proliferative diabetic retinopathy. The incidence is about 5%, and it causes rapid vision loss within 1 to 6 weeks after injection.

Infectious chorioretinitis caused by Cryptococcus neoformans. It commonly occurs in immunocompromised patients such as those with AIDS and may present as an initial ocular symptom of meningitis. Diagnosis and treatment are explained.

Cryptophthalmos is a rare congenital anomaly in which fused eyelids cover the eyeball and the palpebral fissure is absent. There are three types: complete, incomplete, and abortive, and it is closely associated with Fraser syndrome.

A general term for a heterogeneous group of diseases characterized by crystal deposits in any layer of the retina. It includes hereditary diseases such as Bietti crystalline dystrophy (BCD) and cystinosis, as well as drug-induced crystal deposits such as those caused by tamoxifen.

Explains the current state and future outlook of AI diagnosis in ophthalmology. Deep-learning-based automatic analysis of fundus photographs and OCT is used for screening diabetic retinopathy, glaucoma, and age-related macular degeneration, and shows accuracy comparable to specialists. Cost-effectiveness, challenges, and ethical aspects are also summarized.

This article explains the indications, surgical techniques, complications, and mechanisms of action of transscleral cyclophotocoagulation (TS-CPC), micropulse transscleral cyclophotocoagulation (MP-CPC), slow coagulation continuous-wave TSCPC (SC-TSCPC), endoscopic cyclophotocoagulation (ECP), and high-intensity focused ultrasound circular cyclocoagulation (HIFU-UCCC), including the latest case reports and histological findings.

Comprehensive explanation of cyclodialysis cleft: pathophysiology, causes, diagnosis (gonioscopy, UBM, AS-OCT), pharmacotherapy, laser treatment, surgery (cyclodialysis repair), and mechanism of intraocular pressure elevation after closure.

Cyclopia is the most severe form of alobar holoprosencephaly, a lethal congenital anomaly characterized by a single orbit in the center of the face. The main pathogenesis is disruption of the Sonic Hedgehog pathway.

This article explains the use, efficacy, side effects, and drug interactions of the calcineurin inhibitor cyclosporine in ophthalmology for non-infectious uveitis.

Cystic fibrosis (CF) is a systemic disease caused by mutations in the CFTR gene, and is associated with various ocular complications such as xerophthalmia due to vitamin A deficiency, CFRD-related retinopathy, and CFTR modulator-related cataracts.

Cystinosis is a lysosomal storage disease characterized by the accumulation of cystine within cells throughout the body. Ocular manifestations include photophobia and visual impairment due to corneal cystine crystal deposition, and treatment with cysteamine eye drops is effective.

A condition in which fluid accumulates mainly in the outer plexiform layer of the macula due to breakdown of the blood-retinal barrier, resulting in cystoid changes. Causes include diabetic retinopathy, retinal vein occlusion, post-cataract surgery, and drug-induced factors.

A postoperative complication in which cystoid fluid accumulation occurs in the outer plexiform and inner nuclear layers of the macula after cataract surgery, causing vision loss. Also called Irvine-Gass syndrome, it often resolves spontaneously, but if it becomes chronic, it can lead to permanent visual impairment.

Cytomegalovirus (CMV) corneal endotheliitis is a disease in which reactivation of CMV causes inflammation of the corneal endothelial cells. It is a chronic, recurrent anterior segment infection characterized by coin-shaped keratic precipitates, corneal edema, and elevated intraocular pressure.

Diagnosis and treatment of cytomegalovirus (CMV) anterior uveitis and corneal endotheliitis in immunocompetent individuals. Characterized by high intraocular pressure, coin-shaped keratic precipitates, linear keratic precipitates, and corneal endothelial cell loss. Treatment mainly involves ganciclovir gel eye drops and oral valganciclovir.

Necrotizing retinitis of the full thickness of the retina caused by cytomegalovirus (CMV). It is an opportunistic infection that occurs in immunocompromised individuals such as those with AIDS, post-organ transplant, or on immunosuppressive therapy. The mainstays of treatment are anti-CMV therapy centered on ganciclovir and prevention of retinal detachment.