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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.

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.

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.

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.

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.

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.

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.

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.

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.

Chemical injuries of the conjunctiva and cornea are ophthalmic emergencies requiring immediate irrigation. Alkali agents have high deep-tissue penetration and tend to cause severe damage. Severity is assessed using the Kinoshita classification or Roper-Hall classification, and management proceeds in stages from conservative treatment in the acute phase to surgical ocular surface reconstruction in the cicatricial phase.

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.

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 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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

Congenital nasolacrimal duct obstruction is a congenital blockage of the tear drainage system primarily caused by a membranous obstruction at the lower end of the nasolacrimal duct, occurring in 6–20% of newborns. About 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 lacrimal endoscopy surgery.

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.

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.

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.

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.

Definition, symptoms, pathophysiology, diagnosis, and treatment of conjunctivochalasis according to Japanese standards. Covers Norihiko Yokoi's proposed lacrimal meniscus reconstruction (3-block resection), tear dynamics disorders common in the elderly, association with MGD, and latest treatments including 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-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.

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 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.

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).

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.

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.

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.

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.

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.

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

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.

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.