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Macular corneal dystrophy (MCD) is an autosomal recessive corneal dystrophy caused by mutations in the CHST6 gene, leading to diffuse accumulation of glycosaminoglycans (keratan sulfate) in the corneal stroma. Bilateral vision loss occurs from around 10 to 30 years of age. Treatment includes deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PKP).

A macular hole (MH) is a full-thickness defect of the retina at the fovea, causing decreased central vision and metamorphopsia. With vitrectomy, internal limiting membrane peeling, and gas tamponade, 91–98% of cases achieve closure, and visual improvement persists for up to 3 years postoperatively.

Explains the principles, measurement parameters (GCC, GCIPL), diagnostic ability, progression detection, floor effect limitations, and OCTA prospects of macular OCT (optical coherence tomography) in glaucoma diagnosis. Includes the importance of comprehensive evaluation by combining with RNFL analysis.

A bilateral retinal disease characterized by perifoveal capillary telangiectasia and neurodegeneration. Müller cell dysfunction is considered the origin of the pathology, slowly progressing to ellipsoid zone loss and subretinal neovascularization.

Characteristic retinal changes associated with severe malaria (especially cerebral malaria) caused by Plasmodium falciparum. It presents with retinal whitening, vascular discoloration, retinal hemorrhages, and optic disc edema, and is an important clinical finding for improving diagnostic accuracy of cerebral malaria.

A rare secondary angle-closure glaucoma in which aqueous humor is misdirected posteriorly, causing forward displacement of the iris-lens diaphragm, angle closure, and elevated intraocular pressure. It often occurs after filtration surgery.

A malignant tumor arising from melanocytes in the eyelid skin. It is rare, accounting for less than 1% of all cutaneous melanomas, but pigmented lesions with a diameter of 7 mm or more require referral to a specialist. Prognosis depends largely on tumor thickness and stage.

A comprehensive overview of the etiology, diagnosis, and treatment of descemetocele (anterior bulging of Descemet's membrane due to corneal stromal defect) and corneal perforation, ranging from conservative to surgical management.

This article explains the diagnosis and treatment of a dropped nucleus, a condition where the lens nucleus falls into the vitreous cavity during cataract surgery. It details the indications and techniques of vitrectomy (PFCL method, kebab method), secondary IOL fixation, and visual prognosis for this intraoperative complication with an incidence of 0.1–0.28%.

Extrusion of intracorneal ring segments (ICRS) is a complication in which the ring protrudes due to progressive corneal stromal thinning and epithelial breakdown. It accounts for about half of all removal cases and is preceded by ring migration or corneal melting. Recovery is possible with removal surgery.

Overcorrection after LASIK can cause difficulty with near vision, eye strain, and decreased quality of vision. The Refractive Surgery Guidelines (8th edition) set a goal of avoiding postoperative overcorrection. Conservative correction is the first choice; additional interventions such as enhancement surgery, PRK, or TG-LASIK should be performed with careful indication assessment.

Submacular hemorrhage (SMH) is a condition with poor visual prognosis in which blood accumulates between the retinal pigment epithelium and the neurosensory retina. Age-related macular degeneration is the most common cause, and treatment options include anti-VEGF therapy, pneumatic displacement, and vitrectomy.

A type of extracapsular cataract extraction in which the nucleus is removed through a self-sealing corneoscleral tunnel incision. It requires no sutures, is low-cost and short-duration, and is widely used especially in developing countries.

A congenital neurogenic ptosis in which the drooping eyelid elevates with jaw movement. Caused by abnormal connections between the trigeminal and oculomotor nerves, accounting for 2–13% of congenital ptosis.

An autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene. Ocular manifestations frequently include ectopia lentis, with increased risk of glaucoma, cataract, and retinal detachment.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene, with approximately 60% of patients developing ectopia lentis. It is frequently associated with high myopia, retinal detachment, glaucoma, and cataract. Regular dilated eye examinations and early intervention are crucial for visual prognosis.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene, with approximately 60% of patients developing ectopia lentis. It is frequently associated with high myopia, retinal detachment, glaucoma, and cataract. Regular examinations under dilated pupils and early intervention are crucial for visual prognosis.

A recurrent inflammatory disease characterized by sterile infiltration and ulceration in the peripheral cornea due to a type III allergic reaction to antigens of staphylococci that normally reside on the eyelids. It is frequently associated with blepharitis.

Mucopolysaccharidosis type VI is a lysosomal storage disease caused by deficiency of arylsulfatase B, leading to accumulation of dermatan sulfate. It is characterized by progressive corneal opacification, glaucoma, and optic neuropathy, without intellectual disability.

McArdle disease (glycogen storage disease type V, GSD5) is a metabolic muscle disease caused by myophosphorylase deficiency. It is characterized by reduced exercise tolerance and rhabdomyolysis, and has been reported to be associated with retinal pattern dystrophy due to impaired glycogen metabolism in the retinal pigment epithelium.

Medial canthal tendon (MCT) avulsion is an injury in which the medial eyelid tendon is torn away from its normal attachment by trauma. It often occurs with canalicular laceration, and prompt surgical repair affects functional and cosmetic outcomes.

Explanation of symptoms, diagnosis, and treatment for fractures of the medial orbital wall (lamina papyracea of the ethmoid bone). The medial wall, being the thinnest of the orbital walls, is prone to fracture from blunt trauma, causing diplopia and enophthalmos.

This article explains the medical expense subsidy system for designated intractable diseases in the field of ophthalmology, including target diseases, application procedures, maximum out-of-pocket amounts, and renewal of the recipient certificate.

This article explains the current state of medical malpractice lawsuits in neuro-ophthalmology, diagnoses prone to litigation (such as cerebrovascular lesions, intracranial tumors, giant cell arteritis), measures to prevent oversight of emergency conditions, and key points of risk management.

This article explains a rare intraocular tumor arising from the nonpigmented ciliary epithelium, including its clinical features in children, differentiation from retinoblastoma, and treatment strategies.

An autosomal dominant corneal dystrophy characterized by multiple microcysts within the corneal epithelium due to mutations in the KRT3 or KRT12 genes. Onset occurs early in life, but symptoms are usually mild and may include recurrent corneal erosions.

A non-progressive congenital anomaly in which the horizontal corneal diameter is 13 mm or more (12 mm or more in newborns). X-linked recessive inheritance is most common, caused by a mutation in the CHRDL1 gene leading to deficiency of ventroptin, a BMP-4 antagonist. Differentiation from congenital glaucoma (buphthalmos) is important.

A chronic diffuse abnormality of the meibomian glands, characterized by terminal duct obstruction and/or qualitative or quantitative changes in glandular secretions. It is the most common cause of evaporative dry eye, affecting 10–30% of individuals aged 50 years or older in Japan.

A rare paraneoplastic syndrome associated with melanoma, in which retinal function is impaired by an autoimmune mechanism involving anti-retinal bipolar cell antibodies.

A rare granulomatous neurocutaneous disease characterized by the triad of recurrent orofacial edema, facial nerve palsy, and fissured tongue. It occurs in 0.08% of the general population, and no curative treatment has been established.

A general term for conjunctivitis in which a membrane composed of fibrin and inflammatory exudate forms on the conjunctival surface. True membranes embed into the conjunctival epithelium and bleed upon removal, whereas pseudomembranes adhere to the surface and can be easily removed. Adenoviral conjunctivitis is the most common cause.

A rare and highly malignant neuroendocrine tumor derived from Merkel cells. It commonly occurs in the head and neck region, with 5–10% arising on the eyelid. It grows rapidly and tends to metastasize via the lymphatic system.

A group of diseases that cause structural and functional changes in the cornea due to genetic enzyme deficiencies or acquired metabolic dysregulation (e.g., diabetes). Abnormal accumulation of metabolic products impairs corneal transparency, leading to vision loss. Diabetic keratopathy is the most common clinically.

Metabolic syndrome (visceral obesity + hyperglycemia, hypertension, dyslipidemia) increases the risk of various eye diseases such as diabetic retinopathy, age-related macular degeneration, retinal vein occlusion, glaucoma, and central serous chorioretinopathy. Improving lifestyle habits also contributes to better ophthalmic prognosis.

A rare condition in which systemic malignant tumors metastasize hematogenously to the extraocular muscles. Primary tumors include breast cancer, lung cancer, and cutaneous melanoma, causing restricted eye movement and diplopia. Prognosis is poor, and treatment is mainly palliative.

A condition in which systemic malignant tumors, such as lung cancer and breast cancer, metastasize hematogenously to the choroid. It is characterized by yellowish-white flat lesions and marked serous retinal detachment, with radiation therapy and systemic chemotherapy being the main treatment options.

Keratitis caused by methamphetamine (stimulant) abuse. Pharmacological vasoconstriction, corneal hypoesthesia, and tear film dysfunction, combined with chemical toxicity of contaminants and behavioral factors, cause complex corneal damage. It has features of neurotrophic keratopathy and is frequently complicated by infectious keratitis.

The most widely used immunomodulatory drug for non-infectious uveitis. It is an antimetabolite with antifolate activity, used globally as a first-line steroid-sparing agent.

A rare group of genetic disorders characterized by microcephaly and chorioretinopathy. Mutations in four genes (TUBGCP6, PLK4, TUBGCP4, KIF11) cause these conditions, which may involve visual impairment and intellectual disability.

Microperimetry (microperimeter) is a visual function test that integrates fundus imaging and perimetry. It accurately maps light sensitivity at specific retinal locations, enabling structure-function correlation analysis.

Microphthalmia is a congenital ocular developmental anomaly in which the axial length of the eye is at least two standard deviations shorter than the age-adjusted mean. It is often associated with complications such as coloboma, cataract, and glaucoma, requiring early intervention and long-term management through multidisciplinary collaboration.

Microspherophakia is a congenital malformation characterized by a decreased equatorial diameter and increased anteroposterior diameter of the lens. Lenticonus is a congenital anomaly in which a conical protrusion occurs on the anterior or posterior surface of the lens. Both are caused by abnormalities of the zonules or lens capsule development and are often complicated by secondary glaucoma, high myopia, and cataracts.

Microsporidia are obligate intracellular spore-forming fungi that cause ocular infections presenting as two clinical forms: keratoconjunctivitis and stromal keratitis. They affect not only immunocompromised individuals but also immunocompetent individuals, and are often misdiagnosed as herpetic keratitis. Special staining of corneal scrapings and confocal microscopy are useful for diagnosis.

Cardenolides (cardiac glycosides) in the milky sap (latex) of plants in the genus Asclepias inhibit Na+/K+-ATPase in the corneal endothelium, causing corneal edema due to impaired corneal pump function. Recovery usually occurs within a few days with eye irrigation, steroid eye drops, and hypertonic agents.

A classic brainstem crossed syndrome presenting with ipsilateral abducens and facial nerve palsy and contralateral hemiplegia due to a unilateral lesion in the ventral caudal pons. This article explains the definition, symptoms, causes, diagnosis, and treatment.

Miller Fisher syndrome (MFS) is a variant of Guillain-Barré syndrome, an autoimmune peripheral neuropathy characterized by the triad of ophthalmoplegia, ataxia, and areflexia. Anti-GQ1b antibodies are involved in its pathogenesis, and most cases resolve spontaneously.

Mitomycin intravascular chemoembolization (MICE) is a new treatment for corneal neovascularization and lipid keratopathy that affect visual function. Mitomycin C (MMC) is selectively injected into corneal neovessels, inducing vascular occlusion through irreversible cytotoxicity to the vascular endothelium.

A congenital anomaly in which an embryonic remnant of the hyaloid artery persists on the posterior lens capsule. It is the mildest change of persistent fetal vasculature (PFV) and usually does not affect visual function.

Modified Osteo-Odonto-Keratoprosthesis (MOOKP) is a keratoprosthesis that uses the patient's own tooth and alveolar bone as a biological support. It is performed as a multi-stage surgery combining an oral mucosal graft and a PMMA optical cylinder, as a final visual function restoration method for bilateral end-stage ocular surface diseases.

Moebius syndrome is a rare congenital disorder characterized by horizontal gaze palsy and facial paralysis due to congenital dysfunction of the sixth and seventh cranial nerves. It is classified under congenital cranial dysinnervation disorders (CCDDs).

A central nervous system demyelinating disease caused by autoantibodies against myelin oligodendrocyte glycoprotein (MOG). Its main phenotypes are optic neuritis, ADEM, and myelitis. It is a disease concept independent of MS and AQP4-positive NMOSD. International diagnostic criteria were established in 2023.

An eye movement disorder in which one eye is limited in upward gaze in both adduction and abduction. It is often congenital and presents with hypotropia, ptosis, and abnormal head posture.

A sensory adaptation state in which foveal fusion is absent due to a macular scotoma in one eye, but peripheral fusion is maintained. Externally normal and asymptomatic, but associated with lack of fine stereopsis and mild amblyopia. Often recognized as a favorable outcome after strabismus surgery.

Explains the types, materials, optical designs, power calculation, surgical outcomes, and postoperative complications of monofocal intraocular lenses (IOLs), which are most commonly used in cataract surgery. Hydrophobic acrylic is the standard material, and there are various options such as aspheric design and toric design.

Monovision is a method to compensate for presbyopia by correcting one eye for distance and the other for near vision. This article details its application with contact lenses, LASIK, and cataract IOLs, dominant eye setting, effects on stereopsis, and the trial wear procedure.

Mooren's ulcer (rodent corneal ulcer) is an idiopathic autoimmune peripheral corneal ulcer that progresses along the corneal limbus. It is characterized by an arcuate ulcer with undermined edges, and the sclera is not involved. An autoimmune reaction against calgranulin C in the corneal stroma is thought to be involved in the pathogenesis.

A condition in which a hypermature cataract progresses and the cortex liquefies, causing the hard nucleus to sink to the bottom of the lens capsule. It is common in developing countries and carries a risk of complications such as phacolytic glaucoma and phacoanaphylactic uveitis.

This article explains the characteristic optic disc findings of morning glory disc anomaly (MGDA), systemic complications (transsphenoidal encephalocele, moyamoya disease), management of retinal detachment, and differentiation from glaucoma.

A congenital optic disc anomaly characterized by funnel-shaped excavation of the optic disc, white glial tissue, and radial blood vessels. It is frequently associated with retinal detachment and is known to be related to transsphenoidal encephalocele.

A rare higher-order visual processing disorder in which moving objects cannot be visually perceived. Caused by damage to the V5/MT area, it presents with unique symptoms such as moving objects appearing as a series of still frames or disappearing from view.

Mpox (monkeypox) is a zoonotic disease caused by the monkeypox virus (MPXV), a member of the Orthopoxvirus genus. Ophthalmic complications (MPXROD) primarily affect the eyelids, conjunctiva, and cornea, and can cause ulcerative keratitis and immune stromal keratitis. Severe cases may lead to permanent vision loss due to corneal scarring.

Mucus fishing syndrome is a chronic inflammatory ocular surface disease caused by repeatedly manually removing mucus from the conjunctival fornix. The core pathology is a vicious cycle in which mechanical trauma stimulates goblet cells to increase mucus production, which in turn triggers further removal behavior.

Muir-Torre syndrome (MTS) is a subtype of Lynch syndrome, an autosomal dominant inherited disorder that combines sebaceous skin tumors and cancers of internal organs. It is caused by mutations in DNA mismatch repair genes, and early diagnosis and surveillance of multiple organs are important.

A chronic bilateral disease presenting with multiple inflammatory lesions at the level of the retinal pigment epithelium and choriocapillaris. It is distinguished from punctate inner choroidopathy by the presence of anterior chamber and vitreous inflammation.

Multifocal (bifocal/progressive) contact lenses are contact lenses designed primarily for presbyopia correction, integrating multiple focal points for distance and near vision into a single lens. This article explains the differences in design (concentric, EDOF, HCL), actual prescription procedures, selection of candidates, and management of complications.

A comprehensive explanation of multifocal intraocular lenses (trifocal, EDOF, accommodating IOL) in cataract surgery, including classification, optical principles, selection criteria, visual outcomes, complication management, and mix-and-match strategies.

An acute inflammatory disease typically affecting one eye in young myopic women. Transient dysfunction of the outer retina and ellipsoid zone leads to gray-white spots that resolve spontaneously within weeks.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system that presents with various ocular symptoms such as optic neuritis and internuclear ophthalmoplegia. Diagnosis is based on the McDonald criteria, including MRI and cerebrospinal fluid analysis, and management involves steroid pulse therapy and disease-modifying therapies.

An antimetabolite immunosuppressant used for non-infectious uveitis. It selectively inhibits IMPDH to suppress lymphocyte proliferation and is positioned as a steroid-sparing agent with a favorable side effect profile.

A mucocutaneous disease associated with Mycoplasma pneumoniae infection. It is a distinct disease entity separate from SJS/TEN, predominantly affecting young individuals, with mucositis of the oral cavity, eyes, and genitalia as the main feature. The ocular prognosis is better than that of SJS/TEN.

The Mycotic Corneal Ulcer Treatment Trial (MUTT) is a large randomized controlled trial comparing the efficacy of topical natamycin and topical voriconazole for filamentous fungal keratitis. MUTT 1 showed superiority of natamycin (especially for Fusarium species), and MUTT 2 found no overall benefit from adding oral voriconazole.

A congenital anomaly in which nerve fibers within the retina are myelinated. It appears as brush-like white opacities on fundus examination, and is often asymptomatic, but may occasionally be associated with high myopia or amblyopia.

A congenital anomaly in which myelin sheaths are focally formed on retinal nerve fibers. Often discovered incidentally on fundus examination as brush-like white opacities, mostly asymptomatic and requiring no treatment.

Myopia is a refractive error in which the refractive power is excessive relative to the axial length, resulting in decreased distance vision. This article provides a comprehensive explanation from simple myopia to pathological myopia, including the latest evidence for myopia progression control treatment including low-concentration atropine eye drops (Rijusea® Mini 0.025%).

Childhood myopia is a refractive error that develops during school age, primarily caused by axial elongation. Multiple progression control therapies, including low-dose atropine eye drops, myopia management spectacles, multifocal contact lenses, and orthokeratology, have accumulated evidence.

A specific type of myopia occurring in preterm infants, primarily caused by abnormal development of the anterior segment (cornea and lens) rather than axial elongation. It is closely associated with retinopathy of prematurity (ROP) and its treatment, and the choice of treatment significantly affects refractive prognosis.

Orthokeratology (OK) is a treatment that uses specially designed hard contact lenses worn overnight to reshape the cornea, restoring uncorrected visual acuity and slowing myopia progression in children. This article explains indications, prescribing procedures, safety management, and combination with low-concentration atropine.

Choroidal neovascularization (MNV) that occurs in the fundus of pathologic myopia. It occurs in 5–11% of high myopia eyes and is the leading cause of MNV in individuals aged 50 years or younger. Intravitreal injection of anti-VEGF drugs is the first-line treatment.

A general term for tractional retinal changes that develop in highly myopic eyes with posterior staphyloma. It presents various pathologies such as retinoschisis, macular hole, and tractional retinal detachment, and advanced cases require surgical intervention.