In Northern European populations about one in 9000 people carry one of the three primary LHON mutations.

The LHON ND4 G11778A mutation dominates as the primary mutation in most of the world

with 70% of Northern European cases and 90% of Asian cases. Due to a Founder effect, the LHON ND6 T14484C mutation accounts for 86% of LHON cases in Quebec, Canada.

More than 50 percent of males with a mutation and more than 85 percent of females with a mutation never experience vision loss or related medical problems. The particular mutation type may predict the likelihood of penetrance, severity of illness and probability of vision recovery in the affected. As a rule of thumb, a woman who harbors a homoplasmic primary LHON mutation has a ~40% risk of having an affected son and a ~10% risk of having an affected daughter.

Additional factors may determine whether a person develops the signs and symptoms of this disorder. Environmental factors such as smoking and alcohol use may be involved, although studies of these factors have produced conflicting results. Researchers are also investigating whether changes in additional genes, particularly genes on the X chromosome,

Genetic tests and related research are currently being performed at Centogene AG in Rostock, Germany; John and Marcia Carver Nonprofit Genetic Testing Laboratory in Iowa City, IA; GENESIS Center for Medical Genetics in Poznan, Poland; Miraca Genetics Laboratories in Houston, TX; Asper Biotech in Tartu, Estonia; CGC Genetics in Porto, Portugal; CEN4GEN Institute for Genomics and Molecular Diagnostics in Edmonton, Canada; and Reference Laboratory Genetics - Barcelona, Spain.

This is a partial list of human eye diseases and disorders.

The World Health Organization publishes a classification of known diseases and injuries, the International Statistical Classification of Diseases and Related Health Problems, or ICD-10. This list uses that classification.

In the United States, the incidence of primary congenital glaucoma is about one in 10,000 live births. Worldwide, the incidence ranges from a low of 1:22,000 in Northern Ireland to a high of 1:2,500 in Saudi Arabia and 1:1,250 in Romania. In about two-thirds of cases, it is bilateral. The distribution between males and females varies with geography. In North America and Europe it is more common in boys, whereas in Japan it is more common in girls.

- Congenital glaucoma

- Incidence: one in every 10000-15000 live births.

- Bilateral in up to 80% of cases.

- Most cases are sporadic (90%). However, in the remaining 10% there appears to be a strong familial component.

It is usually autosomal recessive; however, importantly for family planning, it is sometimes autosomal dominant. It is a disorder thought to be caused by abnormal development of photoreceptor cells.

OMIM currently recognizes 18 types of LCA.

The gene has been associated with Joubert syndrome, as well as type 10 LCA.

Retinal dysplasia is an eye disease affecting the retina of animals and, less commonly, humans. It is usually a nonprogressive disease and can be caused by viral infections, drugs, vitamin A deficiency, or genetic defects. Retinal dysplasia is characterized by folds or rosettes (round clumps) of the retinal tissue.

Most cases of retinal dysplasia in dogs are hereditary. It can involve one or both retinas. Retinal dysplasia can be focal, multifocal, geographic, or accompanied by retinal detachment. Focal and multifocal retinal dysplasia appears as streaks and dots in the central retina. Geographic retinal dysplasia appears as an irregular or horseshoe-shaped area of mixed hyper or hyporeflectivity in the central retina. Retinal detachment occurs with complete retinal dysplasia, and is accompanied by blindness in that eye. Cataracts or glaucoma can also occur secondary to retinal dysplasia. Other causes of retinal dysplasia in dogs include infection with canine adenovirus or canine herpesvirus, or radiation of the eye in newborns.

Some pedigrees suggest inherited primary congenital is autosomal dominant but three major autosomal recessive loci have been identified:

- GLC3A – on chromosome 2 (2p21)

- GLC3B – on chromosome 1 (1p36)

- GLC3C – on chromosome 14 (14q24.3)

Norrie disease is a genetic disorder that primarily affects the eye and almost always leads to blindness. In addition to the congenital ocular symptoms, some patients suffer from a progressive hearing loss starting mostly in their 2nd decade of life, and some may have learning difficulties.

Patients with Norrie disease may develop cataracts, leukocoria (a condition where the pupils appear white when light is shone on them), along with other developmental issues in the eye, such as shrinking of the globe and the wasting away of the iris. Around 30 to 50% of them will also have developmental delay/learning difficulties, psychotic-like features, incoordination of movements or behavioral abnormalities. Most patients are born with normal hearing; however, the onset of hearing loss is very common in early adolescence. About 15% of patients are estimated to develop all the features of the disease.

The disease affects almost only male infants, because the disease is inherited X-linked recessive. Only in very rare cases, females have been diagnosed with Norrie disease as well. The exact incidence number is unknown; only a few hundred cases have been reported. It is a very rare disorder that is not associated with any specific ethnic or racial groups.

Optic disc drusen are found clinically in about 1% of the population but this increases to 3.4% in individuals with a family history of ODD. About two thirds to three quarters of clinical cases are bilateral. A necropsy study of 737 cases showed a 2.4% incidence with 2 out of 15 (13%) bilateral, perhaps indicating the insidious nature of many cases. An autosomal dominant inheritance pattern with incomplete penetrance and associated inherited dysplasia of the optic disc and its blood supply is suspected. Males and females are affected at equal rates. Caucasians are the most susceptible ethnic group. Certain conditions have been associated with disc drusen such as retinitis pigmentosa, angioid streaks, Usher syndrome, Noonan syndrome and Alagille syndrome. Optic disc drusen are not related to Bruch membrane drusen of the retina which have been associated with age-related macular degeneration.

At least one type of autosomal dominant cone-rod dystrophy is caused by mutations in the guanylate cyclase 2D gene (GUCY2D) on chromosome 17.

Aniridia is the absence of the iris, usually involving both eyes. It can be congenital or caused by a penetrant injury. Isolated aniridia is a congenital disorder which is not limited to a defect in iris development, but is a panocular condition with macular and optic nerve hypoplasia, cataract, and corneal changes. Vision may be severely compromised and the disorder is frequently associated with a number of ocular complications: nystagmus, amblyopia, buphthalmos, and cataract. Aniridia in some individuals occurs as part of a syndrome, such as WAGR syndrome (kidney nephroblastoma (Wilms tumour), genitourinary anomalies and intellectual disability), or Gillespie syndrome (cerebellar ataxia).

Aniridia may be broadly divided into hereditary and sporadic forms. Hereditary aniridia is usually transmitted in an autosomal dominant manner (each offspring has a 50% chance of being affected), although rare autosomal recessive forms (such as Gillespie syndrome) have also been reported. Sporadic aniridia mutations may affect the WT1 region adjacent to the AN2 aniridia region, causing a kidney cancer called nephroblastoma (Wilms tumor). These patients often also have genitourinary abnormalities and intellectual disability (WAGR syndrome).

Several different mutations may affect the PAX6 gene. Some mutations appear to inhibit gene function more than others, with subsequent variability in the severity of the disease. Thus, some aniridic individuals are only missing a relatively small amount of iris, do not have foveal hypoplasia, and retain relatively normal vision. Presumably, the genetic defect in these individuals causes less "heterozygous insufficiency," meaning they retain enough gene function to yield a milder phenotype.

- AN

- Aniridia and absent patella

- Aniridia, microcornea, and spontaneously reabsorbed cataract

- Aniridia, cerebellar ataxia, and mental deficiency (Gillespie syndrome)

The incidence of dominant optic atrophy has been estimated to be 1:50000 with prevalence as high as 1:10000 in the Danish population (Votruba, 1998). Dominant optic atrophy is inherited in an autosomal dominant manner. That is, a heterozygous patient with the disease has a 50% chance of passing on the disease to offspring, assuming his/her partner does not have the disease. Males and females are affected at the same rate. Although Kjer's has a high penetrance (98%), severity and progression of DOA are extremely variable even within the same family.

Though there is no treatment for Cone dystrophy, certain supplements may help in delaying the progression of the disease.

The beta-carotenoids, lutein and zeaxanthin, have been evidenced to reduce the risk of developing age related macular degeneration (AMD), and may therefore provide similar benefits to Cone dystrophy sufferers.

Consuming omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid) has been correlated with a reduced progression of early AMD, and in conjunction with low glycemic index foods, with reduced progression of advanced AMD, and may therefore delay the progression of cone dystrophy.

A corneal dystrophy can be caused by an accumulation of extraneous material in the cornea, including lipids and cholesterol crystals.

Choroideremia (; CHM) is a rare, X-linked recessive form of hereditary retinal degeneration that affects roughly 1 in 50,000 males. The disease causes a gradual loss of vision, starting with childhood night blindness, followed by peripheral vision loss, and progressing to loss of central vision later in life. Progression continues throughout the individual's life, but both the rate of change and the degree of visual loss are variable among those affected, even within the same family.

Choroideremia is caused by a loss-of-function mutation in the "CHM" gene which encodes Rab escort protein 1 (REP1), a protein involved in lipid modification of Rab proteins. While the complete mechanism of disease is not fully understood, the lack of a functional protein in the retina results in cell death and the gradual deterioration of the choroid, retinal pigment epithelium (RPE), and retinal photoreceptor cells.

As of 2017, there is no treatment for choroideremia; however, retinal gene therapy clinical trials have demonstrated a possible treatment.

Corneal dystrophy is a group of rare hereditary disorders characterised by bilateral abnormal deposition of substances in the transparent front part of the eye called the cornea.

Leber's hereditary optic neuropathy (LHON) or Leber hereditary optic atrophy is a mitochondrially inherited (transmitted from mother to offspring) degeneration of retinal ganglion cells (RGCs) and their axons that leads to an acute or subacute loss of central vision; this affects predominantly young adult males. LHON is only transmitted through the mother, as it is primarily due to mutations in the mitochondrial (not nuclear) genome, and only the egg contributes mitochondria to the embryo. LHON is usually due to one of three pathogenic mitochondrial DNA (mtDNA) point mutations. These mutations are at nucleotide positions 11778 G to A, 3460 G to A and 14484 T to C, respectively in the ND4, ND1 and ND6 subunit genes of complex I of the oxidative phosphorylation chain in mitochondria. Men cannot pass on the disease to their offspring.

Norrie disease and other NDP related diseases are diagnosed with the combination of clinical findings and molecular genetic testing. Molecular genetic testing identifies the mutations that cause the disease in about 85% of affected males. Clinical diagnoses rely on ocular findings. Norrie disease is diagnosed when grayish-yellow fibrovascular masses are found behind the eye from birth through three months. Doctors also look for progression of the disease from three months through 8–10 years of age. Some of these progressions include cataracts, iris atrophy, shallowing of anterior chamber, and shrinking of the globe. By this point, people with the condition either have only light perception or no vision at all.

Molecular genetic testing is used for more than an initial diagnosis. It is used to confirm diagnostic testing, for carrier testing females, prenatal diagnosis, and preimplantation genetic diagnosis. There are three types of clinical molecular genetic testing. In approximately 85% of males, mis-sense and splice mutations of the NDP gene and partial or whole gene deletions are detected using sequence analysis. Deletion/duplication analysis can be used to detect the 15% of mutations that are submicroscopic deletions. This is also used when testing for carrier females. The last testing used is linkage analysis, which is used when the first two are unavailable. Linkage analysis is also recommended for those families who have more than one member affected by the disease.

On MRI the retinal dysplasia that occurs with the syndrome can be indistinguishable from persistent hyperplastic primary vitreous, or the dysplasia of trisomy 13 and Walker–Warburg syndrome.

Cornea plana 2 (CNA2) is an extremely rare congenital hereditary deformity of the eye surface, leading to severe decrease in corneal curvature. There is evidence that cornea plana 2 is caused by mutations in KERA gene encoding "keratocan".

While choroideremia is an ideal candidate for gene therapy there are other potential therapies that could restore vision after it has been lost later in life. Foremost of these is stem cell therapy. A clinical trial published in 2014 found that a subretinal injection of human embryonic stem cells in patients with age-related macular degeneration and Stargardt disease was safe and improved vision in most patients. Out of 18 patients, vision improved in 10, improved or remained the same in 7, and decreased in 1 patient, while no improvement was seen in the untreated eyes. The study found "no evidence of adverse proliferation, rejection, or serious ocular or systemic safety issues related to the transplanted tissue." A 2015 study used CRISPR/Cas9 to repair mutations in patient-derived induced pluripotent stem cells that cause X-linked retinitis pigmentosa. This study suggests that a patient's own repaired cells could be used for therapy, reducing the risk of immune rejection and ethical issues that come with the use of embryonic stem cells.

The most recognized cause of a toxic optic neuropathy is methanol intoxication. This can be a life-threatening event that normally accidentally occurs when the victim mistook, or substituted, methanol for ethyl alcohol. Blindness can occur with drinking as little as an ounce of methanol, but this can be counteracted by concurrent drinking of ethyl alcohol. The patient initially has nausea and vomiting, followed by respiratory distress, headache, and visual loss 18–48 hours after consumption. Without treatment, patients can go blind, and their pupils will dilate and stop reacting to light.

- Ethylene glycol, a component of automobile antifreeze, is a poison that is toxic to the whole body including the optic nerve. Consumption can be fatal, or recovery can occur with permanent neurologic and ophthalmologic deficits. While visual loss is not very common, increased intracranial pressure can cause bilateral optic disc swelling from cerebral edema. A clue to the cause of intoxication is the presence of oxalate crystals in the urine. Like methanol intoxication, treatment is ethanol consumption.

- Ethambutol, a drug commonly used to treat tuberculosis, is notorious for causing toxic optic neuropathy. Patients with vision loss from ethambutol toxicity lose vision in both eyes equally. This initially presents with problems with colors (dyschromatopsia) and can leave central visual deficits. If vision loss occurs while using ethambutol, it would be best to discontinue this medication under a doctor’s supervision. Vision can improve slowly after discontinuing ethambutol but rarely returns to baseline.

- Amiodarone is an antiarrhythmic medication commonly used for abnormal heart rhythms (atrial or ventricular tachyarrythmias). Most patients on this medication get corneal epithelial deposits, but this medication has also been controversially associated with NAION. Patients on amiodarone with new visual symptoms should be evaluated by an ophthalmologist.

- Tobacco exposure, most commonly through pipe and cigar smoking, can cause an optic neuropathy. Middle-aged or elderly men are often affected and present with painless, slowly progressive, color distortion and visual loss in both eyes. The mechanism is unclear, but this has been reported to be more common in individuals who are already suffering from malnutrition.

Congenital heterochromia is usually inherited as an autosomal dominant trait.

Patients with optic disc drusen should be monitored periodically for ophthalmoscopy, Snellen acuity, contrast sensitivity, color vision, intraocular pressure and threshold visual fields. For those with visual field defects optical coherence tomography has been recommended for follow up of nerve fiber layer thickness. Associated conditions such as angioid streaks and retinitis pigmentosa should be screened for. Both the severity of optic disc drusen and the degree of intraocular pressure elevation have been associated with visual field loss. There is no widely accepted treatment for ODD, although some clinicians will prescribe eye drops designed to decrease the intra-ocular pressure and theoretically relieve mechanical stress on fibers of the optic disc. Rarely choroidal neovascular membranes may develop adjacent to the optic disc threatening bleeding and retinal scarring. Laser treatment or photodynamic therapy or other evolving therapies may prevent this complication.