The most extensive epidemiological survey on this congenital malformation has been carried out by Dharmasena et al and using English National Hospital Episode Statistics, they calculated the annual incidence of anophthalmia, microphthalmia and congenital malformations of orbit/lacrimal apparatus from 1999 to 2011. According to this study the annual incidence of congenital microphthalmia in the United Kingdom was 10.8 (8.2 to 13.5) in 1999 and 10.0 (7.6 to 12.4) in 2011.

It has been suggested that the disease follows a x-linked pattern of inheritance though studies done on this particular disease are few.

Most people with the disease need laser repairs to the retina, and about 60 per cent need further surgery.

There is no known cure for this syndrome. Patients usually need ophthalmic surgery and may also need dental surgery

Genetic counseling and screening of the mother's relatives is recommended.

This syndrome is due to mutations in the Nance Horan gene (NHS) which is located on the short arm of the X chromosome (Xp22.13).

Microphthalmia in newborns is sometimes associated with fetal alcohol syndrome or infections during pregnancy, particularly herpes simplex virus, rubella and cytomegalovirus (CMV), but the evidence is inconclusive. Genetic causes of microphthalmia include chromosomal abnormalities (Trisomy 13 (Patau syndrome), Triploid Syndrome, 13q deletion syndrome, and Wolf-Hirschhorn Syndrome) or monogenetic Mendelian disorders. The latter may be autosomal dominant, autosomal recessive or X linked.

The following genes have been implicated in microphthamia, many of which are transcription and regulatory factors:

How these genes result in the eye disorder is unknown but it has been postulated that interference with the process of eye growth after birth may be involved in contrast to anophthalmia (absence of eyeball) which originates much earlier during foetal development. SOX2 has been implicated in a substantial number (10-15%) of cases and in many other cases failure to develop the ocular lens often results in microphthamia. Microphthalmia-associated transcription factor (MITF) located on chromosome 14q32 is associated with one form of isolated microphthalmia (MCOP1. In mammals the failure of expression of the transcription factor, MITF (microphthalmia-associated transcription factor), in the pigmented retina prevents this structure from fully differentiating. This in turn causes a malformation of the choroid fissure of the eye, resulting in the drainage of vitreous humor fluid. Without this fluid, the eye fails to enlarge, thus the name microphthalmia.The gene encoding the microphthalmia-associated transcription factor (MITF) is a member of the basic helix-loop-helix-leucine zipper (bHLH-ZIP) family. Waardenburg syndrome type 2 (WS type 2) in humans is also a type of microphthalmia syndrome. Mutations in MITF gene are thought to be responsible for this syndrome. The human MITF gene is homologous to the mouse MITF gene (aka mouse mi or microphthalmia gene); mouse with mutations in this gene are hypopigmented in their fur. The identification of the genetics of WS type 2 owes a lot to observations of phenotypes of MITF mutant mice.

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)

Wagner's syndrome has for a long time been considered a synonym for Stickler's syndrome. However, since the gene that is responsible for Wagner disease (and Erosive Vitreoretinopathie) is known (2005), the confusion has ended. For Wagner disease is the Versican gene (VCAN) located at 5q14.3 is responsible.

For Stickler there are 4 genes are known to cause this syndrome: COL2A1 (75% of Stickler cases), COL11A1 (also Marshall syndrome), COL11A2 (non-ocular Stickler) and COL9A1 (recessive Stickler).

The gene involved helps regulate how the body makes collagen, a sort of chemical glue that holds tissues together in many parts of the body. This particular collagen gene only becomes active in the jelly-like material that fills the eyeball; in Wagner's disease this "vitreous" jelly grabs too tightly to the already weak retina and pulls it away.

The cataract-microcornea syndrome is the association of congenital cataract and microcornea.

Toxic optic neuropathy refers to the ingestion of a toxin or an adverse drug reaction that results in vision loss from optic nerve damage. Patients may report either a sudden loss of vision in both eyes, in the setting of an acute intoxication, or an insidious asymmetric loss of vision from an adverse drug reaction. The most important aspect of treatment is recognition and drug withdrawal.

Among the many causes of TON, the top 10 toxins include:

- Medications

- Ethambutol, rifampin, isoniazid, streptomycin (tuberculosis treatment)

- Linezolid (taken for bacterial infections, including pneumonia)

- Chloramphenicol (taken for serious infections not helped by other antibiotics)

- Isoretinoin (taken for severe acne that fails to respond to other treatments)

- Ciclosporin (widely used immunosuppressant)

- Acute Toxins

- Methanol (component of some moonshine, and some cleaning products)

- Ethylene glycol (present in anti-freeze and hydraulic brake fluid)

Metabolic disorders may also cause this version of disease. Systemic problems such as diabetes mellitus, kidney failure, and thyroid disease can cause optic neuropathy, which is likely through buildup of toxic substances within the body. In most cases, the cause of the toxic neuropathy impairs the tissue’s vascular supply or metabolism. It remains unknown as to why certain agents are toxic to the optic nerve while others are not and why particularly the papillomacular bundle gets affected.

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).

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.

Zonular cataract and nystagmus, also referred as Nystagmus with congenital zonular cataract is a rare congenital disease associated with Nystagmus and zonular cataract of the eye.

Congenital hereditary corneal dystrophy (CHED) is a form of corneal dystrophy which presents at birth.

TAA is an old term for a constellation of elements that can lead to a mitochondrial optic neuropathy. The classic patient is a man with a history of heavy alcohol and tobacco consumption. Respectively, this combines nutritional mitochondrial impairment, from vitamin deficiencies (folate and B-12) classically seen in alcoholics, with tobacco-derived products, such as cyanide and ROS. It has been suggested that the additive effect of the cyanide toxicity, ROS, and deficiencies of thiamine, riboflavin, pyridoxine, and b12 result in TAA.

In general, approximately one-third of congenital cataracts are a component of a more extensive syndrome or disease (e.g., cataract resulting from congenital rubella syndrome), one-third occur as an isolated inherited trait, and one-third result from undetermined causes. Metabolic diseases tend to be more commonly associated with bilateral cataracts.

A review from 2000 stated that life expectancy was reduced because of a tendency to develop cancer relatively early as well as deaths due to infections related to immunodeficiency.

CHED has two types:

- type I or the autosomal dominant form.

- type II or the autosomal recessive form is linked to mutations in SLC4A11 gene

There have been 30 cases of Marden-Walker Syndrome reported since 1966. The first case of this was in 1966 a female infant was diagnosed with blepharophimosis, joint contractures, arachnodactyly and growth development delay. She ended up passing at 3 months due to pneumonia.

Treatment with isotretinoin may induce substantial resolution of skin lesions, but the risk of secondary infection remains.

Rothmund–Thomson syndrome (RTS), also known as poikiloderma atrophicans with cataract or poikiloderma congenitale, is a rare autosomal recessive skin condition originally described by August von Rothmund (1830–1906) in 1868. Matthew Sydney Thomson (1894–1969) published further descriptions in 1936.

There have been several reported cases associated with osteosarcoma. A hereditary genetic basis, mutations in the DNA Helicase "RECQL4" gene, causing problems during initiation of DNA replication has been implicated in the syndrome

Genetic disorders may also be complex, multifactorial, or polygenic, meaning they are likely associated with the effects of multiple genes in combination with lifestyles and environmental factors. Multifactorial disorders include heart disease and diabetes. Although complex disorders often cluster in families, they do not have a clear-cut pattern of inheritance. This makes it difficult to determine a person’s risk of inheriting or passing on these disorders. Complex disorders are also difficult to study and treat, because the specific factors that cause most of these disorders have not yet been identified. Studies which aim to identify the cause of complex disorders can use several methodological approaches to determine genotype-phenotype associations. One method, the genotype-first approach, starts by identifying genetic variants within patients and then determining the associated clinical manifestations. This is opposed to the more traditional phenotype-first approach, and may identify causal factors that have previously been obscured by clinical heterogeneity, penetrance, and expressivity.

On a pedigree, polygenic diseases do tend to "run in families", but the inheritance does not fit simple patterns as with Mendelian diseases. But this does not mean that the genes cannot eventually be located and studied. There is also a strong environmental component to many of them (e.g., blood pressure).

- asthma

- autoimmune diseases such as multiple sclerosis

- cancers

- ciliopathies

- cleft palate

- diabetes

- heart disease

- hypertension

- inflammatory bowel disease

- intellectual disability

- mood disorder

- obesity

- refractive error

- infertility

Vici syndrome is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.

The hypothesis of autosomal recessive inheritance of Vici syndrome was strengthened in 2002 with the clinical description of two new cases, one brother and one sister, by Chiyonobu et al.

Vici syndrome, also called immunodeficiency with cleft lip/palate, cataract, hypopigmentation and absent corpus callosum, is a rare autosomal recessive congenital disorder characterized by albinism, agenesis of the corpus callosum, cataracts, cardiomyopathy, severe psychomotor retardation, seizures, immunodeficiency, and recurrent severe infections. To date about 50 cases have been reported.

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)