Many cases are asymptomatic, however patients many have decreased vision, glare, monocular diplopia or polyopia, and noticeable iris changes [2,6]. On exam patients have normal to decreased visual acuity, and a “beaten metal appearance” of the corneal endothelium, corneal edema, increased intraocular pressure, peripheral anterior synechiae, and iris changes [1,2,6].

Persistent tunica vasculosa lentis is a congenital ocular anomaly. It is a form of persistent hyperplastic primary vitreous (PHPV).

It is a developmental disorder of the vitreous. It is usually unilateral and first noticed in the neonatal period. It may be associated with micropthalmos, cataracts, and increased intraocular pressure. Elongated ciliary processes are visible through the dilated pupil. A USG B-scan confirms diagnosis in the presence of a cataract.

Iridocorneal Endothelial (ICE) syndromes are a spectrum of diseases characteriezed by slowly progressive abnormalities of the corneal endothelium and features including corneal edema, iris distortion, and secondary angle-closure glaucoma. [1,2,4] ICE syndromes are predominantly unilateral and nonhereditary [1,2,4]. The condition occurs in predominantly middle-aged women [1,3,4].

This condition is often associated with diabetes in advanced proliferative diabetic retinopathy. Other conditions causing rubeosis iridis include central retinal vein occlusion, ocular ischemic syndrome, and chronic retinal detachment.

Rubeosis iridis, also called neovascularization of the iris (NVI), is a medical condition of the iris of the eye in which new abnormal blood vessels (formed by neovascularization) are found on the surface of the iris.

The primary symptom is pupillary distortion (changing of the size or shape of the pupil). Distortion can occur in any segment of the iris. One part of the iris is pulled to a peak, and then returns to normal after the episode. Other symptoms may include blurred vision, abnormal periocular sensations (unusual feelings around the eyes), migraines, and feelings of a chilled face. Some patients who demonstrate tadpole pupil symptoms also experienced Horner’s syndrome or Adie’s tonic pupil

Tadpole pupil symptoms occur in episodes. Episodes are generally brief and less than 5 minutes, however, some episodes have been reported to last anywhere from 3 to 15 minutes. The episodes can occur multiple times a day for days, weeks, or months.

Studies show that a majority of those experiencing tadpole pupil are younger women from an age range of 24 to 48 years old, with no apparent health problems. Although women generally have the tadpole pupil, men are not unaffected by this disease and some have been reported to experience the symptoms.

This condition is usually unilateral, and its symptoms vary from none to mild blurring and discomfort. Signs include diffuse iris atrophy and small white keratic precipitates (deposits on the inner surface of the cornea), cells presenting in the anterior chamber as well as the anterior vitreous. Glaucoma and cataract occur frequently.

Lens subluxation is also seen in dogs and is characterized by a partial displacement of the lens. It can be recognized by trembling of the iris (iridodonesis) or lens (phacodonesis) and the presence of an aphakic crescent (an area of the pupil where the lens is absent). Other signs of lens subluxation include mild conjunctival redness, vitreous humour degeneration, prolapse of the vitreous into the anterior chamber, and an increase or decrease of anterior chamber depth. Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma. A nonsurgical alternative involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber.

Plateau iris is a medical condition of the eye resulting from pushing of peripheral part of iris forward, by the large or anteriorly placed ciliary body causing angle closer glaucoma.

http://image.slidesharecdn.com/gonioscopy-140211072931-phpapp01/95/gonioscopy-70-638.jpg?cb=1392103893

this configuration is usually corrected by iridectomy.

if the glaucoma persists even after iridectomy then it is called plateau iris syndrome, this is managed by miotics or laser peripheral iridoplasty

With anterior lens luxation, the lens pushes into the iris or actually enters the anterior chamber of the eye. This can cause glaucoma, uveitis, or damage to the cornea. Uveitis (inflammation of the eye) causes the pupil to constrict (miosis) and trap the lens in the anterior chamber, leading to an obstruction of outflow of aqueous humour and subsequent increase in ocular pressure (glaucoma). Better prognosis is valued in lens replacement surgery (retained vision and normal intraocular pressure) when it is performed before the onset of secondary glaucoma. Glaucoma secondary to anterior lens luxation is less common in cats than dogs due to their naturally deeper anterior chamber and the liquification of the vitreous humour secondary to chronic inflammation. Anterior lens luxation is considered to be an ophthalmological emergency.

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).

The effects a coloboma has on the vision can be mild or more severe depending on the size and location of the gap. If, for example, only a small part of the iris is missing, vision may be normal, whereas if a large part of the retina or optic nerve is missing, vision may be poor and a large part of the visual field may be missing. This is more likely to cause problems with mobility if the lower visual field is absent. Other conditions can be associated with a coloboma. Sometimes, the eye may be reduced in size, a condition called microphthalmia. Glaucoma, nystagmus, scotoma, or strabismus may also occur.

CPEO is a slowly progressing disease. It may begin at any age and progresses over a period of 5–15 years. The first presenting symptom of ptosis is often unnoticed by the patient until the lids droop to the point of producing a visual field defect. Often, patients will tilt the head backwards to adjust for the slowly progressing ptosis of the lids. In addition, as the ptosis becomes complete, the patients will use the frontalis (forehead) muscle to help elevate the lids. The ptosis is typically bilateral, but may be unilateral for a period of months to years before the fellow lid becomes involved.

Ophthalmoplegia or the inability or difficulty to move the eye is usually symmetrical. As such, double vision is sometimes a complaint of these patients. The progressive ophthalmoplegia is often unnoticed till decreased ocular motility limits peripheral vision. Often someone else will point out the ocular disturbance to the patient. Patients will move their heads to adjust for the loss of peripheral vision caused by inability to abduct or adduct the eye. All directions of gaze are affected; however, downward gaze appears to be best spared. This is in contrast to progressive supranuclear palsy (PSP), which typically affects vertical gaze and spares horizontal gaze.

Fuchs heterochromic iridocyclitis (FHI) is a chronic unilateral uveitis appearing with the triad of heterochromia, predisposition to cataract and glaucoma, and keratitic precipitates on the posterior corneal surface. Patients are often asymptomatic and the disease is often discovered through investigation of the cause of the heterochromia or cataract. Neovascularisation (growth of new abnormal vessels) is possible and any eye surgery, such as cataract surgery, can cause bleeding from the fragile vessels in the atrophic iris causing accumulation of blood in anterior chamber of the eye, also known as hyphema.

The eye is made up of the sclera, the iris, and the pupil, a black hole located at the center of the eye with the main function of allowing light to pass to the retina. Due to certain muscle spasms in the eye, the pupil can resemble a tadpole, which consists of a circular body, no arms or legs, and a tail.

When the pupil takes on the shape of a tadpole, the condition is called tadpole pupil. Tadpole pupil, also known as episodic segmental iris mydriasis, is an ocular condition where the muscles of the iris begin to spasm causing the elongation, or lengthening, of parts of the iris. These spasms can affect any segment, or portion, of the iris and involve the iris dilator muscle. Contractions of the iris dilator muscle, a smooth muscle of the eye running radially in the iris, can cause irregular distortion of the pupil, thus making the pupil look tadpole shaped and giving this condition its name. Episodic segmental iris mydriasis was first described and termed “tadpole pupil” in 1912 by HS Thompson

Weakness of extraocular muscle groups including, the orbicularis oculi muscle as well as facial and limb muscles may be present in up to 25% of patients with CPEO. As a result of the orbicularis oculi weakness, patients may suffer from exposure keratopathy (damage to cornea) from the inability to close the eyes tightly. Frontalis muscle weakness may exacerbate the ptotic lids with the inability to compensate for the ptosis. Facial muscles may be involved which lead to atrophy of facial muscle groups producing a thin, expressionless face with some having difficulty with chewing. Neck, shoulder and extremity weakness with atrophy may affect some patients and can be mild or severe.

Mild visual impairment was seen in 95% of patients that were evaluated using the Visual Function Index (VF-14).

The ciliary muscles that control the lens shape and the iris muscles are often unaffected by CPEO.

Additional symptoms are variable, and may include exercise intolerance, cataracts, hearing loss, sensory axonal neuropathy, ataxia, clinical depression, hypogonadism, and parkinsonism.

Kearns–Sayre syndrome is characterized by onset before 15 years of age of CPEO, heart block and pigmentary retinopathy.

Late congenital syphilitic oculopathy is a disease of the eye, a manifestation of late congenital syphilis. It can appear as:

- Interstitial keratitis – this commonly appears between ages 6 and 12. Symptoms include lacrimation and photophobia. Pathological vascularization of the cornea cause it to turn pink or salmon colored. 90% of cases affect both eyes.

- Episcleritis or scleritis – nodules appear in or overlying the sclera (white of eye)

- Iritis or iris papules – vascular infiltration of the iris causes rosy color change and yellow/red nodules.

- Chorioretinitis, papillitis, retinal vasculitis – retinal changes can resemble retinitis pigmentosa.

- Exudative retinal detachment

Congenital syphilis is categorized by the age of the child. Early congenital syphilis occurs in children under 2 years old, and late congenital syphilis in children at or greater than 2 years old. Manifestations of late congenital syphilis are similar to those of secondary syphilis and tertiary syphilis in adults.

Other ocular malformations that include coloboma or are related to it:

- CHARGE syndrome, a term that came into use as an acronym for the set of unusual congenital features seen in a number of newborn children. The letters stand for: coloboma of the eye, heart defects, atresia of the nasal choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness. Although these features are no longer used in making a diagnosis, the name has remained.

- Cat eye syndrome, caused by the short arm (p) and a small section of the long arm (q) of human chromosome 22 being present three (trisomic) or four times (tetrasomic) instead of the usual two times. The term "cat eye" was coined because of the particular appearance of the vertical colobomas in the eyes of some patients.

- Patau syndrome (trisomy 13), a chromosomal abnormality that can cause a number of deformities, some of which include structural eye defects, including microphthalmia, Peters anomaly, cataract, iris and/or fundus coloboma, retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia.

- Treacher Collins syndrome, autosomal dominant syndrome caused by mutation of "TCOF1". Coloboma is part of a set of characteristic facies that features craniofacial malformations, such as downslanting eyes, ear anomalies, or hypoplasia of zygomatic bone and jaw (micrognathia).

Those with ocular ischemic syndrome are typically between the ages of 50 and 80 (patients over 65) ; twice as many men as women are affected. More than 90% of those presenting with the condition have vision loss. Patients may report a dull, radiating ache over the eye and eyebrow. Those with ocular ischemic syndrome may also present with a history of other systemic diseases including arterial hypertension, diabetes mellitus, coronary artery disease, previous stroke, and hemodialysis.

The condition presents with visual loss secondary to hypoperfusion of the eye structures. The patient presents with intractable pain or ocular angina. On dilated examination, there may be blot retinal hemorrhages along with dilated and beaded retinal veins. The ocular perfusion pressure is decreased.

The corneal layers show edema and striae. There is mild anterior uveitis. A cherry-red spot may be seen in the macula, along with cotton-wool spots elsewhere, due to retinal nerve fiber layer hemorrhages. The retinal arteries may show spontaneous pulsations.

Asteroid hyalosis is a degenerative condition of the eye involving small white opacities in the vitreous humor. It is known to occur in humans, dogs, cats, horses, and chinchillas. Clinically, these opacities are quite refractile, giving the appearance of stars (or asteroids) shining in the night sky—except that ocular asteroids are often quite mobile. Ocular asteroids must be distinguished from the more common typical vitreous floaters, which are usually fibrillar or cellular condensates. The cause of asteroid hyalosis is unknown, but it has been associated with diabetes mellitus, hypertension, hypercholesterolemia, and, in certain animals, tumors of the ciliary body. In dogs, asteroid hyalosis is considered to be an age related change. The asteroid bodies are made up of hydroxylapatite, which in turn consists of calcium and phosphates or phospholipids. While asteroid hyalosis does not usually severely affect vision, the floating opacities can be quite annoying, and may interfere significantly with visualization and testing of the retina. While treatment of asteroid hyalosis is usually unnecessary, vitrectomy may occasionally be indicated, for both diagnostic and therapeutic purposes.

The most prominent symptoms of Norrie disease are ocular. The first visible finding is leukocoria, a grayish-yellow pupillary reflex that originates from a mass of unorganized tissue behind the lens. This material, which possibly includes an already detached retina, may be confused with a tumor and thus is termed pseudoglioma. However, an affected baby may have a normally sized eye globe and inconspicuous iris, anterior chamber, cornea and intraocular pressure.

Over the first few months of life, complete or partial retinal detachment evolves. From infancy through childhood, the patient may undergo progressive changes in the disease. These progressions include the formation of cataracts, deterioration of the iris with adhesions forming between the iris and the lens or the cornea, and shallowing of the anterior chamber which may increase intraocular pressure, causing eye pain. As the situation worsens, there is corneal opacification, where the cornea becomes opaque, and band keratopathy. Intraocular pressure is lost and the globe shrinks. In the last stage of Norrie disease, the globes appear small and sunken in (phthisis bulbi) and the cornea appears to be milky .

Norrie disease can also have cognitive and behavioral symptoms. Developmental delay or learning difficulties are present in about 30 to 50% of males who have Norrie disease. Psychotic-like features and poorly characterized behavior abnormalities may also be present. Auditory symptoms are common with Norrie disease. Progressive hearing loss starts in early childhood for a majority of males with the condition. Early hearing loss is sensorineural, mild and asymmetric. By adolescence, high-frequency hearing loss begins to appear. Hearing loss is severe, symmetric, and broad-spectrum by the age of 35. However, studies show that while the hearing loss is deteriorating, the ability to speak well is highly preserved. The slowly progressing hearing loss is more problematic to adjust to than the congenital blindness for most people with Norrie disease.

Patients may have no specific symptoms. In some cases, patients may complain of lessened visual acuity or changes in their perceived visual field, and such changes may be secondary to or different from symptoms normally associated with cataracts or glaucoma.

PEX is characterized by tiny microscopic white or grey granular flakes which are clumps of proteins within the eye which look somewhat like dandruff when seen through a microscope and which are released by cells. The abnormal flakes, sometimes compared to amyloid-like material, are visible during an examination of the lens of an eye by an ophthalmologist or optometrist, which is the usual diagnosis. The white fluffy material is seen in many tissues both ocular and extraocular, such as in the anterior chamber structures, trabecular meshwork, central disc, zonular fibres, anterior hyaloid membrane, pupillary and anterior iris, trabecula, and occasionally the cornea. The flakes are widespread. One report suggested that the granular flakes were from abnormalities of the basement membrane in epithelial cells, and that they were distributed widely throughout the body and not just within structures of the eye. There is some research suggesting that the material may be produced in the iris pigment epithelium, ciliary epithelium, or the peripheral anterior lens epithelium. A similar report suggests that the proteins come from the lens, iris, and other parts of the eye. A report in 2010 found indications of an abnormal ocular surface in PEX patients, discovered by an eye staining method known as rose bengal.

PEX can become problematic when the flakes become enmeshed in a "spongy area" known as the trabecular meshwork and block its normal functioning, and may interact with degenerative changes in the Schlemm's canal and the juxtacanalicular area. The blockage leads to greater-than-normal elevated intraocular pressure which, in turn, can damage the optic nerve. The eye produces a clear fluid called the aqueous humor which subsequently drains such that there is a constant level of safe pressure within the eye, but glaucoma can result if this normal outflow of fluid is blocked. Glaucoma is an umbrella term indicating ailments which damage the neural cable from the eye to the brain called the optic nerve, and which can lead to a loss of vision. In most cases of glaucoma, typically called "primary open-angle glaucoma", the outflow does not happen normally but doctors can not see what is causing the blockage; with PEX, however, the flakes are believed to be a cause of the blockage. PEX flakes by themselves do not directly "cause" glaucoma, but can cause glaucoma indirectly by blocking the outflow of aqueous humor, which leads to higher intraocular pressure, and this can cause glaucoma. PEX has been known to cause a weakening of structures within the eye which help hold the eye's lens in place, called lens zonules.

Leukocoria (also leukokoria or white pupillary reflex) is an abnormal white reflection from the retina of the eye. Leukocoria resembles eyeshine, but leukocoria can occur in humans and other animals that lack eyeshine because their retina lacks a "tapetum lucidum".

Leukocoria is a medical sign for a number of conditions, including Coats disease, congenital cataract, corneal scarring, melanoma of the ciliary body, Norrie disease, ocular toxocariasis, persistence of the tunica vasculosa lentis (PFV/PHPV), retinoblastoma, and retrolental fibroplasia.

Because of the potentially life-threatening nature of retinoblastoma, a cancer, that condition is usually considered in the evaluation of leukocoria. In some rare cases (1%) the leukocoria is caused by Coats' disease (leaking retinal vessels).

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 experience of amaurosis fugax is classically described as a temporary loss of vision in one or both eyes that appears as a black "curtain coming down vertically into the field of vision in one eye;" however, this altitudinal visual loss is relatively uncommon. In one study, only 23.8 percent of patients with transient monocular vision loss experienced the classic "curtain" or "shade" descending over their vision. Other descriptions of this experience include a monocular blindness, dimming, fogging, or blurring. Total or sectorial vision loss typically lasts only a few seconds, but may last minutes or even hours. Duration depends on the cause of the vision loss. Obscured vision due to papilledema may last only seconds, while a severely atherosclerotic carotid artery may be associated with a duration of one to ten minutes. Certainly, additional symptoms may be present with the amaurosis fugax, and those findings will depend on the cause of the transient monocular vision loss.