A rhegmatogenous retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms:

- flashes of light (photopsia) – very brief in the extreme peripheral (outside of center) part of vision

- a sudden dramatic increase in the number of floaters

- a ring of floaters or hairs just to the temporal (skull) side of the central vision

Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms:

- a dense shadow that starts in the peripheral vision and slowly progresses towards the central vision

- the impression that a veil or curtain was drawn over the field of vision

- straight lines (scale, edge of the wall, road, etc.) that suddenly appear curved (positive Amsler grid test)

- central visual loss

In the event of an appearance of sudden flashes of light or floaters, an eye doctor needs to be consulted immediately. A shower of floaters or any loss of vision, too, is a medical emergency.

Signs and symptoms vary depending on the type of cataract, though considerable overlap occurs. People with nuclear sclerotic or brunescent cataracts often notice a reduction of vision. Those with posterior subcapsular cataracts usually complain of glare as their major symptom.

The severity of cataract formation, assuming no other eye disease is present, is judged primarily by a visual acuity test. The appropriateness of surgery depends on a patient's particular functional and visual needs and other risk factors, all of which may vary widely.

Seeing rainbows around lights, especially at night, usually indicates swelling of the cornea. This may occur from a variety of causes which are discussed under Corneal Edema. Cataract can sometimes cause this also.

Colour vision is perceived mainly by the macula, which is the central vision portion of the retina. Thus any disorder affecting the macula may cause a disturbance in color vision. However, about 8% of males and 0.5% of females have some version of "colour blindness" from birth. Usually this is a genetically inherited trait, and is of the "red-green confusion" variety. The reds, browns, olives, and gold may be confused. Purple may be confused with blue, and pastel pinks, oranges, yellows, and greens look similar. Usually both eyes are affected equally.

There are many obscure macular retinal disorders that can lead to a loss of colour vision, and many of these syndromes are inherited as well. There may also be a problem with a generalized loss of vision with these problems as well. Other retinal problems can lead to a temporary disturbance of colour vision, such as Central serous chorioretinopathy, Macular Edema of different causes, and Macular Degeneration.

Certain types of cataract can gradually affect the colour vision, but this is usually not noticed until one cataract is removed. The cataract seems to filter out the colour blue, and everything seems more blue after cataract extraction. Optic nerve disorders such as Optic Neuritis can greatly affect colour vision, with colours seeming washed out during or after an episode.

The term congenital refers to a condition present from birth (not acquired) and amaurosis refers to a loss of vision "not" associated with a lesion. However, beyond these general descriptions, the presentation of LCA can vary, because it is associated with multiple genes.

LCA is typically characterized by nystagmus, sluggish or absent pupillary responses, and severe vision loss or blindness.

Congenital cataracts refers to a lens opacity present at birth. Congenital cataracts cover a broad spectrum of severity: whereas some lens opacities do not progress and are visually insignificant, others can produce profound visual impairment.

Congenital cataracts may be unilateral or bilateral. They can be classified by morphology, presumed or defined genetic cause, presence of specific metabolic disorders, or associated ocular anomalies or systemic findings.

Congenital cataracts occur in a variety of morphologic configurations, including lamellar, polar, sutural, coronary, cerulean, nuclear, capsular, complete, membranous.

Distortion of vision refers to straight lines not appearing straight, but instead bent, crooked, or wavy. Usually this is caused by distortion of the retina itself. This distortion can herald a loss of vision in macular degeneration, so anyone with distorted vision should seek medical attention by an ophthalmologist promptly. Other conditions leading to swelling of the retina can cause this distortion, such as macular edema and central serous chorioretinopathy.

An Amsler grid can be supplied by an ophthalmologist so that the vision can be monitored for distortion in people who may be predisposed to this problem.

Tunnel vision implies that the peripheral vision, or side vision, is lost, while the central vision remains. Thus, the vision is like looking through a tunnel, or through a paper towel roll. Some disorders that can cause this include:

Glaucoma - severe glaucoma can result in loss of nearly all of the peripheral vision, with a small island of central vision remaining. Sometimes even this island of vision can be lost as well.

Retinitis pigmentosa - This is usually a hereditary disorder which can be part of numerous syndromes. It is more common in males. The peripheral retina develops pigmentary deposits, and the peripheral vision gradually becomes worse and worse. The central vision can be affected eventually as well. People with this problem may have trouble getting around in the dark. Cataract can be a complication as well. There is no known treatment for this disorder, and supplements of Vitamin A have not been proven to help.

Punctate Inner Choroidopathy - This condition is where vessels gro (( material is missing ))

Stroke - a stroke involving both sides of the visual part of the brain may wipe out nearly all of the peripheral vision. Fortunately, this is a very rare occurrence

Acorea or fibrous occlusion of the pupil, microphthalmia and cataracts are present in both eyes. Microcornea and iridocorneal dysgenesis also occur. The retina and optic disc are normal.

Irvine–Gass syndrome, pseudophakic cystoid macular edema or postcataract CME is one of the most common causes of visual loss after cataract surgery. The syndrome is named in honor of S. Rodman Irvine and J. Donald M. Gass.

The incidence is more common in older types of cataract surgery, where postcataract CME could occur in 20–60% of patients, but with modern cataract surgery, incidence of Irvine–Gass syndrome have reduced significantly.

Replacement of the lens as treatment for cataract can cause pseudophakic macular edema. (‘pseudophakia’ means ‘replacement lens’) this could occur as the surgery involved sometimes irritates the retina (and other parts of the eye) causing the capillaries in the retina to dilate and leak fluid into the retina. This is less common today with modern lens replacement techniques

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.

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

Signs and symptoms of macular degeneration include:

- Visual symptoms

- Distorted vision in the form of metamorphopsia, in which a grid of straight lines appears wavy and parts of the grid may appear blank: Patients often first notice this when looking at things like miniblinds in their home or telephone poles while driving. There may also be central scotomas, shadows or missing areas of vision

- Slow recovery of visual function after exposure to bright light (photostress test)

- Visual acuity drastically decreasing (two levels or more), e.g.: 20/20 to 20/80

- Blurred vision: Those with nonexudative macular degeneration may be asymptomatic or notice a gradual loss of central vision, whereas those with exudative macular degeneration often notice a rapid onset of vision loss (often caused by leakage and bleeding of abnormal blood vessels).

- Trouble discerning colors, specifically dark ones from dark ones and light ones from light ones

- A loss in contrast sensitivity

Macular degeneration by itself will not lead to total blindness. For that matter, only a very small number of people with visual impairment are totally blind. In almost all cases, some vision remains, mainly peripheral. Other complicating conditions may possibly lead to such an acute condition (severe stroke or trauma, untreated glaucoma, etc.), but few macular degeneration patients experience total visual loss.

The area of the macula comprises only about 2.1% of the retina, and the remaining 97.9% (the peripheral field) remains unaffected by the disease. Even though the macula provides such a small fraction of the visual field, almost half of the visual cortex is devoted to processing macular information.

The loss of central vision profoundly affects visual functioning. It is quite difficult, for example, to read without central vision. Pictures that attempt to depict the central visual loss of macular degeneration with a black spot do not really do justice to the devastating nature of the visual loss. This can be demonstrated by printing letters six inches high on a piece of paper and attempting to identify them while looking straight ahead and holding the paper slightly to the side. Most people find this difficult to do.

Nearly every person who undergoes a vitrectomy—without ever having had cataract surgery—will experience progression of nuclear sclerosis after the operation. This may be because the native vitreous humor is different to the solutions used to replace the vitreous (vitreous substitutes), such as BSS Plus. This may also be because the native vitreous humour contains ascorbic acid which helps neutralize oxidative damage to the lens and because traditional vitreous substitutes do not contain ascorbic acid. As such, for phakic patients requiring a vitrectomy it is becoming increasingly common for ophthalmologists to offer the vitrectomy with a combined prophylactic cataract surgery procedure to prophylactically prevent cataract formation.

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.

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.

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.

Retinal detachment is a disorder of the eye in which the retina separates from the layer underneath. Symptoms include an increase in the number of floaters, flashes of light, and worsening of the outer part of the visual field. This may be described as a curtain over part of the field of vision. In about 7% of cases both eyes are affected. Without treatment permanent loss of vision may occur.

The mechanism most commonly involves a break in the retina that then allows the fluid in the eye to get behind the retina. A break in the retina can occur from a posterior vitreous detachment, injury to the eye, or inflammation of the eye. Other risk factors include being short sighted and previous cataract surgery. Retinal detachments also rarely occur due to a choroidal tumor. Diagnosis is by either looking at the back of the eye with an ophthalmoscope or by ultrasound.

In those with a retinal tear, efforts to prevent it becoming a detachment include cryotherapy using a cold probe or photocoagulation using a laser. Treatment of retinal detachment should be carried out in a timely manner. This may include scleral buckling where silicone is sutured to the outside of the eye, pneumatic retinopexy where gas is injected into the eye, or vitrectomy where the vitreous is partly removed and replaced with either gas or oil.

Retinal detachments affect between 0.6 and 1.8 people per 10,000 per year. About 0.3% of people are affected at some point in their life. It is most common in people who are in their 60s or 70s. Males are more often affected than females. The long term outcomes depend on the duration of the detachment and whether the macula was detached. If treated before the macula detaches outcomes are generally good.

When this occurs there is a characteristic pattern of symptoms:

- Flashes of light (photopsia)

- A sudden dramatic increase in the number of floaters

- A ring of floaters or hairs just to the temporal side of the central vision

As a posterior vitreous detachment proceeds, adherent vitreous membrane may pull on the retina. While there are no pain fibers in the retina, vitreous traction may stimulate the retina, with resultant flashes that can look like a perfect circle.

If a retinal vessel is torn, the leakage of blood into the vitreous cavity is often perceived as a "shower" of floaters. Retinal vessels may tear in association with a retinal tear, or occasionally without the retina being torn.

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.

Floaters are deposits of various size, shape, consistency, refractive index, and motility within the eye's vitreous humour, which is normally transparent. At a young age, the vitreous is

transparent, but as one ages, imperfections gradually develop. The common type of floater, which is present in most persons' eyes, is due to degenerative changes of the vitreous humour. The perception of floaters is known as "myodesopsia", or less commonly as "myodaeopsia", "myiodeopsia", or "myiodesopsia". They are also called "Muscae volitantes" (Latin: "flying flies"), or "mouches volantes" (from the French). Floaters are visible because of the shadows they cast on the retina or refraction of the light that passes through them, and can appear alone or together with several others in one's visual field. They may appear as spots, threads, or fragments of cobwebs, which float slowly before the observer's eyes. As these objects exist within the eye itself, they are not optical illusions but are entoptic phenomena. They are not to be confused with visual snow, although these two conditions may co-exist.

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.

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).

The risk of retinal detachment is greatest in the first 6 weeks following a vitreous detachment, but can occur over 3 months after the event.

The risk of retinal tears and detachment associated with vitreous detachment is higher in patients with myopic retinal degeneration, lattice degeneration, and a familial or personal history of previous retinal tears/detachment.

Leber's congenital amaurosis (LCA) is a rare inherited eye disease that appears at birth or in the first few months of life.

One form of LCA was successfully treated with gene therapy in 2008.

It affects about 1 in 40,000 newborns. LCA was first described by Theodor Leber in the 19th century. It should not be confused with Leber's hereditary optic neuropathy, which is a different disease also described by Theodor Leber.

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).