A recent study estimated that from 2002-2003 there were 27,152 injuries in the United States related to the wearing of eyeglasses. The same study concluded that sports-related injuries due to eyeglasses wear were more common in those under the age of 18 and that fall-related injuries due to eyeglasses wear were more common in those aged 65 or more. Although eyeglasses-related injuries do occur, prescription eyeglasses and non-prescription sunglasses have been found to "offer measurable protection which results in a lower incidence of severe eye injuries to those wearing [them]".

In India study conducted by Dr.Shukla, injuries are found more in n males(81%).This is true for both rural and urban population but in 0-10 age group, the difference between males and females is less.Females account for 28% injuries in this age group.However, in sedentary workers, farmers, labourers and industrial workers the male % is as high as 95%.Chemical injuries are the comments cause of bilateral injuries in the eye .

Multiple complications are known to occur following eye injury: corneal scarring, hyphema, iridodialysis, post-traumatic glaucoma, uveitis cataract, vitreous hemorrhage and retinal detachment. The complications risk is high with retinal tears, penetrating injuries and severe blunt trauma.

According to an American study nearly three in 10 children (28.4%) between the ages of five and 17 have astigmatism. A recent Brazilian study found that 34% of the students in one city were astigmatic. Regarding the prevalence in adults, a recent study in Bangladesh found that nearly 1 in 3 (32.4%) of those over the age of 30 had astigmatism.

A Polish study published in 2005 revealed "with-the-rule astigmatism" may lead to the onset of myopia.

A number of studies have found the prevalence of astigmatism increases with age.

Some of the adverse outcomes associated with intra-operative injuries include:

- Increased length of stay. This is due to ophthalmology consults required, associated infections and treatment.

- Increased costs. This is due to increased length of stay, cost of treating the complications.

- Pain and discomfort for the patient. Corneal abrasions are extremely painful for the patient and the treatment consists of drops and ointments applied in the eye which may cause further discomfort for the patient.

Scientists are studying different populations and relationships to try to learn more about the disease. They have found associations with different groups but it is not yet clear what the underlying factors are and how they affect different peoples around the world.

- Glaucoma patients. While PEX and glaucoma are believed to be related, there are cases of persons with PEX without glaucoma, and persons with glaucoma without PEX. Generally, a person with PEX is considered as having a risk of developing glaucoma, and vice versa. One study suggested that the PEX was present in 12% of glaucoma patients. Another found that PEX was present in 6% of an "open-angle glaucoma" group. Pseudoexfoliation syndrome is considered to be the most common of identifiable causes of glaucoma. If PEX is diagnosed without glaucoma, there is a high risk of a patient subsequently developing glaucoma.

- Country and region. Prevalence of PEX varies by geography. In Europe, differing levels of PEX were found; 5% in England, 6% in Norway, 4% in Germany, 1% in Greece, and 6% in France. One contrary report suggested that levels of PEX were higher among Greek people. One study of a county in Minnesota found that the prevalence of PEX was 25.9 cases per 100,000 people. It is reportedly high in northern European countries such as Norway, Sweden and Finland, as well as among the Sami people of northern Europe, and high among Arabic populations, but relatively rare among African Americans and Eskimos. In southern Africa, prevalence was found to be 19% of patients in a glaucoma clinic attending to persons of the Bantu tribes.

- Race. It varies considerably according to race.

- Gender. It affects women more than men. One report was that women were three times more likely than men to develop PEX.

- Age. Older persons are more likely to develop PEX. And persons younger than 50 are highly unlikely to have PEX. A study in Norway found that the prevalence of PEX of persons aged 50–59 was 0.4% while it was 7.9% for persons aged 80–89 years. If a person is going to develop PEX, the average age in which this will happen is between 69 and 75 years, according to the Norwegian study. A second corroborating report suggested that it happens primarily to people 70 and older. While older people are more likely to develop PEX, it is not seen as a "normal" part of aging.

- Other diseases. Sometimes PEX is associated with the development of medical problems other than merely glaucoma. There are conflicting reports about whether PEX is associated with problems of the heart or brain; one study suggested no correlations while other studies found statistical links with Alzheimer's disease, senile dementia, cerebral atrophy, chronic cerebral ischemia, stroke, transient ischemic attacks, heart disease, and hearing loss.

It is the name given to the localised bulge in limbal area, lined by the root of the iris. It results due to ectasia of weak scar tissue formed at the limbus, following healing of a perforating injury or a peripheral corneal ulcer. There may be associated secondary angle closure glaucoma, may cause progression of the bulge if not treated. Defective vision occurs due to marked corneal astigmatism. Treatment consists of localised staphylectomy under heavy doses of oral steroids.

As the name implies, it is the bulge of weak sclera lined by ciliary body, which occurs about 2–3 mm away from the limbus. Its common causes are thinning of sclera following perforating injury, scleritis & absolute glaucoma.

it is part of anterior staphyloma

Keratoconjunctivitis sicca is relatively common within the United States, especially so in older patients. Specifically, the persons most likely to be affected by dry eyes are those aged 40 or older. 10-20% of adults experience Keratoconjunctivitis sicca. Approximately 1 to 4 million adults (age 65-84) in the USA are effected.

While persons with autoimmune diseases have a high likelihood of having dry eyes, most persons with dry eyes do not have an autoimmune disease. Instances of Sjögren syndrome and keratoconjunctivitis sicca associated with it are present much more commonly in women, with a ratio of 9:1. In addition, milder forms of keratoconjunctivitis sicca also are more common in women. This is partly because hormonal changes, such as those that occur in pregnancy, menstruation, and menopause, can decrease tear production.

In areas of the world where malnutrition is common, vitamin A deficiency is a common cause. This is rare in the United States.

Racial predilections do not exist for this disease.

Young children with strabismus normally suppress the visual field of one eye (or part of it), whereas adults who develop strabismus normally do not suppress and therefore suffer from double vision (diplopia). This also means that adults (and older children) have a higher risk of post-operative diplopia after undergoing strabismus surgery than young children. Patients who have undergone strabismus surgery at a young age often have monofixation syndrome (with peripheral binocular fusion and a central suppression scotoma).

Terrier breeds are predisposed to lens luxation, and it is probably inherited in the Sealyham Terrier, Jack Russell Terrier, Wirehaired Fox Terrier, Rat Terrier, Teddy Roosevelt Terrier, Tibetan Terrier, Miniature Bull Terrier, Shar Pei, and Border Collie. The mode of inheritance in the Tibetan Terrier and Shar Pei is likely autosomal recessive. Labrador Retrievers and Australian Cattle Dogs are also predisposed.

Between 2 and 5% of the population in western countries have amblyopia. In the U.K., 90% of visual health appointments in the child are concerning amblyopia.

Depending on the chosen criterion for diagnosis, between 1 and 4% of the children have amblyopia.

Sympathetic ophthalmia is rare, affecting 0.2% to 0.5% of non-surgical eye wounds, and less than 0.01% of surgical penetrating eye wounds. There are no gender or racial differences in incidence of SO.

Many people of East Asian descent are prone to developing angle closure glaucoma due to shallower anterior chamber depths, with the majority of cases of glaucoma in this population consisting of some form of angle closure. Higher rates of glaucoma have also been reported for Inuit populations, compared to white populations, in Canada and Greenland.

With posterior lens luxation, the lens falls back into the vitreous humour and lies on the floor of the eye. This type causes fewer problems than anterior lens luxation, although glaucoma or ocular inflammation may occur. Surgery is used to treat dogs with significant symptoms. Removal of the lens before it moves to the anterior chamber may prevent secondary glaucoma.

Keratoconjunctivitis sicca is uncommon in cats. Most cases seem to be caused by chronic conjunctivitis, especially secondary to feline herpesvirus. Diagnosis, symptoms, and treatment are similar to those for dogs.

No clear evidence indicates vitamin deficiencies cause glaucoma in humans. It follows, then, that oral vitamin supplementation is not a recommended treatment for glaucoma. Caffeine increases intraocular pressure in those with glaucoma, but does not appear to affect normal individuals.

Strabismus can be seen in Down syndrome, Loeys-Dietz syndrome, cerebral palsy, and Edwards syndrome. The risk is increased among those with a family history of the condition.

A black eye, periorbital hematoma, or shiner, is bruising around the eye commonly due to an injury to the face rather than to the eye. The name is given due to the color of bruising. The so-called black eye is caused by bleeding beneath the skin and around the eye. Sometimes a black eye could get worse if not referring to a doctor after a few months, indicating a more extensive injury, even a skull fracture, particularly if the area around both eyes is bruised (raccoon eyes), or if there has been a prior head injury.

Although most black eye injuries are not serious, bleeding within the eye, called a hyphema, is serious and can reduce vision and damage the cornea. In some cases, abnormally high pressure inside the eyeball (ocular hypertension) can also result.

Exophthalmos is commonly found in dogs. It is seen in brachycephalic (short-nosed) dog breeds because of the shallow orbit. However, it can lead to keratitis secondary to exposure of the cornea. Exophthalmos is commonly seen in the Pug, Boston Terrier, Pekingese, and Shih Tzu.

It is a common result of head trauma and pressure exerted on the front of the neck too hard in dogs. In cats, eye proptosis is uncommon and is often accompanied by facial fractures.

About 40% of proptosed eyes retain vision after being replaced in the orbit, but in cats very few retain vision. Replacement of the eye requires general anesthesia. The eyelids are pulled outward, and the eye is gently pushed back into place. The eyelids are sewn together in a procedure known as tarsorrhaphy for about five days to keep the eye in place. Replaced eyes have a higher rate of keratoconjunctivitis sicca and keratitis and often require lifelong treatment. If the damage is severe, the eye is removed in a relatively simple surgery known as enucleation of the eye.

The prognosis for a replaced eye is determined by the extent of damage to the cornea and sclera, the presence or absence of a pupillary light reflex, and the presence of ruptured rectus muscles. The rectus muscles normally help hold the eye in place and direct eye movement. Rupture of more than two rectus muscles usually requires the eye to be removed, because significant blood vessel and nerve damage also usually occurs. Compared to brachycephalic breeds, dochilocephalic (long-nosed) breeds usually have more trauma to the eye and its surrounding structures, so the prognosis is worse .

The cause of pseudoexfoliation glaucoma is generally unknown.

PEX is generally believed to be a systemic disorder, possibly of the basement membrane of the eye. Researchers have noticed deposits of PEX material in various parts of the body, including in the skin, heart, lungs, liver, kidneys, and elsewhere. Nevertheless, what is puzzling is that PEX tends to happen in only one eye first, which scientists call "unilaterality", and in some cases, gradually afflicts the other eye, which is termed "bilaterality". According to this reasoning, if PEX were a systemic disorder, then both eyes should be affected at the same time, but they are not. There are contrasting reports about the extent and speed with which PEX moves from one eye to both eyes. According to one report, PEX develops in the second eye in 40% of cases. A contrasting report was that PEX can be found in both eyes in almost all situations if an electron microscope is used to examine the second eye, or if a biopsy of the conjunctiva was done, but that the extent of PEX is the second eye was much less than the first one. A different report suggested that two thirds of PEX patients had flakes in only one eye. In one long term study, patients with PEX in only one eye were studied, and it was found that over time, 13% progressed to having both eyes afflicted by PEX. Scientists believe that elevated levels of plasma homocysteine are a risk factor for cardiovascular disease, and two studies have found higher levels of plasma homocysteine in PEX patients, or elevated homocysteine concentrations in tear fluids produced by the eye.

There is speculation that PEX may be caused by oxidative damage and the presence of "free radicals", although the exact nature of how this might happen is still under study. Studies of PEX patients have found a decrease in the concentrations of ascorbic acid, increase in concentrations of malondialdehyde, and an increase in concentrations of 8-iso-prostaglandinF2a.

There is speculation that genetics may play a role in PEX. A predisposition to develop PEX later in life may be an inherited characteristic, according to one account. One report suggested the genetic component was "strong". One study performed in Iceland and Sweden has associated PEX with polymorphisms in gene LOXL1. A report suggested that a specific gene named LOXL1 which was a member of the family of enzymes which play a role in the linking of collagen and elastin inside cells. LOXL1 was responsible for "all the heritability" of PEX, according to one source. Two distinct mutations in which a single nucleotide was changed, or called a "single nucleotide polymorphism" or SNP, was discovered in Scandinavian populations and confirmed in other populations, and may be involved with the onset of PEX.

Researchers are investigating whether factors such as exposure to ultraviolet light, living in northern latitudes, or altitude influence the onset of PEX. One report suggested that climate was not a factor related to PEX. Another report suggested a possible link to sunlight as well as a possible autoimmune response, or possibly a virus.

Despite the name, the eye itself is not affected. Blunt force or trauma to the eye socket results in burst capillaries and subsequent haemorrhaging (hematoma). The fatty tissue along with the lack of muscle around the eye socket allows a potential space for blood accumulation. As this blood is reabsorbed, various pigments are released similar to a bruise lending itself to the extreme outward appearance.

The dramatic appearance (discoloration purple black and blue and swelling) does not necessarily indicate a serious injury, and most black eyes resolve within a week. The tissues around the eye are soft and thus bruise easily when pinched against margins of bone which surround the eye socket. The treatment of black eye is the same as that for bruises in other parts of the body – cold compresses during the first twenty-four hours and contrasting hot and cold thereafter. During the process of healing, a black eye can be made less conspicuous by using cosmetics designed to obscure discolorations of the skin. In a severe contusion, blowout of the floor of the orbit may occur, leading to double vision. Such an injury requires surgical correction. A black eye developing after a severe head injury may be a sign of skull fracture.

Most conjunctivochalasis is thought to be caused by both a gradual thinning and stretching of the conjunctiva that accompanies age and a loss of adhesion between the conjunctiva and underlying sclera due to the dissolution of Tenon's capsule. The resulting loose, excess conjunctiva may mechanically irritate the eye and disrupt the tear film and its outflow, leading to dry eye and excess tearing. A correlation may also exist between inflammation in the eye and conjunctivochalasis; though it is unclear if this correlation is causal. Conjunctivochalasis may be associated with previous surgery, Blepharitis, Meibomian Gland Disorder (MGD), Ehlers-Danlos Syndrome, and Aqueous Tear Deficiency,

Retinal image size is determined by many factors. The size and position of the object being viewed affects the characteristics of the light entering the system. Corrective lenses affect these characteristics and are used commonly to correct refractive error. The optics of the eye including its refractive power and axial length also play a major role in retinal image size.

Aniseikonia can occur naturally or be induced by the correction of a refractive error, usually anisometropia (having significantly different refractive errors between each eye) or antimetropia (being myopic (nearsighted) in one eye and hyperopic (farsighted) in the other.) Meridional aniseikonia occurs when these refractive differences only occur in one meridian (see astigmatism). Refractive surgery can cause aniseikonia in much the same way that it is caused by glasses and contacts.

One cause of significant anisometropia and subsequent aniseikonia has been aphakia. Aphakic patients do not have a crystalline lens. The crystalline lens is often removed because of opacities called cataracts. The absence of this lens left the patient highly hyperopic (farsighted) in that eye. For some patients the removal was only performed on one eye, resulting in the anisometropia / aniseikonia. Today, this is rarely a problem because when the lens is removed in cataract surgery, an intraocular lens, or IOL is left in its place.

Aniseikonia is an ocular condition where there is a significant difference in the perceived size of images. It can occur as an overall difference between the two eyes, or as a difference in a particular meridian.

Surgery is the most common means of repairing a cherry eye. Surgery involves gland replacement, not excision, by anchoring the membrane to the orbital rim. In severely infected cases, preoperative antibiotics may be necessary by means of antibiotic eye ointment. Removal of the gland was once an acceptable treatment, and made the eye appear completely normal. Despite cosmetic appeal, removal of the gland reduces tear production by 30 per cent. Tear production is essential in maintaining and protecting the eye from the external environment. Reduced tear production is especially problematic in breeds of animals predisposed to Keratoconjunctivitis sicca (KCS). With surgeries performed in this manner, KCS often results later in life.

KCS is common in dogs, affecting one per cent of the dog population. KCS is a chronic degenerative conjunctivitis that can lead to impaired vision and blindness. KCS has a wide array of causes including drug toxicity, cherry eye, previous surgery, trauma, and irradiation. KCS can be treated, but treatment often spans the entirety of the animal’s life.

In contrast to this, several replacement surgical procedures exist to remedy cherry eye. Replacement of the gland results in lower instances of dry eye later in life. Surgery types are broken into two groups: anchoring procedures and pocket/envelope procedures. At least 8 surgical techniques currently exist. In anchoring procedures, the prolapsed gland must be sutured to the periorbital fascia, the sclera, or the base of the third eyelid. In contrast, pocket procedures involve suturing healthy tissue around the prolapsed to enclose and secure it. Each of these techniques may be performed with an anterior or superior approach, depending on which direction of suturing will cause the least complications to the eye.