Some cataracts may arise following injuries to the eye, severe inflammatory diseases of the eye, or the use of certain oral medications (particularly cortisone-like steroids). The development of cataracts may be accelerated by some general systemic illnesses, such as diabetes. Smoking and excessive sunlight exposure may also hasten cataract growth.

Cataract surgery may be performed at any age. Surgical techniques have improved tremendously in recent years, and the vast majority of patients have excellent results. An artificial lens implant is nearly always placed in the eye at the time of surgery. With the newer techniques involving small incisions, the recovery time is more rapid, and the there is usually less discomfort and blurred vision right after the surgery.

Most patients with glaucoma do have elevated intraocular pressure. Along with the eye pressure, other parameters are evaluated in the search for glaucoma, such as peripheral vision, visual contrast sensitivity, optic nerve cupping (a hollowing out of the center of the optic nerve head in the back of the eye), and gonioscopy (visualizing the anatomy of the filtering angle of the eye, where the cornea and the iris join).

Glaucoma may occur in infancy or childhood, but is most common in adults. It is categorized into many different types, according to whether it is sudden (acute) or gradual (chronic) in its onset, whether the filtering angle is open or narrow or closed, whether it is a primary or a secondary disease (secondary to another eye disease, systemic illness, injury, or medication), and the age of onset.

The most common type of glaucoma is primary open angle glaucoma. This is usually completely painless and most patients are not aware that they have it unless they undergo a thorough eye examination. Loss of vision is usually very gradual and occurs over many years. Narrow angle glaucoma may be seen in an acute form, with sudden onset of severe pain, blurred vision, and very high intraocular pressure, or in a chronic form, with gradual loss of peripheral vision due to optic nerve damage. Inflammatory eye diseases, severe eye injuries, some hereditary conditions, and cortisone- related steroid medications may also cause glaucoma.

In most patients, glaucomatous damage to optic nerve fibers results in a gradual loss of peripheral vision. This is detected with a visual field test, usually performed on an automated computerized visual filed analyzer that can accurately map out the peripheral vision and compare it to age-based norms and to previous visual field tests performed on the same patient. This trend of visual field loss progression over time is very important in the monitoring and management of glaucoma.

Glaucoma can be successfully treated in most patients. Initially, most patients are treated with pressure-lowering eyedrops. There are various types of drugs that are used as drops to treat glaucoma, and some patients require more that one type of drop. Some of these drops cannot be used in patients with asthma, emphysema, other lung diseases, congestive heart failure, very slow heart rate or skipped heart beats. In fact, just one drop can be fatal in some patients with these conditions. Therefore, it is vitally important that the patient and doctor be aware of any of these medical conditions before a patient starts these particular eyedrops, known as beta blockers. If eyedrops alone do not adequately control the glaucoma, then other treatment options are available. Oral medication, acetazolamide and methazolamide, help reduce fluid production within the eye and provide additional pressure-lowering effects. These medications usually should be avoided in patients with an allergy to sulfa-type medications, because there can be allergic cross-reactions.

Various laser treatments are used in glaucoma management. Laser trabeculoplasty involves treating the filtering angle area of the eye with many tiny 50 micron (.05 mm) laser burns to improve fluid drainage out of the eye and lower the pressure. This laser procedure is used in patients with open angle types of glaucoma. Narrow angle glaucoma is often treated with laser iridotomy. A laser creates a small opening in the peripheral iris. This helps to prevent fluid from building up behind the iris and forcing it forward, which would close off the filtering angle. Several other types of laser treatment are also now available for treating glaucoma.

Some patients with severe glaucoma, that cannot be well controlled with medications or laser, may require surgery. Most glaucoma surgeries reduce eye pressure by providing an alternate route for fluid to gradually drain from within the eye. A small opening is created in the wall of the eye (the sclera) and the fluid drains slowly into a small bleb, which is a pouch-like elevated area of conjunctiva (the thin transparent layer over the sclera). Variations of this procedure include injection of chemotherapy agents to reduce scarring which could cause bleb failure, insertion of silicone shunts to help keep the drainage channel open more permanently, the use of temporary adjustable sutures that allow better control of eye pressure after the surgery, and the use of holmium laser rather than surgical instruments to create the drainage opening.

Most of these glaucoma surgeries are successful, but certain factors and conditions can make surgical success less likely, such as previous eye surgeries, eye inflammation, growth of abnormal blood vessels into the eye (neovascular glaucoma), racial influences (black patients tend to have worse glaucoma at the time of diagnosis and may develop more inflammation after surgery), and age (younger patients often have greater inflammation following surgery and therefore have a higher failure rate).

A much more serious eye disorder is diabetic retinopathy. This is the leading cause of new cases of legal blindness in the United States for patients aged 20 to 64 years. After 7 years of diabetes, approximately 50% of patients will have diabetic retinopathy and after 17 to 25 years of diabetes, 90% will have at least some form of diabetic retinopathy.

The early stage of retinopathy is classified as background diabetic retinopathy. At this stage, most patients aren't even aware they have it, because many of them have no symptoms or only experience mild blurring of the central vision. This early stage of retinopathy is characterized by enlarged retinal veins, tiny retinal hemorrhages, small dot-like dilations of blood vessel capillaries called microaneurysms, small yellowish deposits in the retina called hard exudates, and areas of retinal swelling, particularly in the macula (center of the retina).

This central retinal swelling is called macular edema, and it may cause significant blurring of vision. Fluorescein angiography is a retinal photographic procedure that involves injection of a fluorescent dye into the bloodstream to detect areas of leakage in the retina. This is also helpful in guiding laser treatment. A laser procedure, called focal macular photocoagulation, is used to treat the areas of retinal swelling caused by leakage from microaneurysms. Vision loss also can be caused by blockage of tiny blood vessels in the macula, resulting in a problem called ischemic maculopathy. There is no effective treatment for this problem.

As retinopathy worsens, the changes of background retinopathy become more prominent, the blood flow to the retina worsens, areas of retina become deficient in oxygen, and abnormal new blood vessels may begin to grow within the retina or on its surface (neovascularization). This process is caused by an angiogenic factor released from the areas of retina that are deficient in oxygen. It is the body's flawed attempt to provide more blood supply (and thus oxygen) to the retina. Unfortunately, these blood vessels are abnormal and cause serious problems inside the eye. This more advanced stage of diabetic retinopathy is called proliferative retinopathy, because of the proliferation of abnormal blood vessels within the eye. If these abnormal vessels are detected by the ophthalmologist, laser treatment is usually recommended.

These fine delicate abnormal vessels are fragile and can break and cause bleeding within the eye. If the blood flows into the vitreous gel in the back chamber of the eye, this is called a vitreous hemorrhage. This can suddenly and profoundly affect the vision. If the blood resorbs on its own, then laser treatment can be performed. If the blood does not clear, then a surgical procedure, known as vitrectomy, is performed to remove the blood and cloudy vitreous gel.

Panretinal photocoagulation (PRP) is the laser treatment used to treat proliferative diabetic retinopathy. It involves the placement of approximately 500 to 1500 laser treatment burns per session to the retina. Although one session may be enough to cause regression of the abnormal proliferative vessels, many patients require two or more sessions to achieve regression. The laser burns actually destroy a portion of the ischemic retina (ischemic means deficient in oxygen supply). This treatment interrupts the cycle of ischemia causing release of angiogenic factors which in turn would cause growth of the abnormal proliferative blood vessels.

Proliferative retinopathy can also result in the growth of bands of scar tissue within the vitreous gel and on the retina. These bands or membranes of scar tissue have the ability to contract and this can result in pulling on the retina and causing a retinal detachment. If this occurs, retinal surgery may become necessary, including vitrectomy (removal of vitreous gel), membranectomy (excision of the membranous scar tissue), endolaser (laser treatment through a small tube inserted into the eye), and in more severe cases, the injection of air or other gases into the vitreous chamber to compress the retina flat and maintain it in place until it adheres.

Other eye problems that diabetic patients may encounter include double vision from damage to the cranial nerves that control eye muscles, and an increased risk of developing open angle glaucoma and cataracts. Also atherosclerosis is more prevalent among diabetics. This build-up of cholesterol plaque causes narrowing in arteries and can lead to heart disease, stroke, blocked arteries in the extremities, and loss of vision from damage to the retina or optic nerve from occluded smaller blood vessels, called arterioles.

Retinal neovascularization, the growth of abnormal new vessels on the surface of the retina, can occur in other disorders as well, including sickle cell anemia, occlusion of the central retinal vein or artery, severe eye inflammation, eye tumors, and following retinal detachments.

Additional factors that may hasten loss of the RPE layer and the resulting degeneration of the central retina (macula) include hereditary factors, ultraviolet rays from sunlight, and blue iris color (more UV rays reach the retina in blue-eyed patients, probably because of the lower pigment density in the eye).

There are basically two forms of macular degeneration. So-called dry (or atrophic) macular degeneration is characterized by tiny yellowish deposits under the macular part of the retina. These deposits are known as drusen and may increase in number and size over time. Also areas of loss of retinal and RPE layers in the macula may gradually appear. Small clumps of brown pigment from the degenerating RPE layer also are commonly seen.

The other major form of this disease is wet (or exudative) macular degeneration. This type can be associated with more sudden loss of vision due to leakage or bleeding under the macula from abnormal vessels arising from one of the deeper layers, called the choriocapillaris. Eventually these areas of bleeding or fluid accumulation can develop into a dense mass of scar tissue beneath the retina, resulting in permanent loss of central vision.

If the neovascular membrane is detected early, in some cases it can be treated with laser to try to dry it up and prevent further leakage or bleeding. Although laser treatment is very effective in many patients with this problem, vision that has already been lost often cannot be regained. The goal in many cases is to try to prevent or reduce further loss of central vision in the future. Periodic eye examinations are important following laser treatment, because the neovascular membranes are notorious for re-appearing again later.

Research has indicated that some preventive health measures may slow the onset and progression of macular degeneration. Vitamins A, E and C, as well as zinc and selenium have been advocated as potentially useful in slowing macular degeneration. Recently there has been some controversy regarding the true value of zinc in the prophylaxis of macular degeneration.

Hypertensive retinopathy is caused by blood vessel changes in the retina due to extremely high blood pressure, but it not seen as frequently now because of the availability of excellent antihypertensive medications. In the past, when very high blood pressure was more commonly encountered, classic hypertensive changes in the eye were often observed. These changes include narrowing of the retinal arterioles, dilation of retinal veins, small retinal hemorrhages and white patches of retinal swelling, and in severe cases, optic nerve swelling. Hypertensive retinal changes usually completely resolve after the blood pressure is adequately controlled.

Other diseases, such as leukemia, various types of cancer, drug toxicity, parasitic infections, and fungal infections also may cause injury to the retina or deeper choroid layers of the eye.