Glaucoma: “Silent” Thief of Sight
Glaucoma is a group of conditions in which a blockage occurs in the circulation of the clear fluid (aqueous humor) that fills the front part of the eye, resulting in a higher than normal pressure within the eye. The drain is located in the anterior chamber of the eye, at the angle formed where the clear cornea meets the iris.
The high eye pressure causes damage to the tissues of the eye, especially the optic nerve and the retina (the back of the eye). Glaucoma affects the width or field of your vision and can eventually damage the sharp vision as well, even to the point of complete and total blindness.
Glaucoma usually does not give a patient symptoms until late in the disease. It is unusual to experience pain or redness, although these may occasionally occur. In addition, there is usually no blurring of vision early in the disease. For the great majority of glaucoma patients, it is a ‘silent disease,’ detected only by regular eye examinations.
Treatment for Glaucoma
Treatment options will depend on the type of glaucoma you have. Methods may include eye drops, laser surgery, medications or traditional surgery. Any vision you lose due to glaucoma cannot be regained by treatment. If glaucoma is not treated adequately, it can progress to full blindness.
The higher the pressure, the faster the visual decline. Those with glaucoma, who are suspects for glaucoma, or who have a family history of glaucoma should have regular eye examinations yearly or more often.
Due to the increased risk of glaucoma with age, even those without a family history of glaucoma should have yearly eye exams by their doctor by age forty.
Types of Glaucoma
- Open-angle glaucoma
- Angle-closure glaucoma
- Neovascular glaucoma
- Pigmentary glaucoma
- Pseudoexfoliation glaucoma
- Inflammatory glaucoma
Primary open-angle glaucoma is the most common form of glaucoma in America and Europe. This occurs when no particular reason for blockage of the drainage angle can be found. There are often no symptoms of this “silent” thief of sight. The risk factors for developing open-angle glaucoma are:
- Advanced age
- Family history of glaucoma
- Elevated intraocular pressure
- Highly pigmented skin
- Myopia (nearsightedness)
- Systemic diseases such as diabetes, hypertension and cardiovascular disease
In acute primary angle-closure glaucoma, the flow of aqueous humor (thick watery substance filling the space between the lens and the cornea) out of the eye is physically blocked by the iris. The iris, which rests abnormally close to the cornea becomes adherent to the trabecular meshwork (drain). Intraocular pressure is elevated and the patient typically experiences:
- Excruciating pain
- Blurred vision
- Halos around lights
Neovascular glaucoma is a special situation caused by blockages in retinal veins or arteries or proliferative diabetic retinopathy. This glaucoma develops due to abnormal blood vessels growing on the iris and in the drainage angle between the iris and the clear cornea. They eye pressure can become quite high and symptoms include:
- Chronically red, painful eye
- Sensitivity to light
Pigmentary glaucoma is caused by pigment dispersion, a disorder characterized by pigment liberation from the iris epithelium. Onset is at a somewhat early age, developing in 20 to 40-year-old patients and is more likely in near-sighted patients. A distinguishing feature of pigmentary glaucoma is that the iris tends to have a concave (bowed back toward the lens) configuration.
Pseudoexfoliation glaucoma is a systemic disease characterized by whitish-gray protein deposits on the lens, iris, ciliary and corneal endothelium and trabecular meshwork drain. Accumulations of this protein material decrease aqueous humor outflow and increase intraocular pressure.
Inflammatory glaucomas are glaucomas caused by or associated with inflammation (not usually infection) of the eye. The eye pressure is elevated as the white cells block the drain between the iris and cornea.
Intraocualr pressure can be very high and can be recurrent during bouts of inflammation.
Typically, there is a tendency for scarring of the iris to the cornea and lens. Sympotms include decreased vision, floaters, redness and eye pain – especially an ache in the eye or eye brow.