Glaucoma is a leading cause of blindness, but what is it? Glaucoma, once thought to be a disease defined by abnormal intraocular pressure, it is now more properly thought of as a disease that affects the optic nerve and vision in a specific way. Early detection is important in mitigating visual loss from this insidious disease.
But what is glaucoma? It was once felt that any pressure over 21 represented glaucoma. However studies have shown that a significant number of glaucoma patients were never found to have high pressures. To further confuse the picture many people with high pressures will never develop the disease. Most types of glaucoma are considered to be primary open-angle glaucoma. What this means is that people with this disease have a characteristic visual field loss and optic nerve appearance. Many experts now think that this may be a result of an imbalance between the intraocular pressure (pressure within the eye) and cerebral spinal fluid pressure.
Secondary glaucoma is often associated with elevated intraocular pressure which resulted from damage to the angle between the iris and cornea where fluid (aqueous humor) exits the eye. Conditions that can cause this are ocular trauma, diabetes, inflammation, as well as many other causes.
While everyone needs to be screened for glaucoma we have learned from studies that certain groups of people need closer follow-up as they are in a high risk category. These people have questionable objective signs such as high intraocular pressures, thin corneas, characteristic optic nerve changes, visual fields that deviate from the norm, and perhaps most importantly, thinning of the nerve fiber layer of the retina surrounding the optic nerve detected by optical coherent tomography.
Additional risk factors include the elderly, family history of glaucoma, certain ethnic groups such as people of African and Hispanic descent. Asians also have a propensity to develop glaucoma and represent 87% of the cases worldwide. While we know it is important to follow high risk patients closely it can be sometimes confusing when to treat. For instance as mentioned before, while most people with abnormal pressure elevations won’t develop glaucoma the ocular hypertension study (OHTS) noted that people with pressures between 24 and 32 had a 9.5% chance of developing glaucoma five years down the road. Some Ophthalmologists will treat at this point while many may prefer to observe these patients closely. When the disease is firmly diagnosed as per visual field loss along with nerve fiber loss and optic nerve changes, aggressive treatment is necessary in young people as they have many years left to live with this disease. On the other hand people well advanced in years who may have other medical problems may not require such aggressive treatment.
In office selective laser treatment (SLT) which is covered by insurance, is an excellent option for these people, as well as most others, since it is cost effective and free of side effects. Other forms of treatment consist of eye drops which are effective but can be expensive. In addition many people are forced to use generic drops for cost reasons that may have greater side effects and less potency. Finally surgery is also an option but luckily this doesn’t have to be performed often as long as patients are diagnosed and treated in timely fashion.
At North Shore Eye Care we have the latest diagnostic equipment to screen you for this disease at any of our many locations mentioned in our website by our well established board certified Ophthalmologists.