iStent® for glaucoma
What is glaucoma?Glaucoma is a family of diseases that affect pressure within the eye, eventually damaging the optic nerve to cause vision loss or blindness. When pressure inside the eye increases, blind spots in peripheral vision may develop. Glaucoma is one of the leading causes of blindness in the United States. Often called the "silent thief" of sight, most forms of glaucoma do not produce symptoms until vision is already severely impaired. If diagnosed early, the disease can be controlled and permanent vision loss can be prevented.
What are the risk factors for glaucoma?Although glaucoma is most common in adults over the age of 40, susceptibility is not determined by age alone. There is a hereditary/genetic component, such that those with a family history of the disease, and particularly those who are African-American, are at increased risk. Additionally, patients with hypertension, diabetes, and other systemic cardiovascular diseases are at higher risk. Because there are no symptoms of most glaucoma variants, individuals in the general population should have a glaucoma evaluation every two or three years after the age of 40, followed by every one or two years after the age of 60. However, those with significant risk factors as indicated above would need to be monitored more closely.
Common Types of Glaucoma:• Open angle glaucoma: this is the most common type of glaucoma in the United States. This occurs when the eye creates aqueous fluid, but the fluid cannot drain properly through the eye's drainage anatomy, called trabecular meshwork.
• Narrow angle or closed angle glaucoma: this occurs when the approach to the drainage anatomy (trabecular meshwork) is narrowed or obstructed by the iris (colored part of your eye). When the aqueous fluid cannot reach the drain, the eye pressure will increase. If the eye pressure stays too high for too long, optic nerve damage will result, causing a loss of peripheral vision, which can culminate in total blindness. This type of glaucoma tends to occur in people who are farsighted or have a family history of narrow angles. Unlike the silent, open angle glaucoma, narrow angle glaucoma sometimes has prodrome symptoms of headaches or eye pain with blurry vision, due to intermittent angle closure events. On the other hand, an acute and sustained angle closure attack will cause severe pain, redness, light sensitivity, and blurry vision from a high spike in eye pressure, which can rapidly damage the optic nerve.
Treatments for Glaucoma:Open angle glaucoma: glaucoma treatment at the ocular level is aimed at decreasing intraocular pressure to prevent damage to the optic nerve. Therapies may include:
- Eye drops (or a combination of eye drops and pills) to reduce intraocular pressure. Several different classes of glaucoma medications are available to achieve pressure reduction. These medications, all of which may have ocular or systemic side effects, work by either reducing the rate at which fluid in the eye is produced or increasing the outflow of fluid from the eye. It is important that we, as your medical eye doctors, are aware of your complete medical history, such that we cater the medical therapy to minimize your potential systemic side effects.
- iStent®: For patients with mild to moderate glaucoma, the iStent® device is an exciting FDA approved implant option for lowering intraocular pressure. The iStent® is the world's smallest medical implant device. It is implanted into the trabecular meshwork at the same time as the cataract surgery, without need for additional anesthesia, and no additional corneal incisions. Clinical trials demonstrated that patients who had cataract surgery combined with iStent® placement had lower eye pressures and required fewer glaucoma drops, when compared with patients who had cataract surgery alone. The iStent® may help reduce a patient's medication burden, reducing the cost, inconvenience, or side effects of using glaucoma drops. The iStent® may also help delay or avoid the need for more risky surgical interventions in the future. The iStent® is covered by most insurances, and it is considered a minimally invasive form of glaucoma surgery. If you are on drops for glaucoma and are to undergo cataract surgery, this may enable you to achieve better glaucoma control and/or reduce your dependency on topical glaucoma medication.
- Laser treatment(s) to open the drainage angle and reduce intraocular pressure is an option to reduce medication burden or augment the benefits of medications:
- Intraoperative surgical options: Surgery is usually reserved for cases that cannot be controlled by medication or office laser treatments. In general, the options include creating an accessory outlet for fluid (trabeculectomy), inserting a tube device for fluid drainage, or ablating the ciliary body (which creates the fluid).
Narrow angle or closed angle glaucoma: The first line treatment for narrow or closed angle glaucoma is a laser peripheral iridotomy (LPI). This involves using a laser beam to make a microscopic hole in the iris. The opening improves the shape of the front part of the eye and allows the aqueous to better access the drainage system of the eye (trabecular meshwork).
Is blindness from glaucoma preventable?Regular diagnostic examinations by an ophthalmologist are the key to preventing vision loss from glaucoma. Ophthalmologists are medical doctors, specialists in eye care and trained to examine and treat eye diseases. Although there is no way to reverse damage, if glaucoma is diagnosed and treated early, blindness is almost always preventable!