Glaucoma is a chronic disease of the eye that gradually reduces sight without symptoms. Experts estimate that approximately half of the people affected by glaucoma may not know they have it. It is known as the “sneak thief of vision” because the symptoms of the disease are hardly noticeable. Fortunately, it can be readily diagnosed by a thorough eye exam. Vision loss from glaucoma is caused by damage to the optic nerve. While there is no cure for glaucoma, early detection and treatment can preserve your sight. Treatment involves lowering the eye pressure using medications, laser glaucoma surgery or filtration surgery.
Open angle glaucoma is the most common type of glaucoma, occur when ocular fluid cannot pass through the eye’s filtration system (trabecular meshwork) to the drainage channels. It is the most common type of glaucoma damaging vision gradually and painlessly. The pressure is rarely high enough to be symptomatic. An examination of the optic nerve by an ophthalmologist is essential for early detection.
Closed or Narrow-angle glaucoma is much less common and accounts for less than 10% of all glaucoma’s. Eye pain, redness and blurred vision can be symptoms of narrow angle glaucoma. People with Hyperopia or farsightedness and people with Asian ancestry are more at risk for closed angle glaucoma.
Laser iridotomy is a non-invasive surgical therapy used to prevent or treat narrow angle glaucoma. In patients with narrow angles or narrow angle glaucoma, the space between the iris and the cornea is not as wide and open as it should be. When the angle is narrow, the iris “bunches up” over the drainage canals and blocks the outflow of fluid inside of the eye, causing a glaucoma attack. Glaucoma attacks are painful and can cause permanent loss of vision.
The laser is a tiny but powerful beam of light that can make a small burn or opening in tissue. The laser is used to remove a small portion of the bunched up iris which immediately unblocks part of the drainage canals and allows fluid to drain into the drainage system.
On the day of the laser therapy, you will receive eye drops to make the pupil smaller, and to control inflammation in the eye scheduled to have the laser. These eye drops sometimes cause a temporary brow ache or headache.
During laser surgery, you will see a bright light, like a camera flash, and you will feel a pinch or tingling sensation. Afterwards, the eye may be slightly irritated, and you are advised to avoid strenuous activity for a few days.
With laser iridotomy, the more common risks include:
Selective Laser Trabeculoplasty
Selective Laser Trabeculoplasty or SLT is a non-invasive surgical therapy for glaucoma that is proven to be effective and is approved by the FDA. It is safe and long term studies, greater than 10 years, show that patients who had SLT showed no negative impact. The laser is a tiny, low-energy beam of light that passes harmlessly through the outer covering of the eye and targets the pigment cells of drainage system of the eye. The body’s natural healing system responds to the light energy by healing the drainage cells, restoring its natural pressure relieving functions. SLT lowers eye pressure. SLT is safe as a primary, adjunctive, or repeat therapy to reduce intraocular pressure.
What is a Trabeculectomy?
A trabeculectomy is drainage surgery used in the management of glaucoma.The term Trabeculectomy refers to making a hole in the drainage area of the eye, to allow fluid from inside the eye to be released, thereby lowering the intraocular pressure.
Why do I need a Trabeculectomy?
Most glaucoma is treated by medical therapy in the form of eye drops. In most cases the eye pressure is sufficiently lowered by the eye drops to reduce the risk of vision loss from glaucoma. In some cases the pressure lowering is not sufficient and requires further treatment. The current options are tablets, laser or drainage surgery. Generally, tablets are only used in the short-term for pressure control as they are associated with side-effects. Laser, also, does not generally have a long-term effect and is utilized mainly if surgery is not safely possible.
What is involved with Trabeculectomy?
Trabeculectomy is performed as Day Surgery and does not require overnight admission. It is necessary to stop aspirin, Warfarin, anti-inflammatory, fish oil or any other blood thinning medications 7 days prior to surgery. Local anesthesia with sedation is preferred as it is safer for the patient and provides more rapid recovery. A general anesthesia can be performed in certain patient indications. The procedure takes one to one and a half hours, depending on the complexity of the glaucoma.
The aim of the surgery is to create a one-way flap valve from the inside of the eye to under the conjunctiva of the eye. The fluid subsequently passes from this small reservoir (bleb) back into the blood vessels of the conjunctiva. It does not result in more tearing from the eye as there is no external drainage of the fluid. During the operation anti-scarring agents such as Mitomycin C are used to optimize the long-term drainage of the fluid from the eye.
Glaucoma detection needs regular follow-up since the condition can cause asymptomatic and irreversible loss of vision if poorly treated or neglected. Have a routine eye check every 18 – 24 months if you are age 40 years or over. Every 12 months if a family member has glaucoma, if you have had a serious eye injury in the past, or if you are taking steroid medication [tablets or eye drops].
For glaucoma patients the effect of treatment on the eye pressure may not always be constant and needs to be regularly measured by the glaucoma specialist.Maintaining records of your eye condition for comparison on following visits is very important.The prescription must never be altered or stopped without consulting your doctor.
Suspect cases with a family history of glaucoma may be required to additionally undergo a highly sensitive form of visual field analysis called short wavelength automated perimetry [SWAP], which detects changes in your eye well before the optic nerve shows the effects of glaucoma.