What is Glaucoma?
Millions of Americans have Glaucoma, but almost half of them don’t realize they have it. It is a typically a painless and slow progression, so it can steal vision without warning–the “silent thief of sight”.
In Glaucoma, the optic nerve gets damaged due to elevated eye pressure. The eye pressure elevates due to fluid build-up inside the eye. This is totally unrelated to fluid outside the eye, like tears. Since the nerve transmits images from the eye to the brain, a damaged optic nerve leads to vision loss and blindness. Tragically, this nerve damage is permanent and irreversible.
The vision loss starts with subtle changes in the peripheral vision, which become more obvious as the disease progresses. Late in glaucoma, the vision loss encroaches upon the central vision.
Risk factors include eye pressure, age (over 45y), race (Hispanics, Asians, African Americans), genetics (family history of glaucoma) and other eye problems (like a history of eye injury, severe near-sightedness, pseudoexfoliation). Risk factors are not guarantees–for example, a 30 year old can get Glaucoma, but it is more likely (higher risk) in older patients.
The eye pressure most of our attention since it can be lowered with laser, eye drops and other surgical procedures.
Glaucoma can be tricky to diagnose since not everyone with high eye pressure goes on to develop optic nerve damage (ocular hypertension). There are other situations where optic nerve damage can develop without elevated pressures (low pressure glaucoma).
Open Angle Glaucoma and Treatment
The angle of the eye is basically the drainage channel. In the various types of open angle glaucomas, the angle is ‘open’, but not working at full capacity, causing fluid and pressure to build up inside the eye. Open angles are far more common than narrow or closed angles in the US. Fortunately, there are many excellent treatment options for glaucoma to help lower the eye pressure.
- SLT–Selective Laser Trabeculoplasty
SLT is a simple, painless and highly effective laser procedure done in the office. The laser treatment helps the angle work better, allowing the fluid to flow out more easily and thereby lowering the eye pressure. This is Dr. Parekh’s preferred treatment for newly diagnosed open angle glaucoma because of its convenience and effectiveness.
- Eye Drops
Another common way to treat glaucoma is with various eye drop medications that help decrease the amount of fluid made in the eye, or help increase the amount of fluid leaving the eye. Eye drops can have significant side effects and also significant costs associated with them. In addition, the patient must remember to put the eye drops in every day, sometimes multiple times per day.
- Surgical Options
If simple options like SLT or eye drops are not doing enough to control the eye pressure, there are other surgical options available;
The first line of surgical options are the minimally invasive techniques like the iStent. These types of surgeries often help prevent the need for major glaucoma surgeries like Tube Shunts or Trabeculectomy, which have a higher complication rate.
The iStent is performed along with cataract surgery and the device helps bypass the Trabecular Meshwork–an area that prevents the outflow of fluid.
ECP is a laser procedure often performed along with cataract surgery. The laser helps decrease the production of fluid in the eye, thereby lowering the eye pressure.
KDB–Kahook Dual Blade
The KDB is a newer technique that helps bypass the Trabecular Meshwork, helping to lower the eye pressure.
Trab 360 Trabeculotome
This procedure opens the Trabecular Meshwork for 180 or 360 degrees, again bypassing the site of resistance and helping to lower the eye pressure.
Visco 360 Canaloplasty
This procedure dilates Schlemm’s canal, which is located behind the Trabecular Meshwork. This allows for increased fluid outflow and helps to lower the eye pressure.
Narrow Angle Glaucoma and Treatment
In the narrow and closed angle glaucomas, the angle is obstructed or at high risk for obstruction. This would prevent fluid from draining, leading to pressure build up. This can happen suddenly (‘attack of angle closure glaucoma’–sudden eye pain, redness, headache, nausea/vomiting) or gradually (chronic angle closure).
LPI–Laser Peripherial Iridotomy
The initial treatment to open the angle is LPI, a simple and effective in-office laser procedure. A tiny opening is created in the iris, allowing the pressures in the eye to equalize, thereby opening the angle.
Lens Replacement Surgery
On occasion, the angle does not open after LPI. In that situation, lens replacement surgery (very similar to cataract surgery) is performed.
The lens is a relatively large structure within the eye, and can cause the crowding that leads to narrow or closed angles. Lens replacement surgery involves removing that large lens and replacing it with a much smaller, man-made lens, thereby opening the angle.
There are also times where an LPI succeeds in opening the angle, but then the angle becomes narrow again over time. In that case, lens replacement surgery is the treatment of choice.