Glaucoma is a group of eye diseases that cause progressive damage to the optic nerve, which transmits visual information from the eye to the brain. This damage is often associated with elevated pressure inside the eye, known as intraocular pressure (IOP). LASIK, or Laser-Assisted In Situ Keratomileusis, is a popular type of refractive surgery that corrects vision problems. LASIK does not treat, fix, or cure glaucoma, as it addresses the eye’s focusing power, not the health of the optic nerve.
Understanding Glaucoma
Glaucoma is fundamentally an optic neuropathy, characterized by the degeneration of retinal ganglion cells. This leads to changes in the optic disc and a gradual, irreversible loss of peripheral vision. The primary manageable risk factor is persistently high intraocular pressure (IOP).
The eye constantly produces aqueous humor, a clear fluid that fills the front part of the eye. This fluid must drain at a balanced rate to maintain stable pressure. Glaucoma occurs when the drainage system, primarily the trabecular meshwork, fails, causing fluid to build up.
The most common form is Primary Open-Angle Glaucoma, where the drainage angle appears open but the meshwork is partially clogged, leading to a slow pressure rise. Angle-Closure Glaucoma is less common, where the iris blocks the drainage angle completely, causing a sudden spike in IOP. Glaucoma is a chronic condition requiring long-term management to lower pressure and prevent further nerve damage.
Understanding LASIK Surgery
LASIK is a laser-based surgical procedure designed to correct common refractive errors, such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. These errors occur when the eye’s shape prevents light from focusing correctly on the retina. The purpose of LASIK is to reshape the cornea, the clear outer layer of the eye, to improve focusing power.
The procedure involves creating a thin flap on the cornea’s surface using a microkeratome or a femtosecond laser. This flap is lifted, and an excimer laser vaporizes underlying corneal tissue, sculpting the cornea into a new curvature. After reshaping, the flap is repositioned, adhering without stitches. The procedure is purely an optical correction and does not affect the eye’s internal drainage system or the optic nerve, which are the structures relevant to glaucoma.
The Effect of Prior LASIK on Glaucoma Diagnosis
While LASIK does not treat glaucoma, having the procedure complicates future monitoring. Standard methods for measuring intraocular pressure (IOP), such as Goldmann applanation tonometry, rely on pushing against the cornea. This measurement is accurate only if the central corneal thickness (CCT) is within the normal range.
LASIK thins the cornea by removing tissue, altering the physical properties of the eye’s surface. A thinner cornea offers less resistance to the tonometer, causing the reading to be artificially low. This reduced IOP reading can mask true eye pressure, potentially leading to a delayed diagnosis or inadequate treatment.
Professionals must account for this change using correction factors or advanced diagnostic tools. Optical Coherence Tomography (OCT) assesses the thickness of the nerve fiber layer and the optic nerve head, looking for structural damage regardless of the IOP reading. The suction ring used during LASIK temporarily raises IOP, which is a consideration for at-risk patients. Steroid eye drops prescribed after LASIK can also temporarily increase eye pressure, complicating post-operative monitoring.
Actual Treatments for Glaucoma
Since LASIK is ineffective against glaucoma, treatment focuses on lowering intraocular pressure to prevent further optic nerve damage. The initial approach involves medicated eye drops, which work by decreasing the production of aqueous humor or by increasing its outflow through the drainage system. Prostaglandin analogs are a common first-line medication that enhances fluid drainage.
When drops are insufficient or poorly tolerated, laser procedures offer a minimally invasive alternative. Selective Laser Trabeculoplasty (SLT) is a common treatment for open-angle glaucoma that uses a laser to stimulate the trabecular meshwork, improving fluid drainage. For angle-closure glaucoma, a Laser Peripheral Iridotomy (LPI) creates a small opening in the iris to relieve the pressure blockage.
If medications and laser treatments fail to control the pressure, traditional surgery becomes necessary to create a new drainage pathway. Options include trabeculectomy or the implantation of drainage devices. Minimally Invasive Glaucoma Surgeries (MIGS) are also an option, offering quicker recovery times for managing mild to moderate cases, often performed with cataract surgery.