PRK - Corneal Transplant - Glaucoma Laser Surgery

PRK (photorefractive keratectomy)

PRK or photorefractive keratectomy is one of the safest and most time-tested laser vision correction procedures available. Like LASIK, it reshapes the cornea to improve vision.

In PRK the surgeon uses an excimer laser to vaporize a small amount from the top of the cornea. LASIK, by contrast, cuts a deep flap in the cornea using a sharp microkeratome blade. This weakens the cornea, makes it difficult to replace the flap in precisely the right place, and can cause other complications including flap irregularity, epithelial ingrowth and corneal ectasia. PRK avoids these risks.

Corneal Transplant (keratoplasty)

The cornea is the clear covering on the front of the eye which bends, or refracts, light rays that focus on the retina in the back of the eye. A certain shape or curvature is required in order for light to focus exactly on the retina, rather than in front of it or behind it.

An improperly curved cornea may be corrected surgically or non-invasively to reduce or eliminate the need for eyeglasses or contact lenses. A thorough eye examination and consultation are necessary before a treatment decision can be made.

Transplantation involves replacing the damaged cornea with a healthy one from a donor (usually through an eye bank). Keratoplasty is a low-risk procedure - it is the most common type of transplant surgery and has the highest success rate.

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Glaucoma Laser Surgery

Glaucoma is an eye disease in which pressure inside the eye (intraocular pressure) rises dangerously high, damaging the optic nerve and causing vision loss. In a healthy eye, fluid is produced in the ciliary body, enters the eye, and then drains through tiny passages called the trabecular meshwork. In people with glaucoma, these passages become blocked and intraocular pressure rises.

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Some cases of glaucoma can be treated with medications. For others, laser or traditional surgery is required to lower eye pressure. Common surgeries include:

• Laser Peripheral Iridotomy (LPI) – For patients with narrow-angle glaucoma. A small hole is made in the iris to increase the angle between the iris and cornea and encourage fluid drainage.
  
• Argon Laser Trabeculoplasty (ALT) and Selective Laser Trabeculoplasty (SLT) – For patients with primary open angle glaucoma (POAG). The trabecular passages are opened to increase fluid drainage. ALT is effective in about 75% of patients, and SLT may be repeated.
• Nd:YAG Laser Cyclophotocoagulation (YAG CP) – For patients with severe glaucoma damage who have not been helped with other surgeries. The ciliary body that produces intraocular fluid is destroyed.

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About 1 in 10 glaucoma patients has primary angle closure glaucoma. This type of glaucoma occurs when the trabecular meshwork becomes blocked. Most patients have no symptoms. Treatment involves making an incision in the iris to restore the proper flow of aqueous fluid (an iridectomy or iridotomy) or creating a new, clear channel in the sclera (the white part of the eye) for the fluid to travel through (a trabeculectomy). Patients are often given medications in addition to these procedures to ensure that the glaucoma is kept under control.

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A few patients experience acute angle closure glaucoma, a sudden rise in intraocular pressure that frequently causes blurred vision, severe pain, colored halos, reddened eyes, and nausea or vomiting. Immediate treatment is critical. Eye drops or oral medications are usually prescribed to lower pressure and swelling and allow the physician to examine the eye. When the eye has been stabilized, an iridectomy or iridotomy may be performed.

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PRK - Corneal Transplant - Glaucoma Laser Surgery