Lasers Used in Ophthalmology
The following is a short review discussing the many different lasers and how we use them in ophthalmology.
Laser Vision Correction
Laser vision correction is a very common laser eye surgery. PRK and LASIK are often advertised to reduce a patient’s need and dependance upon glasses (or contact lenses).
Both the femtosecond and excimer lasers are used to perform laser vision correction. The lasers reshape the corneal curvature which heavily influences the refraction of your eye.
Laser vision correction reduces the need for glasses in patients who have nearsightedness (myopia), farsightedness (hyperopia) and astigmatism. Certain corneal scars can also be removed with the laser.
Laser Cataract Surgery
Modern cataract surgery now involve the accuracy and dependability of the femtosecond laser. The laser can be used in crucial parts of the cataract removal process:
- creating a corneal incision (the first step)
- creating the capsulorhexis (the opening of the lens capsule)
- liquefying the cataract
- treating astigmatism, if needed
The cataract can be compared to an M & M candy. A candy coating surrounding a chocolate center. In this analogy, the cataract is enclosed by the lens capsule: the cataract is the chocolate center and the lens capsule is the outside candy coating. During cataract surgery, the “capsulorhexis” is the opening created in the front side of the cataract, the candy coating, which allow access to the cataract (chocolate) held within. Once the chocolate is removed, the IOL is placed within the candy coating, lens capsule, keeping the IOL in place.
After Cataract – Posterior Capsular Opacification
During cataract surgery, the intraocular implant is placed inside a clear tissue called the lens capsule. Just like “Saran Wrap,” this tissue is crystal clear. With time, the tissue often becomes cloudy and blurs the vision. This “after cataract” mimics the same symptoms of the original cataract, but vision can be restored with Nd:YAG laser which clears the cloudy lens capsule.
Several different lasers can be used to treat different types of glaucoma.
Open angle glaucoma, the most common form of glaucoma in the United States, is usually treated with eye drops to lower the eye pressure. When the eye drops fail to work, ALT (Argon Laser Trabeculoplasty), SLT (Selective Laser Trabeculoplasty) or MLT (Minipulse Laser Trabeculoplasty) can be used to treat patients with open angle glaucoma.
These lasers treat the drainage part of the eye, called the trabecular meshwork, to increase the absorption of internal fluid (aqueous humor) and decrease the pressure of the eye.
The laser procedures are similar and differ by the types of laser used: Argon or diode laser, Nd:YAG laser or the minipulse laser.
Laser can also be used to reduce the production of aqueous humor by treating the ciliary body. The ciliary body is located behind the iris and can be treated with argon or diode laser to reduce the production of fluid, thereby reducing eye pressure. This form of treatment is often done in conjunction with cataract surgery.
Narrow angle glaucoma is common in asians and patients with hyperopia. In this scenario, fluid is blocked from migrating through the pupil to the anterior chamber to
Retina and Vitreous
The argon laser, diode laser and minipulse laser are used to treat patients with diabetic retinopathy, swelling from various retinal vascular disorders and others. Tears in the retina are usually treated with the argon or diode laser.
Nd:YAG vitreolysis is performed for certain opacities within the vitreous.