Limbal Relaxing Incisions
Limbal relaxing incisions (LRI) got their start almost a century ago, when ophthalmologists
noticed that incisions in the curve of the cornea affected the refractive power.
Initially performed on injured eyes, these findings prompted Dutch and Japanese
eye surgeons to purposely place incisions in healthy eyes to improve vision.
During the mid-1970s in Russia, a surgeon named Fyodorov began treating myopia in patients using radial or spoke cuts through 90-95% of the cornea. Technically referred to as radial keratotomy (RK), this procedure weakened the peripheral cornea and caused it to balloon in shape, thereby flattening the central cornea. Results, although not as accurate as laser correction, were fair but occasionally unstable, both visually and anatomically. Limbal relaxing incisions are a variation on the theme of RK, but less drastic, much safer and more reliable.
Limbal relaxing incisions are often combined with cataract surgery to reduce pre-existing astigmatism. The result is better vision without glasses. This procedure can also be used outside of cataract surgery, in individuals whose primary refractive error is astigmatism.
How it works
The outer layer of the eye can be divided into three basic areas: the cornea, the sclera and the limbus. The cornea is the clear part, or the window that covers the iris and the pupil. The sclera is the white part of the eye. The limbus is the thin area that connects the cornea and the sclera.
Limbal relaxing incisions treat low to moderate degrees of astigmatism. Astigmatism is present when the cornea is not rounded, but instead, is steeper in one meridian than the opposite meridian, 90 degrees away. Thus, a cornea with astigmatism may be thought of as being more football shaped rather than the normal basketball shape.
Limbal relaxing incisions are placed on the far peripheral aspect of the cornea (the limbus) resulting in a cornea that is more round. The astigmatism is thus reduced and uncorrected vision is improved.
Limbal relaxing incisions are routinely applied to 0.5-3 diopters of astigmatism. Limbal relaxing incisions can be performed either at the time of cataract surgery or as an independent procedure.
The following procedural outline is based on the limbal relaxing incisions being done as a procedure separate from cataract surgery. If done with cataract surgery, as is more the norm, then of course the procedure would vary accordingly.
- You will arrive at the laser center 1 hour prior to your procedure. Once you have been checked in you may be offered a sedative to help you relax.
- You will be prepared for surgery. The area around your eyes will be cleaned and a sterile drape may be applied around your eye. Anesthetic eye drops will be used to numb your eyes; no injections or needles will be used. When your eye is completely numb, an eyelid holder will be gently placed between your eyelids to keep you from blinking during the procedure. A saline solution keeps your eyes moist.
- Marks will be made on the limbus. These impressions are temporary and used for indicating the location where Dr. Seibel will make the incisions. The marks are based upon a formula taking into account your prescription, age and the amount of correction needed.
- Tiny arc shaped incisions will be made in your limbus. Finally, antibiotic drops will be applied and the eyelid holder will be removed. The actual surgery takes about 5 minutes but with pre-operative preparations, your entire visit may take an hour or two.
Following your procedure, you will be given additional eye drops, and your eye may be shielded for protection. Your vision will probably be a little blurry at first. Please arrange for someone to drive you home. You should relax for the rest of the day. You may experience some discomfort, but this is usually alleviated with an over-the-counter pain reliever. Some people experience sensitivity to light, and watering or swelling of their eyes for a few days following the procedure.
Everyone heals differently, but most patients resume normal activities the next day. Some patients see a dramatic improvement in their vision within the first day. For others, vision may be blurry for several weeks.
Limbal relaxing incisions have relatively few risks and are not typically associated with glare or starbursts, as often occurs with direct corneal incisions (RK and AK). The procedure is completed in a few seconds after numbing the eye with anesthetic drops and there is usually little if any post-operative discomfort. Furthermore, the cornea is usually stable within 2 to 3weeks, indicating that visual fluctuations have typically resolved by that time interval.
For patients who desire an even greater level of precision of their astigmatism correction, LASIK is an appropriate choice either as a standalone procedure or following cataract surgery. Dr. Seibel and his staff will be happy to discuss these options with you.