Iridotomy can ease cataract surgery in patient with narrow angles

Iris likely to remain in good position within anterior chamber if procedure is performed preoperatively.

With the advent of small-incision cataract surgery, the cataract surgeon can now control the anterior chamber depth. This technology allows the cataract surgeon to safely work in an eye with a shallow anterior chamber, but it has no effect upon the anterior chamber angle, which can sometimes lead to unexpected consequences.

Specifically, in the patient presenting with a narrow to closed anterior chamber angle, the surgeon may be surprised to discover that the iris will spontaneously present in the wound, which can be rather difficult to reposition within the eye.

In the attempt to reposition the iris within the anterior chamber, the surgeon may inadvertently tear or rip the iris, resulting in function loss of the iris and more difficulties during the cataract surgery.

Unfortunately, the surgeon may end up with a cosmetically poor result with subsequent visual problems of photophobia and monocular diplopia.

As an alternative, the surgeon may attempt to perform a surgical iridectomy when the iris presents in the wound. This procedure may result in an iridectomy that is larger than what the surgeon had hoped for, again leaving the patient with visual problems after cataract surgery.

Another alternative is the use of mannitol given intravenously during cataract surgery to try to deepen the anterior chamber. Unfortunately, many of our elderly patients have cardiovascular or urological problems, such as congestive heart failure or an enlarged prostate, which would preclude us from using this medication.

Preop iridotomy

In light of all of these problems, it has been my belief that if this issue of a narrow angle can be addressed before cataract surgery, the actual surgery may go a lot easier for both the surgeon and the patient.

Specifically, it has been my observation that when the patient with a narrow angle undergoing cataract surgery has a patent laser iridotomy or surgical iridectomy, the surgery seems to go a lot easier with fewer problems.

With this in mind, I performed laser iridotomy preoperatively on a series of patients presenting for cataract surgery with shallow or narrow anterior chamber angles.

Once the laser iridotomy had been successfully performed, the anterior chamber angle was observed to spontaneously deepen in all of these patients.

During cataract surgery on these patients, the iris was observed to remain in excellent position within the anterior chamber at all times, allowing successful cataract surgery to be done.

Based upon this experience, I strongly recommend that any patient presenting with a small, hyperopic eye for cataract surgery be given special consideration. This should include any patient requiring an IOL implant of +25 D or higher at the time of cataract surgery.

In these patients, we suggest that careful gonioscopy be done to look for angle closure or for a compromised anterior chamber angle.

In those patients who do present with a compromised anterior chamber angle, we strongly recommend that a laser iridotomy be performed prior to cataract surgery. We have found that a laser iridotomy performed with either the argon or the YAG laser is acceptable.

Location critical

It is critical where the laser iridotomy is done in the eye. In my patients, I prefer a temporal approach to cataract surgery and will perform the laser iridotomy in the superior nasal quadrant.

In all cases, I recommend that, if possible, the laser iridotomy not be performed in the same quadrant where the surgical wound will be made for the cataract surgery and that the iridotomy be performed in a superior quadrant under the eyelid to minimize glare after cataract surgery.

A laser iridotomy performed as described here has not presented with any problems either during the surgery or the subsequent postop period in any of our patients.

Cataract surgery in the small, hyperopic eye can be rather challenging under the best circumstances. For these reasons, we suggest that the cataract surgeon perform gonioscopy in these patients. In the patient observed to have a compromised anterior chamber angle, a laser iridotomy should be done prior to cataract surgery.

For Your Information:

• Robert M. Mandelkorn, MD, is the director of the Department of Veteran Affairs OPC Eye Clinic. He can be reached at 3033 Winkler Ave. Extension, Fort Myers, FL 33916; (239) 939-3939; fax: (239) 267-3759. Dr. Mandelkorn has no financial interest in the products or devices mentioned in this article.