Is there a risk of retinal detachment after YAG capsulotomy?

by Lisa B. Samalonis

Practices can determine if they are at risk and inform patients accordingly.
Cataract surgeons say that while the incidence of retinal detachment after Nd:YAG capsulotomy is low, surgeons can determine their individual practice's rate then decide if they want to inform patients of a risk of retinal detachment after capsulotomy, said Richard J. Mackool, MD, director of the Mackool Eye Institute, Astoria, N.Y.
Dan Eisenberg, MD, in practice in Las Vegas, advised ophthalmologists to analyze the issue scientifically to find the native rates in their practices. He said that the rate equals the event per unit time per population density, age adjusted (if needed).

"We need the rate of retinal detachment [RD] in phakic eyes, the rate of RD in postcataract eyes, and the rate of RD in postcataract post-YAG capsulotomy eyes," Eisenberg said.

"With the appropriate rates, you can calculate an odds ratio [the relative risk of one rate vs. another] and then, only if the odds ratio were significantly above 1, could you begin to declare an increased risk," he said.

The pathophysiology of retinal detachment is abnormal vitreoretinal traction. "Because this likely is present on its own, there is likely no increased risk of RD after cataract extraction or capsulotomy. Certain anatomic changes may speed up the process, but it was a natural process that was already in motion. The increased risk, if any, would not be the event but the time course," he said. "Therefore, I do not warn my patients of risk of RD, as I do not believe it is in any way due to the capsulotomy."
Eisenberg does inform patients that there is a rare chance of the lens shifting position, which may require additional surgery.

Lack of literature
Mackool performed a study that compared the RD rate in approximately 400 YAGs with the same number of eyes undergoing cataract extraction by him, but not yet requiring YAG capsulotomy. Both groups had the cataracts removed routinely, with intraocular lenses placed in the capsular sac at the same time. They also were followed for similar lengths of time.

"We found no difference in RD rate between the two groups with a minimum follow-up time of 1-year post-YAG," he said.

The results of the study are unpublished in peer-reviewed literature. However, Mackool refers to them in his practice's YAG consent form. "I did this because I wanted to accurately inform my patients about the RD risk after YAG when the cataract extraction and YAG procedure were performed by us," he said.

Mackool said that the results are valid only for his patients and that extrapolation to other techniques of cataract extraction or IOL placement is not possible. However, it is relatively simple for any surgeon to study his/her own patients during a 3-year period and to determine what the risk is for their patients, he added.

Howard V. Gimbel, MD, Gimbel Eye Centre, Calgary, Alberta, Canada, studied the incidence of retinal detachment following YAG capsulotomy after cataract surgery in a study that was published in the Journal of Cataract and Refractive Surgery in 1992.

In a retrospective study, the researchers reviewed 218 consecutive YAG laser posterior capsulotomies performed at the center between June 1987 and November 1989 for the incidence of RD following treatment.

Matched controls were found for 198 YAG cases. The median postsurgical follow-up for the YAG cases was 49.5 months and 50 months for the controls. The median time
between cataract extraction and YAG laser posterior capsulotomy was 24.8 months.

The median follow-up after YAG was 24.2 months.
Two of the 198 YAG cases (or 1%) and one of the 198 controls (or 0.5%) had RD. In the YAG cases, RD occurred 54.8 and 36.5 months after cataract surgery. In the control cases, RD occurred in 51.8 months after cataract surgery. Retinal detachment occurred at 15 and 17 months after YAG capsulotomy.

"We feel that the surgical techniques of continuous circular capsulorrhexis and in-the-bag IOL placement reduce the risk of RD following Nd:YAG posterior capsulotomy," Gimbel said.

Samuel Masket, MD, clinical professor, University of California, Los Angeles, Jules Stein Eye Institute, said that no recent literature regarding the rate of retinal detachment after YAG capsulotomy exists.

"Those groups that have very large volumes of surgeries indicate [that the] rate of RD is nil following laser capsulotomy. The problem is that these data do not exist in literature," he said.

Masket said that this information can be difficult to compile, because many physicians have referral-based practices. The patients often come from geographically distant areas and are hard to adequately follow for study purposes.

Assessing risk
Whether there has already been a posterior vitreous detachment (PVD) is an important factor to determining if the patient is at risk for RD, Masket said. "If the vitreous has undergone contraction, detached prior to cataract surgery or … laser capsulotomy, then the risk of retinal tear, in my view, goes down significantly. When I evaluate a patient for either cataract surgery or laser capsulotomy, one of the most important factors is the status of the vitreous," he said.

Studies have shown that the risk of RD is significantly greater in young men who have elongated myopic eyes. "In dealing with such a patient, with axial length greater than 26 mm, I do talk to those patients about the risk of detachment. In their case, if there has already been a PVD or a posterior vitreous detachment or separation, the risk is significantly low," he said.

"My view is that the risk of RD following capsulotomy is probably quite similar to the risk of RD following cataract surgery, and that that risk is greatly reduced if the patient has already experienced a posterior vitreous detachment. Vitreous contraction, to me, is the greatest risk for retinal detachment," Masket said.

Informed consent issues
Some physicians inform potential YAG capsulotomy patients about the possibility of RD after YAG. While many surgeons agree that there is no increased risk, many believe there is and would be willing to say so, said Keith Kellum, MD, clinical assistant professor, Louisiana State University, New Orleans, and in practice in Houma, La. "I tell potential patients there is a risk of it, although I don't really believe it is significant. Just like I tell my cataract patients there is even a risk of them losing their entire eye from cataract surgery. Theoretically, that is true, but I don't really feel that it is a true risk."

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