Technique changes risk factors

However, by maintaining awareness of the changes in the intraocular environment and adopting modifications in their technique, surgeons performing laser cataract surgery can reduce or even eliminate the likelihood of experiencing a case of capsular block syndrome, said Dr Lawless, medical director, Vision Eye Institute, Chatswood, New South Wales, Australia.

Dr Lawless reviewed the development of capsular block syndrome in two eyes that were among the first 50 laser cataract surgery cases performed at the Vision Eye Institute, Sydney, Australia. Both cases occurred on the same day in the hands of a colleague who Dr Lawless described as an experienced and skilled cataract surgeon.

"Different gas patterns are produced within the lens when using the femtosecond laser for capsulotomy and lens fragmentation, but when the nucleus is dense, the gas tends to accumulate behind the nucleus," Dr Lawless said. "The perfect capsulotomy created using the femtosecond laser results in a tight barrier to fluid egress during hydrodissection. These conditions, together with the fact that hydrodissection is usually done quite vigorously in eyes with a dense nucleus, create a perfect storm for blowing out the posterior capsule.

"After these two events, we fully investigated the complications and reported them to the FDA and Australian regulatory agency authorities," he said. "We have also reported our experience in the literature1, and we hope that by reporting on the complication it won't happen to other surgeons. It has not happened in our hands since these first two cases."

Dr Lawless presented a video from the first case that showed the lens fragmentation was performed with what had become routine settings so that its limits were 1 mm anterior to the posterior capsule and 0.5 mm posterior to the anterior capsule.

After the patient was transferred to the operating room, the corneal incisions were opened, ophthalmic viscoelastic device (OVD) was injected into the anterior chamber, which deepened normally, and the capsular disc was removed. There was no evidence of an anterior capsular tear.