Sealed capsule irrigation device helps prevent PCO development in small eyes

Stockholm, Sweden-The Perfect Capsule (Milvella), a sealed capsule irrigation device, seems to be very useful in very small eyes for preventing posterior capsular opacification (PCO), according to Maria Kugelberg, MD, PhD.

This study, conducted in 4-week-old rabbits, showed that the device-when irrigated with 5-fluorouracil (5-FU)-almost completely eliminated the development of PCO.

"The Perfect Capsule is a device that was designed to prevent PCO," Dr. Kugelberg explained.

"The rationale behind the study is that in pediatric cataract surgery there is a huge problem with after-cataract or PCO," said Dr. Kugelberg, a resident in ophthalmology at St. Erik's Eye Hospital, Stockholm, Sweden. "Many studies have suggested that it is advantageous to perform a posterior capsulorhexis and an anterior vitrectomy. However, in very small children this may not be sufficient. They may need a secondary intervention to remove the after-cataract."

The silicone device is about 7 mm with an inner diameter of about 5 mm. This necessitates the creation of a capsulorhexis of about 3.5 to 4.5 mm, she said.

"The [device] is applied to the anterior capsulorhexis, a vacuum is created, and the device is sucked onto the anterior capsulorhexis," Dr. Kugelberg said. "Irrigation through a channel is then possible without damaging the rest of the eye."

Thirty rabbits were used in this study and the animals were divided into three groups: in the first group irrigation was performed with distilled deionized water; in the second group with balanced salt solution (BSS) as a control; and in the third 5-FU 50 mg/ml, an antimetabolite used in ocular surgery.

The eyes were left aphakic and the investigators looked at the after-cataract clinically at 4 weeks, from retroillumination photographs at 6 weeks, and histologically after the animals were killed at 6 weeks, Dr. Kugelberg explained.

The investigators also were interested in the thickness of the capsule.

"It has been suggested that the capsule would not survive if it was devoid of lens epithelial cells," Dr. Kugelberg said. "The capsule thickness is a rough estimate of measuring the status of the capsule."

The capsule thickness was measured using the computer program AxioVision (Carl Zeiss Meditec).

"We measured the capsule thickness in the three study groups and could not find a significant difference among the three groups," Dr. Kugelberg said. However, further studies are on-going, using electron microscopy to study possible changes in the structure of the capsule.

Investigators were able to apply the device in all 30 eyes, despite the small size of the eyes. The system was sealed in all eyes. The distilled water irrigation did not prevent PCO satisfactorily and there was no difference between this group and the group of eyes irrigated with BSS.

"The 5-FU in the concentration of 50 mg/ml prevented after-cataract satisfactorily," she said. "The capsules in the bag were almost totally clear of PCO. The 5-FU group had significantly less after-cataract then the other two groups (p < 0.05)."