[Cataract operation after silicone oil surgery. Oil drop adhesion to silicone lenses]

To investigate the phenomenon of oil droplet formation on silicone IOLs with regard to visual acuity, intraocular pressure (i.o.p.), and clinical findings.

Retrospective study (january 1995 to December 1996) on 78 patients who underwent cataract surgery after previous complex silicone oil surgery for PVR-complicated rhegmatogenous retinal detachments (64) or proliferative diabetic retinopathy (14). Follow-up after cataract surgery 15.5 (7.55) months. PMMA IOLs were used in 50 and silicone IOLs in 19 cases. Nine patients did not receive an intraocular lens. The groups were divided up further with regard to secondary YAG capsulotomies and oil explanations. Before cataract operation, one or two (1, 23) complex vitreoretinal operations were performed with case-dependent additional retinal laser coagulations. For statistical analysis the two-sided t-test and/or Welch's test were applied.

The preoperative mean visual acuity (VA) was significantly better (P < 0.0001) in the group treated with PMMA IOLs than in the one without IOL (VA with PMMA 0.093, silicion 0.075, without IOL 0.026). Significant improvement of VA after surgery was found with PMMA Implantation after YAG capsulotomy without silicone oil explantation (P = 0.0003). Visual improvement was best in PMMA IOLs after YAG capsulotomy with the remaining silicone oil (0.076), followed by the group without IOL implantation (0.063). In the groups with PMMA IOLs/YAG/oil explantation, a rise in VA of 0.06 was achieved, and in silicone IOLs/YAG/oil explantation, the rise in VA was 0.002. No statistically significant differences were found in postoperative mean VA. Preoperative intraocular pressure (i.o.p.) was lower in the PMMA group than in the group without IOL (P = 0.0447). No significant differences in the postoperative IOPs were found between groups, but in the PMMA/YAG/oil in situ group, IOP decreased significantly after surgery (P = 0.0142). Maculopathies were found in the PMMA group in 31, in the silicone group in 16, and in the group without IOL implantation in 7 cases. Optic atrophy was found in the PMMA group in 8, in the silicone group in 4, and in the group without IOL implantation in 3 cases.

In all groups silicone oil surgery and secondary cataract operation with or without YAG capsulotomy and oil explantation achieved stable or slightly improved mean VA with significance in PMMA IOL implantation/YAG capsulotomy without oil explantation. Comparing PMMA IOLs/YAG/oil explantation and silicone/YAG/oil explantation, an advantage in the PMMA groups was found. However, because of large interindividual differences (large standard deviations) there was no statistical significance. Thus, in this series the phenomenon of silicone droplet adhesion on silicone IOLs is secondary to the influence of retinal pathologies.