THE INCIDENCE OF CORNEAL ABNORMALITIES IN THE SILICONE STUDY - SILICONE STUDY REPORT-7

Objective: To determine factors that were prognostic of corneal abnorm alities in eyes following surgery for severe proliferative vitreoretin opathy. Design: Subgroup analysis of the Silicone Study. Settings: Com munity and university-based ophthalmology clinics. Materials: Eyes wit h attached maculae at the 24-month follow-up examination that did not have a preexisting corneal abnormality. Interventions: Vitrectomy surg ery with long-acting gas or silicone oil. Outcome Measures: Epithelial and/or stromal edema, corneal opacity and/or previous corneal transpl ant. Results: The incidence of corneal abnormalities at 24 months was 27% and did not differ significantly between treatment groups. Prognos tic factors were preoperative aphakia or pseudophakia (P=.003), preope rative iris neovascularization (P=.006), reoperation (P=.001), the abs ence of a fluid/gas exchange (P=.03), corneal touch by silicone oil (P =.02), and the presence of aqueous cells (P=.009) or aqueous flare (P= .08). In a multivariate analysis, independent prognostic factors were iris neovascularization (relative risk [RR]=13.1), aphakia or pseudoph akia (RR=3.0), postoperative aqueous flare (RR=5.4), and reoperations (RR=3.4). Corneal abnormalities were correlated with poor visual acuit y and hypotony (P<.001). Conclusions: To our knowledge, this is the fi rst study to document that the incidence rates of corneal abnormalitie s are equivalent between oil and gas. The incidence of corneal abnorma lities in gas-filled eyes was higher than expected, and remained high in oil-filled eyes, despite the use of an inferior iridectomy. Success ful surgical repair of the retinal detachment with a single operation, and prevention and early management of corneal touch by silicone oil should help to prevent corneal abnormalities. If rubeosis iridis or se vere aqueous flare is present, preoperative treatment with intense top ical and possibly periocular steroids might reduce inflammation, which might mediate corneal damage.