Prone position ultrasonography in silicone filled eyes

Abstract

Purpose: To evaluate the efficacy of a new technique of prone position ultrasonography in cases with silicone filled eyes. Methods: Forty patients with prior pars plana vitrectomy and silicone oil instillation referred to a tertiary eye care centre were the subjects of this study. A prospective clinical trial was undertaken to evaluate the efficacy of prone position ultrasonography in addition to routinely performed supine position ultrasonography in these patients. The technique was undertaken by 2 independent observers and compared with the findings by indirect ophthalmoscopy or surgical results. Interobserver variability was also calculated. Results: Two spikes were observed in supine position corresponding to the intravitreal silicone oil surface and the sclera, whereas a single spike corresponding to the sclera was observed in prone position. Supine position ultrasonography yielded a diagnostic accuracy of 61.8% which inreased to 96.7% when the procedure was supplemented with prone position ultrasonography. Specificity increased from 75 to 100% by the addition of this adjuvant procedure, however, with no significant difference in the interobserver variability ('K' = 0.67 Vs 'K'= 0.62). Conclusion: Prone position ultrasonography is a useful adjunct to the routinely performed supine position ultrasonography in silicone filled eyes and increases the diagnostic yield.