Correlation between quantity of silicone oil emulsified in the anterior chamber and high pressure in vitrectomized eyes

Purpose: To assess the existence of any correlation between the quantity of silicone oil emulsified in the anterior chamber and the incidence of high intraocular pressure in vitrectomized eyes. Methods: Forty-nine eyes of 49 patients underwent vitrectomy with silicone oil injection as an adjuvant procedure. At the time of observation, between September 1999 and September 2000,13 eyes (26.5%) were phakic; 23 eyes (47%) were pseudophakic; and 13 eyes (26.5%) were aphakic. Ultrasound biomicroscopy, slit-lamp biomicroscopy, and gonioscopy were performed to quantify the presence of silicone oil emulsified in the anterior chamber. Results: The 13 phakic eyes did not have a high intraocular pressure. In 8 of,the 13 eyes, ultrasound biomicroscopy detected only scarce oil emulsification in the anterior chamber (0.304 mm); in 5 of the 13 eyes, gonioscopy and ultrasound biomicroscopy did not detect anterior chamber oil emulsification. Fourteen of 23 pseudophakic eyes had a high intraocular pressure; of these, ultrasound biomicroscopy, detected an abundant amount of anterior chamber oil emulsification (0.922 mm). Nine of 23 pseudophakic eyes did not have a high intraocular pressure; of these, ultrasound biomicroscopy detected little anterior chamber oil emulsification (0.209 mm). The 13 aphakic eyes had a high intraocular pressure; of these, ultrasound biomicroscopy detected an abundant amount of anterior chamber oil emulsification (0.795 mm). The coefficient of correlation for the measurements obtained was 0.98 (F = 62.3, P = 0.05; t = 11.1, P = 0.001). Conclusion: This study showed a high correlation between the incidence of high intraocular pressure and the quantity of emulsified silicone oil in the anterior chamber