Ultrasound biomicroscopy in silicone oil-filled eyes

Characteristics of Silicone Oil Emulsification After Vitrectomy for Rhegmatogenous Retinal Detachment: An Ultrasound Biomicroscopy Study

Purpose: To investigate the characteristics of silicone oil (SO) emulsification after vitrectomy for rhegmatogenous retinal detachment (RRD) and possible correlations with clinical factors.

Methods: Patients who underwent primary pars plana vitrectomy with SO injection for RRD followed by SO removal at the Eye and ENT Hospital of Fudan University between January 2016 and January 2020 were included. Ultrasound biomicroscopy (UBM) images of the anterior segment were taken before SO removal. Eight signs of SO emulsification in the UBM images were graded as 1 (present) or 0 (not present) and the grades for all signs in each eye were summed. Correlations between SO emulsification grade and clinical factors were determined.

Results: A total of 118 patients (118 eyes) were enrolled in this study. Emulsified SO particles were found in all 118 eyes (100%). The eight signs were more frequently detected in the superior part of the eye. The mean total SO emulsification grade was 19.99 ± 12.98 (range: 1–36). Younger age and male (both P < 0.05) were associated with higher total SO emulsification grade. Patients with intraocular pressure (IOP) > 21 mmHg or the use of antiglaucoma medications at the time of SO removal had a higher total SO emulsification grade, were younger, and were more frequently male (all P < 0.05) than patients without ocular hypertension.

Conclusions: UBM could play an important role in the diagnosis and grading of SO emulsification. Younger patients and males are more prone to SO emulsification, which may lead to elevated IOP.

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.