Emulsification tendency of silicone-phenylsilicone copolymer

Mechanical energy from intraocular instruments cause emulsification of silicone oil

AIM

The complications of intraocular silicone oil include emulsification, which may lead to vision-threatening disorders such as keratopathy, secondary glaucoma and retinopathy. The authors study the effect of mechanical energy from surgical instruments on the emulsification of silicone oil.

METHODS

Three different handpieces (phacofragmentation, phacoemulsification, high-speed vitrectomy) were placed at the interface of balanced salt solution and silicone oil (1000 and 5000 cst, 200 fluid; Dow Corning). The phacofragmentation handpiece was evaluated over different ultrasound powers and duration. Emulsification was quantified with phase-contrast microscopy and manual counting of digital photographs by a masked examiner. In addition, phacoemulsification was performed in the anterior chamber of a human ex vivo eye with full-fill silicone oil.

RESULTS

Emulsification increases with higher phacofragmentation power and duration and is greater for 1000 cst silicone oil. Emulsification of silicone oil occurs with phacoemulsification and high-speed vitrectomy handpieces.

CONCLUSIONS

The energy from surgical handpieces is sufficient to result in silicone oil emulsification.

FOURIER TRANSFORM INFRARED AND 1H NUCLEAR MAGNETIC RESONANCE SPECTROSCOPIC FINDINGS OF SILICONE OIL REMOVED FROM EYES AND THE RELATIONSHIP OF EMULSIFICATION WITH RETINOTOMY AND GLAUCOMA

PURPOSE

To investigate whether structural changes occur in silicone oil that has been left in the eye for different periods and to research the relationship of emulsification with the time during which silicone oil is left in the eye, glaucoma, and wide relaxing retinotomy.

METHODS

Samples of silicone oil were randomly removed from the eyes of 22 patients. Gel permeation chromatography (GPC) and spectroscopy were used to identify any changes in the silicone oil. The relationship between spectroscopically determined emulsification with time spent in the eye, glaucoma, and wide relaxing retinotomy was investigated statistically.

RESULTS

GPC revealed that no change was found in the 1,000-centistoke silicone oil model after it had been removed from the eye. Spectroscopy identified absorption peaks belonging to water in addition to those belonging to the functional groups. The relationships between emulsification and time spent in the eye and glaucoma were found to be statistically insignificant, while that between emulsification and wide relaxing retinotomy was statistically significant.

CONCLUSION

Intravitreally applied silicone oil undergoes no structural change. Wide relaxing retinotomy constitutes a risk factor for silicone oil emulsification, which can occur earlier than expected and before it can be observed clinically.