[Long-term use of silicone oil: indications and tolerance]

Emulsification of Silicone Oils: Altering Factors and Possible Complications-A Narrative Review

Background: Endotamponade of the vitreous body with silicone oil is a common procedure, being the basis of many vitreoretinal surgeries. However, emulsification may happen, which is a clinically relevant adverse event of silicone oil use. Methods: This review provides a thorough analysis of the emulsification process. It focuses on describing factors affecting this event as well as its possible subsequent complications. Results: The viscosity of silicone oil, the duration of emulsification, the status of the lens and many other factors have an influence on the onset and intensity of emulsification. This phenomenon carries several risks for operated eyes such as increased intraocular pressure, keratopathy or structural changes to the retina. Conclusions: The use of modern imaging techniques, especially optical coherence tomography, enables faster detection of the emulsification process. This allows for an adequate clinical response and more accurate follow-up of the patient.

An ex vivo headspace gas chromatography-mass spectrometry method for the determination of short-chain siloxanes in silicon oil tamponades used in ophthalmic surgery

Being able to facilitate retinal reattachment by preventing water migration into the subretinal space, silicone oils are widely used as long-term intraocular tamponade to treat cases of retinal detachment. Various commercial tamponades constituted by linear polydimethylsiloxane polymers with different molecular weights and cyclic impurities are available. In this study, for the first time, an untargeted headspace-gas-chromatography-mass spectrometry (HS-GC-MS) method was developed to identify low-molecular weight contaminants in three different types of silicone oil tamponades, namely Siluron 2000, RS-OIL ECS5000 and Densiron Xtra. Both commercial and post-operative tamponades were analysed to screen for the different classes of compounds present in the samples. The most abundant classes were short-chain siloxanes, fluorinated compounds, and hydrocarbons. To quantify the siloxanes present in the samples, a targeted HS-GS-MS was optimized using a central composite design and validated according to guidelines for bioanalytical methods. Lower limits of quantification in the low μg/L range, good precision with RSD% < 12% and accuracy with recovery rates in the 81 ( ± 7) - 96 ( ± 4) % range were achieved. Short-chain siloxanes were quantified in both commercial and post-operative tamponades, being the RS-OIL ECS5000 characterized by the highest concentration levels of the investigated analytes. By contrast, Densiron Xtra tamponades showed the lowest amount of short-chain siloxanes, observing a general decrease in their concentration levels according to the residence time in the eyes.

COHORT SAFETY AND EFFICACY STUDY OF SILURON2000 EMULSIFICATION-RESISTANT SILICONE OIL AND F4H5 IN THE TREATMENT OF FULL-THICKNESS MACULAR HOLE

Silicone oils that are easier to inject and remove with smaller-gauge instruments, and in surplus have a reduced propensity for emulsification, offer great potential in vitreoretinal procedures. Safety and efficacy of Siluron2000 silicone oil in treatment of full-thickness macular hole were compared with those of Siluron5000 oil. We also assessed the efficacy of perfluorobutylpentane in removing emulsified oil droplets from the eye using ultrasound imaging.

To evaluate safety and efficacy of using Siluron2000 silicone oil in the treatment of full-thickness macular hole by comparing its propensity to emulsify with emulsification of the “gold standard” Siluron5000, and to assess safety and efficacy of F4H5 (perfluorobutylpentane) in removing emulsified oil droplets from the eye.

Visual outcome after removal of silicone oil in patients undergoing retinectomy for complex retinal detachment

AIM

To evaluate the functional outcome after removal of silicone oil (ROSO) in patients undergoing retinectomy for complex retinal detachment.

METHODS

We performed a retrospective case note review of patients who underwent ROSO after retinectomy for complex retinal detachment. Patients with less than 6mo follow up and recurrent retinal detachment following ROSO were excluded.

RESULTS

Thirty-six patients were included. The mean best corrected visual acuity (BCVA) pre-ROSO was 1.13 logMAR (SD 0.5). The mean BCVA 3mo following ROSO was 1.16 logMAR (SD 0.53), 6mo following ROSO 1.13 (SD 0.63), and 12mo following ROSO 1.18 (SD 0.69). At 12mo after ROSO, the BCVA improved in 38.9% of patients, remained unchanged in 25%, and deteriorated in 36.1%, although there was no statistical significant difference in BCVA after ROSO at 3, 6 and 12mo (P=0.93). The size of retinectomy ranged from 15° to 270° (SD 53) and did not influence the visual outcome (P=0.11).

CONCLUSION

There was no statistically significanT difference in BCVA between pre- and post- ROSO following retinectomy for complex retinal detachment. There was no statistical difference in visual outcome related to the size of the retinectomy.

[Complications of silicone oil tamponade]

Silicone oil tamponade is used for the management of complicated retinal detachment. Patients should be closely monitored as many complications may occur with intraocular silicone oil. Short-term complications include temporarily increased intraocular pressure and anterior segment inflammation. Long-term complications include cataract, emulsification, ocular hyper- or hypotension, keratopathy and retinal redetachment associated with proliferative vitreoretinopathy.