Silicone Oil Affects Visual Outcomes of Complicated Retinal Detachment Surgery

In patients who undergo complicated retinal detachment surgeries employing a silicone oil tamponade, strong visual outcomes are more likely if the patient is pseudophakic at the 3-month postoperative visit and has good visual acuity (VA) before silicone oil removal (SOR), according to a study published in Clinical Ophthalmology. The study also shows that while pars plana vitrectomy and silicone oil (SO) tamponade can achieve an anatomically attached retina in most cases, functional success remains much lower. 

Medical charts for 182 eyes of 174 individuals (mean age, 50.7±11.8) years, list types of complex RDs as rhegmatogenous (76.9% of participants), tractional (15.9%), and combined (7.1%). Participants underwent pars plana vitrectomy (PPV) with tamponade, followed by SO removal between January 2012 and October 2021. Removal suitability was indicated by reattachment at 3 to 6 months, or complications from SO. 

At 3 months after SO removal, 90.66% of eyes attained anatomical reattachment, and 57.14% achieved functional success of at least 20/200. For eyes that maintained attachment after SO removal, 63.03% achieved good VA. In univariate analysis, factors that influenced visual results either way comprised best-corrected visual acuity (BCVA) before SO removal (P <.001), BCVA prior to initial surgery with tamponade (P =.001), pseudophakia at final visit (P =.002), only a single primary procedure (P =.002), added endolaser treatment during SO removal (P =.005), dual SO removal with cataract surgery (P =.038), and macula-on RD (P =.047).

“Visual impairment due to retinal detachment is alleviated to a certain degree after the primary PPV procedure as the retina reattaches with SO tamponade, depending on the presence of macula on or off. Optical properties of SO in the vitreous result in high refractive errors which preclude good visual results,” the researchers report. “The SOR procedure improves visual acuity via SO removal and subsequent cataract surgery with intraocular lens (IOL) placement further improves visual outcomes. Therefore, visual acuity before SOR and pseudophakia status may be predictors for good visual outcome after SOR.”

Multivariate analysis distinguished that good visual outcome was associated with BCVA before SO removal (P <.001) and pseudophakia at final follow-up (P =.021). Conversely, added endolaser treatment (P =.004) and circumferential peripheral retinopexy (P =.037) were related to VA worse than 20/200. There were fewer instances of retinopexy and endolaser, and the investigators speculate poorer outcomes resulted because these interventions were used for challenging detachments such as those caused by severe proliferative vitreoretinopathy.

The most frequent complication during SO tamponade was intraocular pressure (IOP) higher than 21 mm Hg, experienced in 46.2% of eyes, although it was effectively managed with medication. Researchers suggest removal of SO may not sufficiently alleviate high IOP because SO drops could remain in the trabecular meshwork. Other adverse events noted were re-detachment in 9.07% of eyes, hypotony for 6.6%, and bullous keratopathy, 1.7%.

Previous research indicates that cataracts arise in 49% to 100% of eyes with longer tamponade use, but the current investigation suggests combined phacoemulsification with SO removal may be made more difficult by the estimation of IOL power. Also, the present multivariate model did not prove significance for this dual surgery (P =.105).

Limitations of this paper involved potential participants being excluded due to limited records, lack of data for macular or choroidal thickness, and possible underestimation of eyes with good final VA due to the nature of referrals from primary hospitals to the tertiary eye center. This study is first to report predictors other than pseudophakia that may impact acuity after complicated detachments.