SEQUESTRATION AND PERSISTENCE OF METHOTREXATE BUBBLES WITHIN SILICONE OIL TAMPONADE AFTER PARS PLANA VITRECTOMY

PURPOSE: To describe the occurrence of methotrexate (MTX) bubbles after serial intravitreal injections in silicone oil (SO)-filled eyes undergoing repair for retinal detachment and to evaluate outcomes. METHODS: In this retrospective cohort study, nine eyes of nine patients received pars plana vitrectomy with SO tamponade and intravitreal MTX injection during surgery and was scheduled for postoperative series per gain understanding against RD protocol. MTX bubbles were identified by dilated fundus examination and ultrawidefield imaging. Relevant clinical and imaging parameters were collected. RESULTS: MTX bubbles were noted in six of nine eyes at a mean of 29.7 days (range: 7-58) after a mean of 3.8 injections (range: 2-6). Mean baseline best-corrected visual acuity was 1.5 logMAR (Snellen equivalent: 20/600), worsening to 1.7 logMAR (Snellen equivalent: counting fingers) at bubble detection. Four of the six eyes with bubbles were eventually found to have emulsified SO. All eyes maintained anatomical reattachment without evidence of toxicity throughout a mean follow-up of 200.7 days (range: 105-241). CONCLUSION: Early MTX bubble formation in SO-filled eyes likely reflects immiscibility of the aqueous drug solution and SO. Despite maintained reattachment, sequestration may alter drug distribution. Further research is needed to elucidate whether MTX is a risk factor for SO emulsification.