The Effect of Subtenon Injection of Methylprednisolone Acetate on the Breakdown of Blood Retinal Barrier After Cryotherapy

Using computerized vitreous fluorophotometry (VFP, Fluorotron™), we examined the effect of cryotherapy on the blood retinal barrier (BRB) and the effect of subtenon injection of methylprednisolone acetate (DepomedrolⓇ). In experiment 1, the right eyes of the 13 pigmented rabbits were treated with heavy cryotherapy after baseline VFP readings. The freezes were applied at 6 places in each quadrant around the equator area in two rows, a total of 24 places circumferentially. The left eyes were reserved as controls. In 6 rabbits (cryo with steroid group), DepomedrolⓇ 10 mg of Depomedrol was injected into subtenon space after cryotherapy. The other 7 rabbits were treated with cryotherapy only (cryo only group). The VFP readings were taken 1, 3, 5, and 7 days, 2, 3, 5, and 7 weeks after cryotherapy. Cryotherapy increased the breakdown of BRB significantly. The peak VFP readings were obtained 5 days after cryotherapy in the cryo only group and 7 days after cryotherapy in the cryo with steroid group. In the cryo only group, the severity of the breakdown of BRB was higher than in the cryo with steroid group, and the increased VFP readings could not be normalized until 7 weeks after cryotherapy.