Vitreous prolapse through the scleral wound in 25-gauge transconjunctival vitrectomy

To examine the effectiveness of excising peripheral vitreous until the cannula tip is exposed to prevent vitreous prolapse through the scleral wound in 25-gauge transconjunctival vitrectomy.

Twenty-five-gauge vitrectomy was performed in 60 consecutive eyes. Peripheral vitrectomy was conducted until the cannula tip was exposed in 30 eyes and with conservation of the vitreous around the cannula in 30 eyes. Vitreous prolapse through the scleral wound was examined using a suction stick.

Vitreous prolapse through the scleral wound was transparent, fine and short, and detectable only with the suction stick. The incidence of vitreous prolapse through the scleral wound was 0% (0 of 30 eyes) when peripheral vitreous was excised until the cannula tip was exposed, and 20% (6 of 30 eyes) when the vitreous around the cannula was conserved, with a significant difference between two groups (p=0.0237). In two of six eyes with vitreous prolapse, the scleral wound was open, but there was no leakage of intraocular fluid and normal ocular pressure was maintained.

If peripheral vitrectomy is performed without excising the vitreous surrounding the cannula, there is a 20% risk of the vitreous prolapsing through the scleral wound. Vitreous prolapse through the scleral wound is difficult to detect because it is transparent, fine and short, and there is no intraocular fluid leakage. Therefore, detecting vitreous prolapse with a suction stick and appropriate intervention are important for preventing endophthalmitis.