Identification of breaks in choroidal coloboma eyes with retinal detachment using subretinal trypan blue injection

Abstract

Abstract Purpose To describe the use of subretinal trypan blue to localize retinal breaks during vitrectomy for rhegmatogenous retinal detachment in choroidal coloboma eyes. Methods Trypan blue 0.03% was injected subretinally through a retinotomy superonasal to optic disc in 108 choroidal coloboma eyes in which no breaks could be identified pre‐ or intra‐operatively outside the coloboma margins. Eyes were rotated to evenly spread the dye subretinally and plume of trypan blue into the vitreous cavity was used to locate the breaks. Communication between breaks in the intercalary membrane (ICM) and coloboma margin was also studied. Results Eighty six eyes had breaks within the coloboma margins only whereas 7 eyes had breaks within as well as outside the coloboma. In 7 eyes breaks were seen in peripheral retina alone and no breaks could be found in 8 eyes even intra‐operatively. In all eyes with break inside the coloboma there was a single communication at its margin between the detached retina outside the coloboma and the break in ICM through which trypan blue entered vitreous cavity. Mostly it was in the infero‐nasal or temporal quadrant outside the inferior vascular arcade. Conclusion Majority of retinal detachments that involve the coloboma were caused by breaks within the ICM. Moreover there is a small defect at the coloboma margin through which the sub‐ICM fluid seeps under the normal retina from the break. Based on intraoperative findings in this study, prophylactic laser to margins of coloboma sparing the vascular arcades may seal off this potential communication and prevent retinal detachment in such eyes.