A proposed new classification for diabetic retinopathy: The concept of primary and secondary vitreopathy

BACKGROUND: Many eyes with proliferative diabetic retinopathy (PDR) require vitreous surgery despite complete regression of new vessels with pan retinal laser photocoagulation (PRP). Changes in the vitreous caused by diabetes mellitus and diabetic retinopathy may continue to progress independent of laser regressed status of retinopathy. Diabetic vitreopathy can be an independent manifestation of the disease process. AIM: To examine this concept by studying the long-term behavior of the vitreous in cases of PDR regressed with PRP. MATERIALS AND METHODS: Seventy-four eyes with pure PDR (without clinically evident vitreous traction) showing fundus fluorescein angiography (FFA) proven regression of new vessels following PRP were retrospectively studied out of a total of 1380 eyes photocoagulated between March 2001 and September 2006 for PDR of varying severity. Follow-up was available from one to four years. RESULTS: Twenty-three percent of eyes showing FFA-proven regression of new vessels with laser required to undergo surgery for indications produced by vitreous traction such as recurrent vitreous hemorrhage, tractional retinal detachment, secondary rhegmatogenous retinal detachment and tractional macular edema within one to four years. CONCLUSION: Vitreous changes continued to progress despite regression of PDR in many diabetics. We identifies this as “clinical diabetic vitreopathy” and propose an expanded classification for diabetic retinopathy to signify these changes and to redefine the indications for surgery.