BackgroundVitrectomy may not only remove vitreous hemorrhage but also prevent or relieve traction on the retina from contraction of the fibrovascular membranes that characterize severe proliferative diabetic retinopathy. It is important to determine whether early intervention with vitrectomy has a better visual outcome or instead produces a rate of serious complications higher than the rate associated with conventional management.
DescriptionTwo randomized trials were carried out in the DRVS among patients ages 18 to 70 years who had either insulin-dependent or non-insulin-dependent diabetes. In the first trial, the 616 patients who were recruited had severe visual loss from recent severe vitreous hemorrhage in at least one eye. Eligible eyes were randomly assigned either to early vitrectomy or to conventional management. In the conventional management group, vitrectomy was carried out 1 year later if hemorrhage persisted; vitrectomy was carried out sooner if retinal detachment -involving the center of the macula occurred.
In the second
trial, 381 patients were recruited, all of whom had severe fibrovascular
proliferations and useful vision in at least one eye. Eligible eyes were
assigned either to early vitrectomy or to conventional management. Conventional
management included photocoagulation when indicated, with vitrectomy if
a severe vitreous hemorrhage occurred and failed to clear spontaneously
during a 6-month waiting period or if retinal detachment involving the
center of the macula -occurred. After randomization and treatment, all
patients were examined at 6-month intervals for 2 years and annually thereafter.
Comparisons of visual acuity distributions between experimental and control
groups were made.
Patient EligibilityMen and women eligible for the vitreous hemorrhage group had at least one eye with recent severe vitreous hemorrhage (within 5 months) and visual acuity of 5/200 or less. Patients eligible for the "very severe proliferative retinopathy with useful vision" group had extensive active fibrovascular proliferations and visual acuity of 10/200 or better.
ResultsIn the severe vitreous hemorrhage trial, 2-year results showed that recovery of good vision (10/20 or better) was more frequent in the early vitrectomy group (25 percent versus 15 percent in the conventional management group). But there was also a trend toward more frequent loss of light perception in the early group (25 percent versus 19 percent). In the patients with insulin-dependent diabetes, who were younger and had more severe fibrovascular proliferations, the advantage of early vitrectomy was greater (36 percent with visual acuity of 10/20 or better in the early vitrectomy group versus 12 percent with conventional management) and the proportion losing light perception in the two groups was about equal (28 percent and 26 percent, respectively).
After 4 years of followup, conclusions remained largely the same. First for eyes with recent severe vitreous hemorrhage, early vitrectomy provided a greater chance of prompt recovery of visual acuity. Prompt recovery is of greatest importance in patients who do not have useful vision in the fellow eye, and offering early vitrectomy to such patients with little regard to retinopathy severity or diabetes type seems reasonable, although greater early risk of visual acuity of no light perception must be kept in mind. Second, for patients with insulin-dependent diabetes, particularly for those in whom severe vitreous hemorrhage occurred after a shorter duration of diabetes, early vitrectomy provided a greater chance of recovering good visual acuity. This benefit remained at least as great after 4 years of followup as it was at 2 years.
The DRVS findings
support early vitrectomy in eyes known or suspected to have very severe
proliferative diabetic retinopathy as a means of increasing the chance
of restoring or maintaining good vision.