Abstract
Purpose: :
To compare visual acuity (VA) and diabetic retinopathy (DR) outcomes over a 4 yr period after pars plana vitrectomy (PPV) versus combined PPV, phacoemulsification and intraocular lens implantation (PPVCE) in patients with diabetes mellitus (DM).
Methods: :
Retrospective chart review of all DM patients undergoing PPV or PPVCE between 4/1/2001-12/31/2006 at the Joslin Diabetes Center. PPV was performed by a single retinal surgeon. CE was performed by 1 of 3 surgeons prior to PPV. ETDRS protocol VA, DR severity, and postop complication data were recorded on standardized forms for pre- & postoperative visits up to 4 yrs.
Results: :
251 eyes of 222 patients were evaluated (PPV:122, PPVCE:129). Follow-up at 4 yrs occurred for 161 eyes (64%). Median age was 64 y (Q1,Q3: 55,70), DM duration 27 y (18, 35), HbA1c 7.8% (6.9, 8.9); 48% male, and 45% Type 1 DM. The PPVCE group had better preop VA (20/80 vs 20/160, p=0.03), less baseline PDR (66% vs 89%, p<0.0001), older patients (64 vs 60 yrs, p=0.0005), more hyperlipidemia (85% vs 71%, p =0.009) and more HTN (91% vs 81%, p=0.03). Postop VA improved in both groups but PPV eyes improved more at years 2, 3, & 4 [median letter improvement (15 vs 10), (20 vs 10), (22 vs 11), p =0.02, 0.04, 0.05 respectively]; however these differences were not significant after adjusting for preop VA. At 4 yrs, PPV group VA was not better [(20/32 vs 20/50 (p=0.08)] and there was no difference in DR progression between the groups. At years 2, 3, & 4, more PPVCE eyes developed neovascular glaucoma (NVG) [(8.6% vs 1.2%), (11.8% vs 1.2%), (8.2% vs 2.3%), p= 0.03, 0.01, 0.05, respectively] and this was significant even after correcting for baseline DR, age, hyperlipidemia and hypertension. At 4 yrs (adjusted for preop VA), VA was worse in eyes with NVG in the combined cohort (20/60 vs 20/40, p=0.01, 11 NVG eyes) and in the PPVCE group (20/1000 vs 20/50, p<0.001, 9 NVG eyes). There was no difference between the groups in the incidence of other postop complications (eg vitreous hemorrhage & traction retinal detachment).
Conclusions: :
Substantial visual improvement occurs over the 4 yrs following either PPV or PPVCE in patients with DM. Although PPVCE visual outcomes were not significantly worse than those after PPV alone, over this period there was a higher rate of NVG and associated VA loss.