Doft BH, Wisniewski SR, Kelsey SF, Groer-Fitzgerald S. Diabetes and postoperative endophthalmitis vitrectomy study. Arch Ophthamol 2001;119: 650–656.
Original study reprint requests: Bernard H. Doft, EVS Coordinating Center, 3501 Forbes Avenue, Suite 500, Pittsburgh, PA 15213.
To determine whether there was a different response to vitrectomy and tap/biopsy with or without systemic antibiotic treatment in the Endophthalmitis Vitrectomy Study and whether the signs and symptoms of endophthalmitis differ between patients with or without diabetes.
A multicenter clinical trial study.
Multiple centers on behalf of the Endophthalmitis Study Group.
The National Eye Institute.
Patients with acute postcataract extraction endophthalmitis were randomly assigned in a 2 × 2 factorial design to vitrectomy or tap/biopsy, in each case with or without intravenous antibiotics, and followed up for 9 months.
Visual acuity assessed in standardized fashion.
Fifty-eight of 420 study patients had diabetes. Patients with diabetes had slightly worse vision and ocular media at the baseline assessment. Only 39% of patients with diabetes compared with 55% of patients without diabetes achieved 20/40 final vision. Both patients with diabetes and patients without diabetes with initial light perception (LP)-only vision had better visual results with immediate vitrectomy. For those with better than LP baseline vision, patients with diabetes achieved visual acuity of 20/40 more often with vitrectomy (57%) than with tap/biopsy (40%), but this difference was not statistically significant. Patients without diabetes did equally well with vitrectomy or tap/biopsy.
For patients with better than LP vision, tap/biopsy is appropriate for those without diabetes. A clinical trial of a sufficient number of patients with diabetes with better than LP vision is necessary to determine the best management for this group. At present, initial vitrectomy or tap/biopsy are reasonable approaches for patients with diabetes with better than LP vision.
The Endophthalmitis Vitrectomy Study (EVS) provided important data on the clinical diagnosis, microbiology, and treatment outcomes of patients with postcataract surgery or postsecondary IOL insertion endophthalmitis. Today the guidelines of the EVS are commonly used in the management of patients with this disease.
The current EVS report focuses on endophthalmitis in patients with diabetes who have generally worse visual acuity and ocular media opacities at the baseline assessment compared to the nondiabetic group. 1 There was no view of a retinal vessel in 89.7% of patients with diabetes compared to 77.4% for patients without diabetes (p = 0.09). Rubeosis iridis was present in 8.6% of eyes in the diabetic group compared with 1.9% of the nondiabetic eyes. In patients with a hypopyon, those with diabetes had a larger hypopyon (medium, 1.5 mm for patients with diabetes versus 1.0 mm for those without diabetes;p = 0.03). Gram positive, coagulase-negative micrococci were significantly more likely to grow from eyes of patients with diabetes (58.6%) than from eyes of patients without diabetes (45.0%). Additional procedures were performed in 20.7% of patients with diabetes versus 8.8% of patients without diabetes.
The outcomes of treatment confirm the poorer prognosis in patients with diabetes. Overall, only 39% percent of patients with diabetes compared with 55% of patients without diabetes achieved 20/40 or better final visual acuity. For those patients with better than LP baseline acuity, patients with diabetes achieved visual acuity of 20/40 or better more often with vitrectomy (57%) than with tap/biopsy (40%).
What can we take away from this EVS article? Although patients with diabetes with visual acuity better than LP were likely to achieve 20/40 or better more often after treatment with vitrectomy than with tap/biopsy, the difference was not statistically significant. Because of the trend toward better visual outcomes with vitrectomy, practitioners should feel comfortable using a three-port pars plana vitrectomy for the initial treatment of endophthalmitis in most patients with diabetes. However, keep in mind that the limited number of patients in the group of patients with diabetes in the EVS does not allow the power to reach a statistically significant conclusion. A larger number of patients with diabetes (360) with better than LP vision would be required to obtain a 90% power of detecting a statistically significant difference.
In previous EVS publications, a treatment group using the systemic antibiotics (amikacin and ceftazidime) did not achieve improved visual acuity or media clarity outcomes compared to a control group. Ironically, in the subgroup of patients with diabetes in the EVS, the use of systemic antibiotics appeared to have a deleterious effect on final visual acuity outcomes. Again, statistical confirmation of this observation would require a much larger sample size to adequately answer the role of systemic antibiotics in this diabetic subgroup.
Finally, the article discusses the relatively high percentage of patients with diabetes in larger series of postoperative endophthalmitis. 2,3 Because of the relative immune compromise in patients with diabetes and higher published rates of nonocular infection among patients with diabetes, this observation would be expected. In addition, the occurrence of endophthalmitis may aggravate preexisting diabetic retinopathy. 4 This worsened retinopathy may contribute to the poorer visual acuity outcomes in the EVS.
1. Doft BH, Wisniewski SR, Kelsey SF, et al. and the EVS Study Group. Diabetes and postoperative endophthalmitis in the endophthalmitis vitrectomy study. Arch Ophthalmol
2. Phillips II, WB Tasman WS. Postoperative endophthalmitis in association with diabetes mellitus. Ophthalmology 1994; 101:508–518.
3. Cohen SM, Flynn Jr, HW Murray TG, et al. and the Post Vitrectomy Endophthalmitis Study group. Endophthalmitis after pars plana vitrectomy. Ophthalmology
4. Dev S, Pulido JS, Tessler HH, et al. Progression of diabetic retinopathy after endophthalmitis. Ophthalmology 1999; 106:774–781.