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CHICAGO -- Diabetic patients without retinopathy achieved 20/20 vision after cataract surgery as often as nondiabetic patients did, a retrospective analysis of a large community-based cohort showed.

Patients without diabetes had a best corrected visual acuity (BCVA) of 20/25 following uncomplicated phacoemulsification compared with BCVA of 20/26 for patients with diabetes but no retinopathy. Patients with mild or moderate nonproliferative diabetic retinopathy (NPDR) had similar outcomes.

Only patients with severe NPDR or any degree of proliferative diabetic retinopathy (PDR) had worse vision outcomes as compared with nondiabetic patients. The average change in the logarithm of the Minimum Angle of Resolution (logMAR) after surgery did not differ significantly across all subgroups evaluated, including those with NPDR and PDR, Geraldine Slean, MD, of Kaiser Permanente in Oakland, California, reported at the American Academy Ophthalmology (AAO) meeting.

"Patients with diabetic retinopathy were less likely to achieve 20/20 postoperative best corrected visual acuity, as compared with non-DR patients, with a trend towards worsening of best corrected visual acuity with increasing severity of diabetic retinopathy," said Slean. "All patients -- including those with and without diabetes and those with and without DR -- gained four lines of vision with cataract surgery. Attaining 20/20 postoperative best corrected visual acuity was not associated with preoperative HbA1c."

"Cataract surgery should not be delayed solely on the basis of HbA1c levels. Timely cataract surgery can be of great benefit to these patients and should be considered irrespective of HbA1c levels," Slean added.

Multiple prior studies examined outcomes with cataract surgery in diabetic patients, said AAO program moderator Kevin Miller, MD, of the University of California Los Angeles. He asked what new information the Kaiser Permanente study added to the existing body of evidence.

"I think it's the HbA1c," she responded. "HbA1c is not making a huge impact on the postoperative visual acuity, and so it shouldn't be considered in our preoperative assessment."

Slean reported findings from a study to determine outcomes with cataract surgery in patients with type 2 diabetes. She and her colleagues also sought to determine the impact of retinopathy severity, duration of diabetes, and preoperative HbA1c on visual outcomes following phacoemulsification.

The retrospective cohort study included 65,370 patients who had at least 1 year of continuous enrollment in Kaiser Permanente Northern California during 2010-2015 and underwent noncomplex phacoemulsification. Investigators excluded patients with preoperative macular edema, patients with type 1 diabetes, and patients whose surgery was performed by a retina or oculoplastics specialist.

About a third of the patients (n=22,360) had type 2 diabetes: 18,176 without retinopathy, 1,751 with NPDR, 791 with moderate NPDR, 43 with severe NPDR, 1,097 with NPDR not otherwise specified, and 791 with PDR. Among patients for whom duration of diabetes could be ascertained, 8,196 had a disease duration <10 years and 9,196 had a longer duration of the disease.

Slean reported that 41% (n=9,214) of the diabetic patients had no diabetes-specific treatment at the time of surgery, 8,578 were treated with oral medications only, and 4,568 were on insulin with or without oral medication. A majority of the diabetic patients no had preoperative HbA1c measurement. Of the remaining patients with diabetes, 2,812 had preoperative HbA1c values <6.5%, 5,512 had values in the range of 6.5-8.9%, and 935 had HbA1c ≥9.0% in in 935.

Excluding patients with severe NPDR or PDR, preoperative BCVA averaged 0.53 logMAR in patients without diabetes, 0.55 for patients with diabetes and no retinopathy, and 0.57-0.59 for patients with no more than mild or moderate NPDR. Patients with severe NPDR had a preoperative logMAR of 0.68, and those with PDR had an average logMAR of 0.67. Snellen Equivalent BCVA averaged 20/68 for patients without diabetes, 20/71 for those with diabetes and no retinopathy, and 20/74 to 20/77 for patients with mild/moderate NPDR. Preoperative Snellen averages were 20/96 and 20/93 for patients with severe NPDR and PDR, respectively.

Following cataract procedures, the logMAR averaged 0.10 among nondiabetic patients, 0.11 in those with diabetes and no retinopathy, and 0.13-0.15 in patients with mild/moderate NPDR. Patients with severe NPDR and PDR had postoperative logMAR means of 0.18 and 0.23, respectively. BCVA by the Snellen method ranged from 20/25 to 20/28 for patients without diabetes, those with diabetes and no retinopathy, and those with mild/moderate NPDR. The means increased to 20/30 and 20/34 for patients with severe NPDR and PDR.

The average change in logMAR after surgery ranged from -0.43 to -0.45 for all groups except the patients with severe NPDR, who had a mean change of -0.50. Between-group differences did not achieve statistical significance.

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