Visual Field Changes Over 5 Years in Patients Treated With Panretinal Photocoagulation or Ranibizumab for Proliferative Diabetic Retinopathy

Abstract

Importance: Preservation of peripheral visual field (VF) is considered an advantage for anti-vascular endothelial growth factor agents compared with panretinal photocoagulation (PRP) for treatment of proliferative diabetic retinopathy. Long-term data on VF are important when considering either treatment approach.

Objective: To further evaluate changes in VF throughout 5 years among eyes enrolled in the Protocol S clinical trial, conducted by the DRCR Retina Network.

Design, setting, and participants: Post hoc analyses of an ancillary study within a multicenter (55 US sites) randomized clinical trial. Individuals with eyes with proliferative diabetic retinopathy enrolled in Protocol S were included. Data were collected from February 2012 to February 2018. Analysis began in June 2018.

Interventions: Panretinal photocoagulation or intravitreous injections of 0.5-mg ranibizumab. Diabetic macular edema, whenever present, was treated with ranibizumab in both groups. Panretinal photocoagulation could be administered to eyes in the ranibizumab group when failure or futility criteria were met.

Main outcomes and measures: Mean change in total point score on VF testing with the Humphrey Field Analyzer 30-2 and 60-4 test patterns.

Results: Of 394 eyes enrolled in Protocol S, 234 (59.4%) were targeted for this ancillary study. Of these, 167 (71.4%) had VF meeting acceptable quality criteria at baseline (median [interquartile range] age, 50 [43-58] years; 90 men [53.9%]). At 5 years, 79 (33.8%) had results available. The mean (SD) change in total point score in the PRP and ranibizumab groups was -305 (521) dB and -36 (486) dB at 1 year, respectively, increasing to -527 (635) dB and -330 (645) dB at 5 years, respectively (P = .04). After censoring VF results after PRP treatments in the ranibizumab group, the 5-year mean change in total point score was -201 (442) dB. In a longitudinal regression analysis of change in total point score including both treatment groups, laser treatment was associated with a mean point decrease of 208 (95% CI, 112-304) dB for the initial PRP session, 77 (95% CI, 21-132) dB for additional PRP sessions, and 325 (95% CI, 211-439) dB for endolaser. No association was found between change in point score and the number of ranibizumab injections during the previous year (-9 per injection [95% CI, -22 to 3]).

Conclusions and relevance: The limited data available from Protocol S suggest that there are factors besides PRP associated with VF loss in eyes treated for proliferative diabetic retinopathy. Further clinical research is warranted to clarify the finding.

Trial registration: ClinicalTrials.gov identifier: NCT01489189.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Maguire, Mss Liu and Stockdale, and Mr Glassman report grants from the National Institutes of Health and nonfinancial and other support (ranibizumab and funds to defray clinical site costs) from Genentech during the conduct of the study and nonfinancial and other support from Regeneron and Allergan outside the submitted work. Dr Jampol reports grants from the National Eye Institute during the conduct of the study. Dr Baker reports grants from Regeneron, Roche, Novartis, and Allergan outside the submitted work. Dr Bressler reports grants from Bayer, Genentech/Roche, Novartis, and Samsung Bioepis outside the submitted work. Dr Gardner reports grants from Zebra Biologics outside the submitted work. Dr Pieramici reports grants and personal fees from Regeneron, Genentech, Novartis, Regenxbio, and Adverum Biotechnologies outside the submitted work. Dr Sun reports grants from Jaeb Center during the conduct of the study; nonfinancial support (equipment loaned for research) from Optovue, Boston Micromachines, and Adaptive Sensory Technology; grants and nonfinancial support from Roche, KalVista Pharmaceuticals, and Boehringer Ingelheim; grants from JDRF; personal fees from Current Diabetes Reports and JAMA Ophthalmology; personal fees and nonfinancial support from Merck and Novartis; and nonfinancial support from Novo Nordisk outside the submitted work. No other disclosures were reported.

Figures

Figure 1.. Flowchart of Eyes Included in the Ancillary Study on Visual Fields of Participants Enrolled in the Protocol S Clinical Trial

aDefined as eyes with at least 1 test pattern (either Humphrey Field Analyzer [HFA] 30-2 or HFA 60-4) available at baseline. bDefined as eyes with both test patterns (HFA 30-2 and HFA 60-4) available and excluding eyes that had excessive false positive or excessive fixation loss at baseline or other irregularities invalidating the results. For HFA 30-2 test, 28 and 32 scans were excluded from ranibizumab and panretinal photocoagulation groups, respectively; for HFA 60-4 test, 30 and 31 scans were excluded, respectively.

Figure 2.. Mean Change From Baseline in the Combined Total Score From the 30-2 and 60-4 Test Pattern

Outlying values were truncated to 3 SDs from the mean. Error bars represent 95% confidence intervals. The orange line indicates the mean change from baseline over time censoring ranibizumab eyes after the initiation of panretinal photocoagulation (PRP) treatment. NA indicates not applicable.