Clinical Studies:

DRS Report #14

Indications for Photocoagulation Treatment of Diabetic Retinopathy

Summarized by Matthew R. Starr, MD (Wills Eye Hospital, Mayo Clinic)

Citation: Indications for photocoagulation treatment of diabetic retinopathy: Diabetic Retinopathy Study Report no. 14. The Diabetic Retinopathy Study Research Group. Int Ophthalmol Clin. 1987;27(4):239-253. doi:10.1097/00004397-198702740-00004

  • Objective

    To determine the risks and benefits of photocoagulation versus observation for severe NPDR and PDR. Primary outcome was percent of eyes with severe vision loss (SVL, VA<5/200) at two or more consecutive 4 month follow up visits.


    Randomized, controlled, prospective clinical trial.

  • Duration

    24 months and 48 months



Both eyes of patients were randomized to either:

(a) laser photocoagulation (argon or xenon) completed in 1 or 2 sessions. Argon was 800-1600 burns, 500 microns in size, 0.1 second duration with direct treatment of NVD and NVE. Xenon technique was similar, but burns were smaller, longer duration and only direct treatment of NVE

(b) observation

The initial minimum follow up was planned for 5 years, however after an average of 15 months of follow up, there was a 60% reduction in blindness in the laser cohort and thus the protocol was changed. Initially untreated eyes that developed high risk characteristics (HRCs, moderate or severe NVD, NVD with VH or pre-retinal heme, or NVE ½ DD in size with VH and pre-retinal heme) were now considered for photocoagulation, The protocol was changed again and allowed eyes to be treated if the DRS investigator considered to be in the patient’s best interest.

RESULTS (before protocol change)

Rate of SVL

RESULTS (after protocol change – by 4 years, 35% of the original controls had been treated and eyes were resulted based on the original randomization cohort regardless of future treatment)

Rate of SVL

Other risk factors for SVL


Adverse events