Proliferative Diabetic Retinopathy

Quantitative analysis of DR lesions on UWF images identifies new risk parameters for progression to PDR including the surface area of hemorrhages and the distance of hemorrhages from the ONH. They highlight the potential for quantitative lesion analysis to inform the design of a more precise and complete staging system for diabetic retinopathy severity in the future.{Sadda SR, Nittala MG, Taweebanjongsin W, Verma A, Velaga SB, Alagorie AR, Sears CM, Silva PS, Aiello LP. Quantitative Assessment of the Severity of Diabetic Retinopathy. Am J Ophthalmol. 2020 Oct;218:342-352.}

Provided careful follow-up can be maintained, scatter photocoagulation is not recommended for eyes with mild or moderate nonproliferative diabetic retinopathy. When retinopathy is more severe, scatter photocoagulation should be considered and usually should not be delayed if the eye has reached the high-risk proliferative stage.{Early photocoagulation for diabetic retinopathy. ETDRS report number 9. Early Treatment Diabetic Retinopathy Study Research Group. Ophthalmology. 1991 May;98(5 Suppl):766-85. PMID: 2062512.}

Modern laser techniques and modalities have been developed to treat PDR. However there is limited evidence available with respect to the efficacy and safety of alternative laser systems or strategies compared with the standard argon laser as described in ETDRS.{Moutray T, Evans JR, Lois N, Armstrong DJ, Peto T, Azuara-Blanco A. Different lasers and techniques for proliferative diabetic retinopathy. Cochrane Database Syst Rev. 2018 Mar 15;3(3):CD012314.}

There is, as yet, no convincing evidence that modern laser systems are more effective than the argon laser used in ETDRS, but they appear to have fewer adverse effects.{Royle P, Mistry H, Auguste P, Shyangdan D, Freeman K, Lois N, Waugh N. Pan-retinal photocoagulation and other forms of laser treatment and drug therapies for non-proliferative diabetic retinopathy: systematic review and economic evaluation. Health Technol Assess. 2015 Jul;19(51):v-xxviii, 1-247.}

Ranibizumab treatment resulted in DR improvements in all 3 baseline DR severity subsets examined. The greatest benefits in DR improvement occurred in patients with baseline moderately severe to severe NPDR. Diabetic retinopathy improvements were rapid, clinically meaningful, and sustained through month 36.{Wykoff CC, Eichenbaum DA, Roth DB, Hill L, Fung AE, Haskova Z. Ranibizumab Induces Regression of Diabetic Retinopathy in Most Patients at High Risk of Progression to Proliferative Diabetic Retinopathy. Ophthalmol Retina. 2018 Oct;2(10):997-1009.}

Severe vision loss or serious complications of PDR were uncommon with Panretinal photocoagulation or ranibizumab, although the ranibizumab group had lower rates of developing diabetic macular edema and less visual field loss. Patient-specific factors such as compliance and cost should be considered in the choice of treatment.{Gross JG, Glassman AR, Liu D, Sun JK, Antoszyk AN, Baker CW, Bressler NM, Elman MJ, Ferris FL 3rd, Gardner TW, Jampol LM, Martin DF, Melia M, Stockdale CR, Beck RW; Diabetic Retinopathy Clinical Research Network. Five-Year Outcomes of Panretinal Photocoagulation vs Intravitreous Ranibizumab for Proliferative Diabetic Retinopathy: A Randomized Clinical Trial. JAMA Ophthalmol. 2018 Oct 1;136(10):1138-1148.}

Patients with proliferative diabetic retinopathy who were treated with intravitreal aflibercept had an improved visual outcome at 1 year compared to PRP.{Sivaprasad S, Prevost AT, Vasconcelos JC, Riddell A, Murphy C, Kelly J, Bainbridge J, Tudor-Edwards R, Hopkins D, Hykin P; CLARITY Study Group. Clinical efficacy of intravitreal aflibercept versus panretinal photocoagulation for best corrected visual acuity in patients with proliferative diabetic retinopathy at 52 weeks (CLARITY): a multicentre, single-blinded, randomised, controlled, phase 2b, non-inferiority trial. Lancet. 2017 Jun 3;389(10085):2193-2203.}