This activity for Diabetic Retinopathy education is provided by Med Learning Group.
This activity is supported by an independent medical education grant from Regeneron Pharmaceuticals, Inc.
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Current and Emerging Management of PDR
Ideally, the best way to preserve vision is to keep diabetic retinopathy (DR) from developing. DR prevention plays a vital role in thwarting vision loss, as are early detection and treatment.1 However, while medical management and normalization of blood glucose levels are good habits to encourage, people with proliferative diabetic retinopathy (PDR) often require more urgent ocular intervention, including lasers and injections, to prevent significant visual consequences.1
Anti-vascular Endothelial Growth Factor (Anti-VEGF)
Studies show that anti-VEGF injections can be just as effective as panretinal photocoagulation (PRP) laser therapy, the classic treatment for PDR.1 In fact, people who receive these injections have better average visual acuity, less visual field loss, fewer vitrectomies, and fewer new developments of vision loss due to diabetic macular edema (DME).1
Macular edema, another facet of retinopathy, can appear at any stage of DR but is more common in more severe stages.1 DME, particularly center-involved (CI-) DME, can be vision-threatening for patients, necessitating ocular therapy.1 Focal macular laser used to be the mainstay of CI-DME treatment; however, intravitreal anti-VEGF injections have now become first-line therapy for DME.2
Two anti-VEGF agents, ranibizumab and aflibercept, are FDA-approved to treat PDR, or DR of any severity, with or without DME, supported by data from the Protocol S, RISE/RIDE, VIVID/VISTA, and PANORAMA trials.4 Off-label use of bevacizumab is sometimes employed by ophthalmologists as DR therapy.5 Additionally, faricimab was recently FDA-approved to treat DME.5 Higher molar concentration aflibercept (8mg) also received recent FDA-approval for the treatment of DR and DME (PHOTON).6 Many patients respond well to anti-VEGF agents, improving 1-3 lines or more on the Snellen vision chart.5 Because of the need for repeat injections to treat both PDR and DME, anti-VEGF agents are best utilized in patients with reliable follow-up and compliance.1
Laser Panretinal Photocoagulation (PRP)
High-risk PDR, characterized by severe NPDR with neovascularization and vitreous hemorrhage, carries an elevated risk of severe vision loss; PRP treatments can reduce this risk.1 When utilized, a full PRP treatment is preferred to a partial or limited approach.1
The overall goal of PRP is to reduce the risk of vision loss and early intervention may carry a better outcome.1 Studies show that early PRP may be beneficial for eyes with very severe nonproliferative diabetic retinopathy (NPDR) and high-risk factors, such as poor compliance with follow-up, impending cataract extraction or pregnancy, and blind or advanced DR in the fellow eye.1,8 Very severe NPDR has almost a 50% likelihood of worsening to PDR within 1 year; therefore, considerations should be made to treat people with PRP before the onset of high-risk PDR.1
Care should be taken in treating eyes with DME in addition to PDR, as PRP has been shown to worsen DME in some people.1 In cases where this may occur, eyes with DME can be treated with focal laser or anti-VEGF injections, either prior to PRP treatment or combined in the same session.1
Alternative Treatments
Some people with PDR may benefit from a vitrectomy surgery to help improve their vision, especially if they have already undergone treatment with anti-VEGF or PRP.1 Situations where vitrectomy may be used include:1
- Non-clearing vitreous hemorrhage
- Tractional retinal detachment threatening the macula
- Combined rhegmatogenous and tractional retinal detachment
- Dense pre-macular subhyaloid hemorrhage
Ideally, a vitrectomy is performed within the first 6 months after the onset of vitreous hemorrhage and should be followed regularly with serial ultrasounds.1 Persistent DME may also require additional treatment. If the DME does not respond after 3-6 monthly intravitreal injections, laser therapy or ocular steroids (either implants or injections) may help improve retinal thickening and visual acuity.2,5
References
- Flaxel CJ, Adelman RA, Bailey ST, et al. Diabetic Retinopathy Preferred Practice Pattern®. Ophthalmology. 2020;127:P66-P145.
- Figueira J, Henriques J, Carneiro Â, et al. Guidelines for the Management of Center-Involving Diabetic Macular Edema: Treatment Options and Patient Monitorization. Clin Ophthalmol. 2021;15:3221-3230.
- Yorston D. Intravitreal injection technique. Commmunity Eye Health. 2014;27:47.
- Yonekawa Y, Modi YS, Kim LA, et al. American Society of Retina Specialists Clinical Practice Guidelines: Management of Nonproliferative and Proliferative Diabetic Retinopathy Without Diabetic Macular Edema. J Vitreoret Dis. 2020;4:125-135.
- Jacoba CM, Mitzner MG, Vavallerano J, et al. Diabetic Macular Edema. American Academy of Ophthalmology®. EyeWiki® https://eyewiki.org/Diabetic_Macular_Edema
- News release. 8/18/23 (https://investor.regeneron.com/news-releases/news-release-details/eylea-hd-aflibercept-injection-8-mg-approved-fda-treatment-wet). Accessed August 30, 2023.
- American Academy of Ophthalmology® (AAO). Fundus photo showing scatter laser surgery for diabetic retinopathy. EyeWiki. https://eyewiki.aao.org/File:Fundus_photo_showing_scatter_laser_surgery_for_diabetic_retinopathy_EDA09.JPG
- Wong TY, Sun J, Kawasaki R, et al. Guidelines on Diabetic Eye Care: The International Council of Ophthalmology Recommendations for Screening, Follow-up, Referral, and Treatment Based on Resource Settings. Ophthalmology. 2018;125:1608-1622.
- Spirn MJ. Pars Plana Vitrectomy. American Academy of Ophthalmology®. EyeWiki. 2021. https://eyewiki.org/Pars_Plana_Vitrectomy
All URLs accessed 5/9/22.
