Panretinal Photocoagulation Indications Beyond Diabetic Retinopathy
Panretinal photocoagulation is indicated for retinal ischemic conditions that cause neovascularization, most notably ischemic central retinal vein occlusion (CRVO), and can be considered for central retinal artery obstruction (CRAO) with rubeosis iridis, though the evidence base is substantially weaker than for diabetic retinopathy. 1, 2, 3
Primary Non-Diabetic Indications
Ischemic Central Retinal Vein Occlusion (CRVO)
PRP reduces iris neovascularization in ischemic CRVO when performed within 90 days of onset, though it does not significantly prevent angle neovascularization, neovascular glaucoma, or vitreous hemorrhage compared to observation 2
The timing is critical: PRP must be delivered before the development of elevated intraocular pressure to have any meaningful effect on preventing neovascular glaucoma 1, 2
Disseminated panretinal laser photocoagulation remains indicated for RVO patients with large areas of nonperfusion who have developed neovascularization and/or late complications 3
Targeted laser photocoagulation of peripheral areas of nonperfusion is emerging as a strategy to reduce the duration and number of anti-VEGF injections needed, though clear evidence is still pending from ongoing prospective randomized studies 3
Central Retinal Artery Obstruction (CRAO) with Rubeosis Iridis
PRP appears effective in reducing neovascular glaucoma incidence in CRAO when delivered before elevated IOP develops, with 65% of patients (11/17) showing regression of iris neovascularization after treatment 1
Once neovascular glaucoma has occurred, PRP alone is insufficient and additional modalities are necessary to control elevated IOP 1
The evidence for this indication is limited to retrospective, uncontrolled case series, making it a weaker recommendation than for diabetic retinopathy or CRVO 1
Important Clinical Distinctions
Why PRP Works Differently in Non-Diabetic Conditions
The response to PRP in ischemic CRVO differs substantially from proliferative diabetic retinopathy, likely due to differences in the underlying disease processes and the nature of retinal ischemia 2
Unlike diabetic retinopathy where PRP has proven benefit for retinal and disc neovascularization, PRP in ischemic CRVO primarily affects iris neovascularization only, and only when performed early 2
The 10-year prospective study of ischemic CRVO showed no statistically significant difference in retinal/optic disc neovascularization or vitreous hemorrhage between lasered and non-lasered eyes, highlighting the limited scope of benefit 2
Common Pitfalls and Caveats
Do not delay PRP in ischemic CRVO beyond 90 days if you intend to treat—the window for preventing iris neovascularization closes rapidly, and treatment after this period shows no benefit 2
Do not use PRP as monotherapy once neovascular glaucoma has developed—additional interventions including glaucoma surgery or tube shunts will be required 1
Expect significant peripheral visual field loss as a trade-off for PRP treatment in all ischemic retinal conditions, not just diabetic retinopathy 2, 4
Consider anti-VEGF therapy as first-line treatment for retinal vein occlusion with macular edema or neovascularization, reserving PRP for cases with persistent large areas of nonperfusion despite intravitreal injections 3
Avoid intensive single-session PRP with high power and long duration burns, as this increases risk of choroidal effusions, exudative retinal detachments, and macular edema 4