|Year : 2022 | Volume
| Issue : 2 | Page : 447-448
Commentary: Unilateral proliferative diabetic retinopathy following central retinal vein occlusion
Ashish Markan1, Mohit Dogra1, Manasi Tripathi2
1 Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
2 Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||13-Apr-2022|
Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Markan A, Dogra M, Tripathi M. Commentary: Unilateral proliferative diabetic retinopathy following central retinal vein occlusion. Indian J Ophthalmol Case Rep 2022;2:447-8
|How to cite this URL:|
Markan A, Dogra M, Tripathi M. Commentary: Unilateral proliferative diabetic retinopathy following central retinal vein occlusion. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2022 May 18];2:447-8. Available from: https://www.ijoreports.in/text.asp?2022/2/2/447/342969
Diabetic retinopathy (DR) is one of the most common microangiopathies associated with diabetes mellitus. It is a symmetric disease that develops over a long period of time. Asymmetric diabetic retinopathy (ADR) is a rare form of DR and is seen in 5%–10% of proliferative DR (PDR). ADR is defined as PDR in one eye and nonproliferative DR/preproliferative DR or no DR in the other eye over a period of a minimum of 2 years., It is important to detect ADR and investigate it thoroughly as it is associated with severe vision loss. Various ocular and systemic conditions have been implicated in the development of ADR. Factors associated with the increased progression of DR and factors that are protective for the development of DR have been listed below [Table 1]. A brief overview of the proposed mechanism associated with these factors is also discussed briefly.
Risk factors for progression of DR
Studies have shown branch retinal vein occlusion to significantly increase the risk of PDR and is thus associated with ADR. Long-standing BRVO is associated with significant ischemia and development of neovascularization, thus accelerating the process of proliferation in DR.
Similarly, carotid artery disease (CAD) is associated with an increased risk of neovascularization. Dogru et al. showed the presence of >90% stenosis in carotid artery ipsilateral to PDR in patients with asymmetric retinopathy. It is believed that carotid stenosis has an additive effect on both ocular ischemic syndrome and diabetes, thus accounting for an increased risk of neovascularization. Similarly, slow flow in the ophthalmic artery can cause nonischemic central vein occlusion and subsequent development of PDR in the same eye. Ocular ischemic syndrome primarily causes peripheral retinopathy, but with the presence of DR, the effect of both ocular conditions is difficult to differentiate. ADR may be a sign of increased vascular mortality and risk of ischemic heart disease, stroke, cerebral vascular accident, peripheral vascular disease, and sudden death. Presence of ADR warrants a thorough systemic evaluation to rule out the presence of associated CAD.
Some other proposed risk factors for proliferative retinopathy are unilateral aphakia, previous extracapsular or intracapsular cataract extraction, and vitreous loss., Similarly, trauma, tumor, radiation, and uveitis have also been implicated as risk factors for increased progression of DR. The mechanism associated with these risk factors is still unknown.
Protective factors against progression of DR
Chorioretinal scarring exerts a protective effect on the development of neovascularization and is associated with less severe retinopathy in the affected eye. The proposed mechanism includes an associated loss of retinal ganglion cells and optic atrophy, which decreases the metabolic requirement of the retinal cells. This reduced oxygenation demand decreases the ischemic stimulus for neovascularization.
Similarly, the presence of a complete posterior vitreous detachment (PVD) is associated with a decreased risk of retinopathy, whereas no PVD or partial PVD and vitreous traction is a grave prognostic sign indicating a higher risk of progression for PDR. It is believed that a component of vitreoretinal attachment might provide a scaffold for the growth of neovascularization and thus promote proliferative retinopathy.
Other proposed factors associated with a decreased metabolic demand and a decreased risk of PDR include optic atrophy, retinal pigment epithelial atrophy, and high myopia (amblyopia). A recent study by Kim et al. has shown the protective effect of axial length on the progression of DR. Eyes with a shorter axial length had a significantly higher risk of PDR as compared to long eyes.
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