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 Table of Contents  
Year : 2022  |  Volume : 2  |  Issue : 2  |  Page : 447-448

Commentary: Unilateral proliferative diabetic retinopathy following central retinal vein occlusion

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 Publication13-Apr-2022

Correspondence Address:
Ashish Markan
Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_2590_21

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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 Aug 17];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.[1],[2] 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.
Table 1: Factors affecting progression of PDR

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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.[1] 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.[3] 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.[4] 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.[5] 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.[1],[6] 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.[1] 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.[3] 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).[3] A recent study by Kim et al.[7] 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.

  References Top

Browning DJ, Flynn HW, Blankenship GW. Asymmetric retinopathy in patients with diabetes mellitus. Am J Ophthalmol 1988;105:584-9.  Back to cited text no. 1
Duker JS, Brown GC, Bosley TM, Colt CA, Reber R. Asymmetric proliferative diabetic retinopathy and carotid artery disease. Ophthalmology 1990;97:869-74.  Back to cited text no. 2
Dogru M, Inoue M, Nakamura M, Yamamoto M. Modifying factors related to asymmetric diabetic retinopathy. Eye (Lond) 1998;12:929-33.  Back to cited text no. 3
Mohan S, Bhende M. Unilateral proliferative diabetic retinopathy following central retinal vein occlusion. Indian J Ophthalmol Case Rep 2022;2:445-7.  Back to cited text no. 4
  [Full text]  
Turgut B. Asymmetrical diabetic retinopathy may be a significant sign of the mortal vascular disorder. J Eye Vis 2018;1.  Back to cited text no. 5
Valone JA, McMeel JW, Franks EP. Unilateral proliferative diabetic retinopathy. I. Initial findings. Arch Ophthalmol 1981;99:1357-61.  Back to cited text no. 6
Kim DY, Song JH, Kim YJ, Lee JY, Kim J-G, Yoon YH, et al. Asymmetric diabetic retinopathy progression in patients with axial anisometropia. Retina 2018;38:1809-15.  Back to cited text no. 7


  [Table 1]


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