Dear Editor,
We went through the article titled “Nasal vein occlusion after COVID-19: A case report” by Güven et al.[1] The authors have reported an interesting case of nasal retinal vein occlusion (RVO) in a patient diagnosed with coronavirus disease (COVID-19) 2 months back. The authors have mentioned that the patient presented to them with floaters. Most patients with nasal RVO are usually asymptomatic and unaware of the retinal condition because of the non-involvement of the macula. When the patients are symptomatic, it is mostly due to vitreous hemorrhage arising out of undetected retinal neovascularization. It will be interesting to know what the cause of the floaters was in this particular patient. Was there any hemorrhage in the vitreous or any vitreous degeneration which might have led to the floaters? The authors have also mentioned that following treatment with oral steroids and anticoagulants, the patient was relieved of symptoms of blurred vision within one week of institution of the therapy. We find this statement slightly controversial as the patient did not present with complaints of blurring of vision. His best corrected visual acuity in the affected eye was 20/20 and he only complained of floaters.
The authors have mentioned that the D-dimer levels were moderately elevated to 404 μg/L with a normal value being <243 μg/L. D-dimer levels tend to naturally increase with increasing age.[2] The D-dimer threshold for elderly patients above 50 years can safely be increased by multiplying their age in years by 10.[2] The patient also had elevated erythrocyte sedimentation rate and C-reactive protein. These can also be elevated in patients with connective tissue disorders. Minimal investigations in line with a connective tissue etiology are warranted in this case. Raised serum homocysteine levels are also independently associated with RVO.[3] Endothelial toxicity, promotion of smooth muscle proliferation, intimal thickening, increased platelet adhesion, activation of factor V, and decreased production of nitric oxide and prostacyclin are the most probable causes of thrombosis induced by raised serum homocysteine levels.[4]
There is a temporal association between COVID-19 and nasal RVO in this case. However, this association seems coincidental rather than being causal. Investigations to rule out other possible etiologies should be performed when the patient returns for follow-up examinations.
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References
- 1.Güven YZ, Akbalık T, Akay F. Nasal vein occlusion after COVID-19: A case report. Indian J Ophthalmol. 2022;70:2195–6. doi: 10.4103/ijo.IJO_680_22. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Linkins LA, Takach Lapner S. Review of D-dimer testing: Good, Bad, and Ugly. Int J Lab Hematol. 2017;39((Suppl 1)):98–103. doi: 10.1111/ijlh.12665. [DOI] [PubMed] [Google Scholar]
- 3.Panigrahi PK. Comment on: Central retinal vein occlusion post-COVID-19 vaccination. Indian J Ophthalmol. 2022;70:1863. doi: 10.4103/ijo.IJO_3155_21. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Panigrahi PK, Samant S, Dhar SK. A rare case of bilateral superior ophthalmic vein thrombosis presenting simultaneously with central retinal vein occlusion and cerebral venous sinus thrombosis. Indian J Ophthalmol Case Rep. 2022;2:229–31. [Google Scholar]