Corona virus disease became a pandemic in early 2020.  The disease spread rapidly through droplet transmission.  Nationwide lockdown was imposed in various countries across the globe including India to control the pandemic. Healthcare facilities were asked to attend only emergency situations.  Ophthalmologists are among the most vulnerable subspecialties as social distancing is difficult during eye examinations.  A survey done by Nair AG et al mentioned that 72.5 % of ophthalmologists in India stopped seeing patients completely whereas 27.5 % ophthalmologists attended only emergency patients. Although comprehensive ophthalmic services are often elective and non-urgent, VR is an important sub specialty which deals with a lot of vision threatening conditions.
In view of the pandemic and in accordance with national guidelines, we, at our VR department of a tertiary eye care centre in southern India, discouraged consultations of non-urgent VR patients. The absolute number of VR patients who visited our department decreased drastically during the lockdown period. Though our services were open for all emergency VR patients, many of them could not access our services, probably due to non-availability of public transport and compromised livelihood. In this study we wish to understand the influence of the COVID-19 nation-wide lockdown on VRI at our tertiary VR centre in South India.
During lockdown, there was a 50% reduction in the proportion of female patients who underwent VRI. This could probably suggest the indirect greater influence of lockdown on the female gender. A similar gender pattern was observed by Das et al. [11, 12] Despite inter-district transport restrictions and non-availability of basic public transport facilities, we did not observe any major alteration in the proportion of VR patients who came from metro city and neighbouring districts. This suggests the awareness among patients regarding retinal disorders even in the smaller districts.
The fact that the absolute numbers decreased significantly for semi-urgent and less urgent VRI (combined reduction by 85 %) as compared to urgent VRI (reduction by 52 %) implies that there is good awareness among the general public and at the same time, commutation becomes a major barrier in health care access, especially, in the event of natural calamities.
Though there was no significant overall change in the proportion of surgical and medical VRI during lockdown, we observed that the MC indication for VR surgery during lockdown was RD whereas diabetic vitrectomy was the MC indication before lockdown. Das et al mentioned that RD (47.83 %) followed by endophthalmitis are the MC indications at their centre.  A retrospective study done by Agarwal D et al. showed that acute RD (38.5%) was the MC indication for emergency surgery during lockdown at their centre.  Tang et al. mentioned that RD surgery (47.4%) followed by open globe repair (15.8%) were the MC indication for emergency surgeries during lockdown at their tertiary eye care centre in Hong Kong. 
We analysed the top five retinal conditions needing some form of VRI during the lockdown and compared with pre- and post-lockdown periods. PDR, DME and CNVM are the top three retinal conditions which needed VRI throughout, irrespective of the lockdown status. Interestingly, CRVO became the 5th most common condition needing VRI in the immediate post lockdown status. There have been a few anecdotal reports correlating the occurrence of CRVO post COVID status in view of COVID-19 induced hypercoagulable status. Sheth JU et al reported a case of unilateral vasculitic retinal vein occlusion secondary to COVID after investigating and ruling out other causes of vasculitis.  A case of bilateral retinal vein occlusion was reported by Gaba WH et al in a 40-year-old male with active COVID signs, recovery to near normal vision with anticoagulant treatment.  However, we did not observe any major surge in the incidence of CRVO in the immediate post lockdown period as the absolute numbers remain more or less the same (18 CRVO patients in pre-lockdown and 16 in post lockdown period). It probably requires larger studies with longer follow up to ascertain any strong relationship between CRVO and COVID. The limitation in our study was that many of our patients were not tested for COVID, due to the prevailing difficulty in accessing COVID testing centres at that time. We noticed a significant fall in median pBCVA of VR patients who underwent VRI during the lockdown period, which again suggests that daily livelihood, public transport and awareness are key determinants of health care access. We observed a significant uptrend in the proportion of VR interventions when compared to cumulative non-retina interventions at our centre during the lockdown. This study thus also underscores the crucial role of retina sub specialty services in any comprehensive eye care facility.