Table 2. Outpatient visits to Aravind Eye Care System facilities before and during the COVID-19 pandemic waves, Pondicherry and Tamil Nadu, India, 2019–2021.

Study perioda	No. outpatient visits							Study period visits as a proportion of comparison period visits (significance of difference between the periods)
	Study period in 2020 and 2021			Comparison period in 2019b,c				% (P value)d
	Tertiary care hospitals	Secondary care hospitals	Vision centrese	Tertiary care hospitals	Secondary care hospitals	Vision centrese		Tertiary care hospitals	Secondary care hospitals	Vision centrese
Pre-COVID-19	572 376	101 501	159 122	553 475	96 949	147 261		103 (< 0.0001)	105 (0.54)	108 (< 0.0001)
First wave of the COVID-19 pandemic	647 968	170 934	180 502	1 656 296	283 176	246 282		39 (< 0.0001)	60 (< 0.0001)	73 (< 0.0001)
After the first wave	1 037 133	187 089	247 006	1 046 539	180 841	272 754		99 (< 0.0001)	103 (< 0.0001)	91 (< 0.0001)
Second wave of the pandemic	385 092	88 383	121 993	710 949	121 739	154 007		54 (< 0.0001)	73 (< 0.0001)	79 (< 0.0001)
Total	2 642 569	547 907	708 623	3 967 259	682 705	820 304		67 (NA)	80 (NA)	86 (NA)

COVID-19: coronavirus disease 2019; NA: not applicable.

^a The pre-COVID-19 period was from 1 January 2020 to 23 March 2020; the first wave of the COVID-19 pandemic was from 24 March 2020 to 31 October 2020; the period after the first wave was from 1 November 2020 to 31 March 2021; and the second wave of the pandemic was from 1 April 2021 to 30 June 2021 (Table 1).

^b For the comparison period, dates in the study period were matched with dates in 2019, the last year before the pandemic (Table 1).

^c The 1 674 364 outpatient visits made between January and June 2019 were used twice for comparisons. Consequently, this figure was deducted when the total number of unique outpatient visits was calculated.

^d P values were derived using the two-sample proportion test.

^e Vision centres are primary care centres.