Purpose: This study aimed to evaluate the ocular surface parameters of post-COVID-19 patients when compared to healthy controls.
Methods: Patients after symptomatic SARS-CoV-2 infection, as confirmed by a PCR test of their nasopharyngeal swab sample, were enrolled. Complete ophthalmic examination, including visual acuity test, intraocular pressure measurement (IOP), slit-lamp examination, tear osmolarity test, central corneal thickness, endothelial cell number measurements, non-invasive keratograph break-up time (NIKBUT), meniscus height, and the Schirmer's test were performed and compared with the controls.
Results: It must be noted that there were 36 COVID-19 patients and 25 control subjects included in the study. Eye itching and burning (19%) were the most common symptoms of COVID-19 infection, followed by a subjective decrease in vision (17%), conjunctivitis and eye pain were present in 11%, and 6% of the patients had episcleritis. The mean time from initial infection was 6.5 ± 3.9 (range 1-24 weeks). Meniscus height was not significantly changed between the COVID-19 (0.34 ± 0.13 mm) group and the control (0.33 ± 0.12 mm, p = 0.88) group. In addition, the NIKBUT-1 (p = 0.88; 7.22 ± 4.60 s and 6.91 ± 4.45 s) and NIKBUT average (p = 0.91, 12.30 ± 5.86 s and 11.77 ± 4.97 s) test results showed no significant change either. Neither was a significant result found in the IOP (p = 0.17, 14.56 ± 2.10 mmHg and 14.11 ± 1.96 mmHg); the Schirmer test (p = 0.18, 20.22 ± 7.92 mm and 20.02 ± 7.17 mm); Tosm (p = 0.16, 294.42 ± 54.51 mOsm/dL and 299.33 ± 5.65 mOsm/dL); CCT (p = 0.06, 549.15 ± 28.98 vs. 539.21 vs. 29.08 µm); nor the endothelial cell density (p = 0.07, 2516.64 ± 287.61 vs. 2454.21 ± 498.60 cells/mm2).
Conclusions: Through this study it was not revealed that there were any significant differences between the post-COVID group and control group in the objective measurements of ocular surface conditions, when performed after the acute phase of COVID-19. The exact incidence and mechanism of ocular findings, especially dry eye disease, in correlation with SARS-CoV-2 requires further research.
Keywords: COVID; conjunctivitis; dry eye disease; ocular surface; tear film.