Abstract
Purpose :
Neuropathic corneal pain NCP is commonly thought to present with discordant signs and symptoms with minimal to no ocular surface staining. However, the Schirmer’s test result in patients with NCP have previously not been compared to patient with conventional dry eye disease DED. Thus, the purpose of the current study was to compare Schirmer’s test results between patients with NCP as compared to DED.
Methods :
This is a comparative, retrospective case-control study of age and sex matched NCP and DED patients, who were seen at the New England Eye Center between August 2018 and November 2020. NCP was diagnosed clinically and confirmed by in vivo confocal microscopy and the proparacaine challenge. Demographics, Schirmer’s test results with anesthesia, tear-break-up time TBUT, corneal staining CFS, ocular pain scores, ocular and systemic comorbidities were recorded. Patients were included in the DED group, based on the inclusion criteria of CFS staining≥4 and TBUT≤7.
Results :
The mean age of patients with NCP was 45.7±4.9 with n=4 males and n=19 females, and 63.1±3.9 for the DED group with n=5 males, and n=14 females p=0.199 for age p=0.707 for gender. The mean Schirmer’s tests results for the NCP group were 9.8mm±1.8 and 7.1mm±1.1 for the DED group, respectively with a p value of p=0.450. This indicated no significant difference in Schirmer’s results between the DED and NCP patients, with both groups demonstrating decreased results compared to healthy subjects. There was no difference in Schirmer’s results in the NCP group regardless of breakdown into peripheral n=3 mean 8.67±5.78, mixed n=9 mean 12.33±2.73 and central n=3 mean 5.00±1.16 p=0.383. The mean TBUT for the DED group was 4.0sec±0.4 and 10.2sec±0.5 for the NCP group p= <.001. The mean CFS was 4.1±1.0 for DED, and 0.4±0.2 for the NCP group p=.011. DED patients reported a mean pain level of 1.9±0.7on VAS, while NCP patients reported VAS of 4.5±0.3 p=.002. DED patients reported a mean of 1.8±0.7 on OPAS questions 5-7 indicating pain over the previous 24hr period, while NCP patients reported 5.0±0.7 p=.001.
Conclusions :
The results of this study shows that NCP patients may present with low values on Schirmer’s tests in the absence of clinical signs of DED. The data suggests that abnormal Schirmer’s test results may be due to nerve dysfunction and that abnormal Schirmer’s tests results should not be used to exclude NCP.
This is a 2021 ARVO Annual Meeting abstract.