Abstract
Purpose :
Pre-operative dry eye represents a risk of sub-optimal refractive results following cataract or refractive surgery thus identification of at-risk individuals in the standard population is essential to optimising outcomes. Tear film osmolarity (TFO) is an objective measure of dry eye however minimal literature is available to provide an understanding of incidence of hyperosmolarity in the standard population and the relationship with subjective dry eye parameters and clinical variables. Our retrospective study presents a novel analysis of the largest current sample of TFO in a normal population and post-refractive subgroup.
Methods :
1404 patients (n=47 post-refractive, n=1357 standard) undergoing screening for refractive surgery from 2017 to 2020 were reviewed. Routine examination included dry eye testing with TFO (TearLab, San Diego, CA, USA) and the Ocular Surface Disease Index questionnaire (OSDI, Allergan Irvine CA, USA). Patients were instructed to refrain from topical eye drops minimum two hours before the appointment. Bivariate correlation was used to indicate a relationship between continuous variables and chi-square test between categorical variables. Mean, median and range values were provided for continuous variables.
Results :
Mean TFO in the standard population was 299.1±11.9mOsm/L with 82.3% of eyes <308mOsm/L indicating normal tear film homeostasis. Mean inter-eye TFO difference was 8.17±8.60mOsm/L with 65.2% of eyes <=8mOsm/L. Mean TFO in the post-refractive subgroup was 299.7±11.0mOsm/L with a mean inter-eye difference of 9.0±6.9mOsm/L. Post-refractive surgery patients indicated higher mean OSDI values of 15.3±14.5 compared to the remainder of the population 9.7±10.6 (p=0.012). Significant correlation was demonstrated between TFO scores and OSDI classification for the standard population only (p=0.005, r=0.077). Contact lens use correlated inversely with TFO and OSDI scores (p=0.000) whilst artificial lubricants correlated with OSDI scores in the post-refractive group only (p=0.000, r=0.131).
Conclusions :
TFO and OSDI scores indicate that the majority of the standard population fall within normal ranges. The impact of our findings may resonate with cataract and refractive surgeons as a reasonable percentage of individuals will be diagnosed with tear film hyperosmolarity and represent a risk for reduced post-operative outcome and ocular comfort.
This is a 2021 ARVO Annual Meeting abstract.