Purpose
To profile dry eye signs, symptoms and function tests, and to study the relationship of these within subjects.
Methods
A detailed functional profile was carried out in 11 dry eye subjects. Within-subject correlations were calculated between: demographics, symptoms, quality of life (QoL), break up time (TFBUT), Schirmer’s tests (ST), tear turnover rate (TTR), tear volume (TV), fluorescein staining, corneal sensitivity (CS), lid redness, total/healthy meibomian gland (MG) number, secretion color (SC) and viscosity (SV) for each gland (upper +lower lids). Given the individual gland assessments, over 1000 outcomes were collected for each subject.
Results
Age and symptoms were inversely correlated (R2=-0.746, p=0.008), also when adjusted for disease duration, (discomfort: p=0.047; QoL, p = 0.017-0.048). Symptoms correlated with each other and QoL. Evening reading was most related to symptoms. Staining correlated well in all regions but superior cornea. TFBUT and CS were highly correlated (R2=0.89, p=0.0002). Conjunctival staining most related to symptoms (R2=0.712, p=0.014). Evening driving correlated highly with ST (R2=-0.7721, p=0.006). TTR and TV correlated with symptoms (grittiness, R2=-0.641, p=0.034; discomfort, R2=-0.667, p=0.025), central staining (R2=-0.647, p=0.031) and CS (R2=-0.656, trend only, p=0.07). TTR was more related to discomfort than ST in a multivariate model (p=0.01). 7 subjects (63.6%) had MG dysfunction. Lid signs were correlated to each other, but to signs/symptoms of dry eye in an unexpected direction: better lid health correlated to higher grittiness (R2=0.657, p=0.028), higher total symptoms (R2=0.62, p=0.042); worse lid redness (R2=0.81, p=0.0025) and lower lid gland secretions (SC: R2=0.611, p=0.046;SV: R2=0.779, p=0.005) correlated with better ST. TTR behaved similar to ST: better rates/volumes with worse lid health. Upper/ lower lids were not correlated.
Conclusions
In these dry eye subjects, 7 had lid gland dysfunction. Many signs, symptoms and function tests were correlated. TTR was more correlated with symptoms and may be a more relevant endpoint than ST. Younger subjects had higher symptom scores. These data indicated a strong relationship within subjects between signs, symptoms and QoL of dry eye, including TTR, yet lid glands correlated in unexpected ways to signs/symptoms, suggesting a compensatory mechanism may underlie these results. These data will be expanded in a large-scaled study.