Correlations Among Symptoms, Signs, and Clinical Tests in Evaporative-Type Dry Eye Disease Caused by Meibomian Gland Dysfunction (MGD)

Purpose: To evaluate changes in symptoms, objective tests, and signs after medical treatment of subjects with evaporative-type dry eye disease (EDE) caused by Meibomian gland dysfunction (MGD), and to analyze correlations among symptoms, signs and test results in the worse eyes (W-eyes) of the subjects. Methods: Prospective clinical study of 21 symptomatic subjects with EDE caused by MGD. Subjects who were diagnosed with EDE in a first visit were treated for 6 weeks and re-evaluated in a second visit. The differences between initial and second visits were evaluated. Correlations among clinical symptoms, signs, and test results were performed using the data of the W-eyes. Variables evaluated included: dry eye symptoms, best corrected visual acuity (BCVA), contrast sensitivity, conjunctival hyperemia, phenol red thread test, tear break-up time (TBUT), tear meniscus height (TMH), corneal fluorescein and conjunctival rose Bengal staining, tear lysozyme concentration, Schirmer test, and lid margin assessment. Results: All items evaluated improved after treatment, but only conjunctival hyperemia and TMH improved significantly. TBUT and lid margin changes improved, but still remained abnormal. There were significant correlations among symptoms questionnaires and some clinical tests (TBUT, conjunctival hyperemia, TMH, and conjunctival rose Bengal staining). Conclusion: Despite the instability of the tear film and lid margin alterations that continued after treatment, subjects with MGD improved symptomatically. The low degree of correlations among W-eye signs, symptoms, and tests reflects the independency of symptoms and signs in this complex pathology.