Correlation of the Schirmer 1 and fluorescein clearance tests with the severity of corneal epithelial and eyelid disease

Objective: To evaluate the correlations of the fluorescein clearance test ( FCT) and the Schirmer 1 test with the severity of corneal epithelial and ey elid disease in normal patients and patients with tear film disorders due t o meibomian gland disease (MGD) and/or aqueous tear deficiency (ATD). Methods: Nineteen normal control subjects, 16 patients with MGD associated with rosacea, 21 patients with noninflammatory atrophic MGD, and 43 patient s with ATD were enrolled. There was a similar age and sex distribution in e ach group. Each patient completed a symptom severity questionnaire that con sisted of 11 questions and then underwent a panel of diagnostic tests in th e following order: assessment of corneal and conjunctiva sensation with the Cochet-Bonnet esthesiometer, FCT, assessment of corneal fluorescein staini ng, Schirmer 1 test (5 minutes without anesthesia), and biomicroscopic exam ination of the eyelid margins and meibomian glands. The FCT was performed w ith a fluorophotometer by measuring the fluorescein concentration in minima lly stimulated tear samples collected from the inferior tear meniscus. By s tudying the best area under the receiver operating characteristic curves, w e developed a formula that combined the FCT and Schirmer test results, whic h we termed the FCT corrected by Schirmer test. Results: The FCT showed stronger correlation with ocular irritation symptom s (r=0.35, P <.001), corneal fluorescein staining (r=0.54, P<.001), and mei bomian gland and eyelid pathologic signs than the Schirmer 1 test. A correc tion factor that was based on the best area under the receiver operating ch aracteristic curves, added to the FCT score, improved its correlation with ocular irritation symptoms, eyelid margin and meibomian gland pathologic si gns, and ocular surface sensitivity scores. Conclusions: Corneal epithelial disease is correlated with decreased aqueou s tear production and delayed tear clearance, whereas eyelid and MGD are co rrelated with delayed tear clearance. The FCT corrected by Schirmer 1 test improves the correlations of the FCT with ocular irritation symptoms, corne al epithelial and eyelid pathologic signs, and corneal and conjunctival sen sitivity for patients with MGD and ATD.