A standardized visual scale for evaluation of tear fluorescein clearance

Objective: To evaluate the correlation and the agreement between a validate d fluorometric technique (fluorescein clearance test) and a newly developed , clinically practical standardized visual scale to evaluate tear fluoresce in clearance. Also, the ability of this new method to distinguish healthy p ersons from patients reporting ocular irritation associated with meibomian gland disease (MGD), aqueous tear deficiency (ATD), or both was tested. Design: Case-controlled study. Participants: Healthy persons (n = 32), patients with MGD associated with r osacea (n = 30), patients with noninflammatory atrophic MGD (n = 24), and p atients with ATD (n = 39) were evaluated. There was a similar age and gende r distribution in each group. Methods: Each subject completed a symptom questionnaire and had the followi ng tests performed: fluorescein clearance test (FCT), standardized visual s cale test (SVST), corneal fluorescein staining, Schirmer 1 test, corneal an d conjunctiva sensitivity, and eyelid margin and meibomian gland examinatio n. Main Outcome Measures: The FCT was performed with a CytoFluor II fluorophot ometer by measuring the fluorescein concentration in minimally stimulated t ear samples collected from the inferior tear meniscus 15 minutes after inst illation of 5 mu l of 2% sodium fluorescein. The SVST score, ranging from 0 to 6, was obtained by comparing the colors of the standardized visual scal e with the color of the lateral inferior tear meniscus immediately before t ear collection for the FCT. Severity of ocular irritation was assessed with a symptom questionnaire. Schirmer 1 test (without anesthesia), biomicrosco pic meibomian gland evaluation, and corneal fluorescein staining were perfo rmed. Corneal and conjunctival sensitivity scores were assessed with the Co chet-Bonnet aesthesiometer. The correlation and the agreement between FCT, FCT corrected for Schirmer test (corrected FCT), SVST, and SVST corrected f or Schirmer test (corrected SVST) in separating healthy persons from patien ts with ATD, MGD, or both were studied. Furthermore, the correlations of FC T, corrected FCT, SVST and corrected SVST, corneal fluorescein staining sco re, corneal and conjunctiva sensitivity, meibomian gland and eyelid evaluat ion, and questionnaire score were studied. Results: The FCT, the corrected FCT, the SVST, and the corrected SVST all s howed strong correlation with irritation symptoms, corneal fluorescein stai ning, Schirmer 1 test score, cornea and conjunctiva sensitivity, and meibom ian gland and eyelid pathologic characteristics. The FCT, the corrected FCT , the SVST, and the corrected SVST had a sensitivity in diagnosing MGD, res pectively, of 67%, 72%, 69%, and 76%, and of 95%, 97%, 97%, and 97% in diag nosing ATD. The specificity was, respectively, 97%, 96%, 97%, and 94%. Conclusions: The new standardized visual scale test was equivalent to fluor ometric assessment of tear clearance in its correlation with irritation sym ptoms, ocular surface and eyelid disease, and ocular surface sensitivity. I ts ability to separate healthy persons from patients with MGD and ATD was i mproved by applying a correction factor based on Schirmer test score. The n ew standardized visual scale test is an accurate and practical method for c linical assessment of fluorescein tear clearance. (C) 2000 by the American Academy of Ophthalmology.