Diagnosing, monitoring dry eye an inconsistent science

Patient-reported symptoms of dry eye are moderately repeatable from visit to visit, but several key procedures used to diagnose and monitor dry eye are largely unrepeatable, according to a study published in Cornea.

Kelly K. Nichols, OD, MPH, PhD, and colleagues at The Ohio State University College of Optometry performed dry eye examinations on 75 patients on two separate occasions to assess the repeatability of dry eye tests. All patients were seen by a single examiner at both visits.

The examinations included symptom assessment, contact lens and medical history, slit-lamp biomicroscopic evaluation of the eyelids, evaluation of meibomian glands, assessment of tear film quality, tear meniscus height, assessment of blink quality, fluorescein tear breakup time, fluorescein and rose bengal staining of the cornea and conjunctiva, phenol red thread test and Schirmer test.

Subjective reports of dryness and grittiness had moderate to high repeatability. But the repeatability of meibomian gland disease classification, presence or absence of inferior corneal fluorescein staining and inferior conjunctival rose bengal staining was poor, the researchers found. When the summed staining score of the corneal and conjunctival regions was evaluated, the weighted reliability was fair. Tear breakup time repeatability was substantial, and the repeatability improved when the two timed reading were averaged.

Schirmer testing was more variable as wetting scores increased. When average Schirmer scores were less than 10 mm, only moderate repeatability was demonstrated. The study authors suggested that the Schirmer test performs best with more advanced dry eye.

The study is published in the April issue of Cornea.