Evaluation of subjective assessments and objective diagnostic tests for diagnosing tear-film disorders known to cause ocular irritation.

PURPOSE: To determine which subjective assessments and objective tests have clinical utility as diagnostic tools in ocular irritation associated with Sjögren's syndrome-related aqueous tear deficiency (ATD), non-Sjögren ATD, inflammatory meibomian gland disease (MGD) associated with rosacea, and atrophic MGD. METHODS: Forty adults with ocular irritation and 10 with normal ocular surfaces were enrolled in a nonrandomized, nonblinded clinical trial. Symptoms were evaluated. Tests included biomicroscopy; evaluation of tear-film integrity, production, and clearance; fluorescein and rose bengal staining; and serum autoantibody screening. RESULTS: Symptoms were similar among groups and most severe in the Sjögren's group. Fluorescein tear break-up time was significantly faster in the ATD and MGD groups than that in controls. Schirmer scores were significantly lower in the ATD group than those in MGD and control groups. Tear clearance was delayed in the ATD and atrophic MGD groups. Xeroscope grid distortion was noted only with ATD. The Sjögren's group had greater loss of naso-lacrimal reflex, slower fluorescein clearance, and greater ocular-surface fluorescein and rose bengal staining than did the others. More MGD subjects had meibomian gland orifice metaplasia and acinar dropout than did those with Sjögren-related ATD and controls. Schirmer scores correlated inversely with rose bengal staining, corneal fluorescein staining, and grid distortion. Rose bengal staining correlated with grid distortion and loss of nasal-lacrimal reflex, but not with MGD. CONCLUSION: Subjective assessments and objective diagnostic tests have clinical utility as diagnostic tools in tear-film disorders. ATD is correlated with ocular-surface disease. An algorithm summarizing the diagnostic utility of these tests is included.

Pseudo-loss of fixation in automated perimetry.

During automated perimetry with the Humphrey Visual Field Analyzer, field examinations are labeled unreliable whenever the reported rate of fixation loss is 20% or more. The reported rate of fixation loss results in part from times when the patient's gaze drifts from the fixation point during the examination, but also in part from technical artifacts such as faulty initial localization of the blind spot or false-positive responses by the patient. It was found that technical artifacts caused nearly half of the instances in which a field examination had a reported fixation loss rate of greater than 20%. It was also found that the perimetrist can prevent the artifacts, with the result that the frequency of field examinations labeled as having excessive fixation loss fell from 26% to 14%.