Noninvasive assessment of tear stability with the tear stability analysis system in tear dysfunction patients

PURPOSE

To evaluate tear film stability in patients with tear dysfunction and an asymptomatic control group by using the novel, noninvasive Tear Stability Analysis System (TSAS).

METHODS

In this prospective case-control study, 45 patients with dysfunctional tear syndrome (DTS) were stratified into three groups (1, 2, and 3/4) based on clinical severity, with higher scores indicating more severe symptoms; 25 asymptomatic control subjects were evaluated. TSAS measurements were performed with the RT-7000 Auto Refractor-Keratometer (Tomey Corporation, Nagoya, Japan). Images of ring mires projected onto the cornea every second for 6 seconds were captured and analyzed. Focal changes in brightness were calculated as numerical ring breakup (RBU) values, and the elapsed time when the cumulative values (RBU sum) exceeded a threshold was defined as the ring breakup time (RBUT).

RESULTS

RBUTs in the DTS groups were all significantly lower than those in the control subjects, with the lowest values found in DTS 3/4. RBUT was significantly shorter in DTS 3/4 than in DTS 1 (P<0.001). The change in RBU sum over a 6-second period in the DTS groups combined or between the individual groups was statistically significant (P<0.001), as was the difference between the 1- and 6-second values. For distinguishing between asymptomatic controls and DTS, the sensitivity and specificity of a 5.0-second RBUT cutoff were 82.0% and 60.0%, respectively.

CONCLUSIONS

The TSAS may be a useful, noninvasive instrument for evaluating tear stability and for classifying DTS severity.

Anterior segment optical coherence tomography: a diagnostic instrument for conjunctivochalasis

PURPOSE

To evaluate cross-sectional areas of conjunctivochalasis and tear meniscus using Fourier-Domain RTVue-100 optical coherence tomography (OCT) before and after conjunctival cauterization and to evaluate inter- and intraobserver reliability.

DESIGN

Prospective, nonrandomized, consecutive case study.

METHODS

A total of 12 eyes of 7 patients with conjunctivochalasis (aged 56 to 87) were evaluated. After topical anesthesia, conjunctival cauterization was performed on the inferior bulbar conjunctiva. All patients underwent anterior segment OCT (AS-OCT) imaging prior to and 4 weeks after the procedure. Cross-sectional tear meniscus and conjunctivochalasis areas at 3 locations (nasal, center, and temporal areas) were measured in all patients.

RESULTS

Nonsignificant increases (P = .177) in cross-sectional tear meniscus area as a whole (3 locations combined) were observed following cauterization. Cross-sectional conjunctivochalasis area measurements significantly decreased in all 3 locations after cauterization (P < .001). Mean cross-sectional conjunctivochalasis area decreased from 0.247 ± 0.24 mm(2) to 0.054 ± 0.79 mm(2). For 2 measurements of cross-sectional tear meniscus area by examiner 1, intraclass correlation coefficients ranged from 0.998 to 0.999. Among 2 examiners, Cronbach's alpha reliability coefficients were as high as 0.993 and 0.997 before and after conjunctival cauterization. Regarding the cross-sectional conjunctivochalasis area measurements, intraclass correlation coefficient values were similar to those of the cross-sectional tear meniscus area, but Cronbach's alpha reliability coefficients were slightly less.

CONCLUSIONS

This study indicates the AS-OCT is a useful and reproducible instrument to measure the cross-sectional area of conjunctiva prolapsing into the tear meniscus of patients with conjunctivochalasis. The method can monitor effectiveness of thermoreduction of conjunctivochalasis.