Preliminary Application of a Continuous Functional Contrast Visual Acuity System in the Assessment of Visual Function in Dry Eye Patients.

Purpose: To investigate the feasibility and efficacy of a continuous functional contrast visual acuity (CFCVA) system in the assessment of visual function in dry eye disease (DED). Methods: Twenty patients with DED and 15 normal controls were recruited. Subjective symptoms were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, and tear film stability was assessed by a noninvasive corneal topographer. Under natural blinking conditions, the custom-built CFCVA system was used to take serial visual acuity measurements at 100%, 25%, 10%, and 5% contrast for 60 seconds. A 5-minute measurement at a 100% contrast level was defined as the stress test (ST). Mean CFCVA was defined, and visual maintenance ratio (VMR) was the ratio of mean CFCVA divided by baseline visual acuity. Results: In both groups, VMR decreased and mean CFCVA (logarithm of the minimum angle of resolution) increased with decreasing optotype contrast (from 100% to 5%). In ST, the ST VMR at the fourth and fifth minutes (VMR54 and VMR55) showed the strongest correlations with OSDI total, ocular symptoms, and vision-related function (-0.646 and -0.598, -0.688 and -0.693, and -0.599 and -0.555, respectively, P < 0.05). VMR54 and VMR55 also demonstrated the best discriminating ability for detecting DED, with areas under the curve of 0.903 and 0.867, respectively. Conclusions: Extending the continuous measuring time was more effective for detecting vision-related functional abnormalities in patients with DED than simply decreasing the optotype contrast level. Translational Relevance: The proposed CFCVA system and associated parameters offer a potential method for quantifying and interpreting the visual symptoms of DED in clinical care.

Comparison of Refractive Prediction Accuracy With Three Optical Devices.

PURPOSE: To investigate refractive prediction accuracy with the OA-2000 (Tomey), Anterion (Heidelberg Engineering), and IOLMaster 500 (Carl Zeiss Meditec AG) in patients with cataract. METHODS: Patients with cataract referred for phacoemulsification were enrolled and scanned with the OA-2000, Anterion, and IOLMaster 500 in random order. The success rate of axial length (AL) measurements per device was calculated and a chi-square test was used to identify the differences in acquisition rate between the three devices. The Bland-Altman method was used to appraise the agreement of biometric parameters between the three devices. Four different formulas (Barrett Universal II [BUII], Haigis, Holladay 1, and SRK/T) were included in the study. The parameters of refractive prediction accuracy comprised predictive error (PE), absolute PE (AE), and percentages of eyes with a PE within ±0.50, ±0.75, and ±1.00 diopters (D). RESULTS: The acquisition rates of AL measurements with the OA-2000 and Anterion were 97.35% and 94.70%, respectively (chi-square = 3.82, P > .05). A significantly lower acquisition rate of 84.82% was obtained with the IOLMaster 500 compared with the other two devices (P < .05). Bland-Altman analysis identified good agreement between the three biometers with narrow 95% limits of agreement for flat and steep keratometry (K1 and K2), anterior chamber depth (ACD), and AL. For PE, only the differences between the Anterion and IOLMaster 500 with the Barrett UII and Haigis formulas were statistically significant (P < .05). The three devices revealed no statistically significant differences in MAE, MedAE, and the proportion of eyes with a PE within ±0.50, ±0.75, and ±1.00 D (P > .05). CONCLUSIONS: The OA-2000 and Anterion showed a similarly higher acquisition rate of AL measurements than the IOLMaster 500 in patients with cataract. Good agreement for K1, K2, ACD, and AL was found between the three biometers. Regarding refractive prediction accuracy, the Anterion did not significantly outperform both the OA-2000 and IOLMaster 500. [J Refract Surg. 2023;39(1):48-55.].