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Purpose: To evaluate the keratometry agreement between two swept-source devices for healthy and post-refractive surgery eyes and compare them. Methods: One hundred volunteers between 20 and 55 years of age were recruited for this study including both healthy and post-refractive surgery eyes. Three consecutive measurements of simulated keratometry (Sim K), posterior keratometry (PK), and total keratometry (TK) were obtained with the IOLMaster 700 and Anterion. The agreement was assessed through the Bland-Altman method. Limits of agreement (LoA) were calculated as mean difference ±1.96·SD and it represents the 95% of the differences between devices. Results: For both groups, Sim K measurements exhibited a mean difference close to 0 and within a range of ±0.30 and ±0.36 diopters (D) for the control and post-refractive surgery groups, respectively. Meanwhile, the IOLMaster 700 provided flatter PK values (0.30 D on average) for both groups. In general, the post-refractive surgery group exhibited slightly greater mean differences and wider 95% LoA than the control group for Sim K and PK. Steeper TK values were obtained by the IOLMaster in both groups (control = 0.50 D and post-refractive surgery = 0.75 D). TK differences between devices were significantly greater in the post-refractive surgery group (ranging from 0.38 to 1.14 D) compared to the control group (ranging from 0.15 to 0.85 D). Conclusions: The IOLMaster 700 and Anterion are not interchangeable for TK measurements and eyes that had corneal refractive surgery even decreased the agreement between devices. Differences between devices for Sim K and PK measurements should be clinically judged, particularly in eyes with previous corneal surgery. [ J Refract Surg . 2023;39(5):347–353.]

Summary Objectives This study aims to evaluate the relationship between application of the MGDRx thermal eyebag and dry eye signs and symptoms in young and older subjects and to compare the results between the two groups. Methods Thirty young, healthily volunteers between 18 and 31 years of age (23.95 ± 3.94 years) and thirty older subjects between 61 and 90 years of age (77.97 ± 8.11 years) participated in this study. Ocular surface parameters were assessed using the Oculus Keratograph 5 M, following the guidelines of the Tear Film and Ocular Surface Dry Eye Workshop II Diagnostic Methodology report. Only subjects with a positive score on at least one questionnaire and an initial Non-Invasive Keratograph Break-Up Time (NIKBUT) under 10 seconds were included in the study. After thermal bag self-application in both eyes every day for 2 weeks, the protocol was carried out again. Lid massage was performed after lid warming. Compliance and degree of improvement were also assessed. Main results The young volunteer group showed an improvement in NIKBUT, lipid layer score, upper eyelid gland drop-out percentage and dry eye symptoms over the two week treatment period. Improvements in meibum quality, gland obstruction, telangiectasia scores, and dry eye symptoms were found in the older subjects. Mixed ANOVA revealed better NIKBUT and lipid layer values in the young subjects. Despite the treatment compliance being statistically higher in the older group than in the younger subjects (P = 0.002), there were no significant differences in subjective improvement between groups (P = 0.097). Conclusion Dry eye-related symptoms were improved after thermal bag application, while NIKBUT and lipid layer thickness were improved only in the younger subjects.

This study aims to assess the performance of an analysis method to measure in vivo the movement speed of tear film particles post-blink as a measure of tear film spreading. Ocular surface parameter...

The aim of this study is to develop a new objective semiautomatic method for analysing Meibomian glands visibility quantitatively.One hundred twelve healthy volunteers aged between 18 and 90 years (48.29 ± 27.46 years) participated in this study. Infrared meibography was obtained from the right upper eyelid through Oculus Keratograph 5 M. Meibographies were classified into 3 groups: Group 1 = patients with good subjective glands visibility and a gland dropout percentage 1/3 of the total Meibomian gland area; Group 2 = patients with low subjective glands visibility and a gland dropout 1/3; and Group 3 = patients with low subjective glands visibility and a gland dropout 1/3. New metrics based on the visibility of the Meibomian glands were calculated and later compared between groups. Rho Spearman test was used to assess the correlation between each metric, and Meibomian gland dropout percentage with the entire sample and after excluding Group 2. A p value less than 0.05 was defined as statistically significant.Fifty-six subjects were classified in Group 1 (24.48 ± 9.62 years), 19 in Group 2 (69.16 ± 21.30 years) and 37 in Group 3 (73.59 ± 13.70 years). No statistically significant differences were found between Groups 1 and 2 in dropout percentage. All metrics, with the exception of entropy, showed a higher Meibomian gland visibility in Group 1 than in the other two groups. Moderate correlations were statistically significant for all metrics with the exception of entropy. Correlations were higher after excluding Group 2.The proposed method is able to assess Meibomian gland visibility in an objective and repeatable way, which might help clinicians enhance Meibomian gland dysfunction diagnosis and follow-up treatment.

PURPOSE To assess the performance of a new device for the clinical determination of light discomfort on a large sample of healthy human subjects. METHODS A total of 489 subjects ranging from 20 to 70 years old (241 men, 248 women) were evaluated with the LUMIZ™ 100 to determine light discomfort. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Repeated measures ANOVA, Kruskal-Wallis, and correlation analysis were applied to test for differences between repeated measures, and effect of age on reliability. RESULTS Discomfort thresholds obtained are well distributed across the light intensity range available (25 to 10211 lux). Intrasession ICCs are higher than 0.849 for all thresholds, and 85% of CoV are below 10%. Thresholds obtained in the first set of measurements are highly correlated with the median of three sets (r2 > 0.8). Intersession, 64% of CoV are below 10%. Age does not affect discomfort thresholds (p = 0.30), nor affect reliability (variance on CoV, p = 0.368). CONCLUSIONS The new device provides good intrasession repeatability for the clinical determination of light discomfort thresholds, although variance is slightly greater between sessions. The system is useful for the clinical determination of light discomfort.

SIGNIFICANCE The diagnosis of dry eye disease and meibomian gland dysfunction (MGD) is challenging. Measuring meibomian gland visibility may provide an additional objective method to diagnose MGD. PURPOSE This study aimed to evaluate the ability of new metrics to better diagnose MGD, based on measuring meibomian gland visibility. METHODS One hundred twelve healthy volunteers (age, 48.3 ± 27.5 years) were enrolled in this study. Ocular surface parameters were measured using the Oculus Keratograph 5M (Oculus GmbH, Wetzlar). Subjects were classified according to the presence or absence of MGD. New metrics based on the visibility of the meibomian glands were calculated and later compared between groups. The diagnostic ability of ocular surface parameters and gland visibility metrics was studied through receiver operating characteristic curves. Logistic regression was used to obtain the combined receiver operating characteristic curve of the metrics with the best diagnostic ability. RESULTS Statistically significant differences were found between groups for all ocular surface parameters and new gland visibility metrics, except for the first noninvasive keratograph breakup time and gland expressibility. New gland visibility metrics showed higher sensitivity and specificity than did current single metrics when their diagnostic ability was assessed without any combination. The diagnostic capability increased when gland visibility metrics were incorporated into the logistic regression analysis together with gland dropout percentage, tear meniscus height, dry eye symptoms, and lid margin abnormality score (P < .001). The combination of median pixel intensity of meibography gray values and the aforementioned ocular surface metrics achieved the highest area under the curve (0.99), along with excellent sensitivity (1.00) and specificity (0.93). CONCLUSIONS New meibomian gland visibility metrics are more powerful to diagnose MGD than current single metrics and can serve as a complementary tool for supporting the diagnosis of MGD.

Background We aim to assess if refractive error or age may influence the repeatability of measurements using a swept-source biometer. Methods A total of 61 subjects were evaluated with IOLMaster 700 acquiring measurements of axial length (AL), central corneal thickness (CCT), white-to-white distance (WTW), anterior aqueous depth (AQD), lens thickness (LT), and keratometry (K) readings. Repeatability was evaluated classifying the sample according to the refractive state and age by the calculation of the within-subject standard deviation (Sw), coefficient of repeatability, and intraclass correlation coefficient. Results Very similar Sw was acquired among groups for AL, CCT, and WTW. Differences found for AQD, LT, keratometry and astigmatism among refractive and age groups were not clinically significant. Refractive groups obtained a Sw for AQD between 0.016 and 0.026, while for LT was between 0.023 and 0.029 mm. Besides, Sw showed values from 0.014 to 0.029 mm for keratometry. Age groups obtained a Sw of 0.025 and 0.016 mm for AQD, and 0.029 and 0.018 mm for LT, respectively. Sw was 0.019 vs 0.018 mm for K1, 0.014 vs 0.031 mm for K2. Conclusions IOLMaster 700 showed good repeatability for biometric and keratometric parameters in eyes classified according to their refractive error or age.

Current advances in ocular surgery require the evaluation of differences in automated white-to-white (WTW) measurements between systems. We aim to analyze three different commonly used devices in clinical practice: the IOLMaster 700, the Atlas 9000, and the Sirius.Ninety right eyes of ninety healthy subjects were included. Measurements of WTW distances were taken with each device for all subjects in the same session and by the same observer. Statistical comparison was carried out by means of the rANOVA procedure and the Bonferroni post-hoc test. In addition, the Bland-Altman analysis was applied in order to perform pairwise comparisons.Average WTW values obtained by the IOLMaster 700, the Atlas 9000, and the Sirius devices were 12.18 ± 0.40-mm, 12.32 ± 0.37-mm and 11.90 ± 0.37-mm, respectively. There were statistically significant differences in all pairwise comparisons. Mean differences revealed that the Atlas 9000 provided the highest WTW values, followed by the IOLMaster 700 values and finally by the Sirius results, which had the lowest values. The limits of agreement obtained in all pairwise comparisons were wide, with a range between 0.64 and 0.75 mm.According to our results, these three devices should not be used interchangeably for WTW diameter measurements during the clinical practice.

Purpose To assess the links between discomfort glare sensitivity and physiological factors such as eye biometry, refraction, skin phototype, age, and gender among a large sample of healthy human subjects. Methods A total of 489 participants who were 20 to 70 years old (241 men, 248 women) underwent discomfort glare threshold measurements via the LUMIZ 100. Eye biometry and optical quality were measured using a Zeiss IOLMaster 700 biometer and i.Profiler aberrometer. Iris color, skin tone, age, gender, eyeglasses use, chronotype, fatigue level, self-evaluation of light sensitivity, and time spent outdoors were determined. Statistical analysis was carried out using nonparametric Mann–Whitney and Kruskal–Wallis tests for categorical data and correlation coefficients for numerical data. Results The female subgroup had lower discomfort thresholds than the males (P < 0.001). There was no effect of age group, ametropia, eye biometry, iris color, skin tones, chronotype, or fatigue level on discomfort thresholds. Discomfort thresholds were related to self-assessment of light sensitivity, sunglasses ownership, and frequency of use (P < 0.001). Conclusions Exploration of easily measurable physiological parameters and questionnaire failed to provide reliable indicators of individual light sensitivity to discomfort glare. Translational Relevance Light sensitivity is highly subjective and variable across the population. Patients frequently complain about light bothering their daily lives. Accessible physiological factors and questionnaires are unable to predict discomfort levels due to glare. The LUMIZ 100 provides a reliable, rapid, and safe way to determine light discomfort thresholds in order to better manage light sensitivity in clinical care.

Current advances in refractive surgery require high accuracy of corneal measurements. We aim to evaluate the repeatability of topographic measurements using an integrated Placido disk - OCT device.Thirty right eyes of thirty healthy and young subjects were included. The topographic parameters of simulated keratometry, asphericity, minimum pachymetry, white-to-white distance, spherical aberration and corneal elevation were studied. Three measurements were taken by the same observer using the Visante omni device. The coefficient of repeatability (CoR), coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the repeatability. The Bland-Altman graphical method was also applied.No significant differences between repeated measurements were found. The mean difference for simulated keratometry was between 0.01 and 0.02 D. For asphericity was -0.01 ± 0.02, and for minimum pachymetry, spherical aberration and WTW was equal or less than 0.02 mm. The mean differences for corneal elevation, in millimeters and diopters, were between 0.00 and 0.01. Overall, most topographic parameters had a CoV less than 0.4%, a CoR less than 0.3 and an ICC higher than 0.98.The Visante omni device provides good repeatability for topographical measurements of simulated keratometry, asphericity, pachymetry, spherical aberration and corneal elevation.

Objectives: To investigate the ocular surface of an aged population wearing a daily disposable contact lens over their first day of wear. Methods: Forty eyes from forty presbyopic subjects were fitted a daily CL (Delefilcon A). Tear osmolarity, tear meniscus area (TMA) and ocular surface aberrations (total higher order root means square (RMS)) were assessed at baseline (t0), at 20 minutes (t1) and after 8 hours (t2) of wear. Fluorescein corneal and conjunctival staining and tear break up time (TBUT) were performed at t0 and t2. Results: No statistically significant changes were found between t0, t1 and t2 for TMA, and between t0 and t2 for fluorescein corneal and conjunctival staining. TBUT worsened by the end of the day from 10.4±0.4 seconds t0 to 9.0±0.3 seconds t2 (P

Purpose: To assess the relationship between the corneal biomechanical parameters and the anterior segment parameters in Caucasian children. Methods: This study included 293 eyes from 293 healthy children aged between 6 and 17 years. Corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer, axial length (AL) with IOLMaster and the anterior segment with Pentacam. Anterior segment parameters obtained were the following: central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and mean anterior and posterior keratometry. Two multiple linear regression models were constructed to assess the association between CH and CRF with anterior segment parameters. A value of p < 0.05 was taken as the criterion for statistical significance in all analyses. Results: The mean CH and CRF were 12.12 +/- 1.71 and 12.30 +/- 1.89 mmHg, respectively. Multiple linear regression revealed that CH and CRF were associated negatively with AL in both models, and positively with CCT and CV in the first and second model, respectively. Meanwhile ACD, ACV or mean keratometry did not correlated with CH and CRF. Moreover, when CCT was in the model, it explained more variability for both CH (22.1%) and CRF (30.9%) than when CV was included (16.2% for CH and 16.5% for CRF). Conclusions: CH and CRF were correlated positively with CCT and CV, and negatively with AL in healthy Caucasian children. Moreover, corneal parameters were the most contributory variables to CH and CRF changes.