Quantifying Meibomian Gland Morphology Using Artificial Intelligence.

SIGNIFICANCE: Quantifying meibomian gland morphology from meibography images is used for the diagnosis, treatment, and management of meibomian gland dysfunction in clinics. A novel and automated method is described for quantifying meibomian gland morphology from meibography images. PURPOSE: Meibomian gland morphological abnormality is a common clinical sign of meibomian gland dysfunction, yet there exist no automated methods that provide standard quantifications of morphological features for individual glands. This study introduces an automated artificial intelligence approach to segmenting individual meibomian gland regions in infrared meibography images and analyzing their morphological features. METHODS: A total of 1443 meibography images were collected and annotated. The dataset was then divided into development and evaluation sets. The development set was used to train and tune deep learning models for segmenting glands and identifying ghost glands from images, whereas the evaluation set was used to evaluate the performance of the model. The gland segmentations were further used to analyze individual gland features, including gland local contrast, length, width, and tortuosity. RESULTS: A total of 1039 meibography images (including 486 upper and 553 lower eyelids) were used for training and tuning the deep learning model, whereas the remaining 404 images (including 203 upper and 201 lower eyelids) were used for evaluations. The algorithm on average achieved 63% mean intersection over union in segmenting glands, and 84.4% sensitivity and 71.7% specificity in identifying ghost glands. Morphological features of each gland were also fed to a support vector machine for analyzing their associations with ghost glands. Analysis of model coefficients indicated that low gland local contrast was the primary indicator for ghost glands. CONCLUSIONS: The proposed approach can automatically segment individual meibomian glands in infrared meibography images, identify ghost glands, and quantitatively analyze gland morphological features.

Not All Dry Eye in Contact Lens Wear Is Contact Lens-Induced.

OBJECTIVES: To compare subjective and clinical outcomes in three study groups: (1) asymptomatic contact lens (CL) wearers (ASYM); (2) symptomatic CL wearers who become asymptomatic on lens removal; and (3) symptomatic CL wearers who do not resolve on lens removal. METHODS: Ninety-two subjects completed the Berkeley Dry Eye Flow Chart with and without lenses, ocular surface examinations, and a battery of questionnaires. RESULTS: Thirty-seven subjects (40%) were ASYM, 30 (33%) had contact lens-induced dry eye (CLIDE), and 25 (27%) had underlying physiological DE. Visual Analog Scale ratings, OSDI score, and SPEED score were significantly better for the ASYM group (P<0.001) but did not distinguish CLIDE from DE. The DE group was significantly worse than CLIDE and ASYM, which were similar, in precorneal noninvasive tear breakup time (8.2 sec DE vs. 12.3 sec CLIDE and 14.3 sec ASYM; P=0.002), anterior displacement of the Line of Marx (P=0.017), and superior conjunctival staining (P=0.001). CONCLUSIONS: Many CL wearers presenting with dryness symptoms have an underlying DE condition and will not respond to treatments aimed at changing lenses or solutions. Contradictory results from research studies of DE in CL wearers could be due in part to a failure to distinguish subjects with symptoms due specifically to CL wear from those whose symptoms have underlying causes unrelated to CL wear.

Ocular Surface Cooling Corresponds to Tear Film Thinning and Breakup.

PURPOSE: To investigate the relationship between ocular surface temperature (OST) and tear film thinning and breakup. METHODS: Simultaneous imaging of OST and fluorescein tear thinning and breakup (FTBU) was performed on 20 subjects. Subjects were asked to open their eyes and refrain from blinking for as long as they could during testing. Ocular surface temperature was measured using an infrared thermographic camera (FLIR A655sc) and rates of ocular surface cooling (OSC) were analyzed using commercially available software. A method was developed to quantify the rate of FTBU formation using image-processing software. RESULTS: Areas of FTBU and regions of OSC were observed to be colocalized, with localized cooling preceding the formation of FTBU. The rates of OSC and FTBU formation were positively correlated (r = 0.74). A second-order polynomial model accurately describes the physiological relationship between the area of FTBU and OST (p < 0.001). A linear approximation provides a more clinically interpretable rate of FTBU formation with decreasing OST (p < 0.001), while still retaining high R. CONCLUSIONS: The results suggest a direct relationship between FTBU formation and OSC. That cooling of the ocular surface precedes FTBU formation implies a process of evaporation contributing to tear film thinning and breakup. Our study suggests that measuring the OSC rate could be an indirect assessment of tear evaporation and could contribute to the management of evaporative dry eye.

Relationships among Tear Film Stability, Osmolarity, and Dryness Symptoms.

PURPOSE: To examine the relationships among tear osmolarity, tear film stability, and several measures of dry eye (DE) symptoms in a multivariable analysis. METHODS: A cross-sectional study was conducted with 137 subjects (68 non-contact lens [CL] wearers and 69 soft CL wearers) recruited from a university campus. Tear breakup time (TBUT) was measured noninvasively (NITBUT) and with fluorescein (FTBUT). Tear osmolarity was measured by an osmometer. Dry eye symptoms were assessed using the Dry Eye Flow Chart and several different questionnaires. RESULTS: Subjects ranged in age from 18 to 67 years, with a mean of 28 years. Subjects had a mean (SD) osmolarity of 293 (10) mOsm/L, NITBUT of 14.1 (10.9) seconds, and FTBUT of 14.8 (12.6) seconds. Shorter NITBUT and FTBUT were significantly associated with female sex (p = 0.001 and p = 0.027, respectively) and Asian ethnicity (p = 0.030 and p = 0.004, respectively). There were no clinically significant relationships between tear osmolarity and FTBUT, NITBUT, or DE symptoms. Higher Dry Eye Flow Chart score (i.e., worse symptoms) was associated with older age (p < 0.001), female sex (p = 0.014), CL wear (p < 0.001), shorter NITBUT (p < 0.001), and shorter FTBUT (p = 0.028). The sensitivities and specificities for using clinical measurements to diagnose moderate to severe DE were as follows: osmolarity, 0.67 and 0.46, respectively; NITBUT, 0.72 and 0.52, respectively; and FTBUT, 0.68 and 0.57, respectively. CONCLUSIONS: In a population of asymptomatic, mild and moderate DE patients, increased tear osmolarity was not significantly associated with reported symptom severity and frequency. Tear osmolarity, NITBUT, and FTBUT exhibited similar sensitivities and specificities when used to diagnose moderate to severe DE.

Factors in contact lens symptoms: evidence from a multistudy database.

PURPOSE: This study aimed to examine the effects of demographic, lens performance, and ocular surface response measures on contact lens-related discomfort and dryness, using a large contact lens study database. METHODS: A total of 4164 records were extracted from a database of 220 subjects participating in 46 silicone hydrogel contact lens studies. Subjects discontinued lens wear for 24 hours and were then fit with either comfilcon A or enfilcon A lenses. The fit and performance of the lenses, along with subjective comfort and dryness, were assessed on insertion and after 3 and 6 hours of wear. After 6 hours of wear, ocular surface health was also assessed by fluorescein slitlamp examination. RESULTS: Decreased comfort at 3 hours after insertion was associated with excessive lens movement (p < 0.001), front surface deposits (p = 0.004), poor wettability (p = 0.014), and Asian ethnicity (p < 0.001). After 6 hours of wear, decreased comfort remained associated with greater lens movement (p = 0.032) and Asian ethnicity (p < 0.001), along with inferior corneal staining (p < 0.001). Dryness after 3 hours of wear was associated with greater lens movement (p < 0.001), Asian ethnicity (p < 0.001), increased deposits (p < 0.001), and poor wettability (p < 0.001). Dryness after 6 hours of wear remained associated with greater lens movement (p < 0.001) and Asian ethnicity (p < 0.001), along with inferior corneal staining (p < 0.001) and inferior lens decentration (p = 0.001). CONCLUSIONS: Excessive lens movement, inferior lens decentration, poor surface wettability and deposits, inferior corneal staining, and Asian ethnicity are associated with discomfort and dryness. Clinicians should consider all these factors to achieve the most comfortable and successful contact lens fit.

A novel analytical method using OCT to describe the corneoscleral junction.

PURPOSE: To develop and test a novel quantitative method of describing the corneoscleral junction, including metrics that reflect both the angle and the topography in this region of the ocular surface. METHODS: Forty-eight neophyte subjects were recruited (16 Asian, 16 white, and 16 Latino). Optical coherence tomography images of the nasal, temporal, superior, and inferior quadrants in both eyes were taken. Custom image analysis software was written in Matlab to allow the observer to select a point defining the center of the junction, from which 20 concentric circles were automatically drawn. The surface of the junction in the image was automatically located by edge-detection routines, and the circles intersecting this edge defined a series of points in the Cartesian plane. A linear regression was fit to these points, and a set of metrics based on the regression residuals was calculated. RESULTS: The sum of the squared orthogonalized residuals (SSRo) was the most repeatable metric and had the advantage of being unaffected by the orientation of the image. The SSRo was significantly greater in the nasal quadrant (p < 0.001), reflecting a more pronounced angle and/or rougher surface. The flattest and smoothest topography was found in the temporal quadrant. Whites had significantly higher SSRo than Asians and Latinos (p < 0.001). CONCLUSIONS: This study presents a novel metric for characterizing the angle and topography of the corneoscleral junction using optical coherence tomography and establishes differences among quadrants and between ethnic groups.

Contact lens care solutions: a pilot study of ethnic differences in clinical signs and symptoms.

OBJECTIVES: To determine whether Asian and white subjects differ in clinical signs or subjective symptoms in response to the use of different biguanide-preserved contact lens care solutions. METHODS: Forty-two subjects (15 Asian and 27 white) wearing lotrafilcon B silicone hydrogel contact lenses used a preservative-free lens care solution bilaterally for 2 weeks, then used two biguanide-preserved solutions (solution 1: ReNu MPS; solution 2: AQuify MPS) contralaterally in randomly assigned eyes for 4 weeks. Comprehensive ocular surface examinations were performed and symptomatology questionnaires were administered every 2 weeks. Investigators were masked as to solution assignment during examinations, whereas subjects were not to avoid potential difficulties in compliance with the protocol. RESULTS: With solution 1, most Asian and white subjects had grade 2 or greater corneal staining after 2 weeks (67% and 59%, respectively) and 4 weeks (60% and 67%, respectively). With solution 2, grade 2 or greater corneal staining occurred in 40% of Asians after 2 weeks and in 13% after 4 weeks, but in only 4% of whites after 2 weeks and 0% after 4 weeks. Whites reported significantly better average comfort (P=0.046) and less dryness (P<0.001) than did Asians. CONCLUSIONS: Asians and whites differ in both ocular response to the use of contact lens care solutions and in reporting subjective symptoms. Racial and ethnic differences should be considered when evaluating and treating contact lens patients in a clinical setting.

Enhancing Meibography Image Analysis Through Artificial Intelligence-Driven Quantification and Standardization for Dry Eye Research.

Purpose: This study enhances Meibomian gland (MG) infrared image analysis in dry eye (DE) research through artificial intelligence (AI). It is comprised of two main stages: automated eyelid detection and tarsal plate segmentation to standardize meibography image analysis. The goal is to address limitations of existing assessment methods, bridge the curated and real-world dataset gap, and standardize MG image analysis. Methods: The approach involves a two-stage process: automated eyelid detection and tarsal plate segmentation. In the first stage, an AI model trained on curated data identifies relevant eyelid areas in non-curated datasets. The second stage refines the eyelid area in meibography images, enabling precise comparisons between normal and DE subjects. This approach also includes specular reflection removal and tarsal plate mask refinement. Results: The methodology achieved a promising instance-wise accuracy of 80.8% for distinguishing meibography images from 399 DE and 235 non-DE subjects. By integrating diverse datasets and refining the area of interest, this approach enhances meibography feature extraction accuracy. Dimension reduction through Uniform Manifold Approximation and Projection (UMAP) allows feature visualization, revealing distinct clusters for DE and non-DE phenotypes. Conclusions: The AI-driven methodology presented here quantifies and classifies meibography image features and standardizes the analysis process. By bootstrapping the model from curated datasets, this methodology addresses real-world dataset challenges to enhance the accuracy of meibography image feature extraction. Translational Relevance: The study presents a standardized method for meibography image analysis. This method could serve as a valuable tool in facilitating more targeted investigations into MG characteristics.

Tear-film evaporation flux and its relationship to tear properties in symptomatic and asymptomatic soft-contact-lens wearers.

PURPOSE: With soft-contact-lens wear, evaporation of the pre-lens tear film affects the osmolarity of the post-lens tear film and this can introduce a hyperosmotic environment at the corneal epithelium, leading to discomfort. The purposes of the study are to ascertain whether there are differences in evaporation flux (i.e., the evaporation rate per unit area) between symptomatic and asymptomatic soft-contact-lens wearers, to assess the repeatability of a flow evaporimeter, and to assess the relationship between evaporation fluxes, tear properties, and environmental conditions. METHODS: Closed-chamber evaporimeters commonly used in ocular-surface research do not control relative humidity and airflow, and, therefore, misestimate the actual tear-evaporation flux. A recently developed flow evaporimeter overcomes these limitations and was used to measure accurate in-vivo tear-evaporation fluxes with and without soft-contact-lens wear for symptomatic and asymptomatic habitual contact-lens wearers. Concomitantly, lipid-layer thickness, ocular-surface-temperature decline rate (i.e., °C/s), non-invasive tear break-up time, tear-meniscus height, Schirmer tear test, and environmental conditions were measured in a 5 visit study. RESULTS: Twenty-one symptomatic and 21 asymptomatic soft-contact-lens wearers completed the study. A thicker lipid layer was associated with slower evaporation flux (p < 0.001); higher evaporation flux was associated with faster tear breakup irrespective of lens wear (p = 0.006). Higher evaporation flux was also associated with faster ocular-surface-temperature decline rate (p < 0.001). Symptomatic lens wearers exhibited higher evaporation flux than did asymptomatic lens wearers, however, the results did not reach statistical significance (p = 0.053). Evaporation flux with lens wear was higher than without lens wear but was also not statistically significant (p = 0.110). CONCLUSIONS: The repeatability of the Berkeley flow evaporimeter, associations between tear characteristics and evaporation flux, sample-size estimates, and near statistical significance in tear-evaporation flux between symptomatic and asymptomatic lens wearers all suggest that with sufficient sample sizes, the flow evaporimeter is a viable research tool to understand soft-contact-lens wear comfort.

Does ethnicity influence the short-term adaptation to first reading correction?

PURPOSE: Ethnic variations in accommodative amplitude (AA) are not uncommon. Accommodation can become reduced in response to short-term wear of first near spectacles. Whether ethnicity has an influence on the magnitude of this adaptation is not well understood. We investigated the impact of first near spectacles on changes in AA and on convergence cross-link interactions in incipient presbyopes of Chinese and Caucasian ethnicities. METHODS: Forty-one subjects (22 Caucasians and 19 Chinese) aged 36 to 44 years completed the study. Accommodative stimulus response function, AA, and AC/A and CA/C ratios were measured before and after single vision reading spectacles were used for near tasks over a 2-month period and then again 2 months after discontinuing near spectacle wear. RESULTS: After wearing reading spectacles for 2 months, the accommodative stimulus response slopes and AC/A and CA/C ratios remained invariant irrespective of ethnicity. The accommodative, but not vergence, bias decreased (p < 0.05). The nearpoint of accommodation shifted distally producing an average decrease in AA of 0.52 D from baseline (p < 0.05). Recovery to near baseline values occurred after discontinuing the reading glasses for 2 months. Differences based on ethnicity were not significant. The baseline AA vs. age plots showed steeper slopes for Chinese than the Caucasian subjects in the sample. CONCLUSIONS: The pattern of adaptation by accommodation and cross-link interactions to short-term first reading spectacles is not influenced by ethnicity.

Predicting demographics from meibography using deep learning.

This study introduces a deep learning approach to predicting demographic features from meibography images. A total of 689 meibography images with corresponding subject demographic data were used to develop a deep learning model for predicting gland morphology and demographics from images. The model achieved on average 77%, 76%, and 86% accuracies for predicting Meibomian gland morphological features, subject age, and ethnicity, respectively. The model was further analyzed to identify the most highly weighted gland morphological features used by the algorithm to predict demographic characteristics. The two most important gland morphological features for predicting age were the percent area of gland atrophy and the percentage of ghost glands. The two most important morphological features for predicting ethnicity were gland density and the percentage of ghost glands. The approach offers an alternative to traditional associative modeling to identify relationships between Meibomian gland morphological features and subject demographic characteristics. This deep learning methodology can currently predict demographic features from de-identified meibography images with better than 75% accuracy, a number which is highly likely to improve in future models using larger training datasets, which has significant implications for patient privacy in biomedical imaging.

Clinical assessment of a customized free-form progressive add lens spectacle.

PURPOSE: To determine whether there are significant differences in standard clinical measures of vision, progressive addition lens (PAL)-specific vision tests, or subjective ratings and preferences between customized free-form and standard non-free-form PALs in an experienced wearing population. In addition, we aim to determine whether subjective or objective clinical outcomes depend on demographic, PAL usage, spectacle prescription, or frame fitting characteristics. METHODS: In a randomized, double-masked cross-over trial, 95 experienced wearers wore Zeiss Individual customized free-form PAL spectacles (test) and standard non-free-form PAL spectacles (control) for 1 week each. At dispensing and after 1 week of wear, subjects were tested for distance and near visual acuity under both high and low contrast; in addition, 30° off-axis visual acuity was measured using a novel apparatus, as was the horizontal extent of clear, undistorted vision at reading distance. Subjects also completed a set of questionnaires detailing their satisfaction levels, adaptation times, and preferences for test or control spectacles for different visual tasks. RESULTS: The test spectacles were preferred overall and for distance, midrange, transitional and active vision, and rated higher in overall satisfaction (p = 0.006). There were no clinically important differences between test and control spectacles in standard clinical vision assessments. In the PAL-specific assessments, however, the horizontal extent of clear vision at reading distance was significantly greater with the test spectacles (p = 0.004). CONCLUSIONS: There were statistically significant preferences for the optically customized free-form lenses over the non-free-form lenses. Subjects also reported a wider field of undistorted vision when looking through the reading zone of the test spectacles. Although standard clinical vision assessments are not sufficiently refined to detect important objective differences between the spectacle types, customization taking into account back vertex distance, segment height, pantoscopic tilt, and wrap angle can result in a superior subjective wearing experience for many PAL patients.

The relationship of pre-corneal to pre-contact lens non-invasive tear breakup time.

PURPOSE: To examine the relationship between pre-corneal and pre-contact lens tear film stability (TFS), and to determine whether pre-corneal TFS is a reliable predictor of subsequent pre-lens TFS after a contact lens is placed on the eye. METHODS: 667 records met inclusion criteria and were extracted from a soft contact lens multi-study database. Multivariable linear mixed effects models were fit to examine the association between pre-corneal and pre-lens TFS, adjusting for potential confounders and accounting for repeated measures. Receiver Operating Characteristic (ROC) analysis was employed to assess the predictive performance of pre-corneal TFS for subsequent pre-lens TFS. TFS was quantified for this analysis as the non-invasive tear breakup time (NITBUT). RESULTS: Pre-corneal NITBUT was significantly related to the pre-lens NITBUT at both 10 min (p<0.001) and 2-6 hrs (p<0.001) post-lens insertion. However, the sensitivities of pre-corneal NITBUT for predicting symptom-associated thresholds of pre-lens NITBUT ranged from 50-65%, and specificities ranged from 57-72%, suggesting poor-to-moderate diagnostic performance. CONCLUSIONS: Despite the association of pre-corneal and pre-lens TFS, the inherent lability and sensitivity to environmental exposures of the tear film introduce significant variability into NITBUT measurements. Using pre-corneal NITBUT to identify likely successful contact lens candidates prior to fitting is thus not sufficiently accurate to be relied upon in the clinical setting.

Ocular surface cooling rate associated with tear film characteristics and the maximum interblink period.

The surface of the human eye is covered with a protective tear film that refreshes with each blink. Natural blinking occurs involuntarily, but one can also voluntarily blink or refrain from blinking. The maximum time one can refrain from blinking until the onset of discomfort is the maximum interblink period (MIBP). During the interblink period the tear film evaporates and thins from the ocular surface. Infrared thermography provides a non-invasive measure of the ocular surface temperature (OST). Due to evaporation, ocular surface cooling (OSC) generally occurs when the eyes are open and exposed to the environment. The purpose of our study was to investigate the effect of OSC rate on the MIBP, and to investigate the association of the MIBP with tear film characteristics in subjects who do and do not exhibit OSC. The MIBP was measured simultaneously with OST over time. Non-invasive tear breakup time, tear meniscus height, tear lipid layer thickness, and Schirmer I test strip wetted lengths were measured on a day prior to the thermography visit. Subjects were divided into cooling and non-cooling groups based on OSC rate, and demographic and tear film characteristics were tested for inter-group differences. A faster OSC rate was associated with an exponentially shorter duration of the MIBP overall and within the cooling group alone. Faster non-invasive tear breakup time was significantly associated with a shorter MIBP in both groups. These results suggest that tear film evaporation initiates a pathway that results in the onset of ocular discomfort and the stimulus to blinking. The presence of a subset of subjects with no or minimal OSC who nevertheless have a short MIBP indicates that evaporative cooling is not the only mechanism responsible for the onset of ocular discomfort.

Conjunctival epithelial flap in continuous contact lens wear.

PURPOSE: Composed of sheets of cells detached from the underlying conjunctiva, conjunctival epithelial flap (CEF) is a recently reported phenomenon associated with contact lens wear with potential consequences for ocular health. Although CEF is generally asymptomatic, it is not known to what extent it might increase the longer-term risk of discomfort, inflammatory response, or infection. In this study, we use survival analysis methods to obtain unbiased estimates of the probability of developing CEF, the mean survival time free of CEF, and the effects of age, gender, ethnicity, and contact lens type. METHODS: Two hundred four subjects were recruited for a continuous wear (CW) study of silicone hydrogel (SiH) and gas permeable (GP) contact lenses. Subjects were examined by optometrists throughout contact lens adaptation and CW periods. Statistical methods included the Kaplan-Meier nonparametric estimator of the survival function and the Cox proportional hazards model for estimating the relative effects of covariates. RESULTS: Of the 204 subjects, 72 (35%) developed CEF. In 64% of cases, CEFs were observed bilaterally. The majority of cases (90.3%) presented with CEF in the superior conjunctiva. Mean survival time free of CEF was longer for GP lenses (94.3 days) than for SiH lenses (76.5 days), and the probability of developing CEF was significantly greater for SiH lenses (p = 0.002). Although there was some evidence that women and non-Asians remain free of CEF longer, the effects of age, gender, and ethnicity were not statistically significant. CONCLUSIONS: There was a significantly increased risk of CEF in subjects wearing SiH lenses, compared with GP lenses. Subjects wearing SiH lenses remained free of CEF for a shorter time on average. Further study is needed to determine whether the increased incidence of CEF in CW with SiH lenses poses an increased risk of adverse ocular response or infection.

Human Lacrimal Production Rate and Wetted Length of Modified Schirmer's Tear Test Strips.

PURPOSE: To assess and compare the wetting kinetics of sheathed and unsheathed Schirmer's tear test (STT) strips, and to determine the repeatability of 5-minute wetted length (WL) and basal tear production rate (BTPR). METHODS: Seventeen subjects underwent two sheathed and unsheathed STTs each for both eyes on four visits on separate days. After administration of topical anesthetic, WLs were measured every 30 seconds for 5 minutes, and BTPRs were calculated for sheathed strips. Limits of agreement (LoA), difference-versus-mean plots (DVM), and the coefficient of repeatability (CR) assessed WL and BTPR repeatabilities. Variance estimates were used to calculate sample sizes for future study. RESULTS: For the unsheathed STT, the mean (SD) difference in WLs between visits was 0.74 (5.05) mm, LoA were [-9.17, 10.64], and CR was 9.17 mm; for the sheathed STT, the mean (SD) intervisit difference was 0.16 (5.94) mm, LoA were [-11.49, 11.8], and CR was 10.53 mm. Eight of 48 sheathed STTs and 20 of 44 unsheathed STTs showed constant WL for the final 90 seconds of the test. The mean (SD) difference between repeated visits for BTPR was approximately 0.0 µL/min, LoA were [-1.82, 1.82], and CR was 1.91 µL/min. CONCLUSIONS: Repeatability of sheathed and unsheathed 5-minute WL and BTPR is inadequate for measuring within-subject changes, but is sufficient for group studies with moderate sample sizes. Constant WL for the final 90 seconds with the eight sheathed STT measurements suggests varying BTPR, whereas constant WL with the unsheathed STT can be explained by balancing evaporation and BTPR. TRANSLATIONAL RELEVANCE: Repeatability of the modified STT is evaluated clinically to establish quantitative BTPRs rather than inference from a strip WL.

The Berkeley Dry Eye Flow Chart: A fast, functional screening instrument for contact lens-induced dryness.

PURPOSE: In this article, we introduce a novel flow chart-based screening tool for the categorization of contact lens-induced dryness (CLIDE) and its impact on daily visual activities: the Berkeley Dry Eye Flow Chart (DEFC). METHODS: One hundred thirty (130) experienced soft contact lens wearers discontinued lens wear for 24 hrs, passed a baseline screening and eye health examination, completed the Ocular Surface Disease Index (OSDI) then were dispensed fresh pairs of their habitual lenses. After 6 hrs of wear, subjects were administered a battery of symptom questionnaires, and underwent non-invasive tear breakup time (NITBUT) measurement, grading of distortion in reflected topographer mires, grading of lens surface wettability, and a fluorescein examination of the ocular surface. Subjects returned after at least 48 hrs and repeated all assessments after 6 hrs of wear of a second fresh pair of habitual lenses. RESULTS: The repeatability of the DEFC between visits was within 1%, and Limits of Agreement and Coefficient of Repeatability were comparable to those of the other CLIDE assessments. Higher DEFC score was significantly related to shorter pre-lens NITBUT, higher OSDI score, and higher Visual Analog Scale (VAS) ratings of average and end-of-day severity and frequency of dryness (all p < 0.001). For CLIDE as diagnosed based on DEFC score, the highest sensitivities and specificities were achieved by the OSDI and VAS ratings; pre-lens NITBUT exhibited good sensitivity but poor specificity. The optimum pre-lens NITBUT diagnostic threshold was found to be ≤ 2.0 sec for debilitating CLIDE, and the OSDI threshold was ≥ 11.4. CONCLUSIONS: The DEFC provides a means of quickly categorizing CLIDE patients based on severity and frequency of symptoms, and on the degree to which symptoms impact daily life. The DEFC has several potential advantages as a CLIDE screening and monitoring tool, has good repeatability, and is significantly related to commonly employed clinical assessments for CLIDE.

Effects of corneoscleral topography on soft contact lens performance: A pilot study.

To quantify corneoscleral junction (CSJ) topography in soft contact lens (SCL) wearers, and assess the association between the CSJ and SCL performance and subjective comfort, forty-four adapted SCL wearers (16 Asians, 16 Caucasians, 12 Latinos) were recruited for the present study. Corneal topography was taken with a Medmont E300 (Medmont International, Pty Ltd.). CSJ images were taken with a commercial OCT (Bioptigen, Inc.). Our published CSJ image analysis technique was used to describe the geometric properties of the CSJ using the sum of squared orthogonalized residuals (SSRo). Multivariable mixed effects models were employed to examine associations between SSRo and subject demographics, ocular characteristics, SCL fit and performance, and comfort. The SSRo was significantly related to quadrant (p < 0.001), ethnicity (p = 0.014), and horizontal corneal shape factor (p = 0.044). The nasal quadrant had the largest SSRo, indicating the steepest CSJ profile and/or the most irregular CSJ surface, followed by the inferior quadrant. The superior and temporal quadrants had the smallest SSRo, indicating relatively flat and even CSJ topography. Caucasians had the steepest and/or most irregular CSJ compared with Latinos and Asians. Less inferior-superior heterogeneity in the SSRo was associated with greater comfort after 6 h of lens wear. The SSRo was proved to be a useful tool to quantify CSJ geometry in SCL wearers. Significant differences in the SSRo were found among quadrants and ethnic groups. Better subjective comfort after 6 h of SCL wear was associated with a smaller difference in the SSRo between the superior and inferior quadrants.

Understanding Ocular Discomfort and Dryness Using the Pain Sensitivity Questionnaire.

PURPOSE: To utilize the Pain Sensitivity Questionnaire (PSQ) to assess the influence of pain sensitivity on perceptions of ocular discomfort and dryness. METHODS: Subjects completed a battery of questionnaires, including history of ocular and general health, contact lens wear history, the Ocular Surface Disease Index (OSDI) questionnaire, visual analog scale (VAS) 100-point rating scales to assess severity and frequency of average and end of day (EOD) discomfort and dryness, and the PSQ to assess pain sensitivity level. Masked subjects were then instructed to wear one inverted and one normally oriented soft contact lens contralaterally for 30 minutes to induce an inter-eye difference in comfort and dryness sensations. Subjects rated comfort and dryness in each eye on VAS every 5 minutes during contact lens wear. A slit lamp examination was performed to evaluate ocular surface health and to assess contact lens fit. RESULTS: One hundred and fifty-three subjects (111 females, 42 males) completed the study. In separate models, a higher PSQ score was significantly associated with higher OSDI score (p = 0.002), lower average and EOD comfort (p = 0.005 and 0.001, respectively), and greater EOD dryness (p = 0.04). The minimum (0.14) and maximum (7.14) PSQ scores observed in our subject cohort (i.e., from the subjects who were the least and most sensitive to pain, respectively) corresponded to an estimated difference of 11 points on the OSDI, 20 points on the VAS scale for average comfort, 31 points for EOD comfort and 17 points for EOD dryness. In a mixed effects model, a higher PSQ score was significantly associated with a greater inter-eye difference in comfort (p = 0.013) and dryness (p = 0.010) during CL wear. CONCLUSIONS: Pain sensitivity influences perceptions of ocular discomfort and dryness, and should be taken into account when evaluating subjective assessments of these symptoms.

Impact of rigid gas-permeable contact lens extended wear on corneal epithelial barrier function.

PURPOSE: To measure the effect of hypoxia and eye closure on epithelial permeability to fluorescein (P(dc)) during rigid lens extended wear (EW). METHODS: Central corneal thickness (CT) and P(dc) were measured in 42 subjects with an optical pachometer and automated scanning fluorophotometer, respectively. All subjects had been successfully wearing rigid gas-permeable (RGP) lenses on a 6-night EW regimen, and each individual was randomized to wear either medium- or high-oxygen-permeable (Dk) RGP lenses (two types of siloxane-fluorocarbon polymer lenses with Dk of 49 and 92). CT and P(dc) measurements were performed at an afternoon visit (baseline) and were repeated in the morning after 8 hours of overnight wear. Subjects slept with a patch over the right eye. The patch was not removed until immediately before the morning measurement. RESULTS: The mean overnight swelling response for subjects in the medium-Dk group was greater than that in the high-Dk group. Results of a paired t-test indicate that the eye wearing the medium-Dk lens with a patch overnight had a significant increase in epithelial permeability. Results of mixed-effect models suggest that eye closure and lens-induced hypoxia are significant factors in altering P(dc). CONCLUSIONS: The results indicate that corneal epithelial permeability increases with hypoxic dose and that epithelial barrier function is impaired by overnight rigid lens wear.