Subjective Comfort and Physiology with Modern Contact Lens Care Products.

PURPOSE: To compare subjective comfort and ocular physiology with three multipurpose solutions (MPSs) to that of a peroxide-based system with three different soft contact lens materials. METHODS: Habitual soft contact lens wearers (n = 236) were enrolled at three sites and completed a washout period with no contact lens solution for ≥4 days. Subjects were randomly assigned to one of three lens types: etafilcon A, galyfilcon A, or senofilcon A. A new lens of the assigned type was worn for 10 to 14 days each while using one of four care solutions, in random order (A-polyaminopropyl biguanide + polyquaternium, B-POLYQUAD + Aldox, C-alexidine + polyquaternium-1, and D-hydrogen peroxide) with a washout period (≥4 days) between each solution. After each care solution, biomicroscopy was performed and subjective comfort was assessed using the Contact Lens User Experience (CLUE) questionnaire and other instruments including comfortable wear time (CWT). Linear mixed models were used for analysis. Comfort and biomicroscopy signs with each MPS were compared to that of the peroxide solution. RESULTS: Subjective CLUE Comfort score across all lens types with each MPS was not significantly different than with the peroxide solution (p = 0.98). There were no differences in CWT between each MPS and the peroxide solution for any lens type (range of differences: -0.8 to 0.8 h; all p ≥ 0.13). Six MPS/material combinations had no clinically meaningful change in corneal staining versus peroxide (<0.5 units); three combinations could increase staining by up to 0.57 units. Staining was

Clinical performance of three silicone hydrogel daily disposable lenses.

PURPOSE: To determine the clinical performance of DAILIES TOTAL1 (DT1), Clariti 1Day (C1D), and 1-DAY ACUVUE TruEye (AVTE) silicone hydrogel daily disposable contact lenses (SiHy DDCLs). METHODS: Eligible participants, subdivided into asymptomatic and symptomatic groups, wore each SiHy DDCLs for three consecutive days. Each participant attended three visits (on day 1 at 0 hours; on days 1 and 3 after 8 hours of wear) per lens type. The order of lens wear was randomized, with at least 1 day washout between lenses. Lens-related performance was evaluated by assessing lens surface deposits, wettability, pre-lens noninvasive tear breakup time, lens movement, and centration; ocular response assessments included conjunctival redness, corneal staining, and conjunctival staining and indentation. RESULTS: Fifty-one asymptomatic and 53 symptomatic participants completed the study. For all visits, the mean noninvasive tear breakup time was about 1 second longer with DT1 than with C1D and AVTE (p < 0.01). Overall, the wettability of all three lenses was good; however, DT1 was graded marginally better than the other lenses (both p < 0.01). On day 3, eyes wearing AVTE had significantly more dehydration-induced corneal staining compared with DT1 (AVTE, 24%; DT1, 11%; p < 0.01). After 8 hours, conjunctival staining was different between lenses (greatest with C1D and least with DT1; all p < 0.01). Conjunctival indentation was more prevalent with the C1D lenses (n = 70) compared with DT1 (n = 1; p < 0.01) and AVTE (n = 11; p < 0.01). There were no differences between asymptomatic and symptomatic lens wearers for any of the clinical parameters (all p > 0.05). CONCLUSIONS: Each of the three SiHy DDCLs performed well. Noninvasive tear breakup time was longest and wettability was greater with DT1. C1D had the most conjunctival staining conjunctival indentation. There was no difference between asymptomatic and symptomatic wearers with regard to ocular response and contact lens-related parameters. These results suggest that SiHy DDCLs may be an excellent contact lens modality for the symptomatic patient.

Grading bulbar redness using cross-calibrated clinical grading scales.

PURPOSE: To determine the between-scale agreement of grading estimates obtained with cross-calibrated McMonnies/Chapman-Davies (MC-D), Institute for Eye Research (IER), Efron, and Validated Bulbar Redness (VBR) grading scales. METHODS: Modified reference images of each grading scale were positioned on a desk according to their perceived redness (within a 0 to 100 range) as determined in a previous psychophysical scaling experiment. Ten observers were asked to represent perceived bulbar redness of 16 sample images by placing them, one at a time, relative to the reference images of each scale. Only 0 and 100 were marked on the scale, but not the numerical position of the reference images. Perceived redness was taken as the measured position of the placed image from 0 and was averaged across observers. RESULTS: Overall, perceived redness depended on the sample image and the reference scale used (repeated measures ANOVA; P = 0.0008); six sample images had a perceived redness that was significantly different between at least two of the scales. Between-scale correlation coefficients of concordance ranged from 0.93 (IER vs. Efron) to 0.98 (VBR vs. Efron). Between-scale coefficients of repeatability ranged from five units (IER vs. VBR) to eight units (IER vs. Efron) of the 0 to 100 range. CONCLUSIONS: The use of cross-calibrated reference grades for bulbar redness grading scales allows comparison of grading estimates obtained with different scales. Perceived redness is dependent on the dynamic range of the reference images of the scale, with redness estimates generally being found to be higher for scales with a shorter dynamic range.

The conversion of bulbar redness grades using psychophysical scaling.

PURPOSE: To use psychophysical scaling to investigate if the inclusion of reference anchors affected the perceived redness of the reference images of four bulbar redness grading scales and to convert grades between scales. METHODS: Ten participants were asked to arrange printed copies of the McMonnies/Chapman-Davies (6), IER (4), and Efron (5) grading scale images relative to each other, using the stationary but unlabeled 10, 30, 50, 70, and 90 reference images of the validated bulbar redness scale as additional anchors within a given 0 (minimum) to 100 (maximum) redness range (anchored scaling). The position of each image was averaged across observers to represent its perceived redness within this range. Anchored scaling data were then compared with data from a previous study, where the images of all four grading scales had been scaled for the same experimental setup, but with no reference anchors provided (non-anchored scaling). Averaged perceived redness as determined with anchored scaling was used to cross-calibrate grades between scales. RESULTS: Overall, perceived redness of the reference images was significantly different within each scale (repeated measures analysis of variance, all scales p < 0.001). There were differences in perceived redness range and when comparing reference levels between scales. Anchored scaling resulted in an apparent shift to lower perceived redness for all but one reference image compared with non-anchored scaling, with the rank order of the 20 images for both procedures remaining fairly constant (Spearman's ρ = 0.99). CONCLUSIONS: The re-scaling of the reference images in the anchored scaling experiment suggests that redness was assessed based on within-scale characteristics and not using absolute redness scores, a mechanism that can be referred to as clinical scale constancy. The perceived redness data allow practitioners to modify the grades of the scale they commonly use for comparison of their grading estimates with grades obtained with another calibrated scale.

The perceived bulbar redness of clinical grading scales.

PURPOSE: To use a psychophysical scaling method to estimate the perceived redness of reference images of the McMonnies and Chapman-Davies (six reference levels), Institute for Eye Research (four), Efron (five), and Validated Bulbar Redness (five) bulbar redness grading scales. METHODS: Regions of interest were cropped out of the grading scale reference images; three separate image sets (color, grayscale, and binarized) were created for each scale, combining to a total of 20 images per image set. Ten naïve observers were asked to arrange printed copies of the 20 images per image set across a distance of 1.5 m on a flat surface, so that separation reflected their perception of bulbar redness; only start and end point of this range were indicated. The position of each image was averaged across observers to represent the perceived redness for this image, within the 0 to 100 range. Subjective data were compared with physical attributes (chromaticity and spatial metrics) of redness. RESULTS: For each image set, perceived redness of the reference images within each scale was ordered as expected, but not all consecutive within-scale levels were rated as having different redness. Perceived redness of the reference images varied between scales, with different ranges of severity being covered by the images. Perception of redness severity depended on the image set (repeated-measures analysis of variance; all p < or = 0.0002). The perceived redness was strongly associated with the physical attributes of the reference images. CONCLUSIONS: Subjective estimates of redness are based on a combination of chromaticity and vessel-based components. Psychophysical scaling of perceived redness lends itself to being used to cross-calibrate these four clinical scales.

The use of fractal analysis and photometry to estimate the accuracy of bulbar redness grading scales.

PURPOSE: To use physical attributes of redness to determine the accuracy of four bulbar redness grading scales, and to cross-calibrate the scales based on these physical measures. METHODS: Two image-processing metrics, fractal dimension (D) and percentage of pixel coverage (% PC), as well as photometric chromaticity were selected as physical measures, to describe and compare grades of bulbar redness among the McMonnies/Chapman-Davies scale, the Efron Scale, the Institute for Eye Research scale, and a validated scale developed at the Centre for Contact Lens Research. Two sets of images were prepared by using image processing: The first included multiple segments covering the largest possible region of interest (ROI) within the bulbar conjunctiva in the original images; the second contained modified scale images that were matched in size and resolution across scales, and a single, equally-sized ROI. To measure photometric chromaticity, the original scale images were displayed on a computer monitor, and multiple conjunctival segments were analyzed. Pearson correlation coefficients between each set of image metrics and the reference image grades were calculated to determine the accuracy of the scales. RESULTS: Correlations were high between reference image grades and all sets of objective metrics (all Pearson's r >or= 0.88, P

The development of validated bulbar redness grading scales.

PURPOSE: To develop a perceptually and physically based bulbar redness grading scale. METHODS: Digital conjunctival hyperemia photographs were taken using a photo-slit lamp at controlled exposures. Nine participants arranged 25 images on a tabletop over a range of 1.5 m, using separation to represent changes in redness. The position of each image was recorded and normalized for a 0 to 100 scale, and compared to chromaticity of each image obtained using a spectrophotometer. The performance of two versions of the scale (5 and 10 images) and a continuous grading scale was evaluated based on repeatability data collected from nineteen observers who used each scale twice to grade 30 randomly presented images of bulbar redness. RESULTS: Psychophysical scaling was highly correlated between single observers (Pearson's r >or= 0.92, p < 0.05). The averaged subjective grades significantly correlated with chromaticity (r = 0.95 and r = 0.99, p < 0.001 for CIE u* and log u*, respectively). Across all observers, test and retest ratings were highly correlated with either scale (r >or= 0.98), and showed high levels of repeatability expressed by intraclass correlation coefficients (ICC >or= 0.98), correlation coefficients of concordance (CCC >or= 0.96), and coefficients of repeatability (COR