Kathryn Richdale

Frequency of and factors associated with contact lens dissatisfaction and discontinuation.

Purpose: To determine the frequency of and factors associated with contact lens dissatisfaction and discontinuation. Methods: A cross-sectional survey of 730 subjects was conducted using a self-administered survey instrument. The survey collected information about present age and sex, history of contact lens wear, types of lenses worn, age at starting wear, current wearing schedule (hours per day, days per week), self-perceived contact lens satisfaction, and contact lens-related problems. A variety of statistical analyses including analysis of variance, logistic regression, and repeated-measures logistic regression were used to model the data. Results: Current or previous experience with contact lenses was reported by 453 (62%) of the subjects. Of these subjects, 119 (26.3%) reported that contact lenses were not the ideal form of visual correction for them (contact lens dissatisfaction) and another 109 (24.1%) had permanently discontinued contact lens wear. Dissatisfied contact lens wearers had reduced self-reported wearing times compared with satisfied contact lens wearers. Previous lens wearers were more likely than current lens wearers to be men, older (by ∼9.5 years), have started contact lens wear at a later age (∼4-5 years later), and have tried either rigid or both soft and rigid lenses. The primary self-reported reason for both contact lens dissatisfaction and discontinuation was ocular symptoms (dryness and discomfort), followed by preference for another corrective modality. Conclusion: A significant number of contact lens wearers are not satisfied with contact lenses and are at risk for discontinuation.

Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia

Purpose. The purpose of this study was to assess visual performance and patient satisfaction with two presbyopic soft contact lens modalities. Methods. A crossover study of 38 patients with presbyopia was conducted. Patients were randomized first into either multifocal (Bausch & Lomb SofLens Multifocal) or monovision (SofLens 59) for 1 month. Visual performance was measured with high- and low-contrast visual acuity at distance and near and near stereoacuity. Patients’ satisfaction was measured by the National Eye Institute Refractive Error Quality of Life Instrument questionnaire and by recording the patient’s final lens preference. Results. Patients maintained at least 20/20 binocular vision with both multifocal (MF) and monovision (MV) contact lenses under high-contrast conditions at distance and near. Under low-contrast conditions, patients lost less than a line of vision from the best spectacle correction to either multifocal or monovision contact lens correction at distance (pMF = 0.001, pMV = 0.006). Under low-contrast conditions at near, multifocal wearers lost five to six letters and monovision wearers lost two letters of vision (pMF < 0.001, pMV = 0.03, pMF/MV = 0.005). The average stereoacuity decreased by 79 s arc with monovision vs. multifocal contact lenses (p = 0.002). On the NEI-RQL, patients reported worse clarity of vision (pMF = 0.01, pMV < 0.001), more symptoms (pMF = 0.09, pMV = 0.01), and an improvement in their appearance with contact lens wear (pMF < 0.001, pMV < 0.001). Seventy-six percent of patients reported that they preferred multifocal contact lenses, and 24% preferred monovision contact lenses (p = 0.001). Conclusion. The majority of our patients preferred multifocals to monovision, most likely because the Bausch & Lomb SofLens Multifocal provides excellent visual acuity without compromising stereoacuity to the same degree as monovision.

Age and Other Risk Factors for Corneal Infiltrative and Inflammatory Events in Young Soft Contact Lens Wearers from the Contact Lens Assessment in Youth (CLAY) Study

PURPOSE To describe age and other risk factors for corneal infiltrative and inflammatory events (CIEs) in young, soft contact lens (SCL) wearers and to model the age-related risk. METHODS A multicenter, retrospective chart review of 3549 SCL wearers (8-33 years at first observed visit, +8.00 to -12.00D, oversampling <18 years) captured CIEs from January 2006 to September 2009. The review noted age, sex, SCL worn, use of lens care products, and SCL wearing history. Event diagnoses were adjudicated to consensus by reviewers masked to wearer identity, age, and SCL parameters. Significant univariate risk factors for CIEs were subsequently tested in multivariate generalized estimating equations. RESULTS Charts from 14,305 visits observing 4,663 SCL years yielded 187 CIEs in 168 wearers. Age was a significant nonlinear risk factor, peaking between 15 and 25 years (P < 0.008). Less than 1 year of SCL use was protective versus longer years of wear (P < 0.0003). Use of multipurpose care products (2.86×), silicone hydrogels (1.85×), and extended wear (2.37×) were significantly associated with CIEs in the multivariate model (P < 0.0001 each). CONCLUSIONS Patient age, years of lens wear, use of multipurpose care products, silicone hydrogels, and extended wear were all significantly associated with CIEs with SCL wear. Use of SCLs in young patients aged 8 to 15 years was associated with a lower risk of infiltrative events compared with teens and young adults. In terms of safety outcomes, SCLs appear to be an acceptable method of delivering optics designed to manage myopia progression in children and young teens in the future.

Lens thickness with age and accommodation by optical coherence tomography.

Purpose:  To utilize time‐domain optical coherence tomography (OCT) to measure changes in the crystalline lens with age and accommodation.

Quantification of age-related and per diopter accommodative changes of the lens and ciliary muscle in the emmetropic human eye.

PURPOSE To calculate age-related and per diopter (D) accommodative changes in crystalline lens and ciliary muscle dimensions in vivo in a single cohort of emmetropic human adults ages 30 to 50 years. METHODS The right eyes of 26 emmetropic adults were examined using ultrasonography, phakometry, anterior segment optical coherence tomography, and high resolution magnetic resonance imaging. Accommodation was measured both subjectively and objectively. RESULTS In agreement with previous research, older age was linearly correlated with a thicker lens, steeper anterior lens curvature, shallower anterior chamber, and lower lens equivalent refractive index (all P < 0.01). Age was not related to ciliary muscle ring diameter (CMRD) or lens equatorial diameter (LED). With accommodation, lens thickness increased (+0.064 mm/D, P < 0.001), LED decreased (-0.075 mm/D, P < 0.001), CMRD decreased (-0.105 mm/D, P < 0.001), and the ciliary muscle thickened anteriorly (+0.013 to +0.026 mm/D, P < 0.001) and thinned posteriorly (-0.011 to -0.015, P < 0.01). The changes per diopter of accommodation in LED, CMRD, and ciliary muscle thickness were not related to subject age. CONCLUSIONS The per diopter ciliary muscle contraction is age independent, even as total accommodative amplitude declines. Quantifying normal biometric dimensions of the accommodative structures and changes with age and accommodative effort will further the development of new IOLs designed to harness ciliary muscle forces.

7 Tesla MR imaging of the human eye in vivo

To develop a protocol which optimizes contrast, resolution and scan time for three‐dimensional (3D) imaging of the human eye in vivo using a 7 Tesla (T) scanner and custom radio frequency (RF) coil.

Measuring Changes in Ciliary Muscle Thickness with Accommodation in Young Adults

Purpose. To develop a measurement protocol for changes in the shape and size of the ciliary muscle with accommodation using the Zeiss Visante™ anterior segment optical coherence tomography (AS-OCT) and to determine the test-retest repeatability of these measurements. Methods. Subjects were 25 adults aged 23 to 28 years. The ciliary muscle was imaged at two visits with the Visante™ while accommodative response was monitored during imaging using the PowerRefractor. Ciliary muscle thickness (CMT) was measured at 1 mm (CMT1), 2 mm (CMT2), and 3 mm (CMT3) posterior to the scleral spur and at the point of maximal thickness (CMTMAX). Thickness was measured at these locations while subjects viewed a target at distance and at a 4.00 D accommodative stimulus. Outcome measures were the change in thickness between distance and the 4.00 D stimulus and the change in thickness per diopter of accommodative response (PowerRefractor). Finally, the repeatability measurements between visit 1 and visit 2 were determined with a Bland-Altman analysis. Results. The statistically significant modeled changes in CMT were as follows: CMTMAX = 69.2 &mgr;m (4.00 D stimulus) and 18.1 &mgr;m (per diopter of accommodation); CMT1 = 45.2 &mgr;m (4.00 D stimulus) and 12.3 &mgr;m (per diopter of accommodation); and CMT3 = −45.9 &mgr;m (4.00 D stimulus) and −12.0 &mgr;m (per diopter of accommodation); p < 0.0001 for all. Conclusions. The combination of the Visante™ and the PowerRefractor is a feasible tool for measuring thickening of ciliary muscle at more anterior locations and thinning at more posterior locations during accommodation. We noted a wide range of accommodative responses during the time of image capture in this study indicating that the most accurate estimates of the change in ciliary muscle dimensions with accommodation may be obtained by using accommodative response rather than stimulus values and by using measurements taken simultaneously with image capture.

Risk factors for interruption to soft contact lens wear in children and young adults.

Purpose. The purpose of this study was to describe age and other risk factors for ocular events that interrupt soft contact lens (SCL) wear in youth. Methods. A retrospective chart review of SCL wearers aged 8 to 33 years at the first observed visit was conducted at six academic eye care centers in North America. Data were extracted from all visits during the observation period (>3 years). Clinical records that documented conditions resulting in an interruption of SCL wear “events” were scanned, masked for age and SCL parameters, and then adjudicated to consensus diagnosis. Generalized estimating equations were used to examine the effect of selected covariates, including age, on the risk of an event. Results. Chart review of 3549 SCL wearers yielded 522 events among 426 wearers (12%). The risk of an event increased from ages 8 to 18 years, showed modest increases between ages 19 and 25 years, and then began to decline after age 25 years. New lens wearers (<1 year) were less likely to experience events (p = 0.001). Lens replacement schedule and material were also predictive of interruptions to SCL wear with the lowest risk in daily replacement and hydrogel lens wearers (both p < 0.0001). Conclusions. These results suggest that the risk of events that interrupt SCL wear peaks in late adolescence and early adulthood and reflects risk factors identified in prospective contact lens studies. Relative to older teens and young adults, patients younger than 14 years presented with significantly fewer events resulting in interrupted lens wear.

Visual acuity with spherical and toric soft contact lenses in low- to moderate-astigmatic eyes.

Purpose. To evaluate the visual acuity of myopic, astigmatic eyes, with spherical and toric soft contact lenses. Methods. A randomized, masked, cross-over study was conducted to compare acuity with soft spherical and toric contact lenses on patients with between −0.75 and −2.00 D of refractive astigmatism. A total of 15 patients (30 eyes) were fitted with four brands of spherical and toric lenses (Acuvue Advance, Biomedics 55, Frequency 55, and SofLens 66), in random order. An initial visit was conducted to fit the lenses and an over-refraction (OR) was performed to determine the best prescription. At the measurement visit, patients’ pupils were dilated with 1.0% tropicamide and 2.5% phenylephrine to allow wavefront aberration measurements, and a final OR was performed. A 6-mm aperture was held in front of the eye to measure visual acuity through just the contact lens and the contact lens with the final OR. Acuity was measured monocularly, under photopic and mesopic conditions with high- and low-contrast logMAR charts at distance. Differences in acuity were analyzed using repeated measures analysis of variance. Results. Visual acuity with soft spherical contact lenses was not significantly different between lens brands. For toric contact lenses, acuity was significantly better with Biomedics 55 and SofLens 66 than with Acuvue Advance; and acuity with SofLens 66 was significantly better than with Frequency 55. Low-astigmatic eyes gained between 3 and 5.5 letters of acuity with toric contact lenses vs. spherical lenses; and moderate-astigmatic eyes gained between 8 and 12.5 letters. Conclusions. Both low- and moderate-astigmatic eyes showed improvements in acuity with toric contact lenses. Lens brand had a measurable effect on acuity for toric contact lenses. Further investigation of aberrations induced by contact lens design is warranted to explain the observed differences in visual performance.

The Effect of Phenylephrine on the Ciliary Muscle and Accommodation

Purpose. To objectively measure changes in the human ciliary muscle dimensions in vivo after instillation of topical phenylephrine, a mydriatic and vasodilating agent. Methods. A cross-sectional study of 25 healthy young adults was conducted. Measurements of pupil size, accommodation, and ciliary muscle thickness were made both before and 30 min after instillation of 1% proparacaine and 2.5% phenylephrine. Accommodation was measured in three ways: subjectively using a push-up technique and Royal Air Force (RAF) rule, and objectively using both the Grand Seiko autorefractor and PowerRefractor. Images of the temporal ciliary muscle were acquired using the Visante Anterior Segment Optical Coherence Tomographer (OCT). Ciliary muscle images were objectively analyzed using a computer-based segmentation technique. Results. Amplitude of accommodation using the push-up test was reduced by about 1 D with phenylephrine (p < 0.001). Phenylephrine did not change the accommodative response to a 4 D Badal target as measured by either autorefraction or photorefraction (p > 0.30). There was statistically significant thickening of the anterior region and thinning of the posterior region of the ciliary muscle with accommodation (p < 0.001, all locations). Phenylephrine did not affect either baseline ciliary muscle thickness or the accommodative contraction of the muscle (p > 0.09). Conclusions. Low-dose phenylephrine does not affect ciliary muscle dimensions, ciliary muscle contractility, or accommodative response to a 4 D near target.