Browsing by Author "Berntsen, David A."
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Item A Randomized Trial Using Progressive Addition Lenses to Evaluate Theories of Myopia Progression in Children with a High Lag of Accommodation(Investigative Ophthalmology & Visual Science, 2012-02) Berntsen, David A.; Sinnott, Loraine T.; Mutti, Donald O.; Zadnik, KarlaPURPOSE: To compare the effect of wearing, then ceasing to wear, progressive addition lenses (PALs) versus single vision lenses (SVLs) on myopia progression in children with high accommodative lag to evaluate accommodative lag and mechanical tension as theories of myopia progression. METHODS: Eighty-five children (age range, 6-11 years) with spherical equivalent (SE) cycloplegic autorefraction between -0.75 D and -4.50 D were randomly assigned to wear SVLs or PALs for 1 year; all children wore SVLs a second year. Children had high accommodative lag and also had near esophoria if their myopia was greater than -2.25 D SE. The primary outcome after each year was the previous year's change in SE. RESULTS: When the children were randomly assigned to SVLs or PALs, the adjusted 1-year changes in SE were -0.52 D (SVL group) and -0.35 D (PAL group; treatment effect = 0.18 D; P = 0.01). When all children wore SVLs the second year, there was no difference in myopia progression between SVL and former PAL wearers (0.06 D; P = 0.50). Accommodative lag was not associated with myopia progression. CONCLUSIONS: The statistically significant, but clinically small, PAL effect suggests that treatments aimed at reducing foveal defocus may not be as effective as previously thought in myopic children with high accommodative lag. Finding no evidence of treatment loss after discontinuing PAL wear supports hyperopic defocus-based theories such as accommodative lag; however, not finding an association between accommodative lag and myopia progression is inconsistent with the PAL effect being due to decreased foveal blur during near work. (Clinical Trials.gov number, NCT00335049.).Item Comparison of Toric Orthokeratology and Soft Toric Multifocal Contact Lenses in Managing the Astigmatic Myope(2022-05-11) Tomiyama, Erin S.; Richdale, Kathryn L.; Berntsen, David A.; Marsack, Jason D.; Zadnik, KarlaPurpose: Myopia management is an important intervention to reduce the risk of vision threatening ocular disease. Contact lens treatments for patients with astigmatism include toric orthokeratology (TOK) and soft toric multifocal (STM) lenses. The purpose of this study was to quantify visual performance and the potential for myopia management efficacy with TOK and STM in moderate to high astigmatic patients. Methods: Thirty adults, age 18-39 years, with myopia (plano to -5.00 D) and refractive astigmatism (-1.25 to -3.50 D) were recruited to complete this five-visit crossover study. Subjects wore both TOK and STM lenses in random order for 10±2 days each. After lens wear, visual performance and acceptance was measured with logMAR visual acuity and patient-reported outcome surveys. Peripheral refraction and wavefront aberrometry were measured to determine the lens’ potential impact for myopia management. Results: Adults, who are critical users, preferred STM for cost when forced to choose between the two corrections. Compared to baseline, TOK induced a myopic shift in defocus (M) at all retinal locations except 20 degrees nasal (all p<0.03), but STM only induced a myopic shift at 20 degrees temporal (p<0.03). TOK resulted in more myopic defocus than STM at all locations (all p<0.05) except 20 degrees nasal and temporal in the left eye. Higher-order root mean square wavefront error (5 mm pupil diameter) was significantly increased with TOK (0.64±0.22 µm) and STM (0.48±0.11 µm) from baseline (0.24±0.08 µm, both p < 0.001), and TOK was elevated compared to STM (p = 0.026). Conclusion: TOK induced greater peripheral myopic defocus and higher-order aberrations, which may indicate improved efficacy for myopia management. Adult astigmats preferred the vision with TOK over STM.Item Effects of Defocus on Choroidal Thickness in Children and Adults(2021-05) Tran, Raphaella Hoang; Ostrin, Lisa A.; Berntsen, David A.; Patel, Nimesh B.Purpose: The choroid responds to short exposures of defocus in a bidirectional manner, demonstrating thickening with imposed myopic defocus and thinning with imposed hyperopic defocus. This study investigated the choroidal response to myopic defocus in children and adults using spectral domain optical coherence tomography (SD-OCT). Methods: Participants ages 6-45 years (n = 46) were enrolled. Measurements took place between 8:00 am and 10:00 am to minimize effects of diurnal variation. Baseline measurements included biometry and autorefraction. Participants wore their distance correction with an additional +0.50 D both eyes and viewed a black and white movie on a screen at 2 m for 10 min. Two SD-OCT images were collected for each eye, then +3 D was added over the distance correction to the left eye. Participants continued to watch the movie, and SD-OCT images were collected of both eyes every 10 minutes for 50 minutes. SD-OCT images were manually segmented to determine choroidal thickness at each time point, and analyzed with repeated measures ANOVA to assess changes in choroidal thickness by age group (6-17, 18-30, and 31-45 years). Results: Data are presented for 37 subjects. Over the 50-minute experimental session, the choroidal thickness of the left experimental eye (mean ± SEM) significantly increased from 338.7 ± 12.5 μm to 346.6 ± 12.6 μm, representing an increase of 7.9 ± 1.5 μm (P < .001). The choroidal thickness of the right control eye significantly decreased from 349.1 to 337.4 μm, representing a decrease of 11.7 ± 1.3 μm (P < .001). The relative thickening of the experimental eye compared to the control eye at 50 minutes was 19 ± 2.1 μm. There were no significant interactions between time and age group (P > .05 for both eyes and the relative difference). Conclusion: The findings demonstrate that the choroid of children and adults significantly thickens in response to short-term, full-field myopic defocus. The magnitude of the response was similar in children and in adults. Findings will contribute to our understanding of the role of the choroid in ocular responses to the visual environment.Item Objective Measurement of Light Exposure and Refractive Error in Children(2018-08) Sajjadi, Auzita; Ostrin, Lisa A.; Ritchey, Eric R.; Berntsen, David A.Purpose: An increase in outdoor time in high ambient light levels has been found to be protective against myopia onset in multiple studies. Objective measurements of light exposure and physical activity can more accurately quantify factors partially leading to myopia progression. In this one year longitudinal study, a wrist-worn device was used for continuous measurements of light exposure, physical activity and sleep to compare with subjective measurements. Objective data were also evaluated between parents and children, and across school and summer sessions. Methods: Children (n = 60) wore an actigraph device continuously for three two-week sessions to quantify light exposure, activity, and sleep. Spherical equivalent refractive error (SER) of the cycloplegic autorefraction was measured at baseline to classify subjects by refractive error. Parents answered an activity questionnaire, and a subset of parents also wore an actigraph device to compare parent-child behaviors (n = 33). Actigraph data were compared to subjective data from the questionnaire. Additionally, children’s objective data were analyzed by season. Results: Average age (±SD) of subjects at enrollment was 7.60 ± 1.80 years. At baseline there were 5 hyperopes, 47 emmetropes, and 8 myopes enrolled. By the end of the study, 3 hyperopes, 47 emmetropes, and 10 myopes were present. Average SER was +0.86 ± 1.40 D at baseline (ranging from -2.41 to +7.75 D). Objective measurements of daily light exposure showed that children spent an average of 1:24 ± 0:04 (hr:min) outdoors during school sessions and 1:48 ± 0:06 hr:min during summer sessions. The amount of time spent outdoors in the summer was significantly greater than the fall (p < 0.001) and spring (p < 0.05). Myopes were found to have spent 0:39 hr:min less per day outdoors during the summer session than emmetropes, although this did not reach statistical significance (p = 0.055). Subjectively, parents underestimated time outdoors during school sessions by 0:19 hr:min (p < 0.001) and a significant correlation was found between parent and child time spent outdoors (p < 0.05). Physical activity and sleep were not significantly different between seasons. Conclusion: Significant differences in light exposure across school and summer sessions were observed. Additionally, the significant relationship between parent and child outdoor time suggests the possible presence of a behavioral component to the development of myopic refractive errors. Future studies with increased numbers of emmetropic and myopic children utilizing objective measurement techniques may serve to clarify the role of light exposure in myopia pathophysiology and provide behavioral recommendations for children to prevent myopia and slow progression.Item Objective Measurement of Light Exposure and Refractive Error in Children(2018-08) Sajjadi, Auzita; Ostrin, Lisa A.; Ritchey, Eric R.; Berntsen, David A.Purpose: An increase in outdoor time in high ambient light levels has been found to be protective against myopia onset in multiple studies. Objective measurements of light exposure and physical activity can more accurately quantify factors partially leading to myopia progression. In this one year longitudinal study, a wrist-worn device was used for continuous measurements of light exposure, physical activity and sleep to compare with subjective measurements. Objective data were also evaluated between parents and children, and across school and summer sessions. Methods: Children (n = 60) wore an actigraph device continuously for three two-week sessions to quantify light exposure, activity, and sleep. Spherical equivalent refractive error (SER) of the cycloplegic autorefraction was measured at baseline to classify subjects by refractive error. Parents answered an activity questionnaire, and a subset of parents also wore an actigraph device to compare parent-child behaviors (n = 33). Actigraph data were compared to subjective data from the questionnaire. Additionally, children’s objective data were analyzed by season. Results: Average age (±SD) of subjects at enrollment was 7.60 ± 1.80 years. At baseline there were 5 hyperopes, 47 emmetropes, and 8 myopes enrolled. By the end of the study, 3 hyperopes, 47 emmetropes, and 10 myopes were present. Average SER was +0.86 ± 1.40 D at baseline (ranging from -2.41 to +7.75 D). Objective measurements of daily light exposure showed that children spent an average of 1:24 ± 0:04 (hr:min) outdoors during school sessions and 1:48 ± 0:06 hr:min during summer sessions. The amount of time spent outdoors in the summer was significantly greater than the fall (p < 0.001) and spring (p < 0.05). Myopes were found to have spent 0:39 hr:min less per day outdoors during the summer session than emmetropes, although this did not reach statistical significance (p = 0.055). Subjectively, parents underestimated time outdoors during school sessions by 0:19 hr:min (p < 0.001) and a significant correlation was found between parent and child time spent outdoors (p < 0.05). Physical activity and sleep were not significantly different between seasons. Conclusion: Significant differences in light exposure across school and summer sessions were observed. Additionally, the significant relationship between parent and child outdoor time suggests the possible presence of a behavioral component to the development of myopic refractive errors. Future studies with increased numbers of emmetropic and myopic children utilizing objective measurement techniques may serve to clarify the role of light exposure in myopia pathophysiology and provide behavioral recommendations for children to prevent myopia and slow progression.Item Ocular and Systemic Diurnal Rhythms in Emmetropic and Myopic Adults(2019-05) Burfield, Hannah; Ostrin, Lisa A.; Berntsen, David A.; Patel, Nimesh B.Purpose: Evidence suggests that diurnal rhythms and light exposure patterns may influence the development of refractive error. This study investigated diurnal variations in anterior and posterior segment biometry and assessed differences between myopic and emmetropic adults. Ocular and systemic diurnal rhythms were also examined in relation to objectively measured light exposure and refractive error. Methods: Healthy subjects (n = 42, 23-41 years old) underwent biometry and spectral domain optical coherence tomography imaging (SD-OCT) every 4 hours (h) for 24 h. Subjects were in darkness from 11:00 pm to 7:00 am. Central corneal thickness, corneal power, anterior chamber depth, lens thickness, vitreous chamber depth, and axial length were measured. Thicknesses of the total retina, photoreceptor outer segments + retinal pigment epithelium (RPE), photoreceptor inner segments, and choroid for a 3mm and 6mm annulus were determined. Additional measurements taken at each time point included blood pressure, heart rate, body temperature, and intraocular pressure (IOP). Mean ocular perfusion pressure (MOPP) was calculated. Saliva was collected for melatonin and cortisol analysis. Subjects wore a light, sleep, and activity monitor for one week prior to measurements. Acrophase and amplitude for each parameter were compared between refractive error groups and relationship to light exposure was examined. Results: All ocular and systemic parameters except anterior chamber depth demonstrated significant diurnal variations. Amplitude of axial length variation (35.71 ± 19.40 μm) was in antiphase to choroid variation (25.65 ± 2.01 μm, P < 0.001). The central 1 mm retina underwent variation of 5.03 ± 0.23 μm with a peak at 12 h (p < 0.001), while photoreceptor outer segment + RPE thickness peaked at 4 h and inner segment thickness peaked at 16 h. Diurnal variations in retina and choroid were observed in the 3 and 6 mm annuli. Melatonin increased following light offset with a peak at 3.19 h, while cortisol peaked after light onset at 8.86 h. IOP peaked at 11.24 h, with a variation of 4.92 ± 1.57 of mmHg, in anti-phase with MOPP, which peaked at 22.02 h. No parameter demonstrated a difference in diurnal rhythm between refractive error groups except for body temperature and MOPP. Conclusion: Ocular and systemic diurnal rhythms were observed over 24 hours in adults. While differences in baseline parameters were found between refractive error groups, diurnal rhythms were not significantly different between myopes and emmetropes, except for body temperature and MOPP. Amplitudes of daily variations were not correlated with light exposure.Item Optical Profiles, Visual Performance, and Modelling Optical Changes with Multifocal Contact Lenses(2023-08) Nti, Augustine Nyarko; Berntsen, David A.; Marsack, Jason D.; Porter, Jason; De Gracia, PabloPurpose: Multifocal contact lenses are increasingly being prescribed for myopia control, and new lens designs are being developed and studied. This series of studies sought to understand the optical profiles of current multifocal contact lenses used for myopia control and how they affect visual performance, and to determine if optical modelling can be used to predict the effect of multifocal lenses on central and peripheral refraction. Methods: Four experiments were conducted. (1) The optical profiles of multifocal contact lenses were measured using a lens profiler. (2) Contrast sensitivity with a single vision and two multifocal contact lenses were measured and compared under photopic and mesopic conditions. (3) Wide-field optical eye models were generated using both measured and published biometry to determine how well these optical models can replicate measured central and peripheral ocular aberrations of individual eyes. (4) The optical eye models were used to predict central and peripheral refraction with a single vision and multifocal contact lens. Results: (1) The NaturalVue Multifocal has an increase in plus power closer to center and incorporates a higher maximum add compared to the Biofinity and Proclear Multifocal “D” lenses. Within each lens design, distance lens power affected add distribution. (2) The NaturalVue and Biofinity “D” contact lenses reduce distance contrast sensitivity under both photopic and mesopic conditions, but do not affect near contrast sensitivity. (3) The optical models developed were able to replicate aberrations of individual eyes, but the models generated by optimizing measured biometry data were more accurate than if optimizing using only published biometry data. (4) Optical eye models were generally able to predict central and peripheral refraction with a single vision and the Biofinity “D” multifocal contact lens to within ±0.25D of refractions measured with an aberrometer, but accuracy was reduced at an eccentricity of 20° on the nasal retina. Conclusion: Multifocal contact lenses differ in the amount and distribution of plus power based on lens design and labelled distance lens power, and these lenses cause reductions in contrast sensitivity. Optical modelling can be used to replicate aberrations of individual eyes and predict changes in peripheral refraction when a multifocal contact lens is worn.Item Peripheral Autorefraction Repeatability and Peripheral Defocus of Myopic Eyes with Spherical Soft Contact Lenses(2016-05) Moore, Kelly E.; Berntsen, David A.; Manny, Ruth E.; Marsack, Jason D.Purpose: Peripheral retinal defocus has been implicated in the progression of myopia. The purpose of this thesis was to assess the repeatability of peripheral autorefraction, and to determine the effect of commercially-available soft contact lenses on peripheral defocus of myopic eyes. Methods: Twenty-five young adults with spherical equivalent refractions between –0.50 D and –6.00 D were enrolled. Cycloplegic autorefraction of the right eye was measured centrally and ±20°, ±30°, and ±40° from the line of sight along the nasal and temporal retina using a modified Grand Seiko WAM-5500 autorefractor. Experiment 1) The between-visit repeatability of peripheral autorefraction measurements using the Grand Seiko was determined in normal eyes. Measurements were made at two visits separated by 1 to 15 days. Five autorefraction measurements at each location were converted to vector space and averaged. Between-visit repeatability was evaluated by plotting the difference versus the mean of the measurements at the two visits (bias) and by calculating the 95% limits of agreement (LoA). Experiment 2) Four commercially-available spherical soft contact lenses (Biofinity, Acuvue2, PureVision2, and Air Optix Night & Day Aqua) were used to correct each subject. Five measurements per location were converted to power vectors and averaged. Spherical equivalent defocus (M) was used to calculate relative peripheral defocus (RPD) while wearing each contact lens and relative peripheral refraction (RPR) with no lens on the eye by taking the difference between each peripheral measurement and the central measurement. Analyses were conducted using repeated-measures analyses of variance (RM-ANOVA) and Benjamini-Hochberg adjusted post-hoc t-tests, when indicated. Results: The mean age (±SD) and central spherical equivalent refractive error were 24.0 ± 1.3 years and -3.45 ± 1.42 D, respectively. Experiment 1) There was no significant between-visit bias for any refractive component evaluated (M, J0, J45, and RPR) at any location measured (all p > 0.05). The 95% LoA (repeatability) for defocus (M) was ±0.21 D centrally. RPR repeatability decreased with increasing eccentricity to ±0.67 and ±0.82 D at 40 degrees nasally and temporally on the retina, respectively. Experiment 2) PureVision2 did not change relative peripheral defocus (p=0.33). Acuvue2, Biofinity, and Air Optix Night & Day Aqua caused a significant myopic shift on the temporal retina (all p<0.02). Conclusion: With knowledge of the repeatability of on- and off-axis cycloplegic autorefraction with the Grand Seiko, changes in peripheral measurements can be properly interpreted in longitudinal studies. Overall, these results show that the design of spherical soft contact lenses can influence the peripheral defocus profile experienced by a myopic eye. Though spectacles have been reported to increase peripheral hyperopia, several contact lenses tested reduced peripheral hyperopia. Longitudinal studies are required to more fully understand the impact of peripheral defocus on myopia progression and eye shape.Item Peripheral Defocus and Myopia Progression in Myopic Children Randomly Assigned to Wear Single Vision and Progressive Addition Lenses(Investigative Ophthalmology & Visual Science, 2013-08) Berntsen, David A.; Barr, Christopher D.; Mutti, Donald O.; Zadnik, KarlaPurpose: To determine the effect of progressive addition lenses (PALs) and single vision lenses (SVLs) on peripheral defocus in myopic children, and to compare the effect of myopic versus hyperopic peripheral defocus on foveal myopia progression. Methods: Eighty-four myopic children aged 6 to 11 years with spherical equivalent (SE) cycloplegic autorefraction between −0.75 diopters (D) and −4.50 D were randomly assigned to wear SVLs or PALs. Aberrometry measurements of the eye and spectacles were made centrally, 30° nasally, temporally, and superiorly, and 20° inferiorly on the retina using a Complete Ophthalmic Analysis System for Vision Research (COAS-VR). The association between peripheral defocus and the 1-year change in central myopia was investigated. Results: SVLs caused a hyperopic shift in peripheral defocus at all locations (all P ≤ 0.0003). PALs caused a myopic shift in peripheral defocus in three of four locations measured (all P ≤ 0.01) with the greatest shift superiorly due to the PAL addition (−1.04 ± 0.30 D). Superior retinal defocus when wearing either SVLs or PALs was associated with the 1-year change in central myopia. The adjusted 1-year change in central SE myopia was −0.38 D for children with absolute superior myopic defocus (n = 67) and −0.65 D for children with absolute superior hyperopic defocus (n = 17; difference = 0.27 D; P = 0.002). Conclusions: PALs caused a myopic shift in peripheral defocus. Superior myopic defocus was associated with less central myopia progression. These data support the continued investigation of optical designs that result in peripheral myopic defocus as a potential way to slow myopia progression. (ClinicalTrials.gov number, NCT00335049.)Item Quantifying the Optical, Physical, and Predicted Visual Consequences of Daily Cleaning on Conventional and Wavefront-Guided Scleral Lenses(2021-05) Wilting, Sarah; Marsack, Jason D.; Applegate, Raymond A.; Berntsen, David A.Purpose: To test whether an equivalent of 12 months of manual cleaning alters optical aberrations, base curve or predicted visual performance of conventional and wavefront-guided scleral contact lenses. Methods: Twelve scleral lenses (4 repeats of 3 designs, A-C) were manufactured in Boston XO material. Design A: –5.00 D defocus; Design B: –5.00 D defocus with –0.153 µm vertical coma; Design C: –5.00 D defocus with a full custom wavefront-guided (WFG) correction (2nd - 5th Zernike radial orders) of an eye with severe keratoconus. One lens of each design group served as a control and was not cleaned. To simulate a year of cleaning, 7 individuals cleaned 9 lenses (3 from each group) twice a day for 27 days using the palm technique and commercially available cleaners, resulting in 378 cleanings of each lens. Lens aberrations were optically profiled and base curve radii were measured at baseline and after every 42nd cleaning. Differences in higher order root mean square (HORMS) wavefront error (WFE) and base curve radii associated with cleaning were compared to clinical benchmarks using sign tests. Given that aberrations interact with one another, the change over time in the visual Strehl ratio was used to estimate the predicted change in visual acuity associated with manual cleaning. Results: For the experimental lenses, median change in Seidel spherical dioptric power was +0.01D (range: +0.001D to +0.023D). Median change in HORMS WFE was 0.013 µm (range:0.008 to 0.019 µm). Median percent change in HORMS in the three wavefront-guided lenses was 0.96% (max = 1.25%). Median change in base curve radii was 0.00 mm, with all lenses exhibiting changes (P = .002), less than the ANSI tolerance of 0.05 mm. The predicted change in visual acuity derived from the visual Strehl ratio for all coma and wavefront-guided lenses was less than 2.5 letters. Conclusion: Cleaning scleral contact lenses in a manner consistent with the method and number of cleanings that would occur over a 12-month period did not induce clinically significant changes in the optical properties, base curve radii of curvature or predicted changes in visual acuity of conventional or wavefront-guided scleral lenses.Item Repeatability and Validity of the Discovery System(2018-05) Nguyen, Mylan Thi; Berntsen, David A.; Anderson, Heather A.; Marsack, Jason D.Purpose: Evaluating an instrument’s repeatability and agreement are critical when utilizing it in research. The purpose of this thesis was to determine between-visit repeatability of the Discovery System aberrometer and the agreement between measurements made on two different Discovery Systems, a Grand Seiko WAM-5500 autorefractor, and the Complete Ophthalmic Analysis System (COAS-HD) aberrometer. Methods: Twenty-five healthy, young adults participated in two study visits separated by no more than 14 days. At each visit, cycloplegic measurements were made on the right eye. Experiment 1) Five measurements were made using the same Discovery System at two visits. At Visit 2, ten measurements were also made using the Grand Seiko WAM-5500. Discovery System refractive error values were calculated for a 3-mm and 6-mm pupil diameter. Between-visit repeatability and between-instrument agreement were evaluated using difference versus mean plots and calculating the 95% limits of agreement (LoA). Experiment 2) At Visit 2, five measurements were also made on a second Discovery System and the COAS-HD. Instrument order was randomized at each visit. Zernike coefficients were calculated over a 6-mm pupil through the sixth radial order. Between-instrument agreement was assessed using difference versus mean plots and the 95% LoA. Results: The mean age (±SD) and spherical equivalent refractive error were 23.4 ± 1.7 years and -2.91 ± 1.85 D, respectively. Experiment 1) There were no between-visit differences for M, J0, J45, higher-order root mean square (RMS), third-, fourth-, fifth-, and sixth-order RMS (all p > 0.25). Repeatability for defocus and higher-order RMS were ±0.31 D and ±0.095 microns, respectively. For a 3-mm pupil, the Discovery System measured more positive values than the Grand Seiko for M, J0, and J45 (p < 0.005). For a 6-mm pupil, there was no difference between instruments for M (p = 0.45). Experiment 2) There were no differences between the two Discovery Systems for fourth- and fifth-order RMS (all p > 0.39). There was a difference in third-order RMS (p < 0.005, 0.055 microns) and sixth-order RMS (p < 0.05, -0.005 microns) with horizontal coma (C 3, 1) accounting for the majority of the difference (p < 0.001, 0.010 microns). Between the Discovery System and COAS-HD, no differences were found for fifth- and sixth-order RMS, and spherical aberration (all p > 0.10). Differences were found for third-order RMS (p < 0.001, 0.154 microns) and fourth-order RMS (p < 0.05, -0.029 microns). Horizontal coma (C 3, 1) accounted for the majority of the third-order RMS difference between the two instruments (p < 0.001, 0.230 microns). Conclusion: The Discovery System is repeatable and would be an appropriate instrument to measure cycloplegic refractive error and higher-order aberration changes. Although repeatable, this thesis found that Discovery System measurements are not interchangeable with those made on the Grand Seiko or COAS-HD. The designer of the Discovery System is in the process of completing an update to address the between Discovery System differences.Item The Effect of Bifocal Add on Accommodative Lag in Myopic Children with High Accommodative Lag(Investigative Ophthalmology & Visual Science, 2010-12) Berntsen, David A.; Mutti, Donald O.; Zadnik, KarlaPurpose: To determine the effect of a bifocal add and manifest correction on accommodative lag in myopic children with high accommodative lag, who have been reported to have the greatest reduction in myopia progression with progressive addition lenses (PALs). Methods: Monocular accommodative lag to a 4-D Badal stimulus was measured on two occasions 6 months apart in 83 children (mean ± SD age, 9.9 ± 1.3 years) with high lag randomized to wearing single-vision lenses (SVLs) or PALs. Accommodative lag was measured with the following corrections: habitual, manifest, manifest with +2.00-D add, and habitual with +2.00-D add (6-month visit only). Results: At baseline, accommodative lag was higher (1.72 ± 0.37 D; mean ± SD) when measured with manifest correction than with habitual correction (1.51 ± 0.50; P < 0.05). This higher lag with manifest correction correlated with a larger amount of habitual undercorrection at baseline (r = −0.29, P = 0.009). A +2.00-D add over the manifest correction reduced lag by 0.45 ± 0.34 D at baseline and 0.33 ± 0.38 D at the 6-month visit. Lag results at 6 months were not different between PAL and SVL wearers (P = 0.92). Conclusions: A +2.00-D bifocal add did not eliminate accommodative lag and reduced lag by less than 25% of the bifocal power, indicating that children mainly responded to a bifocal by decreasing accommodation. If myopic progression is substantial, measuring lag with full correction can overestimate the hyperopic retinal blur that a child most recently experienced. (ClinicalTrials.gov number, NCT00335049.)Item The Effects of Center-Near and Center-Distance Multifocal Contact Lenses on Peripheral Defocus and Visual Acuity(2020-05) Hair, Lea; Berntsen, David A.; Richdale, Kathryn L.; Ritchey, Eric R.Purpose: Multifocal soft contact lenses (MFCLs) are being used for myopia control. This project compares four commercially-available MFCLs (one center-near design and three center-distance designs) to determine their effect on high-contrast and low-contrast logMAR visual acuity (HCVA/LCVA) and changes in retinal defocus along the horizontal meridian of myopic eyes. Methods: Two cohorts of twenty-five non-presbyopic myopic adults (-0.50 to -6.00 D spherical equivalent (SE) myopia and < 1.00 D cylinder) were enrolled. Cohort 1 was fitted with Proclear D and Biofinity D MFCL (center-distance, +2.50D add) and cohort 2 with NaturalVue MFCL (center-distance) and Clariti 1-Day MFCL (center-near, high add), in random order. Visual acuity was optimized with spherical over-refraction. HCVA and LCVA were obtained with each lens and with SE spectacle correction. Cycloplegic autorefraction was performed with each lens and without along the line of sight and at nasal and temporal retinal locations. Data were analyzed with repeated-measures ANOVAs and post-hoc t-tests, when indicated. Results: Compared to SE spectacle correction, Clariti 1-Day MFCL reduced HCVA (1.5 lines) and LCVA (2 lines), and NaturalVue MFCL reduced LCVA (1 line; all P < .05) with no other reductions with the other MFCLs tested. Changes in defocus at each retinal location differed between MFCL designs (lens x location; both P < .0001). The Clariti 1-Day MFCL caused hyperopic changes at multiple peripheral locations (all P < .05). The NaturalVue MFCL caused myopic changes centrally and hyperopic changes at 40° nasal and 30° temporal (all P < .05). The Proclear D and Biofinity D MFCLs caused myopic changes at multiple peripheral locations (all P < .05). Conclusion: The center-near Clariti 1-Day MFCL significantly reduced both HCVA and LCVA and caused hyperopic changes in defocus at multiple peripheral locations, limiting its potential use for myopia control. The center-distance MFCLs did not affect HCVA, but some designs reduced LCVA. Both the Biofinity D and Proclear D caused myopic changes in retinal defocus. The NaturalVue MFCL caused myopic defocus changes centrally but hyperopic changes in the far periphery. Whether differences in center-distance defocus profiles influence the ability to slow myopia progression needs further investigation.Item The Role of Corneal Astigmatism When Fitting Orthokeratology Contact Lenses(2019-08) Tomiyama, Erin S.; Richdale, Kathryn L.; Marsack, Jason D.; Berntsen, David A.Purpose: About one-third of children aged 5-17 years old have astigmatism. Children with increasing astigmatism can also have an accompanying increase in myopia via axial elongation. All of the randomized clinical trials to date have excluded patients with more than 1.50 D of astigmatism and there are limited data on the success of orthokeratology in patients with moderate to high astigmatism. The purpose of this thesis was to assess the fit of sphere and toric lenses and quantify the amount of corneal astigmatism corrected, and to determine the effect of peripheral elevation and central corneal astigmatism on toric orthokeratology fitting. Methods: Two different studies were performed. The first was a retrospective analysis on 32 eyes of 16 subjects, half fitted with sphere and half with toric orthokeratology lenses. The post-treatment data after 1-3 months of successful nightly wear were compared to pre-treatment data to analyze the change in corneal astigmatism. The second study was a prospective analysis of the Pentacam tomography of 25 moderate refractive myopic astigmats (1.25 to 3.50 DC), ages 19 to 38 years. A subset of 20 subjects were fitted with Paragon Dual Axis Corneal Refractive Therapy (CRT) lenses that were worn for 10 2 days. Results: Three methods of analysis showed that the decrease in corneal astigmatism for the spherical lens group was 0.10 - 0.22 D, which was approximately 22 - 31% correction, and the toric group was 0.29 - 0.57 D, which was 20 - 36% correction (all p < 0.006). There was a strong correlation between central corneal astigmatism and corneal elevation at the 4, 6, and 8 mm chords (r = 0.979, r = 0.961, r = 0.927, respectively; all p < 0.001). After Dual Axis lens wear, the average decentration of the treatment zone from the pupil center was 0.29 ± 0.23 mm temporal and 0.13 ± 0.26 mm inferior. Conclusion: Toric orthokeratology lenses correct slightly more corneal astigmatism than spherical lenses. Central corneal astigmatism was highly correlated to peripheral elevation and may be a more expedient measure for clinical use when fitting toric orthokeratology lenses. The amount of treatment zone decentration with toric lenses was minimal which may lead to better visual performance.Item Visual Interaction of Zernike Aberration Terms from 2nd to 5th Radial Orders with Vertical Coma(2020-08) Hu, Chuan; Marsack, Jason D.; Richdale, Kathryn L.; Berntsen, David A.Purpose: Eyes with keratoconus suffer from an increased level of higher-order aberrations and decreased visual performance, even when corrected by conventional rigid contact lenses. This study aimed to characterize the visual interactions between the dominant residual aberration seen in this population (positive vertical coma: C7) and 2nd to 5th radial order Zernike aberration terms. Methods: The experiment proceeded in two parts. In part 1, individual Zernike aberration terms from the 2nd to 5th radial orders were combined in 0.05 μm steps from -2.00 to +2.00 μm with +1.00 μm of C7. The resulting combinations were used to calculate the visual Strehl ratio (VSX), which was used as a surrogate for the relative beneficial/deleterious impact of the combined condition, compared to C7 alone. For conditions where an interaction was predicted to provide the largest improvement (C6 and C17), high-contrast logMAR acuity charts were constructed to simulate the manner in which the combined condition defines the retinal image of the blurred chart. These charts were then read by three well-corrected, typically-sighted individuals through a 3.0-mm artificial pupil. In part 2, the interactions that were predicted to have a deleterious (rather than beneficial) visual interaction with C7 were characterized in greater detail. Results: In part 1, all aberration-containing conditions led to a reduction in visual image quality compared to the aberration-free condition. Levels of C6, C10, C15, C16, and C17 were identified that resulted in higher visual image quality than was observed with +1.00 μm of C7 alone. The acuities of subjects reading convolved charts had a strong correlation with the predicted performance from simulation (C6: r2 = 0.80, and C17: r2 = 0.76). In part 2, all combinations with C4, C5, C11, C12, C13, C18, and C19 were predicted to have worse logVSX than C7 alone. Conclusion: While most interactions reduced visual image quality, limited combinations provided a clinically relevant beneficial effect in the presence of C7. Future work will examine whether these effects persist as the aberration structure of the eye is made increasingly complex, up to the point it mimics an individual with keratoconus.Item Visual Performance of Center-Distance Multifocal Contact Lenses Fit Using a Myopia Control Paradigm(2021-05) Gregory, Hannah Renea; Ritchey, Eric R.; Berntsen, David A.; Cheng, HanPurpose: Multifocal contact lenses (MFCLs) are increasingly being prescribed for non-presbyopic patients (e.g., myopia control, digital eye strain, etc.). It is important to understand how these contact lenses affect visual performance. MFCLs and single vision contact lenses (SVCLs) were evaluated under several illuminations and contrast levels. Methods: Twenty-five non-presbyopic adults with -1.00 D astigmatism or less and spherical equivalent refraction (SER) between -0.75 DS and -6.00 DS at the corneal plane were enrolled and fitted binocularly in three contact lens designs using a myopia control paradigm. Two lenses were center-distance MFCLs (Biofinity “D” +2.50 add, NaturalVue Multifocal) and one was a spherical SVCL (Biofinity). Subjects were masked to the lens type. High-(HC) and low-contrast (LC) logMAR visual acuity (VA) was measured at distance in photopic, mesopic, and mesopic with glare lighting. Photopic high-contrast acuity and reading speed were measured at near. Data were analyzed using repeated-measures analyses of variance (RM-ANOVA) with adjusted post-hoc t-tests, when appropriate. Results: The mean (± SD) age and SER were 24.1 ± 1.5 years and OD: –3.38 ± 1.53 DS (range –1.00 to –5.00 DS), OS –3.29 ± 1.66 DS (range –0.75 to –5.75 DS), respectively. HC and LCVA depended on lighting and lens type (lens x contrast x lighting interaction; P = .015). HC was always better than low (all P < .05). The acuity loss in photopic HCVA between SVCLs and MFCLs was statistically significant, approximately 1.5 to 2 letters (P = .017). Mesopic, HCVA with MFCLs was 4 to 5 letters worse than SVCLs (P < .001). All lenses performed better in photopic lighting (all P < .001). Photopic, LCVA with both MFCLs was 5-6 letters worse than SVCLs. For mesopic LCVA without glare, loss was just over 2 lines for MFCLs compared to SVCLs. Reductions in LCVA between photopic and mesopic lighting differed by lens types (SVCL versus MFCLs; P < .0001). In mesopic lighting, the addition of glare reduced VA by about 3 letters (0.065 logMAR; P < .00001); VA reduction did not depend on lens design (SVCL vs MFCLs; P = .17). Reading performance in words per minute (WPM) was worse with MFCLs (Biofinity MFCL 144 ± 22 WPM, NaturalVue multifocal 144 ± 28 WPM) than with SVCLs (156 ±23 WPM; P = .019) regardless of letter size (P = .13). No difference in visual acuity between the MFCLs was detected (all P > 0.05). Conclusion: Compared to the SVCL, both MFCL designs resulted in reductions in distance VA under photopic low-contrast and mesopic, high- and low-contrast conditions. Additional reductions in VA were observed with glare, but these reductions did not differ between lens designs. High-contrast VA does not fully describe the effect of MFCL optics on visual acuity. Additional work is needed to better ascertain visual performance with multifocal lens designs.