Cortical dynamics in visual areas induced by the first use of multifocal contact lenses in presbyopes.

A common non-spectacle strategy to correct presbyopia is to provide simultaneous images with multifocal optical designs. Understanding the neuroadaptation mechanisms behind multifocal devices usage would have important clinical implications, such as predicting whether patients will be able to tolerate multifocal optics. The aim of this study was to evaluate the brain correlates during the initial wear of multifocal contact lenses (CLs) using high-density visual evoked potential (VEP) measures. Fifteen presbyopes (mean age 51.8 ±â€¯2.6 years) who had previously not used multifocal CLs were enrolled. VEP measures were achieved while participants looked at arrays of 0.5 logMAR Sloan letters in three different optical conditions arranged with CLs: monofocal condition with the optical power appropriate for the distance viewing; multifocal correction with medium addition; and multifocal correction with low addition. An ANOVA for repeated measures showed that the amplitude of the C1 and N1 components significantly dropped with both multifocal low and medium addition CL conditions compared to monofocal CLs. The P1 and P2 components showed opposite behavior with an increase in amplitudes for multifocal compared to monofocal conditions. VEP data indicated that multifocal presbyopia corrections produce a loss of feedforward activity in the primary visual cortex that is compensated by extra feedback activity in extrastriate areas only, in both early and late visual processing.

Reduction of Myopic Progression Using a Multifocal Soft Contact Lens: A Retrospective Cohort Study.

Purpose: To evaluate myopia progression over an approximately 6-year follow-up period in children and young adults wearing a commercially available, daily disposable, soft multifocal contact lens with an extended depth of focus (center distance) design. Methods: This retrospective cohort analysis included data from 196 patients of mean (SD) age 12.3 (2.7) years (range, 5-20 years), fit with the NaturalVue Multifocal (NVMF) contact lens at 15 practices in the United States over 6 years. All patients showed at least -0.50D of myopic progression in at least one eye prior to wearing the lens. Data from the right eye were analyzed. One-way ANOVA with Tukeys post-hoc t-tests were used for statistical analysis, with a significance level set at P < 0.05. Results: After wearing these lenses for 6-72 months, the average myopia progression slowed by approximately 0.84 D or 85% compared to baseline, which was statistically significant at all time points (P < 0.0001). Frequency distribution revealed that 91% of wearers showed a decrease in myopia progression compared to baseline, with 79% of wearers showing a ≥70% reduction in myopia progression. The average change in axial length in a subset of the population over 47 months of follow-up was approximately 0.10 mm/year. Compared with changes expected in an age- and ethnicity-matched myopic virtual control group obtained from published meta-analysis data, both myopic refractive error progression and axial elongation were significantly lower in NVMF wearers at 12, 24 and 36 months (P < 0.001). Analysis of the age- and ethnicity-matched virtual control group predicted that the Cumulative Absolute Reduction of axial Elongation (CARE) value over 3 years would be 0.45 mm. Conclusion: Wearers of the soft multifocal contact lens displayed significant reductions in myopia progression throughout a follow-up period of 6 years.

Exploring contact lens opportunities for patients above the age of 40 years.

PURPOSE: Contact lenses offer a good option for patients with presbyopia, especially with improved optical designs available in modern multifocal contact lenses. Due to the ageing population there is good opportunity to increase contact lens penetration by managing these patients better. However, multifocal contact lenses achieve low penetration in the market. METHODS: A questionnaire was administered to people aged above 40 years, to investigate their perceptions of contact lenses for presbyopia. Only people, with presbyopia, who were existing contact lens wearers or willing to try contact lenses were included. Participants were recruited from United Kingdom (UK), United States of America (USA), Netherlands, Germany, France, Spain and Italy. RESULTS: Data from 1540 participants above the age of 40 years was collected, 57.9% were females and 42.1% males. Overall, 50.8% of the participants wore contact lenses, but contact lens wear was less common amongst older participants. Some data supported earlier studies, such as 6.1% wore gas permeable lenses. However, only 25% of the contact lens wearers used multifocal contact lenses. The reasons the participants wanted to wear contact lenses were similar to younger patient such as sports or cosmesis reasons. Reasons why participants had dropped out of contact lenses included discomfort and dry eye related issues. Poor visual performance with contact lenses was a reason to dropout of contact lenses for the older participants. CONCLUSIONS: The study highlights some failings by eye care practitioners in the management of patients with presbyopia. It seems that patients of this age group are seeking suggestions and recommendations from their eye care practitioner including upgrading contact lenses and dual wear options. The day-to-day problems encountered by the contact lens wearers in this study seem to be, in the main, things that could be easily tackled by additional counselling and instruction from the eye care practitioners.

Short-term delay in neural response with multifocal contact lens might start at the retinal level.

INTRODUCTION: Multifocal simultaneous imaging challenges the visual system to process the multiple overlaps of focused and defocused images. Retinal image processing may be an important step in neuroadaptation to multifocal optical images. Our aims are, firstly to evaluate the short-term effect of different multifocal contact lenses (MF) on retinal activity in young healthy subjects (Experiment#1) and secondly, to evaluate any changes in retinal activity in presbyopic patients fitted with MF over a 15-day period (Experiment#2). METHODS: In Experiment-#1, 10 emmetropic healthy young subjects were included to evaluate the short-term effect of different MFs designs. In Experiment #2, 4 presbyopic subjects were included to wear MF for 15 days. Following the ISCEV Standards, multifocal electroretinograms (mfERGs) were recorded to evaluate different retinal regions under different conditions: with single vision contact lens (SVCL) and with center-distance and center-near MF. RESULTS: In Exp#1 the peak time of N1, P1 and N2 were found to be delayed with the MF (p ≤ 0.040). There was a significant reduction for N1 amplitude in all retinal regions (p < 0.001), while for P1 and N2 amplitudes this reduction was more significant in the peripheral regions (p < 0.005, ring 5 to 6). With center-near MF the mean response density (nV/deg2) showed a significant decrease in all wave components of the mfERGs response, particularly from Ring 3 to Ring 6 (p < 0.001, all Rings). In Exp#2, the mean mfERG response is similar between SVCL and center-distance MF, while center-near MF showed an increase in implicit time N1 and P1 on day 1 that tends to recover to baseline values after 15 days of MF wear. CONCLUSIONS: significant changes in the mfERGs responses were found with the MF lens, being most noticeable with the center-near MF lens design. The present results suggest that the observed delay in cortical response described during the adaptation to multifocality may partially begin at the retina level.

Efficacy and Safety of Different Add Power Soft Contact Lenses on Myopia Progression in Children: A Systematic Review and Meta-Analysis.

BACKGROUND: In children, myopia has become a widespread and serious global public health problem. Soft multifocal contact lenses (SMCLs) have been widely studied to control myopia progression in children. However, their efficacy in myopia control in children and its adverse effects and which added power SMCLs are more effective and safer remains to be explored. OBJECTIVES: Evaluate the efficacy and safety of various add power SMCLs to slow myopia progression in children. METHOD: Eligible randomized controlled trials were retrieved from PubMed, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases. The present meta-analysis analyzed the mean differences (MD) in myopic progression, axial length, and odds ratios for adverse effects and dropout rates between SMCLs with different added powers and control groups. Changes in visual performance were also systematically evaluated. RESULTS: Seven independent studies involving 805 children were included in the present meta-analysis. At 1-year, the weighted MD (WMD) in myopia progression between SMCL and control groups was -0.22 diopters (D) (95% confidence interval [CI]: -0.56 to 0.12 D) for low add power SMCLs, 0.09 D (95% CI: 0-0.19 D) for medium add power SMCLs, and 0.2 D (95% CI: 0.13, 0.27 D) for high add power SMCLs. At 2-years, the WMD for medium add power was 0.12 D (95% CI: -0.03 to 0.27 D), and for high add power was 0.25 D (95% CI: 0.14-0.35 D). No differences were detected for adverse effects (p = 0.2) and acceptability (p = 0.74) between different added powers. Additionally, differences in visual performance changes, produced by different added powers, were not detected. CONCLUSIONS: The present meta-analysis showed that high add power SMCLs are more effective and stable to control myopia progression. Besides, the adverse effects and acceptability were not related to the added power.

A Clinical Study of the Impact of Soft Contact Lenses on the Progression of Myopia in Young Patients.

PURPOSE: To assess the impact of soft contact lenses on the progression of myopia in young patients. PATIENTS AND METHODS: The observational study included 102 patients divided into 3 groups: MFCL (multifocal contact lenses) group: 15 girls and 9 boys, aged 8-20 (= 14.12 ± 2.863) with soft multifocal contact lenses with myopia: = -3.12 D ± 1.776 D and mean myopia progression -0.23 ± 0.233D after 2 years; SVCL (single vision contact lenses) group: 30 girls and 5 boys, 11-20 years old (=15.5 ± 2.24) with myopia = -2.88 ± 2.122 D at admission and mean myopia progression -0.54 ± 0.464 D after 2 years; the spectacle (single vision glasses) group: 25 girls and 18 boys, aged 8-18 years ( = 13.65 ± 2.448) with single vision glasses with myopia: = -1.74 ± 1.412 D at admission and mean myopia progression -0.86 ± 0.489D after 2 years. Medical history and physical examination were performed every 6, 12, 18 and 24 months. Refractive error was examined using the autorefractometry after cycloplegia. RESULTS: The analysis of myopia correction after 2 years showed differences between MFCL and spectacle correction. The change in myopia progression after 2 years was statistically significant for MFCL vs SVCL and MFCL vs spectacle correction when the myopia occured before the period of intensive growth. When myopia occurred during the period of intensive growth, difference was noted for MFCL vs spectacle correction and SVCL vs spectacle correction. When myopia occurred after a period of intensive growth, no significant differences between the groups were observed. CONCLUSION: 1) Multifocal contact lenses and some single vision contact lenses (Biofinity) may be useful in the control of myopia in younger patients, slowing the progression of nearsightedness; therefore, they can be a therapeutic option in inhibiting the progression of myopia. 2) The best effects of using multifocal contact lenses occur if myopia is diagnosed before the period of intensive growth.

Multifocal contact lenses: A bibliometric study

Purpose: To analyze the state of scientific publications in multifocal contact lenses field through a bibliometric study.Methods: The database used to carry out the study was SCOPUS and contained the descriptors “multifocal contact lens”, “bifocal contact lenses”, “progressive contact lenses” and “presbyopia contact lenses”, limited to the fields of title, keywords and abstract. The indicators applied in this research were: doubling time and annual growth rate, Price’s transience index, Lotka’s law of scientific productivity, and Bradford’s zones.Results: A total of 346 articles were published between 1960 and 2019. The growth in the number of publications matches the exponential adjustment slightly better (R = 0.53). The duplication time was 13.2 years. The productivity level is focused on articles with an average number of authors of just 2.06 per article. The Bradford core was formed by two journals, Optometry and Vision Science and Eye and Contact Lens.Conclusions: Research on multifocal contact lenses has exponential growth, without evidence of having reached a saturation point. The main countries in scientific production in this field are the United States and Australia. (AU)

Multifocal contact lenses: A bibliometric study.

PURPOSE: To analyze the state of scientific publications in multifocal contact lenses field through a bibliometric study. METHODS: The database used to carry out the study was SCOPUS and contained the descriptors "multifocal contact lens", "bifocal contact lenses", "progressive contact lenses" and "presbyopia contact lenses", limited to the fields of title, keywords and abstract. The indicators applied in this research were: doubling time and annual growth rate, Price's transience index, Lotka's law of scientific productivity, and Bradford's zones. RESULTS: A total of 346 articles were published between 1960 and 2019. The growth in the number of publications matches the exponential adjustment slightly better (R = 0.53). The duplication time was 13.2 years. The productivity level is focused on articles with an average number of authors of just 2.06 per article. The Bradford core was formed by two journals, Optometry and Vision Science and Eye and Contact Lens. CONCLUSIONS: Research on multifocal contact lenses has exponential growth, without evidence of having reached a saturation point. The main countries in scientific production in this field are the United States and Australia.

Impact of the pupil size - central optical zone diameter relationship on visual performance in aspheric multifocal contact lenses.

PURPOSE: To determine the impact of different central optical zone diameters (COZDs), obtained from pupil size, on the visual performance of presbyopic subjects fitted with centre-distance simultaneous-image multifocal contact lenses (SIMCLs). METHODS: Thirty-two presbyopic volunteers, between 45-58 years of age, participated in this prospective, controlled, double-blind study. Subjects were fitted with 5 centre-distance SIMCLs of variable COZD, determined from the measurement of pupil size under photopic light conditions and corresponding to 60, 70, 80, 90 and 100 % of pupil diameter. Subjects visual performance was evaluated through the measurement of distance, intermediate and near visual acuity (VA), "visual functional range" (VFR) obtained from the VA Defocus Curve (VADC) and Contrast Sensitivity Function (CSF), using a third-generation retina display iPad. RESULTS: Statistically significant differences were obtained for both distance (p = 0.01) and intermediate (p = 0.001) VA amongst designs. Best results were obtained with 80 % and 90 % COZDs compared to 60 %. No significant differences in VFR (p > 0.05) were obtained amongst the different COZDs. 90 and 100 % COZDs offered statistically significant better results at 6 and 18 cycles per degree (cpd) in the CSF, compared to the 60 and 70 % designs. CONCLUSIONS: SIMCLs with COZDs of 80-90 % and of 90-100% of photopic pupil diameter offered better distance and intermediate VA, without a decline in near performance, and superior contrast sensitivity at medium and high spatial frequencies respectively, compared to lower COZD designs.

Driving performance and road sign identification by multifocal contact lens wearers in a driving simulator.

PURPOSE: The purpose of this study was to compare sign identification distances and driving performance metrics in presbyopic participants while wearing multifocal contact lenses (MFCL) and while wearing progressive addition lens (PAL) spectacles. METHODS: 19 presbyopic participants completed PAL spectacle assessments and contact lens fitting and follow up visits before driving assessments began. These assessments occurred in a simulator equipped with a full-sized sedan on a motion platform and a 260 degree screen. Participants completed the driving task with PAL and with MFCL. Participants followed a lead car and identified signs at various distances from the road. For the two wearing conditions, comparisons of the distance along the road at which signs were identified were made using repeated measures ANOVA. Paired t-tests were used to compare driving performance for the two conditions. RESULTS: There was no statistical difference in sign identification distance between PAL and MFLC for signs 32.0 m from the road side of the road (182 ± 46 m for MFCL; 205 ± 45 m for PAL; P = 0.07) or 51.4 m from the side of the road (204 ± 43 m for MFCL; 216 ± 36 m for PAL; P = 0.3). Only signs 70.2 m from the roadside showed a significant difference (207 ± 42 m with MFCL; 232 ± 39 m with PAL; P = 0.01), All distances were greater than those required to safely stop a vehicle. There were no significant differences in the driving performance metrics between the refractive corrections. CONCLUSION: Driving performance metrics were similar for MFCL and PAL spectacles. Sign identification distances with both eyewear types were well within the distances required for safe vehicle stopping.

Visual performance with multifocal contact lenses and progressive addition spectacles.

PURPOSE: As presbyopia occurs, new visual demands create a need for clear vision at multiple distances. Many spectacle wearers adapt into progressive addition lenses (PAL) in order to see clearly at distance, intermediate, and near. A multifocal contact lens provides the ability to see at these same distances without the prismatic effects of a spectacle lens or the peripheral obstruction of a spectacle frame. No studies have been done to date comparing the effect of these types of presbyopic vision correction on a variety of tests of visual performance representative of everyday tasks. METHODS: A battery of visual performance tasks were completed by subjects while wearing their habitual PAL spectacles. These subjects were then fit with a multifocal contact lens and wore lenses for 2 weeks or more before completing the tasks again. These functional vision tests included assessments of coincidence anticipation timing, peripheral search and hand-eye coordination, and dynamic visual acuity. Following functional vision testing, subjects completed a preference survey comparing both types of refractive correction while performing common activities of daily living. RESULTS: Performance on the majority of the tests of visual performance were equivalent (P < 0.05) when comparing PAL spectacles and multifocal contact lenses. Survey results demonstrated a preference for multifocal contact lenses overall. CONCLUSION: PAL spectacles are widely prescribed for presbyopic patients. The findings of this study suggest that in addition to providing excellent vision, multifocal contact lenses provide functional vision performance equal to PAL spectacle wear and patients may prefer them over PAL spectacles.

Multifocal contact lens design, not addition power, affects accommodation responses in young adult myopes.

PURPOSE: Prolonged nearwork has been implicated in myopia progression. Accommodation responses of young-adult myopes wearing different multifocal contact lenses were compared. METHODS: Twenty adults, 18-25 years, with myopia (spherical equivalent refraction -0.50 to -5.50 D, mean -2.1 ± 1.6 D) wore five lens types in random order: Proclear single vision distance (SV), MiSight concentric dual-focus +2.00 D Add (MS), Biofinity aspheric centre distance +1.50 D Add (CD1) and +2.50 D Add (CD2) (all Coopervision), and NaturalVue aspheric (Visioneering Technologies) (NVue). Using a Grand-Seiko WAN-5500 autorefractor with binocular correction and viewing right eye accommodative responses were measured after a 10 min adaptation period at 4.0, 1.0, 0.5, 0.33 and 0.25 m distances. Dynamic measurements were taken for 4 s at 6 Hz. Accommodative stimuli and responses were referenced to 4 m (i.e., refraction differences between 4 m and nearer distances). Accommodation lags and refraction instabilities (standard deviations of dynamic responses) were determined. For comparison, results were obtained for an absolute presbyopic eye, where trial lenses counteracted the accommodation stimulus. RESULTS: For SV and MS, accommodation responses were similar to the stimulus values. For aspheric lenses CD1, CD2 and NVue, accommodation responses were approximately 1.0 D lower across the stimulus range than with SV and MS, and rates of change were approximately 0.84 D per 1 D stimulus change. MS produced greater refraction instabilities than other lenses. For the presbyope, changes in refraction matched the trial lenses, indicating that corrections due to measurement through the different lenses were not needed. CONCLUSION: Reductions in accommodation response occurred in young myopes wearing aspheric multifocal contact lenses independent of the labelled 'add' power. The concentric dual-focus MS lens produced minimal lags but had greater instability than the other lenses. The results indicate that the mechanism of multifocal contact lenses slowing myopia progression is unlikely to be through relaxing accommodation, at least in young adults.

Greater higher order aberrations induced by toric orthokeratology versus soft toric multifocal contact lens wear.

PURPOSE: Spherical orthokeratology and soft multifocal contact lenses are commonly used for myopia control and correction, but have been shown to increase spherical aberration, coma and total higher order root mean square (HORMS) aberrations. There are limited myopia control contact lens options for patients with moderate to high astigmatism. The purpose of this study was to quantify changes in higher order aberrations (HOA) in myopic astigmatic eyes fitted with toric orthokeratology (TOK) and soft toric multifocal (STM) contact lenses. METHODS: Ocular wavefront aberrations were measured in both eyes of 30 adult subjects and are reported through the 6th radial order over a 5 mm, dilated pupil. All eyes met refractive criteria of myopia (-5.00 D to plano) and cylinder (-3.50 to -1.25 D). Three measurements were taken at baseline and after 10 ± 2 days of lens wear (TOK, STM). Sixteen subjects achieved logMAR high contrast visual acuity of 0.30 or better in both eyes and were included in this analysis. Repeated measures analysis of variance and post-hoc paired t-tests were used, as appropriate, with Benjamini-Hochberg correction. RESULTS: Higher order root mean square, spherical aberration (C12), and coma RMS (C7, C8) increased with TOK (0.641 [0.222], 0.409 [0.157], 0.426 [0.187] µm, respectively) and STM (0.481 [0.107], 0.223 [0.139], 0.320 [0.130] µm, respectively) from baseline (all p < 0.001). TOK was elevated compared to STM for HORMS (p = 0.03), spherical aberration (p = 0.001) and coma RMS (p = 0.04). CONCLUSIONS: Toric orthokeratology induced more HORMS, spherical aberration and coma RMS than STM in myopic astigmats; however, both lens types showed an increase in HOA compared to baseline, which placed patients outside the age and pupil size matched normative ranges. While the optical changes that accompany these modalities are helpful for myopia management, the induction of HOAs may have unintended consequences on visual performance.

Computerised dynamic posturography for postural control assessment in subjects wearing multifocal contact lenses dedicated for myopia control.

PURPOSE: To measure body balance using computerised dynamic posturography in young adults wearing multifocal contact lenses (MFCL) with high addition powers designed for myopia control. METHODS: Twenty-four young adults (mean age: 24 years) wearing distance-centred soft MFCL (SwissLens Orbis Relax) with two different central zones (3 and 4.5 mm), two addition powers (+2 D, +4 D) and single vision control lenses. Body balance was measured on a moving platform under three viewing conditions: (1) eyes open when fixating on letters at 3 m or (2) at 40 cm, as well as (3) with the eyes closed. Parameters of body stabilisation were analysed: the rate of body stabilisation (τrelax ), the stabilisation time (Tmax ) and the number of oscillations (Nosc ). RESULTS: The MFCLs did not produce a significant difference in the mean values of the analysed parameters (p > 0.05 for τrelax, Tmax, Nosc ). However, a positive correlation was found between pupil size and Nosc and Tmax (p < 0.01), suggesting an effect of the +4 D add with the 3 mm central zone on the posturographic parameters. As was expected, dynamic body stabilisation was better with eyes open versus eyes closed (p < 0.005). CONCLUSIONS: Distance-centred MFCLs with a medium addition (+2 D) do not disturb body stabilisation in young adults. However, high additions (+4 D) with a small central zone may affect body balance control in subjects with large pupil size.

Bayesian Meta-Analysis of Myopia Control with Multifocal Lenses.

The aim of this study is to provide reliable guidelines for the mean percentage efficacy together with the 95% credibility interval in slowing down progression of myopia by a specific intervention over defined time periods, derived from a substantial number of randomised controlled clinical trials (RCTs) with consistent outcomes. Multifocal spectacles and contact lenses represent interventions with the largest number of RCTs carried out. Our meta-analyses considered 10 RCTs involving 1662 children which have tested the efficacy of progressive addition spectacle lenses (PALs). In a separate model for comparison purposes nine RCTs with 982 children trialling soft multifocal contact lenses (MFCLs) were analysed. Bayesian random-effects hierarchical models were fitted. The highest efficacy in retarding progression of the scaled sphere equivalent refraction was achieved after 12 M follow-up with the mean 28% reduction in progression and the 95% credibility interval between 21% and 35%. For comparison, the 95% credibility interval for the mean efficacy of soft MFCLs at 12 M follow up is 21% to 37%. We conclude that both multifocal spectacle and contact lenses moderately slow down progression of myopia, relative to single-vision spectacle lenses (SVLs) in the first 12 months after intervention. The relative efficacy of PALs tends to weaken after the first 12 months.

Optical and Visual Quality With Physical and Visually Simulated Presbyopic Multifocal Contact Lenses.

Purpose: As multifocal contact lenses (MCLs) expand as a solution for presbyopia correction, a better understanding of their optical and visual performance becomes essential. Also, providing subjects with the experience of multifocal vision before contact lens fitting becomes critical, both to systematically test different multifocal designs and to optimize selection in the clinic. In this study, we evaluated the ability of a simultaneous vision visual simulator (SimVis) to represent MCLs. Methods: Through focus (TF) optical and visual quality with a center-near aspheric MCL (low, medium and high near adds) were measured using a multichannel polychromatic Adaptive Optics visual simulator equipped with double-pass, SimVis (temporal multiplexing), and psychophysical channels to allow measurements on-bench and in vivo. On bench TF optical quality of SimVis-simulated MCLs was obtained from double-pass (DP) images and images of an E-stimulus using artificial eyes. Ten presbyopic subjects were fitted with the MCL. Visual acuity (VA) and DP retinal images were measured TF in a 4.00 D range with the MCL on eye, and through SimVis simulations of the same MCLs on the same subjects. Results: TF optical (on bench and in vivo) and visual (in vivo) quality measurements captured the expected broadening of the curves with increasing add. Root mean square difference between real and SimVis-simulated lens was 0.031/0.025 (low add), 0.025/0.015 (medium add), 0.019/0.011 (high add), for TF DP and TF LogMAR VA, respectively. A shape similarity metric shows high statistical values (lag κ = 0), rho = 0.811/0.895 (low add), 0.792/0.944 (medium add), and 0.861/0.915 (high add) for TF DP/LogMAR VA, respectively. Conclusions: MCLs theoretically and effectively expand the depth of focus. A novel simulator, SimVis, captured the through-focus optical and visual performance of the MCL in most of the subjects. Visual simulators allow subjects to experience vision with multifocal lenses prior to testing them on-eye. Translational Relevance: Simultaneous visual simulators allow subjects to experience multifocal vision non-invasively. We demonstrated equivalency between real multifocal contact lenses and SimVis-simulated lenses. The results suggest that SimVis is a suitable technique to aid selection of presbyopic corrections in the contactology practice.

Accuracy, inter-observer and intra-observer reliability in topography assessment of multifocal contact lens centration.

PURPOSE: To evaluate the accuracy and reliability (inter and intra-observer) of a method to assess multifocal contact lenses (MCLs) centration using a corneal topography unit. METHOD: Daily-disposable MCLs (Fusion 1 day Presbyo) were fitted on both eyes of the subjects. For each lens fit a slit lamp digital picture and videokeratograph image were taken in a rapid but randomised sequence. Photo-editing software was used to assess the position of the MCL centre with respect to pupil centre as taken from the slit lamp photograph. The position of the MCL centre was automatically detected as the point of maximum curvature from the videokeratography. Three further manual and qualitative procedures to detect MCL centre, comparing a template of CLs optic zones to the videokeratographic image were performed by 4 practitioners using 3 different algorithms to represent the topographic map. Each manual reading was repeated 3 times. RESULTS: Twenty-two subjects (11 males) aged 22.8 ± 1.9 years (range 20.8-27.0 years) were recruited. The accuracy of the 4 topographic assessments in determining the centre coordinates of the MCL with respect to SL assessment was good: no differences were found in the left eyes and although in the right eyes a more temporal and superior position of MCLs was determined (paired t-test, p < 0.05) the difference was clinically negligible (0.16 ± 0.36 mm horizontally, 0.23 ± 0.48 vertically). Amongst the 4 practitioners one-way Anova for repeated measures showed no differences for any of the 3 manual assessments. Intra-class correlation coefficient was calculated among the 3 readings for each manual procedure and was very good (between 0.75 and 0.98) in 3 practitioners and moderate (between 0.49 and 0.92) in the fourth. CONCLUSIONS: The assessment of MCL centration by performing corneal topography over the MCL is an accurate method. Furthermore, inter and intra-practitioner reliability showed by manual procedures appeared very good.

Inverting peripheral hyperopic defocus into myopic defocus among myopic schoolchildren using addition power of multifocal contact lens.

PURPOSE: The purpose was to determine the minimum near-addition power needed using Proclear® multifocal D-Design contact lens (adds: +1.50 D, +2.50 D, +3.00 D, and +3.50 D) to invert the pattern of relative hyperopic defocus in the peripheral retina into relative myopic defocus among the eyes of myopic schoolchildren. METHODS: Twenty-seven right eyes (24 females and 3 males) of 27 myopic schoolchildren aged between 13 and 15 years were included in this study. The measurements of central refraction, peripheral refraction (between 35° temporal and 35° nasal visual field in 5° steps), and lag of accommodation were conducted using the Grand-Seiko WR-5100K open-field autorefractometer initially without correction (WC), followed by with correction using four different addition powers of Proclear® multifocal D-Design contact lens in random sequence. Axial length was measured using a handheld probe ultrasound A-scan (Tomey AL-2000). RESULTS: The relative peripheral refractive error showed high hyperopic defocus of +1.08 ± 1.24 D at 35° nasal and +1.06 ± 1.06 D at 35° temporal visual field WC. All Proclear multifocal contact lenses (MFCLs) decreased the peripheral hyperopic defocus with increasing addition powers (F [2.938, 47.001] = 13.317, P < 0.001). However, only +3.00 D addition and +3.50 D addition (P = 0.001) could invert the peripheral hyperopic defocus into peripheral myopic defocus. Apart from that, the +3.00 D addition lens showed the lowest lag of accommodation (+1.10 ± 0.83 D) among the other MFCL adds (P = 0.002). CONCLUSION: A +3.00 D addition Proclear MFCL is the optimal addition power that can invert the pattern of peripheral hyperopic defocus into myopic defocus.

Visual Performance and High-Order Aberrations with Different Contact Lens Prototypes with Potential for Myopia Control.

Purpose: Contact lenses (CLs) used for myopia control incorporate variable power distribution across the optic zone potentially creating degradation of the high-order aberrations. The present study aims to evaluate the retinal image quality and visual performance in three prototypes of CLs intended to control axial elongation of the eye before they are considered for clinical trials.Methods: This is a non-dispensing cross-over, double-blind study where 30 right eyes of myopic subjects worn 3 multifocal test lenses and 1 monofocal control lens in random order. Lens 1 was a radial refractive gradient design (center distance) and Lens 2 and 3 center-near with an additional annular ring for near. Nominal add power was 2.00D, 1.50D, and 2.00D, respectively. Subjects had an age 21.96 ± 2.23 years [18-30] and mean spherical equivalent refraction M = -2.23 ± 1.50D [-0.75 to -5.50] with refractive astigmatism below -0.75D. Higher-order aberrations (HOA), glare formation (halo), high- and low-contrast LogMAR visual acuity (VA), and contrast sensitivity function (CSF) was measured under monocular conditions.Results: All individual terms of HOA and total root mean square from 3rd to 8th order increased significantly with the 3 test lenses compared to control. Between test lenses, Lens 1 increased significantly the higher HOA compared with Lens 2 and Lens 3. Halo size was significantly larger with test lenses compared with control, with Lens 1 showing the largest. VA under high-contrast conditions was similar for all lenses. Under low-contrast conditions, Lens 1 and Lens 2 performed significantly worse than control (Bonferroni post hoc correction, p < 0.001). CSF was below normal limits with Lens 1 for 3 and 6 cpd spatial frequency but was not significantly different between test lenses and control.Conclusions: Lenses with larger stabilized areas for distance vision interfere less with VA and induce lower values of HOA and image degradation.