Contrast sensitivity and visual acuity in subjects wearing multifocal contact lenses with high additions designed for myopia progression control

Optical Strategy Utilizing Contrast Modulation to Slow Myopia

A new method to slow myopia progression utilizes Diffusion Optics Technology (DOT) spectacle lenses. The proposed mechanism of action for the DOT lenses is to modulate contrast across the photoreceptor cells, leading to an altered activity of the ON and OFF pathways and slowing the progression of axial elongation. This approach is different from the current optical approaches that utilize optical defocus to reduce hyperopic defocus at the peripheral retina although central vision is fully corrected to slow myopia. Initial clinical studies with the DOT lenses have demonstrated promising results with a reduction in progression of myopia. This overview summarizes the current knowledge on myopia risk factors, the evidence for involvement of contrast signaling pathways in refractive error development, and the theories and mechanisms behind DOT lens technology. It also considers the role of contrast and the paradoxical observations given the established paradigm of form deprivation in animal models.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Do myopia control spectacle lenses with defocus incorporated multiple segments technology alter visual parameters and cortical activity?

PURPOSE

This study evaluated visual parameters and cortical activity after wearing myopia control spectacle lenses with defocus incorporated multiple segments (DIMS).

METHODS

Myopic adults between 20 and 30 years of age were enrolled. The study consisted of (1) examination of visual parameters and (2) measurement of cortical responses, while wearing single vision lenses (SVL) and MiYOSMART (MS) lenses in counterbalanced order after a two-week adaptation period. Visual parameters tested were: high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), contrast sensitivity, heterophoria, near point of convergence (NPC), stereopsis, accommodative facility and the accommodative response. Cortical responses were assessed by visual evoked potentials (VEPs), recorded from 10 electrodes placed over the parieto-occipital area.

RESULTS

MiYOSMART lenses produced slightly better HCVA than SVL (-0.25 vs. -0.21 logMAR, p = 0.02) and a larger accommodative response (MS 1.68 D; SVL 1.53 D, p < 0.001). No significant differences in LCVA, heterophoria, NPC, stereopsis or contrast sensitivity were observed. The latencies and amplitudes of the early and late components of the VEPs (C1, N1, P1, P2) did not differ significantly between lenses.

CONCLUSIONS

This study found no clinically significant differences in visual parameters or visual cortex responses between SVL and MS lenses after 2 weeks of adaptation. These results confirm the absence of adverse visual effects from DIMS lenses for myopia control.

Research Tendency and Frontiers of Multifocal Lenses in Myopic Control in the Past Two Decades: A Bibliometric Analysis

Background: This study aimed to analyze the research progress on the use of a multifocal lens for myopic control throughout the 21st century, utilizing bibliometric analysis. Methods: Publications related to multifocal lenses from 2001 to 2024 were searched on the Web of Science core collection (WoSCC) database. VOSviewer (Version 1.6.19) and Bibliometrix package (Version 4.3.0) were used to perform the bibliometric analysis. Primary information including the publication number per year, country or region, journal, keyword, and title of the literature was extracted and analyzed. Results: A total of 234 articles from 31 countries were retrieved. The number of publications related to multifocal lenses had a rapid growth phase from 2016 to 2024. The United States, Australia, China, and Spain emerged as leading contributors to the research landscape. Ophthalmic and Physiological Optics was the most popular journal in this field, and the most frequently cited article was published in Optometry and Vision Science. Myopic progression was the main topic in this research field as well as the principal keywords of emerging research hotspots. Conclusions: Our bibliometric study provides a pioneering overview of the research trends and evolution in the application of a multifocal lens for myopic control. These findings provide a deep insight into current research frontiers and hot directions, offering a valuable reference for further research.

Visual performance and quality of life in myopic adolescents with pupil-optimised multifocal versus single-vision contact lenses

CLINICAL RELEVANCE

Myopia control is a prominent area of global research, with multifocal contact lenses identified as an effective intervention for adolescents.

BACKGROUND

This study aims to evaluate the visual performance and vision-related quality of life (QoL) of myopic adolescents when corrected with pupil-optimised multifocal soft contact lenses (MFSCLs) versus single-vision contact lenses (SVCLs), with each participant serving as their own control.

METHODS

Thirty-five myopic adolescents, habitually wearing SVCLs and fitted with pupil-optimised MFSCL with mid-addition power, were recruited. The assessment included distance visual acuity (DVA), near visual acuity (NVA), maximum reading speed (MRS), reading acuity (RA), contrast sensitivity (CS), and stereoacuity (SA) in photopic conditions for both types of lenses. Vision-related QoL was quantified twice for both lens types using the National Eye Institute Visual Function Questionnaire (NEI VFQ-42), covering 13 vision-specific domains.

RESULTS

Comparisons of visual outcomes between MFSCLs and SVCLs for the same subjects revealed statistically significant differences in DVA (p = 0.010), NVA (p = 0.014), MRS (p = 0.044), and RA (p < 0.001), with SVCLs outperforming in DVA only. No significant difference in CS and SA was observed between the two lens types. According to the NEI VFQ-42, scores for clarity of vision, far vision, glare, and satisfaction with correction were higher with SVCLs, while the score for near vision was higher with MFSCLs. When fitted with MFSCLs, no significant correlations were found between pupil size and age of the patient with any visual examination parameters. However, there was a significant negative correlation between the DVA, NVA and the spherical equivalent of the lens.

CONCLUSION

MFSCLs with mid-add power significantly improve NVA, MRS, and RA, albeit with a reduction in DVA compared to SVCLs. While SVCLs were associated with better clarity of vision, far vision, and satisfaction with correction, MFSCLs offered superior performance in near vision tasks, according to the NEI VFQ-42 scores.

[Visual Performance of School-age Children Wearing Dual-Focus Soft Contact Lenses: A Randomized Controlled Trial]

Objective

To investigate the effect of wearing dual-focus soft contact lenses (DFSCL) on the visual performance of school-age children.

Methods

In this randomized controlled clinical trial, 64 children aged 8 to 12 years with spherical equivalent refraction between -0.75 D and -4.00 D were recruited in our hospital in October 2022. Using the envelope method, the subjects were evenly and randomly assigned to the control group wearing single vision spectacles (SVS) or the intervention group wearing MiSight dual-focus soft contact lenses (DFSCL) from CooperVision. Follow-up examinations were conducted once every 3 months. The corrected visual acuity, contrast sensitivity function (CSF), and the scores for National Eye Institute Refractive Error Quality of Life Instrument-42 (NEI-RQL-42) were compared between the control and intervention groups.

Results

By December 2023, a total of 58 subjects completed follow-up (30 in the SVS group and 28 in the DFSCL group). No significant difference in corrected visual acuity was observed between subjects wearing DFSCL and those wearing SVS. The CSF of the DFSCL group was comparable to that of the SVS group across the spatial frequencies of 3, 6, 12, and 18 cpd (P>0.05). According to the results of the NEI-RQL-42 survey at the 6-month follow-up, the score for ocular discomfort symptoms was 89±14 in the SVS group and 79±16 in the DFSCL group (P=0.008), reflecting that the DFSCL group had a 12.66% higher level of discomfort. For appearance, the score was 70±32 in the SVS group and 92±22 in the DFSCL group (P=0.002), showing a 31.43% improvement in the DFSCL group.

Conclusion

In addition to providing the normal visual acuity and CSF, wearing MiSight DFSCL also leads to better satisfaction with the appearance.

Utility of retinoscopy to examine peripheral refraction

PURPOSE

This study explored whether retinoscopy (RET) provides comparable results of relative peripheral refraction (RPR) to open-field autorefractometry (AR) in myopic subjects.

METHODS

Peripheral refraction was measured in 20 myopic and 20 control adult subjects. Both central and peripheral refraction (20° nasal and temporal eccentricity) were measured using RET and open-field AR. Differences in the median central spherical equivalent (SE), median RPR, and median J45/J180 power vectors between the RET and AR techniques were analyzed. Moreover, Bland - Altman plots were used to assess the agreement between RET and AR methods for RPR measurements in MG.

RESULTS

For MG, the median RPR values were positive (hyperopic shift), and no significant differences were observed between the RET and AR techniques with respect to RPR measurement. In addition, we did not observe any significant differences in the RPR values between the nasal and temporal eccentricities for either the RET or AR technique for myopic subjects. There was also a significant correlation and agreement between the RET and AR technique for RPR measurements. With respect to central refraction, the median SE was slightly more positive for the RET than for the AR technique. Inside the CG, we also found significant correlation between the RET and AR technique for RPR measurements, and we observed a myopic shift in peripheral eccentricities.

CONCLUSION

Our results show that retinoscopy may be a useful tool for objective measurements of RPR in myopic subjects and may be used interchangeably with the open-field AR method in everyday clinical practice.

Effect of Individualized Ocular Refraction Customization Spectacle Lens Wear on Visual Performance in Myopic Chinese Children

Purpose

Individualized ocular refraction customization (IORC) lenses can be individually adjusted depending on the initial relative peripheral refraction to determine the myopic defocus (MD). We aimed to compare visual performance of children wearing IORC lenses with different amounts of MD to determine whether higher MD resulted in greater visual compromise.

Methods

This study included 184 myopic children aged eight to 12 years, and 172 completed the trial. The participants were randomly assigned to wear IORC lenses with low (IORC-L, 2.50 D), medium (IORC-M, 3.50 D), or high (IORC-H, 4.50 D) MD or single-vision spectacle lenses (SVL). Distance and near best-corrected visual acuity (BCVA), contrast sensitivity function (CSF) and questionnaires were evaluated at baseline and after six and 12 months.

Results

CSF over all frequencies and distance and near BCVA were not affected by lens design (all P > 0.05). The SVL group outperformed the three IORC lens groups in terms of ghosting images at baseline, and IORC-H and IORC-M groups outperformed IORC-L group (all P < 0.001); however, no differences were observed at the six- or 12-month visit. There were no significant differences among the four groups for any other subjective variables at any of the follow-up visits regarding vision clarity, vision stability, eyestrain, dizziness, headache, or overall vision satisfaction (all P > 0.05).

Conclusions

The IORC lenses with an actual MD of 4.50 D provided acceptable objective and subjective visual performance and were well tolerated by children.

Translational Relevance

IORC lenses with an actual MD of 4.50 D provided acceptable visual performance.

Intraocular Straylight and Multifocal Soft Contact Lens Fit With a Myopia Control Approach

OBJECTIVES

Center-distance multifocal contact lenses (MFCLs) are used to slow myopia progression. We examined the effect of two MFCLs on intraocular straylight values in myopic individuals.

METHODS

Twenty-five young myopic adults were enrolled and were fit with three contact lenses (Biofinity sphere, Biofinity Multifocal, and NaturalVue Multifocal) in a random order over two study visits. Pupil size (NeurOptics VIP-300, Laguna Hills, CA) and contact lens centration were measured. Right eye intraocular straylight measurements were collected (OCULUS C-Quant; Wetzlar, Germany) and compared with a spectacle trial lens. Log straylight (LogSL) values and straylight residuals were analyzed using repeated-measures analyses of variance with Tukey-corrected post hoc t -tests.

RESULTS

The mean participant age (±SD) was 24.1±1.5 years, and right eye spherical equivalent refractive error was -3.38±1.53 DS. There was no difference in mesopic pupil size between visits ( P =0.68) and no difference in contact lens centration between lenses ( P =0.99). LogSL values differed by lens type ( P =0.004). LogSL with the spectacle trial lens was significantly greater than with each contact lens type (all P <0.05), but there were no significant differences in LogSL between the three contact lenses (all P >0.05). There was no difference between the three contact lens designs for straylight residuals ( P =0.33).

CONCLUSIONS

Measured intraocular straylight for both MFCLs was not different than with a spherical soft contact lens. A significant increase in intraocular straylight with spectacle trial lens correction was observed compared with all contact lenses.

Effect of myopia-control lenses on central and peripheral visual performance in myopic children

PURPOSE

To evaluate the short-term effects of three myopia-control lenses, which impose peripheral myopic defocus while providing clear central vision, on central and peripheral visual performance in myopic children.

METHODS

Twenty-one myopic children were enrolled in the study. Central visual performance was assessed using the quick contrast sensitivity function. Peripheral visual performance was evaluated by measuring peripheral contrast threshold and global motion perception, while subjects maintained fixation through the central portion of the lens. Single-vision spectacle lenses (SVL), spectacle lenses with highly aspherical lenslets (HAL) and defocus-incorporated soft contact (DISC) lenses were evaluated in random order, followed by orthokeratology (OK) lenses. All tests were performed monocularly on the right eye.

RESULTS

The area under the log contrast sensitivity function (AULCSF) with DISC lenses was lower than that with SVL (1.14 vs. 1.40, p < 0.001) and HAL (1.14 vs. 1.33, p = 0.001). HAL increased the temporal visual field contrast threshold compared with OK lenses (p = 0.04), and OK lenses decreased the superior visual field contrast threshold compared with that of SVL (p = 0.04) and HAL (p = 0.005). HAL also increased the peripheral coherence threshold for identifying the contraction movement compared with OK lenses (p = 0.01).

CONCLUSIONS

The short-term use of these optical interventions for myopia control exhibited measurable differences in central and peripheral visual performance. Relevant attention could be paid to these differences, especially when children switch to different treatments. DISC lenses exhibited worse central contrast sensitivity than SVL and HAL. Imposing peripheral defocus signals did not affect children's peripheral visual performance compared with SVL. However, considering the poorer peripheral visual performance provided by HAL, OK lenses are recommended for children if there are specific demands for global scene recognition and motion perception.

Assessing the rebound phenomenon in different myopia control treatments: A systematic review

PURPOSE

To review the rebound effect after cessation of different myopia control treatments.

METHODS

A systematic review that included full-length randomised controlled studies (RCTs), as well as post-hoc analyses of RCTs reporting new findings on myopia control treatments rebound effect in two databases, PubMed and Web of Science, was performed according to the PRISMA statement. The search period was between 15 June 2023 and 30 June 2023. The Cochrane risk of bias tool was used to analyse the quality of the selected studies.

RESULTS

A total of 11 studies were included in this systematic review. Unifying the rebound effects of all myopia control treatments, the mean rebound effect for axial length (AL) and spherical equivalent refraction (SER) were 0.10 ± 0.07 mm [-0.02 to 0.22] and -0.27 ± 0.2 D [-0.71 to -0.03] after 10.2 ± 7.4 months of washout, respectively. In addition, spectacles with highly aspherical lenslets or defocus incorporated multiple segments technology, soft multifocal contact lenses and orthokeratology showed lower rebound effects compared with atropine and low-level light therapy, with a mean rebound effect for AL and SER of 0.04 ± 0.04 mm [0 to 0.08] and -0.13 ± 0.07 D [-0.05 to -0.2], respectively.

CONCLUSIONS

It appears that the different treatments for myopia control produce a rebound effect after their cessation. Specifically, optical treatments seem to produce less rebound effect than pharmacological or light therapies. However, more studies are required to confirm these results.

Exploring the impact of optical corrections on visual functions in myopia control-a scoping review

PURPOSE

Myopia is controlled optically with peripheral defocus spectacles, multifocal contact lenses, or orthokeratology lenses. However, it is unknown which optical correction will improve visual performance. This scoping review aimed to identify and summarize studies on various visual functions using optical corrections for myopia control.

METHODS

To develop the search strategy, population (Myopia), concept (visual performance), and context (unrestricted race/region) were used. PubMed, SCOPUS, Cochrane Library, and Web of Science databases were searched using the keywords myopia, contrast sensitivity, high and low contrast visual acuity, stereopsis, and optical correction of myopia control. This scoping review protocol was registered in the Open Science Framework registry and followed the framework for scoping review outlined by the Joanna Briggs Institute.

RESULTS

Eight studies (n = 8) met the inclusion criteria and were included in the review. Four were conducted in Europe, two were conducted in China, and one was conducted in Japan and Singapore. Five studies were randomized controlled trials, out of which three used contact lenses and two studies used peripheral defocus spectacles lenses. Studies ranged from one day to 2 years. Three studies that used orthokeratology lenses were prospective study designs. Among the studies that used orthokeratology lenses and contact lenses, two studies measured the contrast sensitivity function with CSV1000 (Vector Vision) under mesopic and photopic conditions, with and without glare. Two studies measured the central and peripheral contrast sensitivity using psychophysics experiments. High and low contrast visual acuity was measured using the Freiburg Vision Test (n = 1) and ETDRS charts (n = 3), and stereopsis was assessed using a random dot stereogram (n = 1). The studies showed a reduction in central and peripheral contrast sensitivity function and low contrast acuity when treated with multifocal contact lenses, orthokeratology lenses, and peripheral defocus lenses compared with single-vision lenses.

CONCLUSION

This scoping review found a reduction in central and peripheral contrast sensitivity function, as well as low contrast visual acuity when using various optical corrections for myopia control, while high-contrast visual acuity remained the same. The impact of visual functions may not influence the effectiveness of myopia control. Eye care practitioners should provide awareness to the parent and patient population about the potential visual impact of recent designs for optical corrections of myopia control.

Comparison of visual performance and image quality between a myopia-control contact lens and a single-vision contact lens

OBJECTIVE

This study aimed to evaluate the visual performance and image quality of concentric dual-focus-designed contact lenses (CLs) compared with single-vision CLs in myopic Chinese people.

METHODS

Twenty myopic volunteers aged between 18 and 26 years were recruited at a university eye hospital to wear both defocus-incorporated soft contact (DISC) lenses and single-vision CLs for 1 week in random order. High- and low-contrast visual acuity (VA), contrast sensitivity (CS), ocular higher-order aberrations (HOA), Strehl ratio and the Quality of Vision (QoV) questionnaire were assessed with each type of CL at weekly follow-up.

RESULTS

Distance VA was not affected by DISC lenses compared to single-vision CLs in either high (p = 0.414) or low contrast (p = 0.431). However, there was a significant reduction in low-contrast near VA with DISC lenses compared with single-vision CLs (p = 0.011). The differences of CS between DISC lenses and single-vision CLs were significantly associated with lighting conditions and spatial frequencies (F = 128.81, P < 0.001). Compared with single-vision CLs, wavefront aberrations of DISC lenses were significantly increased in total HOA, trefoil, and spherical aberrations for either 3.0 mm or 6.0 mm pupil size. The Strehl ratio wearing DISC lenses reduced significantly compared to the single-vision CLs (p < 0.001) at a pupil diameter of 6.0 mm. QoV scores were higher overall (p = 0.026) and frequency (p = 0.019) with DISC lenses than with single-vision CLs, indicating poorer visual performance.

CONCLUSION

DISC lenses provide satisfactory distance VA. However, the higher scores of the QoV questionnaire with DISC lenses may be related to decreased CS at medium or high spatial frequencies and increased higher-order aberrations.

Centration assessment of an extended depth of focus contact lens for myopic progression control

PURPOSE

To evaluate the accuracy and the inter and intra-observer reliability of the centration assessment of extended depth of focus (EDOF) contact lenses (CL) using corneal topography.

METHOD

EDOF soft CLs (Mylo, Mark'Ennovy) were fitted on thirty-three myopic students (25 females), aged 19-28 years (22.7 ± 2.0 years). For any EDOF CL, a topography over the CL and a slit lamp (SL) digital picture were taken in random order. For the topographic images, the position of the EDOF CL centre, with respect to the pupil centre, was detected by two different practitioners (one newly graduated and one with more than 20 years of clinical experience respectively) and repeated after 15 days. This measurement was compared to the one taken through the SL, considered as the gold standard, and assessed using the instrument software.

RESULTS

EDOF CLs resulted decentred inferiorly and temporally ranging, in the case of slit lamp assessment, between -0.27 ± 0.19 and 0.22 ± 0.23 mm horizontally and between -0.12 ± 0.31 and -0.17 ± 0.34 mm vertically, for the right and left eye respectively. The accuracy of the topographic assessment in determining EDOF CL centration was found to be very good compared to the SL assessment. No differences were found for the left eye, whereas in the right eye, a less temporally decentred position of the CL was detected by the topographical method (p < 0.05). However, this difference appeared clinically negligible (0.14 ± 0.22 mm). Inter-observer reliability (the differences between the two practitioners in assessing the EDOF centre) resulted significant only for the vertical coordinates of the centre position (p < 0.05). Concerning intra-observer reliability, better coefficient of precision and reliability between measurements within the same session were achieved by the more experienced practitioner, as well as a better level of the intraclass correlation coefficient in test-retest.

CONCLUSION

The centration of the EDOF CL investigated in this study can be accurately detected by a corneal topography performed over CLs. Inter-observer reliability resulted good whereas the intra-observer reliability resulted partially affected by the level of clinical experience of the practitioner.

Visual performance with multifocal corneal gas-permeable contact lenses in young adults: A pilot study

OBJECTIVES

To evaluate the performance of four experimental multifocal gas permeable contact lens (MFGPCL) designs and their impact on visual function in young adults.

METHODS

Seventeen young adults (age, 23.17 ± 4.48 years) enrolled in the study. Each participant was randomly assigned to wear two of four MFGPCL designs. They wore the first type of the assigned lens binocularly for one week and, after one week of washout period, wore another design on both eyes for another week. The four MFGPCL designs were as follows: design A (distance zone [DZ] 1.5 mm / add 3.0 D), B (DZ 1.5 mm / add 1.5 D), C (DZ 3.0 mm / add 3.0 D), and D (DZ 3.0 mm / add 1.5 D). Baseline visual acuity, contrast sensitivity function, and accommodation data were collected at baseline and repeated after one week of MFGPCL daily wear.

RESULTS

Distance and near visual acuities were not significant affected with the four MFGPCL designs. Contrast sensitivity was significantly lower in design A across all measured spatial frequencies (p < 0.05), with no significant impact from other designs on all frequencies. No significant effect was observed on accommodation measured at 33 cm (p > 0.05).

CONCLUSIONS

Three of the investigated MFGPCL designs preserve satisfactory visual performance. Lens design A incorporated with higher add and smaller center zone diameter had a stronger impact on the visual performance.

Short-term tear film stability, optical quality and visual performance in two dual-focus contact lenses for myopia control with different optical designs

Purpose

To assess and compare short‐term visual and optical quality and tear film stability between two dual‐focus (DF) prototype myopia control contact lenses (CLs) having different inner zone diameters.

Methods

Twenty‐eight myopic subjects were included in this randomised, double‐masked crossover study. Refraction, best‐corrected visual acuity (VA) and tear film stability were measured at baseline (i.e., when uncorrected). Subjects were then binocularly fitted with the DF CLs, with only the sensorial dominant eye being assessed. Lenses were of the same material and had inner zone diameters of either 2.1 mm (S design) or 4.0 mm (M design). Visual and physical short‐term lens comfort, over‐refraction, best‐corrected VA, stereopsis at 40 cm, best‐corrected photopic and mesopic contrast sensitivity (CS), size and shape of light disturbance (LD), wavefront aberrations, subjective quality of vision (QoV Questionnaire) and tear film stability were measured for each lens.

Results

Both CL designs decreased tear film stability compared with baseline (p < 0.05). VA and photopic CS were within normal values for the subjects' age with each CL. When comparing lenses, the M design promoted better photopic CS for the 18 cycles per degree spatial frequency (p < 0.001) and better LD (p < 0.02). However, higher‐order aberrations were improved with the S design (p = 0.02). No significant difference between the two CLs was found for QoV scores and tear film stability.

Conclusions

Both DF CLs provided acceptable visual performance under photopic conditions. The 4.0 mm inner zone gave better contrast sensitivity at high frequencies and lower light disturbance, while the 2.1 mm central diameter induced fewer higher‐order aberrations for a 5 mm pupil diameter. Both CLs produced the same subjective visual short‐term lens comfort.

The influence of contact lenses with different optical designs on the binocular vision and visual behavior of young adults

Theoretically, contact lenses change the accommodation and vergence demands of the eyes and directly or indirectly influence binocular vision. The purpose of this study was to investigate the influence of different optical designs of contact lenses on binocular vision and visual behavior among young adults. In this randomized, single-blinded experimental study, visual behavioral performance (VBP) and Ocular Surface Disease Index questionnaires were used for preliminary screening. Nineteen myopic subjects aged 20-26 years (21.59 ± 1.40 years) participated in the study. Baseline values for subjective refraction and binocular visual functions were evaluated. All the subjects were randomly grouped to wear different optical designs of single-vision, progressive, and bifocal contact lenses. Eye examinations were performed on the first day (CL baseline), 2nd week, and 4th week of wearing the lenses. In addition, subjects completed the VBP and visual quality questionnaire again at the end of the examination. Single-vision contact lenses (Lens 1) increased accommodative lag, negative relative accommodation, and distant and near vergence; however, vergence facilities, accommodative facilities, heterophoria, and the comfort and posture balance dimensions in the VBP questionnaire were improved. Progressive contact lenses (Lens 2) reduced the lag of accommodation and near vergence; in addition, vergence facilities and accommodative facilities were also improved. Bifocal contact lenses (Lens 3) affected negative and positive relative accommodation, but vergence facilities and accommodative facilities also progressed. Furthermore, both progressive (Lens 2) and bifocal (Lens 3) contact lenses enhanced overall visual behavioral performance. In terms of visual quality, single-vision contact lenses (Lens 1) were the most comfortable, progressive and bifocal contact lenses reduced distant visual acuity and stability, progressive contact lenses (Lens 2) had more complaints about halos at night, and bifocal contact lens (Lens 3) users were more likely to have double vision. Compared with single-vision contact lenses, progressive and bifocal contact lenses relaxed accommodation, reduced the lag of accommodation, and improved visual behavioral performance. Although the vergence function showed a significant change, it did not show worse trends when wearing contact lenses. Contact lenses with different optical designs have a great influence on binocular vision and visual behavioral performance.

Contrast Sensitivity with Center-distance Multifocal Soft Contact Lenses

SIGNIFICANCE

The contrast sensitivity (CS) function provides a more detailed assessment of vision than visual acuity. It was found that center-distance multifocal contact lens designs that are increasingly being prescribed for myopia control reduce distance photopic and mesopic CS in nonpresbyopic patients across a range of spatial frequencies.

PURPOSE

This study aimed to determine the effect of center-distance multifocal soft contact lenses (MFCLs) on CS under photopic and mesopic conditions in nonpresbyopic patients.

METHODS

Twenty-five myopic, nonpresbyopic adults were fitted binocularly with three lenses: Biofinity single vision contact lens (SVCL), Biofinity Multifocal D +2.50 add, and NaturalVue Multifocal in random order. Contrast sensitivity was measured at distance (4 m) under photopic and mesopic conditions and at near under photopic conditions. Log CS by spatial frequency and area under the log contrast sensitivity function (AULCSF) were analyzed between lenses.

RESULTS

Distance photopic CS at each spatial frequency was higher with the SVCL than the MFCLs (P < .001), but there was no difference between the MFCLs (P = .71). Distance mesopic CS from 1.5 to 12 cycles per degree (cpd) was higher with the SVCL than the MFCLs (all P < .02); however, at 18 cpd, there was no difference in CS between NaturalVue and the SVCL (P = .76), possibly because of spurious resolution. Photopic AULCSF for the SVCL was roughly 10% greater than both MFCLs. Contrast sensitivity at near was generally similar between lenses, only slightly lower with the NaturalVue at 11 and 15.5 cpd, but AULCSF at near was not different between lenses (P > .05).

CONCLUSIONS

Multifocal contact lenses reduce distance contrast sensitivity under both photopic and mesopic conditions. There is no clinically significant difference in near CS among all three lenses. These data show that MFCLs have effects on vision that are not captured by standard high-contrast visual acuity testing.

Changes in accommodation and behavioural performance with a contact lens for myopia management: A comparison between a dual-focus and a single-vision soft contact lens

Introduction

Dual‐focus soft contact lenses for myopia management have demonstrated to be an effective strategy to reduce myopia progression. However, this optical design has been shown to alter visual quality and accommodative function. The aim of this study was to examine the accommodative and behavioural performance during the execution of a psychomotor vigilance task (PVT) while wearing dual‐focus and single‐vision soft contact lenses.

Methods

The steady‐state accommodative response was recorded with the WAM‐5500 binocular open‐field autorefractor during the execution of a 10‐min PVT at 50 cm either with the dual‐focus (MiSight 1‐day) or single‐vision (Proclear 1‐day) soft contact lenses, using a sample of 23 healthy young adults. Each experimental session was performed on two different days in a counterbalanced order.

Results

A greater lag of accommodation, variability of accommodation and reaction time was found while wearing dual‐focus in comparison with single‐vision soft contact lenses (mean differences during the 10‐min PVT were 0.58 ± 0.81 D, p < 0.001; 0.31 ± 0.17 D, p < 0.001 and 15.22 ± 20.93 ms, p = 0.002, respectively). Also, a time‐on‐task effect was found for the variability of accommodation and reaction time (p = 0.001 and p < 0.001, respectively), observing higher values over time. However, the lag of accommodation did not change significantly as a function of time‐on‐task (p = 0.33).

Conclusion

Dual‐focus soft contact lens wear influences the steady‐state accommodative response and behavioural performance during the execution of a visual vigilance task in the short‐term. Eye care practitioners should be aware of these effects when prescribing these lenses for myopia management, and provide specific recommendations according to the individual visual needs.

Short-Term Effect of Wearing of Extended Depth-of-Focus Contact Lenses in Myopic Children: A Pilot Study

This pseudo-experimental, prospective, and longitudinal pilot study was conducted to characterize the optical and visual changes occurring in the short-term wear of a hydrophilic contact lens (CL) based on extended focus technology (EDOF). A total of 30 eyes of 15 children (age, 6–16 years) were fitted with the EDOF CL Mylo (Mark’ennovy Care SL), performing an exhaustive follow-up for one month evaluating changes in visual acuity (VA), accommodation, binocularity, ocular aberrometry, visual quality, pupillometry, keratometry and biometry. Far and near VA with the CL improved progressively (p < 0.001), obtaining mean final binocular values of −0.08 ± 0.01 and −0.07 ± 0.01 LogMAR, respectively. There was a mean reduction in the accommodative LAG of 0.30 D (p < 0.001), without associated alterations in the magnitude of the phoria and fusional vergences (p ≥ 0.066). A controlled but statistically significant increase (p ≤ 0.005) of ocular high order aberration (HOA) root mean square (RMS), primary coma RMS, primary spherical aberration Zernike term and secondary astigmatism RMS was found with the CL wear. In conclusion, the EDOF CL evaluated provides adequate visual acuity and quality, with associated increased of several HOAs and a trend to reduction in the accommodative LAG that should be confirmed in future studies.

Influence of Lenslet Configuration on Short-Term Visual Performance in Myopia Control Spectacle Lenses

Purpose: This study aimed to evaluate short-term visual performance and optical quality of three different lenslet configurations on myopia control spectacle lenses.

Materials and Methods: This study utilized a cross-over design. Distance visual acuity (VA) was measured in 50 myopic children; contrast sensitivity (CS) was measured in 36 myopic children. For each test, four spectacle lenses were evaluated in a random order: single-vision lens (SVL), lens with concentric rings of highly aspherical lenslets (HAL), lens with concentric rings of slightly aspherical lenslets (SAL), and lens with honeycomb configuration of spherical lenslets (HC). The modulation transfer function (MTF) and MTF area (MTFa) were used to determine optical quality. All tests were performed monocularly on the right eye with full correction.

Results: HAL and SAL had larger MTFa than HC. VA in lenses with lenslets was significantly reduced compared to SVL (all p < 0.01). The reduction in VA was worse with HC than with SAL (p = 0.02) and HAL (p = 0.03); no effect of lenslet asphericity was found (p > 0.05). VA changes induced by lenslets showed no correlation with spherical equivalent refraction (all p > 0.05) and were weakly positively associated with age for SAL (r = 0.36, p = 0.01) and HC (r = 0.31, p = 0.03), but not for HAL (p = 0.30). The area under the log contrast sensitivity function (AULCSF) decreased with HAL and HC (all p < 0.001) in all illumination levels, and AULCSF with HAL was higher than that with HC in a photopic condition (1.17 ± 0.10 vs. 1.10 ± 0.13, p = 0.0004). The presence of lenslets did not affect CS at 3 cycles per degree (cpd) (p = 0.80). At 6 to 18 cpd, CS was significantly reduced by HAL and HC (all p < 0.05), but not SAL (p > 0.05) compared to SVL. At high spatial frequencies (>12 cpd) both SAL and HAL reduced CS significantly less than HC (all p < 0.01).

Conclusion: Short-term visual performance was minimally impaired by looking through the lenslet structure of myopia control spectacle lenses. Concentric rings with aspherical lenslets had a significantly lower impact on both VA and CS than honeycomb configuration with spherical lenslets.

The Effects of 0.01% Atropine on Adult Myopes' Contrast Sensitivity

PURPOSE

Atropine at a low concentration is considered a safe and effective treatment to mitigate myopia progression. However, the potential unwanted side effects of administering atropine at a low dose on visual functions other than best corrected visual acuity has not been investigated. In this study, we investigate the short-term (12,16, and 20 h) and long-term (1, 2, and 4 weeks) effects of 0.01% atropine (i.e., 0.1 mg/ml) on contrast sensitivity (CS) in patients with myopia.

METHODS

Thirty adults (23.33 ± 2.93 years old) with myopia between -1.00 and -6.00 diopters (D), astigmatism of -1.50 D or less, and anisometropia of 1.00 D or less, participated in this prospective, masked, placebo-controlled, randomized study. The participants were randomly assigned to receive 0.01% atropine or polyvinyl alcohol eye drops once nightly to both eyes for four weeks. CS was measured binocularly at baseline and 12, 16, 20 h, 1, 2, and 4 weeks after the first use of the eye drops.

RESULTS

There was no statistically significant differences of CS found between atropine and placebo-controlled groups in both short-term and long-term. There was no statistically significant interaction effect found between the time and group.

CONCLUSION

We demonstrated no significant deleterious effect of 0.01% atropine on adult myopes' CS.

Multifocal Orthokeratology versus Conventional Orthokeratology for Myopia Control: A Paired-Eye Study

We conducted a prospective, paired-eye, investigator masked study in 30 children with myopia (-1.25 D to -4.00 D; age 10 to 14 years) to test the efficacy of a novel multifocal orthokeratology (MOK) lens compared to conventional orthokeratology (OK) in slowing axial eye growth. The MOK lens molded a center-distance, multifocal surface onto the anterior cornea, with a concentric treatment zone power of +2.50 D. Children wore an MOK lens in one eye and a conventional OK lens in the fellow eye nightly for 18 months. Eye growth was monitored with non-contact ocular biometry. Over 18 months, MOK-treated eyes showed significantly less axial expansion than OK-treated eyes (axial length change: MOK 0.173 mm less than OK; p < 0.01), and inner axial length (posterior cornea to anterior sclera change: MOK 0.156 mm less than OK, p < 0.01). The reduced elongation was constant across different baseline progression rates (range -0.50 D/year to -2.00 D/year). Visual acuity was less in MOK vs. OK-treated eyes (e.g., at six months, MOK: 0.09 ± 0.01 vs. OK: 0.02 ± 0.01 logMAR; p = 0.01). We conclude that MOK lenses significantly reduce eye growth compared to conventional OK lenses over 18 months.

Evaluating the Effect of Topical Atropine Use for Myopia Control on Intraocular Pressure by Using Machine Learning

Atropine is a common treatment used in children with myopia. However, it probably affects intraocular pressure (IOP) under some conditions. Our research aims to analyze clinical data by using machine learning models to evaluate the effect of 19 important factors on intraocular pressure (IOP) in children with myopia treated with topical atropine. The data is collected on 1545 eyes with spherical equivalent (SE) less than -10.0 diopters (D) treated with atropine for myopia control. Four machine learning models, namely multivariate adaptive regression splines (MARS), classification and regression tree (CART), random forest (RF), and eXtreme gradient boosting (XGBoost), were used. Linear regression (LR) was used for benchmarking. The 10-fold cross-validation method was used to estimate the performance of the five methods. The main outcome measure is that the 19 important factors associated with atropine use that may affect IOP are evaluated using machine learning models. Endpoint IOP at the last visit was set as the target variable. The results show that the top five significant variables, including baseline IOP, recruitment duration, age, total duration and previous cumulative dosage, were identified as most significant for evaluating the effect of atropine use for treating myopia on IOP. We can conclude that the use of machine learning methods to evaluate factors that affect IOP in children with myopia treated with topical atropine is promising. XGBoost is the best predictive model, and baseline IOP is the most accurate predictive factor for endpoint IOP among all machine learning approaches.

Deterioration of contrast sensitivity in eyes with epiphora due to lacrimal passage obstruction

Purpose

Epiphora causes deterioration in contrast sensitivity in some eye diseases. This study was conducted to investigate contrast sensitivity in eyes with epiphora caused by lacrimal passage obstruction.

Methods

This single-center, prospective case series enrolled 57 patients with unilateral lacrimal passage obstruction. The best-corrected visual acuity (BCVA), contrast sensitivity function, and lower tear meniscus of the affected and contralateral unaffected eyes were compared. The area under the log contrast sensitivity function (AULCSF) was calculated.

Results

The BCVA did not significantly differ between the affected and contralateral eyes, while the AULCSF was significantly lower in the affected eyes than that in the contralateral eyes (median 1.35, interquartile range 1.22–1.44 vs. median 1.36, interquartile range 1.28–1.46, P = 0.032). Lower tear meniscus parameters were significantly higher in the affected eyes than those in the contralateral eyes (P < 0.005).

Conclusions

The contrast sensitivity function is significantly diminished in eyes with epiphora caused by lacrimal passage obstruction.