Visual Performance of Center-distance Multifocal Contact Lenses Fit Using a Myopia Control Paradigm

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 management contact lens design on accommodative microfluctuations and eye movements during reading

BACKGROUND

Soft contact lenses have been developed and licensed for reducing myopia progression. These lenses have different designs, such as extended depth of focus (EDOF) and dual focus (DF). In this prospective, double-masked, cross-over study, different lens designs were investigated to see whether these had impact on accommodative microfluctuations and eye movements during reading.

METHODS

Participants were fitted with three lenses in a randomised order; a single vision (SV) design (Omafilcon A2; Proclear), a DF design (Omafilcon A2; MiSight), and an EDOF lens design (Etafilcon A; NaturalVue),. Accommodative microfluctuations were measured at 25 cm for at least 60s in each lens, using a Shin-Nippon SRW-5000 autorefractor adapted to continuously record accommodation at 22Hz. Eye movement data was collected with the Thomson Clinical Eye Tracker incorporating a Tobii Eye bar. Eye movements include fixations per row, fixations per minute, mean regressions per row, total number of regressions, and total rightward saccades. Accommodation data was analysed using power spectrum analysis. Differences between the lenses were compared using a related sample two-way Friedman test.

RESULTS

Twenty-three participants (18-29 years) were recruited to take part. The average mean spherical error was -2.65D ± 1.42DS, with an average age of 23.4 ± 3.5 years. No significant difference for accommodative microfluctuations was found. Significant differences were found for fixations per row (P = 0.03), fixations per minute (P = 0.008), mean regressions per row (P = 0.002), and total number of regressions (P = 0.002), but not total rightward saccades (P = 0.10). Post-hoc analysis indicated the EDOF lens results were significantly different from the other lenses, with more regressive eye movements observed.

CONCLUSIONS

Regressive saccades appear to increase when wearing EDOF lens designs, which may impact visual comfort. Further studies in children, over a longer period of adaptation are necessary to assess the potential impact of this finding on daily reading activities in children.

The Effect of Myopic Control between the Dual-Focus Contact Lenses and High-Concentration Atropine in an Asian Population

We aim to investigate the myopic control effect of high-concentration atropine (ATR) and dual-focus contact lenses (DFCLs). A retrospective cohort study was conducted. A total of 182 eyes in 91 individuals who used high-concentration ATR (0.125%) and another 70 eyes in 35 individuals who used DFCLs were enrolled in the ATR and DFCL groups, respectively. The primary outcomes were spherical equivalent refraction (SER) progression and axial length (AXL) elongation. The generalized estimate equation was utilized to yield the adjusted odds ratio (aOR) and 95% confidence interval (CI) of cycloplegic SER progression and AXL elongation between groups. According to the multivariable analysis, the change in cycloplegic SER progression was similar between the DFCL and ATR groups (aOR: 1.305, 95% CI: 0.247-2.515, p = 0.803). The DFCL group demonstrated a numerically higher rate of AXL elongation compared to the ATR group (aOR: 1.530, 95% CI: 0.980-1.894, p = 0.051). In the subgroup analysis, cycloplegic SER progression was insignificant between ATR and DFCL users in different subgroups (all p > 0.05). The DFCL patients with moderate astigmatism and high AXL (both p < 0.001) presented a high risk of AXL elongation. In conclusion, DFCL usage demonstrated similar myopic control of cycloplegic SER and AXL compared to high-concentration ATR, while DFCLs showed lower AXL control, mainly in patients with moderate astigmatism and high AXL.

Quality of life after wearing multifocal contact lenses for myopia control for 2 weeks in the BLINK Study

PURPOSE

To validate Pediatric Refractive Error Profile 2 (PREP2) subscales that can be used to evaluate contact lens wearers and compare vision-specific quality of life measurements between children wearing multifocal and single vision contact lenses for 2 weeks.

METHODS

Two hundred and ninety-four myopic children aged 7-11 years (inclusive) were enrolled in the 3-year, double-masked Bifocal Lenses In Nearsighted Kids (BLINK) Study. Participants completed the PREP2 survey after having worn contact lenses for 2 weeks. The Vision, Symptoms, Activities and Overall PREP2 subscales were used to compare participants' subjective assessment while wearing +1.50 or +2.50 D add multifocal or single vision contact lenses. Rasch analysis was used to validate each subscale and to compare participants' subjective assessment of contact lens wear.

RESULTS

Item fit to the Rasch model was good for all scales, with no individual items having infit mean square statistics outside the recommended range (0.7-1.3). Response category function was acceptable for all subscales, with ordered category thresholds. Measurement precision, assessed by the Rasch person reliability statistic, was less than ideal (≥0.8) for three of the subscales, but met the minimum acceptable standard of 0.5. Scores for the Vision subscale differed by treatment assignment (p = 0.03), indicating that participants with the highest add power reported statistically worse quality of vision, although the difference was only 3.9 units on a scale of 1-100. Girls reported fewer symptoms than boys (p = 0.006), but there were no other differences between boys and girls.

CONCLUSIONS

Rasch analysis demonstrates that the PREP2 survey is a valid instrument for assessing refractive error-specific quality of life. These results suggest that vision-related quality of life is not meaningfully affected by 2 weeks of soft multifocal contact lens wear for 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.

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.

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.

Modelling the refractive and imaging impact of multi-zone lenses utilised for myopia control in children's eyes

PURPOSE

To develop an optical model of a child's eye to reveal the impact of target distance and accommodative behaviour on retinal image quality when fitted with multi-zone lenses.

METHODS

Pupil size, aberration levels and accommodative lag were adjusted for models viewing stimuli at 400, 100, 33 and 20 cm. Distributions of defocus across the pupil and simulated retinal images were obtained. An equivalent 16-point letter was imaged at near viewing distances, while a 0.00 logMAR (6/6) letter was imaged at 400 cm. Multi-zone lenses included those clinically utilised for myopia control (e.g., dual-focus, multi-segmented and aspherical optics).

RESULTS

Viewing distance adjustments to model spherical aberration (SA) and pupil radius resulted in a model eye with wider defocus distributions at closer viewing distances, especially at 20 cm. The increasing negative SA at near reduced the effective add power of dual-focus lenses, reducing the amount of myopic defocus introduced by the centre-distance, 2-zone design. The negative SA at near largely compensated for the high positive SA introduced by the aspheric lens, removing most myopic defocus when viewing at near. A 0.50 D accommodative lag had little impact on the legibility of typical text (16-point) at the closer viewing distances.

CONCLUSIONS

All four multi-zone lenses successfully generated myopic defocus at greater viewing distances, but two failed to introduce significant amounts of myopic defocus at the nearest viewing distance due to the combined effects of pupil miosis and negative SA. Typical 16-point type is easily legible at near even in presence of the multi-zone optics of lenses utilised for myopia control and accommodative lag.

The use of autorefractors using the image-size principle in determining on-axis and off-axis refraction. Part 2: Theoretical study of peripheral refraction with the Grand Seiko AutoRef/Keratometer WAM-5500

PURPOSE

To determine, through simulations, the likely validity of Grand-Seiko autorefractors with annular targets in peripheral refraction.

METHODS

Using a physical model eye, the distance inside the eye to which the Grand Seiko AutoRef/Keratometer WAM-5500 beam was converging and the effective size of its outer diameter at the cornea were determined. Grand-Seiko refraction was calculated from R_x  = (θ + α)/h₁ , where θ is the angle of the ingoing radiation beam, h₁ is the height of the beam at the anterior cornea and α is the angle of the beam emerging from the eye following reflection at the retina. Two eye models were used: a Navarro schematic eye and a Navarro schematic eye with a contact lens having a highly positive aspheric front surface.

RESULTS

The instrument beam was determined to be converging towards the eye to a distance of 24.4 mm behind the corneal vertex, with a 2.46 mm effective size outer diameter of the beam at the anterior cornea. The Grand-Seiko refractions provided accurate estimates of peripheral refraction for the model eyes. The results were closer to Zernike refractions than to Zernike paraxial refraction. Spherical aberration influenced refraction by up to 0.5 D, and peripheral coma had limited influence.

CONCLUSION

Grand-Seiko autorefractors in current use, and having a circular annulus with an ingoing effective outer diameter at the front of the eye of about 2.4 mm, are likely to give valid peripheral refractions.