The influence of age, refractive error, visual demand and lighting conditions on accommodative ability in Malay children and adults

Baseline Accommodation and Binocular Vision Measures in Malay Schoolchildren Enrolled in the Myopia Control Study Using Spectacle Lenses in Kuala Lumpur

Myopia control lenses have been shown to modify visual function; however, it is arguable if these changes are short-term or long-term. We investigated the changes in accommodative behaviour and binocular vision functions of Malay myopic children who participated in a myopia control trial utilising spectacle lenses (n = 40). This article presents baseline accommodation and binocular vision measurements. The mean (± SD) age, spherical equivalent measured by cycloplegic autorefraction, and axial length (AL) for the right eyes were 10.00 ± 1.47 years, -3.02 ± 1.20 D, and 24.42 ± 0.93 mm, respectively. All participants had good distance and near visual acuities with high-contrast charts (100%), which were significantly better than low-contrast charts (10%) (p < 0.001). The mean (± SD) accommodative lag at baseline was 1.14 ± 0.35 D, while monocular and binocular accommodative amplitudes were 15.35 ± 2.07 D and 16.82 ± 2.27 D, respectively. Malay schoolchildren in this study were more esophoric at near compared to distance, with an accommodative-convergence over accommodation (AC/A) ratio of 5.64 ± 0.66 ∆/D. A higher degree of myopia was found to be associated with a longer AL (r = -0.49, p < 0.05) and higher esophoria at near (r = -0.46, p < 0.05). These baseline measures are consistent with data from other studies showing that myopic children have a high accommodative lag, an elevated AC/A ratio, a longer AL, and are more esophoric at near. The measures reported herein will serve as a basis for examining changes that occur within 12 months of wearing myopia control spectacle lenses.

Immediate Effects of Vergence Exercises Using Automatic Dual Rotational Risley Prisms on Accommodative Lag and Facility

INTRODUCTION

This study evaluated novel automatic dual rotational Risley prisms (ADRRPs) as a vergence exercise tool for patients with myopia to improve accommodative lag and accommodative facility.

METHODS

Participants with myopia aged 20-24 years were recruited. After vergence exercises with prisms (treatment group) or plano lenses (control group) using ADRRPs for 10 min, measurements were taken using an open-field autorefractor (Grand Seiko WAM-5500) at viewing distances of 0.4 m and 6.0 m. We measured accommodative facility using a ± 2.00 D accommodative flipper.

RESULTS

A total of 56 participants (treatment group, 39; control group, 17) performed vergence exercises using ADRRPs. Participants in the treatment group showed improvements in accommodative lag at a 0.4 m viewing distance, with measurements of 0.57 D (right eye; OD) and 0.53 D (left eye; OS) and 0.21 D (OD) and 0.27 D (OS) before and after the exercises, respectively (p < 0.001). Over-refractions using an open-field autorefractor with spherical equivalent contact lenses at a 6.0 m viewing distance were - 0.01 ± 0.30 D (OD) and 0.03 ± 0.34 D (OS) and 0.15 ± 0.32 D (OD) and 0.19 ± 0.28 D (OS) before and after the exercises, respectively (difference + 0.16 D; p < 0.001). Accommodative facility values before and after exercises were 14.88 ± 3.36 and 15.59 ± 3.60 cpm, respectively (p < 0.01). No significant differences in accommodative lag, relaxation, and accommodative facility before and after exercise were observed in the control group.

CONCLUSIONS

Using ADRRPs in vergence exercises can improve accommodative lag, accommodative facility, and accommodative relaxation in adults with myopia. Further research to evaluate persistent and long-term effects is needed.

Prevalence of Accommodative Microfluctuations in Eyes after Cataract Surgery

BACKGROUND

We aimed to evaluate the existence of accommodative microfluctuations in eyes after cataract surgery.

METHODS

This retrospective observational cohort study included 1160 eyes of 713 patients (mean age: 72.5 ± 8.3 years) who underwent phacoemulsification, intraocular lens insertion, and an evaluation of accommodative microfluctuations with an autorefractometer. Patients with posterior segment disorders resulting in visual acuity impairment and those with unavailable medical information were excluded. High-frequency components (HFCs), between 1.0-2.3 Hz, based on fast Fourier transform analysis of the accommodative microfluctuation data were examined at postoperative 2-3 (2 M) and 6 months (6 M). The relationships between the HFCs and patient age, manifest refraction, and axial length were analyzed.

RESULTS

Increased HFC values (>65) were observed at a constant rate after cataract surgery, with prevalence rates of 33.4% at 2 M and 34.7% at 6 M. Postoperatively, at 2 M, increased HFC values were significantly more common for eyes with axial length ≥26 mm than for those with axial length <26 mm (p = 0.0056). However, they were not significantly correlated to age or postoperative manifest refraction.

CONCLUSIONS

At 2 M postoperatively, increased HFC values presented more frequently in eyes with a greater axial length; hence, the precise detection and understanding of postoperative accommodative spasms in high myopia patients is important.

Reduction in Accommodative Response of Schoolchildren by a Double-Mirror System

PURPOSE

This study first proposed the application of a double-mirror system (DMS) to extend viewing distance and investigate the accommodative response of schoolchildren under a DMS.

METHOD

Fifty-seven subjects aged between 7 and 12 years old were recruited in this study, and the experiment was divided into two stages. The first stage consisted of a case history inquiry, a refraction state, and a visual function examination. In the second stage, the subjects gazed at an object at distances of 0.4 m, 2.285 m, and through a DMS, respectively, and their accommodative responses were measured using an open-field autorefractor.

RESULTS

There was no significant difference in the schoolchildren's accommodative response between subjects gazing at an object at 2.285 m (0.14 ± 0.35 D, p > 0.05) and those gazing at it through a DMS (0.20 ± 0.35 D). However, their accommodative response showed a significant difference between subjects gazing at an object at 0.4 m and 2.285 m and those gazing at it at 0.4 m and through a DMS.

CONCLUSION

In this experiment, the results of the children's accommodative response measured at 2.285 m or through a DMS are very similar. The viewing distance can be extended by a DMS, resulting in accommodative relaxation. This result may have potential applications in myopia control.

Lag of accommodation predicts clinically significant change of spherical equivalents after cycloplegia

AIM

To evaluate related factors with the change of spherical equivalents (ΔSE) and determine the suitable predictor of clinically significant ΔSE (≥0.50 D) with cyclopentolate hydrochloride on Chinese children.

METHODS

A total of 145 right eyes of 145 children aged 4 to 15y were enrolled. Intraocular pressure, axial length and lag of accommodation (LOA) were assessed before cycloplegia induced by 3 drops of 1% cyclopentolate at 5-minute intervals. SE was measured before and 1h after the first drop of cyclopentolate. ΔSE was compared between different gender groups and among refractive groups. Multivariate linear regression analysis was performed to find related factors with ΔSE. ROC analysis was used to figure out the suitable predictor of clinically significant ΔSE.

RESULTS

For the total 145 eyes, the mean SE reached up to -0.70±1.86 D from -1.30±1.62 D, with the mean ΔSE of 0.60±0.55 D. The mean ΔSE were 0.63±0.55 D and 0.57±0.56 D respectively in the male and female group (P=0.40). The mean ΔSE was significantly different among different refractive groups (P<0.0001), with the ΔSE of hyperopia group (1.12±0.64 D) larger than that of the emmetropia (0.56±0.43 D, P=0.001) and myopia group (0.32±0.28 D, P<0.0001). The ΔSE was correlated with LOA (B=-0.54, P<0.0001), cycloplegic SE (B=0.10, P<0.0001) and age (B=-0.04, P=0.015). ROC curve indicated that LOA predicted clinically significant ΔSE by 82% [area under the curve (AUC)=0.82] alone, while the value was slightly improved to 85% (AUC=0.85) in combination with axial length and 86% (AUC=0.86) in association with axial length as well as age.

CONCLUSION

After cycloplegia with cyclopentolate, the ΔSE decreases with larger LOA, longer axial length and older age. Specifically, LOA plays a more vital role in predicting clinically significant ΔSE.

IMI Accommodation and Binocular Vision in Myopia Development and Progression

The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.

Effect of reading with a mobile phone and text on accommodation in young adults

Purpose

To investigate the effects of reading with mobile phone versus text on accommodation accuracy and near work-induced transient myopia (NITM) and its subsequent decay during near reading in young adults with mild to moderate myopia.

Methods

The refractions of 31 young adults were measured with an open-field autorefractor (WAM-5500, Grand Seiko) for two reading tasks with a mobile phone and text at 33 cm. The mean age of the young adults was 24.35 ± 1.80 years. The baseline refractive aspects were determined clinically with full distance refractive correction in place. The initial NITM and its decay time and accommodative lag were assessed objectively immediately after binocularly viewing a mobile phone or text for 40 min.

Results

The mean ± standard deviation (SD) initial NITM magnitude was greater for reading with text (0.23 ± 0.26 D) than for reading with mobile phone (0.12 ± 0.17 D), but there was no significant difference between the two reading tasks (p = 0.082). The decay time (median, first quartile, and third quartile) was 60 s (16, 154) and 70 s (32, 180) in the phone task and text task groups, respectively. There was also no significant difference in the decay time between the two reading types in general (p = 0.294). The accommodative lags of text tasks and mobile phones tasks were equivalent (1.27 ± 0.52 D vs 1.31 ± 0.64 D, p = 0.792).

Conclusion

There were no significant differences in accommodative lags and the initial NITM and its decay time between reading with a mobile phone and text in young adults.

Repeatability and reproducibility of manifest refraction

PURPOSE

To evaluate the intraexaminer repeatability and the interobserver reproducibility of manifest refraction.

SETTING

Tertiary referral center.

DESIGN

Retrospective study.

METHODS

Patients attending at least 2 preoperative refractions before undergoing subsequent refractive surgery were included. All manifest refractions were performed by 1 of 4 experienced optometrists using an automated phoropter according to a standard protocol. The first manifest refraction was performed after obtaining automated refraction and measuring the spectacles of the patient. The second refraction was typically refined from the first also considering wavefront refraction and tomography/topography.

RESULTS

The latest 2 manifest refractions of 1000 eyes obtained at 2 separate visits showed a mean pairwise absolute difference of 0.16 ± 0.19 diopter (D) (range 0 to 1.38 D) in spherical equivalent (SE). This SD was better than 0.25 D (the minimum measurement increment of refraction itself). The 95% limit of agreement (LoA) was within 0.50 D for sphere, cylinder, and SE. The SD of the astigmatism axis was approximately 10 degrees, and the 95% LoA was within 22 degrees (the difference in axis decreasing significantly with the measured cylinder magnitude). The SD for corrected distance visual acuity (CDVA) was half a Snellen line and the 95% LoA was within 1.5 lines (with increasing deviation with worse vision). There were no clinically meaningful differences in reproducibility (2 optometrists) compared with repeatability (same optometrist) in sphere, axis, and CDVA.

CONCLUSIONS

Reproducibility was 0.16 D irrespective whether refractions were performed by 1 or 2 different optometrists. Obtaining multiple refractions preoperatively might increase the predictability of surgery and decrease the enhancement rate.