Five-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 4 Report

PURPOSE

To evaluate (1) the long-term efficacy of low-concentration atropine over 5 years, (2) the proportion of children requiring re-treatment and associated factors, and (3) the efficacy of pro re nata (PRN) re-treatment using 0.05% atropine from years 3 to 5.

DESIGN

Randomized, double-masked extended trial.

PARTICIPANTS

Children 4 to 12 years of age originally from the Low-Concentration Atropine for Myopia Progression (LAMP) study.

METHODS

Children 4 to 12 years of age originally from the LAMP study were followed up for 5 years. During the third year, children in each group originally receiving 0.05%, 0.025%, and 0.01% atropine were randomized to continued treatment and treatment cessation. During years 4 and 5, all continued treatment subgroups were switched to 0.05% atropine for continued treatment, whereas all treatment cessation subgroups followed a PRN re-treatment protocol to resume 0.05% atropine for children with myopic progressions of 0.5 diopter (D) or more over 1 year. Generalized estimating equations were used to compare the changes in spherical equivalent (SE) progression and axial length (AL) elongation among groups.

MAIN OUTCOMES MEASURES

(1) Changes in SE and AL in different groups over 5 years, (2) the proportion of children who needed re-treatment, and (3) changes in SE and AL in the continued treatment and PRN re-treatment groups from years 3 to 5.

RESULTS

Two hundred seventy (82.8%) of 326 children (82.5%) from the third year completed 5 years of follow-up. Over 5 years, the cumulative mean SE progressions were -1.34 ± 1.40 D, -1.97 ± 1.03 D, and -2.34 ± 1.71 D for the continued treatment groups with initial 0.05%, 0.025%, and 0.01% atropine, respectively (P = 0.02). Similar trends were observed in AL elongation (P = 0.01). Among the PRN re-treatment group, 87.9% of children (94/107) needed re-treatment. The proportion of re-treatment across all studied concentrations was similar (P = 0.76). The SE progressions for continued treatment and PRN re-treatment groups from years 3 to 5 were -0.97 ± 0.82 D and -1.00 ± 0.74 D (P = 0.55) and the AL elongations were 0.51 ± 0.34 mm and 0.49 ± 0.32 mm (P = 0.84), respectively.

CONCLUSIONS

Over 5 years, the continued 0.05% atropine treatment demonstrated good efficacy for myopia control. Most children needed to restart treatment after atropine cessation at year 3. Restarted treatment with 0.05% atropine achieved similar efficacy as continued treatment. Children should be considered for re-treatment if myopia progresses after treatment cessation.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Prevalence of Myopia in Children Before, During, and After COVID-19 Restrictions in Hong Kong

Importance

Childhood myopia increased during the COVID-19 pandemic. Limited evidence exists about whether myopia development was reversed or worsened after the lockdown.

Objective

To determine the prevalence of myopia and its associated factors before, during, and after COVID-19 restrictions.

Design, Setting, and Participants

This population-based, repeated cross-sectional study evaluated children aged 6 to 8 years from the Hong Kong Children Eye Study between 2015 and 2021 in 3 cohorts: before COVID-19 (2015-2019), during COVID-19 restrictions (2020), and after COVID-19 restrictions were lifted (2021).

Exposures

All the children received ocular examinations, including cycloplegic autorefraction and axial length. Data about the children's lifestyle, including time spent outdoors, near-work time, and screen time, were collected from a standardized questionnaire.

Main Outcomes and Measures

The main outcomes were the prevalence of myopia, mean spherical equivalent refraction, axial length, changes in lifestyle, and the associated factors over 7 years. Data were analyzed using descriptive statistics, logistic regression, and generalized estimating equations.

Results

Of 20 527 children (mean [SD] age, 7.33 [0.89] years; 52.8% boys and 47.2% girls), myopia prevalence was stable from 2015 to 2019 (23.5%-24.9%; P = .90) but increased to 28.8% (P < .001) in 2020 and 36.2% (P < .001) in 2021. The mean (SD) time spent outdoors was much lower in 2020 (0.85 [0.53] h/d; P < .001) and 2021 (1.26 [0.48] h/d; P < .001) compared with pre-COVID-19 levels (1.40 [0.47]-1.46 [0.65] h/d). The trend was reversed for total near-work time and screen time. High myopia prevalence was associated with the COVID-19 pandemic (odds ratio [OR], 1.40; 95% CI, 1.28-1.54; P < .001), younger age (OR, 1.84; 95% CI, 1.76-1.93; P < .001), male sex (OR, 1.11; 95% CI, 1.03-1.21; P = .007), lower family income (OR, 1.05; 95% CI, 1.00-1.09; P = .04), and parental myopia (OR, 1.61; 95% CI, 1.52-1.70; P < .001). During the pandemic, mean (SD) near-work and screen times in children from lower-income families were 5.16 (2.05) h/d and 3.44 (1.97) h/d, more than from higher-income families (4.83 [1.85] and 2.90 [1.61] h/d, respectively).

Conclusions and Relevance

The findings of this cross-sectional study revealed that after COVID-19 restrictions were lifted in Hong Kong, myopia prevalence among children was higher than before the pandemic, and lifestyle did not return to pre-COVID-19 levels. Younger children and those from low-income families were at a higher risk of myopia development during the pandemic, suggesting that collective efforts for myopia control should be advocated for these groups.

Effect of Low-Concentration Atropine Eyedrops vs Placebo on Myopia Incidence in Children: The LAMP2 Randomized Clinical Trial

Importance

Early onset of myopia is associated with high myopia later in life, and myopia is irreversible once developed.

Objective

To evaluate the efficacy of low-concentration atropine eyedrops at 0.05% and 0.01% concentration for delaying the onset of myopia.

Design, Setting, and Participants

This randomized, placebo-controlled, double-masked trial conducted at the Chinese University of Hong Kong Eye Centre enrolled 474 nonmyopic children aged 4 through 9 years with cycloplegic spherical equivalent between +1.00 D to 0.00 D and astigmatism less than -1.00 D. The first recruited participant started treatment on July 11, 2017, and the last participant was enrolled on June 4, 2020; the date of the final follow-up session was June 4, 2022.

Interventions

Participants were assigned at random to the 0.05% atropine (n = 160), 0.01% atropine (n = 159), and placebo (n = 155) groups and had eyedrops applied once nightly in both eyes over 2 years.

Main Outcomes and Measures

The primary outcomes were the 2-year cumulative incidence rate of myopia (cycloplegic spherical equivalent of at least -0.50 D in either eye) and the percentage of participants with fast myopic shift (spherical equivalent myopic shift of at least 1.00 D).

Results

Of the 474 randomized patients (mean age, 6.8 years; 50% female), 353 (74.5%) completed the trial. The 2-year cumulative incidence of myopia in the 0.05% atropine, 0.01% atropine, and placebo groups were 28.4% (33/116), 45.9% (56/122), and 53.0% (61/115), respectively, and the percentages of participants with fast myopic shift at 2 years were 25.0%, 45.1%, and 53.9%. Compared with the placebo group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 24.6% [95% CI, 12.0%-36.4%]) and percentage of patients with fast myopic shift (difference, 28.9% [95% CI, 16.5%-40.5%]). Compared with the 0.01% atropine group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 17.5% [95% CI, 5.2%-29.2%]) and percentage of patients with fast myopic shift (difference, 20.1% [95% CI, 8.0%-31.6%]). The 0.01% atropine and placebo groups were not significantly different in 2-year cumulative myopia incidence or percentage of patients with fast myopic shift. Photophobia was the most common adverse event and was reported by 12.9% of participants in the 0.05% atropine group, 18.9% in the 0.01% atropine group, and 12.2% in the placebo group in the second year.

Conclusions and Relevance

Among children aged 4 to 9 years without myopia, nightly use of 0.05% atropine eyedrops compared with placebo resulted in a significantly lower incidence of myopia and lower percentage of participants with fast myopic shift at 2 years. There was no significant difference between 0.01% atropine and placebo. Further research is needed to replicate the findings, to understand whether this represents a delay or prevention of myopia, and to assess longer-term safety.

Trial Registration

Chinese Clinical Trial Registry: ChiCTR-IPR-15006883.

Association of Secondhand Smoking Exposure With Choroidal Thinning in Children Aged 6 to 8 Years: The Hong Kong Children Eye Study

Importance

Secondhand smoking is a risk to adult ocular health, but its effect on children's ocular development is not known.

Objective

To assess the association between choroidal thickness and secondhand smoking exposure in children.

Design, Setting, and Participants

Children aged 6 to 8 years were consecutively recruited from January 2016 to July 2017 from the population-based Hong Kong Children Eye Study at the Chinese University of Hong Kong Eye Centre. All participants underwent detailed ophthalmic investigations. Choroidal thickness was measured by swept-source optical coherence tomography, with built-in software that automatically segmented the choroid layer to analyze its terrain imagery. History of secondhand smoking was obtained from a questionnaire. Multiple linear regression analyses were performed to assess the correlation between choroidal thickness and secondhand exposure when controlling for confounding factors. Analysis began July 2018 and ended in April 2019.

Main Outcomes and Measurements

The association between children's choroidal thickness and their exposure to secondhand smoking.

Results

Of 1400 children, 941 (67.2%) had no exposure to secondhand smoking, and 459 (32.8%) had exposure to secondhand smoking. The mean (SD) age was 7.65 (1.09) years for children in the nonexposure group and 7.54 (1.11) years for children in the exposure group. After adjustment for age, sex, body mass index, axial length, and birth weight, exposure to secondhand smoking was associated with a thinner choroid by 8.3 μm in the central subfield, 7.2 μm in the inner inferior, 6.4 μm in the outer inferior, 6.4 μm in the inner temporal, and 7.3 μm in the outer temporal. Choroidal thinning with also associated with increased number of family smokers and increased quantity of secondhand smoking. An increase of 1 family smoker was associated with choroidal thinning by 7.86 μm in the central subfield, 4.51 μm in the outer superior, 6.23 μm in the inner inferior, 5.59 μm in the outer inferior, 6.06 μm in the inner nasal, and 6.55 μm in the outer nasal. An increase of exposure to 1 secondhand cigarette smoke per day was associated with choroidal thinning by 0.54 μm in the central subfield, 0.42 μm in the inner temporal, and 0.47 μm in the outer temporal.

Conclusions and Relevance

This investigation showed that exposure to secondhand smoking in children was associated with choroidal thinning along with a dose-dependent effect. These results support evidence regarding the potential hazards of secondhand smoking to children.