Monica Jong

Myopia, an underrated global challenge to vision: where the current data takes us on myopia control

Myopia is the most frequent cause of distance impairment in the world and is creating an alarming global epidemic with deleterious ramifications for the quality of life and economic health of individuals and nations as a whole. In addition to being immediately disadvantageous, myopia increases the risk of serious disorders such as myopic macular degeneration, retinal detachment, glaucoma, and cataract and is a leading cause of visual impairment and blindness across many countries. The reduction in age of onset of myopia is of great concern since the earlier the onset, the more myopic the individual will become, with all the attendant increased risks of accompanying debilitating eye conditions. The economic burden is great; both in consequences of uncorrected refractive error and also in the provision of devices for correcting visual acuity. Earlier onset of myopia increases the lifetime economic burden related to loss of productivity and independence, leading to a reduced quality of life. Recent data suggest addressing accommodation per se has little direct amelioration of myopia progression. Pharmacological interventions that effect changes in the sclera show promising efficacy, whereas optical interventions based on a myopic shift in the retinal image are proving to effect up to 55% reduction in the rate of progression of myopia. Early contact lens and spectacle interventions that reduce the rate of progression of myopia are able to significantly reduce the burden of myopia. These non-pharmacological interventions show profound promise in reducing the overall associated morbidity of myopia.

Nearly 1 billion myopes at risk of myopia-related sight-threatening conditions by 2050 - time to act now.

In March 2015, the World Health Organization (WHO) and Brien Holden Vision Institute (BHVI), held the WHO-BHVI Global Scientific Meeting on Myopia in Sydney, at the BHVI, located on the campus of the University of New SouthWales. Key scientists, researchers and clinical experts from around the world, supported by the Australian Government Vision CRC program, joined together to address the rapidly increasing prevalence and the visual, social and economic impact of myopia. It was a historic step in placingmyopia on the world health agenda. An important contribution from themeeting was the definition of myopia and high myopia and a description of a potentially blinding retinal condition associated with myopia; myopic macular degeneration (MMD). As a result, future epidemiological surveys will be able to accurately record the number of people who are blind or permanently vision impaired from myopia. This recognition by the WHO will hopefully be the catalyst for increased government engagement with the issue, including greater support for programs for myopia and investment in the development of solutions, enhancing our capacity to reach populations with the timely interventions and treatments this vast problem requires.

Towards better estimates of uncorrected presbyopia

Normal vision depends upon the ability of the ocular lens to change shape, ensuring that light is focused on the most sensitive part of the retina. Anyone living beyond middle age is inevitably affected by presbyopia, an inability to focus on near objects, due to the loss of flexibility of the ocular lens. It is estimated that over half of the one billion people affected globally cannot afford the spectacles needed to correct their eyesight. Most of the people with uncorrected visual impairment live in low- and middle-income countries.1,2

The Adenosine Receptor Antagonist, 7-Methylxanthine, Alters Emmetropizing Responses in Infant Macaques

Purpose Previous studies suggest that the adenosine receptor antagonist, 7-methylxanthine (7-MX), retards myopia progression. Our aim was to determine whether 7-MX alters the compensating refractive changes produced by defocus in rhesus monkeys. Methods Starting at age 3 weeks, monkeys were reared with −3 diopter (D; n = 10; 7-MX −3D/pl) or +3D (n = 6; 7-MX +3D/pl) spectacles over their treated eyes and zero-powered lenses over their fellow eyes. In addition, they were given 100 mg/kg of 7-MX orally twice daily throughout the lens-rearing period (age 147 ± 4 days). Comparison data were obtained from lens-reared controls (−3D/pl, n = 17; +3D/pl, n = 9) and normal monkeys (n = 37) maintained on a standard diet. Refractive status, corneal power, and axial dimensions were assessed biweekly. Results The −3D/pl and +3D/pl lens-reared controls developed compensating myopic (−2.10 ± 1.07 D) and hyperopic anisometropias (+1.86 ± 0.54 D), respectively. While the 7-MX +3D/pl monkeys developed hyperopic anisometropias (+1.79 ± 1.11 D) that were similar to those observed in +3D/pl controls, the 7-MX −3D/pl animals did not consistently exhibit compensating myopia in their treated eyes and were on average isometropic (+0.35 ± 1.96 D). The median refractive errors for both eyes of the 7-MX −3D/pl (+5.47 D and +4.38 D) and 7-MX +3D/pl (+5.28 and +3.84 D) monkeys were significantly more hyperopic than that for normal monkeys (+2.47 D). These 7-MX–induced hyperopic ametropias were associated with shorter vitreous chambers and thicker choroids. Conclusions In primates, 7-MX reduced the axial myopia produced by hyperopic defocus, augmented hyperopic shifts in response to myopic defocus, and induced hyperopia in control eyes. The results suggest that 7-MX has therapeutic potential in efforts to slow myopia progression.

Distribution and Severity of Myopic Maculopathy Among Highly Myopic Eyes

Purpose The purpose of this study was to document the distribution of the severity of myopic maculopathy in a cohort of highly myopic patients and to explore the associated risk factors. Methods A total of 890 Chinese highly myopes aged between 7 and 70 years (median age 19 years) and with spherical refraction -6.00 diopter (D) or worse in both eyes were investigated. All participants underwent detailed ophthalmic examination. Myopic maculopathy was graded into 5 categories according to the International Photographic Classification and Grading System using color fundus photographs: category 0, no myopic retinal lesions, category 1, tessellated fundus only; category 2, diffuse chorioretinal atrophy; category 3, patchy chorioretinal atrophy; category 4, macular atrophy. Category 2 or greater were further classified as clinically significant myopic maculopathy (CSMM). Results Data from 884 of 890 right eyes were available for analysis. The proportions of category 1, category 2, category 3, and category 4 were 20.0% (177 eyes), 20.2% (178 eyes), 2.6% (23 eyes), and 0.2% (2 eyes), respectively. The proportion of CSMM increased with more myopic refraction (odds ratio 1.57; 95% confidence interval: 1.46-1.68), longer axial length (odds ratio 2.97; 95% confidence interval: 2.50-3.53), and older age (40-70 years compared to 12-18 years, odds ratio 6.77; 95% confidence interval: 3.61-12.70). However, there was a higher proportion of CSMM in children aged 7 to 11 years than those aged 12 to 18 years (20.9% vs. 11.0%, P = 0.008). Conclusions Older age, more myopic refraction, and longer axial length were associated with more severe myopic maculopathy. Although CSMM was uncommon among younger participants, children with early-onset high myopia have a disproportionately increased risk.

Tessellated fundus appearance and its association with myopic refractive error

The appearance of tessellated fundus in an eye may act as a marker in identifying visual performance, degree of myopia or risk of progression of myopia in a given eye. A systematic literature search using key words was performed using PubMed, Web of Science and Google Scholar and of the 832 studies identified, 10 full‐length articles, which met the inclusion criteria, were considered for review. The primary outcome measures were association of tessellated fundus with: (i) visual acuity, (ii) refractive error, (iii) axial length, (iv) choroidal thickness and (v) future progression of myopia when compared to either no myopic maculopathy, or more severe myopic maculopathy. There was no significant difference in the visual acuity noted between eyes with normal fundus and tessellated fundus appearance. Compared to eyes with tessellated fundus, eyes with more severe myopic maculopathy had a four‐line decrease in best‐corrected visual acuity, more myopia (mean difference 2.75 D, range 0.28–5.78 D) and a longer axial length (mean difference 2 mm, range 2.29 to 1.71 mm). Eyes with tessellated fundus generally exhibited a significant decrease in choroidal thickness compared to eyes with no maculopathy. In mostly older individuals, eyes with tessellated fundus had a better outcome with respect to visual acuity, degree of myopia and axial length compared to other severe myopic maculopathies, but had a worse outcome for choroidal thickness and degree of myopia, compared to eyes with no myopic maculopathy. The features such as reduced choroidal thickness combined with a predilection to infra‐temporal and parapapillary regions may indicate regions of stress that are prone to more stretching/atrophic changes. This systematic review demonstrated an association of tessellated fundus with visual acuity, refractive error, axial length and choroidal thickness and hence emphasises the documentation of the presence and location of tessellated fundus appearance that may help in predicting the progression of myopia.

Reduced vision in highly myopic eyes without ocular pathology: the ZOC-BHVI high myopia study

The aim was to investigate the relationship of the magnitude of myopia with visual acuity in highly myopic eyes without ocular pathology.

Visual performance of myopia control soft contact lenses in non-presbyopic myopes

Purpose To compare the visual performance of soft contact lenses reported to reduce myopia progression. Methods In a double-blind, randomized, crossover trial, 30 non-presbyopic myopes wore MiSight™, center-distance Proclear® Multifocal (+2.00 D add), and two prototype lenses for 1 week each. High- and low-contrast visual acuities at 6 m, and 70 and 40 cm; stereopsis at 40 cm; accommodative facility at 33 cm; and horizontal phoria at 3 m and 33 cm were measured after 1 week. Subjective performance was assessed on a numeric rating scale for vision clarity, lack of ghosting, vision stability, haloes, overall vision satisfaction, and ocular comfort. Frequency of eye-strain symptoms and willingness to purchase lenses were also reported with categorical responses. Participants reported wearing times (total and visually acceptable). Linear mixed models and chi-square tests were employed in analysis with level of significance set at 5%. Theoretical optical performance of all lenses was assessed with schematic myopic model eyes (−1.00, −3.00, and −6.00 D) by comparing the slope of the edge spread function (ESF), an indicator for optical performance/resolution and the blur patch size of the line spread function, an indicator for contrast, between the lenses. Results Proclear Multifocal and MiSight provided the best distance acuities. However, the prototype lenses were rated significantly higher for many subjective variables, and there were no subjective variables where commercial lenses were rated significantly higher than the prototypes. Theoretical optical performance showed steeper slopes of the ESF and greater blur patch sizes of the LSP with commercial lenses, supporting the clinical findings of better visual acuities but reduced subjective performance. Participants wore prototypes longer and reported their vision acceptable for longer each day compared to MiSight. Both prototypes had the highest willingness-to-purchase rate. Conclusions The prototypes were better tolerated by myopes compared to the commercial soft contact lenses currently used for slowing myopia progression.

Global prevalence of visual impairment associated with myopic macular degeneration and temporal trends from 2000 through 2050: systematic review, meta-analysis and modelling

Purpose We used systematic review and meta-analysis to identify and assimilate evidence quantifying blindness and visual impairment (VI) associated with myopic macular degeneration (MMD), then derived models to predict global patterns. The models were used to estimate the global prevalence of blindness and VI associated with MMD from 2000 to 2050. Methods The systematic review identified 17 papers with prevalence data for MMD VI fitting our inclusion criteria. Data from six papers with age-specific data were scaled to relative age-dependent risk and meta-analysed at VI and blindness levels. We analysed variance in all MMD VI and blindness data as a proportion of high myopia against variables from the place and year of data collection, with a model based on health expenditure providing the best correlation. We used this model to estimate the prevalence and number of people with MMD VI in each country in each decade. Results We included data from 17 studies comprising 137 514 participants. We estimated 10.0 million people had VI from MMD in 2015 (prevalence 0.13%, 95% CI 5.5 to 23.7 million, 0.07% to 0.34%), 3.3 million of whom were blind (0.04%, 1.8 to 7.8 million, 0.03% to 0.10%). We estimate that by 2050, without changing current interventions, VI from MMD will grow to 55.7 million people (0.57%, 29.0 to 119.7 million, 0.33% to 1.11%), 18.5 million of whom will be blind (0.19%, 9.6 to 39.7 million, 0.11% to 0.37%). Conclusion The burden of MMD blindness and VI will rise significantly without efforts to reduce the development and progression of myopia and improve the management of MMD.