The Brien Holden Vision Institute (BHVI) is an Australian nonprofit non-governmental organization with an international focus on eye care research and vision care delivery. Formerly the Institute for Eye Research, in 2010 it was renamed in recognition of co-founder Brien Holden, a 1997 recipient of the Medal of the Order of Australia for his contributions to eye care research.
Our study aimed to compare the efficacy of Myopia Control Spectacles (MCS), including Defocus Incorporated Multiple Segment (DIMS) and Highly Aspherical Lenslets (HAL), and dual-focus contact lenses on myopia progression. This longitudinal, real-world study included myopic children aged 7 to 18 years wearing myopia control optical modalities for at least 12 months between 2020 and 2024, with a group using single-vision lenses included for reference. After matching for age, sex, and baseline refractive error, changes in cycloplegic spherical equivalent of the right eye were assessed at twelve, eighteen, and twenty-four months, including a subgroup of children who showed faster initial progression. The cohort included 425 children using dual-focus contact lenses, 307 using DIMS, 118 using HAL, and 850 using single-vision lenses. At twenty-four months, myopia control was not statistically different between the dual-focus contact lenses and myopia control spectacles group. For the subgroup of progressors, the myopia control groups of children showed median progression of − 0.25 to 0.00D. In this European real-world study on different myopia control optical modalities, both MCS and MCL showed no statistical differences in reduction in myopia progression (for 7 to 12 years old, $$\:{\epsilon\:}^{2}$$=0.01 [95%CI = 0 to 0.07]. These findings should be interpreted with caution, as the study relied on spherical equivalent calculated from optical refraction rather than axial length measurement, thereby restricting its ability to fully assess true myopia progression.
Objective/Purpose In 2020, an estimated 33.6 million people were blind and 206 million had moderate or severe vision impairment worldwide, most of which could have been avoided with adequate access to eye care services. Despite repeated efforts to assess eye care workforce distribution, data remain fragmented and incomplete. This study aimed to estimate the global number and distribution of ophthalmologists, optometrists, and allied ophthalmic personnel in 2023. Design Cross-sectional study using survey data supplemented by published data, primarily from academic sources, and key informants.Subjects, Participants, and/or Controls: Workforce data were available for ophthalmologists in 156 countries, optometrists in 166 countries, and allied ophthalmic personnel in 90 countries.Methods, Intervention, or Testing: Workforce data were collected by survey for each cadre. When survey data were incomplete, information was supplemented by national associations, societies, key informants, and ministries of health. Missing ophthalmologist data were estimated by applying the average income-level-specific growth rate calculated for 2015 to 2023 to the 2015 country estimates. Results The global ophthalmology workforce was estimated at 275,511 ophthalmologists, an increase of about forty-five thousand since 2015, with a density of 34 per million population. The optometry workforce was estimated at 306,711 optometrists globally, with a density of 39 per million. In countries where both professions were represented, those with more ophthalmologists generally also had more optometrists. The global allied ophthalmic personnel was estimated at 612,000 across 90 countries. Conclusions This study is the first attempt at providing a comprehensive global estimate of eye health professionals, revealing workforce gaps and the need to expand eye care capacity. The data highlight limitations in country-specific records of workforce numbers and the need for greater consistency in definitions of eye health professional roles and responsibilities. Further research should focus on standardizing data collection and estimating the minimum density and optimal mix of ophthalmologists, optometrists, and allied ophthalmic personnel needed for effective coverage of essential eye care services.
Non-orthogonal lenses, in which the principal meridians of the cylinder surfaces are not perpendicular to each other, can be used to improve vision in the condition of irregular astigmatism. A procedure is developed that allows raytracing and image-quality analysis with such lenses. A non-orthogonal surface was developed as a user-defined surface in the programme Ansys Zemax OpticStudio using a bi-cubic meridional mapping function. The function consists of two third-order polynomial sub-functions, each for mapping the actual ‘on surface’ meridian to an effective meridian that determines the meridional curvature for the two sectors of meridians bounded by the principal meridians. Equations were derived for partial derivatives across the surface, as Zemax requires these for raytracing through a user-defined surface. Examples are shown of tangential and pupil power maps for a thin orthogonal (conventional) +5.00 DS/+2.00 DC × 180 lens and for a non-orthogonal +5.00 DS/+2.00 DC (60) × 180 lens. The orthogonal lens has principal meridians 180° and 90° while the non-orthogonal lens has principal meridians 180° and 60°. For the orthogonal lens, both maps show regular changes in power with meridional angle, and the sagittal power map is rotated by 90° relative to the tangential power map. For the non-orthogonal lens, the sagittal power pattern shows sharp changes in power. The non-orthogonal surfaces were replicated using the ‘grid sag’ surface of Zemax, and the user-defined surface was verified. Surface fitting using Zernike polynomials returned only a reasonable approximation to a non-orthogonal surface. A type of non-orthogonal optical surface based on two third-order polynomials is presented. Aspects of its geometrical optics properties were investigated, including confirming the non-orthogonality of its axes. This type of surface may have utility in the correction of irregular astigmatism, such as occurs in keratoconus.
As myopia research expands in scope and complexity, the International Myopia Institute (IMI) continues to provide timely, evidence-based consensus guidance through its biennial white papers and digests. The IMI 2025 Digest delivers targeted updates in areas identified for revision since the previous digest: definitions and classification of myopia, clinical management guidelines, risk factors, accommodation and binocular vision, experimental models, and onset and progression in young adults. A major focus is the evolving concept of pre-myopia, including a refined understanding of hyperopic reserve as a predictive marker, population-specific thresholds, and the distinction between risk and predictive factors. Emerging evidence supports earlier identification and targeted interventions during the pre-myopic phase to delay onset. Clinical management updates highlight that delaying onset by even 1 year may have greater lifetime benefit than multiple years of progression control. Other updates address the limited causal inference of many current risk factor studies, new molecular insights from experimental models, and evidence that a subset of young adults, particularly with high myopia, continue to progress at meaningful rates. Collectively, the IMI 2025 Digest underscores the importance of proactive, individualized myopia care, equipping clinicians with current, evidence-based guidance while supporting continued research and innovation.
Blindness is a health and social concern of significant public health dimensions that has not received the adequate attention it warrants on the global health and development agenda. Over the past three decades, the global prevalence of blindness and vision impairment has decreased, but the aging population is increasingly rapidly, causing an increase in the number of people with age-related vision loss, with low- and middle-income regions carrying the brunt of the global burden. The trends in global blindness have transitioned from infection- and nutrition-related causes of blinding eye diseases to those of a chronic nature that generally stem from noncommunicable disorders. This is in keeping with the demographic transition that is occurring at an enhanced pace in the low- and middle-income regions of the world, consequent to their inevitable population momentum. These transitions have far-reaching con.sequences for population eye health, in terms of underdevelopment, social costs, poverty alleviation, and the quality of life of affected individuals and communities, in particular. Global political commitment to the prevention of blindness has been recently reaffirmed by the adoption of the World Health Organization of Resolution WHA73.4 (2020), Integrated people-centered eye care, including preventable vision impairment and blindness, which implements the recommendations of the World Report on Vision to integrate eye care into universal health coverage and contributes to United Nations Sustainable Development Goal 3 to universally ensure healthy lives and promote well-being. Sustainable, equitable, and comprehensive eye care systems integrated into national health systems and based on the principles of primary health care are urgently needed to meet the global population's increasing eye health needs.
