A pilot study of axial length changes associated with myopia control spectacles in subjects reading under mesopic conditions.

PURPOSE: To investigate whether axial length changes in subjects wearing myopia control spectacles under mesopic conditions. METHODS: Young users of monofocal spectacles with myopic spherical equivalent ranging from -1.00 D to -5.00 D were enrolled prospectively. Subjects were tested while using a pair of special defocus spectacles with a central zone including the distance myopic correction and a peripheral zone with an addition of +3.50 D. Subjects first read an online book with black letters on white background on a desktop computer with their monofocal spectacles for 20 minutes and then read with special defocus spectacles for another 20 minutes. Reading took place in a darkened room under 20 lux illumination. Before and after these periods, axial length of the right eye was measured ten times using the Lenstar, and average measurements were recorded. RESULTS: The 11 subjects in this pilot study had a mean age of 20.9 ± 7.7 years, and 1 was female. Their mean spherical equivalent of the right eyes was -3.20 ± 2.29 D. As expected, axial length increased by 8.2 ± 9.4 µm (P < 0.01) after 20 minutes of reading with monofocal spectacles in low light. When reading with defocus spectacles under the same conditions, the axial length saw an additional, nonsignificant change of 2.2 ± 12.2 µm (P = 0.56). CONCLUSIONS: When reading in mesopic conditions, the axial length in study subjects did not return to baseline values with myopia control spectacles.

Retinal shadows produced by myopia control spectacles.

PURPOSE: To analyse ocular coherence tomography (OCT) images of the retinal shadows caused by defocus and diffusion optics spectacles. METHODS: One eye was fitted successively with the Hoya Defocus Incorporated Multiple Segments (DIMS) spectacle lens, two variations of the +3.50 D peripheral add spectacle (DEFOCUS) and the low-contrast dot lens (Diffusion Optics Multiple Segments, DOMS); each at a vertex distance of 12 mm. Simultaneously, a retinal image of the macular region with central fixation was obtained using infrared OCT. The corneal power and intraocular distances were determined using an optical biometer. RESULTS: The retinal images for the DIMS and DOMS lenses showed patterns of obvious retinal shadows in the periphery, while the central 10-11° remained clear. The DEFOCUS lens produced a darkened peripheral area. Dividing the size of the retinal pattern, measured with the calliper of the OCT software, by the actual size on the spectacle lens gave a magnification of -0.57 times. This is consistent with the incoming OCT beam being imaged to a position approximately 31 mm beyond the front of the eye. [Correction added on 26 October 2023 after first online publication: The preceding paragraph was corrected.] CONCLUSION: With device-specific correction, retinal OCT images can help visualise the regions affected by the defocus or lowered contrast induced by myopia control spectacles. This is of potential value for improving myopia therapies.

Role of tutorial classes and full day schooling on self-reported age of myopia onset: findings in a sample of Argentinian adults.

PURPOSE: To investigate the effect of tutorial classes and schooling schedule in childhood on age of myopia onset. METHODS: Refractive data for subjects ≥18 years of age were collected from 8 dispensing opticians or refractive ophthalmologists' offices in Argentina. Age of myopia onset, spherical equivalent (SE), and risk factors were determined using questionnaires. Multiple linear regression models were applied to assess possible factors associated with age of myopia onset or final adult SE. RESULTS: A total of 274 adults (61.3% females) with myopia between -0.50 and -6.00 D were included. Mean age was 36.9 ± 14.5 years. The mean adult SE was -2.95 ± 1.45 D, and the mean age of myopia onset was 14.2 ± 5.4 years. Subjects that attended after-school tutorial classes (ß = -2.23; P = 0.005) or a full day schedule in primary school (ß = -1.07; P = 0.035) or that spent more time on near work (ß = -0.70; P = 0.010) in childhood, had younger age of myopia onset. CONCLUSIONS: In our study cohort, adults that had attended tutorial classes and/or full-day schooling during childhood had younger age of myopia onset.