Convergence Study of High Refractive Index Polarized Glasses Lens with Photochromic and UV Blocking Function

Those who use convex or concave lenses should use sunglasses made from regular spectacle lenses. In this case, it uses a surface coating to block UV rays, so it is relatively vulnerable to UV protection. To this end, we developed a spectacle lens that can completely block ultraviolet light and suppress blue light by using a monomer that completely blocks the area below 410 nm and has a sunglasses function through photochromic function. A spectacle lens with photochromic, polarization and UV blocking functions was developed using a monomer with a high refractive index of 1.67. In the photochromic property, a recovery time of 2 minutes for light reaction and 5 minutes for dark reaction was obtained. Five layers of anti-reflection coating were applied to the surface of the lens to reduce the transmittance in the visible light region to 0.1 or less. ITO was applied to give an electromagnetic wave shielding function, and the thickness and conductivity of ITO were proportional to the result. The blue light emitted from the LED is reduced by more than 30% to reduce eye fatigue. UV rays were completely blocked below 410 nm. Keywords—Ultra violet, Blue light, Sunglass, Photochromic, Eyeglass lenses

The Refractive Error and Vision Impairment Estimation With Spectacle data (REVIEWS) study

Objective: To investigate whether spectacle lens sales data can be used to estimate the population distribution of refractive error amongst ametropes and hence estimate the current and future risk of vision impairment. Design: Cross Sectional Study Subjects: A total 141,547,436 spectacle lens sales records from an international European lens manufacturer between the years 1998 and 2016. Methods: Anonymized patient spectacle lens sales data including refractive error information was provided by a major European spectacle lens manufacturer. Data from the Gutenberg Health Survey was digitized to allow comparison of a representative, population-based sample to the spectacle lens sales data. A bootstrap analysis was completed to assess the comparability of both datasets. The expected level of vision impairment due to myopia at age 75 was calculated for both datasets using a previously published risk estimation equation combined with a saturation function. Main Outcome Measures: Comparability of spectacle lens sales data on refractive error to typical population surveys of refractive error and its potential utility to predict vision impairment due to refractive error. Results: Equivalent estimates of the population distribution of spherical equivalent refraction can be provided from spectacle lens data within limits. For myopia, the population distribution was equivalent to the Gutenberg Health Survey (≤ 5% deviation) for levels ≤-2.0 dioptres, while for hyperopia the distribution was equivalent (≤ 5% deviation) for levels ≥ +3.0 diopters. The estimated rates of vision impairment due to myopia were not statistically significantly different (χ2 = 182, DoF = 169, p = 0.234) between the spectacle lens data and Gutenberg Health Survey data. Conclusions: The distribution of refractive error and hence the risk of vision impairment due to refractive error within a population can be determined using spectacle lens sales data. Pooling this type of data from multiple industry sources could provide a cost effective, timely and globally representative mechanism for monitoring the evolving epidemiology of refractive error and associated vision impairment.

Comparison of contrast sensitivity in myopic patients using spectacle and contact lens correction

Aim: To compare the contrast sensitivity in different categories of myopia using two different optical correction spectacles and contact lens correction. Methods: This cross-sectional study in design was conducted from August 2018 to May 2019 at the Ophthalmology Department of Madinah Teaching Hospital Faisalabad.45 subjects corrected with spectacles lenses and contact lenses all had corrected visual acuity of 6/9 or better were studied.The extent of myopia determined the three groups. All individuals were subjected to spectacles and Contact lens correction using slitlamp for anterior eye examination and for the fundus examination. The assessment of visual acuity was carried out by the Snellen vision Chart at 6m distance and contrastssensitivity was tested by Pelli- Robson chart. Results: Results showed a significant relationship between contrast sensitivity and type of optical correction. There were significant results of the independent t-test for spectacle and contact lenses 0.00 (p<0.005). However, the mean contrast sensitivity was better for all the three groupswith contact lens correction as compared to spectacle lens correction.Contact lenses provide better contrast sensitivity than spectacle lenses. Conclusion: Comparison between contact lens and spectacle correction was done and better quality contact lenses reduce optical defocus and give better results of contrast sensitivity. Results also concluded that loss of contrast sensitivity will be interpreted as early loss of retinal functions in severe myopes. Keywords: Myopia, Contrast sensitivity, Spectacle lens, Contact lens

Application of big-data for epidemiological studies of refractive error

Purpose To examine whether data sourced from electronic medical records (EMR) and a large industrial spectacle lens manufacturing database can estimate refractive error distribution within large populations as an alternative to typical population surveys of refractive error. Subjects A total of 555,528 patient visits from 28 Irish primary care optometry practices between the years 1980 and 2019 and 141,547,436 spectacle lens sales records from an international European lens manufacturer between the years 1998 and 2016. Methods Anonymized EMR data included demographic, refractive and visual acuity values. Anonymized spectacle lens data included refractive data. Spectacle lens data was separated into lenses containing an addition (ADD) and those without an addition (SV). The proportions of refractive errors from the EMR data and ADD lenses were compared to published results from the European Eye Epidemiology (E3) Consortium and the Gutenberg Health Study (GHS). Results Age and gender matched proportions of refractive error were comparable in the E3 data and the EMR data, with no significant difference in the overall refractive error distribution (χ2 = 527, p = 0.29, DoF = 510). EMR data provided a closer match to the E3 refractive error distribution by age than the ADD lens data. The ADD lens data, however, provided a closer approximation to the E3 data for total myopia prevalence than the GHS data, up to age 64. Conclusions The prevalence of refractive error within a population can be estimated using EMR data in the absence of population surveys. Industry derived sales data can also provide insights on the epidemiology of refractive errors in a population over certain age ranges. EMR and industrial data may therefore provide a fast and cost-effective surrogate measure of refractive error distribution that can be used for future health service planning purposes.

A strategically oriented conception of optical prevention of myopia onset and progression

The article presents a theoretical and clinical justification for optical techniques used for the prevention of myopia. Accommodation, wavefront aberrations, peripheral refraction, and retinal image quality are considered as interrelated factors affecting postnatal refractogenesis. A detailed analysis of myopia correction methods, conditions preceding its development and their impact on the dynamics of refraction and eye growth is given. A strategy of optical correction of myopia was proposed, which includes: 1) constant wearing of defocusing binocular positive spectacle lens or Perifocal-P spectacle lens (in case of exophoria) for children at risk aged 4–7 years; 2) constant alternating weak myopic defocusing in case of myopia from 0.5 to 2.75 D, ortho- or esophoria, positive relative accommodation (PRA), peripheral myopia or emmetropia; progressive addition spectacle lens in case of PRA less than 1.0 D; Perifocal-Msa spectacle lens in the case of a combination of reduced PRA and exophoria; 3) Perifocal-M spectacle lens in case of myopia of any degree with already existing hyperopic peripheral defocus; progressive addition spectacle lens in case of PRA less than 1.0 D in combination with esophoria or Perifocal-Msa spectacle lens in combination with exophoria; 4) contact correction with bifocal soft contact lenses or orthokeratological contact lenses (Ortho-K) in case of refusal from spectacle correction. Ortho-K is preferable with moderate and high myopia; 5) bioptic correction: a combination of monofocal soft contact lenses and Perifocal-M spectacle lens to correct peripheral defocus and residual astigmatism is preferable for myopia over 8.0 D and myopia with astigmatism.