scholarly journals Modern optical methods of peripheral defocus correction

2019 ◽  
Vol 12 (4) ◽  
pp. 92-98 ◽  
Author(s):  
S. V. Milash ◽  
M. V. Epishina ◽  
R. R. Toloraya
Keyword(s):  
Experimental Animal ◽  
Animal Studies ◽  
Optical Methods ◽  
Myopia Progression ◽  
Eye Growth ◽  
Retinal Periphery ◽  
Speed Up ◽  
Spectacle Correction ◽  
Myopia Control

Experimental animal studies proved that by manipulating with the defocus one can slow down or speed up the eye growth. The leading mechanism among modern optical strategies of myopia progression treatment is to induce myopic defocus to retinal periphery or decrease the hyperopic defocus. This review sums up the data on peripheral refraction in orthokeratological, multifocal contact, and multifocal spectacle correction. The effectiveness of these methods in myopia control in children and teenagers is shown.

scholarly journals Multi-Factoral Mechanisms of Therapeutic Effect of Perifocal Spectacles (Perifocal-M) on Progressive Myopia in Children

2019 ◽  
Vol 15 (4) ◽  
pp. 433-438 ◽  
Author(s):  
R. A. Ibatulin ◽  
O. V. Proskurina ◽  
E. P. Tarutta
Keyword(s):  
Regulatory Control ◽  
Optical Methods ◽  
Myopia Progression ◽  
Detailed Review ◽  
Eye Growth ◽  
Progressive Myopia ◽  
Near Work ◽  
First Time ◽  
Complex Influence ◽  
Myopia Control

There is detailed review of multi-factoral mechanisms of spectacles with peripheral defocus influence in children with progressive myopia in this article. At present local retinal mechanisms of neuro-regulatory control of eye growth are most effective in prevention of myopia development and progression. Optical correction of relative peripheral hyperopia with following peripheral myopic defocus affects the biochemical cascade from retina to choroid and sclera, which constrains an eye growth. Optical methods of myopia control, including spectacles, widely used in native and foreign ophthalmology practice. Since 2011, in Russia Perifocal-M spectacles are using, said spectacles provides bigger functionality of influence on myopic eye comparing to foreign analogues. Construction features of said spectacle lens have a complex influence on different optic-physiological eye structures and each of said structures affects refractogenesis. Perifocal spectacles takes into account specific for myopic eye features of central and peripheral refraction along horizontal and vertical meridians. They have stronger refraction in horizontal, which allows to eliminate specific optical disbalance in myopic eye and to create optical balance in the eye. Perifocal-M lens construction with asymmetric horizontal progression allows to correct relative peripheral hyperopia, to create myopic defocus in horizontal and to affect relations between refraction of nasal and temporal halves of retina. The latter is due to the fact that optical influence starts earlier and has bigger effect on nasal half of retina relative to temporal. Perifocal spectacles are inducing positive spherical aberrations in the eye, increasing accommodation functions, supporting high binocular visual acuity, improving binocular interaction during near work, fighting against heteroforias. Thus, optical features of Perifocal-M spectacles for the first time creates conditions for versatile functional influence on main myopogenic factors simultaneously, it effectively stops myopia progression.

scholarly journals Effect of Peripheral Defocus on Axial Eye Growth and Modulation of Refractive Error in Hyperopes: Protocol for a Nonrandomized Clinical Trial (Preprint)

2018 ◽  
Author(s):  
Ian G Beasley ◽  
Leon N Davies ◽  
Nicola S Logan
Keyword(s):  
Refractive Error ◽  
Contact Lens ◽  
Animal Studies ◽  
Contact Lenses ◽  
Myopia Progression ◽  
Fellow Eye ◽  
Eye Growth ◽  
Single Vision ◽  
Natural Progression ◽  
Control Study

BACKGROUND Hyperopia occurs due to insufficient ocular growth and a failure to emmetropize in childhood. In anisohyperopia, it is unclear why one eye may remain hyperopic while the fellow eye grows toward an emmetropic state. Animal studies have shown that manipulating peripheral defocus through optical means while simultaneously providing correct axial focus can either discourage or encourage axial eye growth to effectively treat myopia or hyperopia, respectively. Myopia progression and axial eye growth can be significantly reduced in children and adolescents through the use of multifocal contact lenses. These contact lenses correct distance central myopia while simultaneously imposing relative peripheral myopic defocus. The effect of correcting distance central hyperopia while simultaneously imposing relative peripheral hyperopic defocus is yet to be elucidated in humans. OBJECTIVE The objective of our study is to understand the natural progression of axial eye growth and refractive error in hyperopes and anisohyperopes and to establish whether axial eye growth and refractive error can be modified using multifocal contact lenses in hyperopes and anisohyperopes. METHODS There are 3 elements to the program of research. First, the natural progression of axial eye growth and refractive error will be measured in spectacle-wearing hyperopic and anisohyperopic subjects aged between 5 and <20 years. In other words, the natural growth of the eye will be followed without any intervention. Second, as a paired-eye control study, anisohyperopes aged between 8 and <16 years will be fitted with a center-near multifocal design contact lens in their more hyperopic eye and a single-vision contact lens in the fellow eye if required. The progression of axial eye growth and refractive error will be measured and compared. Third, subjects aged between 8 and <16 years with similar levels of hyperopia in each eye will be fitted with center-near multifocal design contact lenses in each eye; the progression of axial eye growth and refractive error in these subjects will be measured and compared with those of subjects in the natural progression study. RESULTS Recruitment commenced on 6 June 2016 and was completed on 8 April 2017. We estimate the data collection to be completed by April 2020. CONCLUSIONS This trial will establish whether axial eye growth can be accelerated in children with hyperopia by imposing relative peripheral hyperopic defocus using center-near multifocal contact lenses. CLINICALTRIAL ClinicalTrials.gov NCT02686879; https://clinicaltrials.gov/ct2/show/NCT02686879 (Archived by Webcite at http://www.webcitation.org/71o5p3fD2) REGISTERED REPORT IDENTIFIER RR1-10.2196/9320

scholarly journals Orthokeratology lenses and myopia control

The Eye ◽  
2019 ◽  
Vol 126 (2019-2) ◽  
pp. 13-20
Author(s):  
Pyotr Nagorsky ◽  
Nikolai Kikhtenko ◽  
Vera Milyukhina
Keyword(s):  
Axial Length ◽  
Growth Dynamics ◽  
Control Group ◽  
Myopia Progression ◽  
Eye Growth ◽  
Vision Correction ◽  
Uncorrected Visual Acuity ◽  
Progressive Myopia ◽  
Observation Period ◽  
Myopia Control

Purpose: To estimate the stabilizing effect of orthokeratology lenses (ortho-K, OK-lenses) on myopia progression by evaluating axial eye growth dynamics and clinical refraction. Material and methods. Ortho-K group consisted of 68 children (135 eyes) aged 7–17 years (mean age 12.2) with progressive myopia (initially -0.75–6.75 D). Observation period varied from 7 to 30 months (mean period 11.68±4.39). All patients used OK-lenses for overnight wear. The control group consisted of 90 patients (180 eyes) with myopia who were prescribed single vision spectacles for vision correction. Comparative analysis was performed for clinical refraction parameters as well as for axial length (AL). The data was obtained with the use of IOL-Master optical biometer (“Carl Zeiss”). Results. The parameters were stable in patients of ortho-K group: axial length, subjective and objective clinical refraction, the required power of corrective lenses. However, the parameters changed significantly in the control group during the observation period: uncorrected visual acuity (UCVA) decreased, the required power of corrective lenses increased, the indices of objective clinical refraction strengthened, annual gradient of progression (AGP) amounted to 0.26±0.19 and 0.16±0,39 mm in patients with low and moderate myopia, respectively. Conclusion. The use of OK-lenses ensures a significant deceleration of myopia progression in children. The results obtained suggest a wider use of ortho-K among pediatric ophthalmologists in their clinical practice as it is an effective preventive and therapeutic method for patients with progressive myopia.

scholarly journals Myopia and defocus: the current understanding

2011 ◽  
Vol 4 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Mhairi Day ◽  
Lorraine A Duffy
Keyword(s):  
Animal Studies ◽  
Large Body ◽  
Current Understanding ◽  
Group Differences ◽  
Unified Theory ◽  
Insufficient Evidence ◽  
Potential Influence ◽  
Myopia Progression ◽  
Eye Growth

The current theories relating to the development and progression of myopia are related to exposure of the eye to hyperopic defocus. This paper discusses these theories and the large body of recent research investigating the evidence behind them. As both human and animal studies demonstrate, when considering the potential influence of defocus on eye growth, the duration of exposure as well as the type and magnitude of the blur are important. In addition, we must understand the defocus threshold over which an eye growth signal can be made. Investigations with respect to central defocus alone have been unable to find a unified theory due to (1) insufficient evidence showing refractive group differences in the amount of central defocus actually present and (2) unsuccessful attempts to wholely reduce myopia progression using corrective lenses. Recent research measuring peripheral blur is summarised in this paper and modelled together with previous measurements of peripheral defocus thresholds, providing an up-to-date perspective on myopia.

scholarly journals To Correct or Not Correct? Actual Evidence, Controversy and the Questions That Remain Open

2020 ◽  
Vol 9 (6) ◽  
pp. 1975
Author(s):  
Miguel García García ◽  
Katharina Breher ◽  
Arne Ohlendorf ◽  
Siegfried Wahl
Keyword(s):  
Basic Research ◽  
Control Group ◽  
Myopia Progression ◽  
Ethical Implications ◽  
Eye Growth ◽  
Single Vision ◽  
Full Correction ◽  
New Guidelines ◽  
Lens Wear ◽  
Myopia Control

Clinical studies and basic research have attempted to establish a relationship between myopia progression and single vision spectacle wear, albeit with unclear results. Single vision spectacle lenses are continuously used as the control group in myopia control trials. Hence, it is a matter of high relevance to investigate further whether they yield any shift on the refractive state, which could have been masked by being used as a control. In this review, eye development in relation to eyes fully corrected versus those under-corrected is discussed, and new guidelines are provided for the analysis of structural eye changes due to optical treatments. These guidelines are tested and optimised, while ethical implications are revisited. This newly described methodology can be translated to larger clinical trials, finally exerting the real effect of full correction via single vision spectacle lens wear on eye growth and myopia progression.

scholarly journals Additive effect of atropine eye drops and short-term retinal defocus on choroidal thickness in children with myopia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Samuel T.-H. Chiang ◽  
Philip R. K. Turnbull ◽  
John R. Phillips
Keyword(s):  
Eye Drops ◽  
Additive Effects ◽  
Short Term ◽  
Myopia Progression ◽  
Eye Growth ◽  
Slow Progression ◽  
Before And After ◽  
Atropine Treatment ◽  
Optical Defocus ◽  
Myopia Control

Abstract Atropine eye drops and myopic retinal defocus each slow progression of myopia (short-sight). They also cause thickening of the choroid, and it has been suggested that the thickening is a precursor for reduced eye growth and slowed myopia progression. We investigated whether choroidal thickening due to optical defocus would add to thickening due to atropine when both were applied simultaneously. Addition would suggest that combining the two clinical treatments may improve efficacy of myopia control. We studied 20 children receiving 0.3% atropine daily for myopia control, over a period of 6 months. We imposed short periods of retinal defocus (1 h of myopic or hyperopic defocus (± 2.00D)) both before, and after 1 week and 3 and 6 months of atropine treatment. Prior to atropine, myopic or hyperopic defocus caused significantly thicker or thinner choroids respectively (± 12 µm, p < 0.001). After one week of atropine alone, thickness had increased (+ 21 µm; SD 17 µm; p < 0.001), and it increased further (by + 13 µm; SD 6 µm; p < 0.001) when exposed to myopic defocus. Atropine abolished choroidal thinning in response to hyperopic defocus. These effects remained the same after 3 and 6 months of atropine treatment. Our results show that additive effects of atropine and optical defocus are present at the level of the choroid, and suggest that combining optical and pharmaceutical treatments is likely to enhance efficacy of clinical myopia control.

scholarly journals Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

2021 ◽  
pp. 112067212199896
Author(s):  
János Németh ◽  
Beáta Tapasztó ◽  
Wagih A Aclimandos ◽  
Philippe Kestelyn ◽  
Jost B Jonas ◽  
...  
Keyword(s):  
European Society ◽  
High Myopia ◽  
Treatment Options ◽  
Vision Impairment ◽  
Pathological Myopia ◽  
Myopia Progression ◽  
Preventive Actions ◽  
Prevalence Estimates ◽  
Number Of Individuals ◽  
Myopia Control

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

scholarly journals Myopia control effect of defocus incorporated multiple segments (DIMS) spectacle lens in Chinese children: results of a 3-year follow-up study

2021 ◽  
pp. bjophthalmol-2020-317664
Author(s):  
Carly SY Lam ◽  
Wing Chun Tang ◽  
Paul H Lee ◽  
Han Yu Zhang ◽  
Hua Qi ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Mean Difference ◽  
Historical Control ◽  
Control Group ◽  
Control Effect ◽  
Myopia Progression ◽  
The Third ◽  
Spherical Equivalent Refraction ◽  
Mean Differences ◽  
Myopia Control

AimsTo determine myopia progression in children who continued to wear the defocus incorporated multiple segments (DIMS) lenses or switched from single vision (SV) to DIMS lenses for a 1-year period following a 2-year myopia control trial.Methods128 children participated in this study. The children who had worn DIMS lenses continued to wear DIMS lenses (DIMS group), and children who had worn SV lenses switched to wear DIMS lenses (Control-to-DIMS group). Cycloplegic spherical equivalent refraction (SER) and axial length (AL) were measured at 6-month interval. Historical controls were age matched to the DIMS group at 24 months and used for comparing the third-year changes.ResultsOver 3 years, SER and AL changes in the DIMS group (n=65) were −0.52±0.69D and 0.31±0.26 mm; these changes were not statistically significant over time (repeated measures analysis of variance, p>0.05).SER (−0.04±0. 38D) and AL (0.08±0.12 mm) changes in the Control-to-DIMS group (n=55) in the third year were less compared with the first (mean difference=0.45 ± 0.30D, 0.21±0.11 mm, p<0.001) and second (0.34±0.30D, 0.12±0.10 mm, p<0.001) years.Changes in SER and AL in both groups over that period were significantly less than in the historical control group (DIMS vs historical control: mean difference=−0.18±0.42D, p=0.012; 0.08±0.15 mm, p=0.001; Control-to-DIMS versus historical control: adjusted mean differences=−0.30±0.42D, p<0.001; 0.12±0.16 mm, p<0.001).ConclusionsMyopia control effect was sustained in the third year in children who had used the DIMS spectacles in the previous 2 years and was also shown in the children switching from SV to DIMS lenses.

scholarly journals Myopia Control with Combination Low-Dose Atropine and Peripheral Defocus Soft Contact Lenses: A Case Series

2021 ◽  
pp. 548-554
Author(s):  
Nir Erdinest ◽  
Naomi London ◽  
Nadav Levinger ◽  
Yair Morad
Keyword(s):  
Low Dose ◽  
Contact Lenses ◽  
Case Series ◽  
Concentric Circle ◽  
Retrospective Case ◽  
Soft Contact ◽  
Myopia Progression ◽  
Soft Contact Lenses ◽  
Center Distance ◽  
Myopia Control

The goal of this retrospective case series is to demonstrate the effectivity of combination low-dose atropine therapy with peripheral defocus, double concentric circle design with a center distance soft contact lenses at controlling myopia progression over 1 year of treatment. Included in this series are 3 female children aged 8–10 years with progressing myopia averaging −4.37 ± 0.88 D at the beginning of treatment. Their average annual myopic progression during the 3 years prior to therapy was 1.12 ± 0.75 D. They had not attempted any myopia control treatments prior to this therapy. The children were treated with a combination of 0.01% atropine therapy with spherical peripheral defocus daily replacement soft lenses MiSight<sup>®</sup> 1 day (Cooper Vision, Phoenix, AZ, USA). They underwent cycloplegic refraction, and a slit-lamp evaluation every 6 months which confirmed no adverse reactions or staining was present. Each of the 3 children exhibited an average of 0.25 ± 0.25 D of myopia progression at the end of 1 year of treatment. To the best of the authors’ knowledge, this is the first published study exhibiting that combining low-dose atropine and peripheral defocus soft contact lenses is effective at controlling children’s moderate to severe myopia progression during 1 year of therapy.

A systematic review of experimental animal studies on microbial bioaerosols: Dose-response data for the derivation of exposure limits

2019 ◽  
Vol 222 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Mihai Zamfir ◽  
Doris G. Gerstner ◽  
Sandra M. Walser ◽  
Jürgen Bünger ◽  
Thomas Eikmann ◽  
...  
Keyword(s):  
Systematic Review ◽  
Experimental Animal ◽  
Dose Response ◽  
Animal Studies ◽  
Exposure Limits ◽  
Response Data
Sign in / Sign up

Export Citation Format

Share Document