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 The impact of wearing single vision soft contact lenses on the peripheral refractive error

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2803
Author(s):  
Kareem Allinjawi ◽  
Sharanjeet-Kaur Sharanjeet-Kaur ◽  
Saadah Mohamed Akhir ◽  
Haliza Abdul Mutalib
Keyword(s):  
Visual Field ◽  
Open Field ◽  
Refractive Error ◽  
Contact Lens ◽  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Single Vision ◽  
The Right ◽  
The Impact

Aim: The purpose of this study was to determine the changes in the relative peripheral refractive error produced by soft single vision contact lenses in myopic schoolchildren. Methods: 27 myopic schoolchildren aged between 13 to 15 years were included in this study. The measurements of central and peripheral refraction were made only on the right eye using a Grand-Seiko WR-5100K open-field autorefractometer without contact lens (WL), and with wearing single vision contact lens (SVCL). Refractive power was measured at center and horizontal eccentricity between 35° temporal to 35° nasal visual field (in 5° steps). Results: SVCL showed an increase in peripheral hyperopic defocus at the nasal and temporal visual field compare with baseline, but this change was not statistically significant (p=0.129). Conclusion: Wearing single vision soft contact lenses increases the relative peripheral hyperopic defocus in myopic schoolchildren.

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 Infectious Keratitis Associated with Contact Lenses

2021 ◽  
Vol 20 (4) ◽  
pp. 140-143
Author(s):  
Kyong Jin Cho
Keyword(s):  
Patient Education ◽  
Contact Lens ◽  
Contact Lenses ◽  
Infectious Keratitis ◽  
Corneal Surface ◽  
Corneal Epithelial Cells ◽  
Myopia Progression ◽  
Corneal Epithelial ◽  
Corneal Infection ◽  
Tear Flow

The use of contact lenses for correcting refraction, suppressing myopia progression, and cosmetic purposes is increasing steadily. Contact lenses have various effects on the corneal surface and corneal infection can occur following obstruction of tear flow, micro-damage to corneal epithelial cells, corneal hypoxia, changes in corneal immunity, and exposure to contaminants. When a patient who used to wear contact lenses presents with keratitis, it is important to distinguish whether it is an infection; if it is an infection, it is important to find the causative strain and promptly treat it appropriately. Since improper lens care is related to infection, appropriate patient education is necessary, and the risk of contact lens infection should be reduced through regular ophthalmic examinations.

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 Ocular and corneal aberrations changes in controlled randomized clinical trial MiSight® Assessment Study Spain (MASS)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Daniela Lopes-Ferreira ◽  
Alicia Ruiz-Pomeda ◽  
Belén Peréz-Sanchéz ◽  
António Queirós ◽  
César Villa-Collar
Keyword(s):  
Clinical Trial ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
High Order ◽  
Control Group ◽  
Myopia Progression ◽  
Corneal Aberrations ◽  
Single Vision ◽  
Control Versus ◽  
Low Order

Abstract Background To compare ocular and corneal inherent aberrations in the naked eyes of randomly selected children fitted with MiSight contact lenses (CL) for myopia control, versus children corrected with single-vision spectacles (control), over a 24-months period. Methods Children aged 8 to 12 years, with myopia (-0.75 to -4.00 D sphere) and astigmatism (< -1.00 D cylinder) were randomly assigned to the lens study group (MiSight) or the control group (single-vision spectacles). The root mean square aberration (RMS) was determined as corneal (RMS_C), corneal high order RMS (HO_RMS_C), corneal low order RMS (LO_RMS_C), ocular (total) RMS (RMS_T), ocular high order RMS (HO_RMS_T), ocular low order RMS (LO_RMS_T), corneal spherical aberration (SA_C) and ocular SA (SA_T) were calculated by aberrometry measures at the baseline, on 12-months and 24-months visits. A 5 mm diameter was defined for the analysis in all visits for all subjects. Only the dominant eye was analyzed. Results Seventy-four subjects completed the clinical trial: 41 subjects from the MiSight group (age: 11.01 ± 1.23 years) and 33 from the single-vision group (age: 10.12 ± 1.38 years). RMS_T significantly changed (0.57 ± 0.20 µm, p = 0.029) after 24-months in the control group. In the MiSight group no significant changes were registered (p > 0.05). The SA_C and SA_T did not reveal significant changes between visits or between groups (p > 0.05). Conclusions Along 2 years, MiSight CL did not induce significant changes in RMS of anterior cornea or total ocular RMS. Contrary, in control group the RMS_T significantly changed as response of greater eye growth and myopia progression. The results obtained in present study allow to predict corneal or total aberration changes, in children, in response of wearing of MiSight lens along the time. Trial registration : ClinicalTrials.gov Identifier: NCT01917110.

scholarly journals The short-term effects of PMMA contact lens wear on keratometric behaviour: results for a single keratoconic cornea*

2010 ◽  
Vol 69 (2) ◽  
Author(s):  
E. Chetty ◽  
W. D. H. Gillan
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Corneal Curvature ◽  
Short Term ◽  
Multivariate Statistical ◽  
Contact Lens Wear ◽  
Rigid Contact ◽  
Dioptric Power ◽  
Control Study ◽  
Lens Wear

Keratometric behaviour is a multifaceted issue that many researchers have investigated for years. Many internal and external influences can have an effect on the cornea’s keratometric behaviour. This investigation forms a small part of a larger study that aims at determining the effects that rigid contact lenses might have on keratometric behaviour. This pilot study examined the keratometric behaviour of a single, mildly keratoconic cornea that was fitted with a polymethyl methacrylate (PMMA) contact lens. Sixty successive auto-keratometric measurements were taken immediately before and immediately after three hours of contact lens wear. The data obtained was transformed to dioptric power matrices and were analysed using multivariate statistical methods. This study showed that, at least in one keratoconic cornea, there appeared to be a statistically significant change in corneal curvature under the influence of a PMMA contact lens. The contact lens had also appeared to decrease variation in corneal curvature. There was no control study done on this eye therefore the effects of diurnal variation, if any, could not be established. (S Afr Optom 2010 69(2) 69-76)

scholarly journals Ocular and Corneal Aberrations changes in controlled randomized clinical trial MiSight® Assessment Study Spain (MASS)

2020 ◽  
Author(s):  
DANIELA LOPES-FERREIRA ◽  
Alicia Ruiz-Pomeda ◽  
Belén Peréz-Sanchéz ◽  
António Queirós ◽  
César Villa-Collar
Keyword(s):  
Clinical Trial ◽  
Axial Length ◽  
Contact Lenses ◽  
Spherical Aberration ◽  
High Order ◽  
Control Group ◽  
Myopia Progression ◽  
Corneal Aberrations ◽  
Single Vision ◽  
Low Order

Abstract BackgroundTo compare ocular and corneal inherent aberrations in the naked eyes of randomly selected children fitted with MiSight contact lenses (CL) for myopia control, versus children corrected with single-vision spectacles (control), over a 24-months period.MethodsChildren aged 8 to 12 years, with myopia (-0.75 to -4.00 D sphere) and astigmatism (< -1.00 D cylinder), were assigned to the lens study group (MiSight) or the control group (single-vision spectacles). Axial length (AL) was measured by biometry, corneal RMS (RMS_C), corneal high order RMS (HO_RMS_C), corneal low order RMS (LO_RMS_C), ocular total RMS (RMS_T), ocular total high order RMS (HO_RMS_T), ocular total low order RMS (LO_RMS_T), corneal spherical aberration (SA_C) and ocular total SA (SA_T) were calculated by aberrometric measures at the baseline, and on 12- and 24-months visits. A 5 mm diameter was defined for the analysis in all visits for all subjects. Only the dominant eye was analyzed.ResultsSeventy-four subjects completed the clinical trial: 41 subjects from the MiSight group (age: 11.01 ± 1.23 years) and 33 from the single-vision group (age: 10.12 ± 1.38 years). In the control group, axial length changed significantly (0.444 ± 0.049 mm, p < 0.001) after 2 years. Also RMS_T (0.565 ± 0.199 µm, p = 0.029) and LO_RMS_T (0.461 ± 0.175 µm, p = 0.047) registered significant changes after 24-months in the control group. In the MiSight group, only axial length changed significantly (0.284 ± 0.025 mm, p < 0.001) after 2 years. The SA_C and SA_T did not reveal significant changes between visits or between groups.ConclusionsThe wear of MiSight CL did not induce significant changes in aberrations in anterior cornea and contrary of control group the total ocular RMS and low order RMS did not significantly caused by significantly lower eye growth and myopia progression,Trial registration: ClinicalTrials.gov Identifier: NCT01917110.

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.

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