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result(s) for
"Axial Length, Eye - physiology"
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Defocus Incorporated Soft Contact (DISC) lens slows myopia progression in Hong Kong Chinese schoolchildren: a 2-year randomised clinical trial
by
To, Chi Ho
,
Tang, Wing Chun
,
Tse, Dennis Yan-Yin
in
Adolescent
,
Axial Length, Eye - physiology
,
Child
2014
Aims To determine if ‘Defocus Incorporated Soft Contact’ (DISC) lens wear slows childhood myopia progression. Methods A 2-year double-blind randomised controlled trial was carried out in 221 children aged 8–13 years, with myopia between −1.00 and −5.00 Dioptres (D) and astigmatism ≤1.00 D. Subjects were randomly assigned to the DISC (n=111) or single vision (SV; n=110) contact lens group. DISC lenses incorporated concentric rings, which provided an addition of +2.50 D, alternating with the normal distance correction. Refractive error (cycloplegic autorefraction) and axial length were measured at 6-month intervals. Differences between groups were analysed using unpaired t test. Results In total, 128 children completed the study, n=65 in the DISC group and n=63 in the SV group. Myopia progressed 25% more slowly for children in the DISC group compared with those in the control group (0.30 D/year; 95% CI −0.71 to −0.47 vs 0.4 D/year; 95% CI −0.93 to −0.65, p=0.031). Likewise, there was less axial elongation for children in the DISC versus SV groups (0.13 mm/year; 95% CI 0.20 to 0.31 vs 0.18 mm/year; 95% CI 0.30 to 0.43, p=0.009). Treatment effect correlated positively with DISC lens wearing time (r=0.342; p=0.005). Indeed, myopia in children who wore the DISC lenses for five or more hours/day progressed 46% (mean difference=−0.382 D, p=0.001; 95% CI −0.59 to −0.17) less than those in the SV group. Conclusions The daily wearing of DISC lens significantly slowed myopia progression and axial elongation in Hong Kong schoolchildren. The findings demonstrated that simultaneous clear vision with constant myopic defocus can retard myopia progression.
Journal Article
Choroidal shift in myopic eyes in the 10-year follow-up Beijing eye study
by
Jonas, Rahul A.
,
Zhang, Qi
,
Wang, Ya Xing
in
692/698/1688/512/2613/1786
,
692/699
,
692/699/3161
2021
The aim of the study was to assess longitudinal changes in the spatial relationship of the choroidal vasculature to retinal vasculature in myopic eyes. In the population-based longitudinal Beijing Eye Study in 2001/2011, we examined all highly myopic eyes with assessable fundus photographs and a randomized group of non-highly myopic. Using fundus photographs, we qualitatively assessed changes in the location of major choroidal vessels in relationship to retinal vessels. The study consisted of 85 highly myopic eyes (58 participants;age:64.8 ± 9.4 years) and 85 randomly selected non-highly myopic eyes. A choroidal shift in relationship to the retinal vessels was detected more often in the highly myopic group than the non-highly myopic group (47/85 (55%) vs 6/85 (7%);
P
< 0.001). In the highly myopic group, the choroidal vessel shift occurring on the disc-fovea line in 39 (44%) eyes, was similar to, or smaller than, the enlargement in gamma zone width in 26 (67%) eyes and in 11 (28%) eyes respectively. The choroidal vessel shift was larger (
P
= 0.002) in eyes without choroidal vessels in gamma zone than in eyes with large choroidal vessels in gamma zone. In 14 (17%) eyes, a localized centrifugal choroidal shift was observed in association with an increase in the stage of myopic maculopathy. The results suggest that highly myopic eyes show a change in the position of large choroidal vessels in relationship to retinal vessels, in association with development or enlargement of gamma zone and an increase in the stage of myopic maculopathy.
Journal Article
The effect of pupil dilation on AL-Scan biometric parameters
by
Çetinkaya, Tuğba
,
Arıtürk, Nurşen
,
Duran, Mustafa
in
Adult
,
Anterior Chamber - physiology
,
Axial Length, Eye - drug effects
2016
The purpose of this study was to investigate the effects of pupil dilation on the parameters of the AL-Scan (Nidek Co., Ltd, Gamagori, Japan). We compared the measurements of axial length (AL), anterior chamber depth (ACD), central corneal keratometry reading, pupil diameter, and intraocular lens (IOL) power of 72 eyes of 72 healthy volunteers and patients scheduled for cataract surgery before and 45 min after instillation of cyclopentolate hydrochloride 1 % using the AL-Scan. Intraobserver repeatability was assessed by taking three consecutive recordings of ACD and AL. Only ACD readings were significantly different between predilation and postdilation (
P
< 0.001). The difference of the other measurements between two sessions was not statistically significant (
P
> 0.001). Only two cases in the study demonstrated changes in IOL power higher than 0.5 D. The intraobserver repeatability of both devices was good (CV values for ACD and AL were 0.16 and 0.20 %, respectively). Dilated pupil size did not affect the measurement of IOL power using the A-Scan optical biometer, but increase in ACD after dilation should be taken into account when performing refractive surgeries in which ACD is very important such as phakic anterior chamber IOL implantation.
Journal Article
Orthokeratology to Control Myopia Progression: A Meta-Analysis
by
Sun, Yuan
,
Zhang, Ting
,
Xu, Fan
in
Analysis
,
Axial Length, Eye - physiology
,
Care and treatment
2015
To evaluate the clinical treatment effects of orthokeratology to slow the progression of myopia.
Several well-designed controlled studies have investigated the effects of orthokeratology in school-aged children. We conducted this meta-analysis to better evaluate the existing evidence. Relevant studies were identified in the Medline and Embase database without language limitations. The main outcomes included axial length and vitreous chamber depth reported as the mean ± standard deviation. The results were pooled and assessed with a fixed-effects model analysis. Subgroup analyses were performed according to geographical location and study design.
Of the seven eligible studies, all reported axial length changes after 2 years, while two studies reported vitreous chamber depth changes. The pooled estimates indicated that change in axial length in the ortho-k group was 0.27 mm (95% confidence interval [CI]: 0.22, 0.32) less than the control group. Myopic progression was reduced by approximately 45%. The combined results revealed that the difference in vitreous chamber depth between the two groups was 0.22 mm (95% confidence interval [CI]: 0.14, 0.31). None of the studies reported severe adverse events.
The overall findings suggest that ortho-k can slow myopia progression in school-aged children.
Journal Article
Ocular biometry and refractive outcomes using two swept-source optical coherence tomography-based biometers with segmental or equivalent refractive indices
2019
This study compared the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), mean anterior corneal radius of curvature (Rm), and postoperative refractive outcomes obtained from two different swept-source optical coherence biometers, the ARGOS (Movu, Aichi, Japan), which uses the segmental refractive index for each segment, and the IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany), which uses an equivalent refractive index for the entire eye. One hundred and six eyes of 106 patients with cataracts were included. The refractive outcomes using the Barrett Universal II, Haigis, Hoffer Q, and SRK/T formulas were evaluated. The mean AL, CCT, ACD, and Rm differed significantly (P < 0.001) with the IOLMaster 700 (25.22 mm, 559 µm, 3.23 mm, and 7.69 mm) compared with the ARGOS (25.14 mm, 533 µm, 3.33 mm, and 7.66 mm). The mean LTs did not differ significantly. The percentages of eyes within ±0.50 and ±1.00 diopter of the predicted refraction did not differ significantly (P > 0.05). The accuracy of the intraocular lens power calculations was clinically acceptable with both biometers, although the ocular biometry using these two biometers exhibited certain differences.
Journal Article
Outdoor activity and myopia progression in 4-year follow-up of Chinese primary school children: The Beijing Children Eye Study
by
Feng, Yi
,
Xu, Liang
,
Tang, Ping
in
Axial Length, Eye - physiology
,
Beijing - epidemiology
,
Biology and Life Sciences
2017
To investigate factors associated with ocular axial elongation and myopia progression during a 4-year follow-up in primary school children in Beijing.
This school-based study included 382 grade-1 children at baseline in 2011 (age:6.3±0.4 years) with 305 (79.8%) returning for the follow-up examination in 2015. At baseline and in yearly follow-up examinations, the children underwent a comprehensive eye examination including auto-refractometry, ocular biometry with measurement of axial length, and fundus photography. The parents underwent a standardized interview.
During the study period, the mean axial length elongated by 1.15±0.56mm in boys and 1.10±0.63mm in girls. At baseline and at the end of follow-up, axial length was significantly (P<0.001) longer in boys, with no difference (P = 0.50) between genders in axial elongation. In multivariate analysis, greater axial elongation was associated (regression coefficient r2:0.15) with less time spent outdoors (P = 0.004; standardized coefficient beta: -0.22), more time spent indoors with studying (P = 0.02; beta: 0.18) and paternal myopia (P = 0.03; beta: 0.16). Larger increases in the axial length/anterior corneal curvature (AL/CC) ratio were associated (r2:0.09) with less time spent outdoors (PP = 0.003; beta: -0.22) and maternal myopia (PP = 0.02; beta: 0.18).
Myopic axial elongation during a 4-year follow-up was associated with shorter time spent outdoors and longer time spent indoors studying and with parental myopia. Other factors such as level of paternal education, family income, gender and region of habitation were significantly associated with axial elongation and with myopia progression only in univariate analysis.
Journal Article
Gene Therapy Restores Mfrp and Corrects Axial Eye Length
2017
Hyperopia (farsightedness) is a common and significant cause of visual impairment, and extreme hyperopia (nanophthalmos) is a consequence of loss-of-function
MFRP
mutations.
MFRP
deficiency causes abnormal eye growth along the visual axis and significant visual comorbidities, such as angle closure glaucoma, cystic macular edema, and exudative retinal detachment. The
Mfrp
rd6
/Mfrp
rd6
mouse is used as a pre-clinical animal model of retinal degeneration, and we found it was also hyperopic. To test the effect of restoring
Mfrp
expression, we delivered a wild-type
Mfrp
to the retinal pigmented epithelium (RPE) of
Mfrp
rd6
/Mfrp
rd6
mice via adeno-associated viral (AAV) gene therapy. Phenotypic rescue was evaluated using non-invasive, human clinical testing, including fundus auto-fluorescence, optical coherence tomography, electroretinography, and ultrasound. These analyses showed gene therapy restored retinal function and normalized axial length. Proteomic analysis of RPE tissue revealed rescue of specific proteins associated with eye growth and normal retinal and RPE function. The favorable response to gene therapy in
Mfrp
rd6
/Mfrp
rd6
mice suggests hyperopia and associated refractive errors may be amenable to AAV gene therapy.
Journal Article
Accuracy of intraocular lens power calculation using three optical biometry measurement devices: the OA-2000, Lenstar-LS900 and IOLMaster-500
2018
PurposeTo compare ocular measurements of three optical biometry devices and their application in intraocular lens (IOL) power calculations.MethodsOne hundred and forty eyes which had undergone cataract extraction surgery with preoperative biometry with OA-2000, IOLMaster-500, and Lenstar-LS900 were enrolled. Biometry measurements of the three devices were compared. The deviation of the postoperative refraction from the preoperative refractive target was calculated with different formulas (Barrett Universal II, Hoffer Q, Holladay I, and SRK/T). Errors in the predicted astigmatism using the Barrett toric calculator were calculated for the toric IOLs. Additional 6465 eyes in which the IOLMaster-500 failed to measure axial length (AL) were reviewed. The percentage of successful measurements using the OA-2000 in those eyes was calculated.ResultsHigh agreement was found between the three devices for AL, anterior chamber depth, and average keratometry measurements (interclass correlation confidents: 1.000, 0.970, and 0.998, respectively, P < 0.001). The mean absolute prediction errors were similar using all formulas, ranging from 0.25 to 0.29 D, with no statistical significant difference between the three devices per each formula. The OA-2000 yielded a lower against-the-rule (ATR) centroid error in the predicted astigmatism than the IOLMaster-500 and Lenstar-LS900 (0.06 D ± 0.59 at 13.4° vs. 0.20 D ± 0.61 at 14.8° and 0.16 D ± 0.55 at 21.4°, respectively, P < 0.001, X-axis). Among 301 cases with unsuccessful AL readings using the IOLMaster-500, the OA-2000 had 284 (94.35%) successful measurements.ConclusionsThe OA-2000 measurements showed good agreement with those of the IOLMaster-500 and Lenstar-LS900. Our results may suggest a potential advantage of the OA-2000 device in toric IOLs calculations and AL measurement success rate.
Journal Article
Puberty could regulate the effects of outdoor time on refractive development in Chinese children and adolescents
by
Zhao, Huijuan
,
Cheng, Tianyu
,
Wang, Jingjing
in
Adolescent
,
Asian Continental Ancestry Group - ethnology
,
Axial Length, Eye - physiology
2021
AimTo explore the impact of puberty on refractive development and its interaction with outdoor time in children and adolescents.MethodsIn this 2-year observational study, students aged 7–13 years were selected with cluster sampling. All participants underwent cycloplegic refraction and axial length measurements once every year. Information of related factors was acquired through proper questionnaire or inquiry. The level of testosterone/estradiol was detected from the saliva of the subjects using the ELISA kit. Multiple linear regression and generalised estimating equation (GEE) were used to analyse the relationship among puberty, outdoor activities and refractive indicators.ResultsA total of 776 children and adolescents were included, with an average baseline age of 9.64±1.54 years and 53.6% boys. There were 350 myopes (55.2% of the 634 cyclopleged subjects) at baseline. There was a significant difference in the mean axial length changes and outdoor time among different puberty groups (for axial length: p=0.017, for outdoor time: p=0.015). Myopic parents, less outdoor time and more changes in estradiol were associated with greater changes in axial length and spherical equivalent (SE) (axial length changes: parental myopia β=0.230, outdoor time β=−0.250, changes in estradiol β=0.261; SE changes: parental myopia β=−0.267, outdoor time β=0.256, changes in estradiol β=−0.297). In the GEE model, the interaction between outdoor time and puberty was significantly associated with axial length (p=0.024, β=1.199).ConclusionsThis study implies puberty may play a regulating role on the relationship between outdoor time and refractive development among Chinese children and adolescents, which provides clues for in-depth mechanism interpretation and efficient intervention strategies.
Journal Article
The distribution of retinal nerve fiber layer thickness and associations with age, refraction, and axial length: the Gutenberg health study
2018
PurposeTo evaluate the distribution of peripapillary retinal nerve fiber layer thickness as measured by optical coherence tomography and its associations with ocular parameters in a population-based setting.MethodsIn the population-based Gutenberg Health Study, 1974 subjects from the Mainz-Bingen region were scheduled for ophthalmologic examinations, including visual acuity, refraction, tonometry, biometry, and measurements of peripapillary retinal nerve fiber layer thickness (pRNFL) by optical coherence tomography (SD-OCT, Spectralis®, Heidelberg Engineering, Germany). The associated factors in the global and sectoral pRNFL data were analyzed using multivariable linear mixed models related to age, sex, and ocular parameters.ResultsAdvanced age and longer axial length were associated with a thinner pRNFL, whereas pRNFL thickness was independent of sex, intraocular pressure (IOP), and central corneal thickness (CCT). Spherical equivalent was positively associated with pRNFL thickness, except in the temporal pRNFL sector.ConclusionsIn this large, population-based study, pRNFL thickness decreased with age. Longer eyes had thinner pRNFL thickness. Sex, IOP, and CCT showed no significant association with pRNFL thickness. These data may improve the interpretation of pRNFL data.
Journal Article