AIM:To investigate the prevalence of visual impairment(VI)and provide an estimation of uncorrected refractive errors in school-aged children,conducted by optometry students as a community service.METHODS:The study was...AIM:To investigate the prevalence of visual impairment(VI)and provide an estimation of uncorrected refractive errors in school-aged children,conducted by optometry students as a community service.METHODS:The study was cross-sectional.Totally 3343 participants were included in the study.The initial examination involved assessing the uncorrected distance visual acuity(UDVA)and visual acuity(VA)while using a+2.00 D lens.The inclusion criteria for a subsequent comprehensive cycloplegic eye examination,performed by an optometrist,were as follows:a UDVA<0.6 decimal(0.20 logMAR)and/or a VA with+2.00 D≥0.8 decimal(0.96 logMAR).RESULTS:The sample had a mean age of 10.92±2.13y(range 4 to 17y),and 51.3%of the children were female(n=1715).The majority of the children(89.7%)fell within the age range of 8 to 14y.Among the ethnic groups,the highest representation was from the Luhya group(60.6%)followed by Luo(20.4%).Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17(range 1.70 to 0.22).Out of the total,246 participants(7.4%)had a full eye examination.The estimated prevalence of myopia(defined as spherical equivalent≤-0.5 D)was found to be 1.45%of the total sample.While around 0.18%of the total sample had hyperopia value exceeding+1.75 D.Refractive astigmatism(cil<-0.75 D)was found in 0.21%(7/3343)of the children.The VI prevalence was 1.26%of the total sample.Among our cases of VI,76.2%could be attributed to uncorrected refractive error.Amblyopia was detected in 0.66%(22/3343)of the screened children.There was no statistically significant correlation observed between age or gender and refractive values.CONCLUSION:The primary cause of VI is determined to be uncorrected refractive errors,with myopia being the most prevalent refractive error observed.These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.展开更多
Purpose:The aim of this paper was to examine the distribution of macular,retinal nerve fiber layer(RNFL)thickness and optic disc parameters of myopic and hyperopic eyes in comparison withemmetropic control eyes and to...Purpose:The aim of this paper was to examine the distribution of macular,retinal nerve fiber layer(RNFL)thickness and optic disc parameters of myopic and hyperopic eyes in comparison withemmetropic control eyes and to investigate their variation according to axial length(AL)andspherical equivalent(SE)in healthy children.Methods:This study included 293 pairs of eyes of 293children(145 boys and 148 girks),ranging in age from 6 to 17 years,Subjects were dividedaccording to SE in control(emmetropia,99 children),myopia(100 children)and hyperopia(94children)groups and according to axial AL in 68 short(<22.00 mm,68),medium(from≥22.00 mmto 25.00 mm,189)and long eyes(>25.00 mm,36).Macular parameters,RNFL thickness and opticdisc morphology were assessed by the Cirrus^(TM) HD-OCT.AL was measured using the IOL-Mastersystem.Littmann's formula was used for calculating the corrected AL-related ocular magnification.Results Mean age(±SD)was 10.84±3.05 years;mean(±SD)SE was+0.14±0.51 D(range from8.75 to+8.25 D)and mean AL(±SD)was 23.12±1.49.Average RNFL thickness,averagemacular thickness and macular volume decreased as AL and myopia increased.No correlationsbetween AL/SE and optic disc parameters were found after correcting for magnification effect.Conclusions:AL and refractive error affect measurements of macular and RNFL thickness inhealthy children.To make a correct interpretation of ocT measurements,ocular magnificationeffect should be taken into account by clinicians or OCT manufacturers.展开更多
AIM： To investigate the potential effect that odd and even-order monochromatic aberrations may have on the accommodation response of the human eye. METHODS： Eight healthy subjects with astigmatism below 1 D, best c...AIM： To investigate the potential effect that odd and even-order monochromatic aberrations may have on the accommodation response of the human eye. METHODS： Eight healthy subjects with astigmatism below 1 D, best corrected visual acuity 20/20 or better and normal findings in an ophthalmic examination were enrolled. An adaptive optics system was used in order to measure the accommodation response of the subjects＇ eyes under different conditions： with the natural aber- rations being present, and with the odd and even-order aberrations being corrected. Three measurements of accommodation response were monocularly acquired at accommodation demands ranging from 0 to 4 D （0.5 D step）. RESULTS： The accommodative lag was greater for the accommodate demands of 1.5, 3, 3.5 and 4 D for the condition in which the even-order aberrations were corrected, in comparison to that obtained for the natural aberrations and corrected odd-order aberrations for the same accommodation demands. No statistically significant differences were found between the accommodation responses under the three conditions. CONCLUSION： The odd and even-order aberrations are not helping the visual system to accommodate, because their partial correction do not affect the accommodation performance.展开更多
The use of adaptive optics systems in ophthalmic research studies has increased in the last years thanks to the development of more accurate devices.Adaptive optics was first introduced in Astronomy for the correction...The use of adaptive optics systems in ophthalmic research studies has increased in the last years thanks to the development of more accurate devices.Adaptive optics was first introduced in Astronomy for the correction of the effects produced by the turbulences of the Earth’s atmosphere when observing astronomical objects(1,2).Sophisticated deformable mirrors controlled by computers can correct in real time atmospheric disturbances,allowing for much finer details on the images of distance objects.Adaptive optics technology makes it possible to correct many of the aberrations with which the wavefront,i.e.,the geometric envelope of all the rays of light that emerged at the same time of the observed object,arrives.Adaptive optics allows for obtaining sharper images,and thus,with better spatial resolution.展开更多
Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5...Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5.00 D)in terms of sphere,astigmatism,and spherical equivalent refraction.Methods:Refraction was measured at the center,20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field,binocular,infrared autorefractor(Grand Seiko WAM-5500,Hiroshima,Japan).Fixation target was a Maltese cross set at 2.00,0.50,0.33 and 0.20 m from the corneal plane.Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.Results:Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance.Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group.This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.Conclusion:Accommodation to very near targets(up to 0.20 m)makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes.A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.展开更多
AIM:To compare the visual perception(color and chromatic-achromatic contrast vision)of a small cohort of COVID-19 patients at the time of infection and after 6mo with that of a healthy population matched for sex and a...AIM:To compare the visual perception(color and chromatic-achromatic contrast vision)of a small cohort of COVID-19 patients at the time of infection and after 6mo with that of a healthy population matched for sex and age.METHODS:A total of 25 patients(9 females,16 males,mean age:54±10y)with COVID-19 hospitalized in the COVID-19 Unit of the University Clinical Hospital of Valladolid were recruited for this preliminary study.Visual perception,as determined by monocular measurement of contrast sensitivity function(CSF)and color vision was assessed in each patient using the Optopad test.The results obtained were then compared with those of a sample of 16 age-and sex-matched healthy controls(5 females,11 males,mean age:50±6y)in which the same measurement procedure was repeated.Statistically significant differences between groups were assessed using the Mann-Whitney U test.Measurements were repeated after a minimum follow-up period of 6mo and statistically significant differences between the two time points in each group were assessed using the Wilcoxon signed rank test.RESULTS:Discrimination thresholds(color and chromatic-achromatic contrast vision)and their corresponding sensitivity,calculated as the inverse of the discrimination threshold,were evaluated.Analysis of the data revealed higher contrast threshold results(i.e.,worse contrast sensitivity)in the COVID-19 group than in the control group for all spatial frequencies studied in the Optopad-CSF achromatic test and most of the spatial frequencies studied in the Optopad-CSF chromatic test for the red-green and blue-yellow mechanisms.In addition,color threshold results in the COVID-19 group were also significantly higher(i.e.,worse color sensitivity)for almost all color mechanisms studied in the Optopad-Color test.At 6mo,most of the differences found between the groups were maintained despite COVID-19 recovery.CONCLUSION:The present results provide preliminary evidence that visual perception may be impaired in COVID-19,even when the infection has passed.Although further research is needed to determine the precise causes of this finding,analysis of CSF and color vision could provide valuable information on the visual impact of COVID-19.展开更多
One of the most important developments in the ophthalmology and visual sciences field has been the application of new techniques for imaging the anterior and posterior segment of the eye with non-contact devices.These...One of the most important developments in the ophthalmology and visual sciences field has been the application of new techniques for imaging the anterior and posterior segment of the eye with non-contact devices.These techniques have been developed quickly considering that are non-invasive and provide high-resolution images of the different parts of the human eye.Definitely,the most spread and used technique for non-contact imaging of the human eye is the optical coherence tomography(OCT).OCT technique was first demonstrated in 1991 by Huang et al.(1).展开更多
文摘AIM:To investigate the prevalence of visual impairment(VI)and provide an estimation of uncorrected refractive errors in school-aged children,conducted by optometry students as a community service.METHODS:The study was cross-sectional.Totally 3343 participants were included in the study.The initial examination involved assessing the uncorrected distance visual acuity(UDVA)and visual acuity(VA)while using a+2.00 D lens.The inclusion criteria for a subsequent comprehensive cycloplegic eye examination,performed by an optometrist,were as follows:a UDVA<0.6 decimal(0.20 logMAR)and/or a VA with+2.00 D≥0.8 decimal(0.96 logMAR).RESULTS:The sample had a mean age of 10.92±2.13y(range 4 to 17y),and 51.3%of the children were female(n=1715).The majority of the children(89.7%)fell within the age range of 8 to 14y.Among the ethnic groups,the highest representation was from the Luhya group(60.6%)followed by Luo(20.4%).Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17(range 1.70 to 0.22).Out of the total,246 participants(7.4%)had a full eye examination.The estimated prevalence of myopia(defined as spherical equivalent≤-0.5 D)was found to be 1.45%of the total sample.While around 0.18%of the total sample had hyperopia value exceeding+1.75 D.Refractive astigmatism(cil<-0.75 D)was found in 0.21%(7/3343)of the children.The VI prevalence was 1.26%of the total sample.Among our cases of VI,76.2%could be attributed to uncorrected refractive error.Amblyopia was detected in 0.66%(22/3343)of the screened children.There was no statistically significant correlation observed between age or gender and refractive values.CONCLUSION:The primary cause of VI is determined to be uncorrected refractive errors,with myopia being the most prevalent refractive error observed.These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.
文摘Purpose:The aim of this paper was to examine the distribution of macular,retinal nerve fiber layer(RNFL)thickness and optic disc parameters of myopic and hyperopic eyes in comparison withemmetropic control eyes and to investigate their variation according to axial length(AL)andspherical equivalent(SE)in healthy children.Methods:This study included 293 pairs of eyes of 293children(145 boys and 148 girks),ranging in age from 6 to 17 years,Subjects were dividedaccording to SE in control(emmetropia,99 children),myopia(100 children)and hyperopia(94children)groups and according to axial AL in 68 short(<22.00 mm,68),medium(from≥22.00 mmto 25.00 mm,189)and long eyes(>25.00 mm,36).Macular parameters,RNFL thickness and opticdisc morphology were assessed by the Cirrus^(TM) HD-OCT.AL was measured using the IOL-Mastersystem.Littmann's formula was used for calculating the corrected AL-related ocular magnification.Results Mean age(±SD)was 10.84±3.05 years;mean(±SD)SE was+0.14±0.51 D(range from8.75 to+8.25 D)and mean AL(±SD)was 23.12±1.49.Average RNFL thickness,averagemacular thickness and macular volume decreased as AL and myopia increased.No correlationsbetween AL/SE and optic disc parameters were found after correcting for magnification effect.Conclusions:AL and refractive error affect measurements of macular and RNFL thickness inhealthy children.To make a correct interpretation of ocT measurements,ocular magnificationeffect should be taken into account by clinicians or OCT manufacturers.
基金Supported by the Marie Curie Grant FP7-LIFEITN-2013-608049-AGEYE Grantthe Atraccióde Talent(University of Valencia)Research Scholarship(UV-INVPREDOC14-179135)
文摘AIM： To investigate the potential effect that odd and even-order monochromatic aberrations may have on the accommodation response of the human eye. METHODS： Eight healthy subjects with astigmatism below 1 D, best corrected visual acuity 20/20 or better and normal findings in an ophthalmic examination were enrolled. An adaptive optics system was used in order to measure the accommodation response of the subjects＇ eyes under different conditions： with the natural aber- rations being present, and with the odd and even-order aberrations being corrected. Three measurements of accommodation response were monocularly acquired at accommodation demands ranging from 0 to 4 D （0.5 D step）. RESULTS： The accommodative lag was greater for the accommodate demands of 1.5, 3, 3.5 and 4 D for the condition in which the even-order aberrations were corrected, in comparison to that obtained for the natural aberrations and corrected odd-order aberrations for the same accommodation demands. No statistically significant differences were found between the accommodation responses under the three conditions. CONCLUSION： The odd and even-order aberrations are not helping the visual system to accommodate, because their partial correction do not affect the accommodation performance.
基金Authors acknowledge financial support from the Starting Grant Project ERC-2012-StG-309416(European Research Council).
文摘The use of adaptive optics systems in ophthalmic research studies has increased in the last years thanks to the development of more accurate devices.Adaptive optics was first introduced in Astronomy for the correction of the effects produced by the turbulences of the Earth’s atmosphere when observing astronomical objects(1,2).Sophisticated deformable mirrors controlled by computers can correct in real time atmospheric disturbances,allowing for much finer details on the images of distance objects.Adaptive optics technology makes it possible to correct many of the aberrations with which the wavefront,i.e.,the geometric envelope of all the rays of light that emerged at the same time of the observed object,arrives.Adaptive optics allows for obtaining sharper images,and thus,with better spatial resolution.
基金supported by Strategic Project PEST-C/FIS/UI607/2011 from the Science and Technology Foundation of Portuguese Ministry of Science and Higher Education.
文摘Purpose:To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m(0.50 D)to 0.20 m(5.00 D)in terms of sphere,astigmatism,and spherical equivalent refraction.Methods:Refraction was measured at the center,20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field,binocular,infrared autorefractor(Grand Seiko WAM-5500,Hiroshima,Japan).Fixation target was a Maltese cross set at 2.00,0.50,0.33 and 0.20 m from the corneal plane.Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.Results:Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance.Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group.This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.Conclusion:Accommodation to very near targets(up to 0.20 m)makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes.A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.
基金Supported by the Institute of Health CarlosⅢ(No.COV20/00539)。
文摘AIM:To compare the visual perception(color and chromatic-achromatic contrast vision)of a small cohort of COVID-19 patients at the time of infection and after 6mo with that of a healthy population matched for sex and age.METHODS:A total of 25 patients(9 females,16 males,mean age:54±10y)with COVID-19 hospitalized in the COVID-19 Unit of the University Clinical Hospital of Valladolid were recruited for this preliminary study.Visual perception,as determined by monocular measurement of contrast sensitivity function(CSF)and color vision was assessed in each patient using the Optopad test.The results obtained were then compared with those of a sample of 16 age-and sex-matched healthy controls(5 females,11 males,mean age:50±6y)in which the same measurement procedure was repeated.Statistically significant differences between groups were assessed using the Mann-Whitney U test.Measurements were repeated after a minimum follow-up period of 6mo and statistically significant differences between the two time points in each group were assessed using the Wilcoxon signed rank test.RESULTS:Discrimination thresholds(color and chromatic-achromatic contrast vision)and their corresponding sensitivity,calculated as the inverse of the discrimination threshold,were evaluated.Analysis of the data revealed higher contrast threshold results(i.e.,worse contrast sensitivity)in the COVID-19 group than in the control group for all spatial frequencies studied in the Optopad-CSF achromatic test and most of the spatial frequencies studied in the Optopad-CSF chromatic test for the red-green and blue-yellow mechanisms.In addition,color threshold results in the COVID-19 group were also significantly higher(i.e.,worse color sensitivity)for almost all color mechanisms studied in the Optopad-Color test.At 6mo,most of the differences found between the groups were maintained despite COVID-19 recovery.CONCLUSION:The present results provide preliminary evidence that visual perception may be impaired in COVID-19,even when the infection has passed.Although further research is needed to determine the precise causes of this finding,analysis of CSF and color vision could provide valuable information on the visual impact of COVID-19.
基金The authors acknowledge financial support from the Ministerio de Economía y Competitivad(Research Project SAF2013-44510-R with FEDER Funds).
文摘One of the most important developments in the ophthalmology and visual sciences field has been the application of new techniques for imaging the anterior and posterior segment of the eye with non-contact devices.These techniques have been developed quickly considering that are non-invasive and provide high-resolution images of the different parts of the human eye.Definitely,the most spread and used technique for non-contact imaging of the human eye is the optical coherence tomography(OCT).OCT technique was first demonstrated in 1991 by Huang et al.(1).
