Medical Hypothesis, Discovery & Innovation in Optometry, 2021
Background: Measuring contrast sensitivity (CS) allows a better understanding of the visual perfo... more Background: Measuring contrast sensitivity (CS) allows a better understanding of the visual performance of the human eye. This study aimed to examine the correlation and agreement between the results of two sinewave grating-based CS measurement methods, Metrovision and CSV-1000, in normal eyes. Methods: This cross-sectional, comparative study was performed between December 2018 and April 2019, at an optometry clinic. Subjects underwent comprehensive ocular examinations, which included pupil reflexes, subjective refraction, external eye examinations, smooth pursuit eye movement assessment, the cover–uncover test, and detailed slit-lamp examination of the anterior and posterior segments. Metrovision and CSV-1000 were employed to assess CS under photopic conditions. The correlation and agreement of the results of the two tests were evaluated. Results: CS was measured for 104 normal eyes for 3, 6, 12, and 18 cycles per degree (cpd) spatial frequencies (participants’ mean age ± standard ...
ABSTRACT Purpose To determine the prevalence and risk factors of refractive errors among schoolch... more ABSTRACT Purpose To determine the prevalence and risk factors of refractive errors among schoolchildren in Bojnourd, Iran.Methods In a cross-sectional study using random cluster sampling, 2020 schoolchildren 6 to 17 years of age were selected in this study. The participants totaled 1551; 643 boys and 908 girls of the elementary and middle schoolchildren of Bojnourd, northeast of Iran. Mean age of the participants was 11.2 years (response rate=76.7%). Refractive errors were measured under cycloplegia. Myopia defined as spherical equivalent (SE) refraction - 0.5 dioptre (D) or worse, hyperopia as SE +2.00 D or more, and astigmatism as cylinder -0.75 D or worse.Results The prevalence of myopia, hyperopia and astigmatism were 4.3%, 5.4% and 11.5% respectively and were not related to the gender. The prevalence of myopia and against-the-rule astigmatism increased with age (p<0.001).Conclusion The results of this study showed that the prevalence of myopia in schoolchildren of Bojnourd was similar to that in most places excluding East Asian countries, and that of hyperopia and astigmatism were in the mid range.
Purpose To determine the prevalence of anisometropia, amblyopia and starbimus in schoolchildren o... more Purpose To determine the prevalence of anisometropia, amblyopia and starbimus in schoolchildren of Bojnourd, Iran. Methods A random cluster sampling was used in a cross-sectional study on 2020 schoolchildren in Bojnourd, northeast of Iran. The participants totaled 1551; 643 boys and 908 girls. Mean age of the partipiciants was 11.12 years (respose rate= 76.7%). Examinations included: uncorrected and best corrected visual acuity (UCVA and BCVA) measurements, cycloplegic refraction and cover test. Anisometropia ...
PURPOSE Under real-world conditions, tasks dependent on visual acuity may need to be performed in... more PURPOSE Under real-world conditions, tasks dependent on visual acuity may need to be performed in the presence of a mental load arising from concurrent, non-visual tasks. Therefore, measuring visual acuity concurrently with mentally demanding tasks may reflect a patient's vision more accurately. This study was designed to evaluate the impact of task-induced mental load on high contrast visual acuity, as measured using a letter chart and estimated via sweep visual evoked potentials (sweep VEP). METHODS Visual acuity was determined using the Freiburg Vision Test, and also using sweep VEP tested stepwise, from coarse to fine, over 13 spatial frequencies, in 31 healthy participants (aged 22.4 ± 3.6 years). Recordings were repeated while participants concurrently performed an auditory 2-back task. Mental load of the n-back task was confirmed through subjective ratings. RESULTS Visual acuity determined with the Freiburg Vision Test worsened from -0.02 ± 0.12 to 0.04 ± 0.15 logMAR under mental load (p = 0.03). Visual acuities estimated by sweep VEPs worsened from 0.38 ± 0.1 to 0.47 ± 0.1 logMAR (p < 0.001). While the slope of the VEP amplitude versus spatial frequency function steepened significantly with mental load (p = 0.01), VEP noise levels were not significantly affected (p = 0.07). CONCLUSION Visual acuity reduces significantly with a concurrent task that produces mental load. At least part of this reduction appears to be related to alterations in responses within the visual cortex, rather than being purely attributable to higher-level distraction effects.
Background and Objective: In general, understanding and willingness to act toward a certain thing... more Background and Objective: In general, understanding and willingness to act toward a certain thing is called the attitude toward that thing. Individuals� attitudes change in different periods of life according to their environment. One of the stages of life that has the most change of attitude and interest is the period of studying. This research was conducted to survey the attitude of optometric students about their field of study. Methods: This cross-sectional descriptive-analytical study was performed on all optometric undergraduate students at Mashhad University of Medical Sciences using a census method in the academic year of 2016-2017. Of the total of 88 students, 2 of them did not respond to the questionnaire. The data on a total of 86 people were gathered. The data gathering method was a questionnaire which had been evaluated for reliability and validity. Questionnaire questions were scored based on three-point Likert scale. Data were analyzed by SPSS version 22 using descr...
Introduction: The aim of present study was to assess the correlation between glucose and lipid bi... more Introduction: The aim of present study was to assess the correlation between glucose and lipid biomarkers variations with biometric characteristics and intraocular pressure changes following Ramadan fasting. Methods: A total of 100 healthy fasting volunteers were enrolled in the study. Of them, 89 subjects completed the study with respect to inclusion and exclusion criteria. Right eye ocular axial length and anterior chamber depth were determined using the IOLMaster, (Carl Zeiss Meditec, Jena, Germany). Following that, intraocular pressure of right eye was measured using a non-contact tonometer (Topcon, Computerized Tonometer CT-1/CT-1P, Tokyo, Japan). Blood samples were taken from all the participants and concentrations of the biomarkers, including Fast blood sugar, Triglyceride, Cholesterol, High-density lipoprotein and Low-density lipoprotein were measured using the Hitachi 717 analyzer (Hitachi, Tokyo, Japan). All assessments were obtained one week before and after Ramadan. Resu...
Introduction This study aimed to investigate the effect of phacoemulsification on macular thickne... more Introduction This study aimed to investigate the effect of phacoemulsification on macular thickness and volume in diabetic patients without retinopathy using optical coherence tomography (OCT).Methods This prospective study included 37 diabetics and 55 non-diabetic patients (n=92) with cataract who were scheduled for phacoemulsification. The participants were entered into the study based on the inclusion and exclusion criteria following a complete eye examination. Macular thickness and volume were measured preoperatively as well as one month postoperatively using the OCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany).Results The present study analyzed 76 eyes of 76 patients with immature cataract. No significant differences were observed between diabetic and non-diabetic groups in terms of thickness and volume in the macular area. However, the results showed a significant increase in both groups regarding the thickness and volume after phacoemulsification. Conclusion The ...
Introduction: The present study aimed to assess the effects of Ramadan fasting on micronutrients ... more Introduction: The present study aimed to assess the effects of Ramadan fasting on micronutrients and their correlations with ocular biometry. Methods: This prospective study was conducted on 89 healthy volunteers (51 males and 38 females) with the mean of 34.98±9.10 years in Mashhad, Iran. Participants received complete ophthalmic and systemic examinations one week before and one week after the holy month of Ramadan in 2015. Subjects with no history of systemic and ophthalmic diseases were enrolled in the study. Blood samples were obtained from all the participants in the morning in both phases of the study. Levels of micronutrients were measured in the blood samples using the Hitachi 717 analyzer (Hitachi, Japan). In addition, IOLMaster (Carl Zeiss Meditec AG, Germany) was applied to determine the ocular axial length (AL) and anterior chamber depth (ACD). Results: No significant differences were observed in the AL and ACD of the subjects before and after Ramadan fasting (P>0.05)...
We thank Dr. Prousali Efthymia et al. for their perceptive comments on our research. Their letter... more We thank Dr. Prousali Efthymia et al. for their perceptive comments on our research. Their letter concerned primarily regarding the trend of choroidal thickness changes during childhood. The main objective of our study was to characterize the distribution of choroidal thickness profile in healthy Iranian children and adults at different age groups from 4 to 60 years old.1 The different kinds of refractive errors were labeled for each age group. The purpose of the study necessitated performing the examinations on a large sample of subjects from childhood to adulthood with different types of refractive errors. One limitation of our study was that we could not easily find a large number of children up to 10‐year‐old with different types of refractive errors to include in the study. However, considering the poor cooperation of children in the prolonged process of examinations and compared with previous studies, the number of pediatric subjects in the present study seems to be reasonable...
Introduction: This article aimed to review the literatures on visual impairments and ocular chang... more Introduction: This article aimed to review the literatures on visual impairments and ocular changes in premature infants with low birth weight and gestational age.Methods: Five electronic databases including: PubMed, Web of Science, Science direct, Ovid, and Scopus were searched. Original articles published until 2015 describing preterm infants were reviewed. Repetitive and derivative articles were excluded.Results: Out of 100 unique, potentially relevant articles, 42 studies that addressed and met the inclusion criteria were evaluated.Conclusion: Prematurity affects ocular structures (from anterior to posterior segment) and functions. Premature infants are at risk of myopization. Concerning the changes in premature infants, a significant increase is found in axial length, intraocular pressure, and central corneal thickness; moreover, high incidence of retinal changes is reported as a result of prematurity. On the other hand, visual acuity, tear, electroretinogram, and visual evoked...
Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the... more Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods Articles included in the study were taken from PubMed, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals on fasting and vision system. Results Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thicknesses, and also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion Much research related to the effect of dehydration on ocular parameters during Ramadan fasting exists. The findings reveal association with significant changes on ocular parameters. Thus, it seems requisite to have a comprehensive study on "fasting and ocular parameters”, which will be helpful in making decisions and giving plan ...
ABSTRACT Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland... more ABSTRACT Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland dysfunction (MGD) and evaluate its risk factors by gender, age, and ethnicity. Methods: Articles were searched reporting the prevalence of MGD from PubMed, Scopus, Web of Science, and Embase databases. Results: The estimated pooled prevalence of MGD was 0.358 (95% CI 0.26–0.46; I 2: 99.57%). The prevalence of MGD was 0.358 (95% CI 0.24–0.50) in clinical and 0.359 (95% CI 0.22–0.52) in population-based studies. Men were more prone to MGD than women (OR: 1.24, 95% CI 1.01–1.52, p = 0.034). The rate of MGD was between 21.2% and 29.5% in Africans and Caucasians, to 71.0% in Arabs, and 67.5% in Hispanics. Conclusion: MGD is a quite prevalent disorder with an estimated pooled prevalence of 35.8%. Men are more prone to MGD than women. There is a large variation between studies in terms of quality, sample size, age ranges, diagnostic criteria, and ethnicity.
Medical Hypothesis, Discovery & Innovation in Optometry, 2021
Background: Measuring contrast sensitivity (CS) allows a better understanding of the visual perfo... more Background: Measuring contrast sensitivity (CS) allows a better understanding of the visual performance of the human eye. This study aimed to examine the correlation and agreement between the results of two sinewave grating-based CS measurement methods, Metrovision and CSV-1000, in normal eyes. Methods: This cross-sectional, comparative study was performed between December 2018 and April 2019, at an optometry clinic. Subjects underwent comprehensive ocular examinations, which included pupil reflexes, subjective refraction, external eye examinations, smooth pursuit eye movement assessment, the cover–uncover test, and detailed slit-lamp examination of the anterior and posterior segments. Metrovision and CSV-1000 were employed to assess CS under photopic conditions. The correlation and agreement of the results of the two tests were evaluated. Results: CS was measured for 104 normal eyes for 3, 6, 12, and 18 cycles per degree (cpd) spatial frequencies (participants’ mean age ± standard ...
ABSTRACT Purpose To determine the prevalence and risk factors of refractive errors among schoolch... more ABSTRACT Purpose To determine the prevalence and risk factors of refractive errors among schoolchildren in Bojnourd, Iran.Methods In a cross-sectional study using random cluster sampling, 2020 schoolchildren 6 to 17 years of age were selected in this study. The participants totaled 1551; 643 boys and 908 girls of the elementary and middle schoolchildren of Bojnourd, northeast of Iran. Mean age of the participants was 11.2 years (response rate=76.7%). Refractive errors were measured under cycloplegia. Myopia defined as spherical equivalent (SE) refraction - 0.5 dioptre (D) or worse, hyperopia as SE +2.00 D or more, and astigmatism as cylinder -0.75 D or worse.Results The prevalence of myopia, hyperopia and astigmatism were 4.3%, 5.4% and 11.5% respectively and were not related to the gender. The prevalence of myopia and against-the-rule astigmatism increased with age (p&lt;0.001).Conclusion The results of this study showed that the prevalence of myopia in schoolchildren of Bojnourd was similar to that in most places excluding East Asian countries, and that of hyperopia and astigmatism were in the mid range.
Purpose To determine the prevalence of anisometropia, amblyopia and starbimus in schoolchildren o... more Purpose To determine the prevalence of anisometropia, amblyopia and starbimus in schoolchildren of Bojnourd, Iran. Methods A random cluster sampling was used in a cross-sectional study on 2020 schoolchildren in Bojnourd, northeast of Iran. The participants totaled 1551; 643 boys and 908 girls. Mean age of the partipiciants was 11.12 years (respose rate= 76.7%). Examinations included: uncorrected and best corrected visual acuity (UCVA and BCVA) measurements, cycloplegic refraction and cover test. Anisometropia ...
PURPOSE Under real-world conditions, tasks dependent on visual acuity may need to be performed in... more PURPOSE Under real-world conditions, tasks dependent on visual acuity may need to be performed in the presence of a mental load arising from concurrent, non-visual tasks. Therefore, measuring visual acuity concurrently with mentally demanding tasks may reflect a patient's vision more accurately. This study was designed to evaluate the impact of task-induced mental load on high contrast visual acuity, as measured using a letter chart and estimated via sweep visual evoked potentials (sweep VEP). METHODS Visual acuity was determined using the Freiburg Vision Test, and also using sweep VEP tested stepwise, from coarse to fine, over 13 spatial frequencies, in 31 healthy participants (aged 22.4 ± 3.6 years). Recordings were repeated while participants concurrently performed an auditory 2-back task. Mental load of the n-back task was confirmed through subjective ratings. RESULTS Visual acuity determined with the Freiburg Vision Test worsened from -0.02 ± 0.12 to 0.04 ± 0.15 logMAR under mental load (p = 0.03). Visual acuities estimated by sweep VEPs worsened from 0.38 ± 0.1 to 0.47 ± 0.1 logMAR (p < 0.001). While the slope of the VEP amplitude versus spatial frequency function steepened significantly with mental load (p = 0.01), VEP noise levels were not significantly affected (p = 0.07). CONCLUSION Visual acuity reduces significantly with a concurrent task that produces mental load. At least part of this reduction appears to be related to alterations in responses within the visual cortex, rather than being purely attributable to higher-level distraction effects.
Background and Objective: In general, understanding and willingness to act toward a certain thing... more Background and Objective: In general, understanding and willingness to act toward a certain thing is called the attitude toward that thing. Individuals� attitudes change in different periods of life according to their environment. One of the stages of life that has the most change of attitude and interest is the period of studying. This research was conducted to survey the attitude of optometric students about their field of study. Methods: This cross-sectional descriptive-analytical study was performed on all optometric undergraduate students at Mashhad University of Medical Sciences using a census method in the academic year of 2016-2017. Of the total of 88 students, 2 of them did not respond to the questionnaire. The data on a total of 86 people were gathered. The data gathering method was a questionnaire which had been evaluated for reliability and validity. Questionnaire questions were scored based on three-point Likert scale. Data were analyzed by SPSS version 22 using descr...
Introduction: The aim of present study was to assess the correlation between glucose and lipid bi... more Introduction: The aim of present study was to assess the correlation between glucose and lipid biomarkers variations with biometric characteristics and intraocular pressure changes following Ramadan fasting. Methods: A total of 100 healthy fasting volunteers were enrolled in the study. Of them, 89 subjects completed the study with respect to inclusion and exclusion criteria. Right eye ocular axial length and anterior chamber depth were determined using the IOLMaster, (Carl Zeiss Meditec, Jena, Germany). Following that, intraocular pressure of right eye was measured using a non-contact tonometer (Topcon, Computerized Tonometer CT-1/CT-1P, Tokyo, Japan). Blood samples were taken from all the participants and concentrations of the biomarkers, including Fast blood sugar, Triglyceride, Cholesterol, High-density lipoprotein and Low-density lipoprotein were measured using the Hitachi 717 analyzer (Hitachi, Tokyo, Japan). All assessments were obtained one week before and after Ramadan. Resu...
Introduction This study aimed to investigate the effect of phacoemulsification on macular thickne... more Introduction This study aimed to investigate the effect of phacoemulsification on macular thickness and volume in diabetic patients without retinopathy using optical coherence tomography (OCT).Methods This prospective study included 37 diabetics and 55 non-diabetic patients (n=92) with cataract who were scheduled for phacoemulsification. The participants were entered into the study based on the inclusion and exclusion criteria following a complete eye examination. Macular thickness and volume were measured preoperatively as well as one month postoperatively using the OCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany).Results The present study analyzed 76 eyes of 76 patients with immature cataract. No significant differences were observed between diabetic and non-diabetic groups in terms of thickness and volume in the macular area. However, the results showed a significant increase in both groups regarding the thickness and volume after phacoemulsification. Conclusion The ...
Introduction: The present study aimed to assess the effects of Ramadan fasting on micronutrients ... more Introduction: The present study aimed to assess the effects of Ramadan fasting on micronutrients and their correlations with ocular biometry. Methods: This prospective study was conducted on 89 healthy volunteers (51 males and 38 females) with the mean of 34.98±9.10 years in Mashhad, Iran. Participants received complete ophthalmic and systemic examinations one week before and one week after the holy month of Ramadan in 2015. Subjects with no history of systemic and ophthalmic diseases were enrolled in the study. Blood samples were obtained from all the participants in the morning in both phases of the study. Levels of micronutrients were measured in the blood samples using the Hitachi 717 analyzer (Hitachi, Japan). In addition, IOLMaster (Carl Zeiss Meditec AG, Germany) was applied to determine the ocular axial length (AL) and anterior chamber depth (ACD). Results: No significant differences were observed in the AL and ACD of the subjects before and after Ramadan fasting (P>0.05)...
We thank Dr. Prousali Efthymia et al. for their perceptive comments on our research. Their letter... more We thank Dr. Prousali Efthymia et al. for their perceptive comments on our research. Their letter concerned primarily regarding the trend of choroidal thickness changes during childhood. The main objective of our study was to characterize the distribution of choroidal thickness profile in healthy Iranian children and adults at different age groups from 4 to 60 years old.1 The different kinds of refractive errors were labeled for each age group. The purpose of the study necessitated performing the examinations on a large sample of subjects from childhood to adulthood with different types of refractive errors. One limitation of our study was that we could not easily find a large number of children up to 10‐year‐old with different types of refractive errors to include in the study. However, considering the poor cooperation of children in the prolonged process of examinations and compared with previous studies, the number of pediatric subjects in the present study seems to be reasonable...
Introduction: This article aimed to review the literatures on visual impairments and ocular chang... more Introduction: This article aimed to review the literatures on visual impairments and ocular changes in premature infants with low birth weight and gestational age.Methods: Five electronic databases including: PubMed, Web of Science, Science direct, Ovid, and Scopus were searched. Original articles published until 2015 describing preterm infants were reviewed. Repetitive and derivative articles were excluded.Results: Out of 100 unique, potentially relevant articles, 42 studies that addressed and met the inclusion criteria were evaluated.Conclusion: Prematurity affects ocular structures (from anterior to posterior segment) and functions. Premature infants are at risk of myopization. Concerning the changes in premature infants, a significant increase is found in axial length, intraocular pressure, and central corneal thickness; moreover, high incidence of retinal changes is reported as a result of prematurity. On the other hand, visual acuity, tear, electroretinogram, and visual evoked...
Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the... more Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods Articles included in the study were taken from PubMed, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals on fasting and vision system. Results Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thicknesses, and also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion Much research related to the effect of dehydration on ocular parameters during Ramadan fasting exists. The findings reveal association with significant changes on ocular parameters. Thus, it seems requisite to have a comprehensive study on "fasting and ocular parameters”, which will be helpful in making decisions and giving plan ...
ABSTRACT Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland... more ABSTRACT Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland dysfunction (MGD) and evaluate its risk factors by gender, age, and ethnicity. Methods: Articles were searched reporting the prevalence of MGD from PubMed, Scopus, Web of Science, and Embase databases. Results: The estimated pooled prevalence of MGD was 0.358 (95% CI 0.26–0.46; I 2: 99.57%). The prevalence of MGD was 0.358 (95% CI 0.24–0.50) in clinical and 0.359 (95% CI 0.22–0.52) in population-based studies. Men were more prone to MGD than women (OR: 1.24, 95% CI 1.01–1.52, p = 0.034). The rate of MGD was between 21.2% and 29.5% in Africans and Caucasians, to 71.0% in Arabs, and 67.5% in Hispanics. Conclusion: MGD is a quite prevalent disorder with an estimated pooled prevalence of 35.8%. Men are more prone to MGD than women. There is a large variation between studies in terms of quality, sample size, age ranges, diagnostic criteria, and ethnicity.
Uploads
Papers by javad heravian shandiz