dr. javad heravian

Objective measurement of visual acuity using VEP is high valued in patients with low levels of cooperation. Therefore, this study aimed to investigate the effect of spatial frequency on VEP components in visual acuity using Sweep VEP.

In this cross-sectional study 63 medical students with an age of 22.81 ± 3.93 were selected. After a completed eye examination, refractive error was determined, and best-corrected visual acuity as subjective was recorded by the Freiburg Acuity contrast test. Sweep VEP using the Roland electrophysiology system was recorded for various spatial frequencies from 2 to 37.5 cycles per degree. VEP components were the latencies of N1, P1, N135, and the amplitude of VEP.

Repeated measures of the ANOVA test showed that the effect of spatial frequency on latencies and amplitude of VEP was significant (P<0.001). Paired T-test showed that there was a significant difference between subjective visual acuity and extrapolation of visual acuity with VEP (P<0.001).

According to the significant relationship between VEP amplitude and spatial frequencies of the visual stimuli obtained in this study, the Sweep VEP technique can be used as a valid and objective tool in the determination of visual acuity, especially in patients with low levels of cooperation.

To evaluate the long-term outcomes of collagen crosslinking in early keratoconus.

Thirty eyes of twenty patients with early keratoconus were enrolled. Uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), objective refraction, subjective refraction, corneal topography and pachymetry were assessed before and 3, 6, 12 months and 9 years after performing collagen crosslinking surgery.

The patients’ mean age was 31.2 ± 5.59 years at nine-year follow-up (range, 25–44 years). The means of preoperative UCVA and BSCVA were 0.57 ± 0.34 and 0.15 ± 0.12 logMAR, respectively, and these values remained stable at the final follow-up (P = 0.990 and P = 0.227, respectively). The mean objective spherical equivalent decreased considerably from –6.00 ± 4.05 D preoperatively to –5.22 ± 3.71 D at the final follow-up (P < 0.05). The mean subjective spherical equivalent was –4.25 ± 2.87 D preoperatively and this value was stable at the last follow-up (P = 0.92). No considerable difference was found between the post- and preoperative mean objective cylinder values (P = 0.34). The mean subjective cylinder value changed significantly from –4.05 ± 1.85 D preoperatively to –3.1 ± 1.42 D at the final follow-up (P < 0.05). The mean central corneal thickness was 496.97 ± 45.95 μm preoperatively and this value was stable at nine-year follow-up (P = 0.183). No significant difference was found between the pre- and postoperative mean maximum and mean minimum corneal curvature values (P = 0.429 and P = 0.248, respectively). There were no significant postoperative complications.

Corneal crosslinking in early keratoconus seems to be a safe procedure that can effectively stabilize UCVA, BSCVA, subjective SE and CCT, while improving objective spherical equivalent.

To determine the prevalence of color vision deficiency (CVD) in the northeast of Iran. This cross-sectional, population-based study was conducted in Mashhad, in the northeast of Iran. Multistage cluster sampling was used for selecting the participants. After preliminary screening, the subjects underwent a complete ophthalmic examination. The examination included the measurement of visual acuity, refraction, and slit-lamp biomicroscopy. The Farnsworth D-15 test was used to detect CVD. The color vision test was done with the best optical correction. Of the 4453 invitees, 3132 participated in the study (response rate: 70.4%). The overall prevalence of CVD in this study was 13.93% [95% confidence interval (CI): 12.44e15.41]. The prevalence of CVD in males and females was 15.85% (95% CI: 13.26e18.44) and 12.96% (95% CI: 11.22e14.71), respectively. The most prevalent types of CVD were tritanopia (6.96%; 95% CI: 5.84e8.08), deuteranopia (3.92%; 95% CI: 3.14e4.70) and tritanomalous (2.21%; 95% CI: 1.55e2.86), respectively. According to the results of logistic regression, the odds of having protanopia were higher in females than males [Odds ratio (OR) ¼ 4.80; 95% CI: 1.20e19.18]. The odds of having deuteranopia were lower in females than males (OR ¼ 0.52; 95% CI: 0.35e0.76). The odds of having CVD were lower in 16e30 (OR ¼ 0.52; 95% CI: 0.37e0.73) and higher in 46e60 (OR: 1.41; 95% CI: 1.01e1.97) year age groups compared to 7e15 year age group. The odds of having tritanopia in 16e30 and 46e60 year age groups was 0.56 (95% CI: 0.35e0.90) and 1.79 (95% CI: 1.19e2.67) compared to 7e15 year age groups, respectively. The prevalence of CVD was high in this study, especially in males and people over 46 years of age. Planning for involvement of ocular disease control programs in health care systems can be helpful in the reduction of CVD and improving the quality of life in affected patients.

Hearing impaired children are heavily dependent on their sense of vision to develop efficient communication skills; any contrast sensitivity defect can negatively impact their lives because they are not able to use auditory stimuli to recognize probable dangers in the world around them. The purpose of this study was to determine the contrast sensitivity abnormalities in deaf individuals.
In this cross-sectional study, contrast sensitivity of 15- to 20-year-old high-school boys with hearing disability from Tehran, Iran were evaluated. Sixty-four eyes were tested for contrast sensitivity and refractive error. All subjects had an intelligence quotient (IQ) >70. We investigated their contrast sensitivity with Vector vision CVS-1000 in 4 different spatial frequencies.
Profound hearing loss was noted in 50% of the subjects. The frequency of contrast sensitivity abnormalities in 4 different spatial frequencies varied between 51.6% and 65.6%. The largest abnormalities were recorded at 18 cycles per degree. Only 12.5% of deaf students had corrected distance visual acuity (CDVA) greater than zero (in LogMAR). The abnormalities in contrast sensitivity showed no correlation with the type or severity of hearing loss.
Hearing impaired boys are at a greater risk for contrast sensitivity abnormalities than boys with normal hearing. The larger frequency of contrast sensitivity abnormalities in high spatial frequencies than in other frequencies may demonstrate greater defects in the central visual system compared with the periphery in individuals with hearing loss.

PurposeTo investigate the effects of religious fasting during the month of Ramadan on intraocular pressure (IOP), refractive error, corneal tomography and biomechanics, ocular biometry, and tear film layer properties.
MethodsThis prospective study was carried out one week before and in the last week of Ramadan. Ninety-four eyes of 94 healthy adult volunteers (54 males and 40 females) with a mean ± SD age of 35.12 ± 9.07 were enrolled in this study. Patients with any systemic disorder, ocular disease, or a history of previous surgery were excluded. Corneal tomography and biomechanics, ocular biometry, IOP, refractive error, and tear break up time (TBUT) were evaluated in non-fasting and fasting periods by the Pentacam (Oculus), Corvis ST (Oculus), IOL Master (Carl Zeiss), computerized tonometer (Topcon CT-1/CT-1P), auto kerato-refractometer (Topcon KR-1), and Keratograph 5M (Oculus), respectively.
ResultsThere was no significant difference in the central corneal thickness (CCT) between the study groups (P = 0.123) using the Pentacam while the Corvis ST showed a significant difference in all participants (P ConclusionThis study showed that ACD, IOP, CCT, and peak distance were different between fasting and non-fasting groups while no difference was observed in other ocular parameters. Interpretations of these significant differences should be considered in the clinical setting.

This study aimed to assess the possible relationship of body mass index (BMI) and blood pressure (BP) with corneal biomechanical parameters in healthy subjects. The study included 88 eyes of 88 healthy subjects aged 20–40 years. After a thorough medical history, a digital sphygmomanometer was used to measure the systolic blood pressure (SBP) and diastolic blood pressure (DBP). In addition, several hematological and biochemical parameters were determined to assess general health. Before the ophthalmic examination, the body height and weight were measured; then, the BMI was calculated. Finally, after comprehensive ophthalmic examination, all cases were evaluated with Pentacam (Oculus) in order to rule out corneal ectasia; then, the corneal biomechanical parameters of all individuals were measured using the Scheimpflug-based Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany). If the measurements of the hematological and biochemical parameters were within normal range, the results of the Corvis ST, BMI, and BP were included in the analysis carried out with SPSS software. The mean (± standard deviation [SD]) BMI, SBP, DBP, intraocular pressure (IOP), central corneal thickness (CCT), deformation amplitude, radius, and peak distance was 27.24 ± 4.80 kg/m2, 116.47 ± 11.21 mmHg, 80.51 ± 5.68 mmHg, 15.10 ± 1.70 mmHg, 533.10 ± 30.97 m, 1.03 ± 0.11 mm, 7.51 ± 0.86 mm, and 5.03 ± 0.30 mm, respectively. According to the World Health Organization’s classification of BMI, the results showed no significant difference in IOP, CCT, peak distance, radius, and deformation amplitude between different BMI subcategories (all P > 0.05). The results of the Corvis ST showed that corneal biomechanical parameters had no significant correlation with BMI, SBP, and DBP in three subgroups of BMI and all participants (all P > 0.05) but the results showed a positive correlation between CCT and IOP (P 0.05). This study showed that BMI and BP had no correlation with corneal biomechanical parameters in healthy subjects using the Corvis ST. Our results can be used in clinical practice.

Annually, millions of Muslims all over the world observe the fasting rules based on its measures; this highlights the importance of studies in this field as a worthwhile model for intermittent fasting. It is obvious that changes in lifestyle over fasting have outstanding effects on physiological parameters. The current study was carried out to investigate the IOP and serum electrolytes as two important factors that are influenced by human lifestyle.
Eighty-nine fasting and healthy participants including men and women with mean age of 34.97 were included in our study based on the inclusion and exclusion parameters. During this project, Ramadan coincided with the summer (between June and July 2015). All participants were monitored by an expert examiner and blood samples were collected and IOP was measured by tonometer (Topcon, 1-75, Hasunuma-cho, Itabashi-KU, Tokyo, Japan 2014). The participants were examined one week before and one week after Ramadan.
There was a significant reduction in physiological IOP in healthy people after Ramadan. In line with this, the serum electrolytes were altered by fasting so that Na, K, Se experienced a significant decrease while serum phosphorous increased (P Prolonged intermittent fasting in Ramadan changed IOP and serum electrolytes in healthy people within a normal range.

Fasting during the month of Ramadan is obligatory for healthy Muslims after the age of puberty. This paper was aimed to compare the changes in hematological and biochemical parameters before and after Ramadan.
This prospective study was performed one week before and one week after the month of Ramadan in 2015. Eighty-nine subjects (51males and 38 females) with a mean age of 34.52±9.05 were enrolled in this study. Patients with systemic disorder, special drug using, and/or a history of previous surgery were excluded. Blood samples were taken from all participants before and after Ramadan to evaluate the effects of fasting on hematological-biochemical factors. Hematological and biochemical measurements were performed on the blood samples using a KX-21N cell counter (Kobe, Japan) and Hitachi 717 analyzer (Roche, Japan), respectively.
Hematocrit, red blood cell (RBC) and Mean Red Cell Volume (MCV) decreased after Ramadan fasting (P= 0.002, P= 0.030 and P= 0.005, respectively), however mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) increased (P=0.004, P=0.002, respectively). On the other hand, no changes were seen in hemoglobin, platelets and white blood cell (WBC) after Ramadan (P=0.900, P=0.923, P=0.282, P=0.300, respectively).
In this study, fasting led to decrease in uric acid, creatinine, selenium, sodium and potassium (P=0.00, P=0.015, P=0.021, 0.007 and 0.028, respectively), however, phosphor serum increased after fasting period (P=0.032). Moreover, no changes were seen in other biochemical parameters including fast blood sugar (FBS), urea, calcium, iron, zinc, and albumin (P= 0.54, P=0.300, P=0.054, P=0.372, P=0.170, and P=0.400, respectively).
This study on healthy subjects suggests that fasting could affect some hematological-biochemical parameters but not all of them. Also, these changes in hematological-biochemical parameters were within the normal range and Ramadan fasting seems to be safe for healthy subjects.

This study was intended to investigate the visual field status and its association with other visual parameters in adolescent boys and to compare these outcomes to hearing ones.
In a cross-sectional study, Visual fields (VF) of 64 adolescent boys with hearing impairments and 68 age-matched boys with normal hearing were evaluated among high school students of Tehran, Iran in 2013. They all had intelligence quotient (IQ) more than 70. Status of hearing loss was classified based on the severity and time of onset. Participants underwent a complete eye examination. Their visual fields were investigated to determine Foveal Threshold (FT), Mean Deviation (MD) and status of Glaucoma Hemifield Test (GHT) by using Humphrey Field Analyzer Automated Perimetry.
There was no significant difference in age (P= 0.49) or IQ (P= 0.13) between groups. There was no significant difference in the mean (±SD) of corrected distance visual acuity between two groups (P= 0.183). Most of hearing loss boys (50%) had a deep impairment. Frequency of abnormal VF based on the GHT, MD and FT in hearing loss versus hearing group were 31.2% vs. 8.8%, 59.4% vs. 19.1% and 40.6%vs. 22.1% respectively. The mean±SD of MD and FT in hearing and hearing loss groups were -0.79±2.04 vs. -4.61±6.52 and 38.97±1.66 vs. 35.30±1.43, correspondingly. There were significant differences for MD (P

Background and Age related macular degeneration is the most common cause of sever visual impairment and blindness among adults over the age of 65 years in developed countries. The purpose of this study was to review the literature on using low vision aids in age related macular degeneration and their effects on their quality of life. A comprehensive search of PubMed, Scopus and Ovid databases was conducted to identify suitable articles published until April 2015. The search keywords included: age related macular degeneration combined by optical low vision aids, non-optical low vision aids, quality of life, preferred retinal locus, telescope, and microscope. Finally 76 articles were selected. Previous studies showed that age related macular degeneration can have profound effect on an individual’s quality of life, psychological wellbeing and ability to carry out daily tasks such as driving, face recognition, reading and so on. Although new medical treatments have improved AMD’s prognosis, but vision related disability remains a major problem and the majority of the treated patients do not regain their lost vision. So, optical devices could be used as alternative treatments to help these patients and improve their visual performance. Different low vision aids such as Implantable Miniature Telescopes are designed to help the involved patients. Many studies that were conducted to evaluate the efficacy of these systems indicated the potential benefit of optical devices for patients with age related macular degeneration in improving their quality of life.

To compare the prevalence of refractive errors, amblyopia, and strabismus between hearing-impaired and normal children (7–22 years old) in Mashhad. In this cross-sectional study, cases were selected from hearing-impaired children in Mashhad. The control group consisted of children with no hearing problem. The sampling was done utilizing the cluster sampling method. All of the samples underwent refraction, cover test, and visual examinations. 254 children in the hearing-impaired group (case) and 506 children in the control group were assessed. The mean spherical equivalent was 1.7 ± 1.9 D in the case group, which was significantly different from the control group (0.2 ± 1.5) (P < 0.001). The prevalence of hyperopia was 57.15% and 21.5% in deaf and normal children, respectively, but myopia was mostly seen in the control group (5.5% versus 11.9%, P = 0.007). The mean cylinder was 0.65 ± 1.3 D and 0.43 ± 0.62 D in deaf and normal subjects, respectively (P = 0.002). 12.2% of deaf subjects and 1.2% of normal subjects were amblyopic (P < 0.001), and the prevalence of strabismus was 3.1% in the case group and 2.6% in the control group (P = 0.645). In a comparison of children of the same ages, hearing-impaired children have significantly more eye problems; therefore, a possible relation between deafness and eye problems must exist. Paying attention to eye health assessment in hearing-impaired children may help prevent adding eye problems to hearing difficulties.

Presence of neurophysiological abnormalities in dyslexia has been a conflicting issue. This study was performed to evaluate the role of sensory visual deficits in the pathogenesis of dyslexia. Pattern visual evoked potentials (PVEP) were recorded in 72 children including 36 children with dyslexia and 36 children without dyslexia (controls) who were matched for age, sex and intelligence. Two check sizes of 15 and 60 min of arc were used with temporal frequencies of 1.5 Hz for transient and 6 Hz for steady‑state methods. Mean latency and amplitude values for 15 min arc and 60 min arc check sizes using steady state and transient methods showed no significant difference between the two study groups (P values: 0.139/0.481/0.356/0.062). Furthermore, no significant difference was observed between two methods of PVEPs in dyslexic and normal children using 60 min arc with high contrast (P values: 0.116, 0.402, 0.343 and 0.106). The sensitivity of PVEP has high validity to detect visual deficits in children with dyslexic problem. However, no significant difference was found between dyslexia and normal children using high contrast stimuli.

Ramadan is a holy month for Muslims during which avoid from eating, drinking and sexual intercourse for about 13-17 hours. The aim of this study was surveying the effects of Islamic fasting in Ramadan on lipid profile and blood pressure. we designed this study in two phases, a week before and a week after Ramadan month. Eighty nine healthy subjects with 20-50 years old were participated in this study. Blood sampling for lipid profile measurement was done in the morning and blood pressure was measured in the afternoon with digital sphygmomanometer. Statistical analysis was performed with SPSS version 16.0 software. In a week after Ramadan, body weight and body mass index (BMI) decreased in both sexes, comparing with the week before Ramadan measurements (p

This study was conducted to evaluate the effect of contraction and relaxation of ciliary muscle caused by pilocarpine and tropicamide eye drops on corneal radius, central corneal power and corneal astigmatism. This prospective study was performed on sixty normal and healthy eyes of sixty volunteers with a mean age of 38.19 year (range 18 to 49 years) and without any ocular pathology. Volunteers divided into 2 groups of thirty, in the first group corneal topography of both eye were measured before and 30 minutes after instillation of topical tropicamide 0.5% in only one eye, and the other eye was the control eye and no drop was given. In the second group, the same routine was performed, except that subject received on drop of pilocarpine 1% in one eye. Statistical comparison between groups for the central corneal power, corneal radius and corneal astigmatism were performed using paired t test. In group 1, no significant changes were found in corneal radius, power and astigmatism, however, in group 2 subjects who have received pilocarpine eye drop, mean corneal radius value decreased significantly by 0.05 mm and mean corneal power increased by a plus power of +0.32 D. There was no significant change in corneal astigmatism in both groups. It seems that pilocarpine induced ciliary muscle contraction which may cause pressure on corneal limbus of cornea and scleral spur that resulted in changes in corneal curvature. But tropicamide eye drop did not affect corneal radius and other corneal parameters and corneal topography can be carried out after instillation of tropicamide eye drop.

There is no legal requirement for Iranian military truck drivers to undergo regular visual checkups as compared to commercial truck drivers.. This study aimed to evaluate the impact of drivers’ visual checkups by comparing the visual function of Iranian military and commercial truck drivers..Patients and In this comparative cross-sectional study, two hundred military and 200 commercial truck drivers were recruited and their Visual Acuity (VA), Visual Field (VF), color vision and Contrast Sensitivity (CS) were assessed and compared using the Snellen chart, confrontation screening method, D15 test and Pelli-Robson letter chart, respectively. A questionnaire regarding driving exposure and history of motor-vehicle crashes (MVCs) was also filled by drivers. Results were analyzed using an independent samples t-test, one-way ANOVA (assessing difference in number of MVCs across different age groups), chi-square test and Pearson correlation at statistical significance level of P < 0.05.. Mean age was 41.6 ± 9.2 for the military truck drivers and 43.4 ± 10.9 for commercial truck drivers (P > 0.05). No significant difference between military and commercial drivers was found in terms of driving experience, number of MVCs, binocular VA, frequency of color vision defects and CS scores. In contrast, the last ocular examination was significantly earlier in military drivers than commercial drivers (P < 0.001). In addition, 4% of military drivers did not meet the national standards to drive as opposed to 2% of commercial drivers. There was a significant but weak correlation between binocular VA and age (r = 0.175, P < 0.001). However, CS showed a significantly moderate correlation with age (r = -0.488, P < 0.001).. The absence of legal requirement for regular eye examination in military drivers caused the incompetent drivers to be missed in contrast to commercial drivers. The need for scientific revision of VA standard for Iranian drivers is also discussed. The CS measurement in visual checkups of older drivers deserves to be investigated more thoroughly..

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. Articles included in the study were taken from Pub Med, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals in fasting and eye. 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 thickness. And also a decrease in IOP, tear secretion, and vitreous thickness. Besides many research in relation to effect of dehydration impact on ocular parameters during Ramadan fasting, although the findings reveal it is associated with significant changes on ocular parameters. It seems requisite to have comprehensive study in «fasting and ocular parameters” which will be helpful in making decision and giving plan to the patients.

To evaluate refractive errors in school age children with color vision deficiency (CVD) and those with normal color vision (NCV) in order to make a better understanding of the emmetropization process. A total of 4,400 primary school students aged 7–12 years were screened for color vision using Ishihara pseudoisochromatic color vision plate sets. Of these, 160 (3.6%) students had CVD. A total of 400 age‑ and sex‑matched students with NCV were selected as controls. Refractive status was evaluated using objective cyclorefraction. The CVD group included 136 male (85%) and 24 female (15%) subjects with mean age of 10.1 ± 1.8 years. The NCV group comprised of 336 male (84%) and 64 female (16%) subjects with mean age of 10.5 ± 1.2 years. The prevalence of myopia (7.7% vs. 13.9%, P < 0.001) and hyperopia (41% vs. 57.4%, P = 0.03) was significantly lower in the CVD group. Furthermore, subjects with CVD subjects demonstrated a lower magnitude of refractive errors as compared to the CVD group (mean refractive error: +0.54 ± 0.19 D versus + 0.74 ± 1.12 D, P < 0.001). Although the lower prevalence of myopia in subjects with CVD group supports the role of longitudinal chromatic aberration in the development of refractive errors; the lower prevalence of hyperopia in this group is an opposing finding. Myopia is a multifactorial disorder and longitudinal chromatic aberration is not the only factor influencing the emmetropization process.

To determine the range of contrast sensitivity (CS) and its determinants in a normal population, Mashhad, Iran. In this cross-sectional population based study, 4,453 individuals were invited of whom 3,132 persons agreed to participate (response rate, 70.4 %). CS data from 2,449 eligible individuals were analyzed. CS was determined using the Cambridge low contrast square-wave grating test, and its associations with age, gender, best-corrected visual acuity (BCVA) and manifest refraction spherical equivalent (MRSE) refractive error, were analyzed. Mean age of the participants was 29.1 ± 17.3 (range, 4-89) years and 66.4 % were female. Mean CS was 239.6 ± 233.3 and 234.6 ± 228.6 cps in right and left eyes, respectively. Mean binocular CS was 310.9 ± 249.0 cps. Multiple linear regression showed that CS was inversely correlated with older age (Beta = -1.1, P < 0.001), female gender (Beta = -40.1, P < 0.001), poorer BCVA (Beta = -165.4, P < 0.001), and severity of myopia (Beta = -10.2, P < 0.001). The normal range of Cambridge low-contrast grating test reported herein may serve as a reference for the general population in Iran. Our findings can be used for both research and clinical applications, particularly for evaluations of the outcomes of refractive surgery. In the current study, CS was lower in older subjects, myopic individuals and patients with lower BCVA.

The aim of this study was to determine the prognosis of visual acuity and contrast sensitivity in keratoconus patients according to the correlation between aberrations changes before and after RGP lenses. Methods and Materials: A total of 40 eyes of twenty patients 20 to 40 years with mild، moderate keratoconus were participated in this study. Ocular examinations were included VA with standard Snellen chart، CS with CSV 1000 chart and HOAs with technolas aberrometer objective (Bush & Luamb). All these tests were performed before and after RGP lenses. Refraction and corneal radius of curvature were measured using Autokeratometr. Data were then analyzed with Spss softwair version 11. 5. Mean contrast sensitivity at each spatial frequency with RGP lenses was higher than the best correction in both male and female. Compairing with best correction mean high order aberration of the 5 and 6 mm pupil was reduced with RGP lenses but the effect was not statistically significant different. Mean high order aberration with pupil 6 mm was more than pupil 5 mm. Using Pearson correlation test، there was no significant correlation between visual change and Contrast sensitivity changes with high order aberrations. Visual performances and visual acuity were improved with RGP lens than best correction by reduction of high-order aberrations. However، there was no correlation or relationship between high order aberrations and visual performance. This indicates that Aberrometery condition was unrelated with Prediction of visual acuity changes in this patients.

To evaluate the efficacy of pattern visual evoked potentials (PVEP), standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP), contrast sensitivity (CS), stereoacuity testing in detecting subclinical visual impairment in visually asymptomatic patients with multiple sclerosis (MS) and no history of optic neuritis Twenty-seven eyes of 27 patients (7 males, 20 females, average age 33.81 ± 9.33 years) with confirmed diagnosis of MS, underwent PVEP with 60-minute arc and 15-minute arc check sizes, SAP (Humphrey 750-II, program central 30-2, SITA standard strategy), SWAP (Humphrey 750-II, program central 30-2 full-threshold strategy), CS with CSV1000E chart, Stereoacuity by the Randot stereoacuity (RSA) test. They were age and sex matched with twenty seven healthy volunteers as a control group. Stereoacuity score was significantly reduced in MS group compared with controls (p=0.007). P100 latency time for both 60-minute arc and 15-minute arc was significantly prolonged in MS group compared with controls (p=0.005, p=0.002 respectively). P100 amplitude for both check sizes significantly reduced in MS group compared with controls (p<0.001). When comparing MS patients with the control group significant differences were found for SAP mean deviation (MD), SWAP MD, SAP pattern standard deviation (PSD), SWAP PSD (p<0.001). By considering predefined criteria, asymptomatic MS patients have shown abnormal stereoacuity in 22.2%, abnormal VEP in 40.7%, abnormal CS in 37%, abnormal SAP in 44% and abnormal SWAP in 37% of patients. Our results showed the probable presence of subclinical visual impairment among MS patients without optic neuritis history and no visual symptoms. This emphasizes the importance of the follow-up programs, even in asymptomatic patients with MS. Comparison of multiple tests could help in better understanding of silent visual impairment. However, performing VEP and perimetry test together are useful choices in the regular assessment of these patients.

To determine the prevalence of the uncorrected refractive errors in Bojnourd students In a cross-sectional study, the samples were selected proportionate to the population of the schools using stratified randomized cluster sampling. The target population was the primary and junior high school students of the city of Bojnourd. Visual acuity (VA) (Snellen chart) and cycloplegic, non-cycloplegic and subjective refraction were measured in all students. Uncorrected visual acuity (UCVA) was defined as improvement in corrected vision for at least 2 lines as compared to the presenting vision. Of 2,020 selected students, 1,551 were included in the study (response rate 76.7%). The prevalence of uncorrected refractive errors was 6.2% (95% CI: 5-7.4) in at least one eye and 2.8% of the students had uncorrected refractive errors in both eyes. The prevalence of the uncorrected refractive errors was marginally higher in girls (p=0.068). Age, education level of the father and employment of the mother did not correlate with uncorrected refractive error. Myopic individuals followed by astigmatic students had the highest uncorrected refractive error. The presenting vision did not differ with the corrected vision in 83.3% of the participants. In 2.5% and 0.8% of the study population, vision improved by at least 3 and 4 lines after correcting vision, respectively. In individuals with glasses, the vision improved by at least 2, 3 and 4 lines in 21.1%, 9.5% and 3.2% respectively as compared to their present glasses. The prevalence of the uncorrected refractive errors in students was not low in this study. Girls, myopes, and cases of astigmatism showed high rates of uncorrected refractive errors, and it is important that they receive attention. Correcting these errors can help prevent visual impairment at young ages. Identifying uncorrected refractive errors should be among priorities of the health system, specially for students.

Color blindness is a common disorder. The congenital type of color blindness is sex-linked and the genes are located on the X chromosome. The prevalence of color blindness among males and females are 5-8 % and 0.5 % respectively. Color blindness can affect daily activity as a disability. Therefore, the aim of this study is finding the prevalence of color blindness and its effect on contrast sensitivity and depth perception among school children in Mashhad.

Four thousand four hundred school children (2408 males and 1992 females) were selected randomly and tested by Ishihara for detecting color blindness. At the second step, the students with color blindness were examined at optometry clinic by Ishihara test again. Two hundred students were also selected randomly to classify in a control group, Cambridge and Titmouse tests were taken on the case and control group.

Among 4400 schoolchildren, 3% suffered from color blindness (5.1% in boys and 0.4% in girls). Ishihara test showed 2.2% deuteranopia, 0.8% protanopia and 0.6% suspect. The results indicate that the congenital color blindness has no effect on contrast sensitivity and depth perception.

The present report provides valuable information regarding color vision defectiveness among schoolchildren. Effective detection of this anomaly is expected to prevent from substantial effects on their education and future job. It is strongly recommended to perform color vision test at the beginning of a child’s education.

Variations in sterioacuity can be used in assessment of intermittent exotropia. Intermittent exotropia is divergent squint of eyes that is worsened due to daily visual tasks and its resultant tiredness therefore the amount of deviation increases. The purpose of this study is to determine the effect of daily work and resultant tiredness on near sterioacuity among intermittent exotropic patients.

In this cross sectional study, 600 dormitory students of Mashad University of Medical Sciences, ranging in age 21 to 23 years, examined with alternate cover test to diagnose intermittent exotropic cases. 30 students had intermittent exotropia and along with 15 normal cases constituted case-control group. Sterioacuity was measured twice, in the morning and at night, with Randot-SO 001 test and suppression was checked with Bagoloni striate lens and 4 prism diopter base out test. Data was statistically analyzed with version 13 of SPSS software.

The measured deviation in intermittent exotropic cases showed that there is a significant difference between the deviation in the morning and late at night among 23.33% (7 cases) (P=0.00). It is also observed that sterioacuity decreases significantly at night, (P=0.00) among these cases. Despite the increase in deviation among 53.3% (16 cases) at night, steriacuity was not changed significantly. 23.33% (7 cases) did not show any change in the morning and at night, both in deviation amount and sterioacuity measurement.

In most intermittent exotropic people, there is no significant correlation between intermittent exotropia and near sterioacuity variations after daily work and resultant tiredness (P<0.696).

To evaluate cortical and retinal activity by pattern visual evoked potentials (PVEP) in patients with type II diabetes mellitus. PVEP was recorded in 40 diabetic patients including 20 subjects with non-proliferative diabetic retinopathy (NPDR) and 20 others without any retinopathy on fundus photography, and compared to 40 age- and sex-matched normal non-diabetic controls. P100 wave latency was significantly longer in diabetic patients as compared to normal controls.

To determine the prevalence of refractive errors, strabismus and amblyopia in the schoolboys of Varamin city, Iran In a cross-sectional population-based study in 2010, we used random cluster sampling to select the participants from Varamin high school students. Examinations were conducted at the school site under standard conditions. All students had non-cycloplegic refraction, visual acuity (VA) test and cover test. Of the 1,430 selected, 79.2% participated in the study: their mean age was 16.3±1.3 years (range, 14 to 18). The prevalence of myopia [spherical equivalent (SE)≤-0.5 diopter (D)], hyperopia (SE≥+0.5 D) and hyperopia (SE≥+1.0 D) were 33.2% (95% confidence interval (CI): 25.0 to 41.4), 17.5% (95% CI: 8.6 to 26.4) and 6.1% (95% CI: 2.6 to 9.6), respectively. Astigmatism (cyclinder power ≥0.75 D) and anisometropia (difference in SE ≥1.0 D) were detected in 10.5% (95% CI: 8.4 to 12.6) and 3.8% (95% CI: 1.8 to 5.8) of the students. The prevalence of strabismus was 1.5% (95% CI: 0.9 to 2.1) and exotropia was the most prevalent type of strabismus (0.9%). The prevalence of amblyopia was 2.1% and anisometropia was the most common cause (54.2%). There was an unmet need for refractive correction in 15.4% (95% CI: 13.3 to 17.4) of the students. The most common refractive error in the students in this study was myopia, however, the prevalence rate of hyperopia was relatively higher than that in other studies. The unmet need for refractive correction was higher as well. In comparison to other populations, the prevalence of strabismus was low while the prevalence of amblyopia was similar.