ABSTRACT
Background: We compared the wave amplitude of visually evoked potential [VEP] between patients with esotropic and anisometropic amblyopic eyes and a normal group
Methods: The wave amplitude of VEP was documented in 2 groups of persons with amblyopia [15 with esotropia and 28 with anisometropia] and 1 group of individuals with normal visual acuity [n, 15]. The amplitude of P100 was recorded monocularly with different spatial frequencies
Results: Our statistical analysis revealed that the wave amplitude in the 2 groups with amblyopia was significantly decreased compared to that in the normal group [P<0.001]. There was a significant difference regarding the amplitude in high spatial frequencies in both high- and low-contrast conditions between the groups with esotropia and anisometropia and the normal group [P<0.001]. There were also significant differences in large check-size stimuli and low-contrast condition between the amblyopic groups with esotropia and anisometropia and the normal group [P=0.013 and P=0.044, respectively]. In large check-size stimuli and high-contrast condition, a significant difference was indicated only in the comparison between the esotropic amblyopic eyes and the normal eyes [P=0.036]
Conclusion: The wave amplitude parameter of VEP was influenced by both types of amblyopia, but it seems that this parameter was more sensitive to esotropic amblyopia than anisometropic amblyopia. This outcome may reflect a non-parallel pattern of cortical responses in the comparison of the 2 types of amblyopia with each other and with the control group, which may be beneficial for the diagnosis and treatment of amblyopia
ABSTRACT
To compare the chromatic contrast sensitivity Junction [CSF] for the blue-yellow opponent channel [BYOC] between female badminton players and non-athlete controls, We recruited 40 young females [18-25 years old] who played badminton for at least 5 consecutive years as the test group, and 30 age-matched female control; who had no history of regular physical activity. The Pattern generator [TM] system was used to test the CSF for the BYOC which was performed at three spatial frequencies [SFs] of 2 cycles per degree [cpd], 5 cpd, and 25 cpd. Comparison of BYOC thresholds showed significantly better results in rhe lest group for alt three SFs [P<0.001]. B and pass shift [better CSF in the middle SF] was seen in the test group. The control group had low pass [bettfer CSF in the low SF]. Ocular motility [heterophoria, fusional convergence and divergence at far and near distances, and near point of convergence] was better in the test group, but the inter-group difference was not significant. The BYOC threshold results for badminton players indicated a better visual performance which may be a result of enhanced performance of the parallel processing of the parvocellular and magnocellular systems. This may be inherent and/or acquired in badminton players. In addition, badminton players appear to have developed sensory-motor programmed activities. Testing the CSF for BYOC may be useful for athlete selection in different levels and/or used as a criterion for screening players in the field of badminton
ABSTRACT
Objective: Nowadays, many infertile couples can have child by assistant reproductive technology [ART]. Always the undesirable effects of these methods on newborn are considered and are evaluated. The aim of this study is to describe the impact of ART on ocular and visual performances of infants born by these methods
Materials and methods: In a cross sectional descriptive study, 479 infants aged three-nine months presented to an optometry clinic of Child Health and Development Research Department [CHDRD], Tehran, Iran. Static retinoscopy, qualitative fixation evaluation, Hirschberg test, red reflex assessment and external eye examination were carried out. Other information such as birth weight and maturity of the infants was recorded
Results: It was possible to assess only 320 out of 479 infants due to general condition of some participants. Comparison of mean refractive error in infants' right and left eyes did not show any significant difference. Our findings confirmed that 20.3% had poor fixation, while 2,9% revealed manifest strabismus. The results also revealed the prevalences of myopia, hyperopia and emmetropia are 2.9%, 87%, and 10.1%, respectively. Red reflex abnormalities were significantly found in boys and in preterm infants [p<0.05]. Failure of fixation control was seen more frequently with increasing refractive error, which significantly developed in preterm infants [p<0.001]
Conclusion: These results reflect the necessity of more comprehensive assessments and further follow-up of infants born by ART, especially for premature male ART infants. These results also suggest the probability of fixation condition and visual deficiencies in these infants. It is recommended to pay close attention to this preliminary report about the refractive and fixation condition of the infants born after ART
ABSTRACT
There are a few researches regarding the effects of Islamic fasting on visual system. The aim of this study was to investigate the effects of Ramadan fasting on the amplitude of accommodation [AA], near point of convergence [NPC], positive and negative fusional vergences [PFV and NFV, respectively] in visually healthy fasters. AA, NPC, PFV and NFV at far [6m] and near [40cm] were measured in 30 male students. Nutritional habits in a week before each examination visit were assessed with the Food Frequency Questionnaire [FFQ]. Mean age and fasting average experience were 23.9 and 10 years, respectively. AA and NPC showed significant changes [p<0.05] during Ramadan; but there was no significant difference before and after Ramadan in these parameters. NFV blur, break and recovery points at far significantly reduced in Ramadan than before [p=0.003, p=0.005, p=0.003, respectively] with insignificant compensation after Ramadan. Results showed that there was no significant correlation between changes in diet pattern and AA, NPC and distant NFV variations [p<0.05]. Some visual problems may be reported at far and near visual tasks during Ramadan; but most of the problems may be resolved after it. Some visual preparations may be needed for more effective visual activities during Ramadan; essentially for students with intensive visual tasks. Vision therapy may be suggested along with nutrient pattern improvement during Ramadan
ABSTRACT
Purpose: To compare electroretinogram [ERG] characteristics in patients with retinitis pigmentosa [RP] and normal subjects using frequency domain analysis
Methods: Five basic ERG recordings were performed in normal subjects and patients with a clinical diagnosis of RP according to the ISCEV [International Society of Clinical Electrophysiology of Vision] protocol. Frequency domain analysis was performed by MATLAB software. Different frequency domain parameters were compared between the study groups
Results: Peak frequency [Fmod] of flicker and oscillatory responses in RP patients showed significant [P<0.0001] high pass response as compared to normal controls. Peak frequency [Fmod] of the other responses was not significantly different between the two groups
Conclusion: In addition to conventional ERG using time domain methods, frequency domain analysis may be useful for diagnosis of RP. Oscillatory and flicker responses may be analyzed in frequency domain. Fast Fourier transform may reveal two distinct high pass responses [shift to higher frequencies] in Fmod. Time and frequency domain analyses may be performed simultaneously with many modern ERG machines and may therefore be recommended in RP patients