Comparison of the wave amplitude of visually evoked potential in amblyopic eyes between patients with esotropia and anisometropia and a normal group

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

[CAM visual stimulation with conventional method of occlusion treatment in amblyopia: a randomized clinical trial]

The application of CAM visual stimulation returns to the date of more than fifty years ago. However, the reports of previous studies in this field vary from no effect to significant effects of this method in amblyopia treatment. The purpose of this study was to determine the effect of CAM visual stimulation along with conventional occlusion therapy in anisometropic amblyopic children. Forty amblyopic children aged 4 to 6 years old with no previous treatment were enrolled in this randomized clinical trial study. The subjects were randomly assigned in two different groups. The group 1 included conventional occlusion therapy and group 2 includes occlusion therapy with complementary CAM visual stimulation. In terms of visual acuity and stereopsis improvement and reduction of amblyopia severity, two groups were compared using the repeated measure ANOVA and LSD Post Hoc tests. In group 1 including conventional occlusion therapy, visual acuity improved from 0.444 +/- 0.077 logMAR to 0.138 +/- 0.023 logMAR, i.e., improvement of 0.306 logMAR [P<0.001] whereas in group 2 including complementary CAM usage, visual acuity improved from 0.398 +/- 0.075 logMAR to 0.047 +/- 0.022 logMAR, i.e., improvement of 0.351 logMAR [P<0.001]. Regarding Stereopsis, the improvements were 157 [from 258 +/- 34 to 101 +/- 13 seconds of arc, P<0.001] and 171 [from 237 +/- 33 to 66 +/- 12 seconds of arc, P<0.001] for groups 1 and 2 respectively. All subjects of group 2 gained the normal vision at the end of the treatment period, whereas only 47% of subjects of group 1 could achieve this level of vision in that time. Improvement of visual acuity in group 2 was significantly better than group 1 [P<0.05]. Using of CAM visual stimulation along with conventional occlusion will further improve visual acuity and stereopsis in amblyopic children. These findings recommended the CAM visual stimulation as an accompanying and complementary method in amblyopia treatment

Comparison of blue-yellow opponent color contrast sensitivity function between female badminton players and non-athletes

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

Valuation of ocular accommodation, convergence and fusional vergence changes during Ramadan

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

Frequency domain electroretinography in retinitis pigmentosa versus normal eyes

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