P100 wave latency in anisometropic and esotropic amblyopia versus normal eyes

Purpose: To evaluate cortical activity using pattern visual evoked potentials (PVEPs) in patients with mild and moderate amblyopia (esotropic and anisometropic). Methods: PVEP was recorded in 43 unilateral amblyopic patients, including 15 esotropic (ET) and 28 anisometropic (AM) patients, selected from three different medical centers in the city of Shiraz, Iran and compared to that obtained from 15 age and sex matched normal subjects who served as controls. Visual acuity (VA) in amblyopic eyes was equal to or less than 0.7 LogMAR. The latency of P100 was recorded monocularly using two check sizes of 15 and 60 min of arcs at two different levels of contrasts (30 and 100). Results: P100 latency in amblyopic eyes was significantly increased compared to the normal group (P < 0.001). There was a significant difference (P < 0.001) in P100 latency in anisometropic and esotropic amblyopic eyes as compared to normal subjects, using high spatial frequency and with both levels of contrast. A significant difference was observed with large check sizes and high contrast between anisometropic amblyopic and normal eyes (P = 0.03). However, there was no significant difference between these two groups and the control group with other stimuli. Conclusion: The neural response based on p100 latency in PVEP was different between amblyopic groups and normal subjects. PVEP may be valuable for diagnosis, prognosis and treatment of amblyopia. © 2015 Journal of Ophthalmic and Vision Research | Published by Wolters Kluwer - Medknow

Botulinum toxin injection for treatment of acute traumatic superior oblique muscle palsy

Purpose: To evaluate the outcomes of botulinum toxin injection into the inferior oblique (IO) muscle for management of unilateral acute traumatic superior oblique (SO) palsy. Methods: In this prospective case series, 10-20 units of botulinum toxin A (Dysport, Ipsen, Biopharm Ltd., Wrexham, UK) was injected into the ipsilateral IO muscle of 13 consecutive patients with unilateral acute traumatic SO palsy. All patients received injections within four weeks of the incident. Results: Mean age was 29 ± 15 years and 12 (92%) subjects were male. Mean amount of hypertropia (in primary position) was decreased from 10.0 ± 3.9Δ at baseline to 4.6 ± 8.9Δ, one month after the injection, and to 1.5 ± 2.7Δ at final follow-up (P = 0.001). IO overaction improved from 2.7 ± 0.6 to 1.0 ± 1.2 and 0.6 ± 0.9 (P ≤ 0.001), and subjective torsion from 5.3 ± 3.9 to 3.2 ± 3.4 and 1.6 ± 2.5 degrees (P ≤ 0.001), at the same time intervals respectively. One month after the injection as well as at final follow-up, 10 (77%) patients were diplopia-free in primary and reading positions. Subgroup analysis showed that patients who recovered had less baseline hypertropia as compared to those who failed (8.3Δ vs. 15.7Δ, respectively; P = 0.01). All patients with a favorable outcome had baseline hypertropia of 10Δ or less. Conclusion: A single injection of BTA into the IO muscle can rapidly and safely resolve symptomatic diplopia in patients with acute traumatic SO palsy, while waiting for spontaneous recovery

Assessment of TNO stereo test in Amblyopia screening

Background: Many studies have been performed on validity of different methods for Amblyopia screening and this one was designed to assess the reliability of the TNO test for that purpose. Materials and Methods: This is a diagnostic value study. Visual acuity and stereo acuity of 100 patients with Amblyopia caused by refractive errors, strabismus with wide angle, or micro strabismus were measured and compared with the stereo acuity of 300 normal students using TNO test. Statistical analysis carried out to determine sensitivity, specificity, and diagnostic value. Then, positive and negative predictive values were calculated by considering 120 seconds of arc stereopsis as the cut off point. Results: Ninety five percent of students had good stereopsis (120 second of arc or better). Patients group showed limited stereopsis. The most common cause of amblyopia in patients group was refractive errors (62). The most defective stereopsis was clearly associated with wide angle strabismus. In this study TNO test had missed (underestimated) 8 of cases with Amblyopia and had 5 over referral rate but had sufficient power to detect patients with moderate to severe Amblyopia. Its sensitivity and specificity were 85.9 and 97.2 respectively. Conclusion: TNO test seems to be useful for screening purposes of Amblyopia. It is reliable and can be performed without having special skills. Lack of monocular clues, also, increases its value

The effects of microwave radiation on rabbit's retina

Purpose: Mobile cell phones are used extensively these days, and their microwave (MW) radiation has been shown to affect the eye. The purpose of the present study was to evaluate the effects of MW radiation on rabbit retina. Methods: This experimental study (concluded in 2015) was conducted on 40 adult white New Zealand rabbits. A Global System for Mobile Communications (GSM) cell phone simulator was used for MW irradiation. The rabbits were randomized into five groups (8 in each) and treated as follows: Group 1: no irradiation (sham); Group 2: irradiation at 10 cm for 1 day; Group 3: irradiation at 30 cm for 1 day; Group 4: irradiation at 10 cm for 3 days; and Group 5: irradiation at 30 cm for 3 days. Scotopic and photopic electroretinography (ERG) responses were obtained at baseline and 7 days after the last exposure. Then all the rabbits were euthanized, and their eyes were enucleated and sent for pathology examination. Kruskal–Wallis and Chi-Square tests were used to evaluate intergroup differences in ERG parameters and histological findings, respectively. Results: ERG responses obtained 7 days after irradiation did not show any statistically significant difference between the groups (P > 0.1, for all tested parameters). There were statistically non-significant trends toward greater changes in the MW irradiated eyes. In pathological examination, retina was normal with no sign of degeneration or infiltration. Ciliary body congestion was observed in greater fraction of those who received higher MW doses. (P = 0.005). Conclusions: Histopathologically, cell phone simulated MW irradiation had no significant detrimental effect on the retina. However, ciliary body congestion was observed in greater fraction of those who received higher MW doses. Although there was no significant difference between post-treatment mean ERG values, there were statistically non-significant trends toward greater changes in the MW irradiated eyes

The Shiraz pediatric eye study; A population based survey of school age children: Rationale, design and baseline characteristics

© 2018 Medknow Publications.All Rights Reserved. Purpose: To describe the rationale, study design, methodology, and baseline characteristics of the Shiraz Pediatric Eye Study, a population-based survey of schoolchildren in Shiraz, Iran. Methods: This population-based study included schoolchildren aged 6-12 years from all four educational districts of Shiraz who were recruited in years 2015-2016. Stratified random sampling was used to select 2400 participants from all districts. Data were recorded from a detailed interview and ocular evaluation of each eligible student. The eye examination comprised uncorrected and best corrected visual acuity measurement, refraction, external eye examination (including specific strabismus and lid evaluation tests), slit lamp biomicroscopy, intraocular pressure measurement, the Ishihara color vision test, and stereoacuity. Exophthalmometry, optical biometry, and optical coherence tomography were performed for a randomly selected subset of children. General characteristics and socioeconomic variables were also recorded to assess risk factors. Results: From a total of 2400 selected students, 2001 (83.3%) participated in the study. The mean age of the students was 9.1 ± 1.6 years, and 59.7% were girls. Most children had at least one parent with a diploma or less than diploma (63.5%), and 2.2% had illiterate parents. Conclusion: This study is expected to provide accurate estimates of the prevalence of visual impairments and their related determinants in Shiraz. In addition, it will identify children who should be targeted by blindness prevention programs