Prevalence of strabismic binocular anomalies, amblyopia and anisometropia. Rehabilitation Faculty of Shahid Beheshti Medical University (original) (raw)
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The Prevalence of Anisometropia, Amblyopia and Strabismus in Schoolchildren of Shiraz, Iran
Strabismus, 2010
Purpose: To determine the prevalence of amblyopia and strabismus in the schoolchildren of the city of Bojnourd, Iran Methods: In 2010, randomized stratified cluster sampling was employed in a cross-sectional study on primary and junior high schoolchildren. All the examinations were performed in schools. All students received refraction, vision and subjective refraction tests. The cover test was used to determine tropia. Amblyopia was defined as best corrected visual acuity (BCVA) 20 / 30 or less or a 2-line interocular optotype acuity difference with no pathology. Results: Of 2,020 selected students, 1,551 participated in the study (response rate: 76.7%). The prevalence of amblyopia was 2.3% (95% CI: 1.6-3.1); 2% of the male students and 2.5% of the female students had amblyopia (P=0.508). Amblyopia decreased significantly with age (P=0.032). The most common type of amblyopia was anisometropic followed by isometropic amblyopia. Hyperopia and astigmatism were the most common refractive errors in individuals with amblyopia. The prevalence of strabismus in the students was 2% (95% CI: 1.3-2.7). Of female and male students, 2.4% and 1.4% had strabismus, respectively (P=0.160). Of the students with strabismus, 67.7%, 25.8% and 6% had exotropia, esotropia and vertical deviations, respectively. Conclusion: The prevalence of amblyopia and strabismus in the current study was intermediate. However, correction of refractive errors at young ages can largely prevent amblyopia and strabismus in children.
Incidence of Amblyopia in Strabismic population
Pak J Ophthalmol, 2007
To find the incidence and density of amblyopia with reference to the type of squint among the strabismic patients visiting eye department. Material and Methods: This prospective study was started in January 2000 and a total of 177 patients have been dealt with. Both male and female patients of all age groups and all types of squints were included. All the patients underwent standard procedure of assessment including history, examination and investigations to find the type of deviation, amount of the deviation, the presence of amblyopia and the depth of amblyopia. It was then followed by analysis to see the effect of different factors on the depth of amblyopia Results: Out of 177 patients 94 had uniocular squint (Group-I) and 83 alternating squint (Group-II). Majority of patients in Group-I had some degree of amblyopia (82%). Amblyopia was much less in group-II (18%). All the 106 patients having amblyopia showed at least two lines difference of Snellen's Acuity between both eyes. Amblyopia is relatively denser in uniocular than alternating strabismus. It is more common and dense in esotropia than exotropia.
Observations on the relationship between anisometropia, amblyopia and strabismus
Vision Research
We investigated the potential causal relationships between anisometropia, amblyopia and strabismus, specifically to determine whether either amblyopia or strabismus interfered with emmetropization. We analyzed data from non-human primates that were relevant to the coexistence of anisometropia, amblyopia and strabismus in children. We relied on interocular comparisons of spatial vision and refractive development in animals reared with 1) monocular form deprivation; 2) anisometropia optically imposed by either contact lenses or spectacle lenses; 3) organic amblyopia produced by laser ablation of the fovea; and 4) strabismus that was either optically imposed with prisms or produced by either surgical or pharmacological manipulation of the extraocular muscles. Hyperopic anisometropia imposed early in life produced amblyopia in a dose-dependent manner. However, when potential methodological confounds were taken into account, there was no support for the hypothesis that the presence of amblyopia interferes with emmetropization or promotes hyperopia or that the degree of image degradation determines the direction of eye growth. To the contrary, there was strong evidence that amblyopic eyes were able to detect the presence of a refractive error and alter ocular growth to eliminate the ametropia. On the other hand, early onset strabismus, both optically and surgically imposed, disrupted the emmetropization process producing anisometropia. In surgical strabismus, the deviating eyes were typically more hyperopic than their fellow fixating eyes. The results show that early hyperopic anisometropia is a significant risk factor for amblyopia. Early esotropia can trigger the onset of both anisometropia and amblyopia. However, amblyopia, in isolation, does not pose a significant risk for the development of hyperopia or anisometropia.
THE PROFESSIONAL MEDICAL JOURNAL, 2017
To compare the status of stereopsis in anisometropic amblyopic patients of 11-30 years of age and the type of anisometropic amblyopia associated with deficient BSV in patients of Eye OPD of Shalamar Hospital, Lahore. Study design: Descriptive cross sectional study Setting: Eye OPD, Shalamar Hospital, Lahore. Duration: From August 2015 to August 2016. Materials and Methods: Two hundred (200) patients were selected for the study. Computor software SPSS version 16 was used to analyze the data. Categorical data was presented as frequencies and percentages and numerical data presented as mean ± standard deviation. Results: Frequency of anisometropic amblyopia is relatively higher in age groups 26-30. Age group 11-15, 16-20 and 21-25 have relatively low rate of amblyopia due to anisometropia. P = 0.000 a significant value. Conclusion: Frequency and severity of anisometropia in this clinical sample from the Eye OPD of Shalamar Hospital, Lahore that increased as the level of ametropia increased. Both spherical ametropia and astigmatism were independently associated with anisometropia. Furthermore, both Spherical and cylindrical anisometropic amblyopia are independently associated with deficient BSV. Simple hypermetropic amblyopia was the most common cause associate with deficient BSV. The commonly affected age group in our study was 25-30 year.
A study of prevalence of Anisometropia and associated amblyopia in patients with refractive error
International Journal of Medical Research and Review, 2015
Aims: The present study was planned to evaluate the prevalence of anisometropia in patients with refractive error, to compare the prevalence of different types of anisometropia and to study the prevalence of amblyopia in anisometropic patients. Material and Method: It was a cross sectional study in which 400 randomly selected patients were evaluated for anisometropia and also for anisometropic amblyopia. All patients underwent thorough ophthalmic examination including visual acuity testing, slit lamp examination and fundus examination. Later on the data was analysed statistically with different formulas like Chi square test, Fisher exact test etc. Results: The prevalence of anisometropia was found to be 16.5% in total 400 patients with refractive errors, out of which 57.5% were females and 42.5% were male patients. Prevalence was found maximum in 20-30 years age group (36.4%). Highest prevalence among various types of anisometropia was found of compound myopic anisometropia (37.9%). Conclusion: No gender difference was seen in prevalence of anisometropia. Prevalence of anisometropia significantly varied with different age groups. The prevalence of amblyopia in patients of anisometropia was found to be statistically significant (p value=.0001).
Factors Influencing the Prevalence of Amblyopia in Children with Anisometropia
2012
Purpose: To evaluate factors that can influence the prevalence of amblyopia in children with anisometropia. Methods: We retrospectively reviewed the records of 63 children 2 to 13 years of age who had anisometropic amblyopia with a difference in the refractive errors between the eyes of at least two diopters (D). The type of anisometropia (myopia, hyperopia, and astigmatism), degree of anisometropia (＜2-3 D, ＜3-4 D, or ＞4 D), best corrected visual acuity (BCVA) of the amblyopic eye at the time of initial examination, BCVA differences between sound and amblyopic eyes, whether or not occlusion therapy was performed, compliance with occlusion therapy, and the patient's age when eyeglasses were first worn were investigated. Results: There was an increase in the risk of amblyopia with increased magnitude of anisometropia (p=0.021). The prevalence of amblyopia was higher in the BCVA ＜20/40 group and in patients with BCVA differences ＞4 lines between sound and amblyopic eyes (p=0.008 and p=0.045, respectively). There was no statistical relationship between the prevalence of amblyopia and the type of anisometropia or the age when eyeglasses were first worn. Poor compliance with occlusion therapy was less likely to achieve successful outcome (p=0.015). Conclusions: Eyes with poor initial visual acuities of ＜20/40, a high magnitude of anisometropia, and a ＞4 line difference in the BCVA between sound and amblyopic eyes at the initial visit may require active treatment.
Factors Influencing the Success of Treatment in Anisometropic Amblyopia
Purpose: To examine factors influencing successful resolution of mblyopia in children with hyperopic and astigmatic anisometropia presenting to a pediatric ophthalmology practice in London, Ontario. Methods: A retrospective chart review was conducted to identify children treated for hyperopic and astigmatic anisometropia from 2008-2016. 39 children ages 12 years and under with hyperopic and astigmatic anisometropia were included. Information regarding referral pattern, presenting findings and outcomes was collected. Presenting degree of anisometropia, compliance, age at presentation and initial visual acuity (VA) were all statistically analyzed to determine effect on final VA. Results: The mean age at referral to pediatric ophthalmology was 5.2 years. 47% presented with dense amblyopia, with the poorer eye having a VA of 6/30 or worse. 51% of children were successfully treated, with a final VA of 6/9 or better in the worse eye, and 5% of children had residual dense amblyopia. Presenting magnitude of anisometropia was the only factor found to have a significant effect on successful treatment, as for every one diopter decrease in magnitude of anisometropia, there was a 40% higher odds of achieving a final VA of 6/9 or better (point estimate 0.62, 95% CI 0.39-0.97, p=0.03). Age at presentation, presenting VA and compliance to treatment all had no significant outcome on treatment success. Conclusions: Magnitude of anisometropia was found to be the only significant factor that influences the final visual acuity of children, confirming the necessity for early detection of amblyogenic refractive errors.
Risk factors for treatment failure of anisometropic amblyopia
Journal of Analytical and Applied Pyrolysis, 2004
Purpose: This study sought to explore factors which might predict the lack of vision improvement following therapy of anisometropic amblyopia. Methods: We retrospectively reviewed the records of 104 children aged 3 to 8 years who had anisometropic amblyopia with a difference in the refractive power between the two eyes of at least 1 diopter, a difference in corrected visual acuity between the two eyes of at least 3 logMAR units, visual acuity in the amblyopic eye of 20/50 or worse, and no ocular structural abnormalities. Patients were treated with either patching or atropine penalization therapy. Patients with strabismus were included. Treatment failure was defined in two ways: (1) functional failure indicating a final visual acuity in the amblyopic eye worse than 20/40 and (2) relative failure indicating less than three lines of logMAR visual acuity improvement regardless of final vision. Results: Failure risk factors were as follows: age above 6 at the onset of treatment (adjusted odds ratio [OR] (95% confidence limits [CL] = 4.69 [1.55, 14.2]), the presence astigmatism of more than 1.50 diopters in the amblyopic eye (adjusted [OR] (95% CL) = 5.78 [1.27, 26.5]), poor compliance with treatment (adjusted [OR] (95% CL) = 5.47 [1.70, 17.6]), and initial visual acuity in the amblyopic eye of 20/200 or worse (adjusted [OR] (95% CL) = 3.79 [1.28, 11.2]). Strabismus was not found to be a significant risk factor. Neither the type or amount of refractive error nor the difference in the refractive power between the two eyes was a significant risk factor for treatment failure. Conclusion: Eyes with poor initial visual acuity, the presence of significant astigmatism, and age over 6 years were less likely to achieve successful outcome. The clinical profile of patients with anisometropic amblyopia may be useful in predicting response to therapy, but compliance with treatment has a major effect on response to therapy.
2017
Purpose: To determine the prevalence of anisometropia, amblyopia, and strabismus among first year optometry students in Kwame Nkrumah University of Science and Technology (KNUST). Methods: This was a descriptive cross sectional study. The study population included all first year optometry students in KNUST during the 2016/2017 academic year. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. Anisometropia was defined as spherical equivalent (SE) refraction difference of 1.00D or more between the two eyes. Amblyopia was distinguished as a reduction of BCVA to 6/9 or less in one eye or 2-line interocular optotype acuity differences in the absence of pathological causes. Cover tests were done to investigate strabismus. All data was entered into and analyzed using the Statistical Package for Social Sciences version 23, USA. Descriptive analysis and Chisquared test were employed. Statistical significance was set at p<0.05. Resu...
The burden of pure anisometropic amblyopia: a cross-sectional study on 2800 Iranians
International Ophthalmology, 2017
Purpose To assess the proportion of pure anisometropic amblyopia in a sample Iranian (white) population. Methods A total of 2800 consecutive individuals who presented at a referral eye clinic for any reason were examined for the presence of pure anisometropic amblyopia. Anisometropia was reported when a spherical equivalent refraction difference of at least 1.0 D with or without a cylinder refraction difference of at least 1.0 D was present between the two eyes. Amblyopia was defined as the best-corrected visual acuity of 20/30 or worse or a two-line interocular visual acuity difference between eyes that could not be attributed to any structural ocular pathology or visual pathway abnormality. Results Subjects were 1528 females and 1272 males with a mean age of 30.25 ± 14.93 years (range, 5-65). Amblyopia was diagnosed in 192 cases (6.9%), significantly more frequent among females (7.9 vs. 5.7%, p = 0.02). Pure anisometropic amblyopia was present in 6.1% of the study population, significantly more common in patients with spherical hyperopic anisometropia (37.7%) compared to patients with spherical myopic anisometropia (21.3%), cylindrical myopic anisometropia (4.1%), and cylindrical hyperopic anisometropia (15%) (p \ 0.001). Conclusions Pure anisometropic amblyopia is a common finding in Caucasians seeking eye care, particularly when anisometropia is of spherical hyperopic subtype.