Search results for: strabismic amblyopia

Authors: Husain Rajib, T. H. Sheikh, D. G. Jewel

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Background: Amblyopia is a frequent cause of monocular blindness in children. It can be unilateral or bilateral reduction of best corrected visual acuity associated with decrement in visual processing, accomodation, motility, spatial perception or spatial projection. Anisometropia is an important risk factor for amblyopia that develops when unequal refractive error causes the image to be blurred in the critical developmental period and central inhibition of the visual signal originating from the affected eye associated with significant visual problems including anisokonia, strabismus, and reduced stereopsis. Methods: It is a prospective hospital based study of newly diagnosed of amblyopia seen at the pediatric clinic of Chittagong Eye Infirmary & Training Complex. There were 50 anisometropic amblyopia subjects were examined & questionnaire was piloted. Included were all patients diagnosed with refractive amblyopia between 3 to 13 years, without previous amblyopia treatment, and whose parents were interested to participate in the study. Patients diagnosed with strabismic amblyopia were excluded. Patients were first corrected with the best correction for a month. When the VA in the amblyopic eye did not improve over month, then occlusion treatment was started. Occlusion was done daily for 6-8 hours (full time) together with vision therapy. The occlusion was carried out for 3 months. Results: In this study about 8% subjects had anisometropia from myopia, 18% from hyperopia, 74% from astigmatism. The initial mean visual acuity was 0.74 ± 0.39 Log MAR and after intervention of amblyopia therapy with active vision therapy mean visual acuity was 0.34 ± 0.26 Log MAR. About 94% of subjects were improving at least two lines. The depth of amblyopia associated with type of anisometropic refractive error and magnitude of Anisometropia (p<0.005). By doing this study 10% mild amblyopia, 64% moderate and 26% severe amblyopia were found. Binocular function also decreases with magnitude of Anisometropia. Conclusion: Anisometropic amblyopia is a most important factor in pediatric age group because it can lead to visual impairment. Occlusion therapy with at least one instructed hour of active visual activity practiced out of school hours was effective in anisometropic amblyopes who were diagnosed at the age of 8 years and older, and the patients complied well with the treatment.

Keywords: refractive error, anisometropia, amblyopia, strabismic amblyopia

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Authors: Kristine Kalnica-Dorosenko, Aiga Svede

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Amblyopia or 'lazy eye' is impaired or dim vision without obvious defect or change in the eye. It is often associated with abnormal visual experience, most commonly strabismus, anisometropia or both, and form deprivation. The main task of amblyopia treatment is to ameliorate etiological factors to create a clear retinal image and, to ensure the participation of the amblyopic eye in the visual process. The treatment of amblyopia and eccentric fixation is usually associated with problems in the therapy. Eccentric fixation is present in around 44% of all patients with amblyopia and in 30% of patients with strabismic amblyopia. In Latvia, amblyopia is carefully treated in various clinics, but eccentricity diagnosis is relatively rare. Conflict which has developed relating to the relationship between the visual disorder and the degree of eccentric fixation in amblyopia should to be rethoughted, because it has an important bearing on the cause and treatment of amblyopia, and the role of the eccentric fixation in this case. Visuoscopy is the most frequently used method for determination of eccentric fixation. With traditional visuoscopy, a fixation target is projected onto the patient retina, and the examiner asks to look straight directly at the center of the target. An optometrist then observes the point on the macula used for fixation. This objective test provides clinicians with direct observation of the fixation point of the eye. It requires patients to voluntarily fixate the target and assumes the foveal reflex accurately demarcates the center of the foveal pit. In the end, by having a very simple method to evaluate fixation, it is possible to indirectly evaluate treatment improvement, as eccentric fixation is always associated with reduced visual acuity. So, one may expect that if eccentric fixation in amlyopic eye is found with visuoscopy, then visual acuity should be less than 1.0 (in decimal units). With occlusion or another amblyopia therapy, one would expect both visual acuity and fixation to improve simultaneously, that is fixation would become more central. Consequently, improvement in fixation pattern by treatment is an indirect measurement of improvement of visual acuity. Evaluation of eccentric fixation in the child may be helpful in identifying amblyopia in children prior to measurement of visual acuity. This is very important because the earlier amblyopia is diagnosed – the better the chance of improving visual acuity.

Keywords: amblyopia, eccentric fixation, visual acuity, visuoscopy

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Authors: Rajib Husain, Mezbah Uddin, Mohammad Shamsal Islam, Rabeya Siddiquee

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Purpose: To determine the improvement of visual acuity in patients undergoing occlusion therapy. Methods: This was a prospective hospital-based study of newly diagnosed of amblyopia seen at the pediatric clinic of Chittagong Eye Infirmary & Training Complex. There were 32 refractive amblyopia subjects were examined & questionnaire was piloted. Included were all patients diagnosed with refractive amblyopia between 5 to 8 years, without previous amblyopia treatment, and whose parents were interested to participate in the study. Patients diagnosed with strabismic amblyopia were excluded. Patients were first corrected with the best correction for a month. When the VA in the amblyopic eye did not improve over a month, then occlusion treatment was started. Occlusion was done daily for 6-8 h together with vision therapy. The occlusion was carried out for three months. Results: Out of study 32 children, 31 of them have a good compliance of amblyopic treatment whereas one child has poor compliance. About 6% Children have amblyopia from Myopia, 7% Hyperopia, 32% from myopic astigmatism, 42% from hyperopic astigmatism and 13% have mixed astigmatism. The mean and Standard deviation of present average VA was 0.452±0.275 Log MAR and after an intervention of amblyopia therapy with vision therapy mean and Standard deviation VA was 0.155±0.157 Log MAR. Out of total respondent 21.85% have BCVA in range from (0-.2) log MAR, 37.5% have BCVA in range from (0.22-0.5) log MAR, 35.95% have in range from (0.52-0.8) log MAR, 4.7% have in range from (0.82-1) log MAR and after intervention of occlusion therapy with vision therapy 76.6% have VA in range from (0-.2) log MAR, 21.85% have VA in range from (0.22-0.5) log MAR, 1.5% have in range from (0.52-0.8) log MAR. Conclusion: Amblyopia is a most important factor in pediatric age group because it can lead to visual impairment. Thus, this study concludes that occlusion therapy with vision therapy is probably one of the best treatment methods for amblyopic patients (age 5-8 years), and compliance and age were the most critical factor predicting a successful outcome.

Keywords: amblyopia, occlusion therapy, vision therapy, eccentric fixation, visuoscopy

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Authors: Chinmay V. Deshpande

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Purpose: To assess the efficiency of visual functions and visual skills in strabismic & anisometropic amblyopes and to assess visual acuity and contrast sensitivity in anisometropic amblyopes with spectacles & contact lenses. Method: In a prospective clinical study, 32 children ageing from 5 to 15 years presenting with amblyopia in a pediatric department of Shri Ganapati Netralaya Jalna, India, were assessed for a period of three & half months. Visual acuity was measured with Snellen’s and Bailey-Lovie log MAR charts whereas contrast sensitivity was measured with Pelli-Robson chart with spectacles and contact lenses. Saccadic movements were assessed with SCCO scoring criteria and accommodative facility was checked with ±1.50 DS flippers. Stereopsis was assessed with TNO test. Results: By using Wilcoxon sign rank test p-value < 0.05 (< 0.001), the mean linear visual acuity was 0.29 (≈ 6/21) and mean single optotype visual acuity found to be 0.36 (≈ 6/18). Mean visual acuity of 0.27(≈ 6/21) with spectacles improved to 0.33 (≈ 6/18) with contact lenses in amblyopic eyes. The mean Log MAR visual acuity with spectacles and contact lens were found to be 0.602( ≈6/24) and 0.531(≈ 6/21) respectively. The contrast threshold out of 20 amblyopic eyes shows that mean contrast threshold changed in 9 patients from spectacles 0.27 to contact lens 0.19 respectively. The mean accommodative facility assessed was 5.31(± 2.37). 24 subjects (75%) revealed marked saccadic defects on the test applied. 78% subjects didn’t show even gross stereoscopic ability on TNO test. Conclusion: This study supports the facts about amblyopia and associated deficits in visual skills which are claimed in previous studies. In addition, anisometropic amblyopia can be managed better with contact lenses.

Keywords: strabismus, anisometropia, amblyopia, contrast sensitivity, saccades, stereopsis

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Authors: Anoop T. R., Otman Basir, Robert F. Hess, Ben Thompson

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Strabismus refers to a misalignment of the eyes. Early detection and treatment of strabismus in childhood can prevent the development of permanent vision loss due to abnormal development of visual brain areas. Currently, many children with strabismus remain undiagnosed until school entry because current automated screening methods have limited success in the preschool age range. A method for strabismus detection using eye alignment stability (EAS) is proposed. This method starts with face detection, followed by facial landmark detection, eye region segmentation, eye gaze extraction, and eye alignment stability estimation. Binarization and morphological operations are performed for segmenting the pupil region from the eye. After finding the EAS, its absolute value is used to differentiate the strabismic eye from the non-strabismic eye. If the value of the eye alignment stability is greater than a particular threshold, then the eyes are misaligned, and if its value is less than the threshold, the eyes are aligned. The method was tested on 175 strabismic and non-strabismic images obtained from Kaggle and Google Photos. The strabismic eye is taken as a positive class, and the non-strabismic eye is taken as a negative class. The test produced a true positive rate of 100% and a false positive rate of 7.69%.

Keywords: strabismus, face detection, facial landmarks, eye segmentation, eye gaze, binarization

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Authors: Yahya Maeni

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It is well established that amblyopic patients have a reduced reading performance and oculomotor deficits. Word length has a significant impact on reading performance and eye movement behaviour during reading. As there no previous attempts to assess whether amblyopic eyes would be affected by word length while reading. This study aims to assess the effect of word length on amblyopic eye movement behaviour during reading including fixation duration, number of fixation and gaze duration. 21 adults with amblyopia and 21 age-matched controls participated in the study (age ± SD) (23.80 ± 4.66) for amblyopes and (24.20 ± 3.58) for Controls. Eye movement was recorded during reading binocularly using Eyelink 1000. Study was designed as 2 x 2 (amblyopia vs. control) x 2 lengths (4 letters, and 8 letters). Compared to controls, the amblyopic participants report significant longer duration of fixation, higher number of fixation and longer gaze duration for short words with far higher significant difference for long words. It could be concluded that eye movement in amblyopia during reading might be accounted for by the length of a word within a text and this could possible explanation of reduced reading performance among amblyopes. By understanding the effect of word length on amblyopia will shed light on reading deficits in amblyopia and help to determine the reading needs of amplyopes in educational and clinical settings.

Keywords: amblyopia, eye movement, reading, fixation

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Authors: Hebah M. Musalem, Jeylan El-Mansoury, Lin M. Tuleimat, Selwa Alhazza, Abdul-Aziz A. Al Zoba

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Background: Amblyopia is a condition that affects the visual system triggering a decrease in visual acuity without a known underlying pathology. It is due to abnormal vision development in childhood or infancy. Most importantly, vision loss is preventable or reversible with the right kind of intervention in most of the cases. Strabismus, sensory defects, and anisometropia are all well-known causes of amblyopia. However, ocular misalignment in Strabismus is considered the most common form of amblyopia worldwide. The risk of developing amblyopia increases in premature children, developmentally delayed or children who had brain lesions affecting the visual pathway. The prevalence of amblyopia varies between 2 to 5 % in the world according to the literature. Objective: To determine the different causes of Amblyopia in pediatric patients seen in ophthalmology clinic of a tertiary care center, i.e. King Faisal Specialist Hospital and Research Center (KFSH&RC). Methods: This is a hospital based, random retrospective, based on reviewing patient’s files in the Ophthalmology Department of KFSH&RC in Riyadh city, Kingdom of Saudi Arabia. Inclusion criteria: amblyopic pediatric patients who attended the clinic from 2015 to 2016, who are between 6 months and 18 years old. Exclusion Criteria: patients above 18 years of age and any patient who is uncooperative to obtain an accurate vision or a proper refraction. Detailed ocular and medical history are recorded. The examination protocol includes a full ocular exam, full cycloplegic refraction, visual acuity measurement, ocular motility and strabismus evaluation. All data were organized in tables and graphs and analyzed by statistician. Results: Our preliminary results will be discussed on spot by our corresponding author. Conclusions: We focused on this study on utilizing various examination techniques which enhanced our results and highlighted a distinguished correlation between amblyopia and its’ causes. This paper recommendation emphasizes on critical testing protocols to be followed among amblyopic patient, especially in tertiary care centers.

Keywords: amblyopia, amblyopia causes, amblyopia diagnostic criterion, amblyopia prevalence, Saudi Arabia

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Authors: Fatma Sümer

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Introduction: This case report aims to report myopic anisometropia with copy-image in monozygotic twins. Methods: In February 2021, a 6-year-old identical twin was seen, who was referred to us with the diagnosis of amblyopia in their left eye from an external center. Both twins had a full ophthalmic examination, which included visual acuity testing, ocular motility testing, cycloplegic refraction, and fundus examination. Results: On examination, “copy image” myopic anisometropia was discovered. Twin 1 had anisometropia with myopic astigmatism in the left eye. His cycloplegic refraction was +1.00 (-0.75x 75) in the right eye and -8.0 (-1.50x175) in the left eye. Similarly, twin 2 had anisometropia with myopic astigmatism in the left eye. His cycloplegic refraction was -7.75 (-1.50x180) in the left eye and +1.25 (-0.75x90 ) in the right eye. The best-corrected visual acuity was 20/60 in the amblyopic eyes and 20/20 in the unaffected eyes. There was no ocular deviation. In either patient, a slit-lamp microscopic examination revealed no abnormalities in the anterior parts of either eye. Fundoscopic examination revealed no abnormalities. No abnormal ocular movements were demonstrated. Conclusion: As far as we have reviewed in the literature, previous studies with twins were mostly concerned with mirror-effect myopic anisometropia and myopic anisometropia, whereas ipsilateral amblyopia and anisometropia were not reported in monozygotic twins. This case underscores the possible genetic basis of myopic anisometropia.

Keywords: amblyopia, anisometropia, myopia, twins

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Authors: Mohammad Maeiyat, Ali Maeiyat Ivatlou, Rasul Fani Khiavi, Abouzar Maeiyat Ivatlou, Parya Maeiyat

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Purpose: Considering the fact that visual impairment is still one of the countries health problem, this study was conducted to determine the causes of blindness and low vision in visually impaired membership of Ardabil Province welfare organization. Methods: The present study which was based on descriptive and national-census, that carried out in visually impaired population supported by welfare organization in all urban and rural areas of Ardabil Province in 2013 and Collection of samples lasted for 7 months. The subjects were inspected by optometrist to determine their visual status (blindness or low vision) and then referred to ophthalmologist in order to discover the main causes of visual impairment based on the international classification of diseases version 10. Statistical analysis of collected data was performed using SPSS software version 18. Results: Overall, 403 subjects with mean age of years participated in this study. 73.2% were blind, 26.8 % were low vision and according gender grouping 60.50 % of them were male, 39.50 % were female that divided into three groups with the age level of lower than 15 (11.2%) 15 to 49 (76.7%), and 50 and higher (12.1%). The age range was 1 to 78 years. The causes of blindness and low vision were in descending order: optic atrophy (18.4%), retinitis pigmentosa (16.8%), corneal diseases (12.4%), chorioretinal diseases (9.4%), cataract (8.9%), glaucoma (8.2%), phthisis bulbi (7.2%), degenerative myopia (6.9%), microphtalmos ( 4%), amblyopia (3.2%), albinism (2.5%) and nistagmus (2%). Conclusion: in this study the main causes of visual impairments were optic atrophy and retinitis pigmentosa, thus specific prevention plans can be effective in reducing the incidence of visual disabilities.

Keywords: blindness, low vision, welfare, ardabil

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Authors: Abir Dey, Shams Noman

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Introduction: Offshore Island is the remote and isolated area from the terrestrial mainland. They are deprived of their needs. The children from an offshore island are usually underserved in the case of health care because it is a remote area where the health care systems are quite poor compared to mainland. So, the proper information is required for appropriate planning to reduce underlying causes behind visual deprivation among the surviving children of the Offshore Island. Purpose: The purpose of this study was to determine ocular morbidities, knowledge, and barriers of eye care services among children in an Offshore Island. Methods: The study team visited, and all data were collected from different rural communities at Sandwip Upazila, Chittagong district for screening the children aged 5-16 years old by doing spot examination. The whole study was conducted in both qualitative and quantitative methods. To determine ocular status of children, examinations were done under skilled Ophthalmologists and Optometrists. A focus group discussion was held. The sample size was 490. It was a community based descriptive study and the sampling method was purposive sampling. Results: In total 490 children, about 56.90% were female and 43.10% were male. Among them 456 were school-going children (93.1%) and 34 were non-school going children (6.9%). In this study the most common ocular morbidity was Allergic Conjunctivitis (35.2%). Other mentionable ocular morbidities were Refractive error (27.7%), Blepharitis (13.8%), Meibomian Gland Dysfunction (7.5%), Strabismus (6.3%) and Amblyopia (6.3%). Most of the non-school going children were involved in different types of domestic work like farming, fishing, etc. About 90.04% children who had different ocular abnormalities could not attend to the doctor due to various reasons. Conclusions: The ocular morbidity was high in rate on the offshore island. Eye health care facility was also not well established there. Awareness should be raised about necessity of maintaining hygiene and eye healthcare among the island people. Timely intervention through available eye care facilities and management can reduce the ocular morbidity rate in that area.

Keywords: morbidities, screening, barriers, offshore island, knowledge

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Authors: Anoop T. R., Otman Basir, Robert F. Hess, Eileen E. Birch, Brooke A. Koritala, Reed M. Jost, Becky Luu, David Stager, Ben Thompson

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Strabismus refers to a misalignment of the eyes. Early detection and treatment of strabismus in childhood can prevent the development of permanent vision loss due to abnormal development of visual brain areas. We developed a two-stage method for strabismus detection and classification based on photographs of the face. The first stage detects the presence or absence of strabismus, and the second stage classifies the type of strabismus. The first stage comprises face detection using Haar cascade, facial landmark estimation, face alignment, aligned face landmark detection, segmentation of the eye region, and detection of strabismus using VGG 16 convolution neural networks. Face alignment transforms the face to a canonical pose to ensure consistency in subsequent analysis. Using facial landmarks, the eye region is segmented from the aligned face and fed into a VGG 16 CNN model, which has been trained to classify strabismus. The CNN determines whether strabismus is present and classifies the type of strabismus (exotropia, esotropia, and vertical deviation). If stage 1 detects strabismus, the eye region image is fed into stage 2, which starts with the estimation of pupil center coordinates using mask R-CNN deep neural networks. Then, the distance between the pupil coordinates and eye landmarks is calculated along with the angle that the pupil coordinates make with the horizontal and vertical axis. The distance and angle information is used to characterize the degree and direction of the strabismic eye misalignment. This model was tested on 100 clinically labeled images of children with (n = 50) and without (n = 50) strabismus. The True Positive Rate (TPR) and False Positive Rate (FPR) of the first stage were 94% and 6% respectively. The classification stage has produced a TPR of 94.73%, 94.44%, and 100% for esotropia, exotropia, and vertical deviations, respectively. This method also had an FPR of 5.26%, 5.55%, and 0% for esotropia, exotropia, and vertical deviation, respectively. The addition of one more feature related to the location of corneal light reflections may reduce the FPR, which was primarily due to children with pseudo-strabismus (the appearance of strabismus due to a wide nasal bridge or skin folds on the nasal side of the eyes).

Keywords: strabismus, deep neural networks, face detection, facial landmarks, face alignment, segmentation, VGG 16, mask R-CNN, pupil coordinates, angle deviation, horizontal and vertical deviation

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Authors: Rita Alfattal, Maryam Alfarhan, Adeeb M. Algaith, Buthaina Albash, Reem M. Elshafie, Asma Alshammari, Ahmad Alahmad, Fatima Dashti, Rasha Alsafi, Hind Alsharhan

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Defects of respiratory chain complex III (CIII) result in characteristic but rare mitochondrial disorders associated with distinct neuroradiological findings. The underlying molecular defects affecting mitochondrial CIII assembly factors are few and yet to be identified. LYRM7 assembly factor is required for proper CIII assembly where it acts as a chaperone for the Rieske iron‐sulfur (UQCRFS1) protein in the mitochondrial matrix and stabilizing it. We present here the seventeenth individual with LYRM7-associated mitochondrial leukoencephalopathy harboring a previously reported rare pathogenic homozygous LYRM 7 variant, c.2T>C, (p.Met1?). Like previously reported individuals, our 4-year-old male proband presented with recurrent metabolic and lactic acidosis, encephalopathy, and myopathy. Further, he has additional, previously unreported features, including an acute stroke like episode with bilateral central blindness and optic neuropathy, recurrent hyperglycemia and hypertension associated with metabolic crisis. However, he has no signs of psychomotor regression. He has been stable clinically with residual left-sided reduced visual acuity and amblyopia, and no more metabolic crises for 2-year-period while on the mitochondrial cocktail. Although the reported brain MRI findings in other affected individuals are homogenous, it is slightly different in our index, revealing evidence of bilateral almost symmetric multifocal periventricular T2 hyperintensities with hyperintensities of the optic nerves, optic chiasm, and corona radiata but with no cavitation or cystic changes. This report describes new clinical and radiological findings of LYRM7-associated disease. The report also summarizes the clinical and molecular data of previously reported individuals describing the full phenotypic spectrum.

Keywords: LYRM7 gene defect, mitochondrial disease, , lactic acidosis, , genetic disorder

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Authors: Henok Biruk Alemayehu, Kalkidan Berhane Tsegaye, Fozia Seid Ali, Nebiyat Feleke Adimassu, Getasew Alemu Mersha

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Background: Strabismus is a visual disorder where the eyes are misaligned and point in different directions. Untreated strabismus can lead to amblyopia, loss of binocular vision, and social stigma due to its appearance. Since it is assumed that knowledge is pertinent for early screening and prevention of strabismus, the main objective of this study was to assess knowledge and attitudes toward strabismus in Woreta town, Northwest Ethiopia. Providing data in this area is important for planning health policies. Methods: A community-based cross-sectional study was done in Woreta town from April–May 2020. The sample size was determined using a single population proportion formula by taking a 50% proportion of good knowledge, 95% confidence level, 5% margin of errors, and 10% non- response rate. Accordingly, the final computed sample size was 424. All four kebeles were included in the study. There were 42,595 people in total, with 39,684 adults and 9229 house holds. A sample fraction ’’k’’ was obtained by dividing the number of the household by the calculated sample size of 424. Systematic random sampling with proportional allocation was used to select the participating households with a sampling fraction (K) of 21 i.e. each household was approached in every 21 households included in the study. One individual was selected ran- domly from each household with more than one adult, using the lottery method to obtain a final sample size. The data was collected through a face-to-face interview with a pretested and semi-structured questionnaire which was translated from English to Amharic and back to English to maintain its consistency. Data were entered using epi-data version 3.1, then processed and analyzed via SPSS version- 20. Descriptive and analytical statistics were employed to summarize the data. A p-value of less than 0.05 was used to declare statistical significance. Result: A total of 401 individuals aged over 18 years participated, with a response rate of 94.5%. Of those who responded, 56.6% were males. Of all the participants, 36.9% were illiterate. The proportion of people with poor knowledge of strabismus was 45.1%. It was shown that 53.9% of the respondents had a favorable attitude. Older age, higher educational level, having a history of eye examination, and a having a family history of strabismus were significantly associated with good knowledge of strabismus. A higher educational level, older age, and hearing about strabismus were significantly associated with a favorable attitude toward strabismus. Conclusion and recommendation: The proportion of good knowledge and favorable attitude towards strabismus were lower than previously reported in Gondar City, Northwest Ethiopia. There is a need to provide health education and promotion campaigns on strabismus to the community: what strabismus is, its’ possible treatments and the need to bring children to the eye care center for early diagnosis and treatment. it advocate for prospective research endeavors to employ qualitative study design.Additionally, it suggest the exploration of studies that investigate causal-effect relationship.

Keywords: strabismus, knowledge, attitude, Woreta

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