Amblyopia and amblyopia treatment study

In 1997, the Pediatric Eye Disease Investigator Group (PEDIG) was formed to conduct clinical research in eye disorders that affect children.1,2 The primary focus of PEDIG involves studies that can be conducted through simple protocols with limited data collection and implemented by both university-based and community-based pediatric eye care practitioners as part of their routine practice. As of October 1, 2003, 135 investigators at 97 sites in North America have participated in at least 1 PEDIG study. A major focus of PEDIG has been the evaluation of different treatment modalities for amblyopia (the Amblyopia Treatment Study). Amblyopia was selected for study because it is the most common cause of monocular visual impairment in children and young and middle-aged adults,3,4 and opinions vary on the appropriate treatment regimens. Three randomized trials have been completed thus far, and 3 trials and 2 observational studies are currently in progress. The first PEDIG amblyopia trial compared patching of the sound eye versus instillation of atropine drops in the sound eye as treatments for moderate amblyopia (20/40 to 20/100) in children 3 to 7 years old.5–9 Amblyopia was due to unequal refractive error, strabismus, or both. Atropine blurs the vision in the sound eye through its cycloplegic effect that can last, at least partially, for up to 14 days. The group of children randomized to atropine treatment received 1 drop of 1% atropine in the sound eye daily; if by 4 months acuity had not reached 20/30 or improved from baseline by ≥3 lines, then any far-sighted correction in the spectacle lens of the sound eye was removed to augment the effect of the atropine. The patching group was initially prescribed daily patching for a minimum of 6 hours up to all waking hours at investigator … Address correspondence to Graham E. Quinn, MD, MSCE, Division of Pediatric Ophthalmology, Children’s Hospital of Philadelphia, One Children’s Center, Philadelphia, PA 19104. E-mail: quinn{at}email.chop.edu

In Reply.—Dr Lempert's recent letter describes similar issues to those he has raised in previous letters to the editor. We have responded to these issues in the past and will reiterate our responses. The Amblyopia Treatment Studies (ATS) are a series of randomized, clinical trials designed to answer questions about the optimal management of amblyopia.1–9 The studies are conducted by the Pediatric Eye Disease Investigator Group (PEDIG), a large group of pediatric ophthalmologists and optometrists based in both university and community settings.10,11 Dr Lempert contends that a significant weakness of the ATS is the inclusion of only a small number of subjects from each center and suggests that this reflects a selection bias. In fact, by involving a larger number of participating centers, we are able to achieve a sample size sufficient to make statistically valid observations more rapidly than could be accomplished if only a limited number of centers participated. In addition, including a large number of diverse centers increases generalizability of the results.We agree that a clinical trial can never completely reflect daily practice. The informed-consent process itself probably educates parents of amblyopic children more than the usual instructions provided during routine care, and this may affect treatment compliance. Nevertheless, we deliberately designed the ATS to be conducted in a “real-world” environment as much as possible, with the exception of randomization of treatment assignment and a standardized protocol for assessing visual acuity.Dr Lempert contends that an additional weakness of the ATS was the lack of an untreated control group. When we designed our early studies, PEDIG investigators concluded that they could not maintain clinical equipoise (a balance between potential benefit and potential harm between treatment groups) in trials that required maintaining the child in an assigned untreated group for 4 to 6 months. However, in our analysis of these early studies, we did not find a significantly different treatment effect in older children, compared with younger children, within our 3- to 7-year age range. These new data have allowed us to design a short-duration study incorporating an untreated control group. We are currently conducting that randomized trial, comparing visual acuity improvement over 5 weeks between an untreated group and a group assigned to 2 hours of daily patching.Dr Lempert suggests that the observed improvement in visual acuity could occur because of maturation or a learning effect. In our completed ATS, the average improvement of amblyopic eye acuity ranged from 2.4 to 4.8 lines6,9 over 4 to 6 months. This improvement far exceeded that expected from a learning effect. It is important to note that the visual acuity improvement in amblyopic eyes also far exceeded the improvement seen in the fellow sound eyes over the same time period.Dr Lempert raises the possibility that organic causes may explain many cases of amblyopia observed in clinical studies. Although we cannot exclude rare cases of organic visual loss within our studies, we note that many of the amblyopic eyes in our studies improved to within the normal range. Thus, the presence of an abnormality of the optic nerve does not negate the importance of successful amblyopia treatment. Additional longer-term studies are needed to define whether these eyes become truly normal and, if so, whether they remain normal. We are currently conducting examinations on patients who were enrolled in our study of atropine versus patching and have reached the age of 10 years. We also plan to reexamine these patients at 15 years old.Dr Lempert suggests that we include biometry and disk imaging in future ATS. Using such technology would limit the number of centers that could participate in the studies and also exclude from participation a large number of the younger children who can provide recognition acuity and therefore participate in a randomized treatment trial but who would be unable to cooperate for biometric studies or fundus photography. Such morphologic studies are warranted but do not fit into our study design of large simple trials.Finally, Dr Lempert suggests that we have accepted “occlusion as the unquestioned mainstay of treatment for unilateral poor vision.” This is not true. However, in the past, we noted that patching is the mainstay of amblyopia therapy in North America. PEDIG studies have already investigated use of a pharmacologic agent, topical atropine, in the treatment of amblyopia.3 Thus far, we have concluded that both atropine and patching are appropriate for initial treatment of moderate amblyopia. Future randomized, clinical trials are needed to investigate additional modalities of amblyopia treatment in current use, including optical penalization, blurring filters, and systemic drugs.

To investigate the treatment policy for amblyopia in Japan as of 2017 through a survey of multiple facilities and to compare the findings with those obtained by the Amblyopia Treatment Study (ATS) of the Pediatric Eye Disease Investigator Group. Questionnaire survey study. A questionnaire was sent to 181 facilities where patients with amblyopia are being treated. The outcomes of the present survey were compared with the results of the ATS study, and the coincidence rates were evaluated. The questionnaire response rate was 68.0%. The treatment plan that showed the highest agreement between the outcomes of the ATS study and the present study was whether or not treatment was to be given to patients aged 10-15years who had received no previous treatment; 90% of the facilities answered that they would provide treatment to such patients as well. The next highest agreement was the future treatment of amblyopia with stable visual acuity in the affected eye; 82.6% of the facilities responded that they would reduce the occlusion time. On the other hand, the lowest agreement rate was the follow-up period of the refractive correction for moderate anisometropic amblyopia. The ATS showed "4 months," whereas most of the facilities in the present survey replied "3 months." The agreement rate was 10.8%. The amblyopia treatment in Japan survey did not always agree with the research results of the ATS. Japanese ophthalmologists tend to make treatment plans for amblyopia according to their clinical experience.

IntroductionThe Pediatric Eye Disease Investigator Group (PEDIG), formed in 1997, has been dedicated to clinical research of eye diseases affecting children. Over the last three years, PEDIG has studied the efficacy of amblyopia treatment regimes, and has followed the long-term outcomes of these regimes. These studies are known as the Amblyopia Treatment Studies (ATS) and have been sorted into eight categories. Four of these have been published and four are still awaiting publication.MethodA survey of ophthalmologists and orthoptists attending a seminar in British Columbia, Canada. They were questioned as to how they treat amblyopia in light of the PEDIG studies.ResultsNinety percent continue to use patching as their first method of treatment in moderate amblyopia. Over 50% will patch four hours/day or more to begin treatment and 83% will use near exercises to augment the patching. Two thirds will begin patching six or more hours/day in patients with severe amblyopia. Those that use atropine, use it daily rather than on weekends. Most felt that amblyopia could be treated to age 12 years and some thought it could be treated to 14 years.ConclusionMost ophthalmologists and orthoptists taking the survey have not significantly changed their approach to amblyopia treatment in light of the recent PEDIG studies.

The Pediatric Eye Disease Investigator Group (PEDIG) is a network of university-based and community-based pediatric eye care practitioners that is conducting multiple clinical research studies. The group has conducted the Congenital Esotropia Observational Study, which assessed the early course of esotropia in infants, and the Amblyopia Treatment Studies, a series of randomized trials, the first of which compared atropine and patching for treatment of moderate amblyopia in children 3 to <7 years old. Herein, the results of these studies are summarized, and the current and future studies of the group are described.

Visual impairment and blindness are serious social and health problems in the world. 1992 classification of visual disorders by World Health Organization has recently been implemented. The goal of this study was to determine common causes of visual impairment and blindness in the region of Eastern Herzegovina. In this population based study we have analyzed medical records stored in the regional Association of Visually Impaired and Blind Persons of the Republic of Srpska (Trebinje, Bileća, Foca, Eastern Sarajevo). The analysis included sex and age distribution of registered population, classification and leading causes of visual disability and blindness. RESULTS There are 298 registered persons with visual disability and blindness in the region of Eastern Herzegovina and Eastern Sarajevo. The prevalence of visual impairment and blindness in the aforementioned region is 0.1%. Among the studied population, there are more males than females with visual disability or blindness (56% versus 44%). Most (78%) of registered persons are blind, and only 22% are visualy impaired. 43% of registered population are in the IV category and only 8.38% are registered in the II category. Only 2% of registered population are children. Common causes of visual disability and blindness in the region of Eastern Herzegovina are: glaucoma (22%), cataract (17%), myopia alta (13%), diabetic retinopathy (12%) and ocular trauma (11). Common causes of children's visual impairment include. optic nerve anomalies, congenital cataract and premature retinopathy. Compared with literature data, common causes of blindness and visual impairment in the region of Eastern Herzegovina do not differ significantly from those in other regions. Registration is based on the WHO model, but it is possible only by performing active epidemiological studies.

Purpose:To analyze applications for blindness certificates to find causes of visual impairment (VI), handicap, and blindness in a tertiary hospital of Bihar.Methods:Applications for blindness certificates were analyzed over a two-year period. The main cause of blindness, visual handicap, and VI in these applications was ascertained by age group and etiology. VI disability percentages and definitions proposed by Governmen of India (category 0–4; 20–100%) were used to categorize and give percentage to all applicants. Results were compared with data from studies on blindness certificates and population based studies.Results:In total, 203 applicants were reviewed. Mean age was 23.5 ± 7.9 years. Overall, most common cause of visual handicap (40–100% impairment) and blindness (75–100% impairment) was macular pathology (P<.05), while most common cause of overall VI (20–100% impairment) was amblyopia. In age group 0–15 years, most common causes of blindness/visual handicap were congenital globe and hereditary retinal or optic nerve disorders (P = 0.016). In age group 16–30 years, macular pathology was the most common cause of visual handicap [P = 0.007], while amblyopia was the most common cause of VI [P = 0.00]. Between 31 and 45 years of age group, corneal scar in one eye was the most common cause of VI, while macular scar in both eyes was the most common cause of visual handicap. Glaucoma and diabetic retinopathy were the most common causes of blindness/visual handicap between 46 and 65 years and above 65 years of age, respectively. Data about causes of VI such as amblyopia, complicated cataract surgery, and one eyed blindness could not be ascertained by analyzing blindness certificate alone.Conclusion:Data from applications for blindness certificates provide valuable information regarding different causes of VI that might otherwise not be eligible for blindness certification and provide an insight into the overall trends in disease profile and service delivery.

To describe the prevalence, diagnoses and aetiologies of visual impairment in children with developmental delay (DD) in a Danish county with a population of 618 000 citizens. We carried out a cross-sectional study in Copenhagen County of children aged 4-15 years with profound to borderline DD (IQ <or= 80). Children were located through school psychologists or paediatric clinics. The number of children with DD was estimated using the capture-recapture method. A total of 1126 children fulfilled the inclusion criteria, corresponding to 97.7% of the estimated number of children with DD in the county. Ophthalmological examinations were performed in 923 children. The prevalence of visual impairment was 10.5% in the study group and 22.4% in those with an IQ <or= 50. The diagnoses were predominantly cerebral visual impairment, optic atrophy, retinal dystrophies and congenital nystagmus. The aetiology of visual impairment was prenatal in 54 children, perinatal in 29 children and postnatal in seven children. Visual impairment is highly increased in children with DD and is correlated to low IQ.

Atropine Regimens for Amblyopia: Author reply

Refractive error is one of the major causes of blindness and visual impairment in children; but community based studies are scarce especially in rural parts of Ethiopia. So, this study aims to assess the prevalence of refractive error and its magnitude as a cause of visual impairment among school-age children of rural community. This community-based cross-sectional descriptive study was conducted from March 1 to April 30, 2009 in rural villages of Goro district of Gurage Zone, found south west of Addis Ababa, the capital of Ethiopia. A multistage cluster sampling method was used with simple random selection of representative villages in the district. Chi-Square and t-tests were used in the data analysis. A total of 570 school-age children (age 7-15) were evaluated, 54% boys and 46% girls. The prevalence of refractive error was 3.5% (myopia 2.6% and hyperopia 0.9%). Refractive error was the major cause of visual impairment accounting for 54% of all causes in the study group. No child was found wearing corrective spectacles during the study period. Refractive error was the commonest cause of visual impairment in children of the district, but no measures were taken to reduce the burden in the community. So, large scale community level screening for refractive error should be conducted and integrated with regular school eye screening programs. Effective strategies need to be devised to provide low cost corrective spectacles in the rural community.

Long-term Outcomes of Photorefractive Keratectomy for Anisometropic Amblyopia in Children

Background:To plan and implement appropriate management of patients with blindness and visual impairment (VI) requires the knowledge of the common presenting causes.Aim:The aim of the following study is to determine the common causes of VI in adults and develop a template for eye care delivery.Materials and Methods:A retrospective descriptive analysis of subjects aged 17 years and above who attended LAUTECH Teaching Hospital eye clinic between October 2012 and March 2013. Information on demographic data, visual acuity, anterior and posterior segment examinations, and refraction were obtained from patients’ records. Statistical Package for the Social Sciences version 16. 2, USA was used for descriptive analysis. Chi-square, P values and confidence intervals (CI) were derived for statistical significance.Results:A total of 617 cases were reviewed including 306/617 (49.6%) males and 311/617 (50.4%) females. The frequently occurring age-groups were the 51-60 year 120/617 (19.4%) and the 61-70 year 115/617 (18.6%). The common causes of blindness and VI were cataract 225/617 (36.5%, CI: 32.7-40.3), glaucoma 124/617 (20.1%, CI: 16.93-23.25), refractive errors 119/617 (19.3%, CI: 16.17-22.4); trauma and cornea opacities 14/617 (6.1%) each. Refractive error 6/176 (3.4%) was a significant cause of blindness in this study. χ2 = 33.68, P < 0.001. More females presented with refractive errors 79/311 (66.4%), while more males presented with trauma 32/306 (78.0%). χ2 = 186.47, P < 0.001.Conclusions:The common causes of VI are avoidable. Planning for best practice methods, purchase of equipment/instruments, consumables, drugs, and manpower development is required. Establishment of low-cost cataract surgical and refractive services could reduce their incidence.

Purpose: To determine the prevalence and causes of visual impairment among children aged 7 years and below in a tertiary eye care centre in Kuala Lumpur, Malaysia.&#x0D; Study design: Cross-sectional retrospective study.&#x0D; Methods: Medical records of all children aged 7 years and below who attended the paediatric ophthalmology clinic in a tertiary eye care centre in 2020 were reviewed.&#x0D; Results: In 2020, 2,460 children were seen in the clinic, of whom 549 (22.3%) presented with visual impairment. At the time of presentation, 73.2% of the visually impaired children were diagnosed with blindness; of these children, 62.8% were under 1 year old. The percentage of treatable causes of visual impairment was 38.4%, while 31.1% of them were preventable. The most common causes of visual impairment were cerebral visual impairment (24.2%), congenital cataract (16.6%), and retinoblastoma (6.2%).&#x0D; Conclusion: More than half of the causes of childhood visual impairment were preventable or treatable. The majority of children were under 1 year old. Cerebral visual impairment was the main cause of visual impairment. This study highlights the importance of early screening and intervention programs to prevent childhood visual impairment.

Visual Acuity Testability in African-American and Hispanic Children: The Multi-Ethnic Pediatric Eye Disease Study

BackgroundTo report the prevalence and causes of visual impairment in seven‐year‐old children in Iran and its relationship with socio‐economic conditions.MethodsIn a cross‐sectional population‐based study, first‐grade students in the primary schools of eight cities in the country were randomly selected from different geographic locations using multistage cluster sampling. The examinations included visual acuity measurement, ocular motility evaluation, and cycloplegic and non‐cycloplegic refraction. Using the definitions of the World Health Organization (presenting visual acuity less than or equal to 6/18 in the better eye) to estimate the prevalence of vision impairment, the present study reported presenting visual impairment in seven‐year‐old children.ResultsOf 4,614 selected students, 4,106 students participated in the study (response rate 89-per cent), of whom 2,127 (51.8-per cent) were male. The prevalence of visual impairment according to a visual acuity of 6/18 was 0.341-per cent (95 per cent confidence interval 0.187–0.571); 1.34-per cent (95 per cent confidence interval 1.011–1.74) of children had visual impairment according to a visual acuity of 6/18 in at least one eye. Sixty‐six (1.6-per cent) and 23 (0.24-per cent) children had visual impairment according to a visual acuity of 6/12 in the worse and better eye, respectively. The most common causes of visual impairment were refractive errors (81.8-per cent) and amblyopia (14.5-per cent). Among different types of refractive errors, astigmatism was the main refractive error leading to visual impairment. According to the concentration index, the distribution of visual impairment in children from low‐income families was higher.ConclusionThis study revealed a high prevalence of visual impairment in a representative sample of seven‐year‐old Iranian children. Astigmatism and amblyopia were the most common causes of visual impairment. The distribution of visual impairment was higher in children from low‐income families. Cost‐effective strategies are needed to address these easily treatable causes of visual impairment.