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PubMed2004

A retrospective review of the associations between amblyopia type, patient age, treatment compliance and referral patterns.

AIM: To review presenting ages, referral sources, amblyopia type and treatment compliance in children attending a typical public hospital ophthalmology clinic with no formal amblyopia screening program in place. METHODS: One hundred and twenty-seven children attending the outpatients clinics of The Children's Hospital at Westmead for amblyopia management between January 2001 and May 2003 were reviewed. Presenting age, amblyopia type, referral source, treatment prescribed and compliance achieved were analysed using means, 95% confidence intervals (CI), and Mantel-Haenszel chi2 statistic. RESULTS: General practitioners and paediatricians provided most referrals. The mean presenting age was 32.9 (95% CI 29.0-36.9) months. There was no significant association between presenting age and amblyopia type (chi2 = 6.00, P = 0.11, d.f. = 3), but a trend was found with deprivation amblyopia identified earliest, and pure anisometropic amblyopia identified latest (chi2 = 5.65, P = 0.02, d.f. = 1). Compliance to patching did not differ significantly between sexes, with calculated aggregate compliance of 67.3% (95% CI: 59-75%) for boys and 66.3% (95% CI: 60-73%) for girls. Compliance to patching also did not differ significantly between amblyopia types (chi2 = 3.61, P = 0.3, d.f. = 3). Compliance was best among younger and older children, and worst among those aged 15-30 months. There was no association between patching compliance and treatment duration. CONCLUSION: Amblyopia is a preventable form of blindness. A multidisciplinary approach must be taken. Resources and education should be targeted at general practitioners and paediatricians who have the greatest opportunities to perform amblyopia screening. Teachers are an important resource in identifying cases missed at previous informal screening opportunities. Amblyopia treatment must be intensified and individualized between the ages of 15-30 months when compliance is poorest.

Age Distribution↗
PubMed2005

Amblyopia: prevalence, natural history, functional effects and treatment.

Amblyopia, defined as poor vision due to abnormal visual experience early in life, affects approximately three per cent of the population and carries a projected lifetime risk of visual loss of at least 1.2 per cent. The presence of amblyopia or its risk factors, mainly strabismus or refractive error, have been primary conditions targeted in childhood vision screenings. Continued support for such screenings requires evidence-based understanding of the prevalence and natural history of amblyopia and its predisposing conditions, and proof that treatment is effective in the long term with minimal negative impact on the patient and family. This review summarises recent research relevant to the clinical understanding of amblyopia, including prevalence data, risk factors, the functional impact of amblyopia and optimum treatment regimes and their justification from a vision and life skills perspective. Collectively, these studies indicate that treatment for amblyopia is effective in reducing the overall prevalence and severity of visual loss from amblyopia. Correction of refractive error alone has been shown to significantly reduce amblyopia and less frequent occlusion can be just as effective as more extensive occlusion. Occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life, and these factors should be considered in prescribing treatment, particularly because of their influence on compliance. Ongoing treatment trials are being undertaken to determine both the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion. This review highlights the expansion of current knowledge regarding amblyopia and its treatment to help clinicians provide the best level of care for their amblyopic patients that current knowledge allows.

Adaptation, Psychological↗
PubMed2005

Treatment of unilateral amblyopia: factors influencing visual outcome.

PURPOSE: To identify factors that influence the outcome of treatment for unilateral amblyopia, as a part of the Monitored Occlusion Treatment of Amblyopia Study (MOTAS). METHODS: This was an intervention study consisting of three nonoverlapping phases: "Baseline", "refractive adaptation" (18 weeks of full-time spectacle wear), and "occlusion" (6 hours of patching per day, objectively monitored). Condition factors: type of amblyopia, age of participant, initial severity of amblyopia, fixation, and binocular vision status; treatment factors: refractive adaptation and occlusion (total dose [hours] and dose rate [hours per day]) were assessed for their influence on visual outcome. Visual outcome was expressed in three ways: logMAR (logarithm of the minimum angle of resolution) change, residual amblyopia, and proportion of the deficit corrected. RESULTS: The study included 85 participants (mean age, 5.1 +/- 1.4 years) with amblyopia associated with strabismus (n = 32) or anisometropia (n = 20) or associated with both anisometropia and strabismus (n = 33). Treatment factors: cumulative occlusion dose exceeding 50 hours, and dose rates > or =1 hour per day resulted in (P < or = 0.01) lower residual amblyopia and a greater proportion of the deficit corrected. Condition factors associated with poor outcome (high residual amblyopia) were presence of eccentric fixation, severe initial amblyopia, and no binocular vision. CONCLUSIONS: Factors influencing outcome with treatment for amblyopia are occlusion dose (the rate of delivery and cumulative dose worn), the initial severity of the amblyopia, binocular vision status, fixation of the amblyopic eye, and the age of the subject at the start of treatment.

Age Factors↗
PubMedDate not supplied

Upper age limit for the development of amblyopia.

The medical records of 64 patients between 1 and 11 years old with known onset of an amblyopia-inducing condition were retrospectively reviewed to determine the upper age limit for the development of amblyopia. Thirty seven patients (group 1) developed amblyopia and 27 patients (group 2) did not. The mean patient age at the onset of the amblyopia-inducing condition was 41.0 months (2.90 SE) for group 1 and 92.3 months (4.02 SE) for group 2. The difference was statistically significant (P = .0001). No patient developed amblyopia after 73 months of age. The duration of the amblyopia-inducing condition and the type of amblyopia-inducing condition were not significantly different between the two groups. The age of the patient when exposed to an amblyopia-inducing condition is the most important determinant for the development of amblyopia. Patients 6 years or older with a normal visual system have a low probability of developing amblyopia following the onset of an amblyopia-inducing condition.

Age of Onset↗
PubMed2003

[Clinical study of visual plasticity in teenage and adults with amblyopia].

OBJECTIVE: Human visual plasticity was studied by the observation of the effects of treatment in teenage and adult amblyopia. METHODS: One hundred and two cases (125 eyes) were diagnosed as amblyopia according to the national criteria of amblyopia. These patients were divided into teenage group (15 - 17 years old, 47 cases and 57 eyes) and adult group (18 - 45 years old, 55 cases and 68 eyes). Eye examination, including best correct visual acuity, laser interference fringes visual acuity (IVA), degree and patterns of amblyopia, and nature of fixation were performed in these two groups before amblyopic treatment. Patients were treated with correct spectacle, optical and drug penalization (including far and near penalization, as well as light penalization), combined with occlusion and assisted with red light pleoption. All patients were followed up for 1 - 5 years, with an average of 2.9 years. RESULTS: Fifty five eyes (44%) were cured (23 eyes recovered, 32 eyes basically cured), 37 eyes (29.6%) were improved, 33 eyes (26.4%) were nullified and the total improvement rate was 73.6%. Different ages did not influence the results of treatment significantly (P > 0.05). Outcome of foveal fixation and parafoveal fixation was much better than that of paramacular fixation and peripheral fixation (P < 0.005). The curative efficiency of amblyopia was also dependent on the degree of amblyopia (P < 0.005). Curative effects of ametropic and anisometropic amblyopia were better than that of strabismic and deprivable amblyopia (P < 0.01). Visual acuity predicted by IVA before the treatment was the same as real results after the treatment in 112 eyes among 125 eyes (92.8%). The correlation efficient between the predicted and real vision was statistically significant (r = 0.886 2, P < 0.000 1). CONCLUSIONS: Vision in most teenage and adult amblyopia can be improved by amblyopic therapy. Therefore, it seems that human visual plasticity exists permanently during the whole life. Visual acuity after the treatment can be predicted by pre-treatment IVA. Results of amblyopia treatment are closely related with the degree and patterns of amblyopia and are also dependent on the cooperation of the patients.

Adolescent↗
PubMed1983

[Strabismus and amblyopia. Value of their early detection].

The authors emphasize the importance of the relations between strabismus and amblyopia. Strabismus is often the symptom which leads to the discovery of amblyopia. Amblyopia may cause strabismus, as in organic amblyopias induced by congenital lesions of the retina or visual pathways, and visual deprivation amblyopias due to corneal opacities and/or congenital cataracts. Unilateral clouding of normally transparent media (cornea, lens, vitreum) prevents normal stimulation of the retina which is necessary to the development of binocular vision. Anisometropic amblyopias also belong to this category. More often, amblyopia is the consequence of strabismus: it is then termed "functional strabismic amblyopia". Loss of the parallelism of the two visual axes disrupts the functional balance between the images received from the two eyes. The two images are different; one is suppressed. This suppression may eventually lead to amblyopia. Amblyopia was discovered in 593 of 1 757 studied cases of strabismus. Amblyopia was the cause of strabismus in 87 patients and was functional in the remaining 506. Among these latter, visual acuity was inferior or equal to 1/10 in 241 cases and between 2/10 and 7/10 in 265. 147 children in the first group and 136 in the second could be treated. Among these patients, who were treated before the age of seven, complete recovery was obtained in approximately 1/2 of cases and improvement in more than 1/4 of first group patients and 1/3 of second group patients. Results were all the better that treatment was initiated earlier and that patients were younger.(ABSTRACT TRUNCATED AT 250 WORDS)

Amblyopia↗
PubMed2005

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia.

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia.

Adolescent↗
PubMed2005

Risk factors for amblyopia in congenital anterior lens opacities.

PURPOSE: We sought to identify the features of congenital anterior lens opacities (CALOs), which are associated with increased risk for amblyopia. METHODS: We undertook a retrospective study of 59 patients with CALO from 3 clinical practices. The following variables were examined: type (polar, subcapsular, or pyramidal), location (central, paracentral, or peripheral), diameter, presence of adherent iris tissue, anisometropia (spherical equivalent), unilateral versus bilateral, and presence or absence of amblyopia. Pearson chi-square and independent sample t-tests were conducted to evaluate if any of the aforementioned variables were independently associated with amblyopia. Relative risk was then calculated for significantly related variables (P < 0.05). RESULTS: Amblyopia was present in 17 of 59 patients (28.8%). Patients with amblyopia had a mean anisometropia of 1.23 diopters whereas nonambyopic patients had a mean anisometropia of 0.25 (P = 0.023). The relative risk for amblyopia with anisometropia of one diopter or greater was 6.5 (95% confidence interval = 3.79-7.45). The mean cataract size in the amblyopic eyes was 1.22 mm (range, 0.7-2.0 mm). Mean cataract size in the nonamblyopic eyes was 0.95 mm (range, 0.5-2.0 mm). This difference in mean cataract size was significant with independent sample t-tests (P = 0.02); however, this difference did not remain significant with logistic regression. Cataract size was not a significant relative risk factor for amblyopia. CONCLUSIONS: Our overall incidence of amblyopia was 28.8%. The only variable associated with increased relative risk for amblyopia in this group of patients was anisometropia. Patients with CALO who have anisometropia of 1 diopter or greater are 6.5 times more likely to develop amblyopia.

Amblyopia↗
PubMed1998

Prevalence of amblyopia with anisometropia or strabismus among schoolchildren in the Sultanate of Oman.

PURPOSE: The purpose of this study was to investigate the prevalence of common eye disorders in a nationwide school survey conducted in the Sultanate of Oman. The results presented here are those involving amblyopia induced by strabismus or anisometropia. METHODS: A random selection of primary schools provided a sample that included 49 schools with 6541 children in Grades 1 and 6. Examinations of the eyes of 96%, of these children were conducted doing visual acuity screening to 0.5. All 6292 children had an external eye examination. All children failing the visual acuity test had a complete eye examination. RESULTS: Amblyopia was found in 0.92%, strabismic amblyopia in 0.48%, anisometropic amblyopia in 0.44% and strabismus with or without amblyopia was seen in 0.9%. There was statistically significantly (p<0.05) more amblyopia in 11-12 year olds (Grade 6) when compared with the 6-7 year olds (Grade 1). This difference was only found among the strabismic children. CONCLUSION: When compared to Europe or North America the prevalence of strabismic amblyopia is lower, whereas anisometropic amblyopia occurs with approximately the same frequency. The increase of strabismic amblyopia in the older children indicates a development of amblyopia after the age of 6 to 7 years in an untreated population.

Amblyopia↗
PubMed2000

Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyopia.

PURPOSE: To evaluate the efficacy of a mass screening program for amblyopia and amblyogenic risk factors in infants. METHODS: Since 1968, children between the ages of 1 and 2(1/2) years in the city of Haifa, Israel, have been systematically screened for amblyopia and amblyogenic risk factors. The screening is performed by the Ophthalmology Department of Bnai-Zion Medical Center (formerly known as Rothchild Hospital). In 1995, we compared the prevalence and severity of amblyopia in two populations of 8-year-old children in elementary school: one group was a cohort of 808 children from the city of Haifa and its vicinity, who had been screened in infancy (between 1988 and 1990); and the second group, the control group, was a cohort of 782 children from Hadera and its vicinity, where this early screening program is not conducted. Amblyopia was defined as corrected visual acuity of < or =5/10 (20/40), or >1 line difference in corrected visual acuity between the two eyes. Referral rate, treatment rate, sensitivity, specificity, and positive predictive value and negative predictive value of the screening test in detecting factors that later resulted in the development of amblyopia were examined. RESULTS: The prevalence of amblyopia in the 8-year-old population screened in infancy was found to be 1.0% compared with 2.6% in the 8-year-old population that had not been screened in infancy (P =.0098). The prevalence of amblyopia with visual acuity of < or =5/15 (20/60) in the amblyopic eye was 0.1% in the screened population compared with 1.7% in the non-screened population (P =.00026). In the screened infant population, 3.6% were referred from the screening examination to a confirmatory examination and 2.2% were treated. The screening examination had a sensitivity of 85.7% and a specificity of 98.6% for amblyopia. The positive predictive value of the screening examination was 62.1% and the negative predictive value was 99.6%. CONCLUSIONS: The screening program for amblyopia and amblyogenic risk factors in infants, followed by appropriate treatment, is effective in significantly reducing the prevalence and severity of amblyopia in children.

Amblyopia↗
PubMed2005

Efficacy of occlusion treatment in amblyopia and clinical risk factors affecting the results of treatment.

PURPOSE: To evaluate the factors influencing visual outcome in strabismic, strabismic-anisometropic and anisometropic amblyopia following occlusion treatment. METHODS: Records of 128 pediatric patients who had been treated for amblyopia by occlusion of the fellow eye between March 1992 and March 2003 were reviewed retrospectively. Age and level of visual acuity at initiation of treatment, occlusion time (full-time, part-time or minimal) and type of amblyopia were analyzed for the effect on visual outcome. RESULTS: The mean age of the patients was 5.69 +/- 2.01 years (3 to 12 years). Mean follow-up time was 3 years 2 months (6 months to 10 years). Mean visual acuity improvements were similar for the subtypes of amblyopia (strabismic amblyopia 0.38 +/- 0.29 logMAR units, strabismic-anisometropic amblyopia 0.46 +/- 0.40 logMAR units, anisometropic amblyopia 0.35 +/- 0.24 logMAR units). Level of initial visual acuity, age at initiation of treatment and type of occlusion correlated with the final visual acuity (p = 0.000, p = 0.035, p = 0.012, respectively). When the analysis was performed according to the subtypes of amblyopia, initial visual acuity was the only factor associated with the final visual acuity in all types of amblyopia (p < 0.05). CONCLUSION: The level of initial visual acuity is the most significant factor determining the success of treatment in amblyopia.

Amblyopia↗
PubMed2005

The prevalence of strabismus and amblyopia in Japanese elementary school children.

BACKGROUND: The purpose of this study is to elucidate the prevalence of strabismus and amblyopia in a large population of Japanese elementary school children, from Grade 1 to Grade 6, ages ranging from 6 to 12 years. The School Health Law requires that all pupils in Grade 1 to Grade 6 be examined for vision and eye problems. Visual acuity testing is done by school teachers and eye disease screening by school ophthalmologists. Pupils with suspected ocular diseases are further examined by extramural ophthalmologists and the results reported back to the schools. The schools then summarize and send uncorrected visual acuity and ocular disease incidence, together with other health statistics, to the municipal education committees. The data are forwarded to the Prefecture Governments and finally submitted to the Education Ministry of the Central Government. Both the Prefecture Governments and the Education Ministry publicize the school health statistics on their websites. The prevalence of strabismus and amblyopia remains unknown from these data because both diagnoses are included under the heading, eye diseases. METHODS: Questionnaires asking about the numbers of children with different types of strabismus and amblyopia were sent to all elementary schools in Okayama Prefecture and the results were summarized. RESULTS: The number of children covered by the return of questionnaires was 86,531 (76.4%) of 113,254 total pupils in Grade 1 to Grade 6 in Okayama Prefecture in the year 2003. The total numbers of children with strabismus and amblyopia were 1,112 (1.28%) and 125 (0.14%), respectively. The numbers of children with any type of exotropia and any type of esotropia were 602 (0.69%) and 245 (0.28%), respectively. The major types of strabismus and amblyopia were intermittent exotropia in 109 children (0.12%), accommodative esotropia in 19 children (0.02%), anisometropic amblyopia in 23 children (0.03%), and ametropic amblyopia in 12 children (0.01%). The number of children with strabismus of unknown type was 245 (0.28%) while the number of children with amblyopia of unknown type was 81 (0.09%). CONCLUSIONS: The prevalence rates of strabismus and amblyopia in this population of Japanese elementary school children were lower than those reported in Western countries. The exotropia/esotropia ratio were increased in comparison with past studies in Japan. The school eye doctors need to be more diligent in identifying and diagnosing various types of strabismus and amblyopia in order to contribute to the school vision screening program already in place in Japan

Amblyopia↗
PubMed2005

Factors influencing visual rehabilitation after occlusion therapy in unilateral amblyopia in children.

BACKGROUND & OBJECTIVE: Amblyopia is one of the most common causes of visual impairment in adults and children, and visual loss may be permanent if not treated in time. Though many studies have been done on occlusion therapy which is the mainstay in the treatment of unilateral amblyopia, discrepancies exist in literature about quantification of treatment and follow up measures. The present study was undertaken to evaluate the factors responsible for the successful outcome of treatment and the optimum time required for the same in children with unilateral amblyopia. METHODS: Baseline characteristics of 63 verbal patients with unilateral amblyopia (strabismic, anisometropic, mixed) referred to the Strabismus and Amblyopia Clinic at the Dr Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi between September 2001 to December 2002 who improved to the desired level of visual acuity after treatment for amblyopia in the mentioned time period, were analyzed to assess for factors that directly or indirectly influenced the optimum visual rehabilitation and the average duration of therapy required for the same. The evaluation included assessment of the baseline best-corrected visual acuity (BCVA) and refractive status in both eyes, the age at presentation, the type of amblyopia present, fixation pattern in the amblyopic eye, inter-eye visual acuity difference, and evaluation of compliance through a parental diary system. RESULTS: Baseline BCVA in the amblyopic eye was similar in all the three groups. Patients with anisometropic amblyopia showed a quicker response to therapy. Compliance to treatment was the major factor affecting the overall time required for a successful outcome in most cases. The overall time required for the treatment to be successful (including the period of maintenance) was about 1,089 h. INTERPRETATION & CONCLUSION: This hospital-based study showed that the average duration of occlusion therapy to achieve stable isoacuity was 7.2 months with an average occlusion of 6-7 h/day. Compliance to therapy was the most important factor affecting the duration of therapy. With increasing emphasis on paediatric eye diseases, amblyopia is at last getting its due importance as a cause of treatable correctable paediatric visual impairment which can have lifelong repercussions, both in terms of individual disability and financial burden to the society if not treated in time. As the therapy is simple and effective if started early, mass awareness, visual screening, and counselling would go a long way in treating the patients, thus decreasing the prevalence of amblyopia in the country.

Amblyopia↗
PubMedDate not supplied

[Predictability of amblyopia in ametropic children. Apropos of 96 cases].

PURPOSE: The aim of this cross-sectional retrospective study was to analyze the predictability of amblyopia in children with myopic and hyperopic unilateral and bilateral ametropia. MATERIALS AND METHODS: One hundred and sixty two eyes of 96 children, (mean age: 8.6 years), were included in this work. Mean visual acuities and significant refractive errors were estimated for all the cases. The frequency of amblyopia and strabismus was studied in cases without amblyopia and in cases with medium and high grade amblyopia. RESULTS: Mean visual acuities were significantly higher in cases of bilateral myopia (p < 0.001) and hyperopia (p < 0.05) compared with unilateral ametropia. The frequency of myopic eyes (p < 0.01), eyes with high grade of myopia (p < 0.002) and anisomyopic eyes (p < 0.001) was significantly higher in cases of high amblyopia compared with cases without amblyopia. Strabismus (p < 0.05) were also significantly more frequent in cases of high amblyopia as well as in cases of myopic eyes (p < 0.01). Moreover, in the group of high amblyopia, 6 cases (6/7) had developed an intolerance for contact lenses. CONCLUSIONS: The risk of developing high grade amblyopia appeared significantly associated with unilateral medium and high level myopia. Strabismus and difficulties with good correction of anisometropia by contact lenses or spectacle appeared to be predisposing factors. This observation would suggest the indication of refractive surgery might be useful in these particular cases. To conclude, this study emphasizes the importance of early treatment of ametropia to reduce the incidence of amblyopia in children.

Amblyopia↗
PubMed2006

Amblyopia: diagnostic and therapeutic options.

PURPOSE: To provide an overview of the current state of knowledge of amblyopia and highlight recent advances in diagnosis and treatment. DESIGN: Review of literature and perspective. METHODS: MEDLINE search for amblyopia, with a review of all recent literature adding authors' personal perspectives on the findings. RESULTS: Increased awareness of amblyopia and better screening techniques are required to identify children who are at risk for amblyopia at a younger age. Randomized, controlled trials have established atropine penalization as a viable alternative to occlusion therapy, have suggested that less treatment may be better tolerated and as effective as more traditionally used dosages, and have found no compelling evidence that treatment is beneficial clinically for older (over age 10) children with amblyopia. CONCLUSION: Early detection and treatment of amblyopia can improve the chances for a successful visual outcome. Considering that the conditions that place a patient at risk for amblyopia can be identified, that amblyopia responds to treatment, and that well-tolerated treatments for the condition are now recognized, it is not unreasonable to imagine that, in the near future, severe amblyopia could be eliminated as a public health problem.

Adolescent↗
PubMed2004

Isoametropic amblyopia due to high hyperopia in children.

PURPOSE: To identify children with isoametropic amblyopia due to moderate to high hyperopia and evaluate associated findings and visual acuity outcome. METHODS: Charts from two university's pediatric ophthalmology clinics were reviewed retrospectively. Healthy children with > or = +4.5 D spherical equivalent who did not have anisometropia > or = 1.5 D were selected for data collection. The charts of qualifying children with bilateral amblyopia (visual acuity of 20/40 or less) were further analyzed. RESULTS: Identified were 418 children with the above set of criteria for hyperopia; 36 of these children had isoametropic amblyopia (bilateral amblyopia). This gives an estimated prevalence of isoametropic amblyopia of 8.6% in children with at least 4.5 D of hyperopia in one or both eyes. The children with isoametropic amblyopia presented at a later age (5 years, 1 month) than the overall group of hyperopes (3 years, 5 months). Strabismus was less prevalent in this group (64%) than in the entire population of children with high hyperopia (81%). These children's amblyopia responded well to treatment with glasses, and patching in 13 (36%) cases. Surgical intervention for residual strabismus was necessary in very few cases (2 of 36, 5.5%). CONCLUSION: Children with hyperopia > or = 4.5 D have an increased risk of amblyopia and strabismus that further threatens their future visual function. Isoametropic amblyopia is a real risk in these children. Based on these results, hyperopic correction should be prescribed for children with > or = 4.5 D of hyperopia even if no strabismus or fixation preference is detected, to reduce this risk. Screening programs should also be in place to identify these children at an early age.

Amblyopia↗
PubMed2006

Recurrence of amblyopia after occlusion therapy.

PURPOSE: To determine the stability of visual acuity (VA) after a standardized occlusion regimen in children with strabismic and/or anisometropic amblyopia. DESIGN: Retrospective, population-based, consecutive observational case series. PARTICIPANTS: Four hundred forty-nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy. METHODS: We performed a retrospective chart review of all patients treated by occlusion therapy for strabismic and/or anisometropic amblyopia at our institution over a 34-year period. Of the 1621 patients identified in our database, 449 met the eligibility criteria and were included in this study. Patients having at least a 2 logarithm of the minimum angle of resolution (logMAR)-level improvement in VA by optotypes or a change from unmaintained to maintained fixation preference during the course of occlusion therapy were included. A recurrence of amblyopia was defined as > or =2 logMAR levels of VA reduction or reversal of fixation preference within 1 year after a decrease or cessation of occlusion therapy. MAIN OUTCOME MEASURE: Recurrence of amblyopia after a decrease or cessation of occlusion therapy and its relationship with patient age and VA of the amblyopic eye at the time of decrease or cessation of occlusion therapy. RESULTS: Of 653 occlusion trials, 179 (27%) resulted in recurrence of amblyopia. The recurrence was found to be inversely correlated with patient age. There was no statistically significant association between the recurrence of amblyopia and VA of the amblyopic eye at the end of maximal occlusion therapy. CONCLUSIONS: There is a clinically important risk of amblyopia recurrence when occlusion therapy is decreased before the age of 10 years. The risk of recurrence is inversely correlated with age (P<0.0001).

Aging↗
PubMed2001

The association between nonstrabismic anisometropia, amblyopia, and subnormal binocularity.

PURPOSE: To determine if thresholds exist for the development of amblyopia and subnormal binocularity with various types of anisometropia and to compare these with existing guidelines for the treatment or observation of anisometropia. DESIGN: The records of all previously untreated patients evaluated for isolated refractive error during a 42-month period were reviewed to assess the association between anisometropia, amblyopia, and subnormal binocularity. PARTICIPANTS: Three hundred sixty-one (361) patients with anisometropia and 50 nonanisometropic control participants, examined over a 42-month period, with no history of treatment for refractive error, amblyopia, or other ocular pathologic characteristics were evaluated. METHODS: Uncorrected visual acuity in each eye, monofixation response, and degree of stereopsis were recorded for each patient. Patients with unequal or subnormal uncorrected visual acuity were retested with cycloplegic refraction. If the visual acuity was still abnormal, patients were retested while wearing spectacles. MAIN OUTCOME MEASURES: Degree and type of anisometropia were compared with incidence and severity of amblyopia and subnormal binocularity. RESULTS: Spherical myopic anisometropia (SMA) of more than 2 diopters (D) or spherical hypermetropic anisometropia (SHA) of more than 1 D results in a significant increase in the incidence of amblyopia and decrease in binocular function when compared with nonanisometropic patients (P = 0.05). Increasing levels of SMA and SHA beyond these thresholds result in increased incidence and severity of amblyopia. Cylindrical myopic anisometropia (CMA) or cylindrical hyperopic anisometropia (CHA) of more than 1.5 D results in a significant increase in amblyopia and a decrease in binocular function (P = 0.05). Levels of CMA and CHA more than 1.5 D result in an increased incidence and severity of amblyopia. CONCLUSIONS: This study supports existing guidelines for the treatment or observation of anisometropia and characterizes the association between the type and degree of anisometropia and the incidence and severity of amblyopia and subnormal binocularity.

Adolescent↗