|Year : 2007 | Volume
| Issue : 6 | Page : 469-470
Is age relevant for the success of treatment of anisometropic amblyopia?
Neela A Patwardhan
Sion Eye Clinic and Microsurgery Centre, Mumbai, India
|Date of Submission||15-Mar-2006|
|Date of Acceptance||18-Feb-2007|
Neela A Patwardhan
14/138, Poornima, Indulal Bhuva Marg, Wadala, Mumbai - 400 031
Source of Support: None, Conflict of Interest: None
A prospective cohort study of 200 anisometropic amblyopes was conducted. The patients were classified into two groups. Group A: Patients less than 12 years of age. This consisted of 144 (72%) patients, the average age being 7.77 years (±2.34, range 1 to 12). Group B: Patients more than 12 years of age. This comprised 56 (28%) patients, the average age being 19.8 years (±5.47, range 12 to 30). Criterion for success was defined as best corrected visual acuity of 20/40 (0.5 logMAR equivalent) or better. The Chi-square test was used to compare baseline characteristics and success rates. There were no significant differences in the baseline characteristics between the two groups ( P =0.07). The treatment was successful in 108 (75%) in Group A and in 34 (60.7%) in Group B ( P = 0.07). There was no statistically significant change in the success rate of treatment of anisometropic amblyopia, even beyond 12 years of age.
Keywords: Age at presentation, anisometropic amblyopia
|How to cite this article:|
Patwardhan NA. Is age relevant for the success of treatment of anisometropic amblyopia?. Indian J Ophthalmol 2007;55:469-70
|How to cite this URL:|
Patwardhan NA. Is age relevant for the success of treatment of anisometropic amblyopia?. Indian J Ophthalmol [serial online] 2007 [cited 2019 Nov 19];55:469-70. Available from: http://www.ijo.in/text.asp?2007/55/6/469/36488
There has been a general belief that amblyopia cannot be treated beyond a certain age, the age varying from six to 12 years. Although awareness of treating amblyopia at older ages has increased there is uncertainty about the age up to which a patient can be treated.  The aim of the study was to determine the efficacy of treatment of anisometropic amblyopia in patients more than 12 years of age i.e., beyond the pediatric age group and to compare their success rate with those in patients less than 12 years of age.
| Materials and Methods|| |
Patients having anisometropic amblyopia were enrolled in a prospective cohort study, conducted in an urban private-practice setup, from August 1992 to August 2000. The patients, after a detailed history-taking underwent a meticulous examination as follows: assessment of visual acuity, pupillary reflexes, orthoptic check-up for fixation, alignment and motility, an external and a fundoscopic examination. The only criterion for inclusion was pure anisometropic amblyopia. Patients having any other associated ocular, systemic pathology or congenital anomaly, were excluded. Baseline characteristics recorded were gender, initial visual acuity, interocular visual acuity difference and the type of refractive error. A standard treatment protocol, as follows, was used for patient management:
a) All patients underwent a cycloplegic refraction. Children under six and hypermetropes up to twelve years of age were atropinised. Cyclopentolate hydrochloride 1% was used for cycloplegia in the remaining patients.
b) The best refractive error correction, closest to the cycloplegic refraction, accepted by the patient was prescribed. Refractions were repeated at every follow-up and the prescriptions changed until the full cycloplegic correction was accepted.
c) The patients, after the initial refractive adaptation period, which varied from one month to three months, were put on effective occlusion, defined as part-time occlusion of the dominant eye for three hours, with active use of the amblyopic eye. Occlusion of the dominant eye was done with a ground glass in the spectacle (or an initial opticlude patch, till they became cooperative), for a continuous period of three hours. During this period of occlusion, active use of the amblyopic eye was ensured by giving the patients near visual tasks. They were asked to trace alphabet or picture charts and encouraged to do their study/office work during the time of occlusion. Compliance was ensured by asking the patients to submit these charts as proof of homework done, at the time of the next follow-up. Follow-up was done at monthly intervals. The refractions were repeated and the best corrected visual acuity (BCVA) was recorded. Once the full cycloplegic refraction was accepted, the follow-up was done three-monthly.
Two hundred consecutive patients who completed the treatment were analyzed. The patients were classified according to their age into two groups: Group A: Patients less than 12 years of age. Group B: Patients more than 12 years of age.
The treatment was considered complete when it could be classified as successful or unsuccessful. Criterion for success was defined as the BCVA of Snellen's visual acuity of 20/40 (0.5 logMAR equivalent) or more. The treatment was considered as unsuccessful when the BCVA was less than Snellen's 20/40 (0.5 logMAR equivalent), with no further improvement after three consecutive follow-ups at three-monthly intervals. Statistical analysis was done using EpiInfo statistical program (Version 6, World Health Organization, Geneva). The Chi-square test was used to compare the baseline characteristics and the success rates. A P value of <0.05 was considered significant.
| Results|| |
Group A consisted of 144 (72%) patients, the average age being 7.77 years (±2.34, range 1 to 12) and the median being eight. Group B comprised 56 (28%) patients, the average age being 19.8 years (±5.47, range 12 to 30) and the median being 20. There were 98 males and 102 females. Initial visual acuity ranged from finger counting to 20/30 in both groups. Interocular visual acuity differences ranged from less than two lines to more than four lines in both groups. There were 56 (28%) myopes, 104 (52%) hypermetropes and 40 (20%) patients with mixed astigmatism. There were no significant differences in the baseline characteristics between the two groups ( P =0.07). Follow-ups ranged from nine months to 24 months, with an average of 15 months, the rate of improvement and the duration of treatment being similar in both groups. The treatment was successful in 108 (75%) in Group A and in 34 (60.7%) in Group B. There was no statistically significant difference ( P =0.07) between the two groups.
| Discussion|| |
The study shows that patients of anisometropic amblyopia responded to treatment irrespective of age. As far back as in 1982, Sen  had suggested that every effort should be made to treat patients even after 12 years of age. Hence, in this study the patients were classified into two groups namely, those more than and less than 12 years of age. Previous amblyopia studies ,, which concluded that the success rate did not vary with the age of starting treatment were conducted in patients in a smaller age group, the mean age being 4.58 to 5.42 years. Success of amblyopia treatment in older children up to 15 years of age, with fulltime occlusion is reported.  All patients in this study have been treated with part-time occlusion with equivalent success. Improvement of two or more lines with part-time occlusion is reported in 27% of patients from 10 to less than 18 years of age.  This study also differs in having a large part (28%) of the sample size, with the highest number of patients (56), in an older age group varying from 12 to 30, with a median of 20 years. A literature survey showed no documentation of a comparison of success rates between patients of anisometropic amblyopia, presenting in the pediatric group (before 12) and in the older, adult group (after 12 years of age). The findings of this study suggest that there may be no cut-off age beyond which a patient of anisometropic amblyopia will not respond to treatment.
The limitations of our study were as follows: a) "Compliance" was not monitored. b) Failures of earlier treatment taken elsewhere, were not weeded out. If such patients were considered as an exclusion criterion, the success rate would have been higher. Despite these limitations, a success rate of 60.7% was achieved in Group B- Pubmed search revealed no other documented proof of successful treatment in the largest number (56) of older and adult patients.
These findings are significant, as these 60.7% of older patients who can be successfully treated, may not even get enrolled for treatment due to long-standing false beliefs. It is important that ophthalmologists classify their amblyopic patients and treat patients of anisometropic amblyopia irrespective of age at presentation. The primary health workers, orthoptists, family physicians and pediatricians should also be made aware that the age of the patient need not be a bar for the treatment of anisometropic amblyopia.
In conclusion, there is no statistically significant change in the success rate of treatment of anisometropic amblyopia, even in patients older than 12 years of age.
| References|| |
Pediatric Eye Disease Investigator Group. A prospective, pilot study of treatment of amblyopia in children 10 to <18 years old. Am J Ophthalmol
Sen DK. Results of treatment of anisometropic amblyopia without strabismus. Br J Ophthalmol
Hiscox F, Strong N, Thompson JR, Minshull C, Woodruff G. Occlusion for amblyopia: A comprehensive survey of outcome. Eye
Kutschke PJ, Scott WE, Keech RV. Anisometropic amblyopia. Ophthalmology
Cobb CJ, Russell K, Cox A, Mac Ewen CJ. Factors influencing visual outcome in anisometropic amblyopia. Br J Ophthalmol
Mohan K, Saroha V, Sharma A. Successful occlusion therapy for amblyopia in 11 to 15-year-old children. J Pediatr Ophthalmol Strabismus
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