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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 4  |  Issue : 2  |  Page : 71-74

Occlusion therapy in older children with amblyopia


Department of Pediatric Ophthalmology, Sankara Eye Hospital, Shimoga, Karnataka, India

Date of Submission20-Apr-2015
Date of Acceptance27-Nov-2015
Date of Web Publication9-Jun-2016

Correspondence Address:
V Kavitha
Sankara Eye Hospital, Thirthahalli Road, Harakere, Shimoga - 577 202, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2320-3897.183657

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  Abstract 

Background: Occlusion therapy is effective in older children with amblyopia. Objective: To evaluate and compare visual outcomes in older children aged between 9 and 18 years with unilateral refractive amblyopia after treatment with patching and/or optical correction. Settings and Design: Prospective randomized controlled study. Materials and Methods: Sixty children (9-18 years) with unilateral refractive amblyopia (anisometropic/meridional) with best-corrected visual acuity (BCVA) ≤6/12 (0.3 logMAR) in the worse eye were 1:1 randomized into nonocclusion and occlusion group. Both treatment groups underwent 4 weeks refractive adaptation period (RAP) and three follow-up visits at 6 weeks interval. After RAP, the better eye in the occlusion group was patched for 6 h daily, while the nonocclusion group children continued to wear spectacles for 18 weeks. BCVA (logMAR) at each visit was compared with the baseline reading. Statistical Analysis Used: Descriptive and inferential statistical analyses were used. Student's t-test and Chi-square/Fisher exact test was used to calculate the P value. Results: There was a significant improvement in BCVA from baseline to 18 weeks after RAP within both treatment groups (P < 0.001) and significant higher proportion of children in occlusion group showed three lines of improvement compared with nonocclusion group (P = 0.011). Improvement in BCVA from baseline to 18 weeks was noted irrespective of the severity of amblyopia and age of the participants more so in occlusion group. Conclusion: Occlusion therapy is an effective and better treatment than only spectacle correction in children aged between 9 and18 years, with unilateral refractive amblyopia.

Keywords: Effective, occlusion therapy, older children, refractive amblyopia, unilateral


How to cite this article:
Kavitha V, Chaitra S, Heralgi MM. Occlusion therapy in older children with amblyopia. J Clin Ophthalmol Res 2016;4:71-4

How to cite this URL:
Kavitha V, Chaitra S, Heralgi MM. Occlusion therapy in older children with amblyopia. J Clin Ophthalmol Res [serial online] 2016 [cited 2020 Sep 20];4:71-4. Available from: http://www.jcor.in/text.asp?2016/4/2/71/183657

Amblyopia is reduced visual acuity (VA) caused by abnormal binocular interaction or visual deprivation during a sensitive period of visual development in early childhood. [1] It has been estimated to affect 2-5% of the population, [2] and the incidence in India is between 1.1 and 12.3%. [3] The causes are strabismus (about 50%), anisometropia (about 17%) or strabismus and anisometropia (about 30%), and visual deprivation (about 3%). [4] Amblyopic patients have poor spatial acuity, low contrast sensitivity, and reduced sensitivity to motion. [5]

In 1979, Von Noorden and Crawford suggested <8 years as an ideal age for amblyopia treatment; >8 years was considered as the end of the critical period for visual development in children. [6] Various published literature supported age to be a common crucial factor for amblyopia treatment. [7],[8],[9],[10],[11],[12] However, in 2007, the American Academy of Ophthalmology recommended that amblyopia treatment should be given to all children, regardless of their age. [13] Treatment of amblyopia includes surgery, refractive error correction (optical), force use of the amblyopic eye by limiting use of the better eye (penalization of the better eye [defocusing the better eye using atropine/homatropine/cyclopentolate or by altering the power of spectacle lens to cause decreased vision in the better eye] or occlusion of the better eye [patching]), [4],[14] and pharmacological therapy (levodopa, carbidopa, and citicoline). [15],[16],[17] Cambridge stimulator and pleoptics were used earlier in the treatment of amblyopia. However, occlusion of the nonamblyopic eye is still the mainstay of treatment. [1]

A previously published literature reported that daily patching of a better eye along with optical correction significantly improved amblyopia in children aged 3-7 years compared to optical correction using spectacles only. [18] PEDIG in amblyopia treatment study 3 evaluated the effectiveness of optical correction alone versus 2-6 h/day of patching combined with near visual activities plus atropine sulfate in older children aged 7-17 years. [19] However, there is a paucity of Indian literature regarding the adjuvant use of patching with optical correction for amblyopia treatment in older age group.

Hence, the present study was planned with an objective to evaluate and compare visual outcomes in children (aged 9-18 years) with amblyopia after treatment with patching and/or optical correction.


  Materials and Methods Top


This was a prospective randomized control study of 60 amblyopic children attending the outpatient department between June 2013 and March 2014. Informed consent was obtained from parents of all 60 children. Inclusion criteria included males and females of age 9-18 years with unilateral refractive amblyopia (anisometropic/meridional) and best-corrected VA (BCVA) ≤6/12 (0.3 logMAR) in the worse eye. Children with visual deprivation, strabismus, bilateral refractive amblyopia, history of previous amblyopia treatment within 1 year of enrollment, or who underwent prior intraocular/extraocular surgery with known skin reaction/s to patch or bandage adhesive were excluded from the study. The study adhered to all the principles mentioned in the Declaration of Helsinki 2000.

All patients underwent a detailed ophthalmologic examination at baseline. Following parameters/visual outcomes were assessed-uncorrected VA and BCVA (logMAR chart for distance and Snellen's chart for near), ocular alignment and fixation by cover and alternate cover test, slit lamp examination, fundus examination (with indirect ophthalmoscopy using + 20 D condensing lens or slit lamp biomicroscopy using + 90 diopter (D) lens), cycloplegic refraction (1% cyclopentolate eye drops) with streak retinoscope, and subjective correction (3 days later). All children who fulfilled the inclusion and exclusion criteria were included in the study and spectacles were prescribed. A 4 weeks gap of refractive adaptation period (RAP) [20] was allowed for each child to wear glasses constantly. Each child was then assigned with equal probability by simple random allocation using randomization table to either optical correction only (nonocclusion group) optical correction plus patching (occlusion group). Following the RAP, patching of the better eye was done 6 h daily in occlusion group and were advised to perform near activities such as reading, writing (homework), drawing, computer work, and playing mobile games. [21],[22] Children in nonocclusion group continued to wear spectacles. Both the treatment groups underwent three follow-up visits at a 6-week interval. Parents of occlusion group were thoroughly counseled to daily record the number of hours of the patch which helped the physician to record occlusion compliance rate (total number of hours patched in a month/total number of hours of patch prescribed per month × 100%). [2] The compliance was classified as good if % compliance rate >90%, fair if 70-90%, and poor if <70%. Children were followed thrice at 6-week interval, and BCVA was recorded at each visit using the logMAR chart. The BCVA recording at follow-up visits was compared with the baseline reading.

Statistical analyses

Data were analyzed using SAS 9.2, SPSS 15.0, Stata 10.1, MedCalc 9.0.1, Systat 12.0, and R environment version 2.11.1. (IBM) Descriptive and inferential statistical analyses were carried out. Student's t-test (two-tailed, independent) and Chi-square/Fisher exact test was used to calculate the P value. A significance level of 5% was used and the power was set to 90%.


  Results Top


Out of 60 (males: 34; females: 26) children, 39 were aged 10-13 years and 21 children were aged 14-17 years. The higher proportion of children in both treatment groups had amblyopia in the right eye with severe amblyopia in 30% of children in nonocclusion group and 46.6% in occlusion group. The demographic and all baseline characteristics were comparable between the treatment groups [Table 1]. Fifty-three percent of the children had fair, 33% had good, and 13% had poor occlusion compliance rate.
Table 1: Children characteristics at baseline

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There was a significant improvement in BCVA from baseline to 18 weeks after RAP within both treatment groups (P < 0.001; [Table 2]) and significant higher proportion of children in occlusion group showed 3 lines of improvement compared to nonocclusion group (P = 0.011) [Table 3].

There was an improvement in BCVA from baseline to 18 weeks in both these groups irrespective of the severity of amblyopia and age of the participants and more so in occlusion group [Table 4].
Table 2: Best-corrected visual acuity in amblyopic eye: A comparative evaluation between two groups

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Table 3: Improvement of best-corrected visual acuity

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Table 4: Improvement in best-corrected visual acuity in amblyopic eye with respect to severity and age

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  Discussion Top


The rationale for treatment of unilateral amblyopia is to optimize visual function and binocular vision, to maximize employment opportunities and to try to provide a useful "spare eye" in the event of trauma or pathology in the normal eye.

There have been controversial debates on the concept that success of amblyopia treatment depends on patient's age at initiation of the treatment. [1],[10],[23] Various studies have favored amblyopia treatment at age <6-7 years [9],[10],[12] but few studies have reported better outcomes in older children. [7],[18],[19],[24],[25] Our study results are also in concordance to the published literature where visual outcomes were independent of patient's age; suggesting that amblyopia can be treated successfully beyond the age that is considered to be the critical period for the visual development.

In 2010, Carlton and Czoski-Murray. [20] reported vision improvement 4-12 weeks after optical treatment and within 3-6 months following occlusion. [26] Consistent to the published literature, 4-week RAP was followed by 18-week occlusion.

The study reported 3 line of significant improvement from baseline to 18 weeks occlusion period after RAP in the occlusion group compared to the nonocclusion group;

VA improvement by ≥1 line, in occlusion group, was seen in 43.3% children with mild to moderate amblyopia and 36.6% with severe amblyopia as compared to 40% and 20%, respectively in nonocclusion group. However, 3 lines of improvement were seen only in the occlusion group.

BCVA improvement ≥1 line was seen in both the age groups, 10-13 years and 14-17 years and in both the occlusion and nonocclusion groups (15 and 9 children in occlusion group; 12 and 6 children in nonocclusion group), respectively. However, 3 lines of improvement were seen in only in occlusion group and in both the age groups.

This implies the importance of occlusion therapy in visual improvement in amblyopic eyes. The reason for better visual outcomes in the occlusion group may be due to the performance of near activities as suggested in the previous literature [18] and/or due to high (86% fair to good) occlusion compliance rate as compliance to occlusion is one of the vital factors to achieve better visual outcomes. [7],[25],[27]


  Conclusion Top


Occlusion therapy is an effective and better treatment than only spectacle correction in children, aged 9-18 years, with unilateral refractive amblyopia.

Acknowledgment

Management - Sankara Eye Hospital, Praveen K, Shylaja, Milind M, Mrs. Geetha, Shivaswamy, Mr. K. P. Suresh (Statistician), Dr. Somashekhar S. P. Sailaja K, Geetha H, Shivaswamy H. M.

Financial support and sponsorship


Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Von Noorden GK, Campos E. Binocular Vision and Ocular Motility. 6 th ed. St. Louis, MO: Mosby; 2002.  Back to cited text no. 1
    
2.
Santos MA, Valbuena MN, Monzon-Pajarillo AK. Visual outcomes of amblyopia therapy. Philipp J Ophthalmol 2012;37:33-8.  Back to cited text no. 2
    
3.
Menon V, Chaudhuri Z, Saxena R, Gill K, Sachdev MM. Profile of amblyopia in a hospital referral practice. Indian J Ophthalmol 2005;53:227-34.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
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De Zárate BR, Tejedor J. Current concepts in the management of amblyopia. Clin Ophthalmol 2007;1:403-14.  Back to cited text no. 4
    
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Astle AT, McGraw PV, Webb BS. Can human amblyopia be treated in adulthood? Strabismus 2011;19:99-109.  Back to cited text no. 5
    
6.
Von Noorden GK, Crawford ML. The sensitive period. Trans Ophthalmol Soc U K 1979;99:442-6.  Back to cited text no. 6
    
7.
Oliver M, Neumann R, Chaimovitch Y, Gotesman N, Shimshoni M. Compliance and results of treatment for amblyopia in children more than 8 years old. Am J Ophthalmol 1986;102:340-5.  Back to cited text no. 7
    
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Quah BL, Tay MT, Chew SJ, Lee LK. A study of amblyopia in 18-19 year old males. Singapore Med J 1991;32:126-9.  Back to cited text no. 8
    
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Rutstein RP, Fuhr PS. Efficacy and stability of amblyopia therapy. Optom Vis Sci 1992;69:747-54.  Back to cited text no. 9
    
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Epelbaum M, Milleret C, Buisseret P, Dufier JL. The sensitive period for strabismic amblyopia in humans. Ophthalmology 1993;100:323-7.  Back to cited text no. 10
    
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Woodruff G, Hiscox F, Thompson JR, Smith LK. Factors affecting the outcome of children treated for amblyopia. Eye (Lond) 1994;8(Pt 6):627-31.  Back to cited text no. 11
    
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Flynn JT, Schiffman J, Feuer W, Corona A. The therapy of amblyopia: An analysis of the results of amblyopia therapy utilizing the pooled data of published studies. Trans Am Ophthalmol Soc 1998;96:431-50.  Back to cited text no. 12
    
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Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern Guidelines. Amblyopia. San Francisco: American Academy of Ophthalmology; 2007.  Back to cited text no. 13
    
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Amblyopia. American Academy of Ophthalmology. Pediatric Ophthalmology and Strabismus, 2014-2015. Italy. p. 37-9.  Back to cited text no. 14
    
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Repka MX, Ray JM. The efficacy of optical and pharmacological penalization. Ophthalmology 1993;100:769-74.  Back to cited text no. 15
    
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Foley-Nolan A, McCann A, O′Keefe M. Atropine penalisation versus occlusion as the primary treatment for amblyopia. Br J Ophthalmol 1997;81:54-7.  Back to cited text no. 16
    
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Pediatric Eye Disease Investigator Group. A randomized trial of atropine vs. patching for treatment of moderate amblyopia in children. Arch Ophthalmol 2002;120:268-78.  Back to cited text no. 17
    
18.
Wallace DK; Pediatric Eye Disease Investigator Group, Edwards AR, Cotter SA, Beck RW, Arnold RW, Astle WF, et al. A randomized trial to evaluate 2 hours of daily patching for strabismic and anisometropic amblyopia in children. Ophthalmology 2006;113:904-12.  Back to cited text no. 18
    
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Pediatric Eye Disease Investigator Group. Randomized trial of treatment of amblyopia in children aged 7 to 17 years. Arch Ophthalmol 2005;123:437-47.  Back to cited text no. 19
    
20.
Carlton J, Czoski-Murray C. The value of screening for amblyopia revisited. In: Pediatric Ophthalmology, Neuro-Ophthalmology, Genetics: Strabismus - New Concepts in Pathophysiology, Diagnosis, and Treatment. Berlin, Heidelberg: Springer; 2010. p. 95-111.  Back to cited text no. 20
    
21.
Scheiman MM, Hertle RW, Beck RW, Edwards AR, Birch E, Cotter SA, et al. Randomized trial of treatment of amblyopia in children aged 7 to 17 years. Arch Ophthalmol 2005;123:437-47.  Back to cited text no. 21
    
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Lee YR, Lee JY. Part-time occlusion therapy for anisometropic amblyopia detected in children eight years of age and older. Korean J Ophthalmol 2006;20:171-6.  Back to cited text no. 22
    
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Park KH, Hwang JM, Ahn JK. Efficacy of amblyopia therapy initiated after 9 years of age. Eye (Lond) 2004;18:571-4.  Back to cited text no. 23
    
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Hedgpeth EM Jr, Sullivan M. Anisometropic amblyopia and its treatment. South Med J 1977;70:1059-60.  Back to cited text no. 24
    
25.
Mintz-Hittner HA, Fernandez KM. Successful amblyopia therapy initiated after age 7 years: Compliance cures. Arch Ophthalmol 2000;118:1535-41.  Back to cited text no. 25
    
26.
Cleary M. Efficacy of occlusion for strabismic amblyopia: Can an optimal duration be identified? Br J Ophthalmol 2000;84:572-8.  Back to cited text no. 26
    
27.
Smith LK, Thompson JR, Woodruff G, Hiscox F. Factors affecting treatment compliance in amblyopia. J Pediatr Ophthalmol Strabismus 1995;32:98-101.  Back to cited text no. 27
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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