eMedicine Specialties > Ophthalmology > Neurologic Disorders
Amblyopia: Treatment & Medication
Updated: Dec 31, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
- The clinician must first rule out an organic cause and treat any obstacle to vision (eg, cataract, occlusion of the eye from other etiologies).
- Remove cataracts in the first 2 months of life, and aphakic correction must occur quickly.
- Treatment of anisometropia and refractive errors must occur next.8,9,10,11
- The amblyopic eye must have the most accurate optical correction possible. This should occur prior to any occlusion therapy because vision may improve with spectacles alone.
- Full cycloplegic refraction should be given to patients with accommodative esotropia and amblyopia. In other patients, a prescription less than the full plus measurement that was refracted may be prescribed given that the decrease in plus is symmetric between the two eyes. Because accommodative amplitude is believed to be decreased in amblyopic eyes, one needs to be cautious about cutting back too much on the amount of plus. Refractive correction alone has been shown to improve amblyopia in up to 77% of patients in a nationwide trial.
- Patients with bilateral refractive amblyopia do well with spectacle correction alone, with most children aged 3-10 years achieving 20/25 or better within a year.12,13
- The next step is forcing the use of the amblyopic eye by occlusion therapy. Occlusion therapy has been the mainstay of treatment since the 18th century. The following are general guidelines for occlusion therapy:
- Patching may be full-time or part-time. Standard teaching has been that children need to be observed at intervals of 1 week per year of age, if undergoing full-time occlusion to avoid occlusion amblyopia in the sound eye. The Amblyopia Treatment Studies (ATS) have helped to provide new information on the effect of various amounts of patching.14,15
- Always consider lack of compliance in a child where visual acuity is not improving. Compliance is difficult to measure but is an important factor in determining the success of this therapy.
- In addition to adhesive patches, opaque contact lenses, occluders mounted on spectacles, and adhesive tape on glasses have been used.
- Establishing the fact that the vision of the better eye has been degraded sufficiently with the chosen therapy is important.
- The Amblyopia Treatment Studies have helped to define the role of full-time patching versus part-time patching in patients with amblyopia. The studies have demonstrated that, in patients aged 3-7 years with severe amblyopia (visual acuity between 20/100 and 20/400), full-time patching produced a similar effect to that of 6 hours of patching per day. In a separate study, 2 hours of daily patching produced an improvement in visual acuity similar to that of 6 hours of daily patching when treating moderate amblyopia (visual acuity better than 20/100) in children aged 3-7 years. In this study, patching was prescribed in combination with 1 hour of near visual activities.
- Data from the Amblyopia Treatment Studies are also available for older patients. For patients aged from 7 years to younger than 13 years, the Amblyopia Treatment Studies have suggested that prescribing 2-6 hours a day of patching can improve visual acuity even if the amblyopia has been previously treated. For patients aged from 13 years to younger than 18 years, prescribing 2-6 hours a day of patching might improve visual acuity when amblyopia has not been previously treated; however, this is likely to be of little benefit if amblyopia was previously treated with patching. Long-term results from these studies are still pending.16
- The Amblyopia Treatment Studies have also found that about one fourth of children with amblyopia who were successfully treated experience a recurrence within the first year after discontinuation of treatment. Data from these studies suggest that patients treated with 6 or more hours a day of patching have a greater risk of recurrence when patching is stopped abruptly rather than when it is reduced to 2 hours a day prior to cessation of patching. Randomized studies have still yet to be performed.17
- Penalization therapy
- In the past, penalization therapy was reserved for children who would not wear a patch or in whom compliance was an issue. The Amblyopia Treatment Studies, however, have demonstrated that atropine penalization in patients with moderate amblyopia (defined by the study as visual acuity better than 20/100) is as effective as patching. The Amblyopia Treatment Studies were performed in children aged 3-7 years.18,19,20,21
- The Amblyopia Treatment Studies have also demonstrated that weekend use of atropine provided an improvement in visual acuity similar to that of daily use of atropine when treating moderate amblyopia in children aged 3-7 years.
- Atropine drops or ointment is instilled in the nonamblyopic eye. This therapy is sometimes used in conjunction with patching or occlusion of the glasses (eg, adhesive tape, nail polish) by individual practitioners. In the Amblyopia Treatment Studies that evaluated patching versus atropine penalization, atropine penalization and patching were used in conjunction with 1 hour of near visual activities.
- This technique may also be used for maintenance therapy, which is useful, especially in patients with mild amblyopia.
- Other options include optical blurring through contact lenses or elevated bifocal segments.22
- The endpoint of therapy is spontaneous alternation of fixation or equal visual acuity in both eyes.23
- When visual acuity is stable, patching may be decreased slowly, depending on the child's tendency for the amblyopia to recur.
- Because amblyopia recurs in a large number of patients (see Prognosis), maintenance therapy or tapering of therapy should be strongly considered. This tapering is controversial, so individual physicians vary in their approaches.
- Treatment of strabismus generally occurs last. The endpoint of strabismic amblyopia is freely alternating fixation with equal vision. Surgery generally is performed after this endpoint has been reached.
Surgical Care
Surgical therapy for strabismus generally should occur after amblyopia is reversed. Disadvantages to surgical therapy prior to correction of amblyopia include difficulty in telling if amblyopia is present because there is no longer a strabismus to assess fixation preference and higher potential to being lost to follow-up, as the child cosmetically looks better. The improved cosmesis gives the parents a false sense of security about the vision improving.
Activity
Close supervision during occlusion therapy is necessary to make sure children do not peek. Various methods of preventing children from removing patches have been considered, from a reward system for older children to arm splints and mittens for infants.
Medication
Pharmacologic treatment with levodopa has been investigated and has showed transient improvement of vision in amblyopic eyes. However, the exact role of such pharmacologic agents has not been determined. Levodopa currently is not being used clinically.
Atropine penalization (with either ointment or drops) is an alternative method of blurring vision in the sound eye of patients who refuse patching. It may be applied once a day to patients in the preferred eye only.
Cycloplegics
These agents are used to blur vision in one eye to treat amblyopia in the contralateral eye.
Atropine sulfate 0.5 - 2.0% (Isopto, Atropair, Atropisol)
A topically applied muscarinic antagonist, which blocks the action of acetylcholine. This results in paralysis of the iris sphincter and resultant pupillary dilation. Paralysis of the ciliary muscles also occurs, which inhibits accommodation and relieves pain in iridocyclitis. The medication is dispensed in a topical formulation, either an ointment or a solution.
Adult
1 gtt in the fornix in affected eye 1-3 times qd, then taper as necessary
Pediatric
1 gtt in the fornix in affected eye qd
Coadministration with other anticholinergics have additive effects; pharmacologic effects of atenolol and digoxin may increase with atropine; antipsychotic effects of phenothiazines may decrease with this medication; tricyclic antidepressants with anticholinergic activity may increase effects of atropine
Documented hypersensitivity; thyrotoxicosis; narrow-angle glaucoma; tachycardia; infants; albino patients; Down syndrome
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Adverse effects include flushing, fever, tachycardia, urinary retention, and delirium; adverse effects are usually dose-related from systemic absorption; local irritation may occur; emphasize that the medication should be used topically only and kept out of reach of children; practice proper hand washing after administration; caution in coronary heart disease, congestive heart failure, cardiac arrhythmias, hypertension, peritonitis, ulcerative colitis, hepatic disease, and hiatal hernia with reflux esophagitis; in prostatic hypertrophy, prostatism can have dysuria and may require catheterization
More on Amblyopia |
| Overview: Amblyopia |
| Differential Diagnoses & Workup: Amblyopia |
 Treatment & Medication: Amblyopia |
| Follow-up: Amblyopia |
| References |
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References
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Kushner, BJ. Amblyopia. In: Nelson LB, ed. Harley's Pediatric Ophthalmology. 1998:125-39.
von Noorden GK. Binocular Vision and Ocular Motility: Theory and Management. 1996;216-54.
Lempert P. Retinal area and optic disc rim area in amblyopic, fellow, and normal hyperopic eyes: a hypothesis for decreased acuity in amblyopia. Ophthalmology. Dec 2008;115(12):2259-61. [Medline].
Daw NW. Critical periods and amblyopia. Arch Ophthalmol. Apr 1998;116(4):502-5. [Medline].
Kirschen DG. Understanding Sensory Evaluation. In: Rosenbaum AL, Santiago AP, eds. Clinical Strabismus Management: Principles and Practice. 1999: 22-35.
Lin LK, Uzcategui N, Chang EL. Effect of surgical correction of congenital ptosis on amblyopia. Ophthal Plast Reconstr Surg. Nov-Dec 2008;24(6):434-6. [Medline].
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Flynn JT, Woodruff G, Thompson JR, et al. The therapy of amblyopia: an analysis comparing the results of amblyopia therapy utilizing two pooled data sets. Trans Am Ophthalmol Soc. 1999;97:373-90; discussion 390-5. [Medline].
Flynn JT. 17th annual Frank Costenbader Lecture. Amblyopia revisited. J Pediatr Ophthalmol Strabismus. Jul-Aug 1991;28(4):183-201. [Medline].
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Holmes JM, Kraker RT, Beck RW, et al. A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children. Ophthalmology. Nov 2003;110(11):2075-87. [Medline].
Repka MX, Beck RW, Holmes JM, et al. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol. 2003;121:603-11. [Medline].
Scheiman MM, Hertle RW, Beck RW, et al. Randomized trial of treatment of amblyopia in children aged 7 to 17 years. Arch Ophthalmol. Apr 2005;123(4):437-47. [Medline].
Holmes JM, Beck RW, Kraker RT, et al. Risk of amblyopia recurrence after cessation of treatment. J AAPOS. 2004;8:420-8. [Medline].
Pediatric Eye Disease Investigator Group. A randomized trial of atropine vs. patching for treatment of moderate amblyopia in children. Arch Ophthalmol. 2002;120:268-278. [Medline].
Repka MX, Wallace DK, Beck RW, et al. Two-year follow-up of a 6-month randomized trial of atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol. 2005;123:149-157. [Medline]. [Full Text].
Repka MX, Cotter SA, Beck RW, et al. A randomized trial of atropine regimens for treatment of moderate amblyopia in children. Ophthalmology. 2004;111:2076-85. [Medline].
Scheiman MM, Hertle RW, Kraker RT, et al. Patching vs atropine to treat amblyopia in children aged 7 to 12 years: a randomized trial. Arch Ophthalmol. Dec 2008;126(12):1634-42. [Medline].
Collins RS, McChesney ME, McCluer CA, et al. Occlusion properties of prosthetic contact lenses for the treatment of amblyopia. J AAPOS. Dec 2008;12(6):565-8. [Medline].
Repka MX. How much amblyopia treatment is enough?. Arch Ophthalmol. Jul 2008;126(7):990-1. [Medline].
Levartovsky S, Oliver M, Gottesman N, Shimshoni M. Factors affecting long term results of successfully treated amblyopia: initial visual acuity and type of amblyopia. Br J Ophthalmol. Mar 1995;79(3):225-8. [Medline].
Wallace DK, 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. Jun 2006;113(6):904-12. [Medline].
Further Reading
Keywords
amblyopia, lazy eye, functional amblyopia, organic amblyopia, decreased vision, poor visual acuity, vision loss, monocular vision loss, blindness in one eye, strabismus, strabismic anisometropia, anisometropia, amblyopia treatment studies, ATS, refractive error, occlusion therapy, patching
