Interventions for strabismic amblyopia. 2011

Kate Taylor, and Sue Elliott
Department of Ophthalmology, Royal Victoria Infirmary, Claremont Wing, Queen Victoria Road, Newcastle upon Tyne, UK, NE1 4LP.

BACKGROUND Amblyopia is reduced visual acuity in one or both eyes in the absence of any demonstrable abnormality of the visual pathway. It is not immediately resolved by the correction of refractive error. Strabismus develops in approximately 5% to 8% of the general population. The aim of treatment for amblyopia is to obtain the best possible level of vision in the amblyopic eye. Different treatment options were examined within the review. OBJECTIVE By reviewing the available evidence we wanted to establish the most effective treatment for strabismic amblyopia. In particular this review aimed to examine the impact of conventional occlusion therapy for strabismic amblyopia and to analyse the role of partial occlusion and optical penalisation for strabismic amblyopia. METHODS We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 6), MEDLINE (January 1950 to June 2011), EMBASE (January 1980 to June 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 1 June 2011. METHODS We included randomised controlled trials (RCTs) for the treatment of strabismic amblyopia including participants of any age. METHODS Two authors working independently extracted and entered data into Review Manager 5 and then independently checked the data for errors. RESULTS We included three RCTs in this review. The studies reported mean logMAR visual acuity achieved. Mean difference in visual acuity was calculated. When comparing conventional part-time occlusion (with any necessary glasses), PEDIG 2006 reported that this treatment was more beneficial than glasses alone for strabismic amblyopia; the mean difference between groups was -0.18 LogMAR (statistically significant 95% confidence interval (CI) -0.32 to -0.04). Supplementing occlusion therapy with near activities may produce a better visual outcome compared to non-near activities after four weeks of treatment (PEDIG 2005). The results of the pilot study showed mean difference between groups was -0.17 LogMAR (95% CI -0.53 to 0.19). Results from a larger RCT (PEDIG 2008) are now available, showing that supplementing occlusion therapy with near activities may produce a better visual outcome after eight weeks of treatment; the mean difference between groups was -0.02 LogMAR (95% CI -0.10 to 0.06). CONCLUSIONS Occlusion, whilst wearing necessary refractive correction, appears to be more effective than refractive correction alone in the treatment of strabismic amblyopia. The benefit of combining near activities with occlusion is unproven. No RCTs were found that assessed the role of either partial occlusion or optical penalisation to refractive correction for strabismic amblyopia.

UI MeSH Term Description Entries
D002648 Child A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL. Children
D002675 Child, Preschool A child between the ages of 2 and 5. Children, Preschool,Preschool Child,Preschool Children
D005139 Eyeglasses A pair of ophthalmic lenses in a frame or mounting which is supported by the nose and ears. The purpose is to aid or improve vision. It does not include goggles or nonprescription sun glasses for which EYE PROTECTIVE DEVICES is available. Glasses,Spectacles,Sun Glasses, Prescription,Glasses, Prescription Sun,Prescription Sun Glasses
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000550 Amblyopia A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications. Anisometropic Amblyopia,Lazy Eye,Amblyopia, Developmental,Amblyopia, Stimulus Deprivation-Induced,Amblyopia, Suppression,Stimulus Deprivation-Induced Amblyopia,Amblyopia, Anisometropic,Amblyopia, Stimulus Deprivation Induced,Amblyopias,Amblyopias, Anisometropic,Amblyopias, Developmental,Amblyopias, Stimulus Deprivation-Induced,Amblyopias, Suppression,Anisometropic Amblyopias,Deprivation-Induced Amblyopia, Stimulus,Deprivation-Induced Amblyopias, Stimulus,Developmental Amblyopia,Developmental Amblyopias,Eye, Lazy,Eyes, Lazy,Lazy Eyes,Stimulus Deprivation Induced Amblyopia,Stimulus Deprivation-Induced Amblyopias,Suppression Amblyopia,Suppression Amblyopias
D012683 Sensory Deprivation The absence or restriction of the usual external sensory stimuli to which the individual responds. Deprivation, Sensory,Deprivations, Sensory,Sensory Deprivations
D013285 Strabismus Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641) Concomitant Strabismus,Dissociated Horizontal Deviation,Dissociated Vertical Deviation,Heterophoria,Heterotropias,Hypertropia,Non-Concomitant Strabismus,Nonconcomitant Strabismus,Phorias,Squint,Strabismus, Comitant,Strabismus, Noncomitant,Convergent Comitant Strabismus,Mechanical Strabismus,Comitant Strabismus,Comitant Strabismus, Convergent,Deviation, Dissociated Horizontal,Dissociated Horizontal Deviations,Dissociated Vertical Deviations,Heterophorias,Heterotropia,Horizontal Deviation, Dissociated,Hypertropias,Non Concomitant Strabismus,Noncomitant Strabismus,Phoria,Strabismus, Concomitant,Strabismus, Convergent Comitant,Strabismus, Mechanical,Strabismus, Non-Concomitant,Strabismus, Nonconcomitant
D014792 Visual Acuity Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast. Acuities, Visual,Acuity, Visual,Visual Acuities
D016032 Randomized Controlled Trials as Topic Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table. Clinical Trials, Randomized,Controlled Clinical Trials, Randomized,Trials, Randomized Clinical

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