bilateral refractive amblyopia treatment study

Conditions: Bilateral Refractive Amblyopia

Summary: the purpose of this study will be to: * determine the amount of visual acuity improvement with treatment of presumed bilateral refractive amblyopia * determine the time course of visual acuity improvement with treatment

there is a paucity of literature on bilateral amblyopia that is due to a substantial amount of refractive error (hypermetropia or astigmatism), and it is limited principally to review articles and case reports. the incidence is not known, but in one study, 4 of 830 (0.5%) children examined at the time of entry into school had bilateral amblyopia. schoenleber et al performed a retrospective review of office records and identified 184 children with \> +4.00 diopters of hypermetropia in both eyes, 12 of whom (6.5%) had bilateral amblyopia of 20/50 or worse. ten of the 12 children (83%) improved to 20/40 or better in both eyes over a mean follow-up time of 22 months. werner and scott reported 6 cases of bilateral hypermetropic amblyopia with a spherical equivalent of at least +5.00 d and an initial visual acuity of 20/40 or worse in both eyes. all 5 patients with follow up improved with glasses alone, and 2 of these 5 had a most recent visual acuity worse than 20/40 in one eye with follow-up less than one year. cavazos et al identified 218 eyes with hyperopia \> +5.00 d or astigmatism \>+2.00 d. of these, 82 (38%) of the dominant eyes had an initial corrected visual acuity less than 20/25. most improved to \> 20/25, but many patients were lost to follow-up. in ongoing studies, bilateral refractive amblyopia is being evaluated in native americans. 1. patients will be enrolled who have bilateral refractive error with hyperopia \>+4.00 d and/or astigmatism \>2.00 d and have visual acuity in each eye, measured using best correction derived from cycloplegic refraction, meeting the following criteria: * using e-etdrs testing for patients age 7 to \<11 years: visual acuity 20 to 70 letters (20/40 to 20/400) * using ats hotv testing for patients age 3 to \<7 years visual acuity 20/50 to 20/400 2. enrolled patients will be prescribed spectacles, which will be paid for by the study. 3. the patient will return for a spectacle baseline visit within 30 days, at which time the spectacles will be placed on the patient for the first time and binocular and monocular visual acuities will be measured. * patients whose monocular acuity at the spectacle baseline visit is 20/25 or better in both eyes will end the study * patients whose monocular acuity at the spectacle baseline visit is worse than 20/25 in at least one eye will begin a one-year period of study follow up 4. follow-up visits are required at 5±:1 week, 13±:2 weeks, 26±:4 weeks, and 52±:4 weeks. * if at any follow-up visit a patient's monocular acuity is 20/25 or better in both eyes, the patient should return for the 52-week visit only and may skip the interim follow-up visits. sample size: the study plans to enroll 100 patients. at least 50 patients will be enrolled who have an interocular difference of less than 3 lines by ats hotv or less than 15 letters by e-etdrs at the spectacle baseline visit.

Eligibility criteria:
inclusion criteria: * age 3 to \<11 years * able to perform single-surrounded single optotype visual acuity using the ats hotv protocol for children 3 to \<7 years old and using the e-etdrs protocol for children 7 to \<11 years old * monocular visual acuity in each eye, measured using trial frames or phoropter with best correction derived from cycloplegic refraction, meeting the following criteria: * using e-etdrs testing for patients age 7 to \<11 years: visual acuity 20 to 70 letters (20/40 to 20/400) * using ats hotv testing for patients age 3 to \<7 years acuity 20/50 to 20/400 * refractive error that meets at least one of the following criteria in each eye: * spherical equivalent \>+4.00 d * astigmatism \>2.00 d * investigator believes that the patient's reduced visual acuity is due to bilateral, refractive amblyopia * investigator not planning to prescribe occlusion, patching or any other amblyopia treatment other than spectacles at this time * cycloplegic refraction and ocular examination within 2 months prior to enrollment exclusion criteria: * myopia greater than -6.00 d of spherical power in plus cylinder form * ocular cause for decreased acuity in either eye; nystagmus per se will not exclude a patient from the study * refractive correction (spectacles or contact lenses) in past three months and no more than one month of refractive correction ever * prior treatment for amblyopia (other than the refractive correction permitted in previous exclusion criteria) * prior intraocular or refractive surgery * use of contact lenses during the study

Keywords: amblyopia bilateral amblyopia refractive error