Excimer Laser Surgery for Anisometropic Amblyopia

Inclusion Criteria

• •1. Age 3 to \<8 years
• •2. Best-corrected amblyopic-eye VA using the ATS single-surround HOTV letter protocol (ATS-HOTV) meeting the following criteria:
• •* If age 3 to \<5 years, 20/80 to 20/800 (a re-test is required if the VA is 20/80)
• •* If age 5 to \<8 years, 20/63 to 20/800 (a re-test is required if the VA is 20/63)
• •* Note: For participants who require a re-test (as specified above), the better of the test and re-test acuities must meet the eligibility criteria for the amblyopic eye and will serve as the enrollment VA.
• •3. Best-corrected fellow-eye VA meeting the following criteria by ATS-HOTV:
• •* If age 3 years, 20/50 or better
• •* If age 4 to 5 years, 20/40 or better
• •* If age 6 to 7 years, 20/32 or better
• •4. Best-corrected inter-ocular acuity difference ≥ 3 logMAR lines by ATS-HOTV
• •5. Refractive error meeting the following criteria (based on a cycloplegic refraction that is not more than 4 months old):
• •* Refractive error in the amblyopic eye must be greater than the fellow eye.
• •* If the amblyopic eye is myopic, SE refractive error in the amblyopic eye between -3.00D and -12.00D, inclusive.
• •* If the amblyopic eye is hyperopic, SE refractive error in the amblyopic eye between +3.00D and +6.00D, inclusive, if \<=1.00D of astigmatism in the amblyopic eye; and between +3.00D and +5.00D, inclusive, if \>1.00D of astigmatism in the amblyopic eye.
• •* Astigmatism less than or equal to 3.50D in the amblyopic eye.
• •* SE refractive error in the fellow eye between -4.00D and +3.00D, inclusive, with no astigmatism limits.
• •* For participants 3 to \<5 years of age, at least 5.00D of SE anisometropic difference between the two eyes by cycloplegic refraction; for subjects 5 to \<8 years of age, at least 3.00D SE anisometropic difference
• •* No more than 3.00D of difference in cylinder power between the two eyes
• •* Target postoperative refractive error (if participant becomes eligible for randomization) must be achievable with PRK as defined in Table 3 and must be within 2.00D of the fellow eye.
• •6. Prior to enrollment into the Patching Run-In Phase, must have had patching and/or optical penalization with atropine or Bangerter filters prescribed for at least 6 months and optical correction of refractive error prescribed for at least 6 months. Prior treatment does not have to be continuous. Compliance with prescribed treatment does not influence eligibility but the best effort at compliance is expected from both the patient and provider.
• •7. Corneal thickness \>500 microns (\>510 microns within the previous 7 months, or corneal thickness between 500 and 510 microns within the last 2 months).
• •8. Central corneal thickness must be enough to allow the treatment dose needed while leaving a residual corneal thickness of ≥ 375 microns.
• •9. IOP ≤ 22 mm Hg within 7 months of enrollment
• •10. Investigator believes that the participant has achieved maximum improvement in amblyopic-eye VA with conventional treatment.
• •11. Investigator is willing to prescribe patching, and parent and child are willing to attempt patching for at least 8 weeks for 42 hours per week (averaging 6 hours daily) in the Patching Run-In Phase.
• •12. No rigid gas permeable lens (including OrthoK) worn in the past 2 months
• •13. Soft contact lens is currently worn, has been attempted within the past 4 months, or a contact lens fitting exam (paid for by the study) is scheduled or the investigator does the contact lens fitting on the same day as enrollment.
• •14. Parent understands the protocol and is willing to accept randomization (if child meets eligibility criteria after Patching Run-In Phase).
• •15. Parent has a phone (or access to phone) and is willing to be contacted by Jaeb Center staff or other study staff during the next 36 months.
• •16. Relocation outside of area of an active PEDIG site for this study without the next 36 months is not anticipated.