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Study: Occlusion therapy with glasses works well with large anisometropias
LASIK is not needed to correct larger errors.
SAN DIEGO — The decision to correct anisometropic myopia with refractive surgery should not be based on the degree of difference between the two eyes, researchers said.
Occlusion therapy with spectacle correction delivers good results regardless of the degree of anisometropia.
Shilpa A. Desai, MD, and Marijean M. Miller, MD, of the George Washington University Department of Ophthalmology, presented their results in a poster session held here at the American Association of Pediatric Ophthalmology and Strabismus (AAPOS) meeting.
“There are people out there advocating laser in situ keratomileusis [LASIK] for patients who have high degrees of anisometropia. What we are saying is that even patients with high anisometropia can achieve good vision with conventional amblyopia therapy,” Dr. Desai said.
Compliance stressed
Dr. Miller said, “When we set out to do this project, we were concerned that presenters at AAPOS from other countries were doing LASIK on kids, and we were not quite sure of the rationale behind that. So I set out on this project, thinking that there might be some cutoff above which the degree of anisometropia would actually justify considering LASIK in a controlled trial.”
Drs. Desai and Miller searched the Children’s National Medical Center database for patients with myopia, anisometropia and amblyopia seen between 1986 and 1992. Anisometropia involved at least 1 D of difference and amblyopia involved at least two lines of vision reduction.
They reviewed 139 patients and found 36 patients with more than 1 D of myopic anisometropia. They excluded patients with organic eye disease, glaucoma and microphthalmia, leaving them with 22 patients.
All patients were patched and later evaluated for compliance on a scale of 0 (for poor compliance) to 2 (for good compliance).
Patients with better compliance and more frequent office visits had better visual outcomes.
“This suggests to me that patients with high unilateral myopia and amblyopia do have a good chance of success with glasses correction and occlusion therapy,” Dr. Desai said.
Degree of error
There was no correlation between the degree of anisometropia and the outcome. Researchers converted all visual acuity measurements to logMAR units. Of the 22 patients, 11 succeeded with amblyopia treatment. Children with successful outcomes had a logMAR visual acuity of 0.2. Children with unsuccessful outcomes had a logMAR visual acuity of 0.83.
The results did not show that any cutoff existed for degree of anisometropia, Dr. Miller said. Seven patients with more than 7 D of anisometropia had successful outcomes.
Researchers concluded that the decision to apply refractive surgery to children will require controlled clinical trials and cannot simply be based on the severity of myopic anisometropia.
“If patients come back for follow-up and are compliant with their treatment regimen, they have a good chance of doing well,” Dr. Desai said.
For Your Information:
- Shilpa A. Desai, MD, is completing her residency at George Washington Medical Center, and can be reached at 9131 Pascataway Road, #150, Clinton, MD 20735 U.S.A.; +(1) 301-868-8300; fax: +(1) 301-868-7250.
- Marijean M. Miller, MD, is assistant professor at George Washington University and attending physician at Children’s National Medical Center. She can be reached at the George Washington University Department of Ophthalmology and the Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC 20010-2970 U.S.A.; +(1) 202-884-3017; fax: +(1) 202-884-6521.