Surgery for Amblyopia Improves Behavior, Quality of Life

From Medscape Medical News

Norra MacReady

April 5, 2011 (San Diego, California) — Children with developmental disorders and severe ametropia and amblyopia show objective improvements in behavior and development after photorefractive keratectomy (PRK), Evelyn Paysse, MD, reported in an oral presentation here at the American Society of Pediatric Ophthalmology and Strabismus (AAPOS) 37th Annual Meeting.

Most children with these conditions wear corrective lenses, explained Dr. Paysse, who is associate professor of ophthalmology at Baylor College of Medicine in Houston, Texas.
However, there is a subset of patients who will not wear them, such as children who were born prematurely, autistic patients, and children with cerebral palsy, genetic disorders, and craniofacial abnormalities.

Often these children find glasses inconvenient or uncomfortable. For example, neck hypotonia makes it difficult for a patient to keep her head up, so her glasses will be continually sliding off her nose, Dr. Paysse noted. Children with seizure disorders might fear losing or breaking their glasses during an episode, and children with cognitive or behavioral conditions might find glasses frightening or anxiety-provoking.

Using a term coined by Lawrence Tychsen, MD, from Washington University School of Medicine in St. Louis, Missouri, Dr. Paysse said these children have a kind of "visual autism. They live in a world of blur and isolation, where visual stimuli might be experienced as noxious or averse because they are not seen until they are very close to the face. . . . This increases the stress in these already severely impaired children."

There are about 60 published cases of refractive surgery in this patient population, Dr. Paysse said. The procedure has been associated with improved vision and quality of life, as reported in parent questionnaires, but these findings have been criticized on the grounds of "possible bias because the parents are highly motivated to see an improvement."

Dr. Paysse and her colleagues decided to measure outcomes objectively by subjecting the patients to a well-validated battery of developmental tests just before and 6 months after undergoing PRK.

The patients were 14 children, ranging in age from 4 to 11 years (average age, 5.5 years), with high bilateral ametropia and amblyopia. They had a variety of neurodevelopmental conditions such as autism, Down's syndrome, severe attention deficit hyperactivity disorder, and cerebral palsy. Minimum refractive errors were bilateral myopia of at least 6 diopters (D), bilateral hyperopia of at least 4 D, and bilateral astigmatism of at least 3 D. All of the children refused to wear glasses and were unable to wear contact lenses. With PRK, they were corrected for a maximum treatment dose of –10.43 D for myopia or +5.43 D for hyperopia. Mean postoperative cycloplegic refraction was –1.86 ± 1.85 D for the myopic group and +0.49 ± 1.34 D for the hyperopic group.

Depending on their age and level of function, the children underwent the Vineland Adaptive Behavior Scales, Second Edition (Vineland II); the Beery Burktenica Developmental Test of Visual-Motor Integration, Fifth Edition (Beery VMI); or the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley). These tests evaluated the patients' communication, socialization, motor, and adaptive abilities, as well as their daily living skills, both before and 6 months after undergoing PRK.

The primary outcome measure was a change in the developmental quotient (DQ) in the subdomains, measured as mental age in months/biological age in months multiplied by 100. "The DQ is a very well-used metric in developmental pediatrics," Dr. Paysse said.
Unlike normal children in whom mental age increases with biological age, mental age eventually reaches a plateau in many children with developmental disabilities as their biological age advances, leading to a gradual worsening of the DQ.

In the communication domain, as measured by the Vineland II, the children in this study had a mean preoperative receptive DQ of 23.8 and a postoperative DQ of 31.7 (P = .04), and a mean preoperative communicative DQ of 25.7 and a postoperative communicative DQ of 31.0 (P = .02). In the socialization domain, preoperative and postoperative interpretive DQs were 24.0 and 28.2, respectively (P = .04), and preoperative and postoperative coping DQs were 20.3 and 28.1, respectively (P = .02). Dr. Paysse called these improvements "remarkable." Scores in the other subdomains remained the same, which means that the patients did not show the expected worsening in DQ that comes with time, "and this may be remarkable as well."

"I definitely appreciated Dr. Paysse's use of formal behavioral tests in these children," said Sandra Brown, MD, a pediatric ophthalmologist in private practice in Concord, North Carolina. "I compliment her on this study."

These findings suggest that PRK can improve vision and refractive error in children with neurobehavioral disorders and high isoametropic amblyopia, and there is an associated improvement in the developmental functions of communication and socialization, Dr. Paysse concluded. "This translates into an improved quality of life."

Dr. Paysse and Dr. Brown have disclosed no relevant financial relationships.

American Society of Pediatric Ophthalmology and Strabismus (AAPOS) 37th Annual Meeting: Paper 17. Presented March 31, 2011.