Results from the 36-month Hyperopia Treatment Study 1 (HTS1) comparing immediate versus delayed spectacle treatment for moderate hyperopia in children 1 to <3 years of age are consistent with showing a small to moderate benefit or no benefit of immediate glasses compared with careful observation and glasses if deterioration occurs.
The study randomized patients 1:1 to either observation with glasses not prescribed unless the child met deterioration criteria or immediate prescription of glasses to be worn for the study duration. Its primary outcome, analyzed at study conclusion, compared rates of failure at study conclusion, with failure defined as “doing harm” to visual acuity, stereoacuity, or alignment.
The results showed a 13% lower failure rate in the group randomized to immediate glasses compared with the observation group (21% vs. 34%), but the difference between groups was not statistically significant (P=.14).
The findings from the National Eye Institute-supported study conducted by the Pediatric Eye Disease Investigator Group were reported for the first time by Donny W. Suh, MD, at the Pediatric Subspecialty Day meeting.
Dr. Suh said, “Our estimates of failure after 3 years with follow-up every 6 months did not allow us to make any definitive recommendations about management for these children.”
Noting that the study has definite limitations, he concluded, “We all agree that further studies are needed to answer this question effectively.”
The study was undertaken because it remains controversial whether young children with moderate to high hyperopia in the absence of strabismus or amblyopia should be prescribed glasses immediately or observed until some sign of decompensation develops.
“You can find literature to support both practices,” said Dr. Suh, chief of Pediatric Ophthalmology and Strabismus, Children’s Hospital and Medical Center, and associate professor, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE. “The main question our study asked was, If you delay treatment until the child decompensates or deteriorates, will it cause any permanent damage or harm?”
Children were eligible for HTS1 if on cycloplegic refraction they had +3.00 D to +6.00 D spherical equivalent refractive error in either eye, astigmatism ≤1.5 D in both eyes, and spherical equivalent anisometropia ≤+1.50 D.
In addition, they could not have received prior treatment for refractive error with glasses unless the duration was ≤1 week and the treatment occurred > 2 months prior to enrollment. They also could not have prior treatment for amblyopia or strabismus or measurable heterotropia at distance or at near by cover/uncover testing.
Dr. Suh reviewed the protocol definitions and criteria for failure and deterioration. He explained that failure, which was defined at the end of the study, was declared if any of the following criteria were met with and without trial frames and with confirmation by masked test and retest: measurable heterotropia; visual acuity below age norms; stereopsis below age-normal values; or strabismus surgery prior to the 36-month exam.
Deterioration was declared if any of the following criteria were met on unmasked testing in randomized correction and confirmed by retest: measurable heterotropia; if age ≥3 years, VA below age-normal values, significant IOD, or steroeacuity below age-normal values; or parental concern. Rates of deterioration during the 3-year study were 33% for the group prescribed immediate glasses and 58% for the observation group.
Dr. Suh noted that the rates of deterioration matched prestudy expectations, and he observed, “About one-half of patients were followed without glasses for 3 years.”
Emmetropization over the study period was also evaluated using data from the more hyperopic eye. Dr. Suh reported that on average, hyperopia changed little in either group, and there was a between-group difference in the amount of change of just 0.16 D that was not statistically significant.
Discussing the study’s limitations, Dr. Suh said that the study had a planned enrollment of 286 patients, but enrollment was slow and only 130 patients completed the trial.
In addition, the study did not address the effect of correction on asthenopia, near visual acuity or reading performance.