Anisohyperopia Treatment Fails to Yield Axial Length Increases

Anisohyperopia treatment using a relative peripheral hyperopic defocus (RPHD) soft multifocal contact lens does not result in significant axial length increases when used as an intervention in the eye with a greater amount of hyperopia, according to research published in Ophthalmic and Physiological Optics. However, the untreated contralateral eyes experience accelerated axial growth during this treatment, the report shows.

Researchers included 11 pediatric patients with anisohyperopia (mean age, 10.56 years; girls, 8) in the prospective, controlled study to determine whether RPHD accelerates axial growth and affects refractive error in individuals with the condition. Study participants underwent 6 months of single vision spectacle treatment before crossing over to anisohyperopia treatment for 2 years — an intervention that consisted of inserting a RPHD center-near soft multifocal contact lens in the eye with greater hyperopia and correcting vision in the fellow eye with a single vision contact lens if necessary. The cohort returned to single vision lens treatment for another 6 months after completing the intervention. The research team monitored axial growth and refractive error changes during the 3-year study duration.

Overall, axial length (AL) changed during the study (F_[6,60], 14.81; P <.001), but only in the untreated control eye (F_[6,60], 2.61; P =.03). In eyes undergoing anisohyperopia treatment, mean AL was 21.67 mm at baseline, which increased to 21.84 mm at the study conclusion. Axial growth increases in the untreated control eyes only took place during the treatment period, and not while participants wore single vision lenses, according to the report.

Neither eye demonstrated significant refractive error changes during anisohyperopia treatment (treatment eye, −0.23 diopters [D]; control eye, −0.30 D), and refractive error remained stable during spectacle lens treatment.

“For anisohyperopes, instinctively, the eye closer to emmetropia (the control) would be regarded as the ‘normal’ eye,” the researchers explain. “However, given that the mean growth rate for the more hyperopic eye in the present work was closer to the expected norm, should the control eye be considered as the ‘abnormal’ one of the pair? With this in mind, perhaps the primary endeavor should be to slow down growth in the least hyperopic eye, rather than attempting to accelerate growth in the more hyperopic eye.”

Study limitations include a small sample size and failure to assess earlier anisohyperopia treatment intervention in participants younger than 8 years.