In this opinion article, Sandra M. Brown, MD, argues that despite enthusiasm from some in the refractive community, much more study is required before refractive surgery is considered appropriate treatment for pediatric eye disorders. Dr. Brown writes that much of the literature on this subject is of marginal value due to a conceptual misunderstanding of childhood cortical vision development coupled with poor study design, omission of critical information and wishful thinking.
Refractive surgery in younger children to reduce anisometropia could theoretically facilitate amblyopia treatment that has stalled due to noncompliance. But study results have not shown this to be the case, she says. While refractive surgery treats the refractive error, it does not address the amblyopia that is secondary to severe anisometropia. And no study to date has shown refractive surgery induces greater compliance with amblyopia therapy.
She lists a variety of factors that put children undergoing myopic or hyperopic ablation at increased risk for serious loss of quality of vision, including high-dioptric treatment, a small functional optical zone, ablation decentration or uneven ablation due to unstable fixation and a large pupil. In addition, surgery at a young age prevents children from receiving the most technologically advanced procedures, such as wavefront-guided LASIK due the level of cooperation required during wavefront testing and near-perfect ablation centration.
Lens extraction surgery in children with unilateral high myopia accompanied by amblyopia, strabmismus, nystagmus and cognitive difficulties "seems particularly difficult to justify on a functional basis," she writes. Surgery increases the risk of retinal detachment, which may be exacerbated by eye rubbing which could also lead to chronic uveitis or IOL dislocation. The phakic IOL also carries long-term risks of corneal decompensation, cataract, pigment dispersion, uveitis and glaucoma.
"Intraocular refractive procedures in young children for indication other than cataract may ultimately follow hexagonal keratotomy to the dustbin labeled "we knew it was a bad idea when we did it," she writes.
She advises that refractive surgeons collaborate with pediatric ophthalmologists on designing and conducting prospective studies.
Brown recommends dividing pediatric refractive surgery studies into two groups: those performed on visually mature children for optical benefits, such as reduction of refractive error, that may serve to improve ocular alignment or sensory binocular integration, and those intended to facilitate amblyopia management. Children older than 7 years should not be included in amblyopia studies, nor should those ages 6 to 7 years with corrected visual acuity worse than 20/200, due to low likelihood of functionally significant amblyopia improvement. Only those mature enough to provide a reliable optotype-recognition visual acuity should be enrolled in refractive surgery studies. The author adds that studies on visually mature children should include an assessment of their daily vision function with and without correction, since recovery of low-grade stereopsis is of limited practical benefit for most activities of daily living.