Aggravated Lens Decentration Not Common After Ortho-K in Exotropic, Exophoric Eyes

Aggravated lens decentration (LD) after orthokeratology (ortho-K) lens application is not a common complication for patients with intermittent exotropia (IXT) and exophoria (XPH), according to research published in Ophthalmology and Therapy. 

Researchers conducted a multi-center, prospective cohort study to assess whether children with intermittent exotropia and exophoria could wear ortho-K lenses without experiencing aggravated lens decentration.

The team measured uncorrected visual acuity and corneal topography at baseline and after 1 month of ortho-K lens wear and assessed aggravated lens decentration. They also evaluated the relationship between lens decentration and potential risk factors. 

A total of 123 patients with myopia (age range, 8-14 years) were included in the study, 38 with intermittent exotropia, 52 with exophoria, and 33 with orthophoria. 

After 1 month of treatment, the researchers found no significant difference in magnitude and direction of lens decentration among the groups; the magnitude of treatment zone decentration ranged from 0.49-0.51 mm for polar decentration (P =.289), from -0.28 to -0.40 mm for horizontal decentration (P =.236), and from -0.14 to -0.21 mm for vertical decentration (P =.567). 

The team observed severe decentration in 1 (2.6%) patient with intermittent exotropia, 2 (3.8%) patients with exophoria, and 1 (3.0%) patient with orthophoria (P =.947). They found that inferotemporal lens decentration was most common in all groups (intermittent exotropia, 50.0%; exophoria, 76.9%; orthophoria, 72.7%). 

With multivariate analysis, the researchers found significant associations between polar decentration and the surface asymmetry index (b=0.21; 95% confidence interval [CI], 0.02–0.40; P =.028) and the surface regularity index (b=-0.39; 95% CI, -0.66 to -0.13; P =.004), but not the magnitude of deviation (b=-0.00, 95% CI, -0.01–0.00; P =.180).

“In our study, among IXT, XPH, and orthophoria groups, we did not find any statistical difference either in magnitude or direction of LD,” the researchers report.

Limitations of the study included confirmation of non-aggravated lens decentration of ortho-K in patients with intermittent exotropia and exophoria only and a limited range of deviation in patients with intermittent exotropia.