April 18, 2019
2 min read

Study recognizes learning curve associated with scleral lens fitting

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Practitioners with no or minimal previous training can rapidly improve their ability to fit scleral gas permeable contact lenses, both in regular and irregular corneas, according to a study.

Eighty-five subjects (156 eyes) were included in a prospective dispensing trial in which a licensed optometrist with no previous experience of fitting scleral lenses was evaluated for the number of trial lenses used to prescribe and order each lens and the number of reorders before a fully satisfactory result was achieved.

Patients were divided in two groups, the first with primary or secondary corneal ectasia, previous keratoplasty and other corneal irregularities and the second with regular corneas in which other forms of contact lens vision correction had failed.

The number of trial lenses used before the optimal fitting was achieved decreased from a mean of 2.35 lenses in the first 20 fittings to a mean of 1.56 lenses in the last 16 fittings. The number of trial lenses required began to drop significantly after fittings 61 to 80. No statistically significant difference was found between the number of trial lenses needed for fitting irregular and regular corneas. However, postsurgical corneas and corneas with high astigmatism required more trial lenses.

Reorders decreased over time from almost one reorder per subject to one reorder per four subjects, with the decrease beginning after the 60th fitting. Most of the reorders were due to a combination of poor vision and inadequate fit. About 10% of the subjects required a reorder due to discomfort despite the fitting seeming satisfactory. In most cases, refitting with toric lenses resulted in improved comfort.

This study demonstrates that, “after the first fittings, a novel practitioner would be able to significantly reduce the number of trial lenses and reorders to the manufacturer,” the authors wrote.

“Understanding this learning curve is relevant for manufacturers and clinicians, as this will directly impact the number of lenses required to accomplish a successful fitting,” they wrote. – by Michela Cimberle

Disclosure: The authors reported no relevant financial disclosures.