Clinical evaluation of a custom-made toric soft lens.

OBJECTIVE

The fitting of toric soft contact lenses is often complicated by interference between the toric optics and the geometry need to stabilise the lens on the eye. The use of a spherical trial lens to determine the parameters of a toric soft contact lens can lead to unintended positioning and movement of the lens ordered. The purpose of this study was to evaluate clinically the success.

OBJECTIVE

The fitting of toric soft contact lenses is often complicated by interference between the toric optics and the geometry needed.

METHODS

The design of the lenses used was such that optical correction and stabilisation were separated. The lenses had a back tonic surface limited to the central optical zone and base down prism stabilisation in the periphery. The empirical system used corneal radii, spectacle refraction and horizontal visible iris diameter as lens design parameters.

RESULTS

This multi-centre trial, comprised of 105 patients (193 eyes), revealed an overall success rate of 86%. The total number of lenses ordered to achieve success was 1.46 per eye in new patients and 1.69 per eye in patients who were failures with other toric soft lenses. In 14% of the cases success could not be achieved despite ordering several lenses (up to 4 lenses/eye). Many of these patients (60%) were also failures with other toric soft lenses.

CONCLUSIONS

It is concluded that in new patients successful toric soft contact lens fitting can be achieved with an empirically based method. When refitting former toric soft lens failures, we recommend discontinuation after two further unsuccessful fittings.