A independent practitioner trial was conducted two months prior to the release of EyeSpace in Australia, New Zealand and South Africa.

In summary, there was a first fit success rate of 79%, and all those eyes not successful on first fit were successful on second fit.

This article describes the protocol and results.

Introduction

EyeSpace was released on October 18, 2013 in Australia, New Zealand and South Africa. Prior to release an independent practitioner fitting trial was conducted to test the first fit success of the myopic orthokeratology lens design. First fit success was defined as a lens order where no remakes were required to achieve a satisfactory result. We consider a satisfactory result to be when the patient presents at each follow up appointment with an unaided visual acuity of 6/6 (20/20) or better. The patient must also report the lens as being comfortable enough to wear overnight, and report that their visual acuity remains relatively stable throughout the day.

Six independent practitioners were selected in New Zealand who had prior myopic orthokeratology fitting experience. All were asked to read the Forge/EyeSpace quick-start guide. The Forge quick-start video guide is available here to review.

Practitioners were asked to upload maps to the EyeSpace software, follow the lens designer wizard and click order after the EyeSpace software had created a lens simulation. No modifications were made to lens simulations prior to order by either the practitioner or the distributor. Following the completion of the trial practitioners were required to fill out a results form online.

Forge lens description

A 5 zone, rotationally symmetric, customizable, topography based, aspheric, orthokeratology lens for the correction of low to moderate myopia (-1.00D to -5.00D).

This rotationally symmetric lens should be fitted to a cornea with low corneal toricity. We determine this to be a cornea where there is a difference in corneal height of less than 30 microns between the principal meridians, at 4.5 mm from the instrument axis, which roughly corresponds to the geometric centre of the cornea.

Patient inclusion criteria

  • No anterior or posterior segment pathology
  • Lid disease treated prior to orthokeratology
  • Can either be existing contact lens wearers or new wearers, but no history of orthokeratology
  • Spherical corneae or mildly astigmatic (less than -1.50D corneal cylinder)
  • Low myopes with between -0.50D and -4.50D of spherical correction required
  • Sphero-cylindrical prescriptions allowed, but spectacle cylinder not greater than corneal cylinder
  • Patients must be older than eight years
  • Patients must not be presbyopic

Appointments and follow up for the practitioner

  • Overnight (first night of wear).
  • One week.
  • Two weeks.

At each follow up, Medmont topography maps, slit lamp evaluation, refraction and visual acuity was measured.

After the two week review practitioners were asked to complete a report for each eye that was fitted, outlining the clinical outcomes, refractive changes, and whether the patient was happy with the comfort of the lens.

Results

28 eyes from fourteen patients were fit during the trial. Of this group, 22 eyes did not require a remake in order to achieve a satisfactory result; giving a first fit success of 79%.

The remaining 6 eyes required a remake, which involved adjusting the parameters of the posterior surface of the lens and ordering a new lens. In every case this gave an satisfactory result.

In summary, there was a first fit success rate of 79%, and all those eyes not successful on first fit were successful on second fit.

Further studies should look more closely at the reasons behind an unsuccessful first fit. Longitudinal analysis of the successful lenses could include the expected length of time before replacement is necessary, and may be reported on in future.