Front Surface Aberration Control in Scleral Lenses for Improvement of Visual Quality in Patients with Corneal Ectasia

This trial will examine the effects of custom front-surface wavefront correction on visual performance and on the neutralisation of higher-order aberrations in patients with corneal ectasia wearing scleral lenses compared to conventional scleral lenses. The clinical trial will be single centre and involve five visits over approximately four months. The investigational devices are the EyeSpace® aberration cancelling (OV) lens and longitudinal spherical aberration (LSA) lens. The OV lens has a custom individualised front surface based on the entire wavefront aberrometry reading in a conventional lens. The LSA lens has -1.00 D of longitudinal spherical aberration on the front surface. The material of the scleral lens will be an FDA-approved polymer for use in rigid contact lenses (Acuity 200™ or fluoroxyfocon A). The device is intended to be worn during the day and removed during hours of sleep. Scleral contact lenses will be fitted by a registered optometrist with training in fitting scleral contact lenses. Participants are required to wear the lenses for at least two hours a day for 20 days between Visit 3, 4 or 5; and for more than 2 hours on the of day Visit 3, 4 or 5. At the start of each visit the patient will be asked if they have worn the lenses for the required time, if not the visit will be rescheduled. This visit will be rescheduled at least week later to ensure they meet minimum wear time. The participants will wear all 3 lenses for 4 weeks each with the lenses being swapped at Visit 3, 4 and 5. As the fit of the lenses are the exact same there will be no washout. Visits will take 1.5 hours a part from visit 5 which requires a three hour break in the middle of the visit. The visits will comprise of an assessment of vision including distance vision, near vision and low contrast vision, an assessment of fit with slit lamp and anterior oct, an ocular health assessment with slit lamp as well as an assessment of residual aberrometry. These assessments will be conducted by an experienced contact lens fitting optometrist.

This is a randomised three-arm crossover, single centre, double blinded study. The study treatment follow-up duration is up to 133 days. To enrol in this study, participants must be in between the ages of 18 and 65, with the aim of recruiting 30 participants. The material of the scleral lens will be an FDA-approved polymer for use in rigid contact lenses (Optimum Infinite or tisilfocon A). The device is intended to be worn during the day and removed during hours of sleep. Scleral contact lenses will be fitted by a registered optometrist with training in fitting scleral contact lenses. The study participants will be examined at the baseline visit (Visit 1) to determine eligibility in either one or both eyes and to determine the lens parameters required. The first study lens will be ordered as a conventional scleral lens (CS), but the participant will be blinded. The CS lens will be dispensed to the participant at Visit 2 as Lens A. If the participant is a neophyte wearer, they will be instructed on the insertion/removal, the use and care/maintenance of the device. The participant will wear lens A for 2 weeks (+/- 7 days). At visit 3 appointment if the fit of the lens is acceptable. The study lenses are then ordered with the same back surface geometry (and therefore, the same fit to the eye) as the CS lens. One of these will have front surface spherical aberration (LSA lens) and the other will have customised wavefront aberration correction known as EyeSpace® aberration cancelling scleral lens (OV lens). The LSA and OV lenses will be randomised to both the participant and the subinvestigator into Lens B and C. At Visit 4, Lens A will be reassessed, the participant will receive Lens B and the investigator will assess the fit and vision of this lens. The participant will wear the lens for 4 weeks (+/- 7 days). At visit 5, after reassessment the participant will return Lens B at this visit and the fit and vision of Len C will be validated and dispensed. At visit 6, re-assessments are performed for Lens C, the participant will then be prescribed their preferred lens. Visits will take up to 1.5 hours each. The visits will comprise of an assessment of vision including distance vision, near vision and low contrast vision, an assessment of fit with slit lamp and anterior oct, an ocular health assessment with slit lamp as well as an assessment of residual aberrometry. These assessments will be conducted by an experienced contact lens fitting optometrist.