Conjunctival Settling Of Scleral Contact Lenses.

Background: Scleral contact lenses rest either exclusively on the bulbar conjunctiva or with minor touch at the limbus. It is well accepted across the contact lens community that scleral lenses settle into the conjunctiva with increased wear time. This study aims to determine the extent of settling with various wear time in six types of scleral lenses. This will allow for improvements in fitting of these lenses and provide patients with better care.
Methods: Six patients will be fit in one of six scleral lenses. The initial visit will consist of visual acuity, biomicroscopy, corneal topography, anterior segment optical coherence tomography (AS-OCT), lens fitting, and insertion and removal training. Next the patient will return for the dispensing of the lenses. Visual acuity, overrefraction, biomicroscopy, and anterior segment OCT will be performed over the lenses immediately upon insertion and each hour thereafter for four hours. At the final visit the patient will present wearing their lenses for at least four hours and will have worn the lenses for the previous week. Biomicroscopy, visual acuity, and anterior segment OCT will be performed.
Results: Limited data was available due to poor fit or patient loss to follow-up. Lenses settle into the conjunctiva on average 0.0467mm after one hour of wear and on s 0.0717mm after four hours of wear. The difference in settling between fellow eyes of one subject was on average 0.033mm after one hour of wear and 0.043mm after four hours of wear.
Conclusions: While limited in size, this study appears to indicate that scleral contact lenses do settle into the conjunctiva. This settling should be accounted for during fit of scleral lenses so as not to add bearing on the cornea after extended wear. This study is limited in size and, as such, warrants further research.