C53834: Scleral lenses part 3 – fitting

The previous article in the series discussed the role of scleral contact lenses in modern contact lens practice including their unique benefits, limitations and expanding usefulness. In this article we will address the principles of fitting and provide guidance on how to arrive at a successful fit.

The ideal scleral lens fit

The ideal scleral lens fit will provide minimal corneal clearance to avoid corneal touch after many hours of wear during which time the lens will settle back. All scleral lenses settle back with time as the scleral landing zone beds into the spongy conjunctiva. This is most significant when fitting smaller scleral contact lenses that, as a result, have a smaller baring surface and so greater ‘weight’ per unit area. In practice it is advisable to expect the tear reservoir to thin by up to 150microns during wear as the lens settles back (figure 1). The majority of this will occur during the first few hours but further settling back seems to occur during the first week or so of repeated wear.