Change in vault during scleral lens trials assessed with anterior segment optical coherence tomography

To assess the change in vault during scleral lens fitting with anterior segment optical coherence tomography (AS-OCT).

This study comprised of patients who had AS-OCT performed after 1h and 4h of scleral lens wear (PROSE, prosthetic replacement of the ocular surface ecosystem, Boston Foundation for Sight, Needham Heights, MA, USA). Vault was measured on AS-OCT as the distance between the front surface of the cornea in the center and the back surface of the scleral lens.

Fifty eyes of 41 patients were analyzed. The main indications for scleral lens trial were ectasia (keratoconus, post surgery) (n=20 eyes) and ocular surface disease (OSD - Stevens - Johnson syndrome, dry eyes and limbal stem cell deficiency) (n=30 eyes). Mean age of the patients was 31.4 years. Twenty were males. The diameter of the scleral lens ranged from 16mm to 18.5mm. Vault measurements reduced in 45/50 eyes (90%), remained same (n=2) or increased (n=3). Overall mean vault decreased from 680±421μm at 1h to 589±355μm (p=<0.001) at 4h of lens wear. Mean vault in ectasia was 759±574μm and 634±455μm (p=0.02) at 1h and 4h of lens wear respectively. In OSD group, mean vault was 626±276μm and 558±273μm (p<0.01) at 1h and 4h of lens wear respectively. Average reduction in the vault was 125μm in ectasia and 68μm in OSD group.

Vault reduced significantly after 4h of lens wear during scleral lens trial indicating that the final assessment of the scleral lens may be done after 4h of lens wear.