Abstract
Purpose :
Scleral contact lenses (ScCL) are becoming increasingly more prescribed among Eye Care Practitioners (ECP). They are often superior to other forms of contact lens treatment for moderate to severe corneal ectasia. They have also been found to be highly effective for the treatment of other corneal diseases such as ocular surface disease. Because they rest entirely on the conjunctiva and sclera, some have suggested that these lenses may cause increased intraocular pressure (IOP). The aim of this study is to determine if SCL affect IOP when worn for 8 hours
Methods :
Seven optometry students (3 males and 4 females) between the ages of 25 – 30, with normal corneas and IOP, were recruited for an Institutional Review Board approved study. The best fit ScCL from a 15.8mm 0.4mm thick trial-lens set was selected for a randomly selected eye. A soft contact lens of the subject’s choice was fitted in the fellow eye and subjects were asked to wear the lenses for about 8 hours, starting from approximately 9:30 AM. Three IOP measurements were taken with rebound tonometer (iCare) prior to lens insertion, and immediately after lens removal. iCare tonometer readings has been shown to correlate with Goldmann tonometer readings. Initial and final lens vault was determined with anterior segment Zeiss OCT. Mean pre-and post-lens wear IOP was calculated for each eye. Mean IOP change for the ScCL eye and the soft lens eye were analyzed with a Student-test and the Bland Altman test.
Results :
For all subjects, the IOP increased in the ScCL eye after 8 hours of lens wear. IOP in the soft lens eye did increase slightly for some subjects but decreased for others, after 8 hours of wear. The mean change in IOP for the ScCL eyes was 5.81 ± 1.62 mm Hg while that of the soft lens eye was -0.62 ± 0.88 mm Hg. The unpaired t-test showed a significant difference (p <0.05, R2=0.5014) between the means. The Bland-Altman bias was 6.43 (SD of bias 3.139), with 95% Limit of agreement from 0.277 to 12.58 (Fig 2). ScCL settling ranged from 56 µm to 200 µm, with a mean of 104 ± 53.62 µm. There was no correlation between IOP change and amount of settling.
Conclusions :
This study shows that wearing a scleral lens for 8 hours can increase IOP in a normal patients. Some subjects showed more of an incrase than others. ECP must consider this possible outcome in treating patients with ScCL and prudent measures should be in place to monitor the IOP in patients wearing ScCLs.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.