Data for: Performance of corneal vs. scleral rigid gas permeable contact lenses for ectatic corneal disorders

Published: 10-01-2020| Version 1 | DOI: 10.17632/gmrbh4fvt2.1
Alex Levit,
Martin Benwell,
Bruce Evans


Introduction. Keratoconus and related corneal ectatic disorders are typically managed with corneal rigid gas permeable contact lenses (CRGPcl). When these are unsuccessful patients may be fitted with scleral rigid gas permeable contact lenses (SRGPcl). It has been hypothesised that the use of SRGPcl in the management of ectatic corneal disorders should be expanded and SRGPcl may even considered as the first option. The present research investigates this hypothesis. Purpose. To compare the performance of CRGPcl versus SRGPcl in participants with keratoconus, who are successfully wearing “habitual” CRGPcl. Methods. RCT) with a 2x2 crossover, 34 participants were recruited. The outcome measures were: Early Treatment Diabetic Retinopathy (ETDRS) log of minimum angle of resolution (logMAR) best corrected visual acuity (BCVA); VectorVision 1000E contrast sensitivity function (CSF), expressed in both numeric and log contrast sensitivity (logCS); National Eye Institute Visual Function Questioannaire-25 (NEI-VFQ) to assess the visual Qol; and reported o a scale from 1–10, the Levit Subjective Vision Scores (LSVS) and the Levit Subjective Comfort Scores (LSCS). The final outcome was the selection of the preferred lens type at research completion. Results. The only measures, which exhibited statistically significant differences between the two lens types, rejecting H0, were the LSCS, which was significantly higher in SRGPcl (p=0.002). The LSCS whilst wearing the experimental CRGPcl, was significantly higher in participants who selected CRGPcl [N=16, (52%)] as their preferred lens for future use, compared to those who selected SRGPcl (p=0.009). All other outcomes supported H0. The Final lens choice: CRGPcl were preferred by 53% (n=16) and SRGPcl by 47% (n=14). Conclusion. The research population exhibited significantly better comfort in SRGPcl compared with CRGPcl. Significantly higher comfort in CRGPcl was found in those who preferred CRGPcl, than those who preferred SRGPcl. Furthermore, Successful CRGPcl wearers whose LSCS in CRGPcl is < 7 are likely to achieve better comfort / tolerance with SRGPcl. This research indicates that on average, successful CRGPcl wearers find SRGPcl more comfortable and there should be no visual and visual Qol advantage or disadvantage in refitting successful keratoconic CRGPcl wearers with SRGPcl and vice versa.