The impact of contact lenses on binocular vision in patients with Keratoconus.

BACKGROUND

To compare the effect of corneal rigid and scleral contact lenses (CRCL & SCL) on binocular vision and accommodative function in keratoconus (KCN) patients.

METHODS

In this prospective non- randomized comparative interventional study, patients aged 20 to 40 years with a definitive diagnosis of KCN were participated. Only patients with the best-corrected visual acuity (BCVA) of 0.40 LogMAR or better were included. A comprehensive examination including assessment of BCVA, refractive error, and stereopsis were performed. Furthermore, all participants underwent the complementary binocular vision and accommodation testing. All examinations were performed by spectacle and then repeated after contact lens fitting in both groups.

RESULTS

In total, 31 patients were recruited (12 in the CRCL group and 19 in the SCL group). Both groups demonstrated significant improvements in BCVA after lens fitting in both eyes, with the SCL group showing an average gain of approximately 1-3 lines. Additionally, a higher proportion of patients in the SCL group achieved central stereopsis (<100 sec/arc) following lens fitting (p = 0.011).

CONCLUSIONS

While both SCL and CRCL contributed to improved visual acuity in patients with KCN compared with spectacle, SCL exhibited more advantages over CRCL, particularly in enhancing stereopsis and fusional vergence performance.