Research conducted by the Keck School of Medicine at the University of Southern California in the US has found average replacement time of scleral lenses is about 24 months (±14.3 months) and increases with scleral lens wearing experience.  

In a cohort of 251 patients (120 men and 131 women) with an average age of 57.1±17.4 years (range 9–93 years). The average replacement period for a scleral lens was 23.9±14.3 months (range 5-2617 days). 

Study findings showed patients with greater scleral lens experience had a statistically significant increase in their average scleral lens replacement period: for every one year of additional experience wearing scleral lenses, the average replacement period increased by 30.7 days. There was no statistically significant correlation between average scleral lens replacement period and gender, diagnosis, prior outside scleral lens treatment, lens brand or lens diameter. 

The authors recommended further studies to better understand the impact of scleral lens age on ocular health and vision.  

The study, Average Scleral Lens Replacement Period at a Tertiary Care Hospital, was published in Eye & Contact Lens.