There was a significant reduction in corneal thickness measured using computerized videokeratography in both groups at 36 months ( control group : -17.013.63 m , P < 0.001 ; treatment group : -19.525.06 m , P < 0.001 ) that was not observed in the treatment group using the manual pachymeter ( treatment group : +5.864.30 m , P = 0.181 ) .