Purpose:
To investigate differences between thin and thick corneas inbiomechanical and tomographic parameters
Methods:
In this retrospective randomized clinical study, 62 eyes of62 refractive surgery patients who presented for screening wereenrolled.The main outcomes monitored were age, pre-operativespherical equivalent on manifest refraction (MRSE), ultrasonicpachymetry (USP), topographic parameters (keratometry values),biomechanical parameters (Corneal hysteresis [CH] and cornealresistance factor [CRF]) and tomographic parameters (cornealvolume [CV] and anterior chamber volume [ACV]). Eyes with aUSP thinner than 520 were included in the thin cornea group(22 eyes) and eyes with a USP thicker than 520 were includedin the thick cornea group (40 eyes).
Results:
The mean corneal thickness in the thin cornea group was 497.8± 14.7 µm and the mean corneal thickness in thethick cornea group was 561.7 ± 24.1 µm (p = 0.003).There were no significant differences in age, MRSE or mean keratometry.(p= 0.456, 0.657, 0.785 respectively). Tomographic values revealedno significant differences between the groups in CV (thin group57.9 ± 2.5 mm3 and thick group 61.3 ± 3.7 mm3p=0.121) and ACV (thin group 203.5 ± 25.5 mm3 and thickgroup 202.5 ± 33.9 mm3 p=0.872). The thin cornea grouphad significantly lower mean CH (8.9 ± 1.5 mmHg) andmean CRF 8.3 ± 1.9 mmHg compared to the thick corneagroup (CH 11.8 ± 2.0 mmHg [p= 0.034] and CRF 10.9 ±2.3 mmHg [p=0.021].
Conclusions:
Corneal thickness does not significantly alter tomographic values.Thin corneas seem to have lower biomechanical values.Supportedby Research to Prevent Blindness, New York, NY
Keywords: refractive surgery: other technologies • refractive surgery: corneal topography