Abstract
Purpose: :
To compare post-LASIK central corneal thickness (CCT), using Orbscan IIz, OCT Visante and ultrasonic pachymetry and correlate measurements of flap thickness by prestablished microkeratome plate and OCT Visante.
Methods: :
The post-LASIK CCT was measured one week using only Orbscan IIz ((Bausch & Lomb, Germany) and OCT Visante (Carl Zeiss, Germany), and month after surgery with the same instruments and ultrasonic pachymetry (Accutome Ultrasound, Malvern, Pa). In addition, the corneal flap thickness was measured by OCT Visante and was correlated with estimated value of the microkeratome. Patients were divided in two groups depending on the microkeratome used: Group I Hansatome (Bausch & Lomb, Germany) , 160 µ plate ; and Group II: Moria (Moria, France) 130 µ plate .
Results: :
A total of 40 eyes were examined. The mean post-LASIK CCT at first week obtained with Orbscan IIz was 461.7 ± 53.1µ[[Unsupported Character - ]][[Unsupported Character - ]] and with OCT Visante was 486 ± 44.6 µ, with a mean difference of 24.3 µ (p=0.02). One month after surgery, the mean CCT obtained with Orbscan IIz was 470.6 ± 47.3 µ, with OCT Visante was 484.1 ± 38 µ, [[Unsupported Character - ]]and with ultrasonic pachymetry was 492.1 ± 42.7 µ. The mean difference between Orbscan IIz and OCT Visante was 13.5 µ (p=0.16), between Orbscan IIz and ultrasonic pachymetry was 21.5 µ (p=0.03) and between OCT Visante and ultrasonic pachymetry was 8 µ (p=0.37). The mean corneal flap thickness by OCT Visante was 150.7 ± 3.82 µ in group I (p= 0.02) and 137.5 ± 4.5 µ in group II (p=0.03).
Conclusions: :
Orbscan IIz post-LASIK CCT measurements are thinner than those obtained with OCT Visante and ultrasonic pachymetry. Measurements with OCT Visante and ultrasonic pachymetry are highly correlated. Corneal flap thickness measured with OCT Visante does not correlate well with prestablished microkeratome plate.
Keywords: refractive surgery: LASIK • refractive surgery: corneal topography • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)