Reliability of manual segmentation of cornea, contact lens and tear film using a high-resolution OCT

In this study, we aimed to evaluate the intra/inter-session and intra/inter-observer variability of manual segmentation of thickness of the pre-lens tear film, contact lens (CL), post-lens tear film, epithelium, bowman’s layer, stroma and the whole cornea and CLs with a flat and a steep fit, using a commercial high-resolution spectral domain optical coherence tomographer (OCT). Two different observers obtained three repeated measures in two separate sessions. A high correlation was found between the values obtained by the two different observers, except for the thinner layers, epithelium, and Bowman’s layer. Inter-observer analysis showed a high consistency in the measurements obtained by both observers (r 2 ≥ 0.80; p < 0.001) for the thicker layers: CL, stroma, and total cornea. Intra-observer analysis of measurements obtained by each observer within the same session displayed no statistically significant differences between the three repeated measures for both observers (p > 0.05). The present results suggest that manual segmentation of anterior segment OCT images in CL wearers provides acceptable levels of repeatability between observers and between different sessions for the thinner layers, while presenting a high level of repeatability for the thicker layers.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011. Supported in part by research grants to A. Cervino from the Universitat de Valencia (UV-AE-20070225), the "Jose Castillejo" Research Grant from the Spanish Ministry of Science and Technology (JC2008-00078) and the Spanish Network for Research in Optometry (SAF2008-01114-E)

Femtosecond laser technology in corneal refractive surgery: a review.

To discuss current applications and advantages of femtosecond laser technology over traditional manual techniques and related unique complications in corneal refractive surgical procedures, including LASIK flap creation, intracorneal ring segment implantation, astigmatic keratotomy, presbyopic treatments, and intrastromal lenticule procedures. Literature review. From its first clinical use in 2001 for LASIK flap creation, femtosecond lasers have steadily made a place as the dominant flap-making technology worldwide. Newer applications are being evaluated and are increasing in their frequency of use. Femtosecond laser technology is rapidly becoming a heavily utilized tool in corneal refractive surgical procedures due to its reproducibility, safety, precision, and versatility