Abstract:
The series of studies comprising this thesis, which assessed more than 1000 laser surgical procedures, was developed to answer a number of key inter-related questions in regard to contemporary corneal refractive and lens surgery.
A novel classification system of normal corneal elevation topography using the Orbscan II topographer was established. These topographic techniques were also used to investigate the comparative accuracy of the Orbscan II topographer compared to A-scan ultrasound in the assessment of anterior chamber depth (ACD), revealing that although mean data for ACD measurement is very similar for the two techniques, the techniques cannot be considered equivalent or interchangeable, with only moderate correlation and a high degree of variability between the techniques in individual subjects.
A prospective study using Orbscan II topography to analyze ablation zone centration in consecutive patients undergoing LASIK for myopia demonstrated that the tracker-assisted Technolas 2l7z appears to produce well-centered ablation zones. Interestingly, decentration of the ablation zone relative to the pupil did not affect post-operative levels of patient satisfaction, perception of visual function, or problems with adverse visual symptoms.
Extensive questionnaire studies assessing aspects of satisfaction and functional improvement in a large cohort of patients undergoing either standard, or wavefront-guided, LASIK for myopia revealed a very high level of satisfaction following both of these procedures.
A large prospective study of 1089 eyes directly assessing the objective outcome of wavefrontguided LASIK and standard LASIK procedures demonstrated that the visual and refractive results of the two techniques are generally very comparable, although notably, significant differences existed between the two treatments in post-operative gain of best spectacle corrected visual acuity (BSCVA), with 15.4% of Zyoptix-treated eyes gaining 2 lines of BSCVA as compared to only 1.4% of Planoscan treated eyes.