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Identifier

000382601

Title

Αξιολόγηση και πρόβλεψη ποιότητας όρασης με χρήση raytracing wavefrontanalysis μετά από ένθεση ενδοκερατοειδικού φακού για τη διόρθωση της πρεσβυωπίας

Alternative Title

Qualification and prediction of quality of vision using ray tracing wavefront analysis after insertion of intracorneal lens for presbyopia correction

Author

Ζουλινάκης, Γεώργιος

Thesis advisor

Παναγοπούλου, Σοφία

Reviewer

Παλλήκαρης, Ιωάννης
Κυμιωνής, Γεώργιος
Τσιλιμπάρης, Μιλτιάδης

Abstract

Summary Time is a river that runs continuously, changing anything that touches, living or nonliving. The human eye could not escape from this river. Thus the time river causes to the eye a condition known as presbyopia. Nobody can escape from this condition and the symptoms afflict the majority of the population over the age of 50 years old. The main symptom of presbyopia is the loss of the focusing ability on nearby targets, in distances less than 1 meter, which makes some tasks that require near vision to become impossible. In this master thesis we studied a group of people (N=40), which has undergone through an intracorneal micro lens (positive lens) incision, which corrects the loss of near focusing ability with the method of monovision. The purpose of this study is to evaluate the quality of vision of patients using ray tracing wavefront analysis and trying to anticipate the postop wavefront result. The insertion of the lens has taken place in the period 2010 - 2011 in the premises of VEIC, in the University of Crete. Patients have undergone repeated examinations at regular intervals until the summer of 2013, when this master thesis was made. Measurements were taken with the iTrace abberometer, from Tracey Technology Corp, as well as clinical refraction measurements. Additionally we developed a code in MatLab, in order to simulate the postoperative wavefront of the patient while knowing the preoperative wavefront and any changes caused by the process of incision, due to digital image processing. We noticed that the monocular uncorrected distance vision of patients decreased by a mean value of 4.4 / 10 postoperatively, while the binocular distance vision decreased by only 0.7 / 10 and the monocular best spectacle corrected distance vision decreased by 2.6 / 10. From the topographic analysis of the anterior corneal surface we noticed that both the insertion process and the lens cause some astigmatism. The induced topographic astigmatism was about 0.67 diopters at 87 degrees, the internal 0.68 to 98 while the total induced astigmatism was 1.1 diopters at 90 degrees. From the abberometry results 8 postoperatively we noticed an increase to coma aberration, especially the horizontal coma, and to the spherical aberration and secondary astigmatism. Furthermore we noticed that the disappointed patients of our group had a greater increase in spherical aberration and coma than our satisfied patients. Regarding the code in MatLab, we were able to apply it to 23 patients, to simulate the postoperative wavefront and correlate it with the real postoperative one. The code had successful correlation (&λτ50% ) in 74 % of our patients. In addition to that, the code can generate images of wavefront and PSF preoperatively and postoperatively as well as expected results, differential wavefront maps and convolutions of the PSF image with vertical grating images to simulate the image that the patient has

Language

Greek

Subject

Intracorneal lens

Presbiopia

Quality of vision

Wavefront

Ενδοκερατοειδικός φακός

Μέτωπο κύματος

Ποιότητα δράσης

Πρεσβυωπία

Issue date