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Identifier 000421392
Title Αξιολόγηση πρώιμης και ανώτερης οπτικής συμπεριφοράς του φυσιολογικού οφθαλμού μονόφθαλμων ασθενών
Alternative Title Evaluation of visual performance in patients with severe visual impairment in one eye
Author Γιαννακοπούλου, Τρισεύγενη
Thesis advisor Τσιλιμπάρης, Μιλτιάδης
Reviewer Παλλήκαρης, Ιωάννης
Σιγανός, Χαράλαμπος
Δετοράκης, Ευστάθιος
Βελεγράκης, Γεώργιος
Σπανάκη, Κλεάνθη
Σίμος, Παναγιώτης
Abstract Purpose: It is widely accepted that monocular deprivation results in improved visual performance in the non-pathological eye. The current study investigates first the effect of deprivation due to severe impairment in one eye during late childhood or adulthood, on the spatial performance of the fellow “good” eye, and secondly, whether one-eyed patients show any advantages over the binocular vision of normally-sighted individuals under conditions of defocus blur. Methods: Patients with severe visual impairment in one eye (visual acuity equal or worse than count fingers at 1m), for a period longer than 2 years, participated in the study. Only patients with an age less than 50 years and monocular deprivation onset greater than 9 years were included. In Part A, best-corrected contrast sensitivity was evaluated using reversing vertical sinusoidal gratings at 7 spatial frequencies. In Part B, the effect of defocus, induced by positive lenses up to 2.50D, on the pattern reversal Visual Evoked Potential (VEP) and on visual acuity (VA) was measured. Performance of the control group was tested both monocularly (dominant eye) and binocularly. Results: In Part A, binocular viewing of normally-sighted subjects, improved contrast sensitivity by 70% compared to monocular recordings. Average contrast sensitivity in subjects with impaired vision in one eye was found to be higher by 83% compared with the dominant eye of the control group. The increase in sensitivity was independent of spatial frequency. In Part B, VA was always better with binocular than with monocular vision in the control group, with the difference being greater for higher levels of retinal blur. In subjects with one eye average VA was less affected by defocus, similar to the binocular vision of normal controls. The effect of defocus on VEP P100 latency and amplitude in one-eyed patients was similar to the one exhibited in normal under binocular viewing conditions. However statistical significant difference between monocular performance of the two groups was only found for P100 amplitude; the difference in P100 latency did not reach statistical significance. Conclusions: The findings are consistent with growing evidence supporting functional vision changes in patients with severe impairment in one eye, as a result of altered experience in the adult vision system.
Language Greek
Subject Contrast sensitivity
Monocular deprivation
Visual evoked potential
Εναπομείναντας οφθαλμός
Ευαισθησία φωτεινής αντίθεσης
Οπτικά προκλητά δυναμικά
Issue date 2019-03-27
Collection   Faculty/Department--School of Medicine--Department of Medicine--Doctoral theses
  Type of Work--Doctoral theses
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