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Identifier 000405749
Title Δυναμική ανάλυση της ενδοφθάλμιας πίεσης για τη μελέτη του ισοζυγίου ροών του υδατοειδούς υγρού στον ανθρώπινο οφθαλμό
Alternative Title Dynamic analysis of intraocular pressure for the investigation of balance flow of aqueous humor in the human eye
Author Καρυωτάκης, Νίκος
Thesis advisor Παλλήκαρης, Ιωάννης
Reviewer Τσιλιμπάρης, Ιωάννης
Δετοράκης, Ευστάθιος
Ταρουδάκης, Μιχάλης
Τσατσάκης, Αριστείδης
Κυμιωνής, Γεώργιος
Παπάζογλου , Δημήτριος
Abstract Puspose: The purpose of this study was the characterization of the relationship between IOP and the outflow facility coefficient of aqueous humor from the eye, using an invasive manometric method in healthy human eye. For each eye the ocular rigidity coefficient was also calculated by appling a novel mathematical method. To carry out the measurements an invasive device was developed - optimized for the recording of IOP and a software was developed for the acquisition and analysis of data. Method: Nineteen patients who undergo surgery cataract were enrolled in this study. For the measurements an intraoperatively device was used and controlled by specially designed software, consisting of micro-stepping pump and pressure sensor. At the beginning of the measurement, the anterior chamber of the eye was cannulated and the IOP was set to 15 mmHg. Subsequently, the IOP was artificially increased from 15 to 40 mmHg, in a stepwise method, by the injection of aqueous solution. After each injection step, the IOP was recorded for a period of 2 sec with a frequency of 200Hz. When the eye IOP reaches 40 mmHg, the infusion stopped and the sensor records for a period of 4 min the decreasing IOP. The coefficient K is calculated from the pressure-volume record in each eye. The outflow facility coefficient C was calculated from the outflow IOP curve decay based on a specially designed mathematical model. This model calculates the pressure - dependent outflow facility coefficient using a method that eliminats errors for non-measurable macroscopic parameters such as the episcleral venous pressure, and the constant pressure – independent outflow, the model includes ocular rigidity and the steady state IOP for each patient. The calculation of outflow facility coefficient for each person was done at five different pressure levels in order to extract its relationship with IOP. Results: The mean ocular rigidity was 0.0283 ± 0.011mL-1. The outflow facility coefficient for the highest IOP value was 0.0672 ± 0.0296 ML / min / mmHg to 40 mmHg, the value of which increased to 0.2652 ± 0.1164 ML / min / mmHg 1 20 at 20 mmHg. The value of R outflow resistance coefficient was respectively 17.9 ± 11.17 min mmHg / ML for IOP 40 mmHg and 4.51 ± 2.69 min mmHg / ML for IOP at 20 mmHg. A significant correlation was found between IOP and the outflow facility coefficient and the outflow resistance coefficient, with the values of the outflow facility coefficient having the lowest value at the highest IOP values.This behavior was evident in all examinees. Post hoc analysis demonstrated a significant statistical difference in outflow facility coefficient and outflow resistance to all IOP levels in which they were calculated (p <0.001).From the analysis of the data, outflow facility proved to have an nonlinear relationship with the IOP. This dependence was described by an exponential mathematical relationship C = C0 e-b * IOP where C0 = 0.9907 ML / min / mmHg and b = 0.069 ML-1.
Language Greek
Subject Humour dynamics
Outflow facility
Rigidity
Ευχέρια εκροής
Οφθαλμική ακαμψία
Υδροδυναμική του υδατοειδούς
Issue date 2017-03-29
Collection   School/Department--School of Medicine--Department of Medicine--Doctoral theses
  Type of Work--Doctoral theses
Permanent Link https://elocus.lib.uoc.gr//dlib/1/2/1/metadata-dlib-1491810204-180247-15831.tkl Bookmark and Share
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