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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
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Καρυωτάκης, Νίκος
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Thesis advisor
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Παλλήκαρης, Ιωάννης
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Reviewer
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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.
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Language |
Greek |
Subject |
Humour dynamics |
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Outflow facility |
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Rigidity |
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Ευχέρια εκροής |
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Οφθαλμική ακαμψία |
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Υδροδυναμική του υδατοειδούς |
Issue date |
2017-03-29 |
Collection
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School/Department--School of Medicine--Department of Medicine--Doctoral theses
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Type of Work--Doctoral theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/1/2/1/metadata-dlib-1491810204-180247-15831.tkl
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Views |
394 |