الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
To sum up, this observation cross sectional study of 58 patients concluded that corneal biomechanics is correlated positively with corneal thickness in a strong correlation, and negatively with age, with weak positive correlations with myopia. CH and CRF correlates positively to each other, and they both is correlated positively with corneal curvature (K readings).
The importance of studying corneal biomechanics is rising in the last few decades giving a great benefit to increase the awareness of complications of corneal laser refractive procedures. Measurement of corneal hysteresis assists in predicting which patients have the greatest risk for postoperative ectasia. It helps, in conjunction with corneal topography and pachymetry, in patient selection. It also helps in the type of refractive surgery procedure selection, by specific knowledge of the biomechanical response of the cornea to different procedures.
Moreover, measuring corneal properties in the form of corneal hysteresis and corneal resistance factors aids in characterization of some corneal disorders such as Fuchs’ corneal dystrophy, keratoconus and high myopia which induce lowering of corneal
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biomechanical properties and hence corneal hysteresis, while some other conditions such as diabetes mellitus induces increase in corneal hysteresis by increasing collagen cross linking.
The ocular response analyser is the instrument used to assess the corneal hysteresis and corneal resistance factor. It is based on dynamic bidirectional applanation. It also provides a basis for other important parameters such as Goldmann-correlated intraocular pressure (IOPG) and corneal-compensated intraocular pressure (IOPcc).
We conducted this thesis to study the changes in corneal hysteresis and corneal resistance factor on eyes with myopia in young age group, and to correlate these results with other corneal properties like corneal topography and corneal thickness.
Future studies should be done on the Ocular Response Analyzer Waveform Scoring System and the Keratoconus Match Index (in topography assessment), to examine the validity of detecting abnormal cornea not suitable for laser refractive surgery.
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The corneal hysteresis measured by the Ocular Response Analyzer can be used to detect the biomechanical changes the cornea in various corneal disorders and different degrees of myopic states. We concluded from this study that evaluation of corneal biomechanical properties should take CCT and myopic status into consideration. For more precise and accurate outcomes, we recommend wider scale screening of the corneal parameters in the future studies.
Corneal biomechanics parameters can be used as an adjunct, but not as a sole measure, with other investigations and scoring systems to detect and screen for cornea at risk of ectasia.