الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Keratoconus (KC) is the most common corneal ectatic disorder in which the cornea becomes cone shaped due to significant thinning of the corneal stroma.Visual impairment develops from myopia and irregular astigmatism.
Management of keratoconus varies according to the state of progression of the disease. In very early cases, spectacles may provide adequate visual correction, but rigid gas permeable (RGP) contact lenses provide better correction.
Keratoconus is considered one of the most common indications for penetrating keratoplasty. The development of intra-corneal ring segments has provided a surgical alternative.
Corneal collagen cross-linking (CxL) aims at stabilization of the cornea and arrest the disease progression. However, it does not provide a refractive solution, and visual rehabilitation by glasses or contact lenses will be needed later.
Most patients suitable for CxL as a treatment are young and will require life-long ophthalmic care, so it is important to assess how increased corneal rigidity affects routine ophthalmic examination such as intraocular pressure measurements.
This study was conducted with the aim of evaluating the effect of ultraviolet A corneal cross-linking on the measurement of intraocular pressure. The study was conducted on 50 eyes of keratoconus patients.
The intraocular pressure measured by Goldmann applanation tonometry (IOP GAT) had increased after CxL and this increase was statistically significant (p < 0.001).
Preoperative IOP GAT had a positive correlation with the preoperative Goldmann correlated IOP (IOPg), and the preoperative corneal compensated IOP (IOPcc) measured by Ocular Response Analyser (ORA).
None of the ORA variables (IOPg, IOPCC, CH, and CRF) had a statistically significant change after CxL.
The postoperative IOP GAT had a statistically significant positive correlation with the postoperative IOPg and IOPcc.
from this study we conclude that Cxl had induced a statistically significant increase in IOP GAT, with a statistically insignificant change in the corneal biomechanical properties as measured by CH and CRF.