normal 0 false false false en-us x-none ar-sa background : the aim of this study was to determine the correlation between corneal hysteresis (ch) and the corneal resistance factor (crf), which are both novel methods of analyzing ocular rigidity/elasticity, and various corneal characteristics, mainly corneal volume in normal subjects. methods : this cross-sectional study included 500 normal eyes...

PURPOSE To evaluate the utility of anterior segment optical coherence tomography (AS-OCT) assessment in the pre- and postsurgical management of full-thickness corneal grafts. METHODS Seventy eyes of 58 patients who had penetrating keratoplasty were included in the study. High resolution AS-OCT scans of the cornea and the anterior segment were performed before and after transplantation in 17 e...

PURPOSE To compare the efficacies of recombinant human collagens types I and III as corneal substitutes for implantation. METHODS Recombinant human collagen (13.7%) type I or III was thoroughly mixed with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. The final homogenous solution was either molded into sheets for in vitro studies or into implants with the appropriate...

OVERVIEW The cornea is a transparent organ with no blood vessels. It covers the iris, pupil, and anterior chamber of the eye. With a refractive power of about +45.00 diopters, the cornea's primary function is the refraction of light rays. Corneal focusing accounts for approximately 70% of the eye's optical power, while the remainder is provided by the lens. When distortions, irregularities, and...

Background: Today corneal crosslinking with ultraviolet-A photoactivation of riboflavin is an established method to halt the progression of keratoconus. In some cases, when the refractive errors are large and the visual acuity is low, conventional corneal crosslinking may not be sufficient. In these cases it would be desirable with a treatment that both halts the progression and also reduces th...

Extensive Descemet membrane detachment (DMD) is a rare complication of intraocular surgery that can lead to corneal decompensation. Although DMD may resolve spontaneously, surgical repair frequently is required. The diagnosis may be difficult because corneal edema can obscure visualization of the Descemet membrane (DM). Ultrasonographic biomicroscopy (UBM) has been the standard for imaging DMD ...

PURPOSE To establish whether average refractive overcorrection or undercorrection of corneal astigmatism based on the orientation (rule) of the astigmatism occurs if toric intraocular lenses (IOLs) are calculated on the basis of anterior corneal measurements in eyes requiring toric IOL cylinder power of 2.50 diopters (D) or greater. METHODS One hundred thirteen consecutive eyes with anterior ...

In vivo corneal light scattering measurements using a novel confocal microscope demonstrated greatly increased backscatter from corneal stromal fibrocytes (keratocytes) in opaque compared to transparent corneal tissue in both humans and rabbits. Additionally, two water-soluble proteins, transketolase (TKT) and aldehyde dehydrogenase class 1 (ALDH1), isolated from rabbit keratocytes showed unexp...

KERATOCONUS: ASYMMETRIC DISEASE Keratoconus is a non-inflammatory corneal ectasia with bilateral involvement in over 90% of patients. However, in a study of 83 patients diagnosed at presentation Burns and coworkers demonstrated there is significant asymmetry of disease both for corneal shape and visual acuity. Quantitative topographical indices reflected changes in corneal power which correlate...