Overall corneal hydration control expressed as the percent recovery per hour (PRPH) can be assessed with an exponential model that uses data derived from two kinds of corneal thickness measurements; one from monitoring recovery after inducing corneal swelling, and the other from measurements made after the eye has been open long enough to reach its open-eye steady-state (OESS) corneal thickness...

The corneal thickness was measured by pachometry and the corneal endothelium was photographed by specular microscopy in 81 insulin-dependent juvenile diabetic outpatients. The corneal thickness of a normal group, diabetics without and with proliferative retinopathy was (mean +/- SD): 0.527 +/- 0.028, 0.544 +/- 0.028, and 0.566 +/- 0.027 mm, respectively (2p less than 0.01). As revealed in the s...

PURPOSE To assess the biomechanical and keratometric effects and the safety of treatment of progressive keratoconus with UV-riboflavin collagen cross-linking (CXL). METHODS This is a prospective clinical controlled study. Fourteen eyes of 14 patients with progressive keratoconus were treated with CXL after corneal deepithelization. Patients were assessed preoperatively, at week 1 and at month...

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 of volunteers. An ocular response analyzer (ORA...

PURPOSE To investigate the distribution of axial length, anterior chamber depth, lens thickness, vitreous chamber depth, and central corneal thickness in children at different age groups. METHODS We studied 364 eyes in 182 children with ages between 1 and 12 years. Axial length, anterior chamber depth, lens thickness, and vitreous chamber depth were measured by ultrasound biometry. Central co...

An estimate of overall corneal hydration control can be obtained by measuring the rate of thickness recovery following induced corneal swelling; it is expressed as the percent recovery per hour (PRPH). This recovery is nearly, but not exactly, exponential, because there appears to be an initial slower recovery phase lasting about 30-40 minutes. This 30-40 minute period of slower recovery corres...

PURPOSE To evaluate whether the content of ascorbic acid in the corneal epithelium and aqueous humor reflects seasonal fluctuations in parallel with environmental changes. METHODS Reindeer, cattle, rabbits, and humans were examined, to cover a broad spectrum of overlapping habitats. Ascorbic acid was determined by high-performance liquid chromatography. The thickness of the corneal epithelium...

PURPOSE To evaluate factors responsible for the variability between intended and achieved corneal-flap thickness during femtosecond laser-assisted laser in situ keratomileusis (LASIK). METHODS A prospective, nonrandomized, case study was performed on 35 eyes of 18 consecutive patients who underwent LASIK surgery using the 60 kHz femtosecond laser microkeratome. Eyes were assigned to three dif...

THE cutting of corneal lamellae for keratoplasty of a given thickness is laborious and by no means easy in the absence of abundant experience. Some devices for such procedures, such as Bock"s corneal knife, do not permit of sufficient accuracy, and the electric keratotome of Castroviejo is a very costly instrument. The simple and inexpensive device described below enables one to obtain a cornea...