PURPOSE To evaluate with the use of corneal topographic data the differences between total corneal power calculated using ray tracing (TCP) and the Gaussian formula (GEP) in normal eyes, eyes that previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK), and theoretical models. METHODS TCP and GEP using mean instantaneous curvature were calculated over the cen...

BACKGROUND Posterior keratoconus is a rare cause of a corneal opacity in an infant. It is characterized by thinning of the posterior cornea without ectasia of the anterior cornea. Imaging of this condition with anterior segment optical coherence tomography (AS-OCT) has not been reported in the literature. CASE PRESENTATION A six week old African-American male presented with a congenital corne...

Purpose. To assess the amount and the axis orientation of anterior and posterior corneal astigmatism after refractive lenticule extraction (ReLEx) for myopic astigmatism. Methods. We retrospectively examined 53 eyes of 53 consecutive patients (mean age ± standard deviation, 33.2 ± 6.5 years) undergoing ReLEx to correct myopic astigmatism (manifest cylinder = 0.5 diopters (D)). Power vector anal...

In 25 eyes, age range 60-80 years, in purpose of preoperative treatment prior to cataract surgery, measurements of the radius of curvature as well as main meridians of the anterior and posterior corneal surfaces were performed. Average value of the curvature of the anterior corneal surface (R1) was R1 = 7.84 mm, while posterior radius (R2) was 6.4 mm. Main meridian of the anterior corneal surfa...

PURPOSE To evaluate corneal changes after corneal cross-linking (CXL) in progressive keratoconus with Scheimpflug imaging. METHODS This prospective analysis included 40 eyes from 22 patients with progressive keratoconus. Corneal CXL was performed in 25 eyes (CXL group) and 15 fellow eyes served as controls (control group). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), thinne...

Over the past ten years, corneal transplantation surgical techniques have undergone revolutionary changes. Since its inception, traditional full thickness corneal transplantation has been the treatment to restore sight in those limited by corneal disease. Some disadvantages to this approach include a high degree of post-operative astigmatism, lack of predictable refractive outcome, and disturba...

Purpose To compare the corneal clarity measurement between penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) in patients with keratoconus, using densitometry software for the Oculus Pentacam. Methods A retrospective comparative study was carried out at Manchester Royal Eye Hospital. Data were collected 12-18 months after corneal transplantation for keratoconus, incl...

PURPOSE To examine the differences in the biomechanical response of the peripheral regions of the cornea after photorefractive keratectomy (PRK). SETTING Department of Ophthalmology, Catholic University of Rome, Rome, Italy. METHODS Preoperative and 1-, 3-, 6-, and 12-month postoperative corneal topographies of 70 eyes that had PRK with the Technolas 217C excimer laser (Bausch & Lomb) were ...