AIMS To map the thickness, elevation (anterior and posterior corneal surface), and axial curvature of the cornea in normal eyes with the Orbscan corneal topography system. METHODS 94 eyes of 51 normal subjects were investigated using the Orbscan corneal topography system. The anterior and posterior corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, i...

We studied the potential of myopic corneal refractive laser surgery to induce myopia (axial elongation) and potential interactions between aberrations (generally resulting from the procedure) and myopia development in chicks (Gallus domesticus). Ten white Leghorn chicks were monolaterally treated one day post-hatching with photorefractive keratectomy (PRK), with a nominal dioptric change of -9....

BACKGROUND To examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery. METHODS The study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-ker...

PURPOSE To investigate the test-retest variability of and factors associated with the corneal deformation response, and evaluate its impact on IOP measurement. METHODS Forty normal and 140 glaucoma suspect/glaucomatous eyes of 104 individuals were prospectively included for repeated measurements of corneal deformation response by an ultra-high-speed Scheimpflug camera, followed by corneal hys...

PURPOSE To evaluate the theoretical influence of the change in corneal asphericity (ΔQ) on the change in fourth-order Zernike spherical aberration coefficient (ΔC(4)0) with customized aspheric refractive correction of myopia and hyperopia. METHODS The initial anterior corneal surface profile was modeled as a conic section of apical radius of curvature R0 and asphericity Q₀. The postoperative ...

PURPOSE To investigate ocular dimensions in African Americans with the long anterior zonule (LAZ) trait. METHODS A total of 61 African American LAZ subjects and 61 age-matched, race-matched, and sex-matched controls were compared with respect to central corneal thickness, central corneal curvature, axial length (AL), and subjective refraction. RESULTS LAZ right eyes had a mean SR=+1.75±1.82...

Background: Purpose/Aim: To assess ocular parameters in Nepalese children with severe anisometropic amblyopia. Methods: This was a hospital-based cross-sectional analytical study conducted in a tertiary eye center in Nepal. Twentyone children aged 7-12 years with severe anisometropic amblyopia (>3D of anisometropia) were included in the study. Relevant demographic and clinical data were obtaine...

PURPOSE The purpose of the study was to examine the effect of central corneal thickness (CCT), corneal curvature, astigmatism, axial length (AL), and age on measurements with the Pascal Dynamic Contour Tonometer (DCT). METHODS In a prospective clinical trial 75 eyes of 75 patients undergoing phacoemulsification were examined. Before phacoemulsification, the anterior chamber was cannulated at ...

THE normal corneal horizontal diameter is 12 mm. and any value less than 11 mm. is considered to represent the condition of microcornea (Mann, 1958). The term should be applied only to eyes which are normal except for a small cornea. Corneal curvature is increased so that the corneal refraction is usually great, but associated myopia of varying degrees has been observed by Biro (1935), Puglisi-...