AIM To understand the effect of the geometric and material properties of the lens on the age-related decline in accommodative amplitude. METHODS Using a non-linear finite-element model, a parametric assessment was carried out to determine the effect of stiffness of the cortex, nucleus, capsule and zonules, and that of thickness of the capsule and lens, on the change in central optical power (...

PURPOSE According to Helmholtz, accommodation is based on the flexibility of the crystalline lens, which decreases with age, causing presbyopia. With femtosecond (fs)-lentotomy treatment, it is possible to restore the flexibility of presbyopic lenses. The efficiency of the treatment can be systematically evaluated using the finite element method based on experimental data. The purpose of this s...

PURPOSE The purpose of this article was to present methods capable of estimating the size and shape of the human eye lens without resorting to phakometry or magnetic resonance imaging (MRI). METHODS Previously published biometry and phakometry data of 66 emmetropic eyes of 66 subjects (age range [18, 63] years, spherical equivalent range [-0.75, +0.75] D) were used to define multiple linear r...

PURPOSE To compare lens dimensions and refractive index distributions in type 1 diabetes and age-matched control groups. METHODS There were 17 participants with type 1 diabetes, consisting of two subgroups (7 young [23 ± 4 years] and 10 older [54 ± 4 years] participants), with 23 controls (13 young, 24 ± 4 years; 10 older, 55 ± 4 years). For each participant, one eye was tested with relaxed a...

PURPOSE The authors have previously shown a marked increase in corneal epithelial arachidonic acid metabolism to 12-hydroxyeicosatetraenoic acid (12-HETE) and 12-hydroxyeicosatrienoic acid (12-HETrE) in a model of closed eye-contact lens wear. Their formation was predominantly cytochrome P450-dependent and significantly correlated with inflammatory score and corneal thickness. In the current st...

PURPOSE To compare ocular biometric parameters in primary angle closure suspects (PACS), primary angle closure glaucoma (PACG) and acute primary angle closure (APAC). METHODS This cross-sectional study was performed on 113 patients including 33 cases of PACS, 45 patients with PACG and 35 subjects with APAC. Central corneal thickness (CCT), axial length (AL), anterior chamber depth (ACD) and l...

Hydrogel (HEMA) contact lenses of increased thickness were worn by owl monkeys (Aotus tivergatus) under open and closed eye conditions to study ultrastructurally the corneal epithelial response to increased stress. The 0.07 mm thick lens with a calculated Dk/L of 4.2-2.2 caused an epithelial thinning without oedema. This thinning was due to a loss of superficial cells and a flattening of the re...

PURPOSE To evaluate changes in anterior corneal topography and higher-order aberrations (HOA) after 14-days of rigid gas-permeable (RGP) contact lens (CL) wear in keratoconus subjects comparing two different fitting approaches. METHODS Thirty-one keratoconus subjects (50 eyes) without previous history of CL wear were recruited for the study. Subjects were randomly fitted to either an apical-t...

Scleral contact lens technology had been applied for several years as part of the treatment of ocular surface diseases, as well as for compensation of corneal surface irregularities. In recent years, new scleral lens designs were developed to compensate for current refractive errors. Becoming more widely used, it is crucial to question the long-term effects of their presence on ocular health. O...

BACKGROUND AND PURPOSE Temporal bone CT is performed frequently in clinical practice. At the same time, the eye lens are exposed to ionizing radiation without any useful diagnostic information delivered. Our aim was to investigate the radiation dose to the lens of the eye by using temporal bone CT scanning with different protocols. MATERIALS AND METHODS Direct axial and coronal CT by using a ...