Purpose We compared the anterior segment characteristics of congenital cataract (CC) patients with lens opacities in different locations and proposed a modified, simple CC category system. Methods Cataractous eyes of CC patients were classified into four groups based on the locations of lens opacities shown in slit-lamp examinations and by a 3-dimensional anterior segment imaging system as fo...

To measure the corneal thickness and the depth of the precorneal tear film of contact lens wearers with keratoconus or keratoplasty and to reconfirm the identification and classification of the keratoconus with optical coherence tomography (OCT). The cornea and precorneal tear film of 123 eyes with keratoconus, of 39 eyes after keratoplasty and 8 eyes after LASIK were examined with an OCT (Zeis...

In recent papers (Lowe, I968, I969a) it was shown that in normal eyes, lens position and thickness were coordinated with axial length and radius of corneal curvature, whereas in eyes with primary angle-closure glaucoma these correlations were lacking. Throughout adult life, lenses increase in thickness at the same rate in normal eyes and those with angle-closure glaucoma, but no change could be...

PURPOSE To develop three-surface paraxial schematic eyes with different ages and sexes based on data for 7- and 14-year-old Chinese children from the Anyang Childhood Eye Study. METHODS Six sets of paraxial schematic eyes, including 7-year-old eyes, 7-year-old male eyes, 7-year-old female eyes, 14-year-old eyes, 14-year-old male eyes, and 14-year-old female eyes, were developed. Both refracti...

PURPOSE Symptoms of dry eye are commonly reported in contact lens wearers and are a frequent cause of non-tolerance. The purpose of the present study is to evaluate the effects of oral treatment with particular omega-6 fatty acids in the form of evening primrose oil (EPO) on subjective symptoms, ocular surface signs and tear film characteristic in patients with contact lens associated dry eye. ...

The imaging of the near field by a slab of negative permittivity medium is discussed. The performance of this flat lens is limited by the working wavenumber k0 and the slab thickness d. For k0d 0.937, the resolution of the flat lens can be smaller than the wavelength and depends logarithmically on 1/k0d. The electric field is finite everywhere, but will diverge algebraically as one reduces k0d ...

We investigate the near-field focusing properties of three-dimensional phase antennas consisting of concentric rings designed to have source and image spots separated by several microns from the lens. Tight focal spots are obtained for silicon or gold rings patterned in a silica matrix. We analyze in detail the dependence of the performance of these lenses on geometrical parameters such as the ...

Alvarez and Lohmann lenses are variable focus optical devices based on lateral shifts of two lenses with cubic-type surfaces. I analyzed the optical performance of these types of lenses computing the first order optical properties (applying wavefront refraction and propagation) without the restriction of the thin lens approximation, and the spot diagram using a ray tracing algorithm. I proposed...

It has been noted that patients suffering from long-standing rheumatoid arthritis often display a characteristic corneal lesion. This consists of a partial opacity of the periphery of the cornea involving part or all of its circumference. The cornea in this area is thinned, usually by about a third of its normal thickness and has a well-demarcated central edge. It is minimally vascularized by s...