The standard intraocular lens (IOL) that is used to replace a cataractous lens cannot change focus from distant to near objects, so most patients need glasses for near vision after cataract surgery. Limited evidence suggests that accommodative IOLs provide better near vision than monofocal IOLs, but not better than multifocal IOLs. Long-term follow-up is needed to confirm patient outcomes, and ...

A 72-year-old man had exchange of a foldable silicone multifocal intraocular lens (IOL) by transection, removal, and monofocal IOL replacement. One month after the exchange, irreversible corneal edema developed and penetrating keratoplasty was performed. At the time of the corneal transplant, a small silicone fragment was discovered in and removed from the anterior chamber. Histologic evaluatio...

PURPOSE To determine the optimal target anisometropia for pseudophakic monovision. METHODS Thirty-five bilaterally pseudophakic patients who received monofocal intraocular lenses were included in the study. Binocular corrected distance visual acuity (CDVA) and binocular distance-corrected near visual acuity (DCNVA) and stereoacuity were measured after simulating 1.00, 1.50, and 2.00 diopters ...

There are many different types of lenses, but largely they fall into the three classes of the title: set-based, delta-based and edit-based lenses. This paper develops some of the general relationships between those classes. The main results are that a category of set-based lenses is a full subcategory of a category of delta-based lenses determined by sending sets to codiscrete categories; that ...

in view of the rapid expansion of contact lens amongst the users, new dimensions have been added to the domain of ophthalmology: giant papillay conjunctivitis, a disease caused by different kinds of contact lens, appears weeks or months after they are used, although some patients are struck years later. the predominant symptoms are increased awareness of lenses, ocular itching, blurred vision a...

purpose: to compare the effect of different deviation measurement techniques and different lens powers on gradient accommodative convergence to accommodation (ac/a) ratio. methods: we randomly selected 78 eligible students of different majors from zahedan university of medical sciences. following retinoscopy for refractive errors, alternate prism cover test, von graefe and maddox rod without ad...

In animal eyes of the camera type longitudinal chromatic aberration causes defocus that is particularly severe in species with short depth of focus. In a variety of vertebrates, multifocal optical systems compensate for longitudinal chromatic aberration by concentric zones of different refractive powers. Since a constricting circular pupil blocks peripheral zones, eyes with multifocal optical s...

In order to increase the water content and the oxygen permeability of hydrogels used in themanufacture of contact lenses, the polar monomer Silicon Hydrogel Contact Lenses (SHCL), and 2-hydroxyethyl methacrylate (HEMA) were copolymerized with the hydrogels. Due to the presence ofpolar monomers in the conventional contact lenses, the major component of the human tear,lysozyme is extensively adso...

This paper elaborates on analysis of progressive spectacle lenses, to correct presbyopia, which are nowadays offered at the market. The paper describes different types of progressive lenses, their parameters, length and width of their progressive segments. It also describes degressive spectacles lenses--progressive lenses on middle and near distance. The main part of the paper is a comparison o...