A patient with cone dystrophy empirically discovered that his vision improved when a red filter was placed in front of his eyes. The present study documents the conditions under which his visual acuity and field improved and shows that the patient’s vision is mediated by the night vision photoreceptors, the rods. Increment threshold functions examined the benefits (and limitations) of red glasses to the patient’s vision. (more…)
February 12, 2011
Visual Improvements With Red-Tinted Glasses in a Patient With Cone Dystrophy
Attitudes of Students, Parents, and Teachers Toward Glasses Use in Rural China
Objective To use focus groups to understand barriers to glasses use among children in rural China.
Methods Separate focus groups were conducted between December 17, 2007, and August 5, 2008, for the following 3 groups at each of 3 schools in rural China: children aged 14 to 18 years with myopia of less than –0.5 diopters in both eyes, those children’s parents, and those children’s teachers. Participants were also asked to rank their responses to questions about glasses use. The focus group transcripts were coded independently by 2 investigators using qualitative data management software. (more…)
Through a Yellow Glass Darkly
The patient (A.S.) underwent an uncomplicated cataract extraction on December 27, 2006. The first postoperative visit, exactly 24 hours later, revealed uncorrected visual acuity in the operated eye of 20/15 minus. The surgeon (W.J.S.), by that time tending to his grandchildren in Sarasota, Fla, called with his congratulations.
Six hours later, the patient noted that vision in the operated eye remained clear but that the brightness had declined by several log units and everything was a deep, dark yellow, as if looking through a very dark yellow filter. He nonetheless sat through 2 hours of The History Boys. (more…)
Liquid Crystal Glasses: Feasibility and Safety of a New Modality for Treating Amblyopia
Amblyopia is the most common cause of monocular visual impairment.1-2 Strabismus and anisometropia occurring during childhood are risk factors for amblyopia leading to various levels of poor vision and different responses to currently available treatments.3-5
To overcome the unknown factor of a child’s compliance, avoid the blemish of a mechanical patch, and enhance the child’s willingness to undergo the antiamblyopic regimen, electronically controlled liquid crystal glasses have been developed. Application of a small electric charge changes the spatial orientation of the suspended crystal molecules within the glasses. (more…)
Nonlinear Optical Properties in Bi2O3-B2O3-SiO2 Glasses
Abstract:A series of bismuth borate silica glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical gaps Eopt were obtained from the extrapolation of the linear portions to zero absorption. A decrease in the value of Eopt with increasing bismuth content may be explained by suggesting that the non-bridging oxygen ion content increases .It was found that high refractive index and narrow bandgap could lead into high third-order optical nonlinearity. (more…)
Glasses Tech – Prescription Glasses, Prescription Eyeglasses