Several studies have shown that growth of the primate eye responds in a compensatory direction to both positive and negative spectacle lenses--eyes grow more slowly and become hyperopic in response to positive lenses, and eyes grow more rapidly and become myopic in response to negative lenses. On the other hand, extended wear soft contact lenses, whether positively or negatively powered, induce...

Microorganisms, especially gram-negative bacteria, are considered to play a role in the etiology of certain corneal infiltrative events (CIEs) observed during soft contact lens wear. This study explored the possibility of microbial colonization of soft contact lenses as a risk factor leading to CIEs. In a clinical trial conducted from March 1993 to January 1996, 330 subjects wore disposable sof...

PURPOSE Deprivation of oxygen to the ocular surface during contact lens wear has been implicated in the alteration of sensory function. This study investigates whether increasing oxygen availability through discontinuation of contact lens wear or transfer into highly oxygen transmissible (high Dk/t) lenses leads to a change in corneal or conjunctival sensitivity. METHODS Twenty-seven long-ter...

BACKGROUND Microbial corneal infection is the most serious complication of contact lens wear. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers. METHODS This survey established the incidence of protozoal, bacterial, and fungal contact lens case contamination in 101 asymptomatic daily wear cosmetic contact lens wearers from a domiciliary contact l...

AIMS The corneal epithelial permeability during extended wear of disposable contact lenses was compared with that during daily wear of soft contact lenses. The study was performed to verify whether the extended wear of disposable contact lenses would result in a higher permeability value than the daily wear of soft contact lenses. A higher permeability makes the cornea more vulnerable for bacte...

PURPOSE to evaluate changes in tear metrics and ocular signs induced by six months of silicone-hydrogel contact lens wear and the difference in baseline characteristics between those who successfully continued in contact lens wear compared to those that did not. METHODS Non-invasive Keratograph, Tearscope and fluorescein tear break-up times (TBUTs), tear meniscus height, bulbar and limbal hyp...

Recent technological advances have had a major impact on military aviation. While modern methods of providing visual information via electro-optics/visionics systems have extended the aviator's operational envelope, these devices are becoming increasingly incompatible with spectacle wear. Since close to 22 percent of Army aviators are ametropic (spectacle wearing), alternative means of providin...

Contact lens intolerance in keratoconus may be due to the formation of a proud nebula at or near the apex of the cone. Excimer laser superficial keratectomy was performed as an outpatients with proud nebulae as treatment patients with proud nebulae as treatment for their contact lens intolerance. The mean period of contact lens wear before the development of intolerance was 13.4 years (range 2 ...

Approximately 5% of the world’s population suffer from what is commonly called colour blindness. A small number of products are on the market that claim to improve colour discrimination for colour-blind observers. This study evaluates the performance of a particular product (Colour Correcting lenses) product by performing psychophysical experiments with a colour-blind observer. Without correcti...

PURPOSE To quantify the transmission to ex vivo porcine eyes of Staphylococcus aureus 835 and Pseudomonas aeruginosa 3 from three types of contact lenses-one daily wear and two extended wear-differing in hydrophobicity and roughness. METHODS One daily wear lens (etafilcon) and two extended-wear lenses (one lotrafilcon A and one balafilcon A) were inoculated in a bacterial suspension for 30 mi...