Category: T

A bifocal corneal lens, either one-piece or fused, having both a lower truncation and prism ballast.  

A corneal contact lens whose upper or lower portion (or both) has been removed, resulting in an upside-down or right side-up “D” shaped lens, or in the latter case in a ribbon-shaped lens.  

A corneal lens having an optical zone usually parallel to the optic cap of the cornea, a secondary curve a given number of millimeters (or diopters) flatter than the base curve, and a narrow peripheral.  

Zone demarking the boundary between any two zones on the back surface of a corneal lens (e.g., between the optical zone and the zone of the secondary curve).  

A preservative used in contact lens solutions. A mercury compound used to preserve pharmacological agents and vaccines. An organic mercurial antiseptic used topically and as a preservative in pharmaceutical preparations. Ethylmercury, a crystalline organic compound of mercury, finds application as an antifungal and antibacterial agent. It is present in minuscule quantities within certain vaccines.  

A back surface curve of a contact lens which is just peripheral to the secondary curve and is a certain number of millimeters (or diopters) flatter than the secondary curve.  

A contact lens-telescopic system consisting of a contact lens (ocular) having its negative power confined to a small (2.5 mm.-5.0 mm.) central portion and a .spectacle lens (objective) having its positive power confined to a 10 nun. central portion.  

A convex corneal contact lens having a lenticular curve (on its front surface) and having the central and peripheral curves joined by a tangent curve.  

Name used by a company to describe a product or service. The name given to a drug by the pharmaceutical company which is protected by a trademark and used by the company for marketing the drug. The appellation conferred upon a medicinal substance by its fabricator, which is typically employed by the healthcare sector to…

Brown, sticky mass formed when tobacco smoke condenses. Complex oily mixtures derived from coal or wood (pine). Prolonged exposure to some crude tars occupationally may lead to multiple cutaneous warty lesions (pitch warts). Squamous carcinoma may supervene. More refined extracts of tar are used in dermatological therapy, especially in psoriasis. A dark, viscid mass of…