A burn of the cornea (the clear front surface of the eye) by ultraviolet B rays (UVB). Also called radiation keratitis or photokeratitis.
The condition typically occurs at high altitudes on highly reflective snow fields or, less often, with a solar eclipse. Artificial sources of UVB can also cause snowblindness. These sources include suntanning beds, a welder’s arc (flash burn, welder’s flash, or arc eye), carbon arcs, photographic flood lamps, lightning, electric sparks, and halogen desk lamps.
Symptoms include tearing, pain, redness, swollen eyelids, headache, a gritty feeling in the eyes, halos around lights, hazy vision, and temporary loss of vision. These symptoms may not appear until 6-12 hours after the UBV exposure.
Treatment consists mainly of keeping the eye closed with patches, after instilling a few drops of ophthalmic antibiotic solution, such as sulfacetamide sodium 10% with methylcellulose or gentamicin. Vision usually returns after 18 hours. The surface of the cornea usually regenerates in 24 to 48 hours.
Prevention involves sunglasses with adequate UVB protection and full coverage of the eyes (side shields).
- Snowmobile safety
The recreational operation of snowmobiles by persons younger than 16 years is NOT recommended. Snowmobiles should NEVER be used to tow persons on a tube, tire, sled, or saucer. A graduated licensing program is advised for ALL snowmobilers 16 years and older (just as is required in many states in the US for automobile drivers).
A change in which a single base in the DNA differs from the usual base at that position. These single base changes are called SNPs or “snips.” Millions of SNP’s have been cataloged in the human genome. Some SNPs such that which causes sickle cell are responsible for disease. Other SNPs are normal variations in […]
Tobacco in the form of a powder that is inhaled into the nose, not smoked. Snuff and chewing tobacco are the two main forms of smokeless tobacco in use in the United States. Cancers of the oral cavity (i.e., the mouth, lip, and tongue) have been associated with the use of chewing tobacco as well […]
- Snuffbox, anatomical
A hollow seen on the radial aspect (the thumbside) of the dorsum (the back) of the wrist when the thumb is extended fully. The reason that it is called the anatomical snuffbox is that snuff (powdered tobacco) could be put there and then inhaled.
- Social anxiety disorder
Excessive fear of embarrassment in social situations that is extremely intrusive and can have debilitating effects on personal and professional relationships. Also called social phobia. Phobias are persistent, irrational fears of certain objects or situations. They recognize that their fear may be excessive or unreasonable, but are unable to overcome it. The symptoms and signs […]