Search results
Results From The WOW.Com Content Network
Landolt C. Lea test. logMAR chart. An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. [ 1] Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment.
Specialized screw with a bugle head that is designed to attach drywall to wood or metal studs, but it is a versatile construction fastener with many uses. The diameter of drywall screw threads is larger than the grip diameter. eye screw screw eye vine eye loopheaded screw: screw eye: Screw with a looped head. Larger ones are sometimes called ...
Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula ...
Herman Snellen ( Dutch pronunciation: [ˈɦɛr.mɑn ˈsnɛ.lə (n)], February 19, 1834 – January 18, 1908) was a Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1862). He took over directorship of the Netherlands Hospital for Eye Patients (Nederlandsch Gasthuis voor Ooglijders), after Franciscus Donders.
A shoe using hook-and-loop closures. Hook-and-loop fasteners, hook-and-pile fasteners or touch fasteners (often referred to by the genericized trademark velcro, which was the original name it was given by the inventor), are a method for allowing two surfaces to be repeatedly fastened and unfastened, useful for clothing or other purposes.
Hook-and-eye closure. Hook and eye clasp. A hook-and-eye closure is a simple and secure method of fastening garments together. It consists of a metal hook, commonly wire bent to shape, and an eye (or "eyelet") of the same material into which the hook fits.
Blood loop knot ( dropper loop) – forms a loop which is off to the side of the line. Boa knot – binding knot. Boom hitch – attach a line to a fixed object like a pipe. Bottle sling (jug sling) – used to create a handle for a container with a narrow tapering neck. Bourchier knot – a variety of heraldic knot.
Double hex is a screw drive with a socket shaped as two coaxial offset hex recesses; it can be driven by standard hex key tools. The shape resembles triple square and spline screw drives, but they are incompatible. The radial "height" of each arris is reduced, compared to a six-point, although their number is doubled.