Search results
Results from the WOW.Com Content Network
[16] [17] [18] An alternative technique with the phoropter requires the use of a "clock dial" or "sunburst" chart to determine the astigmatic axis and power. [19] [20] Astigmatism may be corrected with eyeglasses, contact lenses, or refractive surgery.
[25] [26] [27] An alternative technique with the phoropter requires the use of a "clock dial" or "sunburst" chart to determine the astigmatic axis and power. [28] [29] A keratometer may also be used to estimate astigmatism by finding the difference in power between the two primary meridians of the cornea.
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 .
Lens clock. A lens clock is a mechanical dial indicator that is used to measure the dioptric power of a lens.It is a specialized version of a spherometer.A lens clock measures the curvature of a surface, but gives the result as an optical power in diopters, assuming the lens is made of a material with a particular refractive index.
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 developed by his professor Franciscus Cornelius Donders .
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
The power could be read right off the dial without having to do mental calculations, the range was far higher, from +19.75 to -28.00 and with cylinders up to 7.50, the battery of cylinders was much more intuitive and easy to use, and it was the first to have Jackson cross cylinders affixed, (the first AO Phoroptors with JCC's were late models ...
AOL Mail welcomes Verizon customers to our safe and delightful email experience!