Monocular simultaneous refraction.

A system was developed to give an alternative to the standard Jackson Cross Cylinder test. This system eliminates the major difficulty of the Jackson Cross Cylinder test, which is alternative viewing of the images. The advantages of this system are: 1) ease of patient choice, 2) speed of testing, 3) patient preference, and 4) ease of understanding the test. The major disadvantage of this test system was that a few patients had difficulty viewing two images. Most difficulties could be easily resolved by a variation in the examination technique. (It helped if the patients were told they would now see double, or two rows of letters.) Occasionally, patients who had a field loss found this test difficult. The second problem was similar to one encountered with the Jackson Cross Cylinder test in that some patients would report one target clearer, regardless how one changed the lens. This was overcome by turning the testing lens system over so that the testing lens on the bottom was now on the top. Recently, we have relied only on the MSR technique as our subjective refraction, and the final prescription was based on it. These patients have reported no problems and have had good acuities. The MSR technique, when tested on a large number of patients, is demonstrated to be both efficient and reliable. The simultaneous refraction technique is not meant to be used to the exclusion of all other cylinder subjective tests, but, rather as an adjunct to our standard technique when conditions warrant its use.