A novel method for determining regional visual acuity in man and its application to a case of macular hole

A novel method is described for measuring the regional visual acuity in the vicinity of the fovea. A letter is flashed for 100 ms in one of nine positions. The size of the letters is increased or decreased systematically until the size of a letter that can be identified correctly in 75% of cases is obtained for each of the nine positions. The method has been applied to the determination of the time course of development of the acuity changes associated with a macular hole in a single case. The relationship of these changes to other changes occurring in the retina or in perception is also described. With appropriate modification the method could be applied to other parts of the retina. Some even simpler tests are also described.