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To the Editor:
—Captain Field's paper "A Comparison of Ocular Imagery," in the June issue (Arch. Ophth.29:981, 1943), "consists of a comparison of two instruments," the eikonometer and the comparator. Details of the construction and mode of action of the comparator are not given (patents are pending), so that one must confine one's criticism to the results as published. Fortunately, these are ample to demonstrate that the data obtained by the comparator are of no value.The "sensitivity" of each instrument is recorded for 25 subjects with 20/20 vision with or without correction. The refractive corrections are not recorded, nor is the heterophoria as measured by an independent test, such as the cover test or rod test. Fifty readings with the comparator and 52 with the eikonometer are recorded.The sensitivity was of great significance in this as in other experiments. It is what the laboratory workers call
Lancaster WB. EIKONOMETER AND COMPARATOR. Arch Ophthalmol. 1943;30(2):278–279. doi:10.1001/archopht.1943.00880200126019
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