The degree of success of treatment, whether medical or surgical, is well known to be dependent on early diagnosis in all fields of medical endeavor. This is particularly true of the chronic forms of glaucoma and has stimulated the development of reliable methods for early diagnosis and for noting the progress of the disease. The importance of careful measurement of the field of vision in these cases has long been recognized. Chronic glaucoma is more dependent on perimetry for its understanding than perhaps any other disease, and many advances in this method of examination have been associated with its study.
The most important addition to the methods of visual field examination has been the introduction of the tangent screen and the use of small test objects for the investigation of the central portion of the field. Many different kinds of screen have been developed varying in size and
MARLOW SB. VISUAL FIELDS IN CHRONIC GLAUCOMATHE EFFECT OF REDUCED ILLUMINATION. Arch Ophthalmol. 1932;7(2):211–223. doi:10.1001/archopht.1932.00820090051004