How Big Is Small?

Abstract

D rs Slavin and Margulis’ reference to “optic discs that are developmentally small” was unsupported by any quantitative measurements or definitions. In one of the largest quantitative studies, the mean disc area was found to be 2.68 mm (range, 0.865.86 mm). Scientific and clinical reports, to have any value, must be precise. Merely stating that a disc is small provides no basis for corroboration or verification. The relative cup-disc ratio, by itself, is also misleading. “One must know the size of the optic disc to evaluate properly the cup-to-disc ratio or neural rim area.” Likewise, no explanation was offered for how Drs Slavin and Margulis determined that the origin of the presumably small discs was developmental. Could it have been the result of a prenatal process? Moreover, the authors apparently did not even acquire the requisite data— axial length, refractive error, keratometric measurements, or retinal images—that might have been used to accurately calculate disc size. Disregard of quantitative considerations is not compatible with clinical activities or scientific publications in the 21st century.