Gallant, P Modification of Welch-Allyn "11500 ophthalmoscope for visuoscopy. [electronic resource] - Journal of the American Optometric Association Jun 1976 - 748-50 p. digital Publication Type: Journal Article ISSN: 0003-0244 Subjects--Topical Terms: Fixation, OcularHumansOphthalmoscopesRetina