The Bausch & Lomb Keratometer Manual for the Model H-135A, dating to approximately 1928, is a rare original instruction document for one of the most important diagnostic instruments in the history of optometry and ophthalmology. The keratometer — also known as an ophthalmometer — is an instrument used to measure the curvature of the anterior surface of the cornea, a measurement essential for fitting contact lenses, diagnosing astigmatism, planning cataract surgery, and monitoring corneal diseases such as keratoconus.
The Bausch & Lomb Model H-135 was one of the most widely used keratometers in American clinical practice during the early and mid twentieth century, found in optometry offices and ophthalmology clinics across the country. This three-page instruction manual walks the examiner through the proper positioning of the instrument before the patient’s face, the alignment and focusing procedure, and the reading of the corneal curvature measurements from the instrument’s calibrated scale — reflecting the era when such detailed written instructions were essential for clinicians learning to use precision optical instruments without the benefit of video tutorials or manufacturer training representatives.
This downloadable PDF copy preserves a fascinating piece of ophthalmic clinical history, offering insight into both the technical specifications of a landmark instrument and the clinical practice standards of American ophthalmology and optometry in the late 1920s.
