MacKay-Marg tonometer

Historical Significance: This instrument was donated to the Victorian College of Optometry in 1966 for use in the VCO clinic. It was not used for long since optometrists in Victoria obtained legal access to topical anaestehetics in the 1980s and were using them in the late 1960s despite the legal prohhibition. In addition hand held (Perkins) applanation tonometry replaced the Schiotz tonometer that had been used by optometrists in Victoria since the early 1960s diminishing the value of this applanation tonometer. This instrument is an electronic recording applanation tonometer that is sensitive enough that the touch on the cornea does not necessitate corneal anaesthesia. It was devised because at the time optometrists in the USA were not legally able to use corneal anaesthetics and the idea of a tonomerter that did not require corneal anaesthesia was attractive. It was invented by R. Stuart Mackay and Elwin Marg [See R.S. Mackay, E. Marg. Fast, Automatic Ocular Pressure Measurement Based on an Exact Theory Acta Ophthalmologica 37/5, 495-507, 1959. and R.S. Mackay, E. Marg, and R.Oechsli Automatic Tonometer with Exact Theory: Various Biological Applications. Science 131/3412, 1668-1669, 1960.] Marg (1918-) was an optometrist (Berkeley California 1940) who had really wanted to be an electrical engineer. He completed a PhD in Physiological Optics at Berkeley in 1950 and pursued an academic career at Berkeley becoming a full professor in 1962. He researched visual neurophysiology, published widely, but never achieved the recognition his work deserved. See http://brain.berkeley.edu/marg/index.html