Related Experiment Video
Updated: Aug 2, 2026

Visualizing Visual Adaptation
Published on: April 24, 2017
Antonie Cramer's explanation of accommodation
I den Tonkelaar1, H E Henkes, G K van Leersum
1F.C. Donders Institute of Ophthalmology, Utrecht, The Netherlands.
Abstract:
In the middle of the last century the question of the origin of accommodation was still unsolved. At the suggestion of Donders, Cramer used in 1851 a microscope to demonstrate that accommodation has to be ascribed to an increase in the curvature of the lens. Donders himself had several instruments made for the same purpose. These are still present in the collection of the Royal Netherlands Ophthalmic Hospital.
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