Esther Bang
May 10, 2017 · 3 min read

The Stereoscope in Ophthalmological practice

The stereoscope was a popular device used in the 19th century for mass entertainment that found another application in the field of ophthalmology.(1) This application extracted the idea of the ocular movement being guided and disciplined by the stereoscope. In 1896, a French scientist Louis Émile Javal suggested in his work Manuel du Strabisme, to adapt stereoscopes in the diagnoses and treatment of strabismus, also known as a crossed eyes. Two other scientists shared Javal suggestion: German scientist Edmund Landolt wrote about a similar method in The Refraction and Accommodation of the Eye and Their Anomalies in 1868 and an American doctor, D.W. Wells wrote about it in Steresocopic Treatment of Heterophoria and Heterotropia in 1912.(2) In Wells’ writing, he indicated the use of rectified stereoscopic photographs, images with added graphic marks as seen in figure one.(3)

Figure 1: Showing dots marked on stereograph (Illustrations printed in Dr. Well’s book, Stereoscopic Treatment of Heterophoria and Heterotropia, 1912. New York: EB Meyrowitz)

The domestic Homes-Bates stereoscope found a new place in doctors’ consulting rooms to diagnose and conduct exercises. The ocular movements were dictated by graphic marks that were visible when seen through a stereoscope. These exercises were explicitly prescribed by Javal (1868), Landolt (1886) and Wells (1912).(4)

Before the use of the photographic stereoscopic images, the graphic marks were drawn on blank cards, but the visualization of these marks on the card proved to be very difficult for the patients. Their eyes could not grab the graphic marks and comfortably fix the image. However, the photographic stereograph helped in fixing the stereoscopic gaze enabling the patient to visualize and fix these marks in their gaze.(5)

Other than graphic marks, drawn geometric solids (Figure two and three) were used to induce and hold stereopsis and also to help in detecting suppression.(6)

Figure 2: Stereoscopic Views of Solid Geometry Figures (Card E9. From the Eye Comfort Series, designed by Keystone view, published by Dr. D.W. Wells, no date. Private collection)
Figure 3: Card 14 Designed and published by Keystone view, no date. Private Collection.

Patients with strabismus are incapable of carrying out stereopsis, the visual information that is seen by each eye cannot be fused and thus the brain compensates for this situation by suppressing the information given by one, enabling the information of the other eye to predominate and surface in the mind. When a strabismic patient is examined without a stereoscope, again they will see a single image, like a healthy patient, but a healthy patient will see two separate images when carrying out stereopsis.(7)

These stereoscopic exercise cards also provided a platform for subjectivity to be quantifiable for the first time in the 19th century, through G. Fechner’s experiments of 1860. Science was able to attribute quantitative features through sequence of magnitudes and varying intensities to analyze human perception. The stereoscopic cards lie in a framework that “individualizes bodies by a location that does not give them a fixed position, but distributes them and circulates them in a network of relations.”(8) Fechner’s experiments re-categorized perception and the observer within the realm of “empirical exactitude and technological intervention.”(9) Science had presented a mathematical equation to describe the functional relationship between sensation and stimulus, challenging the position of the observer.(10)

  1. Adams, Gavin. “Duchamp’s Erotic Stereoscopic Exercises.” Anais Do Museu Paulista: Historia E Cultura Material 23.2 (2015): 165–85. Web, 166.
  2. Ibid, 172.
  3. Ibid, 172.
  4. Ibid, 173.
  5. Ibid, 174.
  6. Ibid, 174.
  7. Ibid, 174.
  8. Ibid, 175.
  9. Ibid, 175.
  10. Ibid, 175.