From G. S. HOLISTER
It was in the early 1970s that I first discovered the ‘Holister Effect’.
During a visit to the optician’s for an eye checkup I was astonished to
find that, while the optician was inspecting my eyes through his
opthalmascope, for a few moments I saw what, presumably, he was seeing – a
perfect image of my retina. When I asked if any other patients had commented
on this, he said no.
Excited by my discovery I borrowed an opthalmascope and conducted a series
of home experiments. After many attempts I found that by gazing at the
opposite wall while shining the light source into one eye from one side
(about 30 degrees from the axis of my gaze), a position of the light source
could be found which produced a flash of pink light in the illuminated eye
(any small light source worked, the opthalmascope was unnecessary). Holding
this position for a few seconds permitted me to focus on the detailed
structure within the initial blur of pink light: a perfect image of my
retina; sharp black blood vessels standing out in remarkable detail on a
pink background.
First, I assume that the cornea must have a small degree of internal
reflection, probably at its external surface. If so, then when the retina is
illuminated, any point on it will receive a reflected image of a
corresponding point elsewhere on the retina, and vice versa.
I further assume that when one succeeds in focusing on the retinal detail,
the eye lens has adjusted itself to view the reflected image on the
corneal surface. The visual effect is similar to looking out of a window at
twilight and seeing a reflection of the illuminated room as well as the
external view.
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I would appreciate readers’ comments on both the phenomenon and my
explanation of it. If neither the nature of the effect nor my explanation is
refuted then I hereby claim the right to entitle it ‘The Holister Effect’.
G. S. Holister
Buis les Baronnies, France
