[3] Before the first known human cases, some tests were done rearing animals in darkness, to deny them vision for months or years, then discover what they see when given light.
Described by "Chesselden": When he first saw, he was so far from making any judgment of distances, that he thought all object whatever touched his eyes (as he expressed it) as what he felt did his skin, and thought no object so agreeable as those which were smooth and regular, though he could form no judgment of their shape, or guess what it was in any object that was pleasing to him: he knew not the shape of anything, nor any one thing from another, however different in shape or magnitude; but upon being told what things were, whose form he knew before from feeling, he would carefully observe, that he might know them again;[6] Unfortunately, Dolins was never able to see well enough to read, and there is no evidence that the surgery improved Dolins' vision at any point prior to his death at age 30.
[1] A total of 66 early cases of patients who underwent cataract operations were reviewed by Marius von Senden in his German 1932 book, which was later translated into English under the title Space and sight.
[7] In this book, von Senden argues that shapes, sizes, lengths and distances are difficult for blind people to judge, including for a time after their operation.
In his book, An Anthropologist On Mars (1995), neurologist Oliver Sacks recounts the story of Virgil, a man who saw very little until having cataract surgery at age 50.
In a similar analogy between vision and sightless (touch-only) experience, Bradford was able to visually read the time on the ward clock just after his operation.
[9][10][11] Michael G. "Mike" May (born 1954) was blinded by a chemical explosion at the age of 3 but regained partial vision in 2000, at 46, after corneal transplantation and a pioneering stem cell procedure by San Francisco ophthalmologist Daniel Goodman.
Hannan (2006) hypothesized that the temporal visual cortex uses prior memory and experiences to make sense of shapes, colours and forms.
At three years of age, May's vision had still not reached the acuity of an adult person, so his brain was still not completely exposed to all possible clarity of images and light of the environment.
This study proposed that Michael's long-term blindness affects his ability to distinguish in between faces of males and females, and to recognize pictures and images.
Cohen et al. (1997) proposed that in their early age, blinded subjects developed strong motivations to tactile discrimination tasks.
In 2006, journalist Robert Kurson wrote a book on May, Crashing Through, expanded from an article he did for Esquire,[13] which was adapted into a motion picture.
[15] More recently, another condition called aniridia has been treated with reconstructive surgery using the membrane from the amniotic sac that surrounds a fetus combined with stem cell transplantation into the eye.
Each patient wore spectacles with miniature video cameras that transmitted signals to a 4-mm-by-5-mm retinal implant via a wireless receiver embedded behind the ear.