It had been many years since I had last seen Don, one of my favourite college lecturers, so I was delighted to bump into him at a conference. Back in the old college days he had been something of a Sean Connery look-alike and was much admired by the girl students, so it was a shock to see him now carrying a white stick and being accompanied by a (rather attractive) girl helper. He informed me that he had recently become registered as blind, yet it was apparent that he could still see to a limited extent. He explained that he had some usable peripheral eyesight but that his central area of vision was seriously affected; it transpired that he was suffering from "macular degeneration." I had never heard of the condition, so we found a place to sit and talk and he set about repairing my ignorance – and in the process he introduced me to a weird area of human experience that I had no idea existed.

The Dying of the Light

I learned that macular degeneration is a disease that damages the central portion of the retina known as the "macula." This area deals with what is called "fine acuity vision" used in "straight ahead" visual tasks such as reading, writing, driving, watching television, sewing, and similar activities. The disease produces what is in effect the opposite of tunnel vision. It can occur in two different forms, known as "wet" and "dry," and though there is as yet no cure for either there are some preventative procedures available in cases where the condition has not progressed too far. Macular degeneration in one eye usually indicates that the other will soon become similarly afflicted. Incidence of the disease becomes more prevalent with age, though it can occur earlier in life, and its first symptoms are easily missed – they are literally overlooked. (Having hypochondriacal tendencies, I made a mental note while Don was talking to have a check-up with my eye doctor within the week.)

With Don the disease had reached a fairly advanced stage and he explained to me how he could no longer read or write as before, or even type. This was because both letters and numbers would vanish suddenly from his sight and then reappear, disrupting any attempt at protracted reading or writing. This still occurred even when he used large print or magnifying glasses, though he had found that leaning down towards a page while wearing a jeweler's loupe enabled him to read and write adequately for short and simple tasks such as writing checks.

I praised Don for the calm, measured way in which he was dealing with his disability – a particularly distressing one for someone like him who so valued books. He smiled and shrugged, saying it was a matter of getting on with an unavoidable situation. "But it is the visions that take some getting used to," he muttered, his voice suddenly taking on a darker tone.

Blindsided by Visions

"Visions? What do you mean, Don?" I asked, totally nonplussed. He outlined several forms of hallucination that were plaguing him. The first one to manifest was what Don described as looking like "a ball of string or basketwork, a globular shape with an aperture on one side." He would see this image as if projected onto walls or other surfaces. He could sometimes make out a small face inside the aperture, and on the occasions this became particularly evident the basket-like effect would adjust around it like a bizarre head-dress. A similar effect was the occurrence of a "pool of pale grey light" which would often appear a few yards in front of him when he was walking along. Faces would also appear within this strange pool of light.

Don explained to me that these visual effects were developing into more complex imagery. When seated at breakfast and looking out of his window into the garden he had on several occasions seen a kind of illumination within which not just one but a number of figures appeared, walking in a column. They were seemingly all male, some wearing hats, others caps. They would silently advance towards the window then turn to the right near the garden shed, but one figure would often break away from the others at this point and come right up to the window as if peering in at Don before it too moved out of sight to one side.

I learned that an even more startling version of this type of vision had occurred shortly before our meeting. When Don was visiting the graveyard where his wife is buried he sat for a while on a bench. He suddenly saw one end of the church on the far side of the cemetery become illuminated. Then there appeared "great crowds of figures" of both sexes and in all manner of dress moving in a stately way towards the church – this time they were not advancing towards him. They entered the large area of illumination and vanished.

A further visual effect which Don considered to be "rather spectacular" was the disappearance of people in front of him, especially presenters on stage in lecture situations. First the person's head would vanish and then the torso, yet Don would be able to see the background behind where the now invisible figure was standing with perfect, uninterrupted clarity.

I asked Don if he was in a normal state of consciousness when he had all these odd visions and he confirmed that he was. Moreover, he had been talking to another sufferer of macular degeneration who quietly admitted that he, too, was seeing curious visions. I promised my old tutor that I would research the subject to see what if anything could be found out about these bizarre visual effects.


Enter Charles Bonnet

I read a paper on macular degeneration but it failed to mention anything about visions or hallucinations, so I asked a neuroscientist friend about the matter. He replied at once saying that the effect in visually impaired people was known to medical specialists as the "Charles Bonnet Syndrome." He directed me to some references on it.

Charles Bonnet was an eighteenth-century Swiss philosopher who was the first person to describe the presence of visual hallucinations in psychologically normal people when he noticed his grandfather who was blinded by cataracts claiming to see birds and buildings that were not there. It was thought to be a fairly rare condition until as recently as the 1980s when research indicated that its incidence was in fact moderately widespread in elderly and visually handicapped people. One factor that had held up the full appreciation of the situation was that people experiencing the visions were often unwilling to mention them to anyone, especially their doctors, in case they were judged to be going insane.

The research reveals that the hallucinations can last from a few seconds to several hours and can be of many things, both familiar and unfamiliar to the person viewing them. Hallucinatory content can include inanimate objects, people, animals, plants and bunches of flowers, trees, and complete scenes. Some people see strange things such as monsters, shining angels, or transparent figures floating in a ghostly manner through rooms and hallways. A small percentage of reported cases involve visions of recently deceased people who had been known to the patient. Although most of the content of the hallucinations are life-size, there are also reports of visions of miniature people – for example, one person saw two tiny policemen putting a midget villain into a diminutive prison van! The hallucinated objects can float in the air, but more typically they merge with the physical surroundings – so a visionary person might be seen sitting in a physically real armchair. In a few instances a person's whole surroundings can become visually altered, and rooms or even streets can seem to change their shape making it difficult for the person to get around; one extreme case of this in the literature involved a man who when approaching the top of a flight of stairs had the vision of being on top of a mountain, rendering his descent of the staircase somewhat difficult. Another case study recorded in the literature reminded me of Don's experiences: a retired lawyer saw people dressed in soldier-like uniforms putting on street parties outside his house. They were always very busy, he said.


Picture This

The Charles Bonnet Syndrome is merely an observation, not an explanation, so what exactly causes these hallucinations? On that subject the medical literature becomes less helpful, and it is clear, even admitted, that no one really knows. I could buy the idea that patches of light in the central visual region could be related to pathological conditions in the macula, and could cause people and writing to apparently disappear intermittently, but faces at the window, and people dressed in various costumes walking toward churches or driving vehicles or holding street parties seem more of a stretch. This was especially the case for me in that I was also aware that people claiming to encounter spirits, whether psychic mediums or ordinary individuals in spontaneous cases, tend to report seeing them in their peripheral vision rather than directly, "head on." I could not help but wonder with these macular degeneration visions whether we were dealing with hallucinations or spirits or some subtle level of perception between them both.

Although the actual mechanics are currently unknown, the basic official theory explaining the visions associated with visual impairment like macular degeneration is that the brain, on receiving incomplete visual data through the eyes, "fills in" the missing elements as best it can – a kind of "best fit" process. In fact, there is evidence that it is only the input of a constant visual stream through our eyes that prevents the brain making up its own imagery in any case. This has been demonstrated in sensory deprivation experiments in which subjects who are placed in total blackout conditions for long periods experience hallucinatory imagery to lighten their darkness. All of us experience this in another form and to a lesser degree when we dream.

If this explanation is true, then a whole host of other implications are raised. If animated figures in costumes, shades of the dead, processions leading to physically real churches, whole landscapes and entire, complex scenes can be rendered in intricate detail by the brain struggling to "fill in" gaps in sensory data, what then is "reality"? Could what we take to be concrete materiality be a kind of hallucination sustained by cultural conditioning, and are paranormal phenomena simply glitches in that illusion? Are the different, spirit-based worldviews held by tribal societies simply other forms of hallucination no less "real" than our own? Is the Hindu doctrine of apparent reality being but the "Veil of Maya," of illusion, correct?

Whatever the answers are to such questions, one thing is certain – we do not see with our eyes alone.

Photo credit: image by dejay181 under Creative Commons license