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6 August
Phosphenes — the experience of seeing light without light actually entering the eye. From the Greek phōs (light) and phainein (to show). What I'm seeing is my own visual system: the retina and visual cortex are never fully silent, and phosphenes are that spontaneous or mechanically-provoked activity perceived as if it were light. The classic ways they arise: • Spontaneously in darkness or with closed eyes — random retinal cell firing and "dark noise" that the brain renders as faint rings, blobs, or drifting patterns. This is closest to mine: they're often called closed-eye visuals, and the slow morphing over time is characteristic, because the underlying neural activity keeps shifting. • Pressure phosphenes — rub or press the closed eyes and geometric blooms appear; mechanical pressure activates retinal cells directly. Documented at least as far back as the ancient Greeks. • After bright light — though if I've just looked at something bright, the lingering shape is technically an afterimage (photoreceptor fatigue), not a phosphene. The morning case — eyes open briefly, then closed — likely sits between the two: part afterimage of the bright scene, part phosphene activity as the visual system settles. What makes them interesting for this project: they're an image with no external referent whatsoever. There is no object to check against — the only access is observation with closed eyes, held in memory. "From memory" is load-bearing here, and philosophically sharper than in ordinary drawing-from-memory: everyone else's "from memory" refers to something once seen in the world; this refers to something that was never in the world. A strangely universal-yet-private image — everyone has phosphenes, but nobody can compare them side by side. Threads to follow: the ophthalmologist Jan Purkyně catalogued and drew his own phosphene patterns in the 1810s — observational drawings of an unobservable subject. Phosphene-like geometry (rings, lattices, spirals) recurs in art across cultures. And the ring is also Christie-Coxon's signature motif — a hinge between the private phenomenon and an existing painting practice. ———————————————————————————————— TO READ — Purkyně's dissertation (1819), in Wade, Brožek & Hoskovec, "Purkinje's Vision: The Dawning of Neuroscience" (2001). Sections, in this order: §XXIV "Luminous Rings" (p.94) — start here. My phenomenon, described in 1819. Rings at the edge of the visual field, and: "These rings... appear at the entry point of the optic nerve most vividly after waking in the morning." Rings. On waking. He notes they aren't static — they respond to whether the eye is focused near or far. His own drawing of them is there (Fig. 29): concentric rings with irregular edges. §XXVIII "Persisting Images, Imagination, and Visual Memory" (p.100) — the "from memory" problem, worked out two centuries early. A hard distinction to borrow: a memory image is held by an act of will, disappears when attention slackens, can be voluntarily recalled, and keeps its position in space as the body moves. An afterimage floats involuntarily, sits in the eye, follows its movements, and only ever represents surfaces. I'm working with the first kind. §I–III "Light and Shade Figures" / "Pressure Figures" (pp.64–70) — the classic phosphene experiments; his most reproduced drawings. §VII "Spontaneous Spots of Light in the Visual Field" (p.77) — closed-eye visuals with no provocation at all. Then for context: ch.3 (pp.38–60), the editors' historical background, laid out section-by-section to mirror the dissertation — read a section of Purkyně, then its companion. Ch.5 "Assessment" (p.104) for what he got right. Skip for now: accommodation, strabismus, vertigo (ch.1) and the biography (ch.2). The method is the point: he treated his own subjective visual experience as legitimate observational data, and drew it because there was no other way to record it. When I draw the morning ring I'm not inventing a method — I'm joining one.