Background: Recent survey data indicate that some people report long-term improvement in color vision deficiency (CVD), also known as color blindness, following use of psychedelics such as lysergic acid diethylamide (LSD) and psilocybin. However, there are no objective data reported in the medical literature quantifying the degree or duration of CVD improvement associated with psychedelic use.
Case presentation: Here we present the case of a subject with red-green CVD (mild deuteranomalia) who self-administered the Ishihara Test to quantify the degree and duration of CVD improvement following the use of 5g of dried psilocybin mushrooms.
Self-reported Ishihara Test data from the subject revealed partial improvement in CVD peaking at 8 days and persisting for at least 16 days post-psilocybin administration. This improvement may have lasted longer, though the subsequent observations are confounded by additional substance use.
Conclusion: A single use of psilocybin may produce partial improvements in CVD extending beyond the period of acute effect, despite this condition typically resulting from a genetic defect. Systematic exploration of this possible phenomenon is needed to confirm our findings, gauge their generalizability, and determine the mechanism of action.
…Intriguingly, findings from a 2020 study using data from the Global Drug Survey, the largest annual international online survey on drug use (Global Drug Survey 2023), suggest that psychedelics might durably improve CVD symptoms in some people ( et al 2020). In that study, 49% (23⁄47) of respondents with CVD and psychedelic use reported psychedelic-associated symptom amelioration, most commonly after lysergic acid diethylamide (LSD) or psilocybin use. Notably, among respondents reporting this phenomenon, 39% experienced improvements lasting from 3 days to multiple years post-exposure, well beyond the duration of psychedelics’ acute effects…some psychedelic-induced visual effects have been documented in people with non-congenital blindness, though not congenital blindness (Dell’ et al 2018; Krill et al 196361ya). Psychedelics can also enhance color perception, as evidenced by increases in brightness and contrast responses and reports of enhanced saturation and vividness of images (1963; 1962; Kleinman et al 197747ya; 2018). One study also suggests that psychedelics can acutely impair hue discrimination during periods of acute drug effect, with psilocybin exerting this impairment over a wider range of the color spectrum than LSD or mescaline (1963), and this psychedelic-induced impairment might become chronic, as was evidenced in some LSD users (1982).
…The subject was a 35-year-old male with red-green CVD (mild deuteranomalia). Regarding previous psychedelic exposures, he reported use of oral 2C-B (2,5-dimethoxy-4-bromophenethylamine) once, oral MDMA (3,4-methylenedioxymethamphetamine) once, oral psilocybin mushrooms twice, oral LSD 5×, and inhaled DMT (dimethyltryptamine) 7×. After prior episodes of psychedelic use, the subject had noted improvement in color vision persisting possibly for months.
…Just before mushroom ingestion, the subject self-administered the Ishihara Test. Each plate of the test is composed of a mosaic of dots varying in color and size.
…After mushroom self-administration, the subject reported repeatedly self-administering the Ishihara Test starting at ~12 h post-mushroom administration and recorded the results over the next 4 months, at which point he reviewed the answer key for the first time.
…Though the subject reported intensification of colors while under the acute effects of psilocybin, his score on plates 1–21 improved only slightly to 15 at 12 h post-administration. However, by 24 h post-mushroom administration, his score reached 18, above the cut-off of 17 required by the Ishihara Test for classification of normal color vision. His score peaked at 19 on day 8 post-administration. At ~4 months post-mushroom administration, his score remained elevated at 18. The subject’s self-reported scores on plates 1–21 are further detailed in Figure 1. Throughout the 4-month period of observation, the subject continued to smoke cannabis once weekly. He also took a microdose (~10 micrograms) of LSD after recording his test score on post-mushroom administration day 16 and recreationally used an indeterminate amount of nasal esketamine (enantiopure (S)-ketamine) ~two months post-mushroom administration.
…Acknowledgments: We are grateful to our colleague, who wishes to remain anonymous, for designing this self-experiment, gathering the data, sharing it with us, and encouraging us to publish their findings.