phosphene

Case: 32 years old male is admitted to ICU with acute psychosis. Psychiatry service note reads: "patient having phosphenes."

Answer:

Visual hallucination are common in ICU patients, particularly with underlying mental disease. They can be either formed or unformed. Visual hallucinations may involve lights, colors and shapes.

Simple hallucinations of light are classified as 

• phosphenes, meaning hallucinations of lights without structure, and 
• photopsias, meaning hallucinations of lights with geometric structure such as triangles, diamonds, squares, etc.

#psychiatry

References:

1. Cervetto L, Demontis GC, Gargini C. Cellular mechanisms underlying the pharmacological induction of phosphenes. Br J Pharmacol. 2007 Feb;150(4):383-90. doi: 10.1038/sj.bjp.0706998. Epub 2007 Jan 8. PMID: 17211458; PMCID: PMC2189731.

2. Bókkon I. Phosphene phenomenon: a new concept. Biosystems. 2008 May;92(2):168-74. doi: 10.1016/j.biosystems.2008.02.002. Epub 2008 Feb 16. PMID: 18358594.