The client's presentation is characteristic of conversion disorder, also known as Functional Neurological Symptom Disorder. This condition involves neurological symptoms, such as blindness, paralysis, or numbness, that cannot be explained by a medical evaluation or neurological condition. The onset of these symptoms is often associated with significant psychological stress or trauma, representing an unconscious "conversion" of emotional distress into a physical symptom. The diagnostic findings of no organic cause for the blindness, coupled with a history of recent trauma, strongly support this diagnosis.

A. Delusion: This is a fixed, false belief (a disturbance in thought content), not a physical sensory symptom like blindness.

B. Illusion: This is a misinterpretation of a real external sensory stimulus, such as seeing a shadow and thinking it is a person.

C. Hallucination: This is a false sensory perception without any real external stimulus, such as hearing voices when no one is present.

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). As cited in: Tollefson, J., & Bishop, L. (2021). Psychiatric-Mental Health Nursing: Foundational Concepts. University of West Florida Pressbooks. Chapter 10, "Somatic Symptom and Related Disorders," Section on Functional Neurological Symptom Disorder (Conversion Disorder). (This university courseware explains that the disorder involves one or more symptoms of altered voluntary motor or sensory function, with clinical findings showing incompatibility between the symptom and recognized neurological or medical conditions).

2. Aybek, S., & Perez, D. L. (2022). The clinical evaluation of functional neurological disorder. JAMA Neurology, 79(2), 203–212. https://doi.org/10.1001/jamaneurol.2021.4598 (This peer-reviewed article discusses the diagnostic criteria, emphasizing the essential rule-out of neurological disease and the frequent association with psychological stressors. See "Clinical Evaluation" section).

3. Reeves, R. R., & Ros-Rull, G. (2018). Differentiating Somatic Symptom Disorder, Functional Neurological Symptom Disorder, and Malingering. The Journal of the American Academy of Psychiatry and the Law, 46(3), 386–389. https://doi.org/10.29158/JAAPL.003781-18 (This publication clarifies the distinction between conversion disorder and other conditions, highlighting the lack of an organic basis for the neurological symptom).