Basic Human Neuroanatomy
A Clinically Oriented Atlas 

Case History #47

Date of Consultation: 6-1-1979


This 61-year-old right-handed white male shop owner was referred for neurologic consultation for evaluation of a visual problem in the left eye.  On 5-24-79, the patient noted the acute onset of decreased vision in the inferior aspect of the visual field of his left eye.  He described this as a gray, hazy blank area occupying both inferior quadrants of his left eye only.  He did close the left eye and noted that the vision out of his right eye was entirely normal.  When he closed the right eye, the inferior visual field defect was present.  He denied any other symptoms in the eye including eye pain, foreign body sensation, pain on extraocular movements, diplopia, or other visual field changes.  An ophthalmologist saw the patient and felt that there was papilledema of the optic disc in the left eye.


Mental Status Exam:  Intact.

Cranial Nerves:  Cranial nerve examination was normal except for the following.  Funduscopic examination revealed moderate disc swelling in the left eye with no spontaneous venous pulsations seen.  In the right eye, there was no papilledema present.  Visual field testing revealed full visual fields in the right eye.  In the left eye, there was an inability to perceive objects in the medial (nasal) and lateral (temporal) inferior quadrants.  There was a 2+ afferent pupillary defect (APD) on the left.  Visual acuity was 20/20 in both eyes.  There was no abnormality of external ocular movements or pupillary responses except for the APD.

Motor System:  Intact. 

Reflexes:  Intact. 

Sensory System:  Intact. 

Cerebellar Function:  Intact.

Gait and Stance:  Intact.


1.  Where in the visual pathway would you localize the lesion in this case (optic nerve, optic chiasma, optic tract, optic radiations, or occipital cortex)?

2.  What is an afferent pupillary defect (Marcus Gunn pupil), what is its anatomical basis, and what localizing significance does it have?

3.  What side of the nervous system is involved in this case?  What specific structure(s) is involved by the pathologic process?

4.  In general, what type of pathologic process was involved in this case?

5.  What diagnostic procedure(s) would you undertake at this point?

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