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A 63-year-old man was referred for an eye exam after a head injury. He reports a collision while playing ice hockey 10 days previously. He complains of bilateral eye pain "like a migraine" and notes more difficulty reading. He denies any loss of consciousness at the time of the injury and subsequent medical examination and head CT scan were normal. His past ocular history is notable for LASIK in 1997 OU. His past medical history is positive for hypertension and high cholesterol for which he is taking oral medications. His BSCVA is 20/15 OD and 20/20 OS; pupillary exam, extraocular motility, confrontation visual fields, and IOP are all normal. Anterior and posterior segment exams are normal except for early cataracts OU.
The patient was reassured that there was no evidence of ocular damage from the head injury and given an updated glasses prescription to sharpen his vision. He was instructed to follow up with his primary doctor if the glasses did not improve his headache/eye pain. Two weeks later, the patient returned complaining that the new glasses did not help and he is still having trouble with his near vision. He says his vision seems to be troublesome for small detail work, specifically, he can't always see small drill holes or the computer cursor. The glasses were checked and found to be correct. On exam, visual acuity with the new glasses measured 20/20 OU and a repeat manifest refraction yielded the same prescription. Amsler grid testing revealed a blurry area at the right portion of the grid OD and was normal OS. Automated perimetry with a Humphrey visual field machine was obtained and showed the following abnormality:
Humphrey visual field OS |
Humphrey visual field OD |
The field tests confirmed a right homonymous inferior quadrantanopia, which was discussed with the patient and his primary care doctor. The original CT scan was rechecked and did not show a lesion; therefore, the patient underwent a brain MRI that revealed an 8 mm enhancing lesion in the left temporal lobe. He is currently undergoing further evaluation of this intracranial mass.
Discussion: This case demonstrates the importance of a detailed history and careful exam as well as the important role of visual fields. Confrontation visual field testing is often not sensitive enough to pick up early or small scotomas, therefore, Amsler grid testing or a more quantitative exam (Humphrey, Goldmann, or tangent screen) is usually necessary. Vague visual complaints in a reliable patient with good central acuity should not be automatically dismissed or labeled functional, rather, they should alert the physician that a more extensive exam may be necessary, and visual field testing is usually the first step.
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