Case Challenge 11 – July 2019

A 57 year old asymptomatic woman was referred for a glaucoma evaluation due to elevated intraocular pressure (IOP). Her visual acuity was 20/20 in each eye and pupils were normal without afferent defect. Her IOP was 25 mm Hg OD and 24 mm Hg OS. Her optic nerves were symmetrically cupped at 0.6/0.6 OD and 0.7/0.7 OS with no evidence of rim thinning, pallor, focal rim defects, hemorrhage, or retinal nerve fiber layer (RNFL) defects. Additionally she passed color vision screening in each eye. Optic coherence tomography revealed a robust and normal RNFL and ganglion cell analysis in each eye. However, threshold perimetry presented unexpected results: Her left visual field was perfectly normal, but her right had a complete left nasal hemianopic defect exquisitely respecting the vertical midline.

Such findings should prompt an investigation for a neurologic, non-glaucomatous etiology. Confounding was the fact that the field defect was only present in her right eye with normal results in her left. Chiasmal and retrochiasmal causes virtually always have bilateral visual field defects respecting the vertical midline which assist with lesion localization. Unilateral visual field loss localizes to an etiology anterior to the chiasm. However, every aspect of her anterior visual pathway including acuity, pupils, color perception, RNFL and optic disc were all normal. So, where is the problem occurring?

Chiasmal and retrochiasmal lesions are expected to have bilateral visual field loss. If the lesion occurs at the chiasm, the defect will be bitemporal. Lesions posterior to the chiasm will present with hemianopic defects occurring on the side opposite the lesion. The more posterior the lesion, the more congruous the visual field defect. A left superior quadrantanopsia would indicate a right temporal lobe lesion and a left inferior quadrantanopsia localizes to the right parietal lobe. Visual field loss occurring in one eye only indicates an issue anterior to the chiasm. However, such issues rarely, if ever, respect the vertical midline as seen here. Additionally, such lesions will also present with some readily identifiable abnormality in visual acuity, color perception, afferent pupillary response, optic disc health, or RNFL structure. This woman had no such findings.

When faced with a situation that shouldn’t exist, alternate explanations should be sought. In this case, no advanced neuroimaging was needed to ascertain the cause. After a brief discussion, it was determined that the perimetrist who administered the test did not choose the proper words when instructing the patient (who had never previously taken a visual field test). Instead of telling the patient that she was going to test the right eye first, the perimetrist instead said that she was going to test the right side first. Thus, the patient was under the impression that she should ignore all stimuli presented in her left visual field, which she did exquisitely well. Fortunately, the patient didn’t do the same thing when testing the left eye, otherwise she would have likely undergone a lot of unnecessary testing. Repeat perimetry with proper instruction resulted in a perfectly normal visual field in each eye as well as a few laughs.

Always remember that a patient can fake vision loss, but they can’t fake a pupil defect or RNFL abnormality.

Attend & Earn 15-20 COPE Continuing Education Hours


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February 14-16, 2020

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Nashville, TN
November 1 – 3, 2019


Click on the toggles below to read previous case challenges.

Case Challenge 10 – May 2019

A 46-year-old woman presented for a scheduled IOP check and visual field as a glaucoma suspect. She had a history of breast cancer 5 years earlier and was using tamoxifen. She reported that she got some cleaning fluid in her right eye 4 weeks earlier. She...

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Case Challenge 09 – April 2019

An 84-year-old African-American man with a history of glaucoma presented for consultation and care. Review of past records indicated that he had also been diagnosed the previous year with dry age-related macular degeneration (AMD) OD and wet AMD...

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Case Challenge 08 – March 2019

A 53 year old man who had been treated for advanced glaucoma presented with slowly progressive, painless vision loss in his right eye. He had missed his visits for the past year, though he had been obtaining medication refills through his pharmacy. His...

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Case Challenge 07 – January 2019

A 25 year old woman was involved in a minor automobile accident where she was hit by another driver. The accident was reportedly minor, with no initial injury to either driver, and both cars were able to be driven away. She felt that she experienced only a...

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Case Challenge 06 – November 2018

Optometric Education Consultants Clinical Case Challenge A 21 year old male plumber called in requesting an urgent appointment. He was working on a job and trying to dislodge a drain coupling by hammering it with the blunt end of a screw driver. He missed,...

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Case Challenge 05, Explained – October 2018

  A 47-year-old man presented complaining of gradually decreasing vision and monocular diplopia in his right eye for approximately the past 18 months. He had undergone LASIK vision correction over 13 years earlier with an excellent...

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Case Challenge 05 – September 2018

A 65 year old woman previously diagnosed with primary open angle glaucoma presented for ongoing care. She was using latanoprost in each eye and had bilateral selective laser trabeculoplasty performed two years earlier. Her medical history was significant for hypertension, elevated cholesterol, and arthritis.  Her vision was 20/20 OD and 20/25 OS. She had an inferior retinal nerve fiber layer defect in the right eye and significant superior rim damage in the left eye. Threshold perimetry showed the above corresponding visual field defects.

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Case Challenge 04 – August 2018

The first patient is a 16 year old male whose vision has been fluctuating for 6 weeks. He also complains about headaches. His primary care physician feels it’s a normal growth spurt and Mom feels it’s migraines as there is a strong family history, but she still wants eyes checked. His vision is 20/20 OD/OS uncorrected and he has bilateral optic disc edema.

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Case Challenge 03 – July 2018

A 35 year old man presents wanting another opinion due to “blood on my right eye”. He says that everything happened 3 days ago after violently vomiting, reportedly due to food poisoning from chicken Caesar salad. He still feels a little nauseated and somewhat “not himself”. He saw another practitioner 3 days ago, was told he had a ‘bruise’ on his eye and it should go away in 1-2 weeks. From the outward appearance, he seems to simply have just a subconjunctival hemorrhage…or does he?

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Case Challenge 02 – June 2018

A 13 year old female was referred for painless reduced vision (20/40) in her left eye with a concurrent abnormal screening visual field, reportedly elevated intraocular pressure (IOP), and an afferent pupillary defect. Her previous exam was 3 weeks earlier and she had been previously referred to an ophthalmologist over a year earlier by another optometrist, but her mother did not know why and did not take her. When presented with painless vision loss in a young patient with these findings, there are numerous diagnostic possibilities.

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