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 said that she had some moderate pain and visual blur which subsided, but then several hours later her vision significantly diminished in this eye. She attributed this to the chemical getting in her eye. She did not seek any care and reported that she felt her vision had improved, despite the fact that she was now 20/400 OD (previously she was 20/20). She now had a prominent relative afferent pupil defect OD. Biomicroscopy was normal and showed no chemical injury. Fundus examination revealed a pale optic disc with attenuated retinal arterioles and optical coherence tomography showed profound retinal thinning. Previous disc photos showed a pink and perfused nerve and normal vasculature.

Based upon her history of sudden, painless vision loss, a pale disc, attenuated retinal vessels, and profound retinal thinning on OCT, she was diagnosed with a central retinal artery occlusion (CRAO). The chemical exposure had no bearing.

The epidemiology of CRAO varies with systemic diseases and risk factors that cause them such as heart disease, cardiovascular disease, giant cell arteritis, smoking, obesity and other chronic or episodic contributors such as bacterial endocarditis. Emboli from various sources travel through the vascular system becoming lodged inside the central retinal artery obstructing the flow of blood to distal tissues.  Calcific emboli are most likely to cause retinal artery occlusion and are often cardiac in origin.  Etiologies related to malfunctioning clotting factors in blood such as antiphospholipid disease, factor VIII abnormality along with protein S and C alteration are also possible etiologies.

In a 46-year-old patient, conditions such as giant cell arteritis, atherosclerosis, hypertension and diabetes are typically not responsible for CRAO and alternate etiologies should be sought. Tamoxifen is a selective estrogen receptor modulator widely used in the treatment of hormone-responsive breast cancer. Tamoxifen has been noted to cause a crystalline retinopathy and should be in the differential of possible causes. However, this patient had a unilateral occurrence and no crystalline maculopathy, thus a direct cause is unlikely.

An association of tamoxifen with large vessel thromboembolic events (especially venous thrombosis) has been established.   CRAO can be caused by inherited or acquired thrombophilia, especially homocysteinemia. Thrombophilia is also caused by exogenous estrogens, estrogen progestin oral contraceptives, clomiphene citrate, and selective estrogen receptor modulators (such as tamoxifen). Additionally, malignancies such as breast cancer create a pro-thrombotic state with an increased risk of thromboembolism.

This patient was in 5-year remission for breast cancer. In the absence of other potential etiologies, it was determined that tamoxifen-associated thrombophilia likely precipitated her CRAO. As the occlusion was over a month old, urgent referral to a stroke unit stroke was not required. Communication was made with the patient’s primary care physician to inform of the retinal vascular event and initiate investigation for a pro-thrombotic state and discuss the possible association with tamoxifen use and prevention of future thrombotic events.

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November 1 – 3, 2019


Click on the toggles below to read previous case challenges.

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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Case Challenge 01 – June 2018

A 27 year old woman presents urgently complaining of painful vision loss in her right eye. She has no known medical history and this has never occurred before. She has an edematous optic nerve with hemorrhaging, an afferent pupil defect, superior arcuate scotoma, pain when she moves her eye, and 20/70 visual acuity. A clear-cut case of optic neuritis possibly as the first manifestation of multiple sclerosis? Perhaps…perhaps not.

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