Question of the Week

---

A 68-year-old woman presents to your clinic for a cataract evaluation. Her past medical history includes supraventricular tachycardia and inflammatory arthritis. Her current medications include prednisone, methotrexate, estradiol, diltiazem, and Restasis. Her BCVA is 20/40 OD and 20/50 OS. Your slit lamp exam of the external and anterior segment structures is all WNL except for 2+ NS OU. The dilated fundus exam reveals mild bilateral paracentral RPE depigmentation with foveal sparing. You document your finding with fundus photography and decide to refer the patient to one of your retina colleagues before proceeding with cataract surgery.

Based on the history and exam findings for this patient, which of the following tests or additional pieces of information would be MOST helpful to support your suspicions about the cause of the retinal pathology?

A. Amsler grid test

B. History of past infections

C. Color vision testing

D. List of discontinued medications

The answer is D. The patient's fundus exam reveals bilateral paracentral RPE depigmentation with foveal sparing. Given her history of inflammatory arthritis and current medications (prednisone and methotrexate), this presentation is highly suggestive of hydroxychloroquine (Plaquenil) toxicity, which is used for rheumatologic conditions such as Rheumatoid Arthritis, Lupus, and Sjogren’s Syndrome. Although the mechanism of Plaquenil toxicity is not fully understood, we do know that it selectively damages the outer retina including the photoreceptors and RPE while sparing the inner retina. Even though the patient is not currently on the drug, it can cause toxicity even after it has been discontinued, which is why asking for a history of past medications would be important in this case. Although the Amsler grid test and color visual testing (A and C) may be abnormal in the setting of severe Plaquenil toxicity, they are not considered sensitive enough to detect vision loss at early stages. A better choice would have been a 10-2 Humphrey visual field test, which may show a paracentral scotoma. However, this was not an answer choice. Finally, there is sparse literature on retinal infections causing a bull’s eye maculopathy (B).

Source: Eyewiki