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  • ‘I Didn’t See That Coming!’: 5 Dangerous and Unexpected Diagnoses

    5 Dangerous and Unexpected Diagnoses

    Ophthalmology is a visual specialty. Being able to directly see microscopic pathology within the eye enables us to make diagnoses in our daily practice.

    However, there are times when the pathology we see is not what it seems or when patients present with no or subtle signs. Being able to identify and differentiate these signs and then make the correct diagnoses may allow you to initiate the correct treatment and save your patients’ life and sight.

    Case 1: Left Chronic ‘Conjunctivitis’

    Not all pink eyes are viral conjunctivitis. One patient I saw presented with a three-month history of left-eye redness, which did not improve with topical antibiotic and lubricating drops. There was no known past medical history or history of trauma. On examination, his left eye had a 2-millimeter axial proptosis and slight limitation in movements in all directions of gaze. His left conjunctiva was diffusely injected with dilated and tortuous vessels. Intraocular pressure was 11 mmHg in his right eye and 21 mmHg in his left.

    Computed tomography (CT) angiography revealed a spontaneous left carotid cavernous dural arteriovenous fistula, and the patient underwent embolization by interventional radiology.

    Case 2: ‘My Vision Is Not Better After Cataract Surgery!’

    It is important to look for other causes of blurry vision, especially when the patients’ vision does not correlate with the severity of their cataract or ocular pathology. A 60-year-old male presented with persistent bilateral blurry vision, which did not improve after undergoing bilateral cataract surgeries, despite achieving a postoperative visual acuity of 6/7.5 in both eyes.

    Optical coherence tomography (OCT) of his optic nerve head was unremarkable. However, OCT of his macula ganglion cell layer revealed a binasal pattern of thinning, and his Humphrey visual fields revealed a bitemporal hemianopia.

    MRI revealed a pituitary macroadenoma compressing on his optic chiasm, and he proceeded to have a prompt endonasal transsphenoidal resection of his pituitary tumour.

    Case 3: Steroids Aren’t for Everyone

    Postoperative inflammation can happen for a variety of reasons. Acutely, it is important to rule out toxic anterior segment syndrome and postoperative endophthalmitis. Causes of low-grade inflammation that persists after a month may include premature cessation of topical steroid eye drops, retained lens fragments or uveitis.

    One patient I saw presented 1.5 months after her cataract surgery with left eye redness and blurry vision after stopping her steroid eye drops a week prior. On examination, her left eye had an intraocular pressure of 29 mmHg as well as medium to large granulomatous keratic precipitates with anterior chamber cells 1+ and mild flare. Her intraocular lens was clear, and the dilated fundus examination was unremarkable. We performed an anterior chamber tap, which was positive for cytomegalovirus, and the patient was initiated on ganciclovir and antiglaucoma drops.

    Steroids are essential to manage postoperative inflammation, but they can also lead to the reactivation of viral uveitis. An anterior chamber tap can be diagnostic and help to guide treatment.

    Case 4: Not Your Routine Diabetic

    Retina changes in a person with diabetes may not always be caused by diabetic retinopathy. Hypertensive retinopathy, retina vein occlusions and ocular ischemic syndrome may concurrently present, especially in patients with poorly controlled vascular risk factors.

    I once saw a 60-year-old male patient for routine diabetic retinopathy screening. His visual acuity was 6/7.5 and 6/9 in his right and left eyes, respectively. Fundus examination revealed bilateral scattered Roth spots, in addition to microaneurysms and dot and blot haemorrhages. Preliminary investigations found a high total white  blood cell count. The patient was promptly referred to the internists for further investigations and was later diagnosed with chronic myeloid leukemia.

    Case 5: Beware of the ‘Normal-Looking’ Fundus

    Small signs may herald serious, life-threatening systemic disease. One patient I saw was a male in his 70s with a history of hypertension presenting for a routine eye exam without complaints. His fundus exam was mostly normal. There were no retinal hemorrhages, cotton wool spots or neovascularization — except there was a small refractive embolus in the first bifurcation of the superior-nasal artery in his right eye.

    Urgent carotid ultrasonography revealed an ulcerated right mid-common carotid artery plaque, and the patient was promptly referred to vascular surgery for management.


    Claire Peterson, MBBS, FRCOphthClaire Peterson, MBBS, FRCOphth, is the current Singapore Society of Ophthalmology’s YO Committee chair. Dr. Peterson joined the Academy in 2023.