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WhatsTheDx publishes a new Optometry case every day. Five clues, one diagnosis, and no account needed to play.
Play today's Optometry caseFive progressive clues
These are the case findings in their original reveal order, moving from the broader presentation to the most discriminating evidence.
Clue 1
A 24-year-old walks into a Tuesday evening clinic having been hit in the left eye by a squash ball two days ago, under a pair of goggles that had ridden up his forehead. He was fine to drive home afterwards and did not think much of it. What brought him in is that the eye has stayed dim — the way he puts it, the colour has been drained out of that side — and two days on it has not budged. He has never needed spectacles and has no other health problems.
Clue 2
The front of the eye is unremarkable, which is itself worth noting after an injury like this. The cornea is clear, the anterior chamber is quiet with no layered blood, and the lens sits exactly where it should. Pressures are 14 mmHg on the right and 15 mmHg on the left. Both pupils are round and react briskly and equally, and swinging a light between them produces no relative afferent pupillary defect.
Clue 3
The loss is real and it is central. Best-corrected acuity is 6/24 (20/80) in the injured eye against 6/6 (20/20) in the other, and a pinhole does not improve it. On grid testing the middle of the chart is softly blurred, but the lines are not bent or wavy and there is no blank patch with a defined edge. He reports no flashing lights, no new floaters, and no curtain or shadow anywhere in the field.
Clue 4
Dilated examination finds it. The posterior pole of the left eye carries a well-demarcated patch of milky-white clouding that takes in the fovea, and against that pale background the fovea itself stands out as a distinctly redder spot. Indenting the whole periphery turns up no retinal break and no detachment — the retina is flat through 360 degrees, with no subretinal fluid and no blood in the vitreous.
Diagnosis
Commotio Retinae
Why the diagnosis fits
The whole case turns on one question: which layer of the retina is white? Blunt trauma to the eye produces a long list of possibilities, and the examination methodically removes most of them — the cornea is clear, there is no blood in the anterior chamber, the lens has not moved, the pressure is normal, and there is no relative afferent pupillary defect. What is left is a genuine central visual loss, 6/24 against 6/6, with a well-demarcated patch of milky-white clouding at the posterior pole and a fovea that looks redder against it. That redder fovea is worth pausing on, because it is the appearance that sends people towards a retinal arterial occlusion. The separation is anatomical. Arterial occlusion opacifies the inner retina — the ganglion cell and nerve fibre layers — usually produces a relative afferent pupillary defect, and carries a poor visual prognosis. Here the cross-sectional scan shows the opposite pattern: the photoreceptor outer segments and the ellipsoid zone are disrupted, the retina is not thickened, and the inner layers and the pigment epithelium are untouched. The injury sits in the outer retina, which is exactly where blunt trauma deposits it — disrupted photoreceptor outer segments, vacuolisation of the outer retina and oedema in the Henle fibre layer. The other job of the examination is negative and it is the urgent one: indenting the full periphery finds no break, no detachment and no subretinal fluid, so this is not a case that needs a retinal surgeon tonight. The practical consequence is unusual for something that looks this dramatic. There is no treatment to give. Most cases resolve on their own with good visual recovery, sometimes leaving pigmentary change behind, and the honest thing to tell him is that the follow-up scan matters more than anything done today: the integrity of the ellipsoid zone is what correlates with how much vision comes back.
Educational reference
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Open the clinical referenceFor education and entertainment only. This fictional case is not medical advice and does not replace supervised clinical training, diagnosis, or treatment.
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