Question:medium
The photostress test is used to differentiate between which of the following?
The photostress test is used to differentiate between which of the following?
Show Hint
It tests how fast the photoreceptors bounce back after a bright light, so it isolates the layer that holds them.
Updated On: Jun 23, 2026
- Lens and cornea
- Macular and optic nerve diseases
- Cataract and glaucoma
- Retinal and vitreous diseases
Show Solution
The Correct Option is B
Solution and Explanation
Mechanism-first reasoning. The photostress test exploits one simple fact: recovery of vision after a bright bleach depends on the photoreceptors regenerating their visual pigment, and the photoreceptors sit in the macula.
So when a patient has unexplained loss of central vision, you bleach the macula with a penlight for about 10 seconds and time how long it takes to read letters again. If the macula is sick, pigment regeneration drags and the recovery time is long. If instead the problem lies in the optic nerve, the photoreceptors are healthy and recovery time is normal, even though acuity is poor.
That clean split, prolonged recovery in maculopathy versus normal recovery in optic neuropathy, is exactly what the test differentiates. Eliminate the other pairs: it says nothing about lens versus cornea, cataract versus glaucoma, or retina versus vitreous. The answer is macular versus optic nerve disease. Ref: Photostress recovery study, PubMed 836667.
So when a patient has unexplained loss of central vision, you bleach the macula with a penlight for about 10 seconds and time how long it takes to read letters again. If the macula is sick, pigment regeneration drags and the recovery time is long. If instead the problem lies in the optic nerve, the photoreceptors are healthy and recovery time is normal, even though acuity is poor.
That clean split, prolonged recovery in maculopathy versus normal recovery in optic neuropathy, is exactly what the test differentiates. Eliminate the other pairs: it says nothing about lens versus cornea, cataract versus glaucoma, or retina versus vitreous. The answer is macular versus optic nerve disease. Ref: Photostress recovery study, PubMed 836667.
Was this answer helpful?
0
