Question: What is “pinholing” a patient?
Answer: The pinhole can be used when checking vision. A pinhole changes the eye from a lens focussing system into a pinhole camera … thus removing a lot of potential refractive error by removing the misaligned rays of light. If a patient’s vision improves when looking through a pinhole, then the patient may be using the wrong glasses.
People see better when squinting because their eyelashes turn into multiple “pinholes.”
Comments and Feedback
1 Comment
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Sir, How much spherical refractive error can a pin hole correct if the pin hole is placed at a vertex distance of 12mm.
Comment by Anant V. Lakhotia — November 19, 2011 @ 9:49 am
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