How might hyperglycemia affect a patient’s prescription?
With hyperglycemia, the lens accumulates sorbitol which in turn pulls water into the lens. This water makes the lens rounder, and causes the eye to become myopic (with images focusing in the vitreous in front of the retina).
It can take a while for this residual myopic affect to recede, so it’s a good idea to make sure that a diabetic’s glucose has been stable for a couple of weeks before prescribing glasses.
Sir, can a hyperopic also become emmetropic due to hyperglycemia
“causes the eye to become myopic” – so yes, a hyperope can become LESS hyperopic (toward emmetropia)
how the refractive surgery affect astigmatism? then how to explain hyperopia with aphakic patient?
If the patient is aphacic, then he/she only has the cornea to refract the light. In the normal eye, the cornea has cca. 43D of refractive power, and the lens 10-20D, depending on accommodation. If you take tehh lens out, the corne alone is not strong enough, to refract the light enough to focus it on the retina. Therefore, it focuses behind the eye –> you have hyperopia.
Refractive surgery – you change the thickness and the surface of the cornea and so correct it’s refractive power. This means, you can also correct astigmatism.