Normal dipotric shifts :
Normal dipotric shifts Most healthy individuals go through several dioptric shifts throughout there lifetime
Birth to age 1-2
Babies are born hyperopic and go through a myopic shift in the process called emmotrpization
7-16 years old
A myopic shift occurs called school myopia
Atributed to the increased time spent accomodated from reading and doing school work
17-25 years
A second myopic shift same as above but called college myopia because most people are in college for this one
40-60 years old
Error drifts towards hyperopia
60+
Error changes towards myopia
Could be due to an increase in the index of the lens
Diabetes :
Diabetes Will cause a fluctuations in dioptric error
Lens swelling
This is most commonly attributed to hyperglycemia causing the lens to swell increasing (-) error
However, the mechanism behind this is poorly understood and several studies have actually suggested just the opposite that hyperglycemia causes a hyperopic shift
Either way diabetes does cause a shift in dioptric power most likely due to swelling of the lens and then the lens returning to normal
Insulin levels
In an animal model it showed that insulin was a a powerful inducer of axial myopia
There is not much information on this
disease :
disease nephropathia epidemica (NE)
Zoonose caused by the Puumala virus
belongs to the group of haemorrhagic fevers with renal syndrome
In the acute phase of the disease it causes forward movement of the anterior diaphragm and thickening of the crystalline lens resulting in a myopic
One proposed mechanism is that the puumala virus multiplies in cappilary endothilial cells which causes increased leakage from these cells which releases osmolar molecules changes in the osmolarity of the aqueous and lens could cause these refractive changes
drugs :
drugs Several drugs are known to cause myopic shifts
Sulfonamides
Topiramate is a sulfa derivative
Acetazolomide
This reaction is idiosyncratic, the mechanism behind it is still contreversial
How is this related to our case? :
How is this related to our case? The lady in our case was taking the drug TOPOMAX which is just another name for topiramate
Topiramate is often prescribed for epilepsy, MIGRAINES, depression, eating disorders, ,bipolar disorders, and trigeminal neuralgia
Side effects of Topiramate are ACUTE ANGLE CLOSURE GLAUCOMA, ACUTE MYOPIA (MYOPIC SHIFT), suprachoroidal effusions, pre-orbital oedema, scleritis, blephorospasm, oculogyric crisis, nystagmus, and diplopia