Hi
@Ace Redford, Lack of sleep makes everything worse!! My thoughts as a TID, not professional opinion or advice.
So stress might cause some sleep disturbance, the sleep disturbance might then cause fractiousness and more stress and perhaps more reliance on caffeine which also affects sleep, and alcohol which creates further problems.
With stress, the body releases cortisol, a stress management hormone which makes insulin less effective and which tends to mobilise body stores like stored glucose from the liver a very "anti-insulin' action.
As others have said fluctuating BSLs (and 170 mg/dl is above normal and just one reading) can affect vision - the lens of the eye swells due to the increased level of glucose in the body.
But I have heard of mothers stressed by lack of sleep who have had temporary but severe visual disturbance. And eye doctors do at times diagnose people as having spasm of the eye muscles due to stress alone.
Poor diet with lack of Vitamin A affects vision too.
It seems to me that unless your fiancee's stressful situation is alleviated her vision, stamina, coping levels and diabetes may have great difficulty in improving.
I am uncertain where you live and thus what support services might exist ? visiting mothercraft nurse ? counselling services ? social work services, support from relatives etc.
Certainly adjustment of diet and insulin are likely necessary and perhaps a visit to the doctor, both to discuss her visual problems, diabetes and stress. Her child may also have some condition making him/her more difficult to settle, feed etc.
In such circumstances we as diabetics are advised
to not have new glasses dispensed as the visual difficulty is likely to change with reduction of stress etc.
Best Wishes and please keep posting. A worry shared is a worry halved.