@alandy233 Your vision problems are strange. I just googled your problems, and here is the AI answer, for what it is worth:

"Why would someone with GCA have vision problems after breakfast?

Someone with Giant Cell Arteritis (GCA) may experience vision problems after breakfast primarily due to jaw claudication, a common symptom where the muscles used for chewing become fatigued and painful due to reduced blood flow. In GCA, inflammation causes narrowing of the blood vessels, including those that supply the jaw and the eye, meaning the act of chewing can trigger ischemia (lack of blood flow) that extends to the optic nerve.

Key reasons for post-breakfast vision problems in GCA patients include:

Jaw Claudication-Induced Ischemia: The exertion of chewing breakfast can cause severe pain in the jaw, tongue, or throat. Because GCA affects arteries in the head, this same restriction in blood flow can cause temporary (transient) vision loss or blurring during or immediately after eating.
Amaurosis Fugax (Transient Vision Loss): Many GCA patients experience "amaurosis fugax"—a temporary, painless loss of vision in one eye, often described as a curtain coming down—before permanent, irreversible vision loss occurs. Chewing breakfast can be a specific trigger for these transient episodes due to the increased metabolic demand for blood in the facial muscles.

Reduced Blood Supply to the Eye: GCA leads to inflammatory narrowing of the ophthalmic artery or its branches, such as the posterior ciliary arteries. If these arteries are already compromised, the demand for blood flow during digestion or the physical act of chewing can cause a temporary drop in blood supply to the eye, resulting in blurry or double vision. "

So maybe there is a lack of blood flow to your eyes caused by these reasons.

You could try splitting your prednisone dose, but I wouldn't do an even split. It is more normal to do 75% - 25%. You could try 50 mg -10 mg or 45 mg - 15 mg.

Also, do you have access to a different doctor? It sounds like you need much better medical advice.