Bumping this thread. I will write more on this later -- for now I want to share a condition called Postural Deficiency Syndrome (PDS) also known as Proprioceptive Dysfunction Syndrome (PDS). Symptoms include pain (migraines, headaches), dizziness, vertigo, eyestrain, sense of being off-balanced. Not all symptoms will appear in all presentations.
Many people are misdiagnosed as having heterophoria and are prescribed prisms or VT and did not get relief. Interestingly, these patients show binocular issues using a Maddox Wing but do NOT have true phorias in the cover test.
The Ophthalmologist who discovered this condition has treated thousands (>300,000) patients with this condition in Lisbon, Portugal, but optometrist who treat this are sparse in the USA.
The treatment is "active prisms" which is VERY different from the prisms typically prescribed in USA. These are oblique prisms (at an angle) and most optical labs don't produce them here. This is sometimes called the. "Dr da Silva protocol" named after Dr. Orlando da Silva.
I am doing research and will wrote more later. Please research and check this condition out.
Dr. Orlando does reply to emails (for free). His website is here. A Facebook group, with Dr. Orlando in it, is here. Please note that English is Dr. Orlando's fourth language.