I'm a *RETIRED* optometrist, which means my reply does not have any legal standing.
It appears that your problem could possibly be coming from low-grade or 'hidden' inflammation. 'Hidden' in a sense that your doctor might not be able to detect it clinically but it can affect the muscles controlling your focus (ciliary muscles controlling accommodation) so things appear to go "in and out of focus". But also this problem can be coming from the controlling mechanism in the brain, which can also be affected by low-grade brain inflammation. Also, if inflammation affects the optic nerves - the bit that connects your eyes to your brain - it can cause death of neurons or nerve cells that can change appearance of optic discs. If this was the case, the appearance of your optic nerves will change over time. This can only be detected if you get them to monitor your optic nerves in regular basis (e.g. every 6 months), there are number of techniques they can use. There is retinal photography as well as optic never scan. I'm not in US so I don't know how much it will cost, but retinal photo takes two dimensional photos, it's cheap and less reliable vs optic nerve scan can take three dimensional pictures and is more expensive but much more reliable (can detect glaucoma). Like I said, they need to do this over time because if things stay the same over time, it is mostly likely that you're naturally born that way with large C/D ratios (<-- what you referred to "enlarged optic discs"). But if they change over time, that means there is something going on. Also, C/D ratio is fairly similar in both eyes in most people but if one eye looks distinctly different, then it is much more suspicious.
The pressure behind your eyes can be caused by many things, it can be due to elevated eye pressure for instance. If this was the case, your doctor would have picked it up with tonometry (which should be a standard test). It can also be caused by possible low grade optic neuritis, especially if it is throbbing kind.
"Blank areas in visual field when in the dark" sounds like normal blind spots we all have. This will affect center of your vision, whereas peripheral visual field detects will be more noticeable in light during the day.
If I were you, I'd ask the doctor to do tonometry, visual field test and optic nerve scan in both eyes and review in regular intervals. If s/he refuses, find another doctor. If repeated tests reveals nothing and if you continue to have symptoms, ask them to refer you to a neurologist to see if they can find brain inflammation.
Off the top of my head, R-lipoic acid can get into your brain and reduce brain inflammation. So is sulfur containing anti-oxidants such as MSM. Some people are sensitive to sulfur and they commented in this forum that it will make candida worse, but I have found the opposite (obviously, if you know you're allergic, then stay away!). MSM is great detoxifier as well as great anti-inflammatory especially for joints and arthritis.
Other things you can also do is to reduce animal consumption as much as you can, eat organic meat whenever possible, consume as much veges and fruits as you can. If you have not been eating your veges, you might find vit B12 in the form of METHYLcobalamin helpful. Severe deficiency in Vit B12 can cause optic neuritis and 'mysterious' vision loss in some people, although this is rare. It will also help reduce brain inflammation.
For IBS, try turmeric with pepper as an enhancer (since it doesn't get absorbed easily, requires enhancer). Turmeric is also good for joint inflammation. L-glutamine is an amino acid that will help heal the gut linings, which some people find it useful. Another things that can make significant differences are find digestive enzymes and probiotics. It appears that there are many articles about these on this forum. If you suffer from candida, you will find spore forming probiotics such as Lactobacillus Sporogenes (aka Bacillus subtilis, which is found in Treelac etc.) more useful than non-spore forming species. I still recommend that you take many different Acidophilus as well as Bifidus species.
For information on how to reduce inflammation in your body without drugs, I think you might find the following book very helpful. It also has a section on mercury if I remember correctly -
The UltraMind Solution by Dr Mark Hyman
(I'm not affliated with the author in any way)
The lutein and zeaxanthin in the eye formula (the one by Natural factors) will not directly affect focusing or peripheral vision issues. However they are great for retina and would help to some extent to reduce inflammation in the brain indirectly, as they're anti-oxidants that can get into your brain and eyes. But the most important thing is to reduce inflammation in your body overall, I believe that will help with your eyes as well. No amount of coconut oil in the eye(!!) will make any difference, other than making vision more blurry while it is cleared.
Finally, candida can 'upset' immune system and make it prone to inflammatory reaction. So people who have candida need to keep this in mind, they might find anti-inflammatory diet & supplements helpful.
I hope this information helps everyone out there who are having similar problems.
- Hello Kitty -
P.S For some of the supplements mentioned above, I won't list specific brands but you can find them on iherb.com. People who never purchased anything from them before can use the code, HUP647, during checkout to get $5 off their first purchase.