if it walks like a duck...speak to me about moonblindness and things less sinister...

so, i have an older paint/ wb x gelding- hes approaching 20, we think who has always had a case of the runny eyes in the summer. he wears a fly mask and my barn is as fly free as you can be for a SoCal barn equipped with the death from above fly system and stalls skipped out 3x day. the geldings owner and my staff are VERY compliant with his care when he has needed antibiotics/ eye wash/ clean fly mask.
during our shot clinic i noticed a smallish white "spot" on the retina of one of his eyes. vet stained the lens- to check for a surface lesion- nothing. white spot seems to be small and non dispersed in nature. unaffected by light stimulation. vet was apprehensive about a DX and is referring to hospital.
my glass half empty self goes right to moonblindness but the vet seems hesitant to confirm...
thoughts? what else looks like this? :confused:

An old eye injury that healed as a scar & may be a source of partial blindness.

Moon blindness the whole eye gradually becomes opake and also begins to shrinks.

Uveitis usually presents with squinting, tearing and significant pain. Did your horse act painful when his eyes were tearing in the summer or did he just have tearing? If it was just tearing, I would be inclined to think it was just blocked tear ducts which are nothing major; your vet can easily fix them by flushing the tear ducts. A non-staining white spot on the cornea could be a healed corneal ulcer, sometimes the really small ones can heal without us noticing them.

There are some retinal things that are not necessarily vision threatening. Your situation as reported does not sound like recurrent uveitis..

Leave the Dx to the experts.

I agree with the suggestion to have a vet check the eye, but I will also share this situation. My sister has a 25 year old that has a "spot" on his eye that is not quite white, but not the same color as the rest of his eye. My sister had one of the vets from the clinic that we use take a look and she was told that it was basically an "age spot". It is just an area that lost some pigmentation over the years. He also has runny eyes in the summer, but that is just allergies and usually well controlled with Benadryl.

Have the vet check it out, though. My first horse had recurrent equine uveitis and that is much different from what you are describing. The eye will be very painful and the entire eye will become opaque.