Worried about hospital referral for possible squint and double vision

[Lunchtimehelp]

My child has been complaining of double vision, I took him to the opticians and they said it looks like a squint in one eye. Although it's not obvious when you look at him. He's referred to the urgent eye department at the hospital for further investigation.
He doesn't think it's anything like tumor etc but I'm so worried about it. I don't know much about squints. They need to find out if it's mechanical or neurological. He's eye sight is very good and the eye photos were good too.
I can't help but worry.

I had a squint as a child. When I was five I had an operation to correct it. Perfect vision ever since and I'm now 52. I think it's a much more successful operation now than it was then, so even better

What age is he?
My dd had a squint that I noticed at 18 months old. She was referred to the hospital orthoptist and ended up with glasses as she was long sighted. She also had patching treatment as the sight in one eye was poorer than the other and that helped make the sight more equal.

She was under hospital care until the age of 7/8ish at which point her sight was more stable and we used a local optician instead. She still had glasses and is 22 now

He's 6 years old. I don't know if this is a new thing or he has always had it but only started complaining yesterday of it.

Did the optician do a full eye test?
Has he had an eye test before?

P.s. its very common for that age of child to be referred for hospital eye care so dont worry about that aspect

Yes he did do a full eye test.
He had an eye test last year I think it was.

Did they give a prescription or suggest he's long or short sighted? Squints can often be caused by refraction issues

No, he's got perfect eyesight. Failed the stereo test which is apparently common is you have a squint.