Docs, could an opthalmoscope with pupil dilated detect an early post viterous detachment easily?

No: Sometimes a posterior vitreous detachment may be partial and can be difficult to detect. Once the vitreous detaches from the nerve it is much easier.

Yes: This requires a skilled examiner - usually an opthalmologist with an MD degree for this type of evaluation. It might require the use of a different type of ophthalmoscope termed an 'indirect ophthalmoscope'.