I think most ODs shy away from pediatric examinations under 5 years old because they don’t feel confident in their retinoscopy skills. In an age where autorefractors are the norm, I would guess some ODs don’t pick up their retinoscope on a regular basis. Personally, I think retinoscopy is the most valuable entrance tests: it’s what you need to do for pediatrics, it helps to confirm pseudomyopia in pre-teen/teens, helps to show odd corneas/cataracts/anything that would otherwise make an OD spin their wheels (waste time) on refraction longer than it needed to be on older patients. Retinoscopy is also a must for any non-verbal patient: stroke, non-verbal autism, etc.
As for 2 year olds, I find them to be easier than 3-4 year olds. The 3-4 year olds can sometimes “fight back” or think that any doctor is bad since they recall getting shots from their PCPs. 2 year olds are more of a clean slate. Having an acuity chart that can play cartoons is a huge game changer. And for BIO/internal views, have the parent put something on their phone that the child likes to watch, and hold that in various positions as you get the views you need.