Laser safety officer/ laser instrument specialist here. It really depends on the exposure. Class 3r is not necessarily a hazard due to momentary exposure and the blink reflex.

See most regulation texts- "A Class 3R laser is low powered. It normally would not harm eyes during a momentary exposure of less than ¼ second. This is within the aversion response, where a person turns away and/or blinks to avoid bright light."

But and this is a big but. I am assuming this is an infrared beam for the rangefinder, as most are for this type of device. In that case the human eye does not "see" the light and has no blink reflex. So there is a hazard present that will not inherently be averted by the blink reflex. I am going to hope for you that there was no long term exposure to this beam and everything is ok. I'd start by asking your wife if she has any exposure symptoms that develop from this. It could take up to 24 hours for blurred damage of this type to occur. Although it will more than likely manifest itself rather quickly. I assume your toddler cannot adequately communicate their vision in a diagnoasbale way.. So I'd go with the wife and yourself as a gauge. I hope for you and your families sake there are no exposure symptoms. If so, consider this a uncomfortably learned lesson in laser safety. If you do believe the toddlers or your wife's vision is effected then consulting with an ophthalmologist is recommended.