Kowa's 60mm & 66mm spotting scopes can be coupled with any of several eyepieces for your specific needs. There are single magnification models and zooms, and some have apparent viewing angles (real viewing angle multiplied by the magnification factor) of >60°.
Choose an eyepiece with a wide apparent field of view(greater than 60°) if you don't wear thick glasses and want to be "swimming in field". This will provide you with more real field for a given magnification than can ever be had from a zoom eyepiece, allowing easier subject tracking with the benefit of more observable detail thanks to the increase in magnification.
If you have to wear thick glasses, select an eyepiece with long eye relief. These have a profoundly-long distance between the rear element and the location which your pupil can be while still being able to observe the entire field of view. Naturally, this comes at the cost of less apparent field of view, but if you must wear glasses or sunglasses it is the most comfortable option for use.
TSE-14WD 30x Spotting Scope Eyepiece
Push-On Front & Rear Caps
Limited Lifetime Warranty