I'm an ophthalmologist. Optometrist are very well educated and very competent. They tend to be better at things optics related like refractions, contact lens fitting, etc. and are perfectly capable of managing bread-and-butter medical ophthalmic issues.

Ophthalmologists tend to be better at complex medical management, especially when there are systemic manifestations and own anything requiring surgical intervention.

Optometrists do a 4-year doctorate. Ophthalmologists do a 4-year MD that includes the full spectrum of medical training (gen surg, ob-gyn, neurology, etc.) and then a 1 + 3 residency that includes 1 year of general medicine or surgery and 3 years of medical and surgical ophthalmology.

There are, of course, optometrists who are very good at medical management and ophthalmologists that are very good at refractive issues (e.g. refractive surgeons). We mostly work cooperatively although things occasionally get spicy. I I enjoy working with and learning from my optometrist colleagues. I go to an optometrist friend when I need a refraction and an ophthalmologist friend for my annual.