They do look at the back of your eye but it's usually caused by eye injury, or a blood vessel burst. Diabetes causes blood vessel issues on so that's something to encourage you to be proactive with your help.

As you age your risk increases because the jelly in your eye starts to separate from your retina (posterior vitreous detachment) . The first signs of PVD are the lighting flashes and floaters., similar symptoms to retinal detachment. PVD can also increase your risk of the retinal detachment, so that will require follow-ups too.

Fun fact: an opthalmologist is able to see a tumor on the brain during an eye exam. So if they push you to see a doctor after an exam, do it. A friend of the family was diagnosed with brain cancer this way. Opthalmologist said to follow up with his doctor as soon as possible. Then called him the next day to see if he went. He said he'd do it as soon as possible. Then he blew it off. The opthalmologist called his primary care doctor 2 days later and told then to please get him in as soon as possible for an exam. Primary care physician called him to come in and set an appointment whenever he was available day or night. He's still around 5 years later but needed some surgeries and chemo.