What is the ophthalmoscope used for in an eye exam?

[Bellmawr]

When I was having an eye exam yesterday, the doctor used an ophthalmoscope and shined a bright light into my each eye. What can the doctor check by using the a bright light into each eye?

[Bellmead]

The optometrist uses an ophthalmoscope to shine a bright light into each eye in order to examine the retina at the back of the eye. The ophthalmoscope is used for checking the blood vessels and the front of the optic nerve to see whether there are changes caused by some diseases, such as diabetes or high blood pressure.

[Bellmont]

Ophthalmoscopy is done as part of a routine physical or complete eye examination. It is used to detect and evaluate symptoms of retinal detachment or eye diseases such as glaucoma. In patients with headaches, the finding of swollen optic discs, or papilledema, on ophthalmoscopy is a key sign, as this indicates raised intracranial pressure (ICP) which could be due to hydrocephalus, benign intracranial hypertension (aka pseudotumor cerebri) or brain tumor, amongst other conditions. Cupped optic discs are seen in glaucoma. In patients with diabetes mellitus, regular ophthalmoscopic eye examinations (once every 6 months to 1 year) are important to screen for diabetic retinopathy as visual loss due to diabetes can be prevented by retinal laser treatment if retinopathy is spotted early.