First of all, your gf is an imbecile.
Ophthalmoscopy with a handheld ophthalmoscope is once of the most, if not *the* most, clinically difficult examinations to perform. I would not trust the assessment of a medical student's examination on an undilated pupil, as it will likely be horrendously inaccurate.
This is evidenced by the fact she is suggesting you have early glaucoma. Glaucoma cannot be diagnosed by one incidence of ophthalmoscopy. The glaucomatous damage to the nerve cells presents as optic disc cupping, but it is the evolution of these changes (usually against a background of raised intraocular pressure) which provide the diagnosis. Who is to say you don't simply have a large optic disc-to-cup ratio?
Pfft medical students today....useless! (he says only a year removed from medical school himself). You're describing photopsia, the perception of flashing lights. Associated with retinal detachment and posterior detachment of the vitreous. Do you suffer from migraines? If you do, then the aura sensation is a likely culprit. If it isn't, and it is associated with marked visual deterioration, then get yourself to an eye clinic you goddamn idiot and stop asking us for advice.
Otherwise don't worry about it. Everyone has a degree of entoptic phenomenon, it is caused by the perception of blood circulating in the retinal vessels. Unless you have other symptoms (mainly visual loss), then do not worry about it. High blood pressure doesn't usually cause flashing lights btw. It's usually symptomless. Headache in extreme cases (systolic >200), that is about it.
