Might glaucoma go undetected in an eye exam?

Yes. : Glaucoma is often silent as you are not able to tell when there is slight damage to the visual field. Furthermore, when eye pressure is an issue, high pressure in the eye, up to about 30, can feel totally normal. No pain, no visual symptoms, or external signs may be present. Only in the late stages does the field constrict to become symptomatic. Prevention is always better so best to get exam.

Not if done properly: An eye examination in an adult should include the measurement of the internal eye pressure and an evaluation of the disc at the back of the eye which is the area targeted by glaucoma. If these have been examined properly then you almost certainly do not have the condition. These determinations are best made by a real doctor: an ophthalmologist.

Yes: Glaucoma is when the optic nerve of the eye (the inside portion) can not withstand the pressure and it slowly dies off (atrophies). During examination they are looking or damage or signs that damage could occur. In the early stages it is possible there is minimal damage and the pressure is/was normal (the pressure can fluctuate from hour to hour). It is possible to not detect if you have it.