However, brain scans such as by an MRI can help rule out other diseases, such as a stroke or a brain tumor.During EEG, hyperventilation can be used to provoke these seizures. Ambulatory EEG monitoring over 24 hours can quantify the number of seizures per day and their most likely times of occurrence.Absence seizures are brief (usually less than 20 seconds) generalized epileptic seizures of sudden onset and termination. When someone experiences an absence seizure they are often unaware of their episode. Those most susceptible to this are children, and the first episode usually occurs between 4–12 years old. It is very rare that someone older will experience their first absence seizure. Episodes of absence seizures can often be mistaken for inattentiveness when misdiagnosed, and can occur 50–100 times a day. They can be so difficult to detect that some people may go months or years before being given a proper diagnosis. There are no known before or after effects of absence seizures.Absence seizures have two essential components:
Clinical - the impairment of consciousness (absence)
EEG - the EEG shows generalized spike-and-slow wave dischargesAbsence seizures are broadly divided into typical and atypical types: 

Typical absence seizures usually occur in the context of idiopathic generalised epilepsies and an EEG shows fast >2.5 Hz generalised spike-wave discharges. The prefix "typical" is to differentiate them from atypical absences rather than to characterise them as "classical" or characteristic of any particular syndrome.
According to the Glaucoma Research Foundation, "every week of steroid use averaged over a lifetime leads to a 4% increased risk of chronic steroid[-induced] glaucoma".In addition, around 90% of patients with pre-existing open angle glaucoma develop an additional adverse response to steroid treatment. Treatment of uveitic glaucoma
Glaucoma medications, glaucoma surgery and steroids are the primary options for addressing uveitic glaucoma. Approximately 30% of uveitic glaucoma patients require surgical intervention due to insufficient intraocular pressure control while on maximum medicinal therapy.Available surgical interventions to treat the glaucoma in uveitic glaucoma patients pose a high risk to the eye, with a lower success rate compared to glaucoma surgeries in non-uveitic eyes. Steroids for treating uveitic glaucoma patients also carry high risks. Because of the risks inherent in steroid treatment and the ineffectiveness of surgical interventions for uveitic glaucoma, there is currently no approved treatment for uveitic patients who also have glaucoma. A steroid-free medication for uveitis in uveitic glaucoma patients, formulated by Tarsier Pharma, is currently undergoing clinical trials [see Research section]. Challenges related to surgical treatment of uveitic glaucoma
Uveitic glaucoma patients respond poorly to glaucoma surgery; surgery in uveitic glaucoma patients commonly has complications. These complications are caused by either the surgical wound healing improperly or unhealthy levels of pressure inside the eye.Glaucoma surgery usually leads to increased levels of inflammation in the eyes. This is an undesirable consequence, especially in uveitis patients, who already have a high tendency to develop inflammation.