A recent study published in the Journal of Neuro-Ophthalmology sought to ascertain the causes of optic disc edema (ODE) and the clinical characteristics of patients with ODE presenting to neuro-ophthalmology clinics.
Give me some background.
ODE can stem from a variety of causes that require significantly different workups.
As one of the most common reasons for referral to a neuro-ophthalmologist, it is critical to differentiate between the characteristics of each cause.
Now talk about the study.
In this retrospective study, investigators included consecutive patients with ODE who presented to neuro-ophthalmology clinics over a 5-year period.
The research team reviewed clinical data such as:
- Retinal nerve fiber layer (RNFL) thickness
- Best-corrected visual acuity (BCVA)
- Visual field (VF) mean deviation
- Fundus photography
While analyzing the data, patients were grouped together according to the etiology of ODE.
Talk about the cohort.
In total, 654 ODE patients (mean age 41.2±17.9, 70.6% women) were included in the study.
Of note, female patients (mean age 38.7 years) were significantly younger than male patients (mean age 47.6, P<0.001).
Findings?
The top five most common causes of ODE in neuro-ophthalmology clinics were:
- Idiopathic intracranial hypertension (IIH): 53.7%
- Non-arteritic anterior ischemic optic neuropathy (NAION): 17.4%
- Non-IIH papilledema: 10.9%
- Optic neuritis (ON): 7.0%
- Uveitis: 2.6%
Tell me more.
VA was the worst at presentation in the ON group and the best in the patients with IIH.
Similarly, the Humphrey mean deviation was the worst in the ON/NAION groups and the best in the IIH cohort.
ODE was most severe in patients with non-IIH papilledema and least severe in the ON group.
Note: Humphrey mean deviation refers to the mean elevation or depression of a patient’s VF compared to age-matched controls in a Humphrey VF analysis.
How did IIH and non-IIH papilledema compare?
Interestingly, non-IIH patients with papilledema were not significantly different in VA and VF parameters at presentation compared to patients with IIH papilledema.
Patients with papilledema (both IIH and non-IIH etiologies) had significantly better visual function at presentation compared with the other leading causes of disc edema (P<0.001).
What was the breakdown based on gender?
The top three causes of ODE for female patients were IIH, non-IIH papilledema, and NAION; while in male patients, the top three causes were NAION, IIH, and non-IIH.
Anything else?
The researchers highlighted that papilledema most often presented with bilateral ODE, emphasizing the importance of laterality in discerning between causes of ODE.
Additionally, IIH had a larger proportion of bilateral cases than all other causes of ODE.
Expert opinion?
According to the study authors, “Our results suggest ODE severity can differentiate between etiologies, and a clinician may reasonably suspect optic neuritis and NAION to present with less severe ODE than papilledema.”They added that, “non-IIH papilledema may present with greater ODE.”
Tie it all together for me.
The most common cause of ODE in neuro-ophthalmology clinics was IIH, with these patients more likely to present with preserved visual function.
The higher prevalence of IIH was likely why most patients with ODE were women, according to the authors.
While visual function at presentation could not differentiate the specific cause of papilledema, it was a critical differentiating factor for all papilledema cases compared with all other causes of ODE, including ON and NAION.