Differentiating between mild papilledema and pseudopapilledema on fundus photography

OBJECTIVE: True papilledema can be difficult to distinguish from pseudopapilledema, especially if mild. Tele-ophthalmology allows fundus photos of suspected disc edema to be sent remotely to neuro-ophthalmologists for their expert interpretation. This study evaluated the ability of neuro-ophthalmologists to discriminate papilledema from pseudopapilledema in mild cases of optic disc swelling based on fundus photographs, with and without patient information. METHODS: Fundus photographs from 55 patients referred to two neuro-ophthalmology centers for suspicion of papilledema with mild optic disc swelling were reviewed. Patients with normal visual function and no evidence of secondary intracranial hypertension were included. Strict definitions were used to define papilledema and pseudopapilledema. Three neuro-ophthalmologists rated fundus photos as either papilledema or pseudopapilledema before and after the provision of patient age, sex, body mass index (BMI), and visual acuity. RESULTS: Twenty-nine patients fulfilled criteria for the papilledema group and 26 in the pseudopapilledema group. Fifty-one subjects were female, average age was 32.8 years, and average BMI was 30.9 kg/m². When photos were rated in isolation, overall accuracy was 59.4 % and inter-rater reliability was poor (k = 0.052). The true positive rate was 56.3 %, true negative rate 62.8 %, false positive rate 37.2 %, and false negative rate 43.7 %. Providing patient information improved overall accuracy to 64.2 % and inter-rater reliability to k = 0.37. CONCLUSIONS: It is difficult even for neuro-ophthalmologists to correctly distinguish mild papilledema from pseudopapilledema based on fundus photographs alone. Providing basic patient information in telemedicine referrals can improve clinical appraisal and guide the invasiveness of investigations.