Comparative study of optic nerve head optical coherence tomography in papilledema versus drusen

Background Papilledema can cause permanent visual impairment, while optic nerve head drusen (ONHD) is typically benign. Spectral domain optic coherence tomography (SD-OCT) is essential for differentiating these conditions, providing high-resolution imaging for accurate diagnosis and management. Context Although papilledema and ONHD can present with similar clinical features, they necessitate distinct treatment approaches. OCT serves as a crucial noninvasive imaging modality for distinguishing between the two by analyzing the structural characteristics of the optic nerve head. Aims This study aimed to evaluate the ability of optic nerve head OCT (ONH-OCT) imaging parameters to accurately discriminate the features of papilledema and those of ONHD. Settings and design This cross-sectional comparative study was conducted from August 2023 to July 2024 across multiple ophthalmology centers and hospitals in Assiut and Menoufia governorates, Egypt. Patients and methods The study included 27 patients (51 eyes), divided into two groups: 15 patients (30 eyes) with papilledema and 12 patients (21 eyes) with ONHD. All participants underwent ONH-OCT imaging. Statistical analysis used Data were analyzed using the Statistical Package for the Social Sciences (SPSS), version 25. Normality was assessed using the Shapiro–Wilk test. Comparisons were performed using the χ 2 , Fisher’s exact, t test, and Mann–Whitney U as appropriate. Diagnostic performance was evaluated using the receiver-operating characteristic curve analysis and the Kappa coefficient. A P value less than 0.05 was considered statistically significant. Results The papilledema group exhibited significantly higher peripapillary retinal nerve fiber layer thickness in all quadrants compared with the drusen group. The average retinal nerve fiber layer thickness (RNFLT) was 204.0 μm in papilledema versus 131.4 μm in drusen ( P =0.001), with marked differences noted in the inferior (276.8 vs. 173.9 μm, P =0.003), superior (244.6 vs. 159.0 μm, P =0.007), nasal (168.0 vs. 108.4 μm, P <0.001), and temporal quadrants (126.7 vs. 84.4 μm, P <0.001). Superior total retinal thickness did not differ significantly. Inferior total retinal thickness was elevated in papilledema (676.8 vs. 572.8 μm, P =0.002). Receiver-operating characteristic analysis indicated that nasal RNFLT had the highest diagnostic performance (area under the curve=0.827), followed by temporal RNFLT (area under the curve=0.817). Cutoff analysis showed that a temporal RNFLT of 91 μm showed 83% sensitivity and 71% specificity, whereas nasal RNFLT at 119 μm had 77% sensitivity and 67% specificity. The ONH-OCT parameters did not significantly differentiate mild papilledema from drusen, while advanced papilledema cases demonstrated markedly higher values, with temporal RNFLT achieving up to 85% diagnostic accuracy. Conclusions ONH-OCT plays a critical role in distinguishing advanced papilledema from ONHD, particularly through analysis of RNFLT, with nasal and temporal measurements demonstrating robust diagnostic performance. However, due to the subtle nature of structural changes in mild papilledema, ONH-OCT’s ability to reliably differentiate these early cases from drusen remains limited.