Clinical and etiological profile of patients with bitemporal optic disc pallor visiting at a tertiary eye hospital

Bitemporal optic disc pallor may result from chiasmal compression as well as bilateral toxic, nutritional, hereditary, or inflammatory optic neuropathies. Data describing its clinical and etiological profile in Nepal are limited. This study was conducted with the aim to describe the clinical and etiological profile of patients with bitemporal optic disc pallor and to evaluate the relationship between clinical, visual-field, neuroimaging, and OCT findings. A hospital-based prospective, cross-sectional study was conducted among patients with clinically documented bitemporal optic disc pallor presenting to Biratnagar Eye Hospital, Nepal. The minimum calculated sample size was 49, and 50 participants were included in the final analysis. Demographic and clinical findings, Humphrey visual-field patterns, neuroimaging findings, optical coherence tomography-derived retinal nerve fibre layer (RNFL) and macular ganglion cell analysis (GCA) measurements, and relevant blood investigations were evaluated. Data were summarized using frequencies, percentages, means, and standard deviations. The mean age of participants was 38.58 ± 15.20 years, and 58.0% were male. Diminution of vision was the predominant presenting complaint (88.0%). Central scotoma was the most common visual-field defect (48.0%), followed by cecocentral scotoma (26.0%) and bitemporal hemianopia (20.0%). Nutritional optic neuropathy was the most frequent etiology (26.0%), followed by toxic optic neuropathy (20.0%); Leber hereditary optic neuropathy and inflammatory optic neuropathy each accounted for 18.0%. Pituitary macroadenoma was present in 16.0% and Rathke cleft cyst in 2.0%. Bitemporal hemianopia was predominantly associated with sellar lesions. The combined pituitary macroadenoma/Rathke cleft cyst group had the lowest mean RNFL thickness (67.4 ± 10.7 μm). Temporal RNFL thinning was more prominent in toxic optic neuropathy and Leber hereditary optic neuropathy, with mean temporal RNFL values of 39.5 and 40.8 μm, respectively. Bitemporal optic disc pallor demonstrated a diverse etiological spectrum. Sellar lesions were predominantly associated with bitemporal hemianopia and greater overall RNFL loss, whereas non-sellar optic neuropathies were more frequently associated with central or cecocentral scotomas and temporal RNFL thinning. Combined clinical examination, visual-field assessment, neuroimaging, and optical coherence tomography may assist in differentiating the underlying causes.