Optic disc evaluation in optic neuropathies: the optic disc assessment project.

Area of Science:

• Ophthalmology
• Neuro-ophthalmology
• Medical Genetics

Background:

• Optic nerve morphology is altered by various genetic and acquired diseases.
• Glaucoma is the most common optic neuropathy, while autosomal-dominant optic atrophy (ADOA) and Leber's hereditary optic neuropathy (LHON) are prevalent hereditary forms.
• These conditions can present with similar optic disc topographical changes, leading to potential misdiagnosis.

Purpose of the Study:

• To evaluate the ability of glaucoma subspecialists and neuro-ophthalmologists to differentiate between glaucoma, ADOA, and LHON based exclusively on optic disc assessment.
• To determine if optic nerve head phenotype alone is sufficient for accurate diagnosis of these optic neuropathies.

Main Methods:

• An observational study involving 23 optic nerve experts.
• Sixty high-resolution stereoscopic optic disc photographs (15 each of ADOA, LHON, glaucoma, and normal controls) were randomized and masked.
• Experts assessed 12 topographic features and provided a presumptive diagnosis, with analysis using the index of qualitative variation and absolute deviation.

Main Results:

• Correct diagnoses were achieved in 85% of normal, 75% of glaucoma, 27% of ADOA, and 16% of LHON cases.
• The accuracy for diagnosing ADOA and LHON was significantly lower than for normal or glaucomatous discs (P<0.001).
• When glaucoma was suspected, 61% were indeed glaucomatous, but 34% were other optic neuropathies.

Conclusions:

• Differentiating between glaucoma and hereditary optic neuropathies like ADOA and LHON based solely on optic disc morphology is difficult, especially in advanced stages.
• Accurate diagnosis necessitates integrating other clinical findings, including visual acuity, color vision, and patient history (visual loss, family history).