Establishing Optic Nerve Diameter Threshold Sensitive and Specific for Optic Atrophy Diagnosis.

Area of Science:

• Ophthalmology
• Neurology
• Radiology

Background:

• Optic atrophy (OA) is a condition characterized by vision loss due to optic nerve damage.
• Accurate differentiation between healthy optic nerves and those affected by OA is crucial for diagnosis and management.
• Optic nerve diameter (OND) is a potential imaging biomarker for OA.

Purpose of the Study:

• To establish a threshold OND for distinguishing healthy nerves from those with OA.
• To investigate the correlation between OND in OA and other clinical indicators like RNFL thickness, visual acuity (VA), and visual field mean deviation (VFMD).

Main Methods:

• Retrospective case-control study analyzing MR images of individuals with and without OA.
• OND measured on coronal T2-weighted images at a standardized location posterior to the optic disc.
• Collected data included RNFL thickness, VA, and VFMD for correlation analysis.

Main Results:

• Significantly smaller ONDs were observed in OA patients (mean 1.94 ± 0.32 mm) compared to healthy controls (mean 2.73 ± 0.24 mm; P < 0.001).
• A threshold OND of ≤2.3 mm demonstrated high sensitivity (0.92) and specificity (0.93) for diagnosing OA.
• No significant correlation was found between OND and RNFL thickness, VA, or VFMD in OA patients.

Conclusions:

• Optic nerve diameter is significantly reduced in patients with optic atrophy.
• An OND threshold of ≤2.3 mm is a highly sensitive and specific indicator for OA diagnosis.
• OND measurements did not correlate with RNFL thickness, visual acuity, or visual field mean deviation in this cohort.