Quantification of optic nerve head topography in optic neuritis: a pilot study

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Optic neuritis, an inflammatory condition, can lead to significant visual impairment.
• Assessing optic nerve head (ONH) structure is crucial for understanding optic neuritis pathophysiology and prognosis.
• Heidelberg Retina Tomograph-II (HRT-II) offers detailed ONH topography analysis.

Purpose of the Study:

• To compare ONH topography in patients with prior optic neuritis versus healthy controls using HRT-II.
• To investigate the relationship between HRT-II detected ONH changes and visual function (visual acuity, visual field, color vision) and electrophysiology (VEP, PERG).

Main Methods:

• HRT-II imaging was performed on 25 patients with unilateral optic neuritis and 15 controls.
• Patients underwent visual evoked potentials (VEP), pattern electroretinogram (PERG), visual acuity, visual field, and color vision testing.
• Interocular differences in affected versus fellow eyes were analyzed for correlations with functional measures.

Main Results:

• Affected eyes showed reduced mean retinal nerve fibre layer (RNFL) thickness and neuroretinal rim volume compared to fellow eyes (p=0.009 and p=0.04, respectively).
• Affected eyes exhibited an increased 3D optic cup shape measure compared to controls (p=0.01), indicating abnormal cup shape.
• RNFL thickness changes correlated with visual acuity, visual field, and color vision deficits. Color vision deficits also correlated with neuroretinal rim volume reduction.

Conclusions:

• HRT-II detects significant, functionally relevant structural changes in the optic nerve head following optic neuritis.
• Reduced RNFL thickness and neuroretinal rim volume are key HRT-II findings in affected eyes.
• These structural changes are associated with measurable impairments in visual function.