Estimation of normal and glaucomatous optic nerve morphology from perfusion

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Optic nerve head (ONH) morphology is crucial for diagnosing glaucoma.
• Assessing ONH structure typically involves optical coherence tomography (OCT).
• Hemoglobin (Hb) distribution may offer a novel metric for ONH assessment.

Purpose of the Study:

• To estimate optic nerve head morphology using hemoglobin distribution.
• To correlate hemoglobin density with optic nerve tissue thickness.
• To evaluate the potential of hemoglobin measurements for earlier glaucoma detection.

Main Methods:

• Spectralis-OCT and Laguna ONhE application were used on 189 normal and 292 glaucoma eyes.
• Topographic Hb values were correlated with OCT tissue thicknesses.
• Neuroretinal rim volume (RV) and cup volume (CV) were analyzed in relation to globin distribution function (GDF) indices.

Main Results:

• A strong correlation (R=0.953) was found between local Hb density and tissue thickness.
• RV and CV could be estimated from Hb values with high accuracy (R=0.650 to R=0.786).
• RV distribution in a large screening cohort (1,163,241 images) mirrored prospective findings.

Conclusions:

• Optic nerve tissue volume and shape are closely linked to its perfusion.
• Hemoglobin distribution can be used to deduce ONH morphology.
• The relationship between RV and GDF suggests perfusion measurement could advance glaucoma diagnosis to earlier stages.