Imaging of the eye shows individual differences in the shape of the macula

One of our major research areas is in the field of glaucoma, an eye disease that affects the retinal ganglion cells (nerve cells). These cells are most densely located within the central 10° of the retina from the very centre, the region which is called the macula. Recently there has been an increased interest in the study of the morphology (shape) and functionality of the macula in people suffering from glaucoma, because we expect that this is where the initial pathological changes would appear.

Many researchers have tried to connect functional changes with morphological changes within the central 10° of the retina in people with glaucoma by creating a ‘structure-function map’. In particular, some researchers have included individual anatomical information to improve these maps. For example, at the very centre (foveola), one photoreceptor (the light-sensitive cell of the retina) connects to approximately one retinal ganglion cell, but the connection is slightly displaced spatially. Correcting for this factor would be unnecessary, however, if the maculae of all eyes were equal.

In this paper we explored whether some macular parameters such as the maximum thickness, the minimum thickness and the horizontal distance from the two previous values (we call it “radius”) of high-resolution optical coherence tomography (OCT) scans centered at the foveola are different between individuals. The figure below shows where the scans are centred.

macula-scan

Retinal photo showing where the scans are taken (at the very centre of the retina, the fovea)

foto-paper

The three parameters compared: central thickness, maximum thickness (height) and radius.

We found that the measured foveal shape parameters are different between different people. We also found that the foveal shape is not symmetrical between superior and inferior parts of the retina, which is important because the damage is often asymmetric between the superior and inferior hemiretinae in glaucoma.

This work formed part of Juan Sepulveda’s Masters project. You can read the full published article in Investigative Ophthalmology and Visual Science here.

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