A patch at the back of the retina that looks yellow because of the carotenoids lutein and zeaxanthin
The macula lutea — the yellow pigments filter blue light
Anatomy · Eye, ear & senses
Macula
The yellow spot at the centre of the retina
Eye · retina, posterior pole
An oval, yellow-pigmented area about 5.5 mm across at the centre of the retina, on the visual axis and just to the temporal side of the optic disc. It is packed with cones and gives the sharp central vision we use for reading, faces and driving; at its middle is a pit, the fovea. It is the target of age-related macular degeneration, a leading cause of central vision loss in older people in the UK.
How to spot them
- ▸A small oval patch at the back of the retina, about 3.5 mm to the temporal side of the optic disc
- ▸Yellow because of the pigments lutein and zeaxanthin (Latin macula lutea, 'yellow spot')
- ▸Contains the fovea, a pit at its centre, and is almost free of blood vessels at the centre
- ▸Damage blots out the middle of the visual field but leaves peripheral vision
What to know
Lies about 3.5 mm to the temporal side of the point where the nerve leaves the eye, on the visual axis
The macula, temporal to the optic disc
Blurring and distortion in the middle of the vision while the edges stay clear; straight lines look wavy on a grid of squares
Macular degeneration, tested with the Amsler grid
Yellow deposits called drusen beneath the retina, a sign of the 'dry' form of a disease of older age
Age-related macular degeneration, affecting the macula
Monthly injections of drugs that block vascular endothelial growth factor, given into the vitreous for 'wet' disease
Anti-VEGF treatment of neovascular AMD in the macula
A small full-thickness defect at the centre of the retina, which shows as a hole on a cross-sectional scan of light waves
A macular hole, seen on optical coherence tomography (OCT)
The region of the retina where the ganglion cell layer is thickest, several cells deep, and cones pack most densely
The macula, responsible for high-acuity central vision
Key ideas
- Because the yellow pigment lies in front of the photoreceptors, it acts as internal sunglasses, absorbing short-wavelength light and improving contrast.
- The macula is only about 2 per cent of retinal area yet takes up a large fraction of the visual cortex, an example of cortical magnification.
Quick-fire facts
- •About 5.5 mm across; its centre is the fovea (about 1.5 mm), and the very middle of that is the foveola (about 0.35 mm)
- •Macula is Latin for 'spot'; lutea means 'yellow'
- •Age-related macular degeneration comes in a dry (atrophic) form, far the commoner, and a wet (neovascular) form that causes most severe sight loss
- •Marc Amsler, a Swiss ophthalmologist, introduced the Amsler grid in 1947
- •Lutein and zeaxanthin come from the diet, notably leafy greens; smoking is the strongest modifiable risk factor for AMD
- •Wet AMD is treated with anti-VEGF drugs such as ranibizumab and aflibercept, given by injection into the eye
- •Stargardt disease is the commonest inherited macular dystrophy, starting in childhood or the teens
- •Optical coherence tomography (OCT) shows the layers of the macula in cross-section
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Sources
- National Eye Institute (NIH) — Age-Related Macular Degeneration (AMD)
- TeachMeAnatomy — The Eyeball — Structure, Vasculature