Overview

Diameter≈5.5 mm (≈18°)

Distance from disc centre≈3–4 mm temporal

PigmentsLutein and zeaxanthin

The macula is the region of the posterior retina bounded by the temporal vascular arcades, ≈5.5 mm in diameter (≈18° of visual field), centred ≈3–4 mm temporal and slightly inferior to the optic disc. Histologically it is defined by a ganglion cell layer more than one cell thick. Its yellow colour comes from the xanthophyll carotenoids lutein and zeaxanthin concentrated in the inner retinal layers, which filter blue light (reducing chromatic aberration and photo-oxidative damage).

The macula is subdivided concentrically into the foveola (≈0.35 mm), fovea (≈1.5 mm), parafovea (ring ≈0.5 mm wide) and perifovea (ring ≈1.5 mm wide). Although it is only ≈4% of the retinal area it provides nearly all detailed central vision — reading, recognising faces, driving — and is represented by a disproportionately large area of the visual cortex (cortical magnification).

Macular function is tested by visual acuity, the Amsler grid (distortion, scotoma), colour vision and optical coherence tomography (OCT), which images the retinal layers in cross-section.

Location: Posterior pole of the retina, ≈3–4 mm temporal to the optic disc, between the superior and inferior temporal vascular arcades.

Parts & subdivisions

Fovea
Central depression ≈1.5 mm wide where inner layers are displaced and cones are most dense.
Parafovea and perifovea
Surrounding rings with the thickest ganglion cell layer (up to 7–8 cells thick).
Macular pigment
Lutein and zeaxanthin (dietary carotenoids) — blue-light filter and antioxidant.

Anatomy

Arterial supply: Inner layers: branches of the central retinal artery (temporal arcades) ± cilioretinal artery. Outer layers and fovea: choriocapillaris.

Function

Central, high-acuity vision
Colour discrimination
Fixation and reading

Clinical significance

Age-related macular degeneration

Loss of central vision with preserved peripheral (navigational) vision; dry (drusen, geographic atrophy) and wet (neovascular) forms. Patients see a central dark patch and straight lines appear wavy on the Amsler grid.

Macular oedema and macular hole

Fluid in the macula (diabetic, post-surgical, after vein occlusion) blurs and distorts central vision. A full-thickness macular hole from vitreous traction causes a central scotoma and is repaired by vitrectomy with gas tamponade.

Macular sparing

In occipital infarcts from posterior cerebral artery occlusion, central vision is often preserved because the occipital pole (macular cortex) has collateral supply from the middle cerebral artery.

Test yourself

Which feature best distinguishes wet from dry age-related macular degeneration?

Presence of drusen
Loss of peripheral vision
Raised intraocular pressure
Choroidal neovascularisation through Bruch membrane

Answer: Choroidal neovascularisation through Bruch membrane

Wet (neovascular) AMD features choroidal new vessels breaching Bruch membrane, leaking fluid and blood and causing rapid distortion and central loss; it responds to anti-VEGF injections. Drusen and geographic atrophy characterise dry AMD; peripheral vision is preserved in both.