Fundus (eye)

Fundus
Fundus of human eye
Anatomical terminology [edit on Wikidata]

Fundus photographs of the right eye (left image) and left eye (right image), as seen from the front (so that left in each image is to the person's right and the person's nose would be between the two images).

Each fundus has no sign of disease or pathology. The gaze is into the camera, so in each picture the macula is in the center of the image, and the optic disk is located towards the nose. Both optic disks have some pigmentation at the perimeter of the lateral side, which is considered non-pathological.

The left image (right eye) shows lighter areas close to larger vessels, which has been regarded as a normal finding in younger people.

A fundus photo, showing the optic disc as a bright area on the right where blood vessels converge. The spot to the left of the centre is the macula. The grey, more diffuse spot in the centre is a shadow artifact.

Structure

The fundus of the eye is the interior surface of the eye opposite the lens and includes the retina, optic disc, macula, fovea, and posterior pole.^[1] The fundus can be examined by ophthalmoscopy^[1] and/or fundus photography. The term fundus may also be inclusive of Bruch's membrane and the choroid.

Variation

The color of the fundus varies both between and within species. In one study^[2] of primates the retina is blue, green, yellow, orange, and red; only the human fundus (from a lightly pigmented blond person) is red. The major differences noted among the "higher" primate species were size and regularity of the border of macular area, size and shape of the optic disc, apparent 'texturing' of retina, and pigmentation of retina.

Clinical significance

Medical signs that can be detected from observation of eye fundus (generally by funduscopy) include hemorrhages, exudates, cotton wool spots, blood vessel abnormalities (tortuosity, pulsation and new vessels) and pigmentation.^[3] Arteriolar constriction, seen as "silver wiring", and vascular tortuosities are seen in hypertensive retinopathy.

The eye's fundus is the only part of the human body where the microcirculation can be observed directly.^[4] The diameter of the blood vessels around the optic disc are about 150 μm, and an ophthalmoscope allows observation of blood vessels with diameters as small as 10 μm.^[4]

References

See also

Wikimedia Commons has media related to Ocular fundus.

• Dilated fundus examination
• Fundus camera
• Leukocoria
• Red-eye effect
• Tapetum lucidum

Anatomy of the globe of the eye Fibrous tunic (outer) Sclera Episcleral layer Schlemm's canal Trabecular meshwork Cornea Limbus layers Epithelium Bowman's Stroma Descemet's Endothelium Uvea/vascular tunic (middle) Choroid Capillary lamina of choroid Bruch's membrane Sattler's layer Ciliary body Ciliary processes Ciliary muscle Iris Stroma Pupil Iris dilator muscle Iris sphincter muscle Retina (inner) Layers Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium Cells Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia Other Macula Foveola Fovea centralis Parafovea Perifovea Optic disc Optic cup Anterior segment Anterior chamber Aqueous humour Posterior chamber Lens Capsule of lens Zonule of Zinn Posterior segment Vitreous humour Other Asthenopia Keratocytes Ocular immune system Tapetum lucidum