1. INSTITUTO DE LA VISION
07 marzo 2011
Dr. Fily Martinez D.

2. RETINA:

3. Retina: develops as part of the brain
1. (outer layer) Fibrous: dense connective tissue
Sclera – white of the eye
Remember
the 3 layers of Cornea
the external 2. (middle layer) Vascular: uvea
eye? Choroid – posterior, pigmented
Ciliary body
Iris
3. (inner layer) Sensory
Retina and optic nerve
Retina is 2 layers
 Outer thin pigmented layer:
 Melanocytes (prevent light scattering)
 Inner thicker neural layer
 Plays a direct role in vision
 Three type of neurons: 1. Photoreceptors
2. Bipolor cells
3. Ganglion cells 3

4. Light passes through pupil in iris, through vitreous humor,
through axons, ganglion cells and bipolar cells, to
photoreceptors next to pigmented layer
4

5. Photoreceptor neurons signal bipolar cells, which signal
ganglion cells to generate (or not) action potentials: axons run
on internal surface to optic nerve which runs to brain
*Know that axons from the retina form the optic nerve, CN II
5

6. Photoreceptors: 2 types
 Rod cells
 More sensitive to light - vision permitted in dim
light but only gray and fuzzy
 Only black and white and not sharp
 Cone cells
 High acuity in bright light
 Color vision
 3 sub-types: blue, red and green light cones
*Know that rods are for B & W and cones are for color
6

7. If you want more
detail, it’s
fascinating…
7

8. Retina through
ophthalmoscope
 Macula: at
posterior pole
 Fovea: maximal
visual acuity
(most
concentrated
cones)
 Optic disc: optic
nerve exits
 Vessels
8

9. Green is area seen by both eyes, and is
the area of stereoscopic vision
Visual pathways
At optic chiasm, medial fibers from each eye
(which view lateral fields of vision) cross to
opposite side. Optic tracts (of crossed and
uncrossed, sensing opposite side of visual field of
both eyes) synapse with neurons in lateral
geniculate of thalamus. These axons form the optic
radiation and terminate in the primary visual cortex
in the occipital lobe. Left half of visual field
perceived by right cerebral cortex, and vice versa.
9

10. TIPOS CELULARES:
 CEL. FOTORRECEPTORAS: CONOS Y BASTONES.
 CEL. HORIZONTALES.
 CEL. BIPOLARES.
 CEL. AMACRINAS.
 CEL. INTERPLEXIFORMES.
 CEL. GANGLIONARES.

12. CAPAS DE LA RETINA:
1. EPR: CELULAS PIGMENTADAS.
2. CAPA DE FOTORRECEPTORES: CONOS Y BASTONES.
3. MLE: UNION INTERCEL. ENTRE CEL. FR Y CEL. DE MÜLLER.
4. CAPA NUC. EXT: FORMADA POR LOS NUCLEOS CELULARES DE
LAS CEL. FOTORRECEPTORAS.
5. CAPA PLEXIFORME EXT: CONEXIÓN SINAPTICA DE CEL. FR, BIP
Y HORIZ.
6. CAPA NUC. INTER: FORMADA POR NUC. DE LAS CEL.
BIP, HORIZ. Y AMACRINAS.
7. CAPA PLEX. INTER: CONEXIÓN SINAPTICA ENTRE CEL.
BIP, AMACRINAS Y GANGLIONARES.
8. CAPA DE CEL. GANGLIONARES.
9. CAPA DE FIBRAS NERVIOSAS.
10. MLI: LAMINA BASAL QUE SEPARA LAS CEL. DE MÜLLER.

14. RETINA: EPR
•ES UNA MONOCAPA DE CELULAS QUE
CONTIENEN MELANOSOMAS.
•TEJIDO VITAL PARA EL
MANTENIMIENTO DE LA FUNCION
FOTORRECEPTORA.
•UNO DE LOS TEJIDOS CON MAYOR
ACTIVIDAD METABOLICA.

16. FUNCIONES DEL EPR:
•REGULACION DE LA TEMPERATURA
•MANTENIMIENTO DE LA BARRERA
HEMATORRETINIANA EXTERNA
•ADHESION RETINIANA
•ABSORCION DE LA LUZ

17. FUNCIONES DEL EPR:
• FAGOCITOSIS DE LOS SEGMENTOS
DESPRENDIDOS DE LOS
FOTORRECEPTORES
• APORTE DE O2 Y NUTRIENTES A
FOTORRECEPTORES
• TRANSP. ACTIVO DE MAT. DENTRO Y
FUERA

19. RETINA: ELEMENTOS VASCULARES
 CIRCULACION COROIDEA RETINA EXT.
 ART. RETINIANA CENTRAL RETINA INT.
 CIRCULAC. MACULAR ART. CILIORETINAL
 VASOS SANGUINEOS RETINIANOS MANTIEN LA
BARRERA HEMATORRETINIANA INTERNA

20. Thank you. Retina
Service.