Retina Regional Differences

what are the two divisions of the retina?

central and peripheral

the central retina is dominated by rods or cons

cones

which part of the retina is relatively small, high resolution visual acuity, detail and color, has smaller retinal ganglion cell receptive field

central retina

how are cones arranged in the central retina

densely packed and squished

which part of the retina is dominated by rods

peripheral retina

makes up majority of the retina, has larger retinal ganglion cell receptive fields, detects gross motion and form

peripheral retina

how are cones arranged in the peripheral retina

widely spaced out and flatter

what is the retinal convergence at the fovea

low, 1:1:1

what is the retinal convergence at the periphery?

high, many: fewer: few

acuity is excellent where due to small receptive fields?

fovea

where is acuity poor due to large receptive fields?

peripherary

what structures are found at the central retina?

optic nerve, macula

what structures are found in the peripheral retina

equator, ora serrata

what is the diameter of the foveola?

0.3 mm

diameter of the fovea

1.5 mm

diameter of the parafoveal area

2.5mm

perifoveal diameter

5.5 mm

where is the macula lutea found

central retina

what is thicker in the macula lutea to support the high density of photoreceptors?

RPE and choroid

darkened area of central retina

macula lutea

the macula lutea contains a high concentration of what?

xanthophyll pigments

what does xanophyll pigments do

absorb short wavelengths and protective against UV radiation

What are two xanothphyll pigments

lutein, zeaxanthin

where do we get lutein and zeaxanthin

diet- dark leafy greens

the foveola is mostly what kind of cones

M-cone and L-cone

in the foveola there are very few ______ which are makes it insensitive to blues

S-cone

How many layers out of 10, does the foveola have?

6

What are the 6 layers present at the foveola 

Internal Limiting Membrane, Outer Plexiform, Outer Nuclear, External limiting Membrane, Photoreceptor Layer, RPE 

where in the central retina is the largest concentration of bipolar and ganglion cels

parafoveal area

inherited rod-cone degenerative disease, characterized by progressive blindness and progressive loss of peripheral vision

Retinitis Pigmentosa

Bone spicule pigment, waxy optic nerve pallor and attenuated vessels makes up the triad for which ocular disease?

Retinitis Pigmentosa

where is bone spicule pigment seen the most dense due to highest rod population

in the mid-periphery

underdevelopment of foveal pit

foveal hypoplasia

foveal hypoplasia is usually associated with other conditions that affect what?

development of the eye 

when you shine a light at the macula, the fovea will reflect a pinpoint light back, due to the parabolic shape of the fovea

foveal light reflex

what age patients are you likely to see foveal light reflex in?

young retinas/patients