Oftalmo 1st test Flashcards
Dimensions of the eye?
23.5mm x 23mm (vertical), 22-24mm (AP)
Size matters for refraction
weight of the eye
7.5g
2 poles of the eye
○ An equator - maximum circle perpendicular to AP axis
○ 2 meridianos: § Anterior pole - □ center of the cornea, □ transparent □ Most external layer □ avascular
§ Posterior pole □ Retina and optic nerve □ Most internal part □ To see these parts have to dilate the pupil
What are the 3 cameras of eye?
to have good vision all cameras need to be transparent
anterior
posterior
vitrea
anterior camera
between iris (color) and cornea
○ the aperture of iris = pupila, ○ Contains aqueous humor ○ Measures 3mm deep ○ Volume of 250 µL. ○
posterior camera
medial to iris and ciliary body, anterior to crystalline lens and vitreal cavity,
○ 60uL volume
○ 4.5mm deep
○
○ (No hay medio acuoso casi, solo lente).
vitrea
constitutes > 2/3 of volume of eye
○ Contains vitreal gel
○ 5-6ml
○ Gives form to eye
What happens When there is an increase in production of aqueous humor or when there is no proper drainage?
–> increase in intraocular pressure and affection of II
Define catarats?
- when in this (post camera ) area, crystalline lens opacifies
What do zonulas do?
- Permit accomadation of lense
- With age this decreases –> presbicia
The zonule of Zinn (Zinn’s membrane, ciliary zonule) (after Johann Gottfried Zinn) is a ring of fibrous strands connecting the ciliary body with the crystalline lens of the eye. These fibers are sometimes collectively referred to as the suspensory ligaments of the lens.
Only thing that detaches?
Retina
How to see II?
neuroimages
embryological development of the eye
- Formed in day 25 from optic fossettes
- Derived from prosencefalus
- Differentiates in days 26-28 in optic vesicles
sturctures of the eye from the neuroectoderm?
retina, II, sphincter muscles, dilator of iris, posterior iridian epithelium, epithelial ciliar body
sturctures of the eye from the superficial ectoderm?
crystalline, corneal epithelium, eyelid epidermis, lagrimal gland and tarsal/eyelid conjuntiva (covers eyelids, bulbar conjuntiva which covers sclera)
sturctures of the eye from the neural crest or ectomesenquim?
keratocytes, scleral fibroblasts, trabeculum endothelium, coiroid stroma, iridian, ciliar SM, meninges, orbital fibroadipous tissue, carillage, and orbitary bones
sturctures of the eye from the mesoderm or mesenquime?
extraocular muscles and vascular endothelium
3 layers of the eye
external: cornea sclera
middle: uvea
internal: retina
cx of cornea
§ Most external
§ Normally transparent
§ avascular
§ 6 layers (stratified)
§ Trigeminal innervation § : ○ 90% del espesor corneal: colágeno y queratocitos, .
cx of sclera
§ Continues with meninges and DM
§ CT , dense, similar to cartilage
§ Avascular
§ Insertion of extraocular muscles § Lamina cribosa at posterior part - exit of optic nerve fibers
uvea cx
§ Anterior: iris and ciliar body
§ Posterior: coroides
Only part of eye transplanted? Only part that hurts?
cornea
6 layers of the cornea
stratirifed
○ se descubrió una sexta capa que se encuentra entre descemet y el endotelio, la capa dua.
Epithelium.
Bowman’s.
Stroma. ○ Lesion here or deeper –> leocoma = scar
Dua’s layer.
Descemet’s.
Endothelium.-: maintaines corneal dehydration (avoid blurry vision).
function of sclera
structural support of eye