Anatomy Flashcards
Development of eye starts from _________ day of gestation
22 nd day of gestation
___________ gene plays an important role in development of eye
PAX6 gene
Defect in this gene leads to
MICROPHTHALMIA
ANOPHTHALMIA
How to diagnose MICROPHTHALMIA
Axial length of eye ball is less than 21 mm in adults
Axial length of eye ball is less than 19 mm in children of age less than 1 year
Lens is derived from ____________
Surface ectoderm
lens is only internal structure derived from surface ectoderm whereas most of internal structures are derived from neuroectoderm
what is the Junction B/W Selera and corner is called?
Limbus
what are the Layers that are present above sclera?
sclera-> Episclera -> Tenons capsule
True/false: conjuctiva is Thin mucous membrane that cover complete anterior surface of Eye
false
##
conjunctiva does not cover cornea
what are the parts of conjunctiva ?
Bulbar conjunctiva
fornices (superior, inferior, medial, Lateral)
palpebral conjunctiva (marginal, sulcus subtarsalis, tarsal,orbital)
which part of Eye divides eye into Anterior segment and Posterior segment?
Lens
what is the structure present B/w Anterior & Posterior chamber?
Iris
what are the parts of cillary body?
rough Part-pars plicata
smooth part-pars plana
## foot note
Pars plicata is rough due to the presence of ciliary process from which Aqueous humor
circulation of Aqueous Humor
conventional Pathway
1.ciliary process of POSS plicata of Cilliary body
2. Posterior chamber.
3. Pupil
4. Turbecular mesh work of Angle of Anterior chamber
5. Schlemms canal of Ange of Anterior chamber
6. episcleral venous system
unconventional Pathway (uveo scleral outflow)
- root of Iris (sweep though and around tissues, including supra cillary space)
- ciliary muscle
- Supro choroidal space
4.choroidal vessels - emissary canals
- sclera
- Lymphatic vessels
what are the major refracting surfaces of Eye?
cornea -1.37 (Refractive index)
Lens-1.4 to 1.41 at Centre & 1.39 overal (refractive index)
Power of cornea -43-45 D
Power of Lens -16-17 D
MCQ
what of Image is formed on Retina
A) errect image
B) Inverted Image
Inverted Image
## foot o note
at nodal point (behind Lens ) the Image gets Inverted and falls on the retina & Then Image is made striaght by our bolan
what is the nodal point of eye?
It is the optical Center of the eye. It is also first focal point that is situated behind the Lens
what is the shape and capacity of the eyeball?
Shape- oblate Spheriod
Capacity-6 to 7 ml
what is scotoma?
Any non seeing area surrounded by seeing area is called scotoma
what is ora Serrata?
The peripheral most part of retina hear pars plana of ciliary body is labelled as oraserrata
what are the avascular structures that get nurishment from Aqueous humor?
Cornea & Lens
##footnote
foveal avascular zone : fovea centralis of Retina is also Avascular. But it won’t get nourishment from aqueous humour
what is Lamina cribrosa?
Lamina cribrosa is sieve like part of sclera that present at optic disc and encircles optic circle
what is the shape & capacity of orbit?
shape of orbit is Pyramidal (or) quadrilateral
capacity of orbit is 30cc
what is the length of optic nerve
5 cm [ 3.5 cm to 5:5cm ]
what is the axial length of eyeball and it is measured?
24 mm
it is measured using ultra sound scan
A scan is used to measure Axial Length of eyeball
B scan is used to see the posterior segment of eye
what is the depth of the anterior chamber?
Area in b/w the IRIS & CORNEA
& it measure about 2.4 to 2.5 mm
what is Anisometropia?
Anisometropia is condition in which difference B/W refractive Power of Both eyes is greater than 2.5 D
what are the parts of Retina?.
Peripheral
mid-Peripheral
Central retina [ optic disc, macula (fovea centralls, foveola, umbo) ]
what’s part of the retina from which the optic nerve exits ?
optic disc
optic disc will presnt on Nasal side retina
what part of Retina is responsible for Central vision?
Macula (it is also known as macula Lutea as it is in yellow colour)
##footnote
macula will present on the temporal side retina
what is the most sensitive part of the retina?
foVea Centralis
foveola contains cones only
what is the small depression present in macular region of reting as called?
umbo
what is the thinnest part of retina?
fovea
How much distance is present B/W optic disc and foveola?
2 disc diameters (or) 3mm
what are the charts used in testing Central vison & Peripheral vision ?
Central vision is checked though visual acuity charting
peripheral vision is tested though perimetry (or) peripheral visualfield charts
what is the instrument used for examining retina and mention its types?
ophthalmoscope:
A) Direct ophthalmoscope
B) Indirect ophthalmoscope
ophthalmoscope is also know as fundoscope
what is the instrument used for doing refraction of the eye?
retinoscope
