Normal fundus
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Transcript of Normal fundus
Dr samarth mishra
Briggs coined papilla for optic disc Buzz,Sommering,Reil described macula Helmoltz invented eye mirror Ruete introduced indirect
ophthalmoscopy
Fundus is the portion of the inner eye that can be seen during an eye examination while looking through the pupil.
FUNDUS OCCULI
OPTIC DISC/PAPILLA MACULA LUTEA PERIPHERAL RETINA
Insensitive area in retina where ganglion cell axons exit eye to form optic nerve
Diameter-1.5mm Shape-round/vertically oval Colour-pale red/yellowsh red tint due to
lamina cribrosamedullated nerve fibres and
capillary plexus
Fibres continuous with sclera & choroid bridge the sclerochoroidal aperture forming a sieve like structure
LC is partly collagenous & partly neuroglial and derived from
Sclera (major part),pia mater &perivascular sheaths of central retinal
artery
Funnel shaped depression from which retinal vessels appear to emerge
15% cases do not show cup Nasal border steeper than temporal border Cup disc ratio- is<0.4 Depth of cup depends on –size, shape, obliquity ,vascularity of optic disc degree of development & regressionof hyaloid artery and glial tissue.
Diameter-5.5mm Situation-2DD temporal to OD Colour-yellow Function-photopic vision & colour vision Consists of- fovea centralis (1.5mm) foveola (0.35mm) parafovea(0.5mm),
perifovea(1.5mm),
Fully developed after 4yrs Diam - 1.5mm,0.25mm thick Situation - 4mm temp to OD 5 degree of visual field Foveola - no rods ,highest visual acquity Umbo - tiny depression in centre of
foveola Foveal avascular zone(0.4-0.6mm)
densely packed red & green cones central fovea has no rods
FOVEA 3MM AWAY FROM FOVEA
10MM AWAY FROM FOVEA
1,00,000- 3,24,000 cones/mm2Avg- 1,99,000 cones/mm2
6000 cones/mm2 4000 cones/mm2
Central retina:direct one-to-one relationship
In extra macular region
At least 1/3rd of all the nerve fibres which enter the ON originates in macular region.
Single cone cell Single bipolar cell
Single ganglion cell
20-100 cones 3-15 bipolar cells
Single ganglion cell
Nasal fibres-superior and inferior fibres
Macular fibres-papillomacular bundle
Temporal fibres-arcuate fibres
Nerves are nonmedullated
Near periphery – 1.5mm around ML
Mid periphery – 3mm around near periphery
far periphery – extend from OD 9mm on temporal side & 16mm on nasal side
Ora serrata - region where retina ends - 2.1mm wide temporally & 0.7mm
nasally
colour - orange to vermilion. Factors - amount of pigment in the
choroid, - hexagonal epithelium of retina & - Choroidal vasculature
At birth Choroid
unpigmented-most brilliant.
In old age Choroid fully pigmented
Greyish brown tint
Walls of choroidal BVs lost trasparency
finely granular or stippled texture. due to variation or unequal
pigmentation of hexagonal cells of pigmented epithelium of retina.
Watersilk reflex: Mainly patchy type. May be round, oval or irregular in
shape. They are highly mobile & elusive.
Tapeto-retinal reflex: seen near macular area
specular ill-defined patch of light against which a striking picture of the circumfoveal vessels can be seen
Gunn’s Dot: minute + highly glistening + colourless specs usually in the posterior part of the fundus
seen best in the course of the retinal nerve fibres above & below the disc
Weiss’s Reflex: annular reflex concentric with the border of the disc & is mobile
formed by the elevation of the internal limiting membrane where the nerve fibre layer is thickened
present at the nasal border of the disc
Many a times tunics of eye at the margin of OD don’t make contact with ON.
narrow zone of border tissue produces a narrow pale border to the disc, known as SR
mostly seen at the temporal
border of disc
Retinal vessels are end arteries.
anastomosis b/w the retinal vessels & cilliary system of vessels exist near the LC.
Retinal vessels form 4 groups to supply 4 quadrants of fundus
Only vessels in body not controlled by ANS
Blood flow 35-45ul/min 4% of total blood to eye Wall to lumen ratio-artery-1:5,vein-1:10 AV ratio-2:3 Mean retinal circulation-4-5sec 20% shows cilioretinal artery and vein
More on temporal than nasal Arteries never cross arteries and veins never
cross veins When 2 vessels cross they share a common
adventitia
Direct ophthalmoscopy Indirect ophthalmoscopy Biomicroscopic methods- negative lens positive lensHruby lens, El biyardi lens,
+78Goldmann3 mirror +90D,Mainster
lens panfunduscopic
lens
Done on a printed form with 12clock hours area
3 circles- inner corressponds to equator - outer to ora serrata, - outermost to anterior border of
pars plana ciliaris
Mydriasis Media OD-Size,shape,colour,margin,cup disc
ratio Macula-foveal reflex Peripheral retina Blood vessels
FUNDUS of eye is the only part of human body where microcirculation can be observed directly
THANK YOU