RAJVIN SAMUEL PONRAJ

APPERANCE : Uniform red

Punctate stippling-periphery Varies-color of individualNormal choroidal vessels

- Invisible PARTS : DISC

VESSELS MACULA

PERIPHERY

ORA SERRATA – Junction between peripheral retina and pars plana

CONTENTS - DENTATE PROCESSES ORAL BAYS

NORMAL VARIANTS : Meridoneal fold enclosed bay microcystic degeneration granulation tissue

LAMINA CRIBROSA

NEURORETINAL RIM

DISC: LOCATION –nasal to geometric axis

DIAMETER – 1.5mm [1 disc diameter] COLOR – Pale pink SHAPE – Circular EDGES – Regular TERMINATION OF ALL LAYERS EXCEPT NFL

CUP: C/D ratio – 0.3 to 0.5

RETINAL SYSTEM : CENTRAL RETINAL ARTERY AND CENTRAL RETINAL VEIN

4 major branches Arterioles

Venules Capillaries

CILIARY SYSTEM : POST.CILIARY ARTERIES Choriocapillaries

Specialised region of retina Diameter – 5.5 mm Location – 2 DD - temporal margin of discColor – Yellow; deep pigmented 4 zones : Foveola -0.35 mm

Fovea -1.50 m Parafovea

Perifovea Retinal vessels Cilioretinal artery

Fovea - Thin bottom thick basement margin - prone for macular holes -Henle’s layer-oblique conesFoveola - Thin pit , Densely cones Bowing vitreally- fovea externaUmbo - Tiny depression - Foveal light

reflex bouquet of cones - narrowed gateau nucleaire

Posterior pole – loss of foveal light reflex drusen

Retinal vessels – narrowing, increased light reflex

Equator - chorio , reticular pigmentary degeneration

Vitreous - liquefaction , floaters ,..

Why it is performed:

It can detect some signs & physiological effects of various circulatory, metabolic and neurological disorders.

Routinely used to assess and diagnose vitro-retinal diseases (such as Diabetic retinopathy, retinal tear and detachment, macular hole, retinal haemorrhage, retinal artery and vein occlusion, choroidal tumor, or macular edema), optic nerve defects, and hereditary diseases.

Fundus examination is used to:

Identify and locate vitro-retinal and optical nerve defects caused by eye diseases or trauma.

Examine the extent of the defects or abnormalities to plan a proper treatment.

Evaluate the success of treatment.

Combination of phenylephrine [2.5 %] & tropicamide [1 %] then eyes closed

Dilation attained = 45 min Normal reactivity = 4 - 8 hrs

Conditions which to avoid : iris supported lens shallow AC Head injury

- retinal arterioles - exudate retinal haemorrhage edema microaneurysm attached retina - vitreous opacity hole /break vitreous bleed

- Retinal venules - pigmentation detached retina detached

choroid outine of break - ora serrata

/drusen

hyperpigmentation

Vitreoretinal chart Optic Disc drawing

METHODS OF EXAMINATION

DIRECT OPHTHALMOSCOPY

INDIRECT OPHTHALMOSCOPY

INDIRECT SLIT LAMP BIOMICROSCOPY

DIRECT OPHTHALMOSCOPY

An erect upright virtual imageMagnification = 15 xField of view = 5 degreesOptimal working distance upto 2-3 cmsNo stereoscopic viewSeveral plus and minus dial up lenses Structures - optic nerve, blood vessels of posterior pole fovea Viewing aperture contains illumination openings 1. spots 4.fixation target 2.streak projection 5. calibration grid 3.Red free filter

Evaluating fundus :

Indirect ophthalmoscopy

An inverted reverse real imageMagnification = 2 to 4 XField of view = 40 to 50 degreesOptimal working distance = 40 to 50 cmsGood illumination & stereopsisEase of use with scleral indentorLenses from 14 to 30 D range

Positioning of patient

Head set adjustment

Eye piece adjustment

Light beam adjustment

Choosing ,positioning and technique to hold condensing lens.

12 ‘0’ Clock meridian towards patient’ feet

and transforming the image rotated 180 degrees .

Follow vessels and bifurcations in each quadrant then with scleral indentation terminal branches.

Ora serrata then fundal lesions with relations .

Field of view is proportional to power of lens but inverse of magnification

Hence wider field will have less magnification with higher powered lenses.

Higher power lenses used in small pupils, peripheral fundus view.

-Thimble scleral depressor

-Pencil type depressor-Cotton tipped applicator

To examine periphery between equator and ora serrata by creating a mound to view. Start superonasal superior ,superotemporal,Inferotemporal, inferior, inferonasal

An inverse real reversed image with hand held lenses

Field of view = 30 to 40 degrees Lens power = + 78 or + 90 D , other lenses= +

60 to 132 DMagnifying knob to 10 X or 16 X

Drawing the slit lamp biomicroscopic view: Done on an inverted fundus chart and paper is

turned as patients gaze direction changes in respective clock hour meridian.

Performing indirect slit lamp biomicroscopyEvaluating fundus :

A plano concave non –contact lens High minus power [-55 D]Virtual erect imageTo visualize - optic cupping , peri papillary changes - Nerve fibre layer thickness [red free

filter] - Macular lesion level [slit beam side

way movement] [watzke

Allen test] - Vitreous opacities, strands.

Concavo plano contact lens - virtual , erect imageCombines stereopsis, high illumination, high

magnification [ 10 x] , 20 degree field,..Flat central portion – posterior vitreous and pole

Angled mirror - 73 deg - area around posterior pole

67 deg - equatorial fundus 59 deg - peripheral retina

Eliminates total internal reflection by replacement with cornea – goldmann contact lens interface.

Provides wide field 130 degree and high power lens

A real inverted magnified image is formed

It is used in both posterior fundus examination and also Laser pan retinal photo Coagulation.

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