macular examination, jay chhablani

7/27/2019 Macular Examination, Jay Chhablani

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Evaluation of Macula

Dr Jay Kumar Chhablani

Smt. Kanuri Santhamma Retina &Vitreous Centre


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Anatomy of macula


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Evaluation of macula

History Examination Investigations


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History

Distortion of images Blurring of images Unable to identify faces Difficulty in color vision


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Examination

Binocular indirect ophthalmoscpy Slit-lamp biomicroscopy


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Slit lamp Biomicroscopy

Slit lamp-

Adjustable intense illumination

Slit beam adjustable width / length 3600 rotation, variable angle

Provides optical section Provides high magnification and stereopsis Surface contours of chorioretinal lesions better

appreciated


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Slit lamp biomicroscopy

Principle-

Use of an accessory lens to image the fundus in aposition, where it can be reimaged by slit lamp


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Accessories-

Contact lenses:-Neutralizes corneal power

Noncontact lenses: use refractive power of cornea and high convex /

concave lens to image the fundus

Slit lamp biomicroscopy


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Advantages

NONCONTACT METHOD

Quicker Examine post op. and

infected patients

No coupling agent No topical anaesthesia

CONTACT METHOD

Better stability Better quality of

image

Some control ofocular movements


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Lenses used

NON CONTACTMETHOD

Hruby lensAspheric lenses(+60, +78, +90D)

CONTACT METHODGoldman three mirror lensGoldman posterior lensMainster lensPanfundoscopicQuadrisphericVolk Super Quad


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Non Contact Methods

Hruby lens-

Plano concave (-58.6 D) Mounted on slit lamp View: 300 vertical / 600 lateral Image : Erect / virtual / in pupillary plane

Minification of pupil To view only post. pole


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Non Contact Methods

Indirect fundus biomicroscopy-

High convex lenses (+60D, +78D, +90D) Image : Real, Inverted, High quality Magnify the pupil - wider fieldFundus scanning : Upto pre equatorial region with certain adjustments


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Volk TransEquator

132 Dynamic Fieldof View

0.7x Magnification 1.44 Laser Spot

Magnification Factor

13


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Volk SuperQuad 160

160 Field of View 0.5x Magnification 2.0x Laser Spot


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Mainster Lens

35 - 48 Dynamic Fieldof View

0.95 x Magnification 1.05 Laser Spot


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Indirect fundus biomicroscopy

Technique-

Narrow slit width / low intensity Lowest magnification Align illumination / visualization angle straight ahead Focus the cornea with beam passing through dilated

pupil

Hold the lens in front of pupil Pull the slit lamp back to get fundus image


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Increasing field of Exam-

Shifting patients gaze Changing beam width / magnification Moving Slit Lamp

Vertically / Horizontally Vertical tilt by 150


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LENS

FEATURE 60D 78D 90D

Magnification 1.18D 0.95D 0.75

Field of view 76 degrees 84 degrees 94 degrees

Focal length 19mm 15mm 12mmClear lens aperture 30mm 29mm 19mm



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Contact Lens Methods

Needs coupling solution Topical anaesthesia cannot be used in immediate post op. period / infectionAdvantages:

Better stability Better quality of image (less interfaces) No need to retract the lids Can control ocular movements


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3 mirror lens (Goldmann)-

Clear central portion planoconcave (-64D)Views central 300 of an emmetropic eye

Radially arranged 3 mirrorssmall (590) - for Gonioscopy, region anterior to oramiddle (670)-pre-equatorial partlarge (730) -post. pole to equator


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3 mirror lens (Contd.)-

ImageCentral lens : Erect, virtualPeripheral mirrors : A-P inverted

: Not laterally reversed


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Contact lens methods


Technique Position patients head on slit lamp Hold the lens in first 3 fingers Ring finger to retract lower lid Patient to look up Place the lens on cornea Patient to look straight ahead


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Slit lamp Slit beam along the radial axis of mirror

Evaluate fundus by Rotation of mirrors Readjusting the slit beam Redirecting the patients gaze


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Panfundoscope lens (Rodenstock)-

Meniscus lens coupled with spherical lens (+81 D)

Image : Real, inverted Within the lens Minification (0.7X)

Wide angle view (upto equator) More useful for Laser photocoagulation


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Mainster lens-

Meniscus lens with double aspheric lens Image

Inverted, real High lateral and axial magnification Excellent resolution

Image plane is very anterior - Difficult focusing Used for examination / Laser treatment


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Mainster lens: Modifications-

View Magnification

(degrees) Standard 90 0.96x Ultrafield 140 0.53x Widefield 125 0.68x High mag. 75 1.25x


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Care of Lenses

Sterilization : ETO gas (520 C) Cleaning:

Rinse in cold / tepid water Clean with dishwashing liquid Rinse and blot dry with lint free cloth

Disinfection: 2% Glutaraldehyde - (20 min.) Rinse in cool water dry 1:10 sol. of Na. hypochlorite (10 min) Rinse Dry

Never boil or Autoclave


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Investigations


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Visual acuity measurement Color visionContrast sensitivity

Amsler charts Visual discrimination tests (Two point

discrimination) Entoptic imagery tests


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Fundus fluorescein angiogram ICG angiogramOCT

Elecrophysiology


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Pinhole visual acuity Clinical interferometersGuyton-Minkowski Potential Acuity Meter(PAM)

Visual acuity measurement


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Blue field entoptoscopy

penlight ortransilluminator

To observe the flowof white blood cells in

the parafoveal

capillaries.

Blue light is absorbedby the red blood cells

but not the white

blood cells.


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Two-point discrimination

Two light sources of equal intensity About 25 inches (or 62 cm)No information is learned about macularpotential.

Fully mature cataracts or otherwise denseocular media.

Gross color perception


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Potential acuity

PAM Reducedsnellen chart

Laser inferometry


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Contrast sensitivity

Terry Acuity Pelli-Robson


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Amsler: Set-up

Pt holds grid 28cm-30cm Grid should be brightly illuminatedPt should be wearing best-corrected Rx fornear

10 degree of the visual field10 cm square

AMLSER GRID: Charts


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1: Standard grid (mostcommon)

black lines on whitebackground or white lines onblack background

central fixation spot

AMLSER GRID: Charts


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AMLSER GRID: Charts

2: chart 1 with diagonal lines" Use on pt w/

central scotoma fixation problems

" Help maintain fixation

pt fixate at intersection ofdiagonals lines

AMLSER GRID Ch t


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AMLSER GRID: Charts

3: Red grid on black background acts like a Red desaturation test

toxic amblyopic pts better for relative scotomas


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AMLSER GRID: Charts

4: Random dots Pt with paracentral

relative scotomas

can delineate defectsbetter due to no linedistortion


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AMLSER GRID: Charts

5: Parallel horizontallines

Sensitive tometamorphopsi

a b/c lines

adjusted to

defects

orientation


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AMLSER GRID: Charts

6: chart 5 w/additional horizontal

lines 1 degree

above & belowfixation

" Helpful for evaluation

complaints ofmetamorphopsia @

the reading level


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AMLSER GRID: Charts

7: breaks horizontalcentral area

3cm X 4cm square more sensitive to

subtle defects in the

fovea


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Color vision

Ishihara pseudo isochromatic charts FM 100 hue test D 15 test


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Farnsworth D-15 Color Vision Test


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Fransworth Munsell 100 hue test


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Photo Sttress Test

BCVA checked Pen torch / indirect about 3 cm away for abou

10 seconds

Photostress recovery time - to read any threeletters of the pre-test acuity line (15-30

seconds)


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Optical Coherence Tomogram(OCT)


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Central Serous Retinopathy


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Pigment Epithelial Detachment

M l h l


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Macular hole

T i


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Traction


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macular examination, jay chhablani

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