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8/6/2019 Hruby Lens Nik
1/18
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8/6/2019 Hruby Lens Nik
2/18
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8/6/2019 Hruby Lens Nik
3/18
Nullify it.
Utilise power of cornea as a telescope.
This is to view posterior pole and posterior
vitreous.
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8/6/2019 Hruby Lens Nik
4/18
Powerful plano-convex lens
Power = -58.6D
Virtual, erect and dimnished image of
illuminated retina.
Restricted field of 5-8 degrees or just larger
than one disc diameter.
As an attachment from either above or below
that can be rotated into the line of sight.
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8/6/2019 Hruby Lens Nik
5/18
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Patient co-operation is extremely important .
Focus the oculars to accommodate any practitioner
refractiveerror, set the pupillary distance, remove all filters and
set themagnification to the lowest setting, usually 6-10x.
The illumination of the slit-lamp should be adjusted for an
intermediate slit height and a 2 mm width, and then placed inthe
straight ahead position.
The height of the patient is adjusted with the chin rest so
thatthe fixation device is in the centre of the patient's field in
frontof the contra-lateral eye.
After the slit-lamp is moved into position so that the slit
isimaged in the patient's pupil, the Hruby lens is introduced
in
front of the patient's eye as close as possible
withoutcontacting the cornea or lashes.
The plano side of the lens should be toward the examiner.
The patients eye is then moved in all directions with the
eyefixed on the object, depending on areas to be examined.
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8/6/2019 Hruby Lens Nik
7/18
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8/6/2019 Hruby Lens Nik
8/18
Stereoscopic viewing of the opticcup and macula.
Useful for viewing the vitreous.
When used with redfreeillumination, the hruby lens
candemonstrate the optically emptyspace between the
posteriorvitreous face and the retina in thecase of a posterior
vitreousdetachment
The main disadvantage of thistechnique is the field of view
lessthan two disc diameters for anemmetropic patient).
More dilation is required than inother binocular techniques.
The quality of the image is easilydegraded by media
opacities.
As the magnification is so high,small movements of
thepractitioner, lens, or patient havean immediately
noticeablenegative effect on image quality.
Because the lens does not come incontact with the cornea, like
a
contact Hruby lens, reflections aresomewhat of a problem.
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8/6/2019 Hruby Lens Nik
9/18
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8/6/2019 Hruby Lens Nik
10/18
High powered, biconvex, condensing lens.
Projects an INVERTED, REVERSED, REAL image in
front of the lens.
Higher the power-lower the magnification but
greater the field of view!!!
Either clear or yellow filter.
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8/6/2019 Hruby Lens Nik
11/18
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8/6/2019 Hruby Lens Nik
12/18
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8/6/2019 Hruby Lens Nik
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Emmetropic Eye Is Considered To Be 60
Diopters
MAGNIFICATION = POWER OF THE EYE /
POWER OF THE CONDENSING LENS MAG. =
60D / 90D
MAG. = .666 X MAGNIFICATION OF SLIT LAMPMAG. = .666 Times
10X
MAG. = 6.66 X (ETC.)
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8/6/2019 Hruby Lens Nik
14/18
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8/6/2019 Hruby Lens Nik
15/18
Image of the Left OpticDisc and Vessels as SeenWith a 90D LENS
and Slit
Lamp. The Image Seen isInverted. TheMagnification isincreased,
and the Fieldof View is Large.
Direct view of the leftoptic disc as seen with
a non-contact HRUBYLENS and slit lamp. Itshows decreased
andreduced field of view.
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8/6/2019 Hruby Lens Nik
16/18
1.)Papilloedema
2.) Drusens of the nerve head
3.) Neovascularization of the nerve head (diabetes)
4.) Estimating the cup to disc ratio (glaucoma
diagnosis)5.) Optic atrophy (color and lack of vessels)
6.) Cystoidal macular degeneration
7.) Macular edema (central serous retinopathy)
8.) Retinal detachments
9.) Evaluating the nerve fiber layer of the retina (red-
free, cobalt)10.) Posterior vitreous detachment
11.) Macular holes, cysts, hemorrhages, scars,
pseudoholes, etc.
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8/6/2019 Hruby Lens Nik
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8/6/2019 Hruby Lens Nik
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