fundus lens

7/29/2019 Fundus Lens

1/15


2/15

1.) The plano side of the lens should be toward the examiner and the slitlamp and illumination system should be in click position.

2.) Adjust the slit width to 2 - 3mm and magnification 10 X then from

outside (with the patients eyes closed) move the slit lamp forward untilthe slit appears focused on the patient's lid.

3.) Have the patient open their eyes and give them your fixation

instructions.

4.) There should be a red retro-glow within the dilated pupil. Now movethe slit lamp forward slowly until retinal vessels are seen.

5.) Once you have located the structure you are wanting to evaluate; youcan increase the magnification to 16 X or higher. Look for venous

pulsation when viewing the disc.

6.) If you are wanting to view the macula foveal area I suggest youinsert the red-free filter for comfort reasons. This is not something you

will do on every patients, but rather when it's indicated. You'll notice that

with the red-free filter in place the macula foveal area appears yellowishplus you should see the foveal reflex. The red-free or the cobalt blue

filters will also make the nerve fiber layer of the retina more visible.

7.) The slit width is narrowed down to an optic section (the slit lamp and

illumination system remain in alignment, click position) it will help youevaluate elevations or holes. An optic section of the retina is not thesame as the cornea. It is nothing more than a finely focused, narrow slit

on the area of concern. You do not get the three dimensional viewthrough the retina as seen when viewing the cornea or crystalline lens.

You do get a stereoscopic appreciation for deflections or elevations and

transillumination on either side of the optic section in certain conditions.

Locate the optic nerve then give the patient instructions so you can

follow the superior and inferior vessels out as far as possible and then


3/15

back to the optic nerve head. Place the red-free filter in place and findthe macula-foveal areas.

FIELD OF VIEW IS SMALL & MAGNIFICATION IS LARGETHE VIEW SEEN IS A DIRECT IMAGE

Slit Lamp Aspheric Biomicroscopy Indirect Fundus Lenses

These lenses have an advantage over the non-contact Hruby allowing abetter view around cataracts. These lenses are double aspheric and come

in +90D, +78D, and +60D powers. There is no correct direction for

holding the lenses; either side can face the patient. With these indirectfundus lenses magnification increases as power of the lens decreases,

similar to that found with condensing lenses utilized for binocular indirectophthalmoscopy. The +60 D lens gives greater magnification and is

preferred by some for examination of the optic nerve and macula. The+90 D lens produces less magnification and larger field of view (30-40

degrees) [Barker, 1987]. However, the slit lamp biomicroscope permitsvariable magnification which neutralizes this magnification problem.Theoretically, the increased field of view would permit easier examination

of the peripheral fundus to the equator and ora serrata. Clinically, if thepupil is fully dilated, the magnification is set on low, and there is good

patient cooperation, this can be accomplished with any of the three

lenses. The +78 D lens obviously falls in between the +60 D and +90 Dlenses in terms of magnification and field view. It is slightly smaller in

overall size than the +60 D and noticeably larger than the +90 D lens.The +78 D lens is usually preferred by the novice who feels it is easier to

hold and manipulate. Recent report has given preference for the +78 D

over the others to study the nerve fiber layer [Litwak, 1990].

One potential disadvantage of the +60 D has to do with its longer focal

length and the extent that the slit lamp must be pulled away from the

patient in order to focus on the aerial image in front of the condensinglens. Some older model slit lamps may not have enough of a range to

bring this image into clear focus. Even the +90 D lens when used on


4/15

some patients can be challenging.

All three lenses are available either in clear or with a yellow tint. Theyellow tint filters the wave-lengths below 480 nm, enhancing patient

comfort and acceptance. The yellow tint causes a slight color shift in theappearance of the retina which could cause misinterpretation of optic

nerve pallor and makes detection of the macular edema more difficult

[Barker, 1987]. In lieu of an actual tint to the condensing lens itself,other products are also available to provide yellow illumination. One

version of this consists of utilizing a filter which attaches directly to theslit lamp; another is that of a removable yellow filter which may be

attached and detached from the condensing lens itself. The vitreous of

the eye can also be examined with these lenses. Remember, the vitreousis anatomically located in front of the retina, therefore, you have to pull

the slit lamp farther back towards you to view the vitreous body.

SIMPLE MAGNIFICATION

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 LAMP

MAG. = .666 Times 10X

MAG. = 6.66 X (ETC.)

The indirect biomicroscope lens is not intended to take the place of thebinocular indirect ophthalmoscopy, but allows you to view an area

stereoscopically and with higher magnification than with the binocularindirect ophthalmoscope.

Image Location Using a Funduscopic Lens

Microscope Aerial Image+ 78D Lens


5/15

LARGER FIELD OF VIEW THAN HRUBY LENS

LESS MAGNIFICATION

Image of the Left Optic Disc and Vessels as

Seen With a 90D Lens and Slit Lamp. The

Image Seen is Inverted and Perverted. The

Magnification is Reduced, but the Field of

View is Large.

Direct View of the Left Optic Disc As Seen

With a Non-Contact Hruby Lens and Slit

Lamp. It Shows Increased Magnification and

Reduced Field of View.

Anatomical, direct view of Dr. Riley's right

posterior pole.Indirect, condensing lens view of Dr. Riley's


6/15

right posterior pole.

78D lenses indirect field of view of the right optic disc and vessels.

Slit Lamp Aspheric Indirect Biomicroscope Procedure

1.) Make sure your patient is comfortably adjusted in the slit lamp. Justas though you were going to do a slit lamp examination.

2.) The illumination system and the microscope should be in alignment or

click position and start with slit lamp magnification on 10X.

3.) Tell your patient what you are going to do and why. Have the patient

close their eyes while you adjust the slit lamp for yourself. Open the slit

width to about 2 - 3 mm's. Because of the slit lamps halogen bulbsbrightness, keep the illumination on low.

4.) Have the patient open their eyes, give them fixation instructions andfocus on the centrally retroilluminated pupil. Then pull the slit lamp back

approximately 2 inches.

5.) With the lens between your thumb and index finger place the lensand your index finger against the patients brow. Look around from

outside the slit lamp to make sure the light from the slit lamp is going

through the lens and into the patients pupil.

6.) If the light is going into the patients pupil you are ready to look

through the slit lamp. Slowly pull the slit lamp towards you. If the

surface of the indirect lens is in focus you still have to pull the slit lampback farther. The more the pupil is dilated and the closer the lens is to

the patient's eye the larger the field of view.


7/15

7.) If you have told the patient to look in the direction of the top of yourear the optic nerve head should be coming into view.

8.) You might notice a reflection in your line of sight, this can be greatly

reduced by either tilting the lens slightly, rotating it around its vertical

axis or by placing the illumination system slightly out of click. Make sureif you place the illumination system out of click it is not obstructing your

view from one of the oculars.

9.) To view the superior retina have the patient look up and tilt the lens

in at the bottom an out towards you at the top. It is important to

remember; if the patient is looking up you are observing the superiorretina. The most anterior part of the superior retina will be located in the

inferior part of the lens. If the patient is looking down your are observingthe inferior retina. The most anterior part of the inferior retina will be

located in the superior part of the lens.

Above Is The Peripheral Retina Of The Right The Image Seen Within The 90D Lens Will


8/15

Eye With A Retinal Scar And Vortex

Ampullae Located At 9:30 And 10:00 O'clock

Respectively.

Be Inverted And Perverted With The Most

Anterior Part Of The Peripheral Retina

Located In The Inferior Part Of The Lens.

To View The Superior Fundus TheLens Must Be Tilted in Toward

The Cheek and The Top OutToward The Examiner

10.) To view the inferior retina have the patient look down. You will have

to use your middle or ring finger to retract the upper lid. Tilt the top ofthe lens toward the patient and the bottom out towards you.

To View The Inferior Fundus TheLens Must Be Tilted in Toward The

Brow and The Bottom Out Toward The

Examiner. The Middle or Ring Finger

is Used to Retract The Upper Lid.

11.) To view the nasal or temporal retina you will need to have thepatient look in the direction you are wanting. Rotate the microscope and

illumination system as a unit in the opposite direction to the patient'sgaze allowing you to get slightly farther into the periphery. The lens is

held so it is always perpendicular to the light source.


9/15

Suggested Procedure for Indirect

Biomicroscopy Examination of the

Posterior Pole of the Eye.

The optic nerve head is usually always examined first. The inferior or

superior arcades are examined in the order you feel most comfortablewith and last the macula foveal areas are examined.

As mentioned before, an optic section of the retina is somewhat different

than the cornea. It is nothing more than a very narrow streak of lightsharply focused on a given area. It is not only helpful in determining if an

area is elevated or is a hole, but is beneficial in detecting and diagnosinga central serous detachment of the macula and drusens of the nerve

head. This sharply focus beam of light causes the surrounding area to be

transilluminated bring out detail and extent.

The lenses are going to get dirty and oily from the patient's lashes

brushing against it and your finger prints. Cleaning the lenses: 1.) Rinsethe whole lens off under running tepid water. 2) place several drops ofhard contact lens cleaner on the surface. 3.) Wet your finger and clean

both surfaces. 4.) Rinse the cleaning solution off completely. 5.) Use apaper towel and just blot the excess water off the surface. Do not rub.

There is an anti- reflection coating on the lenses and you will scratch and

destroy the clarity of the lenses. 6.) Finally blot the remaining moistureoff with a tissue.

Find the optic nerve head and look for venous pulsation, physiologicalcupping and C/D ratio. Give the patient instructions and scan the


10/15


11/15

SCARS, PSEUDOHOLES, ETC.

As Requested The Following Are Definitions Or Explanations Of The

Above: From: Dr. Larry J. Alexander's text "Primary Care Of The

Posterior Segment" 2nd Ed.

1.) Papilledema: Can be a life and vision treating condition. Sometimes

referred to as "choked disc" and according to Dr. Alexander "is bestdefined as optic disc edema secondary to increased intracranial

pressure." The condition is usually bilateral though one nerve head mayprogress faster than the other. Given both nerve heads are distended

and confirmed with ultrasonography or neurologic imaging, i.e., CT scan

or MRI scan is a sure sign of increased intracranial pressure creatingpapilledema. The optic nerve sheaths are pushed forward into the

vitreous as well as laterally causing the retina to buckle inward at thetemporal aspect of the nerve head. This buckling is know as Paton's

folds. The disc vessels as they cross the disc margin become obscured as

a result of the swelling and edema. Acute rise in intracranial pressure,e.g., caused by a brain tumor, results in grossly swollen disc, flame

hemorrhages in the nerve fiber layer, engorged veins, lose ofphysiological cupping, cotton-wool spots and loss of venous pulsation or

the ability for it to be induce. Spontaneous venous pulsation is absent in

approximately 20% of normal individuals, hence, spontaneous venouspulsation not being seen is not diagnostic of papilledema. Other causes,

severe hypertension causing papilledema and marked reduction of

intraocular pressure or extremely high intraocular pressure. Color plates22 & 23 plus Figures 3-86, 3-87, 3-88

2.) Pseudopapilledema: Not to be confused with pseudotumor cerebriwhich has bilateral papilledema, but lacks the presence of an intracranial

mass. Pseudopapilledema is often used when the nerve heads appearswollen in the absence of elevated intracranial pressure, vascular

abnormality, or inflammation. It is a blurring of the disc margins not

caused by elevated intracranial pressure. The most classic example ofpseudopapilledema is that caused by hyaline bodies (calcium-like

globular bodies) of the nerve head. Hyaline bodies, often called drusensof the nerve head are usually located anterior to the lamina cribrosa.

Drusens of the optic nerve head have no histiopathologic correlation to

retinal drusens and as such are not age-related other than they toobecome more visible with age. Drusens are spherical refractile structures

and refractile bodies transilluminate (glow) when viewed with the slitlamp and a Hruby lens or hand held indirect funduscopic lenses.

Ultrasound, B-scan, is most helpful in the diagnosis of buried nerve head


12/15

drusens. Drusens of the optic nerve head are inherited and will most likebe found in other family members. This condition can cause glaucoma

like visual field loss and when severe can be visually devastating. There

is presently no treatment for the condition. Color plates 11 & 12 and

Figures 3-51 & 3-52 Patients with marked hyperopia have nerve headsthat appear small and often appear slightly elevated with blurredmargins. The absence of hemorrhages, peripapillary retinal edema, and

venous engorgement are helpful in ruling out papilledema. Inflammatory

optic neuritis (papillitis) may simulate papilledema when it affects thenerve head. Affected patients have marked visual acuity loss and usually

there are cells in the vitreous surrounding the disc. Engorged veins,blurring of the disc margins, and retinal hemorrhages are characteristic.

This inflammation is usually unilateral.

Figure 3-74

3.) Optic Atrophy: "Degeneration of the optic nerve." The atrophy can

be sectoral, partial, or complete. Whenever it occurs patients will haveloss of vision in the corresponding area of their visual field. The optic

nerve head turns a yellowish to a very white color rather than its normal

salmon or pinkish healthy color plus loss of the very small vessels on itssurface. There are a numerous conditions which can lead to atrophy of

the nerve head. Dr. Alexander breaks the condition down into twoprimary causes: Inherited familial optic atrophy: Pages 122-126 Acquired

optic nerve disease: Dr. Alexander further breaks these conditions down

into inflammations of the optic nerve head, which end with the suffix

"itis" and "optic nerve edema" conditions that cause swelling of the opticnerve fibers. pages 126-165. Color plate 36

4.) Neovascularization of the nerve head: Neovascularization resultssecondary to the lack of oxygenated blood. These new blood vessels are

fragile and subject to leakage, fibrosis, and hemorrhages. New vesselformations are not uncommon in advanced diabetic retinopathy though

there are other causes. When neovascularization of the optic nerve head

occurs the new vessels easily grow into the vitreous an leak proteinsometimes causing a haziness to the disc borders. These new vessels are

subject to trauma and posterior vitreous detachments (PVD) that maylead to intravitreous or retrovitreous hemorrhages. Neovascularization on

the disc will face the direction of the hypoxic retina. Diagnosis of thecause is of utmost importance. Color Plates 44 & 46

4.) Posterior Vitreous Detachment (PVD): This topic is not all that

simple. The development of a PVD rarely occurs before the age of 45years, but after that age it seems to occur more frequently in women


13/15

than men. The condition increases with age, with a prevalenceapproximately equal to the person's age over 50 years. The term implies

that the vitreous behind the vitreous base (the most anterior attachment

of the hyaloid membrane to the retina) and the hyaloid membrane

separates from the sensory retina. The hyaloid membrane collapses andthe space between the retina and the membrane contains liquefiedvitreous gel. In most cases, vitreous detachment is classified as a

complete or incomplete PVD. This can be further broken down to with

collapse or without collapse of the vitreous gel. According to Dr.Alexander, clinically the most common seen PVD is with collapse of the

vitreous gel. The hyaloid membrane pulls free from it's attachment to theoptic nerve head and this creates the common annular opacity

(separation of the ring of Gartner from the optic disc) seen floating in

front of the optic nerve head and or retina. See pages 350 & 351 for

photo and schematics of complete and incomplete PVD. Color plate 87

5.) Cystoid Macular Edema (CME): According to Dr. Alexander CMEusually is secondary to fluid seeping into the unusual arrangement of

fibers in Henle's layer, where the internal limiting membrane is the

thinnest. The etiology of the fluid accumulation is sometimes obscure.The macula area is very sensitive to fluid accumulation. Since, the

macula area is involved the patient experiences a reduction in their visualacuity and in some case have slight metamorphopsia and a prolonged

photostress recovery time. There are many ocular conditions which cause

CME, e.g., ocular tumors, ocular inflammations, vaso-occlusive disease,

post cataract surgery (Irvine-Gass syndrome), idiopathic central serouschorioretinopathy, pars planitis, severe carotid or ophthalmic arterydisease, retinitis pigmentosa, YAG laser posterior capsulotomy and

retinal surgery. Fluorescein angiography is the definitive diagnostic test

and the radiating cystoid spaces of CME present a glow simulating thepetals of a flower. Pages 305-306

6.) Central Serous Retinopathy or Idiopathic Central Serous

Chorioretinopathy (ICSC): ICSC is a puzzling condition with transientepisodes of serous retina or pigment epithelial detachments in the

macular area of young to middle-aged individuals who have no commonpredisposing conditions, such as drusens. The condition is usually

unilateral affect males 10 to 1 over females and is more common inwhites than none whites. Typically patients with ICSC will have sudden

onset of unilateral distortion (metamorphopsia), slight loss of central

vision haze over their vision, or slight color perception problems. Thebest overall view of the dome or elevation of the macula is with the

binocular indirect ophthalmoscope. A important characteristic the


14/15

clinician looks for is a color variation within the macula area. The detailsof the dome are best observed using a Hruby or Volk lens and high

magnification. Because of the fluid, the dome can be transilluminated,

using an optic section, which enhances the view. Color plates 75 & 76

7.) Nerve Fiber Layer Changes: Retinal nerve fiber striations are a

routine ophthalmoscopic finding. The nerve fibers can be enhanced by

using the red free (green) filter or the cobalt blue filter of theophthalmoscope. It has been reported that nerve fiber layer defects can

be identified up to 5 years before visual field abnormalities appear. Thestriations are best seen at the inferior and superior aspects of the optic

nerve head. They are most easily seen in young patients and patients

with heavily pigmented fundi (plural for retina). When there isdegeneration of the nerve fiber layer they are usually located or easiest

seen within 2 disc diameters of the optic nerve head. Figure 3-70

8.) Macular Holes: It is considered that any condition that produces

cystoid macular edema may be implicated in the origination of the

macular hole. Idiopathic (a condition of unknown origin or cause)macular holes usually occur in patients over 60 years of age. Macular

holes are usually divided into two separate categories, lemellar holes(partial thickness hole) and full-thickness (through and through

holes).The lemellar hole is the result of the rupture of the thin, inner

retinal layer of a macular cyst. There is a slight reddish coloration or thehole with some retention of visual acuity. A full-thickness hole is a

complete loss of retina neural (sensory) tissue. It is usually 1/3 to 1/4disc diameters (DD) in size, reddish in color and surrounded by a grayish

edematous cuff of tissue. There are usually yellow deposits in the base of

a full-thickness hole, however, they may be transitory. Figures 5-35 & 5-36 plus color plates 77 & 78

9.) Pseudomacular Hole: Pseudomacular holes may be the result of the

contraction of the epiretinal membranes with a baring of the tightlybound foveal area. The illusion of a macular hole may be created by the

contrast of the whitish epiretinal membrane and the foveal color whichcreates a sharply circumscribed border around the foveal area.

Pseudoholes are usually oval and appear puckered rather than round,lack the presence of yellow deposits in the base, and edematous cuff of

neural tissue. Careful examination with the slit lamp and fundiscopic

lenses makes the differentiation easier plus the presence of the whitishepiretinal membrane. The pseudohole may reduce the patients visual

acuity as a result of the tugging on the neuro tissue in the foveal area.


15/15

PERIPHERAL FUNDUS OF THE RIGHT EYE

The short ciliary nerves are usually located near a vortex ampullae whichare located at the equator of the eye. Vortex ampullae are very easy to

see in blond, light colored eyed patients. This is not always the case insome patients where the only clue you are near a vortex is the presence

of pigment migration at and around its base.

You will be asked to find some of the above structures with these lenses.The optic nerve head, venous pulsation, C/D ratio, macula, vortex veins,

short ciliary nerves are areas you should be able to find and observe.

AppendixThe latest lenses Volk has add to the hand held funduscopic lenses are

the Super Field and more recently the Super Pupil and the Super 66. TheSuper Field is approximately the same the size as the 60 or 78D lenses.The company claims it has the magnification close to the 78 and the

visual field size closes to the 90D lens 30-40 degrees. Because of it's sizeI find it has one of the drawbacks the 78D lens, e.g., when examining the

extreme peripheral retina it is more difficult to maneuver within theorbital area. I like the lens it has excellent optics and you will most likely

find you can become proficient with any of the lenses. The Super Field

must be held correctly unlike the 78, 60, and 90D lenses which eitherside may face the patient. The Super 66 is approximately the size of the

Super Field with magnification between the 78 and 60 diopter lenses. Ihave not used the Super Pupil. It claims to get a binocular view of the

disc of an undilated pupil. Therefore, you will have less magnification, but

will have a lager field of view.

fundus lens

Documents