Topical Ophthalmic Dyes And Special Procedures for Biomicroscopy

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Topical Ophthalmic Dyes And Special Procedures
for Biomicroscopy

• Laura A. Falco, OD FAAO
• x1452

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Required Readings

• Atlas of Primary Eyecare procedures pp.42-6
• Clinical Procedures in Optometry (Eskridge,
  Bartlett, Amos) pp358-63
• Borish, Chapter 13

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Topical Ophthalmic Dyes

• Purpose Evaluate integrity of the cornea,
  conjunctiva and tear film
• Numerous Dyes have been used
• Rose Bengal
• Methylene Blue
• Trypan Blue
• Alcian Blue
• Lissamine green
• Fluorescein

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History

• Fluorescein first made by Baeyer in 1871
• Used in 1882 and 1888 for epithelial defects and
  in the anterior chamber (By Pfluger and Straub)
• 1910 Burk used it to detect retinal disease

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History

• Rose Bengal was made by Gnehm in 1882 and was
  used as a corneal stain in 1914 by Romer, Gebb
  and Lohlein.
• 1933 Sjogren (show-gren) described the use of
  rose bengal for revealing corneal abnormalities
  and abnormal tear film with keratoconjunctivitis
  sicca (Sjogrens Disease)

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Using Fluorescein Clinically

• Applied Topically to help detect
• Breaks in the corneal epithelium
• Punctate epithelial erosions
• Abrasions
• Ulcers
• Foreign Bodies
• TBUT
• Seidel Signs

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contd

• Management of Contact lenses
• Evaluation of the lacrimal system (Jones Dye
  tests I and II)
• Applanation Tonometry

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Rose Bengal

• Clinically used to detect
• Dead/Degenerative tissue on the cornea and the
  conjunctiva.
• Will selectively stain only devitalized cells, it
  can be used to help diagnose k-sicca, Herpetic
  Eye disease (simplex keratitis),
• Punctate epithelial keratitis
• Filamentary keratitis
• Exposure Keratitis

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Fluorescein

• Under white light will look yellow-orange
• Under cobalt blue it fluoresces to produce a
  green-yellow light.
• Fluorescence ability of certain substances to
  absorb light of certain wavelengths and emit
  light at longer wavelengths.

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In White Light
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With cobalt blue filter
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How Fluorescein works

• It cannot penetrate the cell membranes of the
  epithelial cells nor the zonula occludens (tight
  junctions between epithelial cells) but it shows
  breaks in the cellular spaces. With epithelial
  loss, the dye can spread into the stromal tissue
  and even enter the anterior chamber where it
  appears as a green aqueous flare.

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How Rose Bengal Works

• Rose bengal stains mildly degenerated corneal and
  conjunctival cells a light bluish red, severely
  degenerated cells appear dark red and dead cells
  become an intense red The intensity of the color
  make it easy to identify devitalized cells of
  both the corneal and conjunctival epithelium.

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Rose Bengal Stain in white light
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Clinical Interpretation of FL staining

• A wide range of diseases will produce various
  Fluorescien staining patterns
• Here are a few examples
• Diffuse Staining Bacterial Viral
  Conjunctivitis, Medicamentosa (iatrogenic),
  Allergic keratoconjunctivitis
• Upper 1/3rd stain characteristic of certain
  diseases , eg. Trachoma

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Contd

• Interpalpebral exposure con-itis, UV Lower
  2/3rd Staph Blepharitis, ectropion,
  lagophthalmos, exposure keratitis
• Linear Streak mechanical abrasion, trichiasis,
  entropian, foreign body

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Contd

• Sectorial Trichiasis, trauma
• Dendritic Herpes Simplex

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Senile Entropian
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TBUT

• Tear Break Up Time (TBUT)
• The tear film has 3 main layers
• outer lipid layer
• middle aqueous layer
• inner mucin layer
• The lipid and mucin layers serve as the aqueous
  layer protection from evaporation, therefore
  keeping the eye moist and hydrated.

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TBUT

• Problems with the lipid or mucin layers will
  result in the aqueous layer evaporating, the
  precorneal tear film will dry out and the patient
  will complain of dry, burning eyes.
• Aqueous problem -- Decrease in tear production
  (lacrimal gland problem) will also cause dry eye
  complaints.

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TBUT

• When staining the cornea with NaFl, dry areas
  will appear as black spots/streaks against a
  solid green glow.
• The amount of time it takes for dry areas to form
  in the stained tear layer following a blink is
  known as the tear breakup time (TBUT).

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TBUT

• Normal time elapsed before a black spot (dry
  area) appears 15 seconds. A greatly reduced
  TBUT is indicative of Dry eye disease. Less than
  10 seconds is considered reduced
• Perform TBUT during your slit lamp examination
  when the history indicates a need for it based on
  complaints.

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TBUT

•         TBUT should be performed prior to
  instillation of any topical anesthetics/dilating
  agents
•          If patient has problems refraining from
  blinking, hold their lids
•          The area the NaFl strip touched (bulbar
  conj.) will stain brightly, do not worry about
  thisiatrogenic

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TBUT

•          Do not instill NaFl in a patient that is
  wearing contact lenses
•          This dye can stain lenses, so rinse out
  patients eyes before re-inserting contacts.

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Clinical Interpretation of Rose Bengal Staining

• Mainly used when suspecting dry eye disease
• Used to see corneal dessication, caused by
  lagophthalos, facial nerve palsy, ectropion,
  exophthalmos, ptosis surgery
• Helps in filamentry keratitis, stains dessicated
  epithelial cells and mucus that are attached to
  the cornea

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Rose Bengal

• Herpes Simplex Keratitis Rose bengal will stain
  brightly stains the damaged epithelial cells on
  the ulcer border. Sometimes a lesion will not
  stain with Fluorescein, but will with rose bengal
  because the epithelial lesion has healed, but the
  devitalized cells are still present

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Instilling NaFl

• Remove NaFl strip from package
• Hold over Sink and saturate the end with sterile
  saline
• Have patient look up
• Pull down patients lower lid and instill drop on
  the lower bulbar/palpebral conjunctiva

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Contd

• Let go of lid and go over to the other eye unless
  contraindicated (infection)
• Educate the patient that their tears may look
  gold/yellow for 10 minutes (with NaFl)
• Be careful this dye stains, it will stain
  clothes, fingers, faces, etc.

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Counting TBUTTear Break-Up Time

• Align patient in slit lamp
• Introduce Cobalt Blue filter
• Check for corneal integrity
• Instruct patient take a nice hard blink and then
  hold your eyes open.
• Always be scanning the entire cornea
• Count seconds in your head until the first black
  streak (area appears)

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Contd

• Done before any anesthetic applied
• Paradoxical findings may require re-testing with
  topical anesthetic
• Elevated epithelium may always look black
• Schirmer Strippaper strip
• Zone Quick ---string

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Instilling an Eyedrop

• Remember..
• Always Wash Hands
• Instruct patient to tilt their head back and look
  up to the ceiling
• Give patient a tissue before you put a drop in
  their eyes

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Biomicroscopy Special Procedures

• Review lecture notes and lab manual from last
  semester for basic slit lamp skills
• The biomicroscope produces 7 configurations of
  illumination.
• These are Direct, sclerotic scatter, retro,
  specular reflection, indirect (or proximal),
  diffuse, and tangential. (Eskridge et al., 1973)

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Which illumination to use?

• Dictated by the structure needed to be visualized
• Certain abnormal conditions are visualized best
  with certain illumination
• Review Direct illumination- the biomicroscope
  and the light source are coincident (focused at
  the same point)

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Contd

• Direct..depending on what needs to be seen, a
  variety of slit widths and angles of the light
  source can be used.
• Examples parallelopiped, optic section-used to
  see things in cross section- cornea, lens

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Sclerotic Scatter

• Illumination of the limbus while the cornea is
  examined
• Used to reveal central corneal edema, central
  corneal haze, scarring, and gross view if the
  angle is open
• Exact set-up is in lab manual,
• Two observations, one in slit lamp, one outside
  of slit lamp

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Retroillumination

• Examines structures from behind
• Shine light through the pupil and see if the iris
  glows anywhere revealing defects
• Using retro can also enable us to see media
  opacities of the cornea, lens or vitreous.

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Indirect (or Proximal)

• Method to transilluminate structures adjacent to
  the slit beam.
• The light source is focused adjacent to the area
  you are interested in viewing
• Most useful anteriorly for iris-surface
  observation

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Specular Reflection

• Used when you need to visualize the most
  posterior layer of the cornea.The Endothelium
• The slit beam is taken out of click and the
  examiners focus is directed to the bright beams
  reflection at the layer of interest
• This procedure is difficult to do and highest
  magnification 25X is needed

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Contd.

• This view will highlight the endothelial cells
• Honeycomb appearance
• Alligator shoes

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Tangential Illumination

• Used to view the iris
• The beam and the oculars are at right angles to
  each other
• Used to examine contact lens fits

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Lens Evaluation

• Best seen through a dilated pupil
• Light source angled
• Oculars straight ahead
• Want to focus in the middle of the pupil
• Parallelopiped/optic section
• Lens is composed of layers
• Anterior lens capsule is the closest to the pupil

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Contd

• Anterior lens capsule has a orange-peel
  appearance
• Y-suturescentral nucleus
• Posterior lens capsule
• Resembles layers of an onion

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Vitreous Evaluation

• Same position as with lens eval, push joystick
  forward and head into vitreous
• Optically empty
• Black
• Have patient look up and then straight ahead
• Look for strands floating within area
• Posterior Vitreal Detachment (PVD)

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Direct Ophthalmoscopy

• Assigned reading page 186 Atlas of Primary
  Eyecare procedures (Fingeret)
• Coaxial field of view (10)
• Panoptic field of view (25)
• Enhance your field of view by
• Dilating patient
• Decreasing distance to patient (coaxial)

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Direct O.

• Magnification
• Standard mag. (coaxial) 15X ( virtual,erect
  image)
• Myopes have more magnification
• Hyperopes have less magnification

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Direct O.

• Filters
• Spot
• Streak/slit
• Red-Free filter enhances the contrast of
  structures/lesions containing blood or pigment,
  also enhances the appearance of the nerve fiber
  layer

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Develop an Approach

• Want to keep a systematic approach on all
  patients
• Evaluate
• Media
• Disc margins (pink, distinct, pale)
• Spontaneous venous pulse
• Vasculature (a/v ratio)
• Macula/Fovea
• Fundus backgrounds

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Direct O

• Advantages
• Easy to master
• Greatest patient comfort
• Used with small pupils
• Most accurate estimate of the patients visual
  compromise due to media opacification

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Direct O

• Disadvantages
• Limited illumination
• Lack of stereo
• Close working distance
• Dependence on refractive error for clarity and
  magnification
• Small field of view

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Assigned Readings

• From Atlas of primary eyecare procedures
  (Fingeret)
• Direct O.. Pp.186-187
• Von Herrick estimation Pp. 26-27
• Tbut and staining 42-49, 108-111
• Tonometry.. Pp. 50-62
• Slit lamp spec. proced 62-72

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More Assigned readings

• From Borish,
• Chapter 14, Direct O Pp. 430-438
• Chapter 13, (all) slit lamp with special
  procedures
• Any handouts given in class can be tested and is
  considered required reading