Slit Lamp

<Procedures>

<Index>

 

 

-  Foreign Body Removal

 

Definition

-  Binocular microscope providing stereoscopic view of the eye

 

Features

-  Exam of eye with slit of light which can be adjusted (height & width)

-  Accentuates anatomy

-  Magnification x10-25

-  Less useful for posterior segment of eye: vitreous, fundus, optic disc

 

Rationale

-  Acute conditions requiring magnification of anterior segment of eye

-  Lids, lashes, conjunctiva, cornea, anterior chamber, iris, lens

-  Occular foreign body removal

-  Evaluation of red eye

-  Dx of

-  Corneal epithelial defect

-  Keratoconjunctivitis

-  Hyphema, hypopynon

-  Lens dislocation

-  Herpetic dendritic ulcers

-  Iritis

 

Cautions/Contraindicatons

-  Open globe injury

-  Caustic exposure: irrigation & normal pH prior to exam

-  Globe movement during foreign body removal

 

Equipment

-  Topical anaesthetic ie: Proparacaine

-  Fluorescein strip

-  Gauze &/or tissue

-  +/- contact lens removal device

-  +/- 18G needle to foreign body removal

-  Slit Lamp

 

 

Preparation

-  External eye exam

-  Visual acuity

-  Cranial nerve exam

-  Ask about contact lenses

-  Fluorescein permanently stains

-  Darken room

-  +/- use of topical anaesthetic ie: Proparacaine

-  If eye pain +/- blephorspasm interferes w exam

-  All topical agents cause transient pain

-  Slit Lamp Setup

-  Examiners chair to comfort

-  Loosen lock nut on slit lamp assembly

-  Set lenses to 0

-  Adjust binoculars

-  Patient chin on chin rest

-  Adjust table height for pt comfort

-  Focus Slit Lamp

-   Create tall, narrow vertical beam of light

-   Direct beam to bridge or pts nose at 45o temporal to nasal

-   Move entire assembly (coarse focus) to bring light into sharp focus externally

-   Use binoculars & joystick (fine focus) to obtain crisp image

 

Procedure

-  Examine lids, lashes, conjunctiva, cornea, anterior chamber & lens

-  Lower lid, lashes & conjunctiva

-  View lower lid w cotton tip to assist

-  Pull down lid w cotton tip to view palpebral conjunctiva

-  Upper lid, lashes & conjunctiva

-  Patient to look down

-  Eversion of the lid

-   Cotton tip horizontally along fold of upper eye lid

-   Roll down to evert lashes

-   Grasp lashes, pull out then upward

-   Use cotton tip as fulcrum

-   Hold in position w thumb

-   To release pt to look up & blink

-  Cornea

-  Magnification to low power

-  Focus of corneal epithelium

-  If lesion detected switch to high power

-   Infiltrate

-   Oedema appears as wrinkling

-   Keratic precipitates of red or white cells on endothelial surface

-  Fluorescein exam

-  Wet Fluorescein strip w single drop saline or anaesthetic

-  Pull down lower lid, pt to look up

-  Touch tip to lower conjunctival fornix

-  Pt to blink

-  Select cobalt blue filter w wide slit beam & low power magnification

-  High power to examine lesions

-  +/- Siedels Test

-  For microperforation

-  Topical anaesthetic

-  Fluorescein w several drops

-  Low power

-  Small perforation = clearing of dense Fluorescein streaming away from site

-  If positive --> eye shield --> prompt opthalmologist

-  Cells & flare

-  Darken room as much as possible

-  Short wide slit beam

-  Center beam on central cornea

-  Focus between iris & corneal epithelium

-  Flare = headlight beam in fog

-  Cells = sparkles of light

-  Foreign Body Removal

-  Topical anaesthetic

-  Requires maximal pt compliance

-  Rest hand on pt cheek to stabilize hand

-  Directly observe needle to within 3-5mm of eye

-  Observe device through binoculars

-  Advance under magnification

-  Scrape tangentially to cornea

-   No need to be aggressive

-  Residual materaial (rust ring..) removed 24hr+ later

 

Complications

-  Globe perforation during foreign body removal

-  Corneal abrasion from foreign body removal

-  Allergic reaction to Fluorescein or topical anaesthetic

 

 

 

References

 

Upto Date: Slit Lamp Examination (incl pic)