GONIOSCOPY
DR MD FERDOUS ISLAMCMH, Dhaka
HISTORY
• Greek gṓ nḗ : angle , Ộs’k-pḗ : view• Alexois Trantas (1907) First visualized angle in an eye with
Keratoglobus
• Maximilian Salsmann (1914) Father of Gonioscopy First introduced Goniolens
• Koeppe Designed improved contact lens and gave the method
biomicroscopy of angle of anterior chamber with slit lamp
• Manuel Uribe Troncoso Developed gonioscope for magnification & illumination
of angle First to write a comprehensive book on gonioscopy
• Otto Barkan Established use of gonioscopy in
management of glaucoma
• Goldmann (1938) Introduced gonioprism
PRINCIPLE
• Critical Angle
INDIRECT DIRECT
CONTACT LENSES FOR GONIOSCOPYDIRECT
LENS DESCRIPTIONKOEPPE Prototype Diagnostic LensRICHARDSON SHAFFER Small Koeppe Lens used for
InfantsLAYDEN For Gonioscopic Examination of
Premature InfantsBARKAN Prototype Surgical GoniolensTHORPE Surgical & Diagnostic lens for
Operating RoomsSWAN JACOB Surgical Goniolens used in
Children
KOEPPE
INDIRECTLENS DESCRIPTION
GOLDMANN SINGLE MIRROR Mirror inclined at 62 degreesGOLDMANN THREE MIRROR One mirror for gonioscopy, two for retina;
coated front surface for laser useZEISS FOUR MIRROR All 4 mirrors inclined at 64 degrees for
gonio;requires holder;fluid bridge not required.
POSNER FOUR MIRROR Modified Zeiss four mirror gonioprism with attached handle
SUSSMAN FOUR MIRROR Handheld Zeiss type GonioprismTHORPE FOUR MIRROR Four gonioscopy mirrors; inclined at 62
degrees;requires fluid bridgeRITCH TRABECULOPLASTY LENS
Four gonioscopy mirrors; two inclined at 59 degrees & two at 62 degrees with convex lens over two
LATINA TRABECULOPLASTY LENS
One mirror for Trabeculoplasty
GOLDMANN THREE MIRROR
ZEISS FOUR MIRROR
• All 4 mirrors inclined at 64 degrees
SUSSMAN FOUR MIRROR
THORPE FOUR MIRROR
• Four mirrors; inclined at 62 degrees
RITCH TRABECULOPLASTY LENS
LATINA TRABECULOPLASTY LENS
• One mirror for Trabeculoplasty
INDIRECT TECHNIQUE
DIRECT
ADVANTAGE
• Observer’s height can be changed
• Done on sedated, comatose & Children
• Panoramic view of Angle• Less distortion of AC• Useful in examining fundus
with small pupil
DISADVANTAGE
• Inconvenient• Special equipments
required• Difficult to master• Does not stabilize globe
INDIRECT
ADVANTAGE
• Quick & convenient• No special equipment
required• Allows differentiation between
appositional & synechial closure
• Can create corneal wedge
DISADVANTAGE
• Inadvertent pressure on cornea
• Mirror image is confusing
DIRECT V/S INDIRECTDIRECT
• Panoramic view of iridocorneal angle with ability to adjust view by examiner
• Both eyes can be examined simultaneously
• No viscous [ coupling ] material required
• Direct view for surgery e.G. Goniotomy
• DISADV: inability to perform indentation, low magnification, assistance
INDIRECT
• Segmental view
• One eye at a time
• Viscous required
• Mirror image seen• Excellent optics with slit
lamp• Indentation can be done
INDICATIONSDIAGNOSTIC Classification : open or closed angle glaucoma To assess AC angle recess & risk of angle closure To identify plateau iris To look for abnormal angle pigmentation, PXF , angle recession, cyclodialysis, foreign body, Neoplasm, copper deposition , blood in Schlemm’s canal
Evaluation of trabeculectomy fistula , glaucoma drainage devices
Congenital anomalies- aniridia, iris processes
THERAPEUTIC
Laser trabeculosplasty/ goniophtocoagulationGoniotomy/ Gonioplasty/ Trab Reopening of blocked trabeculectomy openingLaser of suture around tube of G.D.D.Indentation gonioscopy to break an attack of acute
ACG•
NORMAL ANGLE STRUCTURES
CILIARY BODY BAND
• This structural portion of ciliary body is visible in the A.C. as a result of iris insertion into ciliary body
• Width depends on level of iris insertion
• Wider in myopes and narrow in hyperopia
• Color: grey to dark brown
SCLERAL SPUR
• This is the posterior lip of scleral sulcus which is attached to the ciliary body posteriorly and corneo-scleral meshwork anteriorly
• Color : prominent white line
TRABECULAR MESHWORK• Pigmented band anterior to scleral spur• Although extent of TM is from root of iris to schwalbe’s line it
is considered as 2 portions
a) Anterior - between schwalbe’s line and anterior edge of schlemm’s cannal• Involved in lesser degree of aqueous out flow
b) Posterior – Functional part , primary site of aqueous out flow
• Appearance of funtional TM depends on amount of pigment deposition
TRABECULAR MESHWORK
• At birth no pigment and with age from faint to dark brown
• Pigment deposition may be homogeneous or irregular
CORNEAL WEDGE
• When a thin slit of light hits the irido-corneal angle at an angle of 10⁰-15⁰, two light reflections are seen from the external and internal corneal surfaces which pipe down at the sclero-corneal junction (Schwalbe’s line) marking the anterior border of TM
• Corneal wedge is a useful technique to identify the TM in eyes that are either non pigmented or excessively pigmented its diff. to mark TM begins
SCHWALBE LINE
• Junction between anterior chamber angle structures and cornea where the descement’s membrane terminates
• Fine ridge ant. to TM identified by a small built up of pigment
• Landmark for TM in narrow angle
SAMPAOLESI'S LINE
POSTERIOR EMBRYOTOXON
ANGLE BLOOD VESSELSNORMAL
• Radial Orientation• Thick• Non Branching• Do not cross Scleral Spur
NEOVASCULARIZATION
• Fine• Arborising• Crosses Scleral Spur
MANUPULATIVE GONIOSCOPY
• Over the Hill• Corneal Wedging• Indentation
OVER THE HILL/DIVE BOMBER’S VIEW
• It’s a special maneuver to view over a steep iris
• It is done by asking the patient to look in the direction of the mirror or moving the mirror towards the angle being viewed
INDENTATION GONIOSCOPY
• When iris covers the trabecular meshwork (TM) its easy to mistake:– The non-pigmented TM for scleral spur–Pigmented Schwalbe’s line for TM–Apposition from synechiae
• Indentation Gonioscopy is particularly useful in these cases
• Useful when iris surface is convex–Done when recognition of angle structures
is difficult• Performed in all glaucoma cases–Differentiates appositional vs synechial
closure in pupillary block–Measures extent of angle closure– Identifies plateau iris config– Identifies lens induced angle closure
STERILIZATION & DISINFECTION
• Wash with soap & water• Soaking the lens for 5-10 min in fresh solution of
Sodium Hypochlorite [ 1:10 household bleach : water]• Rinsing with sterile water• Air drying• 3% H2O2 or 1% Formaldehyde can also be used• Direct surgical gonioscope [ Koeppe, Swan Jacob] can
be sterilized with ethylene oxide
LIMITATIONS
• Contact investigation patient discomfort• Conjunctival infection• Artefactual angle closure• Slit lamp illumination-> pupil constriction-> opens up
the angle• Wide interobserver variations• Indentation corneal folds, distorted view of angle
structures, epithelial injury
CONTRAINDICATION
• Painful inflamed eye
• Acute glaucoma with edematous cornea
• Mydriatic drugs- obscure angle by bunching up iris
• Suspected open globe injury or early in course of suspected closed globe injury with hyphaema as pressure may precipitate rebleeding
REF
• American Academy of Ophthalmology• Clinical Optics by A R Elkington• Kanski’s Clinical Ophthalmology by Brad Bowling• Google