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