Gonioscopy Wet-Lab. About Me. About Me Gonioscopy. Indications for Gonioscopy. Billing Gonioscopy 12/13/2012. Code: 92020

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1 About Me Gonioscopy Wet-Lab Marcus Gonzales, OD, FAAO Cedar Springs Eye Clinic (formerly BridgeBuilders Eye Clinic) About Me Gonioscopy Evaluates the anterior chamber angle responsible for the outflow of aqueous Indications for Gonioscopy Narrow angles Asymmetric IOPs Secondary open angle glaucomas Complications from retinal conditions Iris anomalies Trauma Code: Billing Gonioscopy Medicare Allowable: around $26 Most already own gonio lens No additional special equipment 1

2 Contraindications/Cautions Corneal surface conditions Recent trauma Hyphema Globe perforation/laceration Chronic acute inflammatory conditions Types of Gonioscopy Direct gonioscopy Lens refracts light to evaluate angle directly Recumbent position More common on children Indirect gonioscopy Lens has mirrors to evaluate the opposite angle Most common method of visualizing the angle Gonio Lenses Flange 3 or 4 mirror lenses Advantage: easier to master, stable, excellent view Disadvantage: cushioning agent, bulky, no compression, more time, less comfortable Gonio Lenses Non-flange 4-mirror lenses Advantage: no cushioning agent, smaller, compression, quicker, more comfortable Disadvantage: learning curve, variable view depending on patient Grading Systems Shaffer Scheie Spaeth 2

3 Contour of the iris Deepest structure Keep It Simple! Trabecular meshwork pigmentation Angle characteristics Technique Systematic approach Remember why you re doing this Don t use too much light Don t use too large of a beam height Don t use too much magnification Don t panic!! Educate the patient Clean lens Prep Work Betadine and alcohol Soap and water Disinfectant solution Instill anesthetic Apply cushioning agent if necessary Methylcellulose, Boston Conditioning Solution Procedure Flange Lens Direct gaze downward and hold upper lid Direct gaze upward and pull lower lid down Rock lens forward onto eye Direct gaze toward straight ahead and center the lens on the cornea 3

4 Procedure Non-flange Lens Hold superior and inferior lids open Focus SLE on anterior corneal plane Slowly place lens on the eye while looking through the oculars Center the lens on the cornea maintaining an even water seal SLE Settings Housing unit: 0-10º off-axis Beam orientation: small, vertical Illumination: dim to medium Magnification: start with medium (10-16x) Systematically evaluate each quadrant Rotate the lens for 360º evaluation Remove Lens Direct gaze toward nasal side while holding lens Apply pressure on temporal lower lid toward the lens Corneal Folds Bubbles Pitfalls Generalizations Superior angle is narrowest and inferior angle is the deepest Myopes have deeper angles compared to hyperopes Asians have a higher incidence of narrow angles World Glaucoma Association Von Herrick very predictive of angle depth Evaluating the Angle Contour of the iris Deepest structure Trabecular meshwork pigmentation Angle characteristics 4

5 Contour of the Iris Angle Structures Convex - S Flat - R Concave - Q Trabecular Meshwork Pigmentation Gradings: 0 Trace no pigmentation very little pigmentation mild pigmentation moderate pigmentation marked pigmentation Normal Angle Normal Angle ATM SL Flat ATM 1+ PTM SS CB Flat 2+ PTM SL 5

6 Normal Angle Difficult Angles No TM pigmentation Scattered TM pigmentation Lots of TM pigmentation Narrow angle ATM SL 3+ PTM Techniques: CB Flat SS Corneal Wedge/Ledge Compression/Indentation Corneal Wedge/Ledge No TM Pigmentation Normal Angle Scattered TM Pigmentation 2+ PTM CB 6

7 Lots of TM Pigmentation Compression Type of Closure Appositional Closure Appositional Synechial Appositional Closure Appositional Closure 7

8 Synechial Closure Synechial Closure Angle Characteristics Iris processes Peripheral Anterior Synechiae (PAS) Sampaolesi s line Recession Iris Process vs PAS Iris Process Thin, small string Usually attaches to the SS and TM Pushes back with compression PAS Thick, broad band Usually attaches to the TM and cornea Doesn t push back with compression Iris Process Iris Process 8

9 Peripheral Anterior Synechiae (PAS) Peripheral Anterior Synechiae (PAS) Peripheral Anterior Synechiae (PAS) Sampaolesi s Line Sampaolesi s Line Angle Recession 9

10 Angle Recession Angle Recession Pearls Use a systematic approach Utilize corneal wedge/ledge technique Utilize compression technique Practice on normals Go learn at. Thank you for your attention Questions? 10