What Am I Seeing?: Answers to Gonioscopy Questions Nate Lighthizer, O.D., F.A.A.O. Associate Professor, Oklahoma College of Optometry Assistant Dean of Clinical Care Chief of Specialty Care Clinics Chief of Electrodiagnostics Clinic Director of Continuing Education [email protected] Material provided, in part, by Dr. Doug Penisten Angle Anatomy “I Can’t See This Sh@%” Iris Insertion Ciliary Body (Band) Scleral Spur Trabecular Meshwork Schwalbe’s Line Gonioscopic view History of Gonioscopy How do you see the angle? Use either Direct lens – use a contact lens with specific anterior curvature that will overcome critical angle Indirect – use a mirror to overcome the critical angle Direct Gonioscopy Koeppe lens is the gold standard in direct gonioscopy Usually used for pediatric patients in association with a hand held slit lamp (gonioscope + focal illuminator) Provides 15X to 20X mag Indirect Gonioscopy Two major types Goldmann Three Mirror lens Zeiss four-mirror lens AKA Posner AKA Sussman without the handle Gonioscopy Is the gold standard for assessing the drainage apparatus of the eye Gonioscopy should be performed on all patients at least once a year? CPT code 92020…MCR reimb = ~$25 Gonioscopy Used to distinguish one type of glaucoma from the other Mainly open from closed angle glaucoma Also angle recession and others Optics of Gonioscopy Instructing and Counseling the Patient “Why and How” Preparing the Lens Insertion Techniques Types of Goniolenses 6 mirror lens! Indentation Gonioscopy Laser peripheral iridotomy (LPI) How likely is this patient to develop glaucoma? How do we predict whether she will progress? How effective is LPI? What do we do if LPI fails? Iridotomy indications Acute angle closure glaucoma Asymptomatic angle closure glaucoma Prophylaxis for primary angle closure suspect (“narrow angles”) How narrow is too narrow? How aggressive should we be? How do we measure the angle? Gonioscopy vs newer technologies (i.e. anterior segment OCT) Gonioscopy Advantages: view synechiae, angle recession, pigment levels, NVA Disadvantages: subjective CTAS-O Advantages: objective, noninvasive Disadvantages: no view of pigment, synechiae, NVA How do we measure the angle? Gonioscopy: Underutilized, according to chart review studies and Medicare billing data Remains gold standard for angle measurement How do we classify the angle? Based on chronicity Acute Subacute Chronic Based on glaucomatous damage Primary angle closure suspect Primary angle closure Primary angle closure glaucoma Additional concepts: intermittent, latent, creeping angle closure A Simplified Classification Scheme 1. Anatomically narrow (PACS) – Indentation gonioscopy opens angle – Normal IOP – Heightened suspicion 2. Anterior synechiae and/or elevated IOP (PAC) – Minimal natural history data 3. Closed angles and glaucomatous damage (PACG) (Fourth category: Acute symptomatic angle closure) How narrow is too narrow? Gonioscopy: iridotrabecular contact in at least 180 degrees Iridotrabecular contact = failure to see posterior meshwork AS- OCT: angle opening is less than 5-10 degrees Visante: use lens vault measurement A Simplified Classification Scheme 1. Anatomically narrow (PACS) – Indentation gonioscopy opens angle – Normal IOP – Heightened suspicion 2. Anterior synechiae and/or elevated IOP (PAC) – Minimal natural history data 3. Closed angles and glaucomatous damage (PACG) (Fourth category: Acute symptomatic angle closure) When to recommend prophylactic LPI Narrow angle (next slide), and presence of any: Peripheral anterior synechiae Elevated IOP Optic nerve damage Family history Narrow angle without any of these: discuss risks, involve patient in decision Slit-Lamp Setup Tips on Set-up Position mirror at 12:00. (I always view inferior angle first to get my landmarks.) To begin, keep gonio lens oriented straight (i.e., not tilted) Put light on mirror before you go to the oculars. I rest my hand on the patient’s head. Elbow rest if needed. Appreciating and Anticipating the Anterior Chamber Morphology Start with the “Big View” First Low Mag and Iris Conformation Illuminating the Angle Optical “Corneal Wedge” Getting the Wedge and Variations of the Wedge Presentation Set-up for Wedge Illumination very bright Slit very narrow and vertical Move illumination angle a few degrees to the right or left. (Not straight ahead) May have to move light left or right until optimal position found. Most clinicians will view the optical “corneal wedge” once – in the inferior angle. Using the landmarks found in the inferior angle, the other three quadrants can be evaluated. If needed, the wedge can also be viewed in the superior angle. (Cannot be done in lateral angles) Angle Anatomy “Clinical Variations on a Theme” Angle Anatomy Iris Insertion Ciliary Body (Band) Scleral Spur Trabecular Meshwork Schwalbe’s Line Ciliary Body (Band) Visibility – “Width” Pigmentation Scleral Spur Trabecular Meshwork Schwalbe’s Line Identifying Angle Structures – Two Basic Techniques Posterior to Anterior Anterior (Optical Wedge) to Posterior Quiz Time – 3 presentations What’s the most posterior structure seen? A. Schwalbe’s line B. TM C. Scleral spur D. CB band What’s the most posterior structure seen? A. Schwalbe’s line B. TM C. Scleral spur D. CB band What’s the most posterior structure seen? A. Schwalbe’s line B. TM C. Scleral spur D. CB band Recording Your Findings St. Andrew’s Cross Essential Findings to Record Most Posterior Anatomical Feature of Angle Seen Rating of Angle Conformation, i.e., the Angle “Openness” Other Significant Findings, ex., pigment Rating of Angle Conformation Spaeth’s angular width of the angle recess Spaeth’s configuration of the iris OR Steep (s) Regular (r) Queer (q) Spaeth’s insertion grading Pigmentation Spaeth grading B15b 2+ptm Trabecular meshwork (B) 15 degree angle Anterior bowing of iris (b) 2+ pigment in tm (2+ptm) Describes open but somewhat narrow angle with moderate pigmentation and a bowed iris Shaffer classification Techniques for Removing Lens Different Angle Presentations What is the most common cause of narrow angle glaucoma? A. Plateau Iris Syndrome B. Pupillary Block C. Malignant Glaucoma D. POAG E. Phacomorphic glaucoma Pupillary Block vs. Plateau Iris Syndrome Plateau Iris Syndrome Development of residual angle closure after patent Laser Peripheral Iridotomy (LPI) Flat iris plane Deep anterior chamber Narrow angle due to anterior insertion of iris root Dilation, being in a dark environment often promotes bunching of peripheral iris in the angle Consider the demographics 20 -50 year old Caucasian females seem to be the most prominent demographic Plateau Iris Syndrome Angle Recession Angle recession Pigment Dispersion Syndrome Pigment dispersion Peripheral anterior synechiae Quiz Time – 3 presentations What would you record? A. Schwalbe’s line – 1+ pigment B. TM – 1+ pigment C. Scleral spur – 1+ pigment D. CB band – 1+ pigment Iris processes Pigmented Schwalbe’s line – AKA Sampaolesi’s line TM Gray CB What would you record? A. Schwalbe’s line – 1+ pigment B. TM – 1+ pigment C. Scleral spur – 1+ pigment D. CB band – 1+ pigment Sampaolesi's Line, pig glaucoma pt. Iris processes Gray CB What would you record? A. Schwalbe’s line B. TM C. Scleral spur D. CB band Gray CB Open angle with blood in Schlemm's canal What would you record? A. Schwalbe’s line B. TM C. Scleral spur D. CB band A hint of CB Lightly pigmented TM Lightly pigmented Schwalbe’s line Normal iris vessels www.gonioscopy.org.