6/12/2019

Anterior Chamber Angle: Introduction Assessment and Anomalies  Native Oregonian and Willamette Bearcat

 UC Berkeley School of Optometry 2008

 San Francisco VA Residency 2009

 VA Staff Optometrist – teaching

Dave Hicks, OD, FAAO  Regular lecturer at AAO and other meetings

GWCO  No conflicts of interest Portland, OR October 10, 2019

Goals

 Review anatomy of the anterior chamber angle

 Review gonioscopy and other imaging techniques for evaluating the angle and anterior chamber

 Discuss abnormal angle and anterior chamber findings and management

www.gettyimages.com

Angle Anatomy Overview

 Iris

 Ciliary body (CB)

 Scleral spur (SS)

 Trabecular meshwork (TM)  Pigmented and non-pigmented

 Schwalbe’s Line (SL)  Sampaolesi’s line when pigmented www.oculist.net

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Angle Anatomy Overview

SL  Iris processes TM  Fine extensions toward TM or SL  Usually still allow a view of the angle SS  Differentiate from peripheral ant. synechiae (PAS)

CB  Greater circle of iris (MAC)  Anterior ciliary and long posterior ciliary arteries Iris

 Both normal, but could mimic NV

http://projects.mtmercy.edu/library/Tillage2/allen15.jpg

Iris Processes

 Usually end at SS, but can go to SL

Ferreras. Glaucoma Imaging, 2012. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009. www.oculist.net from Wolff E: Anatomy of the Eye and Orbit, 4th ed. Blakiston-McGraw, 1954.

Angle Vessels Angle Neovascularization (NVA)

 Differentiate from normal iris vessels

 Causes – DM, CRVO, OIS, tumor, etc.

 Significance

 Evaluation – gonio

 Management – depends on etiology http://dro.hs.columbia.edu/circvessels.htm http://glaucomaassociates.com/glaucoma/types-of-glaucoma/#Neovascular Glaucoma

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Angle Function Van Herick Estimation (1969)

 Maintain IOP Angle Limbal AC Depth Grade vs. Corneal Thickness  Aqueous outflow pathways 0 Slit  Conventional: TM → Schlemm’s canal → intrascleral channels → episcleral veins 1 <1/4 2 1/4  Unconventional (uveoscleral): ciliary muscle fiber spaces → supraciliary and suprachoroidal space 3 1/4 to 1/2 → scleral emissary canals 4 1 or more

Gupta D. Glaucoma diagnosis and management, 2005. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Gonioscopy Angle Grading Systems

 Gold standard  Sheie: no longer used  Technique  Lighting: dark room, smallest  Shaffer: grades 0-4, widest is 4 possible beam height/width  Try to avoid miosis  Modified Shaffer: angle structures named  Innate variability, prone to error  Spaeth  Indentation gonioscopy  Appositional vs. synechial closure

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Shaffer System Spaeth System

 Grade 4 = CB  Step 1: Site of iris insertion  A = Anterior to TM (i.e. SL)

 Grade 3 = SS  B = Behind SL (i.e. at TM)  C = Centered at SS  D = Deep to SS (i.e. anterior CB)  Grade 2 = TM  E = Extremely deep in CB

 Grade 1 = SL  Step 2: Angle width  10 degree increments  Grade 0 = No structures (NS)

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

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Spaeth System Spaeth System

 Step 3: Configuration of peripheral iris  Original  New  s = steep/convex  b = bows 1 to 4+  r = regular or flat  p = plateau  q = quixotic/queer  f = flat or deeply concave  c = concave  E40c, 4+TMP – very deep  Step 4: TM pigmentation  A10b – very narrow  Grade 1-4  D40f, 2+ TMP – normal

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Normal Open Angle

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Anomalous Angle Findings

 Common pigment  Age-related  Pigment dispersion syndrome  Pseudoexfoliation

 Concerning pigment  Uveal or ring melanoma

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Melanoma Features

 Unilateral  Pigmented aqueous cells  Iris displacement and heterochromia  Subluxed lens  Sectoral cataract  Shallow AC or closure  Choroidal: 69-90%  NVI  Iris/CB: 4-8%  Variable IOP, usually elevated  Dark angle pigment  Prominent episcleral vessels

Lee, et al. BJO, 1999; 83: 194-198. Warner and Pasquale. Sem in Ophthalmol, 2006; 21: 181-189. Warner and Pasquale. Sem in Ophthalmol, 2006; 21: 181-189.

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Anomalous Angle/AC Findings

 Deep angles  Iris to TM angle 20-45 degrees  PDS

 Angle recession  Can be sectoral or Melanoma circumferential  Trauma

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Angles At Risk

 Iris to TM angle <20 degrees TM  2-6% of Caucasians

SS  Irido-trabecular contact preferred term over “narrow” or “occludable”  1800 vs. 2700 CB Iris  ACA deemed closed if iris touches cornea anterior to SS

Photo: Dave Yang, OD, FAAO Hu, et al. J Glaucoma, 2016;25;177-183. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

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Primary Angle Closure (PAC) Primary Angle Closure (PAC)

 PAC suspect  PAC glaucoma (PACG)  >2700 of irido-trabecular contact  >2700 of irido-trabecular contact  Shaffer grade 2 or less  Elevated IOP  No PAS  Optic nerve and VF damage  Normal IOP, optic nerve, and VF

 PAC  >2700 of irido-trabecular contact  Either elevated IOP or PAS  Normal optic nerve and VF

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009. Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Closure impossible Closure possible

Closure probable Angle closed

Closed angle

Stamper, Lieberman, Drake. Diagnosis and Therapy of the Glaucomas, 2009.

Safe Dilation

 Shaffer grade 3 or 4

 Less than 1800 of irido-TM contact  High resolution ultrasound  Risk of angle closure with dilation  Non-invasive, two-dimensional  Rotterdam: ~1 in 3,380 (Caucasians)  Quantitative and qualitative  Others: ~1 in 20,000 with both trop/phenyl  Not as deep as B-scan  Minimal to no risk with just tropicamide  Takes training – eye cup, water bath

Pandit, Taylor. Diabetic Med, 2000; 17:693-699. Wolfs, et al. IOVS, 1997; 38:2683-2687. Dada, et al. Surv Ophthalmol, 2011 Sept-Oct; 56(5);433-450.

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AC

Angle

Deep

Closure

http://synemed.com/ultrasound.html www.accutome.com Dada, et al. Surv Ophthalmol, 2011 Sept-Oct; 56(5);433-450.

UBM terminology UBM of CB tumor

 ARA – angle recess area  TIA – trabecular iris angle  AOD 250/500 – angle opening distance  TCPD – trabecular-ciliary process distance  ICA – iridociliary angle PAS in same pt  ID1 to ID3 – iris thickness measurements  ICPD – iris-ciliary process distance  ILCD – iris-lens contact distance (a) Ultrasound biomicroscopy of a ciliary body tumor extending up to the pars plana. C: Cornea, S: Sclera, CB: Ciliary body. (b) Peripheral anterior synechiae on gonioscopy in the same patient  IZD – Iris zonular distance Dada, et al. Eye, 2007; 21;956-961. Masslin, et al. IJO, 2015 Aug; 63(8);630-640. Dada, et al. Surv Ophthalmol, 2011 Sept-Oct; 56(5);433-450.

UBM of LPI Plateau Iris

Posterior iris turns sharply to insertion  Widening of ACA in PAC, not in PACG (Dada) Iris inserts to anterior CB  28% of PACS convert to PAC after LPI (Ramani) Flat or concave iris, deep central AC H. Quigley Dada, et al. Eye, 2007; 21;956-961. Ramani, et al. J Glaucoma, 2009;18;521-527. He, et al. Ophthalmol, 2007;114 (8);1513-1519. Steiger, et al. Clin Exp Ophthalmol, 2007 Jul; 35(5):409-413.

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Plateau Iris UBM of ALPI

 Plateau Iris Configuration  Plateau Iris Syndrome – post LPI

 Compression gonio  “double hump” sign

 Treatments  LPI  ALPI  Cataract surgery

Steiger, et al. Clin Exp Ophthalmol, 2007 Jul; 35(5):409-413. Masslin, et al. IJO, 2015 Aug; 63(8);630-640.

Anterior Segment OCT

Hu, et al. J Glaucoma, 2016 Feb; 25(2);177-83. Angmo, et al. OJO, 2016 Jan-Apr; 9(1);3-10.

AS-OCT Basics AS-OCT Terminology  Time domain at 1310nm  Single scan of entire AC  SL-angle opening distance (SL-AOD)  Fourier domain at 830nm  AOD 500/750  Can see SS, SL, etc  SL-trabecular iris space area (SL-TISA)  ACV – Anterior chamber volume  Swept source at 1310nm  ACD – Anterior chamber depth  3D angle analysis  ACA – Anterior chamber area  ACW – Anterior chamber width  May identify more PAC than gonio  Iris thickness at 750um  LV – Lens vault

Radhakrishnan. Curr Opin Ophthalmol 2014, 25:98–103.

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PAC

Swept Source (HD)

PAS Need to identify angle structures

Time Domain

Radhakrishnan. Curr Opin Ophthalmol 2014, 25:98–103. Masslin, et al. IJO, 2015 Aug; 63(8);630-640.

APAC Appositional Angle Closure

Phacomorphic AC

Moghimi, et al. IOVS, Masslin, et al. IJO, 2015 Aug; 63(8);630-640. 2015;56;7611-7617.

AS-OCT vs. UBM

 Non-contact  Contact, coupling  1 eye of 50 pts  Minimal training  Skilled operator  60% women  Better resolution  Lower resolution  64% Caucasian  Faster  Slower  All phakic  Wider FOV  Shorter FOV  POAG, ACG, OHTN,  Upright  Supine or upright or PXG

 Limited ability to  Can visualize Visante and Cirrus OCT may have limited visualize structures posterior to iris ability to identify angle closure because of posterior to iris difficulty identifying angle structures

Masslin, et al. IJO, 2015 Aug; 63(8);630-640. Hu, et al. J Glaucoma, 2016;25;177-183.

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 Iris to TM angle <20 degrees  Still at risk

 Lack of visibility more superior and inferior

Hu, et al. J Glaucoma, 2016 Feb; 25(2);177-83.

Image: Zeiss

Anomalous Angle and AC Findings

 Iridodialysis

 Retained lens fragments after CE

 Literature review for PAC  Anterior chamber intraocular lenses  UBM, AS-OCT, Scheimpflug, SPAC

None of these imaging methods provides  Hyphema/microhyphema sufficient information about the ACA anatomy to be considered a substitute for gonioscopy

Smith, et al. Ophthalmol, 2013; 120: 1985-1997.

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Iridodialysis

 Traumatic, iatrogenic, or congenital

 Can be asymptomatic

 Glare, diplopia, photophobia

 IOP issues  TM damage, PAS, CB damage

 Need to rule out melanoma

SS

CB

Retained Lens Fragments

 Almost always in inferior angle  Can require gonio to visualize  Cortical vs. nuclear  16 eyes at Bascom Palmer, retrospective  Time to diagnosis is highly variable  Time to discovery: 1-182 days, average 38  Corneal edema, uveitis, IOP, glaucoma  37.5% of fragments were not visible by SLE  Cortical – resorption can occur  Treatment – corticosteroids, IOP  Nuclear – more corneal edema lowering meds, surgery  Both have AC reaction and need steroids  Surgical removal may be required

Hui, et al. Ophthalmol, 2006; Nov;113(11):1949-53.

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 54 eyes at Duke  Time to discovery: 1 day to 6+ months  87% of fragments were diagnosed by SLE  56% of eyes had corneal edema  Inferior edema should be a clue  Surgical removal recommended in all cases

Zavodni, et al. AJO, 2015 Dec;160(6):1171-1175.

ACIOLs Surgical PI

 Safety for dilation  Iris fixation  Surgical iridectomy vs laser iridotomy  Pupil clearance, lens capture Sutures

 Uveitis

Belkin et al. Cornea, 2015; 34(12): 1573-6.

Suture

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Murra, et al. AJO, 2010 Feb;149(2):245-252.

Photo: Eddie Chu, OD, FAAO

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Microhyphema

 Significance

 Causes – trauma, surgery, PXF

 Evaluation – photos, gonio, iris FA

 Management – depends on etiology

Conclusions

 The angle and anterior chamber are vital but often overlooked structures

 Knowledge of angle anatomy and various examination techniques are important to make proper diagnoses

 Management and timely referral when complications develop is crucial

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Thank you!

Questions? [email protected]

References available upon request

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