Systems for Anterior Chamber Angle Evaluation 長庚紀念醫院青光眼科吳秀琛

Transcription

1 Systems for Anterior Chamber Angle Evaluation 長庚紀念醫院青光眼科吳秀琛

2 Clinical Techniques for Assessing Angle Width A light from the side showing physiological iris bombe

3 Slit lamp-grading of peripheral AC depth : The Van Herick Method

4 Principle of gonioscopy Overcoming total internal reflection gonioscopic lens: index of refraction similar to the cornea Indirect gonioscopy Direct gonioscopy. Reproduced with permission from the European Glaucoma Society (EGS). Terminology and Guidelines for Glaucoma. EGS, 2003 (2 nd Edn).

5 Purpose of gonioscopy Why do I need to perform gonioscopy? Fundamental part of comprehensive exam Most important factor in correct diagnosis Omission of gonioscopy is a common cause of misdiagnosis Done initially for all glaucoma patients and suspects Repeated periodically for patients with angle- closure glaucoma

6 Method of gonioscopy Direct gonioscopy Indirect gonioscopy Without indentation With indentation Without indentation With indentation: synechiae present Jain S

7 Koeppe lens Direct gonioscopy

8 Indirect gonioscopy Goldmann three-mirror lens 73 o 67 o 59 o

9 Indirect gonioscopy Slit lamp technique

10 Indirect gonioscopy Slit lamp technique Goldmann three-mirror lens

11 Indirect gonioscopy Posner four-mirror lens Four mirrors inclined at 64 o

12 Indirect gonioscopy Sussman four-mirror lens

13 Indirect gonioscopy Slit lamp technique Four-mirror lens

14 Indirect gonioscopy Slit lamp technique Insertion of lens

15 Normal angle structures Non-pigmented trabecular meshwork Pigmented trabecular meshwork Schwalbe s line Scleral spur Ciliary body band

16 Angle structures : iris Myopes concave Hyperopes convex Abnormal convexity (pupillary block) Abnormal concavity (pigment dispersion syndrome) Crypts (Fuchs ) Abnormal last roll (plateau iris)

17 Angle Structures : Ciliary Body Band Iris inserts into concave face Wide in: angle recession (scan circumference) cyclodialysis (cleft) Angle recession

18 Angle Structures : Scleral Spur Posterior border of TM Attachment of ciliary body Insertion of longitudinal muscles of ciliary body May be obscured by: iris processes iris bombé peripheral anterior synechiae pigments

19 Angle Structures: Trabecular Meshwork More pigmented with age Flow is through posterior TM Pigment is intracellular More pigment inferiorly ID by Schwalbe s line ID by blood in Schlemm s canal Anterior trabecular meshwork Posterior trabecular meshwork

20 Angle Structures : Schwalbe s Line Termination of Descemet s membrane Pigmented Sampaolesi s line Landmark for identification of TM in narrow angles

21 Angle Blood Vessels Normal vessels Radial orientation Thick Non-branching Do not cross the scleral spur Neovascularisation Fine Arborising Crosses scleral spur

22 Differentiating between Iris Processes and Synechiae Iris processes Fine Extend into scleral spur Follow concavity of recess Underlying structures seen Iris moves with indentation Broken with angle recession Synechiae Broad Extend beyond scleral spur Bridge concavity of recess Obscure structures Resist movement Intact

23 Recognition of sites of blockage in angle closure Pupillary block Plateau iris

24 Indentation Gonioscopy

25 Reproduced with permission EGS 2003 EGS 2003 Appositional closure Open angle Synechial closure

26 Indentation gonioscopy: synechial closure Reproduced with permission EGS 2003 EGS 2003 Synechial closure

27 Over-the-hill gonioscopy patient looks in the direction of the mirror

28 Plateau Iris Configuration

29 Indentation gonioscopy: plateau iris configuration Curvature of iris along anteriorly placed ciliary processes Dipping of the iris at lens equator Curvature of iris along lens surface S-curve configuration of iris

30 Drawings reproduced with permission from the EGS. Grading of angle width: Spaeth classification Insertion of iris root 1 EGS 2003 Angular width of angle recess A: Anterior to Schwalbe s line B: Behind Schwalbe s s line C: On the scleral spur D: Behind the scleral spur E: On the ciliary band Leuenberger EU Asian Eye Institute Slit 2 10º 20º } Narrow EGS º 40º } Wide Nolan W

31 The Spaeth classification Configuration of the peripheral iris 3 EGS 2003 s: steep, anteriorly convex r: regular q: queer, anteriorly concave Nolan W Trabecular meshwork pigment 4 0: none 4+: maximal Drawing reproduced with permission from the EGS.

32 Grading of angle width: Shaffer and modified Shaffer system Grade 0 Grade I Grade II Grade III Grade IV Shaffer Closed 10º 20º 30º 40º Modified Shaffer Schwalbe s line not visible Schwalbe s line visible Anterior TM visible Scleral spur visible Ciliary band visible Red = higher risk Yellow = medium risk White = lower risk SEAGIG. Asia Pacific Glaucoma Guidelines

33 Developmental Abnormalities Congenital glaucoma

34 Process of Exposing the Trabecular Meshwork during the Anterior Chamber Development A. If the angle developed by cleavage or atrophy of tissue, the ciliary muscle would be extended into the iris, and the ciliary processes would be in back of the iris B. According to Anderson, the angle develops secondary to a differential growth rate of the angle tissue. The ciliary muscle and ciliary processes, which are initially located over the TM, end up posterior to it.

35 Gonioscopy OD Gonioscopy OS

36 Developmental Abnormalities Posterior embryotoxon Image copyright 2003 Digital Reference of Ophthalmology ( Reproduced with permission.

37 Developmental Abnormalities Axenfeld s s anomaly

38 Summary Gonioscopy Fundamental part of ophthalmic evaluation Confirmation of normal angle structures Determination of narrowness or closure of anterior chamber angle Grading of angle width Pathological findings Needs to be performed routinely