Chronicity. Narrow Minded. Course Outline. Acute angle closure. Subacute angle closure. Classification of Angle Closure 5/19/2014

Transcription

1 Chronicity Narrow Minded The management of narrow angles in the optometric practice Acute Subacute Chronic Aaron McNulty, OD, FAAO Course Outline Classification of Angle Closure Evaluation of narrow angles Treatment options for narrow angles Acute angle closure Pain Conjunctival hyperemia Hazy cornea Mid-dilated pupil Glare Nausea Only 20-30% of angle closure cases Classification of Angle Closure Based on chronicity Acute Subacute Chronic Based on glaucomatous damage Based on etiology Pupillary block Other Subacute angle closure Self-resolving or aborted acute episode Recurrent subacute episodes= intermittent angle closure May cause peripheral anterior synechiae and creeping angle closure 1

2 Chronic angle closure Peripheral anterior synechiae (PAS) Permanently closed angle Elevated IOP Usually asymptomatic Primary angle closure Evidence of previous or current angle closure Elevated IOP, anterior synechiae No glaucomatous damage Glaucomatous Damage Primary angle closure suspect Primary angle closure Primary angle closure glaucoma Primary angle closure glaucoma Glaucomatous nerve damage and/or visual field loss consistent with glaucoma Primary angle closure suspect Very commonly encountered No elevated IOP No anterior synechiae No glaucomatous damage No visual field loss Iridotrabecular contact is present or considered to be possible Primary angle closure progression How many suspects progress to angle closure? Wilensky et. al: Occludable angles, median 3 years of follow up 6% acute angle closure 13% small areas of appositional or synechial closure Alsbirk: van Herick 2 or less, shallow anterior chamber. Followed for 10 years 3% acute angle closure 13% chronic angle closure 2

3 Etiology Pupillary block (primary angle closure) Non-pupillary block Plauteau iris Phacomorphic Neovascular Malignant glaucoma Drug induced Pupillary block May result from pupil dilation Pharmacologic or physiologic Most likely at mid-dilated state as pupil recovers from dilation Peripheral iris laxity caused by dilation iris bombe Pupillary block AKA primary angle closure Most common mechanism Iridolenticular contact disrupts flow of aqueous Accumulates in posterior chamber Iris bombe Angle closure Plateau iris Phacomorphic Non-pupillary block Neovascular Malignant glaucoma Drug induced Angle crowding caused by thick peripheral iris rolls During maximal dilation Pupillary block Relative pupillary block No iridolenticular contact Relative resistance to aqueous flow Aqueous pressure is higher behind the iris (and at optic nerve) One to eight mmhg Equalized by iridotomy Evaluation & Management of narrow angle glaucoma Acute angle closure Chronic angle closure Primary angle closure suspect 3

4 Acute angle closure Rare; ophthalmic emergency Compression gonioscopy Differentiate between appositional and synechial closure Primary angle closure suspect Assess angle closure risk Various methods van Herick Gonioscopy Provocative testing Anterior segment OCT Ultrasound biomicroscopy Acute angle closure Pupillary block treatment Beta-blockers Alpha-agonists Pilocarpine Acetazolamide Supine position? Laser iridotomy van Herick Occludable angle: Anterior chamber depth less than one fourth of corneal thickness Chronic angle closure Decrease IOP Topical and/or oral medications Peripheral iridotomy? Address cause of angle closure i.e. neovascularization Long-term hypotensive drops may be needed Prostaglandins may work even in cases of 360 degree PAS Gonioscopy More detailed than van Herick Subjective and more difficult Perform in dim light to avoid pupil constriction and falsely open angles Occludable angle: failure to view the posterior trabecular meshwork in at least 180 degrees Varying opinions; no clear consensus 4

5 Provocative Testing Darkroom prone test Pharmacologic pupil dilation Not commonly used Not readily reversible Low sensitivity and specificity Hypotensive drops Iridotomy Iridoplasty Plateau Iris Treatment Overview Anterior Segment OCT Easy to perform; noninvasive May be performed in dark No visualization of synechiae, pigment, or neovascularization Drops Acute Angle closure kit Chronic Prostaglandins May be effective even if TM is completely occluded Consider iridotomy if angle opening is less than 5-10 degrees Ultrasound Biomicroscopy Allows deep visualization into posterior chamber Resolution not as high as OCT More invasive than OCT Iridotomy Relieves resistance in the iris-lens channel Provides alternate route for aqueous flow Iris flattens, angle widens When to recommend for prophylaxis? Various approaches; no consensus My threshold? Failure to visualize PTM in at least 180 degrees Goal: prevent acute and chronic ACG 5

6 Iridotomy Efficacy As many as 30% of eyes retain narrow angles following iridotomy Very few of these go on to have attacks of increased IOP Risks/complications Uveitis, IOP spike, hyphema, synechia formation, monocular diplopia/glare Faster development of cataract? Iridoplasty Plateau iris Steep iris approach at its insertion, central flattening Absence of clinical trials showing benefit Thank you! Questions? 6