Glaucoma

Glaucoma presentation for ophthalmology course, presented as a student seminar. Class location: ophthalmology unit, An-Najah National University Hospital.

1. Hasan Arafat Glaucoma الزَّرق، الماء الأزرق أو الماء الأسود

2. Introduction Glaucomas are a group of disease; All of these diseases cause damage to the optic nerve head; Axon loss results in visual field defects and decreased visual acuity.

3. Anatomy & Physiology IOP is determined by a balance between production and removal of aqueous humor Aqueous is actively secreted into the posterior chamber by the ciliary processes It then passes through the pupil into the anterior chamber and leaves the eye Aqueous drains through two pathways

4. Glaucoma and Blindness Glaucoma is the second most common cause of blindness, two theories exist: Raised intraocular pressure causes mechanical damage to the axons Raised intraocular pressure causes ischemia of the nerve axons by reducing blood flow at the nerve head

5. Classification: Primary Glaucoma The mechanism by which aqueous drainage is reduced provides a means to classify the glaucoma: clear of the trabecular meshwork ( open angle glaucoma ); covering the meshwork ( closed angle glaucoma).

6. Open-Angle Glaucoma The trabecular meshwork is normal structurally Functionally, the meshwork shows increased resistance to aqueous outflow Causes: Thickening in the trabecular lamellae (reduced pore size); reduction in the number of lining trabecular cells; increased extracellular material in the trabecular meshwork spaces . Normal tension/low tension glaucoma O cular hypertension

7. Open Angle Glaucoma History Symptoms depend on the rate in which IOP rises Usually symptomless The patient might present after they notice a visual deficit Usually discovered by chance by an optometrist Examination White eye, clear cornea Measure the IOP using a tonometer Measure the corneal thickness using a pachymeter Examine the iridocorneal canal using a gonioscopy Examine the optic disc and identify pathologic cupping Exclude secondary causes

8. Goldman Tonometer Pachymeter

9. Gonioscope

10. Open-Angle Glaucoma Medical Treatment Topical Agents β -blockers Parasympathomimetics Sympathomimetic α -2 agonists Carbonic Anhydrase Inhibitors Prostaglandin Analogues Systemic Agents Carbonic Anhydrase Inhibitors Surgical Treatment Trabeculectomy Laser Trabeculoplasty

11. Open-Angle Glaucoma Trabeculectomy Procedure Trabeculectomy Bleb

12. Closed-Angle Glaucoma Occurs in small eyes ( hypermetropes /Asians) due to their shallow anterior chamber Increased resistance to aqueous flow increases the pressure in the posterior chamber Pressure pushes the iris forward, obstructing aqueous outflow Long standing contact between the iris and the drainage angle leads to peripheral anterior synechiae

13. Closed-Angle Glaucoma Impaired drainage increases IOP Increased pressure deprives the entire cornea of nutrition and the posterior cornea from oxygen This leads to clouding of the cornea and pressure on the optic nerve, leading to decreased vision Usually preceded by subacute attacks, in which the patient experiences increased IOP, headache and colored halos around light

14. Closed-angle glaucoma affects Asians because of their naturally small eyes

15. Closed-Angle Glaucoma History Photophobic, very painful eye Watering of the eye Loss of vision N/V, referred abdominal pain Examination Visual acuity is reduced Red eye Cloudy cornea Oval, dilated, fixed pupil

16. Closed-Angle Glaucoma Treatment C ombined medical and surgical, must be urgent Acetazolmide (IV & oral) Topical pilocarpine and β -blockers Iridotomy / iridectomy +/- a procedure to relieve PAS

17. Secondary Glaucoma Caused by obstruction of the trabecular meshwork Meshwork abnormalities Hyphema Uveitis Pigment dispersion syndrome Pseudoexfoliative glaucoma Steroid-induced glaucoma Angle abnormalities Angle recession (trauma) Uveitis Large choroidal melanoma Cataract Rubeosis iridis

18. Secondary Glaucoma Treatment Depends on the primary cause In refractory cases, ablation of the ciliary processes might be required, this is performed using laser or cryoprobe to the sclera overlying the area of choice

19. Congenital Glaucoma The cause of congenital glaucoma remains uncertain One view is that the iridocorneal angle is developmentally abnormal and covered with a membrane which increases the outflow resistance

20. Congenital Glaucoma S/ Sx excessive tearing, photophobia and blepharospasm ; an increased corneal diameter and enlargement of the globe ( buphthalmos ), resulting in progressive myopia; a cloudy cornea due to epithelial and stromal edema; splits in Descemet’s membrane .

21. Congenital Glaucoma Treatment Surgical treatment Goniotomy Trabeculotomy

22. A child with congenital glaucoma

23. Prognosis of Glaucoma