Glaucoma for undergraduates

Aquaus humour formation&drainage
Angle structure
IOP measurement
POAG

1. By/ Mohamed Ahmed El – Shafie Assistant Lecturer in ophthalmology department KafrELShiekh University

2. 4 What is glaucoma? • Disease of the optic nerve. • When damage to the optic nerve fibers occurs, blind spots develop; blind spots usually go undetected until optic nerve is significantly damaged. Normal vision Vision as it might be affected by glaucoma

3. Anatomy of the drainage angle The anterior chamber(AC) is that space, containing aqueous humor, which is bounded in front by the cornea and part of the sclera, and behind by the iris and part of the ciliary body. Its normal depth in adults varies from 2.5-3.5mm. The angle of the anterior chamber. refers to that peripheral recess bounded posteriorly by the root of the iris and the ciliary body and anteriorly by the corneo-scleral junction or the limbus. there is an annular channel, called the canal of Schlemm. The canal is separated from the aqueous in the anterior chamber by the trabecular meshwork.

4. Anatomy of glaucoma • Clear liquid called aqueous humor circulates inside the front portion of the eye. • To maintain a healthy level of pressure within the eye, a small amount of aqueous humor is produced constantly, while an equal amount flows out of the eye through a microscopic drainage system—the trabecular meshwork .

5. Anatomy of glaucoma • With glaucoma, aqueous humor does not flow through the trabecular meshwork properly. • Over time, eye pressure IOP increases, damaging the optic nerve fibers.

6. Types of glaucoma Two main categories of glaucoma: • Open-angle glaucoma : the most common form of glaucoma - (the most common form that affects approximately 95% of individuals) • Closed-angle glaucoma : a less common and more urgent form of glaucoma. Other Types of glaucoma: Normal-Tension Glaucoma Congenital glaucoma Juvenile glaucoma Secondary glaucoma

7. Classification of glaucoma . 1-Angle configuration a- open(POAG=primary open angle glaucoma). b-Narrow/closed.(PACG=primary angle closure) 2-Onset a-acute(acute congestive glaucoma)red eye differential diagnosis. b- Chronic(primary open angle glaucoma) 3-Causes a-primary(POAG/PACG) or congenital/ developmental glaucoma. c-acquired/ secondary glaucoma(secondary open angle and secondary close angle…) Secondary to other ocular diseases. neovascular glaucoma in CRVO or in diabetic eye disease lens induced in neglected cataract.

8. Types of glaucoma – Open-angle Open-angle glaucoma • Trabecular meshwork becomes less efficient at draining aqueous humor. • Intraocular pressure (IOP) builds up, which leads to damage of the optic nerve. • Damage to the optic nerve occurs at different eye pressures among different patients. Open-angle glaucoma

9. Glaucoma risk factors – Open-angle Strong risk factors for open-angle glaucoma include: High eye pressure (IOP) Family history of glaucoma Age 40 and older Thin cornea Suspicious optic nerve appearance with increased cupping (size of cup, the space at the center of optic nerve, is larger than normal) High myopia (severe nearsightedness) Diabetes Eye surgery or injury Use of corticosteroids (for example, eye drops, pills*, inhalers and creams)

10. Examination of the visual field

11. IOP depends on the relationship between aqueous production and outflow. The normal ocular tension is between 10-21mm.Hg. There is a normal fluctuation in ocular tension of up to 3-5mm.Hg. during the course of the day called diurnal variation.

12. Digital palpation of ocular tension

13. Detecting Glaucoma Tonometry: The tonometry eye test measures the inner pressure of the eye also known as Intraocular Pressure or IOP. Indentation Tonometry: Schiotz tonometer

14. Types of Tonometry: Applanation tonometry measures intraocular pressure either by the force required to flatten a constant area of the cornea (e.g. Goldmann tonometry) or by the area flattened by a constant force.

15. Types of tonometry non-contact tonometry or air-puff tonometry: This type of tonometer uses a rapid air pulse to applanate the cornea. Intraocular pressure is estimated by detecting the force of the air jet at the instance of applanation . In most cases a stationary unit, Does not require anesthetic drops

16. Types of tonometry Tono -pen - is a portable electronic, digital pen-like instrument that determines IOP by making contact with the cornea, after use of topical anesthetic eye drops – tip covers are used between the patients.

17. Types of tonometry The newest Advancement in tonometry is DIATON TONOMETER – It measures intraocular pressure (IOP) through the Eyelid. Diaton Tonometer is intended for use by Inpatient & Outpatient Clinics such as Hospitals, Emergency Rooms, Nursing & Elderly Homes, General & Specialty Practitioners as well as Ophthalmologists and Optometrists. DIATON Requires No Contact with Cornea No Anesthetic Drops, No Risk of Infecting

18. Diaton Tonometry Safe Quick Efficient Painless Noninvasive Can be used on Children and Adults

19. Disc: damage usually begins as an upper or lower temporal notch, giving rise to a nasal arcuate scotoma, then progressive cupping can occur with progressive field loss FUNDOSCOPY

20. E xamination technique used to visualize the structures of the anterior chamber angle. Mastering the various techniques of Gonioscopy is crucial in the evaluation of the Pathophysiology of aqueous humor outflow obstruction and the diagnosis of the various glaucomas . GONIOSCOPY.