GLAUCOMA RESEARCH WORK AND PRESENTATIONS PPT

My research work on glaucoma

1. A SEMINAR PRESENTATION ON GLAUCOMA BY ADIZUA KENDRICK .C JULY, 2024

2. TABLE OF CONTENT INTRODUTION DEFINITION ETIOLOGY CLASSIFICATION RISK FACTORS DIAGNOSIS TREATMENT WHAT GLAUCOMA LOOKS LIKE

3. INTRODUCTION Glaucoma is a large group of progressive eye diseases characterized by damage to the optic nerve. Optic nerve damage that is caused by eye pressure is called glaucomatous damage. It is visible during an eye exam as a distinctive cupping out of the optic disc. Glaucoma occurs as a result of increased intraocular pressure (IOP) caused by a malformation or malfunction of the eyes drainage system. Normal IOP is 1 1-21mmHg . The increased pressure causes compression of the retina and the optic nerve, and causes progressive , permanent loss of eyesight if left untreated. DEFINITION Glaucoma is a group of disorder characterized by an abnormally high intraocular pressure , optic nerve dystrophy, and peripheral filed loss. BRUNNER

4. ETIOLOGY Increased intraocular pressure.( more than 24 mmhg) Optic nerve dystrophy.

5. Fig 1: diagram showing aqueous d drainage The aqueous humor is produced behind the iris, flows into the anterior chamber through the pupil, and exits the eye between the iris and cornea. Too much aqueous production or obstruction of its outflow causes a rise in IOP that can lead to glaucoma.

6. CLASSIFICATION GLAUCOMA 1 . True congenital 1. primary glaucoma 2.infantile 2. Secondary glaucoma 3. juvenile ACQUIRED CONGENITAL

7. CONGENTIAL GLUCOMA Rare disease. Occurs when a congenital defect in the angle of the anterior chamber obstructs the outflow of aqueous humor. If left untreated causes damage to optic nerve and blindness. True Congenital Glaucoma congenital glaucoma often have obvious signs of the condition at birth, such as abnormally large eyes or clouded corneas. This is because the built-up fluid and pressure has stretched and enlarged the eyes. But some babies born with (CG) have later onsets of these signs that range from a few weeks up to around two years. INFANTILE GLAUCOMA occurs three days after birth occurs about 10% of cases.

8. JUVENILE GLAUCOM A It is also congenital, but its onset tends to be later in early childhood ie occurs during 3 to 16 years of life. Children diagnosed with JOAG are less likely to have enlarged eyes due to this later onset. Clinical features of congenital glaucoma 1. Lacrimation 2. Photophobia 3. Corneal oedema 4. Raised IOP 5. Eyes Become MYOPIC 6. Corneal diameter more than 13mmhg

9. AQUIRED GLAUCOMA 1. Primary Glaucoma: They are called primary because they develop on their own, without any known cause. Most cases fall into this category. a. Primary open-angle glaucoma (POAG) When glaucoma develops even though there are no visible obstructions in the angle, it’s called open-angle glaucoma. In most cases, this form is due to resistance in the TM on a microscopic level. This form usually develops due to structural changes in the trabecular meshwork (TM) or, less often, in Schlemm’s canal. It’s called open-anglebecause nothing is blocking or restricting the eye’s drainage angle.Instead, the tissues of the TM become stiff, or the number of its sponge-like pores decreases. These changes make it difficult for aqueous humor to pass through, and then IOP goes up. If POAG is detected early, it’s possible for many patients to avoid significant vision loss. But POAG rarely has symptoms, and it progresses very slowly. An estimated 50% of people never realize they have it until they experience significant loss of vision. The only way to catch it early is to have yearly comprehensive eye exams. 

10. Fig 2:Primary open-angle glaucoma

11. b. Primary angle-closure glaucoma (PACG) : When glaucoma develops because the angle is obstructed, it’s called narrow-angle or angle-closure glaucoma. In this form, the angle is blocked or partially blocked by the outer edge of the iris. It develops when the outer edge of the iris shifts and blocks the drainage angle. Though it gets its name from this blockage, it usually results from a problem earlier in the aqueous outflow path. The underlying cause of narrow angles is usually pressure behind the iris that causes the iris to bow forward. When the iris is bowed, its outer edge is pushed forward and toward the angle. And its inner edge, which forms the pupil, is pulled backward toward the lens. ACG is usually chronic, meaning it progresses slowly, but it can also be acute. The chronic form is the second-most common after POAG and rarely has symptoms.  The acute (sudden) form is much less common, but it does have symptoms and is very serious. An acute attack can cause intense eye pain, blurry vision, and nausea or vomiting. Untreated acute angle-closure glaucoma causes blindness within hours or days. It is a medical emergency that needs to be treated immediately.

12. Fig3: Angle- closure glaucoma(PACG)

13. d. Low-tension or normal-tension glaucoma (NTG) When optic nerve damage develops in eyes that have open angles and typical IOP, it is called normal-tension glaucoma. It is often categorized as a type of POAG.  Either way, normal-tension glaucoma is extremely common. Some people may develop NTG because their optic nerves have poor blood flow or are more structurally vulnerable to pressure. Another theory is that their eyes are less able to withstand normal pressure due to size, shape, wall thickness or corneal thickness.  It may also be due to an autoimmune issue or to higher sensitivity to typical, daily IOP fluctuations. 

14. 2. Secondary glaucoma The optic nerve damage that occurs with a secondary glaucoma is the same as in a primary form. The difference between the two is that secondary glaucoma has causes that are distinct and identifiable. Secondary glaucoma can be caused by underlying health conditions, eye disease and eye injuries. It can also be caused by medication side effects or eye surgery. It can be open-angle or angle-closure, and its different causes can lead to multiple types of glaucoma.  Some of the more common types include: 

15. a. Neovascular glaucoma (NVG) – NVG is often a result of diabetic retinopathy or other causes of poor blood circulation of the eye. It develops when reduced blood flow to the retina triggers an overgrowth of abnormal blood vessels on the iris that eventually clogs the angle.  b. Exfoliative & pigmentary glaucoma – These are separate but similar forms caused by exfoliation syndrome (ES) and pigment dispersion syndrome (PDS). Accumulation of abnormal cellular dandruff (with ES) or flakes of iris pigment (with PDS) in the angle lead to high IOP and glaucoma.  c. Topiramate is a medication that treats migraines, seizures and neuropathic pain. In some people, it can cause secondary angle closure. Topiramate glaucoma tends to affect both eyes, unlike PACG, which usually only occurs in one eye. Eye pressure usually rises in both eyes within the first weeks of taking topiramate. 

16. c. Steroid-induced glaucoma – This type develops when steroid use (prescribed and OTC) causes both structural changes and increased debris deposits in the TM. Drainage resistance in the TM increases IOP and leads to glaucoma. People at increased risk of steroid-induced glaucoma include those who:  1. Have glaucoma already 2. family history of glaucoma 3. Type 1 diabetes 4. high myopia d. Uveitic glaucoma  This form develops secondarily to uveitis, which is inflammation of the uvea. Depending on which structures are affected, uveitic glaucoma can be open- or closed-angle, and it can be chronic or acute. It is considered one of the most challenging forms to treat. If someone has symptoms of uveitis, they should see an eye doctor right away. 

17. e. Traumatic glaucoma   When an eye suffers any type of injury or trauma, the inflammation and/or damage to its tissues and internal structures will often lead to elevated IOP. An estimated 3% to 10% of people who experience eye trauma eventually develop traumatic glaucoma.  The injuries are most often associated with sports, assault, falls and jobsite accidents. However, in rare cases, this form can also develop after intraocular surgery, such as cataract surgery. This is due to an autoimmune reaction that some patients experience after the surgery. Traumatic glaucoma can be early onset or late onset. In many cases, it can take months and even years before the damage inside the eye leads to glaucoma. Angle-recession glaucoma is a late-onset form caused by injury. A blow to the eye can displace the aqueous fluid with enough force to push the drainage angle backward. The force can also tear tissues in the trabecular meshwork and ciliary body. Over time, these tears form scars that slow down outflow and raise IOP.

18. Risk factors Most forms of glaucoma have very similar risk factors, though there are a few differences. The biggest risk factor for all types of glaucoma is high intraocular pressure. The risk factors that overlap for nearly all types of glaucoma include:  i) high IOP ii) over age 40 iii) high blood pressure or heart disease iv) diabetes v) family history of any type of glaucoma vi) thin corneal tissue 

19. Some risk factors are mainly associated with certain types of glaucoma. There are a few overlaps with these, as well: Increased risk for POAG:   a. Black or Latin-American ancestry b. myopia (nearsightedness) Increased risk for PACG:   a. hyperopia (farsightedness) b. Being assigned female at birth

20. Increased risk for NTG:   a. larger optic discs b. Asian or Latin-American ancestry c. low blood pressure d. Raynaud phenomenon e. sleep apnea Increased risk for secondary glaucoma:  a. diabetes b. Using steroids c. previous eye injury or surgery d. Having previous eye conditions, such as uveitis, infections and retinal detachment

21. How is glaucoma diagnosed? Glaucoma can only be diagnosed through a series of tests performed by an ophthalmologist or optometrist.   Like with any kind of medical testing, they will ask you questions about your health history first. Then, depending on the order they perform the tests, they may dilate your pupils or numb your eyes with eye drops.  Pupil dilation is required for some of the tests, but numbing drops are not always necessary. Glaucoma tests are non-invasive and painless. However, the numbing drops can make it easier for you to avoid blinking when the doctor touches your eyes. 

22. 1)Perimetry test – to check if the visual field has been affected. Vision loss in glaucoma typically begins with peripheral vision. This test will check your peripheral vision, but it can also determine if central vision is affected.  Two types of perimetry: screening perimetry is a test used to detect whether peripheral vision is normal or abnormal. During threshold perimetry , the machine shows lights of different intensities. Threshold perimetry measures the degree of peripheral field loss. 2)Tonometry test – This test is used to measure your intraocular pressure (IOP). 3)Pachymetry test – This test measures the thickness of the cornea, which is important in screening for glaucoma. Thinner corneal tissue is a known risk factor for developing glaucoma also the thickness or thinness of corneal tissue can impact how accurate the IOP measurement is.

23. 4)Gonioscopy – An instrument used viewing the drainage angle. this procedure is done using goniolens. magnification of the slit lamp in combination with the goniolens to see if the angle is open or closed. The angle is examined for blockage such as scarring, angle recession and plateau iris. They will also check for clogging, such as pigment, pseudoexfoliation debris and new blood vessels (neovascularization). 5)Fundoscopy – A fundoscopic exam is a dilated eye exam that checks the background of retina and the optic nerve. This part of the test is critical in determining whether the optic nerve and retinal cells have been damaged.

24. 6)Optic nerve monitoring – As part of the eye exam, the eye doctor may also take some scans or images of the optic nerve. Optic nerve imaging can be extremely useful in monitoring for any issues.  OCT imaging is an accurate way to evaluate the thickness of different layers of the retina. The two most important layers to monitor for glaucoma are the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCC).  Checking the RNFL for thinning in an area close to the optic nerve is a very sensitive way to detect early glaucoma. Images of the GCC, which is the macula, can be compared with images of the RNFL as a very accurate way to monitor progression over time.

25. What glaucoma treatment options are available? While the treatments all aim to lower IOP, the specific treatments that are best for each patient will depend on the type of glaucoma they have and how advanced it is. Other factors that determine treatment options include prior eye surgeries and how much the IOP needs to be lowered.  There are three main categories of treatments: medications, laser procedures and surgery.  1. Medications – The first line of treatment is typically prescription eye drops. There are several types of eye drops to treat glaucoma, and they each work in different ways to reduce IOP.  Some increase the rate that aqueous humor can flow out of the eye, and others decrease the amount of aqueous humor made by the ciliary body. Some of them produce a combination of both effects.

26. i) Prostaglandin analogs work by increasing uveoscleral outflow. eg Latanoprost, travoprost and bimatoprost ii) Beta blockers, alpha adrenergic agonists and carbonic anhydrase inhibitors work by reducing the amount of aqueous humor the ciliary body produces. Beta blockers – Timolol and levobunolol iii) Alpha adrenergic agonists – Brimonidineand apraclonidine iv) Carbonic anhydrase inhibitors – Dorzolamide, acetazolamide and methazolamide v) Cholinergic agents work by increasing aqueous outflow through the trabecular meshwork. eg Pilocarpine

27. 2.Laser procedures  – Like the eye drops, laser surgeries lower IOP by improving drainage or by reducing aqueous humor production. They are usually the preferred alternative treatment if eye drops haven’t lowered IOP enough.  They can also be a good option for patients who experience side effects from their eye drops or who are unable to use them consistently.  A recent large study showed that laser procedures can be an effective first-line treatment. The effects of most laser procedures only last a few years, so they may need to be performed more than once.

28. Fig4: image showing laser Trabeculoplasty

29. 1. Trabeculoplasty – Laser trabeculoplasties are often used to treat POAG. They lower IOP by creating openings in clogged trabecular meshwork tissue. The most common forms are selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT). 2. Cyclophotocoagulation (CPC) – This procedure uses laser energy to shrink the tissues of the ciliary body and reduce its production of aqueous humor. 3. Laser peripheral iridotomy (LPI) –Iridotomies are primarily done to treat closed-angle glaucoma. They can also help to prevent angle-closure in patients who have narrow drainage angles. LPI improves aqueous outflow by creating a tiny hole in the iris so fluid can bypass the pupillary block. 

30. Fig5: image showing Laser Peripheral Iridotomy

31. 4. Scatter panretinal photocoagulation – For patients who have neovascular glaucoma, this treatment removes the stimulus that causes abnormal blood vessels to form. It also causes existing abnormal blood vessels to shrink and disappear. surgical procedure 3. Microsurgery (also called filtering or incisional surgery) – These procedures are usually the next step if eye drops and laser surgery haven’t worked to lower IOP enough. In different ways, they each improve IOP by surgically modifying how fluid leaves the eye.  They are more invasive than laser treatments and have longer recovery periods because they involve incisions. The benefits of microsurgery can last up to several years, but they aren’t permanent. Fortunately, it is possible to repeat most of them when necessary. 

32. Fig6: Image showing Trabeculectomy

33. 1.Trabeculectomy – This procedure creates a small flap, or filtering pocket, under the eyelid in the sclera. A tiny piece of the trabecular meshwork beneath the filter is also removed. Aqueous fluid can then bypass the clogged drainage structures and leave the eye through this path. The pocket also keeps fluid from draining too quickly. Fluid accumulates in the filter, forming a small bubble under the conjunctiva called a bleb.  2.Canaloplasty – This procedure works by dilating Schlemm’s canal (SC) with a microcatheter. The SC is the part of the drainage pathway that aqueous fluid flows into via the trabecular meshwork. 3. MIGS (minimally invasive glaucoma surgery) – MIGS procedures can be thought of as mini incisional microsurgeries. They are less invasive because the incisions are made in the cornea rather than in the sclera. There are several types of MIGS that lower IOP with various methods. Many of them involve placing very small stents or shunts inside the angle of the eye. They are good options for patients with early or mild glaucoma, but some of them can only be performed in combination with cataract surgery.

34. 4. Drainage implants – These small implants allow aqueous fluid to leave the eye through tubes or shunts. The base, or plate, of the implant is embedded between the conjunctiva and sclera to hold it in place. The tube or shunt extends from the plate into the anterior chamber. From there, the fluid flows back through the tube into the space between the sclera and the conjunctiva to be reabsorbed by the body. 5. Peripheral iridectomy – This procedure treats closed-angle glaucoma and involves the removal of a small portion of the edge of the iris. It works in the same way as an LPI to release pupillary block.   6. Biodegradable drug-delivery implant (Durysta)  – Durysta is not technically a surgery, though the implant is injected into the eye with a needle. Once in the eye, the tiny capsule rests in the drainage angle and releases a steady, constant dose of glaucoma medication for 90 days. After the capsule dissolves, the effects can last up to 24 months for some patients. However, the treatment can only be done once per eye.

35. What glaucoma looks like The images below show what people see during the beginning and progressing stages of glaucoma. They may help you recognize whether you have symptoms. However, you should not wait to have symptoms to seek treatment. fig7: image showing onset of glaucoma

36. 1. Loss of peripheral vision is almost never the first problem glaucoma patients notice. It’s common for their vision to blur slightly and for the patient to require more lighting than usual in order to see an object clearly. However, in most cases, glaucoma patients do not notice any early vision changes. Fig8: vision changes

37. 2. Individuals past the beginning stages of glaucoma may have trouble with clarity and differentiating color. It can be like looking through a pair of dirty glasses. They will also begin to experience peripheral vision loss, though they may not notice it. Fig9: peripheral visual field loss.

38. 3. With glaucoma, vision loss usually begins in a person's peripheral vision. Peripheral vision includes the outer edges around your whole visual field. In the early stages, this area of vision begins to fade.  Fig10: advanced stage

39. 4. As the glaucoma progresses, more and more peripheral vision is lost. However, the brain actually tends to ignore the faded areas of side vision for a long time. This is why most people are completely unaware of early vision loss. When we think of peripheral vision, we often imagine something like the previous two images. But peripheral vision also includes nasal peripherals (vision toward the nose) and upper and lower peripherals. These areas of vision can also be lost.

40. Fig11: end-stage glaucoma If left untreated, glaucoma will impact your entire field of vision, leaving very little, if any, sight. The vision loss is permanent and cannot be reversed or restored with treatment.

41. summary Glaucoma is the leading cause of irreversible blindness. Early detection and treatment are the most important steps to prevent vision loss. moreso 12th march of every year is designated as the world glaucoma day.

42. REFERENCE Johns Hopkins Medicine. accessed March 2023 Glaucoma. American Optometric Association . Accessed march 2023 Glaucoma FAQs Wills Eye Hospital. Wills Eye Hospital . Accessed March 2023. What is glaucoma? Glaucoma Research Foundation . accessed march 2023. Glaucoma: what every patient should know. wilmer Eye institute, johns Hopkins School of medicine. Accessed march 2023. https://www.allaboutvision.com/conditions/glaucoma