In The Name Of God

1. In The Name Of God

2. S.L.T Selective Laser Trabeculoplasty as Primary Treatment for Open-angle Glaucoma

3. Outline • Open-Angle Glaucoma • What’s open-angle glaucoma? • Diagnosing open-angle glaucoma • Treatments for open-angle glaucoma • What is SLT? • Preface • Historical Perspective • How Does it treat • Why SLT? • Benefits • Risks • SLT vs. ALT • How it’s Performed

4. What’s Open-Angle Glaucoma? • Fluid circulating inside eye • The eye receives its nourishment from a clear fluid that circulates inside the eye. • This fluid must be constantly returned to the blood stream through the eye's drainage canal, called the trabecular meshwork. • Excess fluid builds pressure • In the case of open-angle glaucoma, something has gone wrong with the drainage canal. • When the fluid cannot drain fast enough, pressure inside the eye begins to build. • Pressure pushes against the • optic nerve • This excess fluid pressure pushes against the delicate optic nerve that connects the eye to the brain. • If the pressure remains too high for too long, irreversible vision loss can occur.

5. Diagnosing Open-angle Glaucoma • Glaucoma is a “silent killer” or like “slow poison” In most cases it begins un-noticeably and damages the eyes without any sign or symptom till it is very late and the patient is almost at the verge of blindness. This is the reason that awareness about glaucoma and its treatment is important to prevent this blinding disease. Everyone should be checked for glaucoma at around age 35 and again at age 40. Those considered to be at higher risk, including those over the age of 60 should have their pressure checked every year or two. • Tonometer: • Your doctor will use tonometry to check your eye pressure. After applying numbing drops, the tonometer is gently pressed against the eye and its resistance is measured and recorded. • Ophthalmoscope • An ophthalmoscope can be used to examine the shape and color of your optic nerve. The ophthalmoscope magnifies and lights up the inside of the eye. If the optic nerve appears to be cupped or is not a healthy pink color, additional tests will be run. • Perimetry • Perimetry is a test that maps the field of vision. Looking straight ahead into a white, bowl-shaped area, you'll indicate when you're able to detect lights as they are brought into your field of vision. This map allows your doctor to see any pattern of visual changes caused by the early stages of glaucoma.

6. Treatments for Open-Angle Glaucoma To control glaucoma, your doctor will use one of three basic types of treatment: , , or . The goal of treatment is to lower the pressure in the eye. medicines laser surgery filtration surgery • Medicines • They work by either slowing the production of fluid within the eye or by improving the flow through the drainage meshwork. • Laser Surgery • Argon Laser Trabeculoplasty and Selective Laser Trabeculoplasty surgery treat the drainage canal. the laser beam is applied to the trabecular meshwork resulting in an improved rate of drainage. • ECP is another type of laser procedure. it treats the ciliary body. reduces the amount of fluid production thereby reducing the intra ocular pressure. • Filtration surgery • Filtration surgery is performed when medicines and/or laser surgery are unsuccessful in controlling eye pressure. During this microscopic procedure, a new drainage channel is created to allow fluid to drain from the eye.

7. Selective Laser Trabeculoplasty

8. Preface • Selective laser trabeculoplasty (SLT) is one of greatest advances in the surgical treatment of intraocular pressure (IOP) in patients with open-angle glaucoma. Prior to its introduction, medications and argon laser trabeculoplasty (ALT) were the ophthalmologist's primary tools.

9. Historical Perspective • ALT has been available for more than 20 years for treating patients whose open-angle glaucoma was not controlled by medication. • Results showed that ALT could be more effective than the topical agents available at the time. • However, ALT is not without complications: Studies have shown that the effect of ALT significantly diminished over time; • Furthermore ALT: • Damages the microstructure of the trabecular meshwork. • Produces heat which cause damage to the surrounding structural collagen fibers • Causes endothelial cells to migrate.

10. Historical Perspective • SLT may be an improvement over ALT; SLT Lowers Pressure With Minimal Damage • SLT was further developed by Coherent Medical (now Lumenis) with work done by Dr. Latina. In 1995 SLT was introduced worldwide, and it was cleared by the FDA in March 2001. • The key concept in the design of this laser system was to direct the energy towards only pigment-containing cells in the trabecular meshwork. • SLT requires a specially designed laser: • A short pulse to allow for thermal relaxation • Precise wavelength for optimal melanin absorption • Sufficient energy to heat melanin to the point that it releases cytokines • Sufficient spot size to ensure full coverage at the trabecular meshwork • Lumenis has specifically developed the “Selecta II Glaucoma Laser System” to these specifications, meeting all of the clinical conditions necessary to perform successful SLT procedures again and again.

11. Historical Perspective • Mark Latina, M.D. inventor of SLT did cell culture and animal experiments to determine the specific energy range for selective cell damage. • Through his investigation parameters were determined which would activate certain pigment containing meshwork cells while sparing immediately adjacent non-pigmented cells. • Further human studies showed the pressure lowering effects of Selective Laser Trabeculoplasty without observable damage to the trabecular meshwork cells.

12. How does SLT achieve lower pressure with minimal damage ? • The underlying mechanism is selective photothermalysis • Which enables the laser to precisely target intracellular melanin granules to activate individual cells while not disturbing adjacent non-pigmented cells. • The activated cells release cytokines that trigger a targeted macrophage response to the trabecular meshwork cells. • The macrophages reactivate the meshwork reducing fluid outflow resistance and lowering intraocular pressure. • SLT Uses Frequency Doubled, Q-Switched YAG Laser • For SLT the light energy is provided by a specially designed Q-switched, frequency doubled Nd:YAG laser operating at 532nm green with an output of from 0.3 to 1.5 mill joules. • The target tissue is melanin granules within individual trabecular meshwork cells. • Based on the size of the pigment granules, it is necessary to deliver the light energy within 1 microsecond. The Q switched laser pulse width is 3 nanoseconds, well within the required time interval to contain the energy and temperature rise to the pigment granules.

13. Experimental Results : Methods : • 45 eyes of 31 patients with open-angleglaucoma or ocular hypertension (intraocular pressure [IOP]23 mm Hg on 2 consecutive measurements) underwentselective laser trabeculoplasty as primary treatment. • All patientsunderwent complete ophthalmic evaluation before and at intervalsafter treatment. • This evaluation included • visual acuity • slit lampexamination • Ophthalmoscopy • Gonioscopy • visual field analysis. • The IOP was measured 1 hour, 1 day, 1 week, and 1, 3, 6, 12,15, and 18 months postoperatively. • During the follow-up period,patients were treated with topical antiglaucoma medicationsas required.

14. Experimental Results : Results : • Mean ± SD decreased by 7.7 ± 3.5mm Hg (30%), from 25.5 ± 2.5 mm Hg to 17.9 ± 2.8mm Hg (P<.001). • Only 2 eyes (4%) did not respond to selectivelaser trabeculoplasty, and 3 eyes (7%) required topical medicationsto control their IOP at the end of the follow-up period. • Fortyeyes (89%) had a decrease of 5 mm Hg or more. • Visual acuity,visual fields, and gonioscopic findings remained unchanged. • Complications included conjunctival redness and injection within1 day postoperatively in 30 eyes (67%). • One hour after selectivelaser trabeculoplasty, an increase in IOP of more than 5 mmHg was detected in 5 eyes (11%), while an increase in IOP between2 and 5 mm Hg was measured in 3 eyes (7%). Conclusion : • Selective laser trabeculoplasty is effectiveand safe as a primary treatment for patients with ocular hypertensionand open-angle glaucoma.

16. SLT; Benefits and Risks • Advantages: • safest glaucoma laser surgery available • effectively treats glaucoma and prevents future vision loss in the vast majority of patients • reduces or eliminates the need for glaucoma medication in many patients • extremely fast and precise treatment option • minimal or no discomfort experienced during the procedure • repeatable with minimal risk • SLT stimulates the body’s natural mechanisms to enhance outflow of the fluid in your eye. • Disadvantages: As with any surgery, complications can occur during SLT glaucoma laser surgery, but are not common. The most common side effect of SLT is: • an increase in intraocular pressure for a few hours following the treatment. Some possible complications include : • Irritation • Inflammation • worsening of the glaucoma

17. SLT vs. ALT • SLT incorporates "cold laser" technology Which Results less thermal damage to the trabecular meshwork architecture than that caused by the argon laser. • SLT achieves isolated destruction of the pigmented trabecular meshwork cells. There is minimal or no thermal or collateral damage to the surrounding non-pigmented cells because the energy output during SLT is 100 times less than that of ALT, and the pulse duration is much shorter. • Endothelial membrane formation on the trabecular meshwork, usually found in eyes treated with ALT, is not typically observed after SLT.

18. SLT vs. ALT • ALT produces crater formation, coagulative damage, fibrin deposition and disruption of trabecular beams and endothelial cells. Eyes treated with SLT do not show these findings, and the general structure of the trabecular meshwork is preserved. The lack of thermal and structural damage to the trabecular meshwork makes SLT potentially repeatable. • Precise Targeting Not Required for SLT.Since Selective Laser Trabeculoplasty depends on the laser parameters for targeting the pigmented cells, it is not necessary to have a small spot size or to precisely target a site in the trabecular meshwork as compared to traditional Argon Laser Trabeculoplasty.

20. How SLT performed • Pre-Op • Preoperatively, careful goinoscopy should be done to visualize the trabecular meshwork and plan the treatment area. The procedure is done with the Lumenis Selecta laser system. • Preoperative medications consists of a drop each of lopidine or Alphagan and topical anesthesia. A Goldman, three-mirror goniolens is placed on the eye with methylcellulose. The aiming beam is focused onto the pigmented trabecular meshwork. • During • Treatment is done in single-burst mode, placing 50 ± 5 contiguous, but not overlapping, 400-micrometer laser spots along 180 degrees. Bubble formation is monitored with each pulse. In cases with significant variation in trabecular pigmentation, the pulse energy is decreased if bubble formation occurred as described above. • Post-Op • After laser treatment, prednisolone acetate 1% is administered and continued n the treated eye four times daily for four to seven days.

21. References: • http://www.ophthalmic.lumenis.com/ • http://www.eyeworld.org • http://www.eyecentrerivercity.com.au/ • http://archopht.ama-assn.org/ • http://www.revophth.com/ • http://www.revoptom.com/ • http://www.mpomg.com/ • http://sdhawan.com/ • http://wikipedia.org/ • http://www.glaucomaslt.com/ • http://www.drjindra.com/

22. Thanks For Your Attention !