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Ophthalmic Professional

Article

A Guide to Assisting Surgeons in Glaucoma Procedures

Tips for how to best aid a physician during laser operations for glaucoma patients.

Ophthalmic Professional July 1, 2013 Vol 2, Issue July 2013

As part of an inter-professional team, ophthalmic technicians play a vital role in assisting surgeons by obtaining information needed to understand challenges confronting glaucoma patients. Often, technicians encounter patients with difficulty complying with their ophthalmic treatments. Allergies, medical conditions like arthritis and diabetes, forgetfulness, difficulties instilling the drops, or affording medications may also interfere with patient compliance.

Primary open angle glaucoma is the second most common cause of blindness worldwide.1 It is characterized by structural changes of the optic nerve associated with specific visual field defects. Fortunately, vision loss from glaucoma can be limited through early detection and intraocular pressure control,2 which reduces the rate of new damage.3, 4, 5

Medications are widely used as first-line therapy. However, the role of laser trabeculoplasty within the treatment algorithm is changing. In 1979, Wise and Witter,6 showed favorable findings of Argon trabeculoplasty (ALT) for lower IOP control.7 Due to the lasers’ strong safety profile, portability and efficiency, some physicians consider earlier intervention to treat patients. At any point during which a glaucoma medication may be prescribed, laser trabeculoplasty can be offered to patients as initial8 or adjunctive therapy. Lasers can be used prior to cataract surgery in glaucoma patients who need better IOP control, to reduce the medication burden in patients controlled on one or more topical medications, or those receiving steroid intravitreal injections.9, 10 A 25-30% reduction of pressure is documented in many studies.11

Surgeons may choose from among several kinds of lasers (see Figure 1).9 They may opt to treat 90 to 360 degrees of the trabecular meshwork12, 13 in one or more sessions.

FIGURE 1.

PARAMETERS ALT 488/514 nm SLT Nd:Yag 532 nm MDLT 810 nm TLT sapphire 790 nm
Spot Size 50 microns 400 microns 75-200 microns 100 microns
Duration 0.1 sec 3 ns 0.2 sec 5-10 ns
Wavelength 300-1000 mw 0.4-1.2 mj 1-2 watts 30-50 mj
Endpoint Blanching Tiny Bubbles    
ALT: Argon Laser Trabeculoplasty MDLT: Micropulse Diode Laser Trabeculoplasty SLT: Selective Laser TrabeculoplastyTLT: Titanium Sapphire Laser Trabeculoplasty

Mechanism of Action

While lasers’ mechanism of action is not well understood, theories include mechanical, biochemical and cellular effects.14, 15, 16 Ultimately, increased flow through the drainage channels is improved and the pressure is reduced.

Efficacy of Treatment

The goal is to apply the minimum amount of treatment needed to achieve the desired therapeutic benefit. Fifty spots per 180 degrees are performed per treatment area. A variety of studies report the comparative efficacy among the various lasers.17, 18

Setting up the Laser

Ophthalmic staff prepare for laser treatments with proper installation of the laser onto the slit lamp or the freestanding unit. The smart key must be installed before the diode laser can be functional. A dedicated room should be used and there should be a laser safety sign mounted on the door when the laser is in use. Individuals in the laser suite should be sure to wear protective eyewear according to the laser wavelength. Then, check that the laser machine is turned on and in working order. Periodic laser inspections and staff training sessions are necessary to properly determine the laser’s operability. Understanding laser treatment’s risks and benefits enable ophthalmic technicians to increase patients’ satisfaction and comfort with the procedures.

Seeing the Effects

Systematic procedures and confirmation of procedural algorithms can help reduce errors and ensure patient satisfaction.

The full effects of laser treatment are often seen within four weeks, but studies have shown that it may take longer to reach the lower desired pressure. Immediate reduction of pressure post-laser is often due to the medical therapy to avoid postoperative pressure spikes, and not the effects of the laser. The postoperative pressure should not be higher than the pretreatment pressure. Ultimately, it takes time for the modulation to occur in the trabecular meshwork and achieve desired IOP.

Preperation Check List

1 Prior to the surgeon’s entering the laser suite, carry out the following checks:

a. Verify signed and checked surgical consent.

b. Verify patient’s name and eye to be treated. Since 90-360 degrees can be treated, it should be documented.

c. In ambulatory surgical or hospital settings, collect vital signs.

2 Mark the correct surgical eye.

3 Administer pre-operative medications in advance of the procedure according to the orders:

a. Pre-treatment with Pilocarpine 1% -2% or 4 % q 5 minutes x 1-3

i. Instill drops to help in visualizing the trabecular meshwork into the operative eye. Use lower doses of Pilocarpine for lighter irides and higher for darker irides.

ii. Some surgeons choose not to pre-treat with Pilocarpine due to side-effects such as eyebrow ache, shift of refractive error and possible retinal detachment in high risk individuals.

b. Topical Iopidine, 0.5-1%, or Alphagan/Brimonidine drops are used to decrease the possibility of post-operative laser spikes.

i. These medications help to decrease the intraocular pressure spike.

ii. Pressure spikes are more likely to occur in patients receiving 360 degrees of treatment.12, 19, 20, 21

4 Set out lenses:

a. Lenses should be cleaned:

i. Clean lens(es) between patients.

1. Place cleaned Ritch, Latina (SLT), or Goldman 3-4 mirror lenses near the laser. (see lens types)

ii. Place viscous gel into lens’s concave portion.

1. There are different products on the market such as goniosol or new smaller individual packets of lidocaine jelly.

2. Make every effort to avoid bubbles. Hint: Keep the viscous solution bottle inverted to eliminate air bubbles when filling the concave well of the lens. The solution protects the corneal epithelium from scratches.

5 TIME OUT: Upon surgeon’s arrival:

a. Ask the patient which eye is being operated upon.

b. Verify surgical eye and procedure.

c. Instill topical anesthetic in operative eye prior to surgeon’s placing lens in the eye.

d. Place sponge or elbow supportive products near the laser field so that surgeon can brace arm in order to deliver treatment.

e. If needed, assist patient in keeping forehead against the slit lamp headband during procedure.

6 Postoperative instructions per surgeon’s protocol

a. Repeat Topical Iopidine, 0.5-1%, or Alphagan/Brimonidine drops.

b. Non-steroidal anti-inflammatory agents (NSAIDs) minimize inflammation after SLT; anti-inflammatory steroids after ALT.11, 22

c. Instruct patients in medication use according to surgeon’s directions.

d. Verify the patient has a postoperative appointment scheduled at the office.

e. Check immediate postoperative pressure.

f. Clean up.

7 Return clinic appointment

a. Repeat medical history: verify medications, ask if photophobic, check vision, and pressure.

b. Rare complications of SLT include: corneal edema, sustained elevated IOP, hyphema or reactivation of Herpetic disease.9

Laser trabeculoplasty has been indicated in individuals for ocular hypertension or open angle glaucoma, but there is a growing body of literature to support use of SLT for other subtypes of glaucoma.9, 23

Providing information and education to office personnel about surgical procedures and their indications helps staff ease patients’ apprehensiveness and increase the quality of their care. OP

References

  1. Quigley, H.A., Broman AT, The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006; 90:262-7

  2. Quigley, H.A., Flower RW, Addicks EM, McLeod DS. The mechanism of optic nerve damage in experimental acute intraocular pressure elevation. Ivest Ophthalmol Vis Sci. 1980;19:505-17

  3. Sommer A., Tielsch JM, Katz J. Quigley HA, Gottsch JD., Javis J, et al. Relationship between intraocular pressure and primary open angle glaucoma among white and black Americans. The Baltimore Eye Survey, Arch Ophthalmol. 1991;109:1090-5

  4. Kass MA, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open angle glaucoma. Arch Ophthalmol. 2002;120:701-13

  5. Heljl A, Leske MC, Bengtsson B, Hyman L, Bengtsson B. Hussein M; Early Manifest Glaucoma Trial Group. Reduction of intraocular pressure and glaucoma progression: results from the Early

Manifest Glaucoma Trial. Arch Ophthalmol. 2002;120:1268-79.

  1. Wise, JG, Witter SL, Argon Laser therapy for open-angle glaucoma. A pilot study. Arch Ophthalmol. 1979;97:319-22

  2. The Glaucoma Laser Trial Research Group. The Glaucoma Laser Trial (GLT) and glaucoma laser trial follow up study: 7 Results. Glaucoma Laser Trial Research Group. Am J. Ophthalmol. 1995;120:718-731

  3. Rachmiel R, Trope GE, Chipman ML, et al. Laser trends with the introduction of new medical treatments and selective laser trabeculoplasty. J Glaucoma. 2006:15:306-309

  4. Realini, T, Selective Laser Trabeculoplasty. J Glaucoma. 2008; 17: 497-502.

  5. Bozkurt E, Kara N. Yazici AT, et al. Prophylactic selective laser trabeculoplasty in the prevention of intraocular pressure elevated after intravitreal triamcinolone acetonide injection. Am J. Ophthlamol. 2011; 152:976-981

  6. Latina MA, Sibayan SA, Shin DH, et al. Q switched 532 nm Nd: YAG laser trabeculoplasty (selective laser trabeculoplasty): a multicenter, pilot clinical study. Ophthalmology. 1998;105:2082-2088, discussion 2089-2090

  7. Chen E., Golchin S, Blomdahl S. A comparison between 90 degrees and 180 degrees selective laser trabeculoplasty. J Glaucoma 2004;13:62-65,

  8. Song J, Lee PP, Epstein DL, et al. High failure rate associated with 180 degrees selective laser trabeculoplasty. J Glaucoma 2005;14:400-408

  9. Stein JD, Challa P, Mechanisms of action and efficacy of argon laser trabeculoplasty and selective laser trabeculoplasty. Curr Opin Ophthamol. 2007;18:140-145

  10. Van Buskirk EM, Pond V, Rosenquist RC, et al. Argon laser trabeculoplasty. Studies of mechanism of action. Ophthalmology. 1984;91:1005-1010

  11. Murthy S Latina MA, Pathophysiology of selective laser trabeculoplasty, International Ophthalmology Clinics 2009 49:89-98

  12. Goldenfeld M Melamed S. Simon G, Den Simon GJ. Titanium sapphire laser trabeculoplasty versus argon laser trabeculoplasty in patients with open angle glaucoma. Ophthalmic Surg Lasers Imaging 2009;40:264-269

  13. Fudemberg SJ, Myers JS, Katz LI. Trabecular meshwork tissue examination with scanning electron microscopy: a comparison of micropulse diode laser (MLT), selective laser (SLT). Available at www.iovs.org and argon laser (ALT) trabeculoplasty in human cadaver tissue. Invest Ophthalmol Vis Sci. 2008; 49E1236

  14. Damji KF, Shah KC, Rock WJ, et al. Selective laser trabeculoplasty v argon laser trabeculoplasty: a prospective randomized clinical trial. Br J Ophthalmol. 1999;83:718-722

  15. Nagar M. Ogunyomade A., O'Brart DP et al. A Randomized, prospective study comparing selective laser trabeculoplasty with latanoprost for the control of intraocular pressure in ocular hypertension and open angle glaucoma. Br J Ophthalmol. 2005;89:1413-1417

  16. Lai JS, Chua JK, Tham CC, et al. Five year follow up of selective trabeculoplasty in Chinese eyes. Clin Experiment Ophthalmol. 2004;32:368-372

  17. Martinez-de-la-Casa JM, Garcia-Feijoo J, Castillo A, et al. Selective vs argon laser trabeculoplasty: hypotensive efficacy, anterior chamber inflammation, and post operative pain. Eye 2004; 18:498-502.

  18. Meyer JJ, Lawrence SD, What's new in laser treatment for glaucoma?, Current opinion 2012., www.co-ophthalmology.com Lippincott Williams and Wilkins

 

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Dr. Olivier
is Associate Clinical Professor at John H. Stroger, Jr., Hospital at Cook County, Midwestern University, and Olympia Fields Osteopathic Hospital. She is currently the CEO and founder of Midwest Glaucoma Center, P.C.

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