Where to stage the treatment

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Most people will treat the inferior fundus at the first session. Treatment in this area tends to cause fewer symptoms because the inferior fundus corresponds to less useful visual field. Treating this area first also ensures that it is treated in the event that a hemorrhage occurs; the blood tends to settle inferiorly and preclude further treatment. Subsequent treatments will then fill in nasally, superiorly and temporally. Because there is a sense that treating temporal to the fovea is most likely to exacerbate macular edema, it is a good idea to close the temporal loop in at least two steps.

Figure 10 shows how you might treat over two or three sessions. The three-session approach is probably the safest for patients who have early disease and for whom there is no time pressure.

Figure 10 shows how you might treat over two or three sessions. The three-session approach is probably the safest for patients who have early disease and for whom there is no time pressure.

Figure 10. Suggested two- and three-stage PRP patterns. (Reproduced, with permission, from Folk JC, Pulido JS, Ophthalmology Monographs 11: Laser Photocoagulation of the Retina and Choroid, American Academy of Ophthalmology, 1997.) By the way, this is a great book for laser treatment in general—lots of timeless info about lasering many different diseases.

One of the more difficult things about treating proliferative disease is that, as a conscientious physician, you may find yourself empathizing with your patient in terms of their absolute hatred of panretinal photocoagulation. It can be especially rough if they want to forego retrobulbar anesthesia for whatever reason—you can end up feeling every spot with them. All of this can make you want to try to "help them" by doing the least amount of PRP possible, and it can be easy to grossly undertreat patients by doing this.

Unfortunately, treating proliferative retinopathy usually means you have to be cruel to be kind, and unless you are absolutely convinced that the proliferative disease is mild, you need to harden your heart a bit and put in the appropriate treatment. The next chapter will discuss all sorts of strategies to minimize the patient's discomfort and make the process easier, so you can get the right amount of treatment in with the least amount of pain for both of you.

(If this blue box makes no sense to you, please check the level of your empathy tank before it is too late.)

References and Suggested Reading

1. Kaufman SC, Ferris FL, 3rd, Seigel DG, Davis MD, DeMets DL. Factors associated with visual outcome after photocoagulation for diabetic retinopathy. Diabetic Retinopathy Study Report #13. Invest Ophthalmol Vis Sci 1989;30:23-8.

2. Early photocoagulation for diabetic retinopathy. ETDRS report number 9. Early Treatment Diabetic Retinopathy Study Research Group. Ophthalmology 1991;98:766-85.

3. Reddy VM, Zamora RL, Olk RJ. Quantitation of retinal ablation in proliferative diabetic retinopathy. Am J Ophthalmol 1995;119:760-6.

4. Aylward GW, Pearson RV, Jagger JD, Hamilton AM. Extensive argon laser photocoagulation in the treatment of proliferative diabetic retinopathy. Br J Ophthalmol 1989;73:197-201.

5. Margolis R, Singh RP, Bhatnagar P, Kaiser PK. Intravitreal triamcinolone as adjunctive treatment to laser panretinal photocoagulation for concomitant proliferative diabetic retinopathy and clinically significant macular oedema. Acta Ophthalmol 2008;86:105-10.

6. Shimura M, Yasuda K, Nakazawa T, Kano T, Ohta S, Tamai M. Quantifying alterations of macular thickness before and after panretinal photocoagulation in patients with severe diabetic retinopathy and good vision. Ophthalmology 2003;110:2386-94.

7. Blankenship GW. A clinical comparison of central and peripheral argon laser panretinal photocoagulation for proliferative diabetic retinopathy. Ophthalmology 1988;95:170-7.

Friberg TR. Laser photocoagulation using binocular indirect ophthalmoscope laser delivery systems. Ophthalmic Surg Lasers 1995;26:549-59.

Folk JC, Pulido JS. Laser photocoagulation of the retina and choroid. San Francisco: American Academy of Ophthalmology, 1997.

Fong DS, Ferris FL. Practical Management of Diabetic Retinopathy. American Academy of Ophthalmology Focal Points 2003;21.

Davis MD, Blodi BA. Proliferative Diabetic Retinopathy. In: Ryan SJ. Retina, 4th ed. Philadelphia: Elsevier Mosby, 2006:v.2, pp 1285-1322.

Neubauer AS, Ulbig MW. Laser treatment in diabetic retinopathy. Ophthalmologica 2007;221:95-102.

Bloom, SM, Brucker, AJ. Laser Surgery of the Posterior Segment. Philadelphia: Lippincott Williams & Wilkins, 1997.

ch. 15 / Pain Control for PRPs 159

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Doc, at Least It's Not as Bad as Having a Baby: Pain Control for PRPs.

Pain control can be a real problem, especially on a busy clinic day, when all you want to do is cook some retina and move on. It is a good idea to slow down and deal with this thoroughly, though, for three reasons:

2. It is easier to get patients to return for follow up if the experience is not awful.

3. When patients sit around waiting for their endocrinology appointment, they will compare your treatment to the treatment that the other diabetics get. They will dump you if they find out that someone else makes the experience more pleasant than, say, the average Inquisition.

It may well be that as new laser technologies and new laser techniques are brought online, the whole issue of pain control will become much less of a problem. For instance, if gentler techniques such as the micropulse laser mentioned in Chapter 3 are proven to be effective in treating proliferative disease, then perioperative pain will be minimal. New delivery systems that can automatically apply multiple burns in rapid succession may also be helpful. However, new technology tends to be very expensive, and techniques that try to get by with less treatment than traditional ETDRS and DRS protocols are still investigational. As a result, this chapter will assume that you are doing traditional treatment with traditional tools.

There are a number of variables you can manipulate to make things more comfortable. The first is just to do what was mentioned in Chapter 7: Try to mentally put yourself in the patient's position, and try to anticipate what will scare them or make them uncomfortable. Always inform them about what you are about to do, and try to keep up a calm, soothing chatter while you are doing it—in other words, be a junior hypnotist.

Next, make sure the topical anesthesia has not worn off—especially during a long session. Sometimes the patient can't distinguish the difference between surface discomfort from the lens and pain from the laser. Often the simple act of giving the patient a break as you add more topical anesthesia will help them reset their pain threshold and allow you to get through the procedure.

It can also help to spread the treatment out over multiple sessions, perhaps putting in a few hundred spots at each session if the nature of their disease will let you get away with it. This approach is usually too inconvenient, especially if patients or family members have to take time off of work for each treatment, but this can work well for some patients as long as the proliferative disease is not progressing.

Some doctors feel that systemic medications will help. You can try anxiolytics or pain medicine by whatever route you feel comfortable. However, when you start tickling the long ciliary nerves it seems as though no amount of systemic medication can help. Nevertheless, remember that you have the option of using systemic treatment, and you will find an occasional anxious patient who does much better with a hit of Xanax while they are dilating.

There are also some variables on the laser you can play with. The two simplest things are to decrease the spot size and decrease the duration. Some lasers can go down to 0.02 seconds on the duration; this seems to help decrease the discomfort.1 Remember the warnings in the chapter on laser wrangling, though. When you decrease the duration, you will have to compensate by turning up the power. This, in turn, means that there is less time for the heat to spread out in the tissues, and you may be more likely to get a hot burn if you are not paying very close attention to what you are doing—especially if you are also using a small spot and there is a lot of pigment variation in the fundus. You may want to get comfortable with longer durations first, and once you have a more intuitive sense of how the retina responds to your laser you can try going to these much shorter durations.

Also, as mentioned in the previous chapter, you will notice that patients will sometimes complain of a great deal of pain in one location of the fundus and have less pain in another. Most of the time you can correlate this with the location of the various ciliary nerves; for instance, pain is especially common near pigmented areas between the tributaries of vortex veins. Sometimes the phenomenon is random, and the patient will jump as you are treating a nondescript area of the fundus. You can always treat the less painful areas first and save the more painful ones for fill-in treatment, if necessary.

By the way, there is a situation in which the technique in the previous paragraph can burn you, as well as the patient. If, in follow up, you are seeing a patient who has an odd, patchy PRP pattern, you can bet that the previous treating physician did this very thing as the laser was being placed. If you need to do a PRP fill on such a patient, it is guaranteed that every single one of your spots will be quite painful, no matter how you tweak the settings— and the patient will be convinced that you are a monster and their previous doctor was a saint. It always helps to warn patients that subsequent lasers can be more painful so they understand what is going on.

Another technique is to slow down the rate of fire. Sometimes, rapid laser treatment results in temporal summation and can make the experience more miserable. Slowing down the treatment a lot, however, can make the laser really drag on and on, and it may be better to move on to some sort of anesthetic injection if both you and the patient are getting frustrated by the long process.

If you do need to do regional anesthesia, the standard approach tends to be either a retrobulbar or peribulbar injection, depending on your preference. There is a general sense that a retrobulbar injection is more effective and faster, whereas a peribulbar technique may be safer (although it takes longer to work, and may require multiple injections, which can obviate any advantages). A full discussion is well beyond the scope of this book—in short, do what works best for you based on your experience.

In addition to full-blown orbital anesthesia, you can occasionally get by with more localized injections. For instance, after numbing the conjunctiva with a pledget, you can place subconjunctival anesthesia, which will do a fairly good job of numbing the anterior portion of a quadrant of the fundus. Another option is to try a sub-Tenon's approach. Although a sub-Tenon's injection is unlikely to give you complete anesthesia of the globe, it can be very effective for treating a larger quadrant of the fundus, and may be safer than a retrobulbar injection. These are not techniques you are likely to use often, but they are good things to keep in your toolbox.

Of course, you need to clearly state the risks of performing local anesthesia, such as globe perforation, retrobulbar hemorrhage and even diplopia from inadvertent muscle injection. All of these things are unlikely, but if you treat a lot of diabetics, you will do a lot of retrobulbar injections, and the odds will tend to catch up with you at some point. You do not want such a complication to come as a surprise to the patient. Usually, however, if the patient is miserable from the laser they will be more than willing to accept the small risk of a numbing shot.

Oh, and don't forget to find out if the patient is on Coumadin. If they are, you may want to check an INR to make sure things are not too out-of-control prior to an injection (more on this in Chapter 25). It is very easy to forget to do this when things are busy, but a busy day is exactly when the retina gods will make you try to remember how to decompress an orbital hemorrhage in an anticoagulated patient...

Hey, sorry to throw in two text boxes that are only two paragraphs apart, but it is worth pointing out that if a patient has a really high INR, yet you still need to get some laser in fast (i.e., neovascular glaucoma), it is a great time to use the less invasive anesthesia techniques mentioned in the preceding blue box.

Also, remember that people who have had Lasik or cataract surgery may now be refractively emmetropic, when in fact they still have big, pear-shaped eyes. Do not assume that an aggressive placement of your retrobulbar needle is safe just because patients are not wearing thick myopic spectacles. A needle through the retina tends to be worse than any degree of proliferative disease. Duh.

Finally, you should also have appropriate resuscitation equipment available, and your staff should check on patients shortly after performing an anesthetic injection in the office. Remember that if your anesthetic gets into the brain pan you do not want the patient to be alone when they stop breathing. Be especially alert for any patient who starts to complain of trouble swallowing or breathing within a few minutes of the injection—watch them carefully, and do not assume that they are just having a vasovagal response. Interesting factoid: There has been at least one case reported wherein a patient developed respiratory arrest from a retrobulbar, and when the patient recovered, he said that he was awake the whole time—he just could not talk or move during the episode.2 Watch your language!

Whatever method you use to make your patients comfortable, your most useful tool is your clinical experience. It will not take long for you to realize that some patients do extremely well and other patients are likely to have real problems with the laser—and you will get a sense about which category a patient is in just by interacting with them well before you sit them down in the laser suite. (Insert, once again, the standard stereotype about the burly, tattooed male being unable to tolerate much of anything).

You will likely find that a patient's ability to tolerate the laser decreases as you put in the treatments. Many patients can do well with the first two treatments, but end up needing an injection with the third. Just be flexible.

Also, recognize that some patients are unable to decide between the risk of an injection and the pain of the laser. Although modern medicine emphasizes informing patients and "letting them decide for themselves," this is a situation in which you may want to gently suggest that they try an injection one time to see how they like it. They will usually choose to use an injection henceforth, once they see how easy it is, and you will have avoided a very, very long session at the laser. (Understand that this is not a situation in which saving the doctor's time is more important than the patient's safety. Instead, what you are avoiding is a long, tedious session wherein both the doctor and the patient can become toxic. This is bad for everyone, and can lead to an unhappy patient who does not return for follow up, which is the worst outcome. In this case, the overall karma allows you to revert to being a typical movie doctor from 1948 and just telling the patient what to do—not a good idea in general, but very effective when used sparingly.)

Some doctors will routinely give retrobulbar injections to everyone because they make treatment faster. Although this does rev up the assembly line, the sheer number of injections inevitably increases the risk of a bad complication. Also, you will find that patients who have been in such a practice are often very grateful if they end up going to a doc who gives them a choice, rather than automatically giving them a retrobulbar. It is much better to take a little more time to sit the patient down and let them see what a PRP is like. This way, you can explain in advance the potential risks of regional anesthesia, and they can decide for themselves if they want to bail out and get a numbing shot. You will find that many patients can tolerate a fairly stiff dose of laser without automatic injections—it takes a little more time, but most patients appreciate being given the chance to decide (preceding paragraph notwithstanding!).

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