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Round table: Pediatric ophthalmologists debate merits of progressive bifocals
OSN Pediatrics/Strabismus Section Editor Robert S. Gold, MD, leads section members in a robust round table discussion on when and whether to prescribe progressive bifocals for children.
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Robert S. Gold, MD: Let’s talk about bifocals in pediatric ophthalmology.
Erin D. Stahl, MD: In my aphakic patients, I typically put children in a lower single-vision bifocal, and I have started putting some of my older kids into progressive lenses. I have recently wondered about starting to do it in my younger kids and the timing of that.
Gold: Not in aphakia, but in cases of accommodative esotropia with high accommodative convergence/accommodation (AC/A) ratios, we use progressive bifocals in the great majority of patients whose parents would like to pay for them. They are more expensive; esthetically, they are more pleasing. We elevate the optical center of the bifocal a couple of millimeters to force them to be in that lower segment. We have had great success in our practice doing it. Many opticians do not understand the process, so sometimes you have to talk to an outside optician when they get the prescription. We use both standard types of bifocals and the progressive, and we have had very good success.
Anthony P. Johnson, MD: I just looked up in the current Basic Clinical Science series, and the flat top — the conventional wisdom — is still recommended, but the choice of the progressive is mentioned. The thing that changed my focus on this was a mom who asked about getting no-line bifocals for her little girl who was 5 or 6 years old. My answer was, “Well, we have the most experience with this flat-top design, and progressives are more expensive, and because of that there’s really not that much experience with them.” And she looked at me very seriously and said, “If there’s not a reason not to do it with a progressive, don’t worry about the money. I’ll take care of that.” That really opened my eyes. Why wasn’t I recommending them? Of course, it was what I was taught and what I had done for probably 15 years. But since then, I have realized that there is a huge optical difference if they have a progressively increasing AC/A ratio. Depending on distance, it only makes sense optically and physiologically to have different amounts of add for those. Opticians are often uncomfortable with that, and I always err on the side of 0.25 D or 0.5 D more than they need because they often never get into the full amount of it anyway, and it depends on the frame design, and that sort of thing. But I think that it is helpful for them.
M. Edward Wilson, MD: Dr. Stahl mentioned patients with aphakia or pseudophakia. In those patients, whether they are in a contact lens or an implant, I start a bifocal around the third birthday, sometimes a little earlier, sometimes a little later depending on the child, but the first bifocal I give is often a lined bifocal, so that I can assess whether they have learned to use it or not. But as soon as they get into the age of peer pressure, the parents start asking about the look of the glasses, and their friends are asking why it has that line in it, then I am quick, once they are a good bifocal user, to switch them to a progressive. I think progressives, once children adapt to them, have a big advantage, and an aphakic or pseudophakic patient is driven to use the bifocal.
Now, in accommodative esotropia patients with a high AC/A, they may not be as driven to use the bifocal, and then there is some advantage too. As soon as they drop below the line, they get the full power of the bifocal and they begin to recognize the benefits of fusion that they might not recognize with a progressive until they get all the way to the bottom when they have to raise their chin up. So I am slower to change to a progressive in this population. But as soon as they are asking, “When are we going to get rid of the bifocal?” and I am not ready to get rid of it, then I change them to progressive because it looks more normal and they are ready, probably, to adapt to it.
Roundtable Participants
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Moderator
- Robert S. Gold
- Kenneth P. Cheng
- Anthony P. Johnson
- Erin D. Stahl
- Rudolph S. Wagner
- Roberto Warman
- M. Edward Wilson
Rudolph S. Wagner, MD: I agree. I use the progressives frequently in the accommodative high AC/A types, and I think that they work well. I think you have to pay attention to exactly what Bob said about making sure it is higher. That will probably solve some of the issues, if you have the optician working along with you to get it at the right positioning.
Roberto Warman, MD: I agree. I would love to put progressives on more patients. I guess it all depends also on your patient population. My biggest frustration is the horrendous glasses that my patients come with, with useless bifocals, because they get them at the cheapest possible place. To jump to progressives from there, it is, for many patients, just not an option. I hope we can get a better solution to this with time. I would love to prescribe more progressives. At least let’s get the bifocal segment height in the right place.
Kenneth P. Cheng, MD: I have a couple of questions. I have always stuck with that traditional teaching of a flat-top bifocal put at the bottom edge of the pupil for high AC/A ratio accommodative esotropia because I never realized that if those kids wanted fusion enough, that they would look through the bifocal if it were placed lower. When it is put up high and it is a flat top, it is automatic because when you are holding things up close, you have to look down. So these children, a large number of them, must want fusion badly enough in order to look down far enough to use a bifocal. To me, that is a revelation. But getting back to what Roberto said, oftentimes kids come into the office with glasses hanging down so far on their nose that they look over the tops of them, much less find a bifocal lens down low. There is a tremendous amount to be said about a really skilled optician having a wide range of frames available in order to get these kids in the right glasses. So I will start trying some progressive bifocals after our discussion today.
Johnson: I never measure anything except distance and near, but it stands to reason that these patients are probably not all homogeneous, and where do they start to develop a little bit of the microesotropia?
Cheng: Parents complain to me all the time about seeing crossing of the eyes at the dinner table, and that is that intermediate range where they do not have any help.
Johnson: I think that it is because we have been trained to measure distance and near. Nobody is measuring at 6 feet, 8 feet, 10 feet, 14 feet, whatever. All of us around this table are presbyopic. Everybody is in progressives, but for a different reason. Personally, I am incredibly sensitive to not having enough add power. If we had just the flat-top design, you go from being in focus at distance or being in focus at one-third of a meter, and nothing in between. Anything in between is too far for the add and too close for the distance; that would drive me crazy.
Cheng: These patients can see. They do not have the blur. They just have suppression, and I do not know whether they care about suppression because how many kids do you have who care whether they wear their glasses for accommodative esotropia? They are perfectly happy reading with their eye crossed. We hate it. The parents hate it. It is probably bad for them. But I do not think that they feel that it is blurry, or they do not feel that degradation of vision quality that you do.
Johnson: I think that we need to approach it from the standpoint of what is best for everybody. We are always going to be dealing with a population that is not motivated to patch or to keep their glasses in the right position, but because we cannot measure who is a discriminator and who is not, we need to approach it with what is best for all of them at all distances.
Cheng: This fascinates me because it is something I have not done. For example, I wear contact lenses, and I am fine. I am still, believe it or not, accommodating some fair amount. However, I had a pair of glasses made that are plano/plano, a 1.5 progressive, and the progressive in these is just a little high, and it drives me crazy. I cannot wear them because I hate the blur. You do not have kids who are more resistant to their glasses with the progressive? That is something different and out-of-the-box thinking.
Wagner: I was thinking along the same lines as Tony about this variability of the measurement of esotropia at different distances that we never pay attention to. How many kids are going to get out of their bifocals, by either method? I am not so sure there is a big difference. I see kids who do get out of them, and I see some kids who still have a greater esotropia at near even when they are teenagers.
Cheng: These patients might do better because I suspect that much of the time they will not be using the full add power, and maybe then they will be using the intermediate range. Maybe those are the patients who will adapt more easily to weaker bifocals.