Download Bifocals for myopia – Guyton DL 11 16 2015

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Rapid progression of myopia can be successfully treated with
+3.00 D bifocals having high-placed flat-top segments
David L. Guyton, MD - November, 2015
(My comment: It is important to understand the frustration that an optometrist feels
about this difficult situation. I wish that the “plus” could be started before the person’s
Snellen goes below 20/40, and refractive status, below -1 diopter. But that would require and
education for the person, to truly understand how critical it is to start wearing the plus at that
The issue of wearing a plus at that point, is that if you do not wear it, your refraction goes
down at a rate of -1/2 diopter per year, for each year in school. Yet the patient is considered
to be to ignorant to understand that issue – and the life-time consequences of choosing to
ignore it. Dr. Guyton is a great ophthalmologist and friend. But I must disagree with him on
empowering the person to take more, and perhaps complete control of his distant vision, by
systematic wearing of a plus 3, during the years in school. Otis S. Brown)
History: Two large clinical trials attempting to use bifocals to slow the progression of myopia showed no clinically
significant reduction in such progression. The first trial was at the University of Houston College of Optometry1 ~30
years ago, in children 6-15 years old, using high-placed Executive reading adds of +1.00 D or +2.00 D placed 2 mm
below the pupil centers, and the second trial was in four schools of optometry coordinated by the New England College
of Optometry2 ~15 years ago, in children 6-11 years old, using +2.00 D progressive power lenses.
Critique: Because children accommodate so easily and reflexively through the upper portions of their glasses, there is
little incentive to raise their chins to use the lower portions of the glasses with either regular flat-top adds or progressive
power lenses. Also, reading adds of +1.00 to +2.00 D may not be sufficiently powerful to prevent accommodative lag,
which leaves the focal plane of images of near objects behind the retina.
Possible solution: Just as high-placed Executive or flat-top reading adds can be successful in the treatment of
accommodative esotropia, such high-placed adds can automatically ensure that the wearer looks through the add portions
of the glasses for most near tasks. Unless the reading material is held too close, such bifocal use of high enough power
can keep the ocular images focused on or in front of the retina, avoiding the images being formed behind the retina
where they can stimulate the progression of axial myopia.
Experience: For 20-30 years, I have prescribed such high-placed flat-top adds, usually +3.00s, in children with rapidly
progressive myopia, with the top of the segments splitting the pupils in straight ahead gaze (see attached instructions to
the optician). The results, not yet formally tabulated or tested for significance, have subjectively been very gratifying
indeed. Progression of the myopia has usually been decreased from ~1.00 D per year to the range of ~0.25 to 0.37 D per
year with this technique.
Problems:
[1]
Holding the reading material too close, inside the far point of the bifocal segments, defeats the purpose of the
bifocal treatment. The child should be encouraged to hold the reading material as far away as he or she can see it clearly,
or the reading adds may need to be increased to as high as +4.00 D.
[2]
Children are using computers more and more in school, and these are difficult to use with highly-placed highpower bifocals. Laptop or tablet computers can be often be used successfully whereas desktop computers cannot be.
Alternatively, separate “computer” glasses may be prescribed, with the top segments focused for the distance of the
computer screen, and the high-placed reading adds focused for the usual nearer reading distance.
[3]
Peer pressure to go into contact lenses often brings a halt to the bifocal treatment, but usually this is at 12-14
years of age, where rapid progression of the myopia has naturally slowed.
Clinical trials needed: To date I know of no clinical trial of highly-placed, high-power bifocal segments (of at least
+3.00 D) for the treatment of rapidly progressive myopia. Interested clinicians and/or investigators may well find
successful results with this technique, as I have.
[1]
[2]
Grosvenor T, Perrigin DM, Perrigin J, Maslovitz B. Houston Myopia Control Study: a randomized clinical trial. Part II. Final report by the
patient care team. Am J Optom Physiol Opt. 1987;64(7):482-98.
Gwiazda J, Hyman L, Hussein M, Everett D, Norton TT, Kurtz D, Leske MC, Manny R, Marsh-Tootle W, Scheiman M. A randomized clinical
trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest Ophthalmol Vis Sci.
2003;44(4):1492-500.
The Krieger Children’s Eye Center at The Wilmer Institute
Pediatric Ophthalmology and Strabismus
Wilmer 233, The Johns Hopkins Hospital, Baltimore, MD 21287-9028
Phone: 410 955-5492
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Bifocal Instructions
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To the Optician:
We have prescribed bifocals for our pediatric patient. The need for and the type of bifocals in children with strabismus
or rapidly progressive myopia have some specific and unique requirements which are different from the usual adult
applications.
Please note the following, as indicated in the diagram above:
1) The top edge of the bifocal segments should bisect both pupils when the eyes are looking at a distant object in the
straight ahead position.
2) 25-35 mm flat-top segments are acceptable.
Also note the following:
Encourage selection of a style with the eye near the geometric center of the lens, both vertically and horizontally. Also
avoid frames with a sweat bar, which often ride too low.
Frames with non-joined adjustable nose pads are not satisfactory as they rarely stay in place firmly enough. This results
is the bifocal segment being positioned too low. A solid nose piece such as a form-fit or a saddle bridge is recommended.
The Unifit is also acceptable.
Bows that have a wrap-around effect, such as a riding bow, are usually preferable to bows that have little support behind
the ear. It is important that the spectacles not slip down.
Please contact us at the number above if you have any questions or comments. Thank you.
DGH/AC/DLG 7/2015