Adult patients receiving vision therapy usually fall
into one of three groups: those with asthenopia, those with strabismus with or
without diplopia and those with amblyopia. Patients with binocular problems
find us on the Web, are referred to us for vision therapy or are identified in
Being in the heart of Manhattan, most of our vision
therapy patients are adults. Those referred to us usually come from pediatric
ophthalmologists, other ophthalmologists and, occasionally, optometrists.
Interestingly, our largest source of referred patients is ophthalmologists.
Higher demands on accommodation/vergence
The world has changed — it has become a
two-dimensional near vision task world dependent on reading, desk work and
computer viewing. The visual system was not designed to perform activities that
lack the stereoscopic cues. Today’s visual demands require an
accommodative and vergence system that can make accurate and sustained
responses without fatigue.
Patients who perform a lot of close work or reading or
who use computers extensively are more prone to develop signs and symptoms from
accommodative or vergence dysfunction. Symptoms associated with accommodative
and vergence anomalies include blurred vision, headache, ocular discomfort,
ocular or systemic fatigue, diplopia, motion sickness and loss of concentration
when performing a task.
In-office therapy: The patient is wearing liquid crystal glasses to separate the right and left views while viewing a stereoscopic picture with four numbers. One number appears in greater depth, like the Titmus circle test. The patient responds to the position of the stereo number (up, down, left or right). Correct responses result in positive reinforcement with a concurrent increase in fusional demand; incorrect responses result in negative reinforcement and a reduction in fusional demand. Thus, the patient controls the level of therapy.
Image: Cooper J
A high percentage of symptomatic computer workers have
subtle binocular vision problems whereby ocular discomfort increases with
computer usage. Similar findings have been reported for other populations who
perform sustained near work, such as students, accountants and lawyers. In
fact, asthenopia (after blur) is the second leading reason why patients 15 to
45 years old make appointments to see an eye doctor.
Computer vision syndrome has been described to be caused
by dry eye problems and uncorrected small refractive errors. There is almost no
scientific data to support this conclusion. In my experience, the leading cause
of asthenopia (blur, headache, double vision, tiredness, etc.) is secondary to
Convergence insufficiency occurs in about 5% of the
population. In an excellent study, Sheedy demonstrated that dry eye symptoms
and asthenopia had different symptomatology and can be easily differentiated.
Thus, symptoms associated with a computer in which the patient complains of
dryness, grittiness, or burning are usually due to dry eye, while complaints of
headaches, discomfort and blur are usually due to accommodative/vergence
The diagnosis can be easily be made with the Convergence
Insufficiency Clinical Trial (CITT) symptoms survey, cover test at near, near
point of convergence (NPC), positive relative accommodation/negative relative
accommodation and a measurement of fusional amplitudes.
The CITT symptoms survey is an excellent questionnaire
for practice management and identifying and quantifying asthenopia. Often when
measuring NPC or fusional amplitudes, repeating the tests will result in
asthenopia, grimacing or head retraction. These behavioral responses are almost
diagnostic of symptomatic accommodative/vergence anomalies.
Once identified, the optometrist should advise the
patient that these are muscle problems, not vision problems, and that glasses
are prescribed for vision problems and eye exercises solve muscle problems.
Recent evidence from a pediatric CITT study supports the
concept that prism glasses are no more effective than placebo glasses in
eliminating asthenopia. In addition, numerous studies including the CITT pilot
clinical trial have demonstrated that the most effective method of eliminating
convergence insufficiency symptoms is office-based vision therapy. Prism and
pushup therapy were no more effective than placebo therapy. Thus, we advocate
the only clinically proven treatment for asthenopia.
As a primary care practitioner, my treatment of
pediatric and adult patients with symptomatic accommodative and vergence
anomalies is the same: office-based vision therapy supplemented with home-based
computer exercises. One must improve accommodative amplitude and facility,
vergence amplitude and facility and then integrate them.
However, not all of our patients elect to participate in
in-office therapy supplemented with home therapy. For those patients who cannot
participate in office therapy, we prescribe the Home Therapy System (HTS)
computer program and pushup therapy. The HTS program allows our staff to
monitor the progress of our patients via the Internet. In addition, we have the
patients return to the office with performance printouts monthly. Success rates
are about 95% in motivated patients.
Treating adult amblyopes
We often see patients who have amblyopia that was never
properly treated when they were a child. These patients are concerned about
their vision because they only have one eye and would like to improve their
“lazy eye.” Most of these amblyopic patients have been told that
there is no treatment after the age of 6. This is not true and was supported by
the recent Amblyopia Treatment Studies supported by the National Eye Institute.
Generally, we treat these patients by fully correcting
all anisometropic and astigmatic errors, patching for 2 hours for milder
amblyopia (up to 20/60) and 6 hours for more severe amblyopia (worse than
20/60) (atropine or Cyclogyl [cyclopentolate HCl, Alcon] can be substituted for
patching in some cases) and home hand-eye tasks at an acuity level that can
just be seen. We usually prescribe the HTS amblyopia program. We see the
patients every 3 months until their vision plateaus. Success is much higher
than one would expect, with most patients achieving significant improvement. We
stop treating when a plateau is reached after 3-month blocks of treatment.
When patients ask what the oldest age of neurological
plasticity (oldest age of treatment) is, we tell them it is at death. If the
patient has anisometropic amblyopia we then eliminate suppression by either
in-office or home-based vision therapy.
Prism, vision therapy for strabismus
Strabismus may be divided into newly acquired vs.
infantile, paretic vs. non-paretic and intermittent vs. constant. Newly
acquired paretic strabismus patients need an appropriate workup.
We usually prescribe Fresnel prisms to either eliminate
or decrease the diplopia symptoms. Older paretic strabismus patients may
benefit from ground-in prism and supplemental vision therapy to enhance
We have treated several vertical deviations secondary to
decompensation of a vertical deviation with excellent success. Longstanding
intermittent deviations usually respond well to vision therapy to enhance their
We have treated intermittent hypertropes as large as 25
pd with about 6 to 9 months of therapy. The emphasis of treatment is
contraintuitive. You need to increase horizontal fusional ranges and then
systematically reduce the vertical prism in the glasses. If the deviation is
too large, surgery will improve the treatment results.
Exodeviations respond much better than esodeviations.
Large esodeviations are initially treated with surgery followed by vision
therapy to initiate binocular fusion. Fusion prevents future deviations.
Adult patients who have binocular problems are often
symptomatic and require treatment. They are usually highly motivated and easier
to work with than children. Contrary to conventional wisdom, these patients are
not too old to improve amblyopia, restore binocular vision in strabismus or
eliminate their asthenopia with vision therapy.
Both in-office and home therapy have their place in the
treatment regimen. These patients become enthusiastic and are important
referrers to your practice.
For more information:
- Jeffrey Cooper, OD, MS, is a clinical professor at the State
University of New York, College of Optometry. He can be reached at 539 Park
Avenue, New York, NY 10065; (212) 758-0772; fax: (212) 758-3532; e-mail:
firstname.lastname@example.org. Dr. Cooper has
a financial interest in the HTS system. He is the original designer of the
system, which is being used in National Eye Institute studies.
- Berqvist U, Knave B. Eye discomfort and work with visual display
terminals. Scand J Work Environ Health. 1994;20:27-33.
- Borsting EJ, Rouse MW, Mitchell GL, et al. Validity and reliability
of the revised convergence insufficiency symptom survey in children aged 9 to
18 years. Optom Vis Sci. 2003;80:832-838.
- Convergence Insufficiency Treatment Trial Investigation Group. A
randomized clinical trial of treatments for symptomatic convergence
insufficiency in children. Arch Ophthalmol. In press.
- Cooper J. Orthoptic treatment of vertical deviations. J Am Optom
- Cooper J, Duckman R. Convergence insufficiency: incidence,
diagnosis and treatment. J Am Optom Assoc. 1978;49:673-680.
- Cooper J, Medow N. Intermittent exotropia of the divergence excess
type: basic and divergence excess type (major review). Bin Vis Eye Mus Surg
- Cooper J, Scheiman M. American Optometric Association Clinical
Practice Guideline. Care of the subject with accommodative and vergence
dysfunction. 2nd ed. St. Louis, Mo.:American Optometric Association, 1998.
- Gur S, Ron S. Does work with visual display units impair visual
activities after work? Doc Ophthalmol. 1992;79:253-259.
- Rouse MW, Borsting EJ, Mitchell GL, et al. Validity and reliability
of the revised convergence insufficiency symptom survey in adults.
Ophthalmic Physiol Opt. 2004;24:384-390.
- Scheiman M, Cotter S, Rouse M, et al. Randomised clinical trial of
the effectiveness of base-in prism reading glasses versus placebo reading
glasses for symptomatic convergence insufficiency in children. Br J
- Scheiman MM, Hertle RW, Beck RW, et al. Randomized trial of
treatment of amblyopia in children aged 7 to 17 years. Arch Ophthal.
- Scheiman M, Mitchell GL, Cotter S, et al. A randomized clinical
trial of vision therapy/orthoptics versus pencil pushups for the treatment of
convergence insufficiency in young adults. Optom Vis Sci.
- Sheedy J, Parsons S. The video display terminal eye clinic:
clinical report. Optom Vis Sci. 1990:67:622-666.
- Scheiman M, Mitchell GL, Cotter S, et al. A randomized clinical
trial of treatments for convergence insufficiency in children. Arch
- Sheedy JE, Hayes JN, Engle J. Is all asthenopia the same? Optom
Vis Sci. 2003;80:732-739.