Download Creative optometry: On the use of multifocal contact lens for non

CONTACT LENS GRAND ROUND: On the use of multifocal contact lens for nonpresbyopic patients.
Introduction
The use of multifocal lenses is mainly devoted to the correction of presbyopic patients.
However, younger patients with binocular function deficiency could benefit from the use of
more convex power at near. This could be the case of patients suffering from convergence
insufficiency, true lack of accommodation or with convergence-accommodation balance
deficiency (high AC/A ratio).
The following case illustrates another way to use multifocal contact lenses in a regular
contact lens practice. In this specific case, a monocular fit was tried with success to
compensate unilateral latent hyperopia creating an anisometropia of +4 D.
SUBJECTIVE
CB is a Caucasian female of 32 y.o. who was seen for the first time in August 2007 for her
general examination at Clinique Universitaire de la Vision. Her chief complaint at that time
was a reduced vision at night, especially under driving conditions. She was wearing, on a part
time basis, a pair of glasses of OD plano and OS +2,00. Her prescription did not vary in the
last ten years. She was not wearing contact lenses. She is a secretary employed at U de
Montréal and was doing computer work for 8 hours/day. She did not experience ocular
fatigue at near, except from time to time. At this moment, she relies on the use of her glasses
to remove with success that symptom.
Family ocular history revealed that one of her sister was penalized by amblyopia of the left
eye. She did not know the level of her visual acuity on that side. No other significant findings
were noted.
OBJECTIVE
Preliminary tests, with glasses on, revealed the presence of 3 degrees of fusion with full
binocularity. Ocular movements were full in all gazes with no restriction.
Refractive findings were OD plan and OS +2,00 for 6/6 visual acuity on each side. Ocular
health was evaluated within normal limits either for the anterior segment than for the
posterior segment. Peripheral visual fields were complete with no scotoma and intraocular
pressure was measured as 9 mm Hg o.u. for a corneal thickness of 560 um.
ASSESSMENT
Diagnosis of hyperopia and anisometropia was made by the clinician at this time.
PLAN
The patient was told to wear her visual correction most of the time, especially at near
distance and to alleviate ocular fatigue at night.
CONTACT LENS FITTING VISIT
The patient went back in October 2007, since she was looking to be fitted in contact lenses.
She did not enjoy to wear her glasses on a full time basis.
Topographic maps was taken and no abnormality was found. A regular symmetrical lowastigmatic pattern gave Sim K values for the left eye of 42,00 x 43,00 @ 98 with E values of
0,40 @98 and 0,96 @ 8.
In order to do not compromise corneal health, silicone hydrogel lens Focus Night & Day
was tried and fitted on the left eye (BC 8,4, +2,00). Visual acuity was 6/6 and the patient felt
comfortable. Hydrogen peroxide care system (Clear Care, Ciba Vision) was provided to the
patient. The patient was instructed to wear the contact lenses for 6 h00 the first day,
increasing by 2h00/day up to 14h00 of maximal wear. A follow-up exam was planned 3
weeks later.
FOLLOW-UPS
At this time the patient reported discomfort at the end of the day with dryness and mucous
secretions. She also reported hat she noticed an improvement in her vision, at near and at
far, in the first 2 weeks, even for night driving. However, in the last week, she reported some
ocular fatigue symptoms as if she had no lens on her left eye.
Entering v.a. at the follow-up visit was 6/6 but objective retinoscopic over-refraction gave
+1,25. Subjective over-refraction was +0,75. Patient was therefore advised to come back for
a full cycloplegic refraction in order to assess the amount of left hyperopia.
In November 2007, cycloplegic refraction leaded to the following findings: OD +0,75 6/6
and OS +4,00 -0,50 x 90 6/6.
Spherical contact lens of +3,50 was tried on the left eye. Silicone hydrogel Pure Vision
(Bausch & Lomb) was selected with a base curve of 8,6 since its anterior aspheric surface
provides a better correction of spherical aberrations especially disturbing in night driving
conditions. Patient felt comfortable with the lens but the vision, post-cycloplegia, was not
truly balanced. She seemed to be more comfortable if the right eye was also corrected with a
+0,50 contact lens. Patient was therefore fitted accordingly with Pure Vision spherical
contact lenses on both side.
Two weeks later, the patient went back and reported that she was not comfortable with two
lenses on, complaining of a hazy vision at all time, and at all distances. She felt more
comfortable without the right lens on and she had decided to do not wear it. The left lens
was more comfortable compared with the previous one but still she felt an unbalanced
vision especially at far and while driving.
Objective over-refraction of the left eye gave +0,50 -0,75 x 90 result but subjective overrefraction gave -1,25 D for 6/6 balanced and comfortable vision. Ocular health remained
good without hyperemia nor adverse signs related to contact lens wear. Cornea was clear
without staining.
It was pretty obvious that hyperopia was well corrected but, as it is the case most of the
time, the full correction of this ametropia was not subjectively accepted. Options are limited
since the use of single vision contact lens of +2,00 up to +2,50 was initially tried without
success.
We then decided to try a multifocal lens in order to let the eye to decompensate at least at
near, which could be easier. Since the patient was mostly working at near distance, binocular
vision would be favoured by the use of a multifocal lens. Pure Vision Multifocal lens was
selected considering oxygen permeability for hyperopic corrections. This silicone hydrogel
offers a near-centered design really effective without disturbing the distance vision.
We selected a +2,50 lens for distance and the low add power for near (+1,50) . Intermediate
vision for computer use was covered by the progression of the power within the lens. Upon
insertion the patient felt immediately more comfortable either for the lens itself than for the
vision. Clear Care regimen was kept and the patient was asked to wear her lens for a full
month.
The last follow-up visit was made at the beginning of December 2007. Patient was really
happy with the contact lens we fitted on her. She was able to see well at far and at near
without headache, disturbance, nausea or all other signs or symptoms related to unbalanced
vision.
Visual acuity was measured, for o.s., at 6/7,5 at distance, improvable by over-refraction of
+0,50 to 6/6 +2. We tried +3,00 low add lens and the patient remained comfortable at all
distances. The right eye was left uncorrected.
Since we were close of the cycloplegic refraction, we decided to remain at this level for the
moment and let the patient go with this prescription. She called back 10 days later
confirming that the vision was still comfortable at all distance. Therefore, a supply of 6
months of lenses was ordered for the patient. A follow-up exam was planned at this time
before the prescription renewal, mainly in order to check the prescription accuracy.
CONCLUSION
Hyperopia is a difficult ametropia to manage especially in older patients. This case illustrates
the importance to conduct cycloplegic refraction in every single patient that shows
anisometropia or that has symptoms of eye fatigue. In the optometric world, cycloplegia is
mostly reserved for the examination of children or younger patients but anyone who comanaged refractive surgery patients can make testify about the benefits to conduct
cycloplegic refraction when comes the time to accurately estimate the ametropic value of a
patient.
A second lesson from that case reminds us that binocularity is the basis of optometric
science. Contact lenses, through creative fitting, can help practitioners to achieve their goal
of restoring full binocular function when it is needed and represents surely a valuable tool in
our hands to respect our primary mission as optometrists.