PERIPHERAL DEFOCUS INDUCED BY «PERIFOCAL-M» SPECTACLES AND MYOPIA
PROGRESSION IN CHILDREN
¹ The Helmholtz Moscow
Research Institute of Eye Diseases, 105062, Moscow, Russia;
² Vision Center
"ArtOptika" 117461, Moscow, Russia
has significant role in developing of refraction. «Perifocal - М» spectacle lens provides
different correction in central and peripheral refraction of the eye in
Purpose. To examine influence
of «Perifocal - М» spectacles on wavefront
aberrations, peripheral refraction and myopia development in children. Materials
and methods. Prospective parallel cohort open clinical study was contributed,
with 75 children involved, children aged from 9 to 14 with progressive myopia
from -1,0 to -6,0 D. Trial period was 6-18 months. Patients was randomly selected
to wear «Perifocal - М» or monofocal spectacles. Results and
discussion. «Perifocal – M» spectacles create relative peripheral myopic
defocus or significantly decreases peripheral hyperopic defocus, and induces positive
spherical aberrations, in turn monofocal spectacles creates negative. After 6 months
of using «Perifocal - М» spectacles noticed less axial growth by 0,05 mm, less
myopic shift: manifest refraction – by 0,19D, cycloplegic refraction by 0,11D
comparing to control group. After 12-18 months of using «Perifocal - М»spectacles noticed less axial growth by 0,07mm, less
myopic shift: manifest refraction – by 0,3D, cycloplegic by 0,27D. There no cases
of heteroforia decompensation during using «Perifocal - М»spectacles. Conclusion. «Perifocal – M» spectacles
contribute to slow myopia progression comparing to control group.
In recent years, peripheral defocus has played a significant role in the
formation of refraction. The latter
refers to the relative weakening or strengthening of ray’s refraction during
the transition from the center of the fovea to the peripheral parts of the
retina. In the first case, talk about the relative peripheral hypermetropia, or
hyperopic defocus, in the second of myopic peripheral defocus. In a number of
experimental studies have shown that hyperopic defocus in the periphery of the
retina stimulates the growth of the eye and the formation of axial myopia, and
myopic on the contrary, inhibits the refractogenesis [1,2]. The results of
clinical studies also indicate a stimulating eye lengthening role of hyperopic
defocus , the connection of myopia with peripheral hypermetropia .
A lot of work is devoted to the study of peripheral refraction in various
types of correction. It is reported that traditional single vision spectacles
increase peripheral hyperopic defocus compared to uncorrected myopic eyes ;
that traditional spherical contact lenses create myopic defocus on the
periphery, unlike spectacles ; that these lenses, on the contrary, form
hyperopic defocus, and relative myopia on the periphery creates multifocal
contact lenses .
Interest in the
study of peripheral refraction in recent years is supported by the results of
clinical observations of children using orthokeratological contact lenses. It
is here that the inhibition of myopia progression and axial length growth
observed by all can be most associated with a significant permanent induced
myopic peripheral defocus [8.9]. This effect is provided by changing the
topography of the cornea under the action of OK lenses. The central part of the
cornea is flattened, and the paracentral and peripheral becomes "steeper"
and more refracted. This leads to the formation of a positive spherical
aberration and, due to a stronger peripheral refraction, a relative myopic
defocus on the periphery.
By analogy with multifocal
contact lens and orthokeratology, there is a development of special spectacle lens
design  or designed to create a relative myopia at the periphery .
Few years ago, such
lenses were created and introduced on Russian market. «Perifocal - М» spectacles have special
design with progression of refraction (addition) both sides from optical center
in horizontal, stable refraction in geometric center, refraction along vertical
meridian is similar to central refraction in geometric center. «Perifocal - М» lens allow to correct
differently central and peripheral refraction of the eye in horizontal meridian.
Physical and mathematical calculations in the "Perifocal-M"
optical surface design modeling carried out by a leading expert in the field of
optical surface design - Professor of the University of Madrid Jose Alonso
(University Complutense of Madrid, Madrid, Spain). The unique properties of the
"Perifocal-M" lens make it possible for the first time in practice to
identify the effectiveness of different correction of nasal and temporal
relative peripheral hyperopia to control the progression of myopia in children.
Purpose. To study the effect of «Perifocal - М» spectacles on wavefront
aberrations, peripheral refraction and myopia development in children.
methods. A clinical prospective parallel open-label study was
conducted in 75 children aged 9-14 years with progressive myopia from -1.0D to
-6.0D and astigmatism of not more than 1.0D, requiring no optical correction,
with the best corrected visual acuity of 0.8 or more, binocular character of
vision. The follow-up period was 6-18 months. Patients of the main group (60
children) were assigned "Perifocal - M" spectacles for permanent using.
Patients in the control group wore monofocal spectacles. Correction was weaker by
0.5D than objectively identified cycloplegic refraction.
Examination of all children was carried out before spectacles prescription,
6 months and 12-18 months after the start of using spectacles. The examination
included: visometry without correction and with the best subjective correction,
determining the nature of vision, autorefractometry before and after
cycloplegia (cyclomed 1% - 2 times), biomicroscopy, ophthalmoscopy,
accommodation study (determination of relative accommodation reserves,
objective accommodation response measured by open field autorefractometer Grand
Seiko WR-5100K, absolute accommodation), muscle balance study (Forias) , study
of the ratio of accommodation convergence and accommodation (AC/a) gradient
method by Von Noorden, an objective study of peripheral refraction at 15° and
30° in the nasal (N15 and N30) and temporal (T15 and T30) meridian without
correction and in new spectacles using the open-field autorefkeratometer Grand
Seiko WR-5100K (Japan), ultrasonic echobiometry - A/B Scan System Model 837 of
the company "Allergan Humphrey" (USA); the aberrometry – ОРDScan (Nidek,
M" spectacles was prescribed for constant using. All patients adapted to
the lenses easily. Terms and ease of adaptation did not differ from the
adaptation to any new spectacles. The maximum period of adaptation was 7 days. There
was not any single case of refusal to use "Perifocal-M" spectacles, associated
with difficult adaptation.
Influence of «Perifocal-M»
spectacles on peripheral refraction of the eye.
M" spectacles form myopic or reduce hyperopic relative peripheral defocus
in myopic eyes. The results of the peripheral refraction study of lenses
"Perifocal-M", obtained by Grand Seiko WR – 5100K without correction
and using spectacles "Perifocal – M", showed that without correction
hyperopic defocus occurs: in 61.5% of eyes in T15° and T30°; in 46% of eyes in
N15°; in 100% of eyes in N30°. Without correction hyperopic defocus averaged: +
0.11±0.11D in T15° and + 0.72±0.28D in T30°; +0,02±0,1D in N15° and +1,53±0,2D
Myopic defocus was
formed in "Perifocal – M" spectacles in the zone of 15°, which
averaged -0.03±0.1D in T15° and -0.35±0.16D in N15°. In the area of 30°
hyperopic defocus was decreased on average by 0.1±0,35D at T30° and 0.34±0,07D
to N30° (Fig. 1).
with lenses of special design with horizontal progression
"Perifocal-M" form a relative peripheral myopic defocus in the eye or
significantly reduce peripheral hyperopic defocus.
«Perifocal-M» spectacles on aberrations of the eye.
In our study,
according to aberrometry without correction in 50% of the examined eyes with
myopia, spherical aberration of the highest order had a negative sign. Negative
spherical aberration plays an unfavorable role in the progression of myopia,
because it creates hyperopic peripheral defocus. The mean value of higher-order
spherical aberration in the examined group was positive and amounted to
monofocal spectacles showed an increase of negative spherical aberration. It
was found in 75% of the eyes and its average value was -0.06±0.01 µm
(p<0.01). Along with the natural, by reducing defocus, reducing the overall
level of aberrations (Total RMS) from 4.19±0.5 µm without correction to 2.9±0.2
µm in monofocal glasses (p<0.05), there was a tendency to increase higher –
order aberrations (RMS-HO) from 0.282±0.03 µm to 0.36±0.04 µm in the correction
of myopia with monofocal glasses (p>0.05).
- M" spectacles due to a more complete correction of central refraction,
the decrease in the overall level of aberrations was even more pronounced than
in monofocal spectacles. Its value in "Perifocal - M" spectacles was
1.66±0.3 microns compared to 4.19± 0.5 before correction (p<0.01). Low-order
spherical aberration tended to increase from 0.35±0.05 µm to 0.42±0.1 µm
(p>0.05). Coma and trefoil increased significantly: from 0.15±0.02 µm to
0.23±0.09 µm and from 0.17±0.02 µm to 0.27±0.09 µm, respectively (p>0.05).
aberration of the highest order in the eyes, where it had a negative value
without correction, decreased or even turned into a positive one. The mean
value of spherical aberration (NO-sph) was 0.022±0.04 µm, that is, there was a
tendency to increase the positive spherical aberration by 7 times compared to
non-corrected eyes (p>0.05), the difference is unreliable. As already noted,
positive spherical aberration forms myopic peripheral defocus, which plays a
crucial role in inhibiting the progression of myopia. The main purpose of
"Perifocal-M" spectacles is the formation of such a defocus due to
the special design of this lens. Studies have confirmed the achievement of this
goal: "Perifocal" spectacles induce positive spherical aberration,
while monofocal spectacle lenses form a negative (table.1).
«Perifocal-M» spectacles on refraction and axial growth dynamics
The dynamics of central
refraction and AL values were monitored in 60 patients who used "Perifocal
- M" spectacles for 6 months, in 51 patients for 12-18 months (table. 2,3).
The dynamics of refraction in all patients of the control group was monitored
during 12-18 months with intermediate control at 6 months.
subjective refraction after 6 months of "Perifocal - M" spectacles using increased
by an average of 0.09±0.04D (varied from 0 to -1.0D), after 12-18 months
increased by 0.28±0.04D (changed from 0 to -1.5D). The myopic shift of the
subjective refraction was significantly lower than in the control group. In the
control group, manifest subjective refraction increased by an average of
0.23±0.04D after 6 months, and by 0.55± 0.03D after 12-18 months (p<0.01).
refraction measured by
autorefractometry, after 6 months increased on average by 0.15±0,04D, 12-18
months 0.28±0,04 diopters. In the control group, manifest objective refraction
increased by an average of 0.25±0.04D after 6 months and 0.55±0.03D after 12-18
months. The difference between the main and control groups was significant for
each observation period (p<0.01).
objective refraction after 6 months of using "Perifocal - M" spectacles changed
from +0.25D to -1,25D. The average shift of cycloplegic objective refraction
was +0.02±0.01D. Stabilization of cycloplegic refraction was observed in 16.7%
of cases (20 eyes), weakening of cycloplegic refraction was observed in 40% of
cases (48 eyes), in 41.6% of cases (50 eyes) manifest refraction increased by
0.25-0.75D (average -0.29±0.04D), one child (1.7%) had bilateral enhancement of
cycloplegic refraction by -1.25 D.
After 12-18 months
of "Perifocal - M" using cycloplegic objective refraction increased
by an average of -0.28±0.04D. Stabilization of cycloplegic refraction was
observed in 39.2% of cases (40 eyes), the weakening of cycloplegic refraction
was observed in 9.8% of cases (10 eyes), in 51% of cases (52 eyes) cycloplegic
refraction increased by an average of -0.4±0.03D.
The myopic shift
of the objective cycloplegic refraction was significantly lower in children who
used "Perifocal M" spectacles, than in the control group. In the control group, cycloplegic objective
refraction after 6 months increased by an average of -0.13±0.04 D (p<0.01) after 12-18
months at -0.55±0.03D (p<0.01).
The axial length
value after 6 months of "Perifocal-M"
spectacles using increased by an average of 0.03±0.02mm, after 1 year by
0.08±0.02mm. in the control group, the axial length growth was twice as much:
after 6 months, AL increased by 0.08±0.02mm, after 12-18-by 0.15±0.03mm (table.
3). The difference was significant for each observation period (p<0.05).
«Perifocal-M» spectacles on visual acuity, accommodation, phoria.
M" spectacles spherical component were prescribed 0.5D less than
objectively identified cycloplegic refraction. In the appointment of such a
correction binocular visual acuity in "Perifocal-M" spectacles ranged
from 0.9 to 1.0 and averaged 0.95±0.04.
acuity in "Perifocal-M"
spectacles after 6 months remained consistently high and averaged 0.94±0.04.
After 12-18 months binocular visual acuity in "Perifocal – M" spectacles
In the control
group, binocular visual acuity in spectacles at the beginning of the study was
0.88±0.04, after 6 months - 0.78±0.04, after 12-18 months – 0.67±0.04.
Reserves after 6 months of "Perifocal-M" spectacles
using increased by an average of 0.3 ±0.04D, after 12-18 months RAR increased
by 0.4±0.04D from baseline (p>0.05).
In control group RAR
has not changed.
volume after 6 months of "Perifocal-M"
spectacles using increased by an average of 2.27±0.16D, after 12-18 months-by
3.0±0.18D compared with the baseline value and 27.5% (33 eyes) reached the age
In the control
group, the absolute accommodation volume increased by 1.0±0.12D and 1.4±0.13D
compared with the initial values, respectively, and at the end of the
observation reached the age norm in 2 cases. The increase in the values of
absolute accommodation volume to groups of children who wore glasses "Perifocal
– M" in comparison with the control group was reliable for each of
observation periods (p<0.01).
accommodation response after 6 months of
"Perifocal-M" spectacles using increased
slightly, on average by 0.1±0.04D, after 1 year-by 0.3±0.04D (p>0.05).
In the control
group, the objective accommodation response has not changed. The difference in
the value of the objective accommodation response in the main and control
groups was unreliable.
The tone of
after 6 months "Perifocal – M" spectacles using has changed slightly:
increased by an average of 0.03±0.02 D, and the tone of accommodation of the
open field-0.08±0.03D. After 12-18 months, the tone of accommodation remained
within the reference values, the tone of accommodation in the open field has
changed - have decreased on 0,1±0,03D from baseline. According to E. P. Tarutta
and N. A. Tarasova decrease in accommodation tone is a favorable prognostic
sign and is associated with a decrease in the rate of further myopia
In the control
group, after 6 months, the tone increased by 0.03±0.02D, the open field tone by
Phorias. In the main and
control groups were included only subjects with physiological values of
heterophoria for near. After 6 months and 1 year from the beginning of using
"Perifocal-M" spectacles in any case, the values of phoria did not go
beyond physiological. This distinguishes the "Perifocal – M" spectacles
from the usual progressive spectacles, using which it is possible to form a
decompensated exophoria for near and far, and in particularly severe cases –
There were no
cases of decompensated phoria during the observation period in the control
AC/A. The AC/A ratio is slightly decreased on average by 0.2 prism.D/D,
presumably at the expense of some increase in accommodative ability of the eye,
however, this change was not reliable.
1. «Perifocal - М» spectacles can be
used in children for permanent using, adaptation goes easy.
«Perifocal – M» spectacles create myopic or decrease hyperopic peripheral
defocus in myopic eyes. «Perifocal-М» spectacles induce
positive spherical aberration in the eye, while monofocal spectacles form
3. «Perifocal – M»
spectacles contribute to relative refraction stabilization in myopia comparing
to control group. The most significant difference with the control group in first
6 months of observation.
Binocular visual acuity
when using the same «Perifocal – M» spectacles stay high during 12-18 months.
«Perifocal – M» spectacles
have obvious advantages over usual progressive spectacles, because there is no
decompensated exophoria during it’s using, which may be noticed with
Smith E.L. 3rd, Kee C.S., Ramamirtham R.,
Qiao-Grider Y., Hung L.F. Peripheral vision can influence eye growth and
refractive development in infant monkeys. Invest Ophthalmol. Vis. Sci. 2005;
Smith E.L. 3rd, Huang J., Hung L.F., Blasdel
T.L., Humbird T.L. , Bockhorst K.H. Hemiretinal form deprivation: evidence for
local control of eye growth and refractive development in infant monkeys.
Invest. Ophthalmol. Vis. Sci. 2009; 50: 5057–69.
Hoogerheide J., Rempt F., Hoogenboom W.P.
Acquired myopia in young pilots. Ophthalmologica. 1971; 163: 209–15
Mutti D.O., Hayes J.R., Mitchell G.L., Jones
L.A., Moeschberger M.L., Cotter S.A., Kleinstein R.N., Manny R.E., Twelker
J.D., Zadnik K. Refractive error, axial length, and relative peripheral
refractive error before and after the onset of myopia. The CLEERE Study Group.
Invest. Ophthalmol. Vis. Sci. 2007; 48: 2510–19.
Lin Z., Martinez A., Chen X., Li L., Sunkaridurq
P., Holden B.A., Ge J. Peripheral defocus with single-vision spectacle lenses
in myopic children. Optom. Vis. Sci. 2010; 87: 4–9.
Backhouse S., Fox S., Ibrahim B., Phillips J.R.
Peripheral refraction in myopia corrected with spectacles versus contact
lenses. Ophthalmic. Physiol. Opt. 2012; 32: 294-303.
Kang P., Fan Y.,
Oh K., Trac K., Zhang F., Swarbrick H. A. The effect of multifocal soft contact
lenses on peripheral refraction. Optom.Vis. Sci. 2013; 90: 658-66.
Tarutta E. P., Verzhanskaya T. Ju.. Possible
mechanisms of orthokeratologycal contact lenses inhibiting impact on myopia
progression. Rossijskij oftal'mologicheskij zhurnal. 2008; 1 (2): 26-30.
Kang P., Swarbrick Н. Peripheral
refraction in myopic children wearing orthokeratology and gas-permeable lensesт. Optom.Vis.
Sci. 2011; 88: 476-82.
Sankaridurg P., Donovan L., Varnas S., Ho A., Chen X., Martinez A.,
Fisher S., Lin Z., Smith E.L., 3rd, Ge J., Holden B. Spectacle lenses designed
to reduce progression of myopia: 12-month results. Optom. Vis. Sci. 2010; 87:
D.A., Mathur A., Varnas S.R. Visual performance with lenses correcting
peripheral refractive errors. Optom. Vis. Sci. 2013; 90:1304-11
E. P., Tarasova N.A. Tone of accommodation in myopia and its possible
prognostic significance. Vestnik oftal'mologii, 2012; 2: 34-7
E. P., Tarasova N.A. Comparative efficiency evaluation of subjective and
objective methods of ADD power selection in prescribing progressive lenses to
optometrija.2011; 9: 40-4.