Mechanisms of Perifocal-M Therapeutic Impact and Long-Term Data in Children with Progressive Myopia
OV¹*, Tarutta EP¹ and Ibatulin RA²
Helmholtz Moscow Research Institute of Eye Diseases, Moscow, Russia
Center “ArtOptika”, Moscow, Russia
Proskurina OV., et al. “Mechanisms of Perifocal-M Therapeutic Impact and
Long-Term Data in Children with Progressive Myopia”.
Ophthalmology 10.11 (2019): 63-69.
Author: Proskurina OV, The Helmholtz Moscow Research Institute of Eye Diseases,
August 14, 2019; Published: October 18, 2019
discusses in detail the multifactorial mechanisms of the impact of spectacles
with perifocal defocus on progression of myopia in children. Impact on local
retinal mechanisms of neuroregulatory control of eye growth currently most
effective in preventing the development and progression of myopia. Optical
correction of peripheral hyperopia with the formation of peripheral myopic defocus
affects the manifestation of a biochemical cascade from the retina to the
choroid and to the sclera, which inhibits the eye growth. Optical methods of
controlling myopia, including spectacles, are widely used in local and foreign
ophthalmic practice. Since 2011 spectacles with Perifocal-M lenses have been
used in Russia, providing greater impact functionality on myopic eyes in
comparison with foreign counterparts. The design features of such spectacle
lenses have a complex effect on various optical and physiological structures of
the eye, each of which contributes to refractogenesis. Perifocal spectacles
take into account the characteristics of the central and peripheral refraction
characteristic of the myopic eye along the horizontal and vertical meridians.
They have stronger horizontal refraction, which allows to eliminate the optical
imbalance, specific for myopic eye and creates an emmetropic optical profile.
Construction of perifocal spectacle lenses allows you to correct relative
peripheral hyperopia, to create myopic defocus in the horizontal meridian,
affect the ratio of refractive indices of the nasal and temporal halves of the
retina. This is due to an earlier onset and more pronounced optical effect on
the nasal half of the retina relative to temporal. Spectacles with perifocal
defocus induce positive spherical aberration in the eye, increase the
accommodative ability of the eye, help maintain high binocular visual acuity, improve
binocular interaction during near-work, impede the development of heterophoria.
Optical features of Perifocal-M spectacles create conditions for versatile
functional effects on various structures of the eye, which leads to deterrence
the process of myopia progression.
International myopic conference, once again, was noticed, that revealed by Josh
Wallman  local retinal mechanisms of neuroregulatory management of eye
growth in model experiments in animals, at present day proved in human and
methods to affect said mechanisms is the most effective to prevent myopia
progression . Optical correction of relative peripheral hyperopia with
creation of peripheral myopic defocus, provokes biochemical cascade from retina
to choroid and to sclera, which holding the eye growth. Treatment of
progressive myopia by creation of peripheral myopic defocus, also popular in
Russian ophthalmologic practice using both: contact methods and spectacles.
possibilities of optical production, in particular, free form technology, lets
us to create new designs of optical surfaces with non-axial symmetric shapes,
that was beginning of new spectacle lens occurrence, which provides different
correction of axial and non-axial refraction to control myopia. At present day
there are three lenses of this type in international optometric practice. Since
2011, mainly in South-East Asia,
widely used lenses with radial progression called Myovision, one of inventors
of this lens was famous Australian scientist Brien Holden. Construction feature
of said lens is central aperture of stable refraction with 20mm diameter with
additional positive refraction of 1,9D on periphery in 25mm from optical
center. Construction is asymmetric for right and left eyes. According study
results conducted in 2009, which involved 210 children, it was found, that in
treatment group by refraction and axial length data progression of myopia was
30% less comparing to control group . Authors noticed, that the most effect
of myopia control by Myovision spectacles was in children of myopic parents.
September of 2017 at the International myopia conference in plenary section,
dedicated to optical methods of myopia control, was presented clinical study
results of using Multi segment lenses in children with progressive myopia. Lens
created in association with Hong Kong polytechnic university. Construction
features are in original way to create fast progression from 10mm central zone
border by multiple micro segments with 1,5mm diameter, each of segment has
additional refraction of 3,5D. According two-years randomize clinical study
results, which involved 160 children, divided to treatment (79 children) and
control(81 children) groups, noticed, that children used Multi segment lenses
had 59% less progression (p < 0,0001) by autorefractor data and 60% less(p
< 0,0001) by axial length comparing to control group used monofocal lenses
the same time with MyoVision lens optometrists start to use Perifocal lens in
their practice, it was designed by famous specialist in the field of spectacle
lenses design modeling professor Jose Alonso (University Complutense of
Madrid). Features of Perifocal lens optical design providing wider functionality
for influence on myopic eye comparing to lens said before. Optical construction
of Perifocal lens provides stable refraction in geometric center and asymmetric
progression of refraction to the both sides in horizontal plane passing through
geometric center. Refraction progression for each side has asymmetric start point
from geometric center. Refraction along vertical meridian is almost equal to
refraction in geometric center. Lens has it’s nasal and temporal sides relative
to lens position in front of the eye. Addition in nasal side starts from 5,5 mm
and in temporal- 3,5 mm from geometric center and reaches its maximum value of
2,5D at nasal side and 3,0D at temporal at 24 mm from geometric center. Since
2011, many comprehensive studies have shown that the optical design of the lens
Perifocal creates conditions for the impact on various etiopathogenetic factors
spectacle lenses consider the characteristics of the central and peripheral
refraction along the horizontal and vertical meridians in the myopic eye: The
known features of the ellipsoid shape of the myopic eye, in contrast to the
spherical shape of the emmetropic eye, create an optical imbalance in it, where
along the vertical Meridian there is mainly a relative peripheral myopia and
the relative peripheral hyperopia is determined horizontally [5,6]. According
to the given justifications of J. Wall man in his famous scientific hypothesis,
the myopic eye receives conflicting signals along the vertical and horizontal
meridians, the eye will grow along the axis until the myopic Central part of the
retina balances the relatively hyperopic periphery, ignoring the relative
peripheral myopia along the vertical meridian . Functional – morphological
features of the retinal topography also show the importance of the relative
peripheral hyperopia correction in the horizontal meridian. Thus, the density
of cones and ganglion cells decreases more rapidly to the periphery along the vertical
meridian, in contrast to the horizontal, which reflects the potentially
dominant effect of visual signals from the retina horizontally relative to the
vertical field of view [7,8]. The Perifocal lens has a stronger horizontal
refraction, which when correcting the myopic eye allows to eliminate the
characteristic optical imbalance and thereby create an emmetropic optical
profile in the myopic eye.
spectacles correct relative peripheral hyperopia and create myopic defocus in
the horizontal meridian: Relative peripheral hyperopia characteristic for the
myopic eye in the horizontal meridian contributes to the disturbance of local
of studies show that hyperopic defocus with respect to the retina causes
thinning of the vascular and lengthening of the eyeball, in turn, myopic
defocus causes thickening of the vascular and a decrease in the axial length of
the eye . Clinical studies have shown that the design features of the
Perifocal lenses correcting relative peripheral hyperopia or create myopic
defocus  that provides the conditions for influence on local
neuro-regulatory mechanisms of eye growth control.
spectacles affects the ratio between nasal and temporal halves refraction:
Off-axis refraction studies in the period of progression of myopia have shown
that the ratio of the refraction values of the nasal and temporal parts in most
cases asymmetrically, this fact is noted in numerous works, starting with the
first descriptions of the state of peripheral refraction in myopia . In one
of the last publications, which resulted in 24 months a clinical study of the
dynamics of peripheral refraction in 1531 myopic children under the age of 13
revealed that a large nasal-temporal asymmetry in 30 degrees peripheral
refraction at baseline was associated with lower levels of myopia progression
in the future . According to the authors, these data can help in predicting
and controlling the progression of myopia. In earlier studies, it was noted
that in the process of myopia progression, according to off-axis refraction and
off-axis biometrics, refraction of the nasal half of the eye increases more
than the temporal one [13,14]. In more myopic eyes, in cases of anisomyopia, a stronger
off - axis refraction in the nasal half of the eye relative to the temporal one
was also revealed . The author believes that in the development of
potential treatments to fight against myopia, it is important to understand the
origin of this shift. In model experiments on primates in inducing myopia by
means of two zone contact lenses forming a peripheral hyperopic defocus, the
development of myopia with nasal-temporal asymmetry of refraction and a larger
increasing in its temporal half of the eye was noted . The author links the
increasing of nasal-temporal asymmetry of peripheral refraction with growth and
considers that the resulting asymmetry is a compensatory manifestation of axial
off-axis refraction study in emmetropes revealed nasal-temporal asymmetry with
stronger refraction in the temporal half , which is also more typical for
eyes with stable myopia, in contrast to the eyes at the beginning of
progression . According to other authors, detection of more myopic
refraction in the nasal half, unlike temporal, can be a predictor of myopia in
not yet myopic children .
design features of the Perifocal lens, which provides an earlier start and
stronger optical effect on the nasal half of the retina relative to the
temporal, are justified. In 2014, a retrospective analysis of refractometric
data of 46 children aged 7 - 12 years with myopia from -1.0D to 3.75D was
carried out in the ArtOptica center, which shows that wearing Perifocal
spectacles for 12 months decreased axial refraction or no progression of
myopia. The analysis of the refractometric data before and after wearing
Perifocal was carried out by the Fourier converting of the spherical-cylindric
component into interrelated vectors in order to reduce the measurement error
caused by oblique incidence astigmatism, taking into account the research data
indicating that the retina determines the defocus sign along the sagittal focal
plane . Available literature data also indicate that changes in the values
of sagittal focus correlate with changes in off-axis biometrics at this point
to the data obtained in table 1, we noted that in cases of axial refraction
reduction or stopping the progression of myopia, there is an increase in
peripheral refraction in the temporal half of the eye with its weakening in the
nasal part. The results of this study may indicate that Perifocal spectacles
creates conditions for changing the ratio of peripheral refractive power
between the nasal and temporal halves of the eye, which has a deterrent effect
on the progression of myopia.
spectacles increases the accommodation ability of the eye (relative accommodation
reserves, absolute accommodation volume): Reduced accommodation functions of
the eye continue to be among the likely drivers of myopia. There is no common
understanding of the causes of accommodation disorders in myopia, the primary
factor or accompanying process. The results of studies of geneticists published
recently identified an intriguing dilemma-an increase in the threshold of
retinal sensitivity to the degree of the spot blurring is the main reason for
reducing the rate of adaptive response of accommodation  or the
morpho-functional state of the ciliary muscle is the primary cause of
accommodation disorders in myopia . In turn, many years in wide clinical
practice the optical-reflex trainings normalizing and improving an
accommodation condition are used [23-26]. At the heart of these methodologies
are different ways of micro blurring the image with the objective response of
accommodation. The optical design of the Perifocal lens creates the conditions for
accommodation training. Progression of refraction in one and opposite
directions horizontally relative to optical center of the Perifocal lens
provides conditions when arbitrary and non-arbitrary versional eye movements
occur in horizontal contact with the optic axis in the field of hypocorrection
that is the stimulus for the accommodative response according to the type of
relaxation of the ciliary muscle. Thus, the alternation of vision through a
stronger and weaker correction, creates the conditions for the exercise of accommodation.
spectacles helps to eliminate the stimuli to accommodation from the
extra-foveal retina during near work: According to the literature [27,28], the
contour of the retina in myopic eyes in accommodation during near work is not
altered or even strive to be steeper, it respectively, maintains or increases
the relative peripheral hyperopia. In turn, in the emmetropic eye during
accommodation while doing near work, on the contrary, the retinal contour
changes markedly due to increased off-axis refraction [28-30]. Thus, the
preservation of relative peripheral hyperopia in the myopic eye in the
horizontal meridian at near work is an incentive to accommodation, creating
conditions for excessive tension. According to the literature, the stimulus to
accommodation response from the retinal periphery in the region up to 30
degrees from fovea may be 1 - 2D . Perifocal lens corrects peripheral
hyperopic defocus and help to eliminate not physiological stimulus to the
response of accommodation from extra-foveal image focus.
spectacles induces positive spherical aberrations in the eye: We know from
literature [32,33] that physiologically the sign of the spherical aberrations
of the eye in children varies with age. Thus, during the distance fixation in
children up to 6 years, negative spherical aberrations prevail. After 6 - 7
years and throughout life, only positive spherical aberration prevails in the
eye, when fixing into the distance. Studies have shown that positive spherical
aberrations have a physiological effect on the eye, inhibiting eye growth and minimizing
the tendency to myopia [34,35]. The Perifocal lens, due to the progression of
horizontal refraction, provides conditions for stronger refraction of the rays
going into the eye in the area of the pupil edge, which creates positive
spherical aberrations in the eye .
studies have shown that the correction of myopia with a monofocal lens creates
negative spherical aberrations in the eye that can stimulate the axial growth
of the eye.
spectacles helps to maintain high binocular visual acuity, reduce or eliminate
heterophoria. Moving the visual axes of the eyes along the horizontal of the
lenses Perifocal with asymmetric addition and with its asymmetric beginning
creates, depending on the angle of deviation of the visual axes, monocular
micro blurring of the visual image or, with a small difference in the degree of
severity for each eye, binocular micro blurring of visual images, which causes
a soft dissociation of the binocular visual image. Mild dissociation of
binocular visual image, according to the canons of orthoptic and diploptic
, is an incentive to enhance the correspondence between the retinas and the
development of bifoveal fusion, which helps to preserve the binocular visual
acuity and reducing or eliminating heterophoria.
study of the perifocal spectacle lenses effect on axial and peripheral
refraction in patients with myopia, conducted in 2013 - 2014, Helmholtz eye
research institute of the Ministry of health of Russia, identified and
confirmed the multifactorial effect of Perifocal spectacles in progressive
myopia contributing to the stabilization of refraction, or a significant
slowdown in its progression.
various studies conducted by different institutions [36,38-41] the high
efficiency of Perifocal spectacles in the impact on the progression of myopia,
which according to the authors is in the range of 49 - 60%. The long-term
results of study, conducted in Helmholtz eye research institute of the Ministry
of health of Russia, for the period of 4 - 5 years of Perifocal spectacles using
in children showed a decrease in the rate of myopia progression from the
initial 0.8D up to 0.17D and a 60% reduction in the rate of myopia progression compared
to the control group of children wearing monofocal spectacles.
unique optical features Perifocal lens creates conditions for versatile
functional impact on various eye systems in order to prevent the progression of
myopia. Perifocal spectacles can be used at any age to train accommodation,
relieve eye spasm, prevent the development and progression of myopia.
features of the Perifocal lens create the conditions for a versatile functional
effect on various eye systems, which leads to stabilization or slowing down of
refraction myopization in myopes. Spectacles with perifocal defocus can be used
at any age to prevent the development and progression of myopia, to overcome
the usual excess tension of accommodation, to improve accommodation functions and
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