HONG KONG, April 18, 2018 /PRNewswire/ --
A specially designed spectacle lens developed by The Hong Kong
Polytechnic University (PolyU) was found to have slowed down myopia
progress by 60% in participating children, and 21.5% of them had
their myopic progression halted completely. This lens will be
launched in summer this year, offering a non-contact, spectacle
lens solution to myopic children.
(Photo:
https://mma.prnewswire.com/media/678860/PolyU_Myopia_Research.jpg
)
The Defocus Incorporated Multiple Segments (DIMS) Spectacle Lens
designed by Professor Carly Lam,
Professor of the School of Optometry at PolyU, and Professor To
Chi-ho, Henry G. Leong Professor in Elderly Vision Health and Head
of the School, is designed for slowing myopic progression in
children. It has won the Grand Prize, Grand Award and
Gold Medal with the Congratulations of Jury at the 46th
International Exhibition of Inventions of Geneva, 2018.
DIMS Spectacle Lens comprises of a central optical zone for
correcting refractive error (i.e. myopia and astigmatism) and
multi-segments of constant myopic defocus surrounding the central
zone extending to mid-periphery of the lens. It provides clear
vision and myopic defocus for vision correction simultaneously for
the wearer at all viewing distances. In doing so, the lens makes
use of the natural homeostatic mechanism known as
'emmetropization', whereby the eyeball adapts and shapes to receive
focused images as it does for normal vision.
"We have tried to incorporate myopic defocus optics into
different treatment modalities, such as contact lens. For spectacle
lens, the challenge is the eye will move behind the spectacle lens
and therefore the myopic defocus optics has to be incorporated all
over the lens," said Professor To.
"With the DIMS Spectacle Lens, we are able to put in many
micro-lenses all over the surface of the ophthalmic lens. When the
eye moves around different regions of the spectacle lens, the eye
still experiences a constant amount of myopic defocus," he
added.
A total of 160 Chinese children aged 8 to 13, with myopia from 1
to 5 diopters (D), and astigmatism and anisometropia of 1.5D or
less completed a randomised double-blinded clinical trial from
August 2014 to July 2017.
Seventy-nine and eighty-one children were randomly assigned to
wear the DIMS Spectacle Lenses (treatment group) and the single
vision spectacle lenses (control group) respectively. The mean
myopic progression of the treatment group over two years was 0.38D
whereas the control group was 0.93D. (Appendix Table 1)
Myopia occurs when the eyeball is too long relative to the
focusing power of the cornea and lens of the eye. Light focuses in
front of the retina rather than on it, making distant objects
appear blurry. In the trial, the mean increase in eyeball axial
length of the treatment group was 0.21mm while the control group
was 0.53mm. (Appendix Table 2)
In other words, children wearing the DIMS Spectacle Lenses had
significantly less myopic progression by 59%, and axial elongation
by 60%, as compared with those wearing the single vision
lenses.
For the individual, in addition to slow myopic progression, the
study shows that wearing DIMS Spectacle Lens stops the progression
of myopia in some children. 21.5% of children in the treatment
group had no myopic progression whereas only 7.4% of children in
the control group had no myopic progression. (Appendix Table 3)
Besides, 13.9% of children in the treatment group had no change
in axial length changes whereas the control group recorded zero.
(Appendix Table 4)
The children in the treatment group also indicated that the DIMS
Spectacle Lens could provide comfortable, good vision at short and
long distances, and good perception of depth same as single vision
spectacle lens.
"High myopia can cause retinal complications. The serious case
could be a retinal detachment that may result in permanent
blindness or visual impairment. The DIMS Spectacle Lens helps
safeguard the vision of children," said Professor Lam.
The DIMS Spectacle Lens is licensed to a lens company
experienced in eyeglass lenses and will be available in the market
in this summer.
Table 1
Changes in Cycloplegic auto-refraction in SER (D)
Mean diff plus or minus
SE
Mean plus or
minus SD DIMS (n=79) Control (n=81) (p value)
-0.13 plus or -0.24 plus or minus
minus 0.30 0.05
-0.37 plus or
6-month minus 0.34 (<0.0001****)
-0.17 plus or -0.55 plus or -0.38 plus or minus
minus 0.47 minus 0.38 0.07
12-month (<0.0001****)
-0.31 plus or -0.72 plus or -0.42 plus or minus
minus 0.50 minus 0.49 0.08
18-month (<0.0001****)
-0.55 plus or minus
0.09
-0.38 plus or -0.93 plus or
24-month minus 0.53 minus 0.58 (<0.0001****)
Table 2
Changes in axial length (mm)
Mean diff plus or minus
SE
Mean plus or (p value of unpaired
minus SD DIMS (n=79) Control (n=81) t-test )
0.03 plus or 0.20 plus or
minus 0.13 minus 0.10 0.16 plus or minus 0.02
6-month (<0.0001****)
0.11 plus or
minus 0.15 0.21 plus or minus 0.02
0.32 plus or
12-month minus 0.16 (<0.0001****)
0.15 plus or 0.43 plus or
minus 0.18 minus 0.19 0.27 plus or minus 0.03
18-month (<0.0001****)
0.21 plus or 0.53 plus or
minus 0.22 minus 0.24 0.31 plus or minus 0.04
24-month (<0.0001****)
Table 3
Myopic progression in 24 months
among individuals in two groups
No. and % of subjects
Changes in SER (D) DIMS Control
<-1 10 (12.7%) 34 (42%)
-0.5 to -1 16 (20.3%) 30 (37%)
-0.01 to -0.49 36 (45.5%) 11 (13.6%)
62 (78.5%) 75 (92.6%)
Subtotal of subjects
with myopic progression
0 to 0.5 15 (19.0%) 6 (7.4%)
>0.5 2 (2.5%) 0 (0%)
6 (7.4%)
Subtotal of subjects
without myopic
progression 17 (21.5%)
Total 79 (100%) 81 (100%)
Table 4
Axial elongation in 24 months among
individuals in two groups
No. and % of subjects
Change in AL (mm) DIMS Control
greater than or equal
to 0.3 23 (29.1%) 68 (84%)
>0 and <0.3 45 (57%) 13 (16%)
0 or less 11 (13.9%) 0 (0%)
Total 79 (100%) 81 (100%)
Press Contact : Professor Carly
Lam
Professor of the School of Optometry, PolyU
Telephone : +(852)-2766-6091
E-mail :carly.lam@polyu.edu.hk
Press Contact : Professor To Chi-ho
Henry G. Leong,
Professor in Elderly Vision Health and Head of the School of
Optometry
PolyU
Telephone : +(852)-2766-6102
E-mail :chi-ho.to@polyu.edu.hk