Page 103 - The Indian Optician Digital Edition November-December 2021

from +0.40 D to +1.10 D, it is
suggested, as a guideline, that
the additions be offered as
shown in the following Table.
For near vision at 40cm,
an emmetrope would
need to exert +2.50 D of
accommodation. With the
Eyezen™ Boost lens this value
would reduce by the amount
shown in Table 1 depending
upon which supportive
FIGURE 1 - OFF-AXIS
PERFORMANCE OF POINT addition the practitioner has
FOCAL LENS +4.00 D LENS prescribed.
WITH SPHERICAL SURFACES
DESIGNED FOR DISTANCE VISION
The Eyezen™ Boost series
also incorporates Essilor’s Eye
objects at different distances including changing from distance Protect System which filters
to intermediate to near vision, indicates several different factors the blue-violet waveband
which should be taken into account when designing single vision below 455nm to further relieve
lenses. The most important results from the research indicated the eye of the computer vision
that smart phones and tablets are held at closer distances syndrome.
and different inclinations from A4 pages and newspapers. The EYEZEN™ START LENSES
working distance depends upon the sizes of the screen and the
font. The smaller text that is employed on the small screens of A new aspheric lens has
smart phones tends to result in the device being held closer to the been introduced by Essilor,
eyes than other near vision material. which has no near addition
to support accommodation
Concern has also been expressed about the possible harmful but instead, provides best-
radiation emitted by blue-rich sources and several series of lenses form performance in both the
from different manufacturers have incorporated protection from distance and the near zones for
blue light, particularly in the waveband below 455nm. pre-presbyopic subjects. Typical
EYEZEN™ BOOST LENSES modern best form spectacle
lens series are optimised for
The Eyezen™ Boost series of lenses provides a small addition distance vision since optimum
of power in the near zone of the lens and is intended for use by visual acuity is generally
young people who spend a lot of time viewing digital devices required to observe fine detail
such as smart phones, tablets, laptop and computer screens in the distance. Near vision
but do not yet require a separate correction for near vision. tasks are relatively coarse, for
Eyezen™ Boost is a variation-power lens with a low addition for example N5 type held at 35 cm
near, intended to relieve accommodation during long periods of can be read by a subject who
close work. Available with four different near additions ranging possesses a visual acuity of little
better than 6/12 for distance
TABLE 1 RECOMMENDED ADDITIONS BY AGE GROUP vision. Research, however, has
shown that the correction of
age group addition
small astigmatic refractive
young adults 18 to 34 +0.40 errors may be important in
pre-presbyopes 35 to 39 +0.60 optimising patient comfort
during computer operation
5
emerging presbyopes 40 to 50 +0.85 or +1.10 so that reducing aberrational

99 | LENS TALK