Page 116 - The Indian Optician Digital Edition May-Junel 2022
P. 116
CONSEQUENCES OF
AVOIDING
OPTICAL AIDS
t is good to have two eyes, better to have 6/6 vision in both
these eyes, and it is the best to have perfect alignment as well
Ias co-ordination in them. Unfortunately, some individuals are
not so fortunate to have all these in perfect order.
As the human eyes are not mould crafted, they have
SANJAY K MISHRA inherent optical imperfections, called aberrations. These can be
SCIENTIST, DR. R P CENTRE classified as below:
FOR OPHTHALMIC SCIENCES, AIIMS,
NEW DELHI
Emmetropia – is a condition in which the parallel rays of
light from infinity come and focus onto the retina. (figure 1)
Ametropia – in this condition the rays do not focus on the
retina, they focus elsewhere. This condition is commonly known
as refractive error. The refractive errors can be further classified
in three forms such as:
Myopia – a condition of refractive error in which the eye
ball is usually bigger than normal in size and therefore, the
parallel rays of light coming from infinity get focused in front
VIBHA KUMARI of the retina when accommodation is relaxed. (see figure 2)
ASSTT PROF, PROGRAM
CO-ORDINATOR, SCHOOL OF NURSING Hypermetropia/Hyperopia – this refractive error condition
SCIENCES & ALLIED HEALTH, JAMIA
HAMDARD manifests in an eye ball that is usually smaller than normal
in size and therefore, the parallel rays of light coming from
infinity get focused beyond the retina when accommodation
is relaxed. (see figure 3)
Astigmatism – is a unique condition in which the eye ball is
not a perfect spheroid and the parallel rays of light do not
have one focal point. Instead, they have a range of locations
in which light from different meridians get focussed. (see
figure 4)
VIKAS SHRIVASTAVA OPTICAL CORRECTION
ASSISTANT PROF. & HOD,
DEPARTMENT OF OPTOMETRY, Optical correction of the refractive errors using either
SCHOOL OF MEDICAL & ALLIED spectacles or contact lenses helps the patients to get clear and
SCIENCES, GALGOTIAS UNIVERSITY,
GREATER NOIDA comfortable vision. Additionally, it reduces the tendency for
112 THE INDIAN OPTICIAN MAY-JUNE 2022 OPTOMETRY
