Studying Refractory errors along with homoeopathic therapeutics.

2.  Ametropia results from an imbalance between
the refractive power and the axial length of the
eye. In this case, instead of sharp image, blur
circle forms which is proportional to the size of
refractive error and pupil. The power of the eye
to focus and see an image clearly is dependent
on several structures within the eye. The
distortion in the components of eye structure
may lead to errors of refraction.

3.  Cornea
 The cornea is a transparent dome-shaped tissue that forms the
front part of the eye. It functions as a window and allows light
to enter the eye. It also begins the process of focusing light rays.
 Lens
 The lens is composed of transparent, flexible tissue, located
directly behind the iris and the pupil. It is the second part of the
eye, after the cornea, which helps to focus light and images on
the retina. Because the lens is flexible and elastic, it can change
its curved shape to focus on objects and people that are either
nearby or at a distance.
 Retina
 The retina is light-sensitive tissue that lines the inside surface of
the eye. Visual information is transmitted from the retina to the
brain by the optic nerve.

4.  To see as clearly as possible, images must be
focused by the cornea and lens directly onto the
retina. In order for vision to be as sharp as
possible, the focusing power of the lens and cornea
must correspond appropriately to the length of the
eye so that the light rays ultimately come together
at the retina.
 The relaxed and focused state of the normal eye on
an object more than 6 meters or 20 feet away is
called Emmetropia. The light rays coming from
that object are essentially parallel, and the rays are
focused on the retina without effort.

5.  If they focus either in front of the retina or
behind the retina, the image becomes unclear
or blurred, and it is called as refractive error

6.  Myopia - Difficulty in seeing distant objects clearly is called
myopia or nearsightedness. Close objects are clear, and distant
objects are blurry.
 Hyperopia - Difficulty in seeing close objects clearly is called
hyperopia or hypermetropia or farsightedness. Close objects are
more blurry than distant objects.
 Astigmatism - Distorted vision resulting from an irregularly
curved cornea is called astigmatism.
 Presbyopia - Presbyopia is a natural occurrence in which the eye
can no longer focus near objects leading to difficulty in reading or
seeing near objects, it is linked to ageing and occurs almost
universally.
 Anisometropia - Anisometropia is the condition in which the
two eyes have unequal refractive power. Generally, a difference in
power of two diopters or more is the accepted threshold to label the
condition anisometropia.
 Antimetropia - Antimetropia is the condition of each eye being
nearsighted, farsighted or a combination of both.

7.  Common name:
 Causes:
 Diagram:

8.  Common name: near-sightedness
 Causes: long eyeball or overly curved cornea
 Diagram:
 Why can myopic individuals see close objects better?
Because light from close objects diverges more / needs
more refraction or greater distance to properly hit the
retina

9.  Correction:
 Concave corrective lenses / contacts
magnify the image (make the light diverge more),
before it enters the eye
 Lasik surgery to flatten cornea
makes the light focus less so it can properly reach the
retina.

10.  Common name:
 Causes:
 Diagram:

11.  Common name: farsightedness
 Causes: short eyeball or a lens that does not bulge
enough
 Diagram:
 Why can hyperopic individuals see distant objects better?
Because light from distant objects is parallel, requiring less
refraction or less distance to properly hit the retina

12.  Correction:
 Convex corrective lenses / contacts
 Cornea surgery to make the cornea more rounded
 Both focus the light more so that it properly reaches retina

13.  A-stigma = not a point (light focuses unevenly on
retina)
 Causes:
 Diagram:

14.  A-stigma = not a point (light focuses unevenly on
retina)
 Causes: Irregularly shaped cornea or lens
 Diagram:

15.  Signs of astigmatism:
 Fine details are blurry – whether near or far
 “Halo”effects or glare from lights

16.  Correction
 Corrective lenses or contacts
 Shape of lens /contact varies across the surface to
counteract irregular shape of the eye
 Contact lenses are often weighted so that they align
properly with the eye
 Ortho-K / cornea surgery
 Reshape cornea with special
contact lenses worn at night
or with laser surgery

17. Show with fingers –
1) Myopia, concave lens
2) Myopia, convex lens
3) Hyperopia, concave lens
4) Hyperopia, convex lens
5) Astigmatism, uneven lens

18. Show with fingers –
1) Myopia, corrected with concave lens
2) Myopia, corrected with convex lens
3) Hyperopia, corrected with concave lens
4) Hyperopia, corrected with convex lens
5) Astigmatism, corrected with uneven lens

19.  PHYSOSTIGMA - Pysostigma is prescribed for
nearsightedness which is progressing rapidly,
accompanied by pain in the orbits. The person
experiences photophobia along with blurred vision.
Spasm of the ciliary muscle, irritability of the eyes and
dim vision are present in Pysostigma.
 RUTA GRAVEOLENS - Ruta is effective for myopia
with severe headache. Heacahe occurs while reading,
sewing and performing other near-sighted activities.
Weakness of the ciliary muscles and blurred vision are
also present. Ruta acts very well for eyestrain
occurring from overuse of eyes.

20.  AGARICUS MUSCARIUS - The person
experiences difficulty in reading , as type seems to
move or to swim. Double vision with flickering
before the eyes. Asthenopia from prolonged strain,
spasm of accommodation. There is twitching of
lids eye balls. Margin of the lids red, itch and burn
 VIOLA ODORATA - Viola Odorata is another
medicine for Myopia, where it is accompanied by
severe pain in the eyes. The person complains of
severe pain in the eyes which radiates to the top of
the head. Other prescribing symptoms are
heaviness of the eyelids, flames before the eyes
and nearsightedness.

21.  OLEUM ANIMALE –
 blurred vision with smarting in the eyes. The person
often sees glistening bodies before his eyes and
complains of dim vision. Nearsightedness
accompanied by twitching of the eyelids is another
prescribing symptom
 LILIUM TIGRINUM -Lilium tig is best for
Myopia , there is myopic astigma. There is
impaired vision , pain extending back .
Hyperesthesia of the retina. Lilium tig is useful
in restoring the power of weak ciliary muscles.

22.  PHOSPHORUS –
 Fatigue of the eyes and head even when the eyes are
not being overused is a key symptom for
prescription of Phosphorus. It is prescribed for
myopia with weak eyesight and an aversion to light.
A feeling of having sand in the eyes which gets
better by rubbing may also be present. Frequent
itching in the eyes with profuse lachrymation is also
present. Phosphorus is effective for the treatment
of nearsightedness with atrophy of optic nerve .