This document discusses different types of myopia (nearsightedness). It defines myopia as a refractive error where parallel rays of light from infinity are focused in front of the retina. It describes the different classifications of myopia including by etiology (cause), degree, age of onset, and association with other ocular conditions. For example, it distinguishes between congenital myopia present from birth and simple/developmental myopia which begins later in childhood. It provides details on examinations and treatments used to diagnose and manage different levels of myopia.

2. Short sightedness

3.  Refractive error
 Parallel rays of light coming from
infinity are focused in front of the
retina
 Accommodation is at rest

4. 2x risk 5-6x risk
<1.5 hours
>3 hours
2.6x risk
⦿ Children most at risk=
Outdoor time Nearwork
⦿ Children with
emmetropia spend 3.7
hoursper week more
outdoors than those
with myopia 6
40- 80 minutes ↓23% to 50%
13
⦿ Light level
› Light towards the UV
end of the spectrum
slows eye growth and
myopia

5.  Axial
 Curvatural
 Positional
 Index
 Myopia due to excessive accommodation

6.  Congenital Myopia
 Simple / developmental Myopia
 Degenerative / pathological Myopia
 Acquired myopia

7.  Low Myopia(<3D)
 Medium Myopia(3-6D)
 High Myopia(>6D)

8.  Congenital Myopia
 School Myopia(<20 yrs of age)
 Early Adult-Onset Myopia(20-40 yrs of age)
 Late Adult-Onset Myopia(>40 yrs of age)

9. CONGENITAL MYOPIA
Increase in axial length
Increase in Overall globe size
Since birth, diagnosed at age 2-3 years
If unilateral, as anisometropia, may develop amblyopia, strabismus
Usually 8-10 D, remain constant
Bilateral- difficulty in distant vision, hold things very close

10. Physiological error not associated with any disease of the eye
Etiology :
Normal biological variation in development of eye
Inheritence
Associated factors
Role of diet
Theory of excessive near work

11. Clinical picture
Rarely present at birth
Rather born hypermetropic, become
myopic
Begins at 7-10 years, stabilizing
around mid teens
Usually around 5D, never exceeds 8D
Signs
Large and prominent
Deep AC
Large, sluggishly reacting pupils
Normal fundus, rarely crescent
Usually doesn't exceed 6-8D
 Retinoscopy under full cycloplegia

12. PATHOLOGICAL / DEGENERATIVE /
PROGRESSIVE MYOPIA
Rapidly progressive associated with degenerative changes in the eye
Etiology
Rapid axial growth of the eyeball outside the normal biological variations of
development
Role of heredity
Role of general growth process

13. Genetic factors General growth process
More growth of retina
Stretching of sclera
Increased axial length
Degeneration of choroid
Degeneration of retina
Degeneration of vitreous

14. Symptoms
Defective vision
Muscae volitantes / floating black
opacities
Signs
 EYE Large, prominent eyes
simulating exophthalmos
 CORNEA large
 ANTERIOR CHAMBER deep

15. FUNDUS
 VITEROUS degeneration,viterous
liquefication,vitreous detachment
present as WEISS REFLEX
 SCLERA thinning/ STAPHYLOMA
 VISUAL FIELD DEFECTS show
Contraction and in some ring
scotomas present

16.  DISC
 Large in size
Myopic Crescent on the temporal
side of the disc
Choroidal Crescent
Peripapillary Atrophy

17.  MACULA
Foster-Fuchs fleck
RETINAL DETACHMENT
POSTERIOR STAPHYLOMA
RETINAL HOLES
TESSELLATED FUNDUS

18. Optical treatment
Appropriate concave lenses
Minimum acceptance providing
maximum vision

19.  Spectacles
 Contact lens
base to base
plus lens
apex to apex
minus lens

20. Radial keratotomy
Phototherapeutic keratectomy
Intra corneal ring implantation
Phakic IOL’S
LASIK (LASER assisted insitu
keratomileusis)