ophthalmology

1. Myopia
PAVITHRA.A

2. Emmetropia
 Optically normal eye
 State of
refraction,where in
parallel rays of light
coming from infinity are
focused at a sensitive
layer of retina with
accommodation being at
rest

3. Ametropia
 Condition of refractive error
 State of refraction,when parallel rays of light
coming from infinity are focused either in front or behind
the sensitive layer of retina in one or both meridians
It includes:
Myopia
Hypermetropia
Astigmatism

4. Myopia
 Shortsightedness
 Type of refractive error
 Parallel rays coming from
infinity are focused in front of
retina when accomodation
at rest

5. Etiological classification
 Axial myopia
 Curvatural myopia
 Positional myopia
 Index myopia
 Myopia due to excessive accomodation

6. Grading of myopia
 American optometric association
 3 grades
Low myopia,when the error is ≤ -3D
Moderate myopia,when the error is b/w -3D to -6D
High myopia,when the error is ≥-6D

7. Clinical varieties of myopia
 Congential myopia
 Simple or developmental myopia
 Pathological or degenerative myopia
 Acquired or secondary myopia which occurs
Secondary to some other diseases:
Post traumatic
Post keratitic
Drug induced
Pseudomyopia
Space myopia
Night myopia
Consecutive myopia

8. Congenital myopia
 Present since birth – diagnosed by age of 2-3 years
 Anisometropia present – unilateral
 High degree of error 8-10D  constant
 Convergent squint- 10-12cm
 Early correction-desirable
 Asssociations- cataract,microphthalmos,aniridi,
Megalocornea and congenital separation of retina

9. Simple myopia
 Most commonest
 Considered as physiological error not associated with any
disease of eye
 School going age b/w 8-12 years-SCHOOL MYOPIA

10. Etiology
 Results from normal biological variation in the development of eye
 May or may not be genetically determined
 Factors associated with simple myopia
Axial type-physiological variation in length of eyeball or may be associated with
precocious neurological growth during childhood
Curvatural type – underdevelopment of the eyeball
Role of diet
Role of genetics – children with both parents myopic 20%
children with one parent myopic 10%
Children with no myopic parent 5%
Theory of excessive near work-close work,watching television,smart phones,computer
Limited outdoor activity

11. Clinical features
 Symptoms
 Main symptom-Poor vision for distance
 Asthenopic symptoms(Asthenopia –tiredness of eyes
relieved by closing the eyes)
 Half shutting of the eyes
 A change in psychological outlook of the uncorrected
myopic children

12. Signs
 Prominent eyeballs
 Anterior chamber-slightly deeper
 Pupils-large
 Fundus-normal
 Magnitude of refractive error– It occurs at 5-10 yrs
 Increases till about 18-20 years at a rate of -0.5±0.30
 Doesn’t exceed -6D

13. Pathological myopia
 Progressive error starts in childhood at 5-10 years
 Results in high myopia ≥-6D during early adult life
 Associated with degenerative changes in the eye

14. Etiology

15.  Defective vision
 Muscae volitantes-floating black opacities In front of
eyes- due to degenerated liquified vitreous
 Difficulty in night vision
Symptoms

16. Signs
 Prominent eyeballs
 Cornea-large
 Anterior chamber-deep
 Magnitude of refractive error-increases rapidly and vary from -10D to -40D
 Fundus examination
Optic disc – Large,pale
Myopic cresent-tempor edge
. Peripappillary cresent- encircling the disc
Choroid and retina- distracted away from disc margin
Supertraction cresent-retina is pulled over disc margin- nasal side

17.  Degenerative change in retina and choroid
 Chorioretinal atrophic patches at macula
 Foster-fuchs’spot-dark red circular patch due to sub retinal
neovascularization and choroid haemorrhage
 Cystoid degeneration
 Lattice degeneration and snail track lesions
 Total retinal atrophy
 Posterior staphyloma
 Due to ectasia of sclera at posterior pole
 Degenerative changes in vitreous
 Liquefaction,vitreous opacities,posterior vitreous detachment
appearing as Weiss reflex
 Visual fields-contraction
 ERG-subnormal electroretinogram-chorioretinal atrophy

18. Complications
 Retinal detachment
 Complicated cataract
 Vitreous haemorrhage
 Choroidal haemorrhage
 Strabismus fixus convergence
 Primary open angle glaucoma – not a complication

19. Treatment
 Optical treatment
Concave lens
Spectacles and Contact lens
 Surgical treatment
 Cornea based procedures
Radial keratotomy
Laser ablation
Refractive lenticule extraction
Intracorneal ring implantation
OrthoKeratology

20. Lens Based procedures
 Refractive lens exchange
 Phakic refractive Lens

21. Preventive measures
 Prevents progression of myopia:
Atropine drops 0.01% at night
Pirenzepine 2%gel twice a day
 General measures:
Balanced diet
Early management
Visual hygiene-Proper posture,adequate
illumination,Continuous reading at night should be avoided
Avoidance of excessive near works-Avoid usage of video display
units

22. Thank You😁