Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
MYOPIA
MANOJ ARYAL
1
B. Optometry IOM
Maharajgunj Medical Campus
PRESENTATION LAYOUT
2
 Introduction
 Optics of myopia
 Classification
 Treatment of myopia
 Prognosis
3
EMMETROPIA
 When parallel rays of light coming from infinity are
focused in sensitive layer of retinawith
accommodation...
4
AMETROPIA
 Parallel rays of light coming from infinity (with
accommodation at rest) are focused either in front
or behi...
5
TYPES OF AMETROPIA
myopia
astigmatism
hypermetropia
Introduction
 Derived from two Greek root words
 (Greek: μυωπία, muōpia, from myein "to shut" - ops
(gen. opos) "eye“)
...
Optics of myopia
 The optical system is too powerful for its axial length.
 Image of distant object on retina is made up...
Optics of myopia
 Nodal point is further away from retina.
 Accommodation in uncorrected myopes is not
developed normall...
Image formation
 In myopia image formed in front of eye which
is corrected by placing the negative lenses.
9
TYPES OF MYOPIA
10
 Etiologically
 Axial myopia :result from increase in anterioposterior
length of eyeball.
 Curvatura...
TYPES OF MYOPIA CONTD…
 Clinically,
 congenital myopia.
 simple or developmental myopia.
 pathological or degenerative...
Congenital myopia
 Present since birth.
 Seen more frequently in children who were born
prematurely or with various birt...
Congenital myopia contd..
 Early correction is desirable to help the children to
develop normal distance vision and perce...
Simple myopia
 Aka physiological or school myopia.
 Physiological error not associated with any disease of
eye.
 Etiolo...
Simple myopia etiology
Axial Physiological variation in
the length of the eyeball.
Curvatural Underdevelopment of
eyeball....
Simple myopia contd…
 Clinical pictures:
Symptoms:
 Poor vision for distance.
 Asthenopic symptoms
eye strain due to
di...
Degree of myopia Visual acuity
-0.50 6/9-6/12
-1.00 6/18
-1.50 6/24
-2.00 6/36
-3.00 6/60
-4.00 4/60
-5.00 3/60
-6.00 2/60...
Simple myopia: SIGNS
 Eyes are large and prominent.
 Slight deep anterior chamber.
 Fundus is normal :rarely temporal m...
Simple myopia :diagnosis
 Confirmed by performing retinoscopy.
19
Pathological myopia
 Rapidly progressive error resulting in high myopia
usually apparent during 1st decade of life charac...
Pathological myopia contd
 However it is confirmed that genetic factors play a major
role.
 It is said that increased ax...
22
Genetic factors General growth
(play major role)
↓
More growth of retina
↓
Stretching of sclera
↓
Increased axial lengt...
Pathological myopia contd…
23
 Symptoms
 defective vision.
 muscae volitantes.
 night blindness.
Pathological myopia contd…
 Signs:
 Eyes are prominent, appearing elongated, and even
stimulating an exophthalmos.
 Cor...
25
Retinal changes in pathological myopia
 Optic disc:
 appears large and pale
 at temporal edge a characteristic myopi...
26
 Foster- Fuchs spot may be present at macula
 It is a raised, circular, pigmented lesion developing after a
subretina...
27
 A posterior staphyloma is an ectasia or bulging of the
posterior sclera due to focal expansion and thinning .
 It oc...
28
Fundus changes in myopia
Foster-Fuch’s
spotPeripapilary
and macular
degeneration
29
Choroidal neovascularization
associated with
a lacquer crack and high
myopia.
Peripheral retinal degernerations :
A:Lat...
30
Pathological myopia :complications
 Rhegmatogenous retinal detachment (RD) is much more
common in high myopia, the pat...
31
Systemic associations of high myopia
• Down syndrome
• Stickler syndrome
• Marfan’s syndrome
• Prematurity
• Noonan syn...
32
Acquired myopia
 Causes:
 index myopia : seen in nuclear sclerosis.
incipient cataract.
diabetic myopia occurs due to...
33
Acquired myopia contd..
 consecutive myopia
surgical overcorrection of hypermetropia
pseudophakia with overcorrecting ...
Acquired myopia contd…
 Pseudo myopia correction
 Cycloplegic refraction
-always prescribe plus lenses.
34
35
Acquired myopia contd..
 space myopia
experienced when the individual has no stimulation
for distance fixation.
never ...
Acquired myopia contd…
 Night myopia or twilight myopia
36
The emmetropic eye ,if accomodated for
the middle range of vis...
37
Acquired myopia contd…
 drug induced myopia
cholinergic drugs such as pilocarpine, echothiopate,
di-isopropyl fluoroph...
TYPES OF MYOPIA CONTD…
 According to amount:
 Classically:
 Very low : upto – 1.00D
 Low : –(1.00-3.00)D
 Medium : –(...
TREATMENT OF MYOPIA
39
 Optical treatment
 Surgical treatment
 General measures
 Visual hygiene
 Low-vision aids
Optical treatment
40
Include prescription of appropriate concave lens
minimum acceptance providing maximum vision
should b...
Optical treatment CONTD…
41
Guidelines for correcting low degree of myopia upto -
6D
 Children younger than 8yr should be...
Optical treatment CONTD…
42
 guidelines for correcting high myopia
 full correction can rarely be tolerated.
 undercorr...
43
Modes prescribing concave lenses
 Spectacles
 Contact lenses
44
TREATMENT OF MYOPIA
OPTICAL PRINCIPAL
UNCORRECTED
CORRECTED WITH GLASS
CORRECTED WITH CONTACT LENS
Prescription of appr...
Surgical treatment:
45
Radial keratotomy
 Making deep (90 percent thickness radial incision in
the peripheral cornea leav...
46
Photorefractive keratectomy
 Photoablation of excimer LASER.
 Which can accurately ablate corneal tissue to an exact
...
47
 LASIK
Laser in situ keratomileusis
Currently most frequent performed refractive
procedure.
Can correct myopia upto -1...
General measures:
48
Balanced diet rich in vitamins and proteins
Early management of associated debiliating
diseases.
Visual hygienes:
49
to avoid asthenopic symptoms
adequate illumination during close work
clarity of print should be good t...
Low vision aids:
50
Indicated in patients of progressive myopia with
advanced degenerative changes where useful
vision can...
Prophylaxis
51
 genetic counseling for people having
pathological myopia, not to marriage with
pathological myopic people...
PROGNOSIS
52
Simple myopia
Prognosis is good.
Error usually does not progress beyond 6-8D
Stablizes by the age of 21
Patho...
References
53
Theory and practice of optics and
refraction by AK Khurana
Borish’s clinical refraction
Internet
54
Upcoming SlideShare
Loading in …5
×

MYOPIA

19,892 views

Published on

myopia

Published in: Education
  • Follow the link, new dating source: ❤❤❤ http://bit.ly/39sFWPG ❤❤❤
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Dating for everyone is here: ❶❶❶ http://bit.ly/39sFWPG ❶❶❶
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • DOWNLOAD FULL eBOOK INTO AVAILABLE FORMAT ......................................................................................................................... ......................................................................................................................... 1.DOWNLOAD FULL. PDF eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. PDF eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, CookeBOOK Crime, eeBOOK Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • DOWNLOAD FULL eBOOK INTO AVAILABLE FORMAT ......................................................................................................................... ......................................................................................................................... 1.DOWNLOAD FULL. PDF eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. PDF eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc eBook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, CookeBOOK Crime, eeBOOK Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

MYOPIA

  1. 1. MYOPIA MANOJ ARYAL 1 B. Optometry IOM Maharajgunj Medical Campus
  2. 2. PRESENTATION LAYOUT 2  Introduction  Optics of myopia  Classification  Treatment of myopia  Prognosis
  3. 3. 3 EMMETROPIA  When parallel rays of light coming from infinity are focused in sensitive layer of retinawith accommodation being at rest.  Components that maintain emmetropization are axial length AC depth corneal curvature
  4. 4. 4 AMETROPIA  Parallel rays of light coming from infinity (with accommodation at rest) are focused either in front or behind retina. Further classified into  Myopia :where the parallel rays of light coming from infinity are focused in front of retina.  Hypermetropia: where the parallel rays of light are focused behind the sensitive layer of retina.  Astigmatism :where the refraction varies in different meridia.
  5. 5. 5 TYPES OF AMETROPIA myopia astigmatism hypermetropia
  6. 6. Introduction  Derived from two Greek root words  (Greek: μυωπία, muōpia, from myein "to shut" - ops (gen. opos) "eye“)  Myopia or shortsightedness is a type of refractive error in which parallel rays of light coming from infinity are focused in front of retina with the accommodation is at rest. 6
  7. 7. Optics of myopia  The optical system is too powerful for its axial length.  Image of distant object on retina is made up of circle of diffusion formed by divergent beam since the parallel rays of light coming from the infinity are focused in front of the retina.  Far point is finite point in front of eye. 7
  8. 8. Optics of myopia  Nodal point is further away from retina.  Accommodation in uncorrected myopes is not developed normally,they may suffer from convergence insufficiency, exophoria,and early presbyopia as they grow. 8
  9. 9. Image formation  In myopia image formed in front of eye which is corrected by placing the negative lenses. 9
  10. 10. TYPES OF MYOPIA 10  Etiologically  Axial myopia :result from increase in anterioposterior length of eyeball.  Curvatural myopia :occurs due to increased curvature of cornea or lens or both.  Index myopia :increase in refractive index of crystalline lens assotiated with nuclear sclerosis.  myopia due to excessive accommodation :occurs in patients with spasm of accommodation.
  11. 11. TYPES OF MYOPIA CONTD…  Clinically,  congenital myopia.  simple or developmental myopia.  pathological or degenerative myopia.  acquired myopia. 11
  12. 12. Congenital myopia  Present since birth.  Seen more frequently in children who were born prematurely or with various birth defects.  Usually error is about 8-10D, which mostly remains constant.  May sometimes be associated with other congenital anomalies such as cataract, microphthalmos, aniridia, megalocornea. 12
  13. 13. Congenital myopia contd..  Early correction is desirable to help the children to develop normal distance vision and perception of world. Full cycloplegic refractive error including any astigmatic correction should be prescribed. 13
  14. 14. Simple myopia  Aka physiological or school myopia.  Physiological error not associated with any disease of eye.  Etiology: result from normal biological variation in the development of eye. 14
  15. 15. Simple myopia etiology Axial Physiological variation in the length of the eyeball. Curvatural Underdevelopment of eyeball. -------- Role of diet in early childhood. -------- Theory of excessive near work. 15
  16. 16. Simple myopia contd…  Clinical pictures: Symptoms:  Poor vision for distance.  Asthenopic symptoms eye strain due to dissociation between convergence and accommodation. may develop convergence weakness and exophoria and supression in one eye.  Change in psychological outlook. 16
  17. 17. Degree of myopia Visual acuity -0.50 6/9-6/12 -1.00 6/18 -1.50 6/24 -2.00 6/36 -3.00 6/60 -4.00 4/60 -5.00 3/60 -6.00 2/60 17 Degree of myopia Rough estimate of visual acuity
  18. 18. Simple myopia: SIGNS  Eyes are large and prominent.  Slight deep anterior chamber.  Fundus is normal :rarely temporal myopic cresents may be seen.  Usually error does not exceed 6-8D 18
  19. 19. Simple myopia :diagnosis  Confirmed by performing retinoscopy. 19
  20. 20. Pathological myopia  Rapidly progressive error resulting in high myopia usually apparent during 1st decade of life characterized by increase in volume of posterior segment.  Etiology: no satisfactory hypothesis has emerged to explain the etiology of pathological myopia. 20
  21. 21. Pathological myopia contd  However it is confirmed that genetic factors play a major role.  It is said that increased axial length, degenerative changes in retina and vitreous, and pathological complications are determined by different genes.  Inheritance can be AD, AR ,X-LINKED 21
  22. 22. 22 Genetic factors General growth (play major role) ↓ More growth of retina ↓ Stretching of sclera ↓ Increased axial length ↓ Degeneration of choroid ↓ Degeneration of retina ↓ Degeneration of vitreous Features of pathological myopia etiological hypothesis for pathological myopia (Plays minor role) Elongation of the eyeball posterior to equator in pathological myopia.
  23. 23. Pathological myopia contd… 23  Symptoms  defective vision.  muscae volitantes.  night blindness.
  24. 24. Pathological myopia contd…  Signs:  Eyes are prominent, appearing elongated, and even stimulating an exophthalmos.  Cornea is large and anterior chamber is deep.  Pupils are larger  Refractive error: increase by as much as 4.00D yearly stabilizes at about the age of 20 but occasionally may progress until mid 30s`` frequently result in myopia of 10-20D 24
  25. 25. 25 Retinal changes in pathological myopia  Optic disc:  appears large and pale  at temporal edge a characteristic myopic crescent present.  Degenerative changes:  in retina and choroid are common.  occurs tigroid appearance of fundus due to diffuse attenuation of the RPE with visibility of large choroidalvessels.
  26. 26. 26  Foster- Fuchs spot may be present at macula  It is a raised, circular, pigmented lesion developing after a subretinal haemorrhage has been absorbed .  In advanced cases there occurs Focal chorio-retinal atrophy which is characterized by visibility of the larger choroidal vessels and eventually the sclera, total retinal atrophy, particularly at central area.  There may be associated lattice degeneration and or snail track lesions.  Retinal tears, haemorrhage , retinal detachment may be seen.
  27. 27. 27  A posterior staphyloma is an ectasia or bulging of the posterior sclera due to focal expansion and thinning .  It occurs in about a third of eyes with pathological myopia, and is virtually always peripapillary or involves the macula.Staphyloma development can be associated with macular hole formation.  Degenerative changes of vitreous include: liquefaction, vitreous opacities, PVD appearing as weiss reflex.  Visual field shows contraction and sometimes ring scotoma may be seen.
  28. 28. 28 Fundus changes in myopia Foster-Fuch’s spotPeripapilary and macular degeneration
  29. 29. 29 Choroidal neovascularization associated with a lacquer crack and high myopia. Peripheral retinal degernerations : A:Lattice degeneration, B:Snail track degeneration C:Acquired retinoschisis D:white-with-pressure E:Focal pigment clumps F:Diffuse chorioretinal degeneration G:Peripheral cystoid degeneration
  30. 30. 30 Pathological myopia :complications  Rhegmatogenous retinal detachment (RD) is much more common in high myopia, the pathogenesis including increased frequency of posterior vitreous detachment, lattice degeneration, asymptomatic atrophic holes, macular holes and occasionally giant retinal tears.  Foveal retinoschisis and macular retinal detachment without macular hole formation may occur in highly myopic eyes with posterior staphyloma, probably as a result of vitreous traction  Complicated cataract which may be either posterior subcapsular or early onset nuclear sclerotic.  Nuclear sclerosis.  Vitreous haemorrhages.  Choroidal haemorrhages and thrombosis.  Primary open angle glaucoma.
  31. 31. 31 Systemic associations of high myopia • Down syndrome • Stickler syndrome • Marfan’s syndrome • Prematurity • Noonan syndrome • Ehlers–Danlos syndrome • Pierre–Robin syndrome
  32. 32. 32 Acquired myopia  Causes:  index myopia : seen in nuclear sclerosis. incipient cataract. diabetic myopia occurs due to decrease in refractive index of cortex.  curvatural myopia increase of corneal curvature in diseased conditions like corneal ectasias, and conical cornea.  positional myopia: conditions producing anterior subluxation of lens.
  33. 33. 33 Acquired myopia contd..  consecutive myopia surgical overcorrection of hypermetropia pseudophakia with overcorrecting IOL.  pseudomyopia also called artificial myopia. produced in a conditions such as excessive accommodation and spasm of accommodation. may develop after too full a hypermetropic correction in children.
  34. 34. Acquired myopia contd…  Pseudo myopia correction  Cycloplegic refraction -always prescribe plus lenses. 34
  35. 35. 35 Acquired myopia contd..  space myopia experienced when the individual has no stimulation for distance fixation. never more than 0.75-1.50D
  36. 36. Acquired myopia contd…  Night myopia or twilight myopia 36 The emmetropic eye ,if accomodated for the middle range of visusal spectrum,will be slightrly myopic for the shorter wavelengths. Increased sensitivity to shorter wavelength of light Shift from photopic to scotopic vision at twilight
  37. 37. 37 Acquired myopia contd…  drug induced myopia cholinergic drugs such as pilocarpine, echothiopate, di-isopropyl fluorophosphate. sulphonamides.
  38. 38. TYPES OF MYOPIA CONTD…  According to amount:  Classically:  Very low : upto – 1.00D  Low : –(1.00-3.00)D  Medium : –(3.00-6.00)D  High : –(6.00-10.00)D  Very high : above –10.00D
  39. 39. TREATMENT OF MYOPIA 39  Optical treatment  Surgical treatment  General measures  Visual hygiene  Low-vision aids
  40. 40. Optical treatment 40 Include prescription of appropriate concave lens minimum acceptance providing maximum vision should be prescribed. never overcorrect myopia
  41. 41. Optical treatment CONTD… 41 Guidelines for correcting low degree of myopia upto - 6D  Children younger than 8yr should be fully corrected and instructed to use their glasses constantly  Adult younger than 30 yrs: usually accept their full correction.  Older than 30 yrs: not able to tolerate a full correction over 3D if they have never worn glasses before. prescribe less than full correction with which the patient has comfortable.
  42. 42. Optical treatment CONTD… 42  guidelines for correcting high myopia  full correction can rarely be tolerated.  undercorrect as little is compatible with comfort for binocular near vision.  undercorrection to the tune of 1-3D or even more may be required.  undercorrection is always better to avoid the problem of near vision and minification of image.
  43. 43. 43 Modes prescribing concave lenses  Spectacles  Contact lenses
  44. 44. 44 TREATMENT OF MYOPIA OPTICAL PRINCIPAL UNCORRECTED CORRECTED WITH GLASS CORRECTED WITH CONTACT LENS Prescription of appropriate CONCAVE LENSES .
  45. 45. Surgical treatment: 45 Radial keratotomy  Making deep (90 percent thickness radial incision in the peripheral cornea leaving about 4mm central optical zone.  On healing flattens central cornea there by reducing refractive power|(refractive error between -1.5to -6D.
  46. 46. 46 Photorefractive keratectomy  Photoablation of excimer LASER.  Which can accurately ablate corneal tissue to an exact depth with minimal distortion of normal tissues. Myopia is treated by ablating the central anterior corneal surface so that it becomrs flatter.  Approximately 10 micron of ablation corrects 1D of myopia.
  47. 47. 47  LASIK Laser in situ keratomileusis Currently most frequent performed refractive procedure. Can correct myopia upto -10D. Automated microkeratone is used to raise corneal flap. Excimer laser applied to stromal bed and flap again repositioned.
  48. 48. General measures: 48 Balanced diet rich in vitamins and proteins Early management of associated debiliating diseases.
  49. 49. Visual hygienes: 49 to avoid asthenopic symptoms adequate illumination during close work clarity of print should be good to avoid undue ocular fatigue.
  50. 50. Low vision aids: 50 Indicated in patients of progressive myopia with advanced degenerative changes where useful vision cannot be obtained with spectacles and contact lenses.
  51. 51. Prophylaxis 51  genetic counseling for people having pathological myopia, not to marriage with pathological myopic peoples.
  52. 52. PROGNOSIS 52 Simple myopia Prognosis is good. Error usually does not progress beyond 6-8D Stablizes by the age of 21 Pathological myopia: Visual prognosis is always guarded Possibility of progressiove visual loss due to degenerative changes and danger of complications such as retinal detachment should be borne in mind.
  53. 53. References 53 Theory and practice of optics and refraction by AK Khurana Borish’s clinical refraction Internet
  54. 54. 54

×