Pathological Myopia

1
Pathological Myopia

• Presented by
• Dr. Mohammad Abdullah Bawtag

Sankara Nethralay a Chennai, India 2014
2
(No Transcript)
3
History of Pathological Myopia
4
Myopia- New Latin was derived from the
original Greek word muopia contracting or
closing the eye.
- 138201 Galen was the first to use the term
myopia
PM- 1988 Takashi Tokoro Definition of
pathologic myopia
Staphyloma - is a pathognomic feature of PM
- 1801 Antonio Scarpa First anatomical
description of posterior staphyloma, but did not
make the link to myopia
- 1856 Carl Ferdinand von Arlt First connected
staphyloma and myopic refraction

• - 1977 Brian J. Curtin Classification scheme
  for staphyloma

5
Terminologies of Pathological Myopia
6
Pathological myopia
Degenerative myopia
Malignant myopia
High degree myopia
Progressive myopia
Magna myopia
7
Definitions of Pathological Myopia
8
Clinically- refractive error gt -6 D.
Duke-Elder - Myopia with degenerative changes
especially in the post. segment.
Tokoro - Myopia caused by pathological axial
elongation.
A more specific - Myopic retinopathy, refers to
the degeneration of chorioretinal tissue ass.
with axial elongation of the eye.
9
Prevalence of Pathological Myopia
10
Country Country
Myopia Some Asian countries 7090 Industrialized -West 1025
Myopia Taiwan 84 Africa 1020
Myopia Industrialized - East 6080 India 6.9
Myopia Europe and the US 3040

PM Asian 921 Most countries 14
PM Spain 9.6 USA 2
PM Singapore 9.1 Bangladeshi 1.8
PM Japan 8 Czechoslovakia 1
PM Northern China 4.1 Egypt 0.2
PM
High myopia affects 27-33 of all myopic eyes in Asia. High myopia affects 27-33 of all myopic eyes in Asia. High myopia affects 27-33 of all myopic eyes in Asia. High myopia affects 27-33 of all myopic eyes in Asia.
11
Interesting facts
Lengthening of the post. segment of the eye
commences only during the period of active
growth. The eye and the brain show precocious
growth at the age of 4 years the brain is 84
and the eye 78 and the rest of the body 21.
After this, both the eye and the brain increase
slowly while the body grows more rapidly.
However, when axial myopia continues to progress,
it is interpreted as a precocious growth which
has failed to get arrested.!!!!!!!!!! We do
not as yet know what this influence is.
12
Pathogenesis of Pathological Myopia
13
Etiology of Myopia is as diverse and
controversial as one can imagine. Everything in
medicine has been blamed as a cause of Myopia.
Two types of theories are put forward
1) Mechanical and Environmental
2) Biological
14
Mechanical theories - distension of normal
sclera - Increased IOP caused by the action of
EOMs or IOMs or by insidious chronic glaucoma.
Others theories weakening of the sclera -
venous congestion, inflammation or dietary
deficiency.
15
Classification of Myopia
16
Type of Class. Classes of Myopia
Cause Axil Myopia Refractive Myopia ( Curvature Index )
Clinical Entity Simple myopia Nocturnal myopia Pseudomyopia Degenerative myopia Induced myopia
Degree Low myopia (lt-3.00 D) Medium myopia (-3.00 D - -6.00 D) High myopia (gt-6.00 D)
Age of Onset Congenital myopia (present at birth and persisting through infancy) Youth-onset myopia (lt20 years of age) Early adult-onset myopia (20-40 years of age) Late adult-onset myopia (gt40 years of age)
17
High Myopia is classified in a simple manner
as i) Simple
ii) pathological
Simple Myopia - not progressive, good vision-
optical correction.
Pathological Myopia - changes in the posterior
segment, lengthening of AP axis of the globe.
18
Risk factors
19
Risk factors Description
Race ethnicity Asians
Age Middle aged (working life) or younger
Gender Female
Social group Children(Asian) professional working adults
Geography Industrialised/developed nations
Lifestyle Time spent outdoors
Education High level of education/academic achievement
Occupation Near work indoors (e.g. lawyers, physicians, microscopists and editors)
Familial inheritance (parental refraction) Genetic
20
Genetic factors
21
Family studies and twin studies have revealed the
heritability of myopia since the 1960s. In
familial studies and twin studies, linkage
analysis using microsatellite markers has
identified 19 loci for myopia MYP1 to MYP19.
Common Myopia
AD High Myopia
AR High Myopia
X-Linked High Myopia
MYP7 MYP8 MYP9 MYP10 MYP14 MYP17
MYP1 MYP13
MYP2 MYP3 MYP4 MYP5 MYP11 MYP12 MYP15 MYP16 MYP17
MYP19
MYP18
22
Manifestations of Pathological Myopia
Anatomical Manifestations
Functional Manifestations
Ocular Manifestations
23
Anatomical Manifestations
Corneal astigmatism
Tilted disc
Deep AC
Peripapillary detachment in PM
Angle iris processes
Temporal crescent or halo atrophy
Zonular dehiscences
Macular lacquer cracks
Vitreous syneresis
Pigment epithelial thinning
Lattice retinal degeneration
Choroidal attenuation
Scleral expansion and thinning
Foveal retinoschisis
? Ocular rigidity
Post. staphyloma
? AL
24
Functional Manifestations
Image minification
Anisometropic amblyopia
Subnormal visual acuity
Visual field defects
Impaired dark adaptation
Abnormal color discrimination
Suboptimal binocularity
25
Ocular Manifestations

• Strabismusexophoria/exotropia
• Cataract.
• Glaucoma.. pigmentary / normal-tension glaucoma
• Tigroid, or blond fundus, with choroidal visible
  underneath
• Tilted optic nerve with peripapillary atrophy
• Peripapillary detachment
• Chororetinal atrophy
• PVD
• RD
• Lacquer cracks
• Lattice degeneration (spontaneous breaks in
  Bruch's membrane)
• Cobblestone degeneration
• Fuch's spot (RPE hyperplasia in response to CNV)
• Scleral thinning
• Peripheral retinal holes
• Macular holes causing RD
• CNV

26
Complications of Pathological Myopia
This review aims to provide an overview on some
of the important complications associated with PM.
Vitreous degeneration
Myopic foveoschisis Macular hole
Peripheral retinal degenerations RRD
Lacquer cracks
CNV in PM
Post. Staphyloma
27
Vitreous degeneration

• Syneresis
• Vitreous liquefaction, fibril aggregation
  condensation
• Associated with floaters
• Caused by myopia, senescence, trauma,
  inflammations, hereditary causes
• PVD

28
Liquefaction of the vitreous gel
Hole in the posterior hyaloid membrane
Fluid tru defect into retrohyaloid space
Vitreous gel collapses synchytic fluid in space
Detachment of posterior vitreous from ILM
Acute PVD
29

• PVD with gel collapse
• Without vitreous hage, 4 develop retinal breaks
• With vitreous hage, 20 develop breaks
• PVD without gel collapse
• Associated with future retinal hole or vitreous
  hage
• Scaffold for proliferative new vessels

30
Flow chart illustrating the natural history of an
acute PVD
31
Ultrasound picture showing PVD. Note that the
vitreous is still attached at the optic disc and
the ora serrata.
32
Vitreous changes in PM

• Vitreous liquefaction
• Early PVD
• Presence of CPVD
• Larger posterior precortical vitreous pocket
• Residual posterior cortex in CPVD

Years PM control
20- 39 27.8
40-59 43 8
60 - 79 91 60
33
Myopic Foveoschisis

• Prevalence 9 to 34
• Pathogenesis
• 1. Attachment of Contracted vitreous cortex to
  retinal surface
• 2. ERM
• 3. Retinal vascular traction
• 4. Rigidity of ILM
• 5. Progression of posterior staphyloma

34

• Natural history
• Varied course with diverse visual outcomes-
  stable to development of macular holes
• Eyes with anterior traction had worst
  prognosis
• Progressive disease with poor outcomes
• Treatment
• PPVILM peeling(traditional/foveal sparing) /-
  tamponade useful to relieve internal surface
  anterior traction
• Scleral buckling Addresses disparity between
  retina and elongated sclera
• Suprachoroidal buckling hyaluronic acid
  injected through a catheter into suprachoroidal
  space in the area of staphyloma to indent choroid
• Complications
• Choroidal hemorrhage and hyperpigmentation around
  area of indentation.

35
Macular hole
Myopic macular hole may occur, but the exact
mechanism is unknown. Whether attenuation of the
neural retina and its supportive pigment
epithelium and choroid are responsible is
speculative.
36
Various surgical procedures have been performed
for macular hole with or without RD and they
include

• PPV with gas or silicone oil tamponade

• Macular buckling

• Scleral shortening surgeries.

37
Myopic macular chorioretinopathy

• DEF is a rare, genetic eye disorder that
  causes vision loss.
• Grading(shih et al)
• MO - Normal post pole
• M1 - Tesselation choroidal pallor
• M2 - M1post staphyloma
• M3 - M2lacker cracks
• M4 - M3 focal deep choroidal atrophy
• M5 - M4geographic atrophy, CNV
• M3gt- myopic maculopathy

38
Peripheral retinal degenerations RRD

• Lattice degeneration is a common retinal
  degeneration.
• 1. Epidemiology
• 8-10 of general population (but 20-40 of RD)
• More commonly in moderate myopes and is the most
  important degeneration directly related to RD
• Location Commonly -temporal superiorly fundus
  Between equator and ora serrata
• 2. Pathology
• Discontinuity of internal limiting membrane
• Atrophy of inner layers of retina
• Overlying pocket of liquefied vitreous
• Adherence of vitreous to edge of lattice
  (posterior edge)
• Sclerosis of retinal vessels

39
(No Transcript)
40
Lattice degeneration - predispose to RRD Retinal
tears - posterior and lateral margins of the
lattice degeneration Role of prophylactic Laser
photocoagulation History of RD in the fellow
eye Family history of RD Prior to ocular
surgeries Symptomatic pt
41
In eyes with RD, laser photocoagulation alone is
insufficient to treat the condition and V-R
surgery is required. Surgical modalities for RRD
- pneumatic retinopexy, SB surgery with
cryopexy, and PPVBBEL C3F8/ SIO.
CLINICAL PEARLS Lattice degeneration both with
and without atrophic holes is generally benign
and does not require prophylactic treatment, as
the complications of treatment are more severe
than the natural history of the untreated
condition.
42
Myopic RD

• Incidence of RD in general population range
  between 0.005 and 0.01 .
• RD occurs far more frequently in patients with
  myopia.
• Disease Case-control study Group found that
  subjects with sepherical equivalent refractive
  error of -1 to -3 diopters had a fourfold greater
  risk of RD then a nonmyopic individual.
• For refractive errors greater than -3 diopters
  the risk was tenfold greater
• More than half of nontraumatic RRD occurs in
  myopic eyes.

43
(No Transcript)
44
CNV in Pathological Myopia
Among various lesions associated with high
myopia, macular CNV is one of the most vision
threatening complications. It develops in
around 5 to 10 of eyes with high myopia and is
the commonest cause of CNV in young individuals
and accounts for around 60 of CNV in young
patients aged 50 years or younger.
Macular hage ass. with CNV in high myopia
45

• Develops from laquer cracks.
• Smaller, less exudation.
• - Type 1 (severe myopic degeneration)-
  Leakage does not extend beyond initial CNVM
  border- Quiescent scar.
• - Type2( Minimal degeneration)- Leakage
  beyond CNVM borders- Fibrovascular scarring.

46
The mechanism of CNV formation in myopic CNV is
still unclear.

• A possible explanation includes, certainly, the
  induced hypoxia in the outer retina, which is a
  large source of VEGF secretion. Chorioretinal
  stretching, lacquer crack formation, choroidal
  thinning, choroidal flow disturbance with reduced
  flow, choroidal filling delay, RPE and overlying
  retina atrophy, loss of photoreceptors, all of
  them can be involved in growth factor release and
  myopic CNV formation. The role of each of these
  features and the interconnections between them
  remain unclear

47
Treatment of myopic CNV
More recently, the use of anti-VEGF agents
The most commonly used currently is PDT with
verteporfin.
A combination therapy of PDT with anti-VEGF
agents appears efficacious in the treatment of
eyes with CNV secondary to pathological myopia,
and may afford better visual outcomes as compared
to PDT monotherapy

• Laser photocoagulation of . no longer performed.
• Other treatment modalities
• Submacular surgery
• Macular translocation surgery

48
Features of choroid in PM

• Stretched choroid without additional vasculature
• Thinner choroid
• Choriocapillaries and larger ch.vessel have
  decreased lumen
• Choriocapillaries have loss of fenestrations
• Increased number of vortex veins(gt4)
• Posterior vortex veins(ciliovaginal veins)
• Reduction of choroidal thickness is proportional
  to age and refractive status
• Per diopter myopia caused 8µm reduction in
  choroidal thickness
• Per decade causing 12-15µm reduction in choroidal
  thickness
• Intrachoroidal cavitation the expansion of
  distance between inner wall of sclera and
  posterior surface of bruchs membrane
• Attenuated choroid to absent choroid myopic
  chorioretinal atrophy

49
Lacquer cracks
Spontaneous ruptures in the Bruch's membrane
. Small hages may develop within the lacquer
cracks. Lacquer cracks predispose - macular
CNV Small ingrowth of fibrovascular tissue may
also give rise to small elevated pigmented
circular lesions and are known as Fuchs spots.
50
Post. Staphyloma
51
post. staphyloma (ectasia) Equatorial
staphyloma with scleral dehiscence - STQ.
Visual loss is most often due to macular
involvement of a post. pole staphyloma.
52
Curtin classified the staphylomas into ten
categories. The first five were simpler
configurations, while the last five were either
more intricate in their configuration
53
Tesselated Fundus

• Hypoplasia of the RPE following axial elongation
  reduces the pigment, allowing the choroidal
  vessels to be seen.
• Commonly seen in elderly or brunette patients.
• May not be associated with any clinical
  significance

54
References
55

• Ohno-Matsui K, Yoshida T, Futagami S, Yasuzumi K,
  Shimada N, Kojima A, et al. Patchy atrophy and
  lacquer cracks predispose to the development of
  CNV in PM. Br J Ophthalmol 2003 87 570-573.
• Cheung BT, Lai YY, Yuen CY, et al. Results of
  high-density silicone oil as a tamponade agent in
  macular hole RD in patients with high myopia. Br
  J Ophthalmol 200791719-721.
• Chinese Medical Journal 2013126(8)1578-1583
• Bhatt N S, Diamond J G, Jalali S, Das T.
  Choroidal neovascular membrane. Indian J
  Ophthalmol 19984667-80
• Hamelin N, Glacet-Bernard A, Brindeau C, et al.
  Surgical treatment of subfoveal
  neovascularization in myopia macular
  translocation vs surgical removal. Am J
  Ophthalmol 2002133530-6.
• Flower RW. Expanded hypothesis on the mechanism
  of photodynamic therapy action on CNV. Retina
  199919365-69.
• Albert Jakobiec,Principles and Practice of
  Ophthalmology, Volume 2, Chapter 154 PM P
  2023-2027, 3rd ed 2008.
• Pathological Myopia, Richard F. Spaide, Kyoko
  Ohno-Matsui, Lawrence A. Yannuzzi Editors
• Kyoko Ohno Matstui MD, Phd, Muka Moriyama MD,
  PhD Staphyloma II Analyses of Morphological
  Features of Posterior Staphyloma in Pathologic
  Myopia Analyzed by a Combination of Wide-View
  Fundus Observation and 3D MRI Analyses
  Pathological Myopia 2014, pp 177-185

56

• Pukhrai Rishi, et al ..Photodynamic
  monotherapy or combination treatment with
  intravitreal triamcinolone acetonide, bevacizumab
  or ranibizumab for choroidal neovascularization
  associated with pathological myopia.. 2011

57
(No Transcript)
58
Thanks