Presented by:

Dr. Mohammad Abdullah Bawtag

Sankara Nethralay a– Chennai, India

2014

History of Pathological Myopia

- 1977 Brian J. Curtin Classification scheme for staphyloma

Myopia- New Latin …… was derived from the original Greek word “mŭopia” …

contracting or closing the eye.

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

- 138–201 Galen was the first to use the term myopia

Terminologies of Pathological Myopia

Pathological myopia

Degenerative myopia

Malignant myopia

High degree myopia

Progressive myopia

Magna myopia

Definitions of Pathological Myopia

Clinically- refractive error > -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.

Prevalence of Pathological Myopia

Country % Country %

Myopia

Some Asian countries 70–90% Industrialized -West 10%–25%

Taiwan 84% Africa 10–20%

Industrialized - East 60%–80% India 6.9%

Europe and the US 30–40%

PM

Asian 9–21% Most countries 1–4%

Spain 9.6% USA 2%

Singapore 9.1% Bangladeshi 1.8%

Japan 8% Czechoslovakia 1%

Northern China 4.1% Egypt 0.2%

High myopia affects 27%-33% of all myopic eyes in Asia.

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%.

Interesting facts

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.

Pathogenesis of Pathological Myopia

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

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.

Classification of Myopia

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 (<-3.00 D)

Medium myopia (-3.00 D - -6.00 D)

High myopia (>-6.00 D)

Age of Onset Congenital myopia

(present at birth and persisting through infancy)

Youth-onset myopia

(<20 years of age)

Early adult-onset myopia

(20-40 years of age)

Late adult-onset myopia

(>40 years of age)

Simple Myopia - not progressive, good vision- optical correction.

Pathological Myopia - changes in the posterior segment,

lengthening of AP axis of the globe.

High Myopia is classified in a simple manner as:

i) Simple ii) pathological

Risk factors

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

Genetic factors

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.

AD High Myopia AR High Myopia X-Linked High Myopia Common Myopia

MYP1

MYP13MYP18MYP2

MYP3

MYP4

MYP5

MYP11

MYP12

MYP15

MYP16

MYP17

MYP19

MYP7

MYP8

MYP9

MYP10

MYP14

MYP17

Manifestations of Pathological Myopia

Anatomical Manifestations

Functional Manifestations

Ocular Manifestations

Anatomical Manifestations

Corneal astigmatism

Deep AC

Angle iris processes

Zonular dehiscences

Vitreous syneresis

Lattice retinal degeneration

Scleral expansion and thinning

↓ Ocular rigidity

↑ AL

Post. staphyloma

Tilted disc

Temporal crescent or halo atrophy

Macular lacquer cracks

Pigment epithelial thinning

Choroidal attenuation

Peripapillary detachment in PM

Foveal retinoschisis

Functional Manifestations

Suboptimal binocularity

Image minification

Anisometropic amblyopia

Subnormal visual acuity

Visual field defects

Impaired dark adaptation

Abnormal color discrimination

Ocular Manifestations

-Strabismus：exophoria／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

Complications of Pathological Myopia

This review aims to provide an overview on some of the important complications associated with PM.

Peripheral retinal

degenerations & RRD

Myopic foveoschisis &

Macular hole

Lacquer cracksCNV in PM

Vitreous degeneration

Post. Staphyloma

Vitreous degeneration

Syneresis

Vitreous liquefaction, fibril aggregation & condensation

Associated with floaters

Caused by myopia, senescence, trauma, inflammations,

hereditary causes

PVD

Liquefaction of the vitreous gel

Hole in the posterior hyaloid membrane

Fluid tru defect into retrohyaloid space

Vitreous gel collapsessynchytic fluid in space

Detachment of posterior vitreous from ILM Acute PVD

•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

Flow chart illustrating the natural history of an acute PVD

Symptomatic PVD

Approx 10-15 %

Retinal breaks at first

assessment

Approx 90 %

uncomlicated at first

assessment

High risk

break

Low risk

break

Low risk of

detachment

Approx 98 %

uncomplicated

At 4-6 weeks

1.5-3.4%

Retinal breaks

At 4-6 weeks

Detachment

In 33-46%

Within 6

weeks

Ultrasound picture showing PVD. Note that the vitreous is still attached at the optic disc and the ora serrata.

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%

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

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:

PPV+ILM 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.

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.

Macular hole

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.

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 - M1+post staphyloma

M3 - M2+lacker cracks

M4 - M3+ focal deep choroidal atrophy

M5 - M4+geographic atrophy, CNV

M3>- myopic maculopathy

“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

Peripheral retinal degenerations & RRD

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

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 PPV+BB+EL+ C3F8/ SIO.

CLINICAL PEARLSLattice degeneration both with and without atrophic holes is generallybenign and does not require prophylactic treatment, as the complications oftreatment are more severe than the natural history of the untreatedcondition.

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 withsepherical equivalent refractive error of -1 to -3 dioptershad a fourfold greater risk of RD then a nonmyopicindividual.

• For refractive errors greater than -3 diopters the risk wastenfold greater

More than half of nontraumatic RRD occurs in myopiceyes.

Syneresis of the central vitreous

Traction caused by spontaneous

or PVD

RETINAL TEAR

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

- 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.

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

The mechanism of CNV formation in myopic CNV is still

unclear.

•Laser photocoagulation of …. no longer performed.

• Other treatment modalities

- Submacular surgery

- Macular translocation surgery

The most commonly used currently is PDT with

verteporfin.

More recently, the use of anti-VEGF agents

A combination therapy of PDT with anti-VEGFagents appears efficacious in the treatment of eyeswith CNV secondary to pathological myopia, andmay afford better visual outcomes as compared toPDT monotherapy

Treatment of myopic CNV

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(>4)

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 bruch’s membrane

Attenuated choroid to absent choroid – myopic chorioretinal atrophy

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.

Post. Staphyloma

post. staphyloma (ectasia)

Equatorial staphyloma with scleral dehiscence - STQ.

Visual loss is most often due to macular involvement of a post. pole

staphyloma.

Curtin classified the staphylomas into ten categories. The first five were simpler

configurations, while the last five were either more intricate in their configuration

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

References

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Cheung BT, Lai YY, Yuen CY, et al. Results of high-density silicone oil as a tamponade agent in

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Hamelin N, Glacet-Bernard A, Brindeau C, et al. Surgical treatment of subfoveal

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Morphological Features of Posterior Staphyloma in Pathologic Myopia Analyzed by a

Combination of Wide-View Fundus Observation and 3D MRI Analyses Pathological Myopia

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Pukhrai Rishi, … et al …..Photodynamic monotherapy or combination treatment with intravitreal triamcinolone acetonide, bevacizumab or ranibizumab for choroidal

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