normal posterior segment anatomy and myopic …normal posterior segment anatomy and myopic...

NORMAL POSTERIOR SEGMENT ANATOMY AND MYOPIC

DEGENERATION

Jessica Watson MD

*some slides/images from Elaine Binkley MD and Drew Carey MD

VITREOUS ANATOMY

MACULA• Define the macula?

• Clinically this is the area within the temporal arcades

• Histologically it is the area with more than one layer of ganglion cell

nuclei

http://eyecenter.dukemedicine.org/eye_center/specialties/macular_degeneration/care_guides/macular_degeneration_frequently_asked_questions

MACULA

• How big is the foveal avascular zone?

• 250-600 microns

http://www.ijo.in/article.asp?issn=0301-4738;year=2011;volume=59;issue=1;spage=9;epage=11;aulast=John

perifovea

parafovea

fovea

Name the structures!


NFL

Ganglion cell layer


NFL

Ganglion cell layer

Inner plexiform layer

NFL

Ganglion cell layer


Inner nuclear layer

NFL

Ganglion cell layer


Inner nuclear layer Outer plexiformlayer (Henle’s layer)

NFL

Ganglion cell layer

Inner plexiformlayer


NFL

Ganglion cell layer



Outer nuclear layer

NFL

Ganglion cell layer


Inner nuclear layer Outer plexiform layer (Henle’s layer)

Outer nuclear layer

Photoreceptors

NFL

Ganglion cell layer


Inner nuclear layer Outer plexiform layer (Henle’s layer)

Outer nuclear layer

Photoreceptors

Retinal pigmented epithelium

RETINA!!!

RETINA!!!

http://users.atw.hu/blp6/BLP6/HTML/common/M9780323045827-008-f002.jpg

Handbook of retinal OCT 1st ed. Duker, Waheed, and Goldman.

What disease may be shown here?


What is wrong with this OCT?

What disease may this be?

RETINAL PIGMENTED EPITHELIUM (RPE)

• RPE

• Single layer of cuboidal epithelial cells

making up the outer layer of the retina

• Between the choriocapillaris and

outer segments of photoreceptors

• 4-6 million RPE cells per eye

• Ratio photoreceptors to RPE cells is

45:1

http://www.scienceofamd.org/learn/

https://medschool.vanderbilt.edu/ophthalmology/labs/cai


•RPE cells are polarized epithelial cells

•Apical side has tight junctions that make up part of the

blood-retina barrier


• What are the major jobs of the RPE? (5)

• 1) Visual pigment regeneration

• 2) Phagocytosis of shed photoreceptor outer segments

• 3) Transport nutrients and ions to

photoreceptors/waste removal

• 4) Absorption scattered light

• 5) Adhesion of the retina

NORMAL ANATOMY

• Temporal retinal fibers follow

an arcuate course to enter the

nerve superiorly and inferiorly

• Papillomacular fibers travel

straight to the nerve from the

fovea

http://www.oculist.net/downaton502/prof/ebook/duanes/pages/v8/v8c021.html

NORMAL ANATOMY

• Müller cells are the glial cells that form the ELM and ILM (not true membranes!)

• ILM is made up of Müller footplates

• Cells are oriented perpendicular to the plane of the RPE in the middle and outer layers but parallel to the retinal surface in the inner layers

• This is why nerve fiber layer hemorrhages are linear and IRH are “dot blots”

https://www.aao.org/eyenet/article/disc-hemorrhages-in-eyes-with-glaucoma

http://www.keywordsdoctor.com/ZG90IGJsb3QgaGVtZQ/

DEGENERATIVE MYOPIA

DEGENERATIVE MYOPIA

• Myopia is a major cause of visual impairment and blindness worldwide

• Myopia most common ocular abnormality in the US (25% of the population).

• High myopia: greater than - 6 D/ 26.5 mm

• Pathologic myopia: greater than -8D/32.5 mm

• Degenerative Myopia =progressive elongation associated with secondary changes

caused by mechanical stretch

• 2% American / possibly high as 10% East Asian

DEGENERATIVE MYOPIA

• Systemic associations with high myopia

• Down syndrome

• Stickler syndrome

• Marfan syndrome

• Prematurity

• Noonan syndrome

• Ehlers–Danlos syndrome

• Pierre–Robin syndrome

PALE TESSELLATED /TIGROID FUNDUS

Due to diffuse attenuation of

the RPE with visibility of large

choroidal vessels

ANOMALOUS OPTIC NERVE HEAD

• May appear unusually

small, large or anomalous

with a “tilted”

conformation.

• Peripapillary chorioretinal

atrophy is very common

• temporal crescent of

thinned or absent RPE

LACQUER CRACKS

• Ruptures in the RPE-Bruchs

membrane-choriocapillaris

complex characterized by fine

irregular yellow lines

crisscrossing the posterior

pole

• ~ 5% of highly myopic eyes

• can be complicated by CNV

PERIPHERAL LACQUER CRACKS

• Due to break in thickened,

calcified Bruch’s

membrane

• Emanate from disc head

• Occur in diseases such as

pseudoxanthoma

elasticum, Ehlers-Danlos

syndrome, sickle cell,

Paget’s disease of bone

ANGIOD STREAK VERSUS LAQUER CRACK

https://maculacenter.com/eye-disease/pseudoxanthoma-elasticum/

SUBRETINAL “COIN” HEMORRHAGES

• May develop from lacquer

cracks in the absence of CNV

FORSTER-FUCHS SPOT

• A raised, circular,

pigmented lesion at the

macula, due to subretinal

or intraretinal RPE

hyperplasia that

presumably develops in

response to a small CNV

that has spontaneously

regressed

DIFFUSE CHORIORETINALATROPHY

• Observed as yellowish-

white, ill-defined

chorioretinal atrophy.

• Typically demonstrates a

thin choroid on OCT

PATCHY CHORIORETINALATROPHY

• Patchy, gyrate areas, of

well-defined chorioretinal

atrophy.

• Different from diffuse

chorioretinal atrophy:

• complete loss of the

choriocapillaris with

visibility of deep

choroidal vessels and

often sclera

• an absolute scotoma

STAPHYLOMA

• A peripapillary or macular

ectasia of the posterior

sclera due to focal thinning

and expansion

• ~ 1/3rd of eyes with

pathological myopia

ANTERIOR STAPHYLOMA

• Grisk for needle injury with

retrobulbar blocks.

• May challenge retinal or

glaucoma surgeries

CNVM

• 5-10% of highly myopic

eyes

• 30% get fellow eye CNVM

• Prognosis better than AMD

• Anti-VEGF therapy

• Lower injection frequency

than AMD

• Risk of RD with injection

higher

MYOPIC CNVM

• Typically seen as a small, flat, greyish

membrane that may have a hyper-

pigmented border if chronic or

recurrent

• Majority of myopic CNV presents with

a “classic” pattern on FA with well

defined early hyperfluoresence

• On OCT, myopic CNV presents as a

highly reflective area contiguous

above the RPE with minimal

subretinal fluidHandbook of retinal OCT 1st ed. Duker, Waheed, and Goldman.

MYOPIC CNVM

Risk factors

• Lacquer cracks

• Patchy atrophy

• Thinning of the

choriocapillaris/choroid

• Fellow eye with CNV (35% in 8

years)

• Note: Can occur without other

features of myopic degeneration

Treatment

• PDT – VIP initial stabilization, but

not improvement. Long-term

chorioretinal atrophy

• Laser – laser scar expansion, high

recurrence

• Surgical incision/translocation

• Anti-VEGF

DIFFERENTIAL FOR MYOPIC CNVM• Myopic macular hemorrhage due to lacquer

crack

• Dome-shaped maculopathy

• RPE Rip

• Myopic macular retinoschisis

• Progressive atrophy

• CSR

• Optic nerve pit

• CNV from other cause

• AMD

• PIC

• Histoplasmosis

• Angioid Streaks

MYOPIC MACULAR RETINOSCHISIS

• Schisis

• Macular retinal detachment

without macular hole

• Macular hole

• Retinal detachment

MACULAR HOLE-ASSOCIATED DETACHMENT

RPE RIP

• As seen here, within a posterior

staphyloma

• Note the well-delineated margin

of atrophy and exposed

choroidal circulation

• Fundus autofluorescence

demonstrates well

progressive atrophy in

pathological myopia

• The top two photographs show

the atrophy and a visual acuity

of 20/50

• Eighteen months later, there

was growth of the staphyloma

and the visual acuity dropped

to 20/100

RHEGMATOGENOUS RETINAL DETACHMENT

• Lifetime risk of RD in high myopia > 20x emmetropia

• Early PVD

• Lattice degeneration

• Asymptomatic atrophic holes

• Myopic macular holes

• Higher risk RD with cataract surgery

• 2.2% in high myopes vs 0.93% general population

GLAUCOMA

• Increased prevalence of

POAG, pigmentary

glaucoma and steroid

responsiveness

• Myopia-related visual field

defects may mimic

glaucoma

• Example: nerves that tilt

inferiorly may have

superior visual field

defects

CASE 1

48 y/o man, asymptomatic- VA

- 20/20 OD- 20/25 OS

- MRx- -11.0 +0.50 x085 OD- -12.0 +0.50 x105 OS

→ Observe, Amsler grid

CASE 2

59 y/o woman with “missing spot” in the vision OS for past month- VA

- 20/20 OD- 20/40 OS

- MRx- -8.25 +1.25 x042 OD- -1075 +1.75 x110 OS

OS INFERIOR PARAFOVEA

OS VERTICAL LINE

OS 1 MONTH AFTER AVASTIN #1: 20/40

OS 1 MONTH AFTER AVASTIN #2: 20/30

→ PRN treatment strategy

THANK YOU!

normal posterior segment anatomy and myopic …normal posterior segment anatomy and myopic...

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