AND ITS LOW VISION MANAGMENT

Indra P SharmaMaster of Clinical Optometry (Year I)

Amity Medical School

ECTOPIA LENTIS

Objective

To have a better understanding about ectopia

lentis with regard to its pathophysiology, etiology,

clinical manifestation and management.

To understand the management of ectopia lentis

with low vision aids

Contents

1. An overview

2. Signs and symptoms

3. Etiology of ectopia lentis

4. Workup and evaluation

5. Treatment

6. Low Vision Management

7. Conculsion

8. Reference

An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

An Overview

Introduction

Ectopia lentis is defined as displacement or malposition

of the crystalline lens of the eye.

1749 - Berryat first reported case of lens dislocation

1856- Stellwag coined the term “ectopia lentis”

Ectopia lentis can be :

1. Subluxation

2. Luxation (dislocated)

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Subluxation

Condition when the

crystalline lens is

partially displaced but

contained within the

lens space.

Few zonular attachment

present

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Dislocation

Also known as luxated

When lens lies completely

outside the lens patellar

fossa, in the anterior

chamber, free-floating in

the vitreous, or directly on

the retina.

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Anatomy of zonules

The lens is suspended in its anatomic position by ciliary zonules (zonules of Zinn or suspensoryligament of Zinn)

Zonules fibers which run from ciliary body and insert into the outer layer of the lens capsule around the equator (1.5 mm anteriorly and 1mm posterior)

Stronger zonules in anterior capsule

Each zonule measures 5 to 30µm in diameter and is composed of bundles of microfibrils

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Pathophysiology

Underlying

pathophysiology -

Disruption or dysfunction of

the zonular fibers of the

lens, regardless of cause

(trauma or heritable

condition)

The degree of zonular

impairment determines the

degree of lens

displacement.Sharma IP

Epidemiology

Frequency

A rare condition.

Incidence in the general population is unknown.

Mortality/Morbidity

Can cause marked visual disturbance, depending the

degree of lens displacement and the underlying etiology

Sex

More common in males.

Age

At any age (At birth or it may manifest late in life)

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Signs and Symptoms

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Symptoms

Distance visual acuity (moderate to severe impairment)

depending on position of lens

1. Fluctuating vision dramatically as the vision may alternate

between phakia and aphakic

2.Progressive movement of the lens- Extreme hyperopic shift or

myopic astigmatism

Poor near vision

Due to loss of accommodative power due to weakened,

stretched or broken zonules

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Contd...

Monocular diplopia

Visual field defects (Due to lens induced secondary

glaucoma)

Source: Sihota R Sood NN, Argarwal He. 1995. Traumatic glaucoma.Acta Ophthalmol Scand

73:252-254.

A 1963 histological study found that crystalline lenses that

were

dislocated anteriorly were associated with glaucoma 77.2% of

the time and that crystalline lenses that were subluxed or

dislocated

posteriorly were associated with glaucoma 87.5% of the time.

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Contd....

Painful red eye (secondary to trauma)

Glare and photophobia

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Etiology of ectopia lentis

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Traumatic dislocation

Traumatic dislocation is most common cause of ectopia

lentis.

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Hereditary ectopia lentis without

systemic manifestations

Single (isolated) ectopia lentis

Autosomal dominant inheritance

Genetic defect located on chromosome

15, causing a dysfunctional zonular

apparatus.

Microspherophakia is common.

Present at birth, can even onset late

Typically, supertemporal displacement

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Ectopia lentis et pupillae

Usually is bilateral and typically autosomal

recessive.

characterized by asymmetric eccentric pupils

that are displaced in the opposite direction of

the lens dislocation (toward the most

dysfunctional zonular fibers).

The irides often appear atrophic with

transillumination defects

Cataracts (common)

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Pupil may be displaced in opposite direction (ectopia lentis et pupillae)Single (isolated) ectopia lentis

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Systemic conditions associated

with ectopia lentis

Marfan syndrome (most frequent cause of

hereditary ectopia lentis)

Homocystinuria (second most common cause of

hereditary ectopia lentis)

Weil-Marchesani syndrome

Sulfite oxidase

Hyperlysinemia

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Marfan syndrome

Transmitted as an autosomal dominant

trait

Prevalence: approx. 5 per 100,000.

Mutations involving the fibrillin gene on

chromosomes 15 and 21 and may relate

to incompetent zonular fibers.

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Systemic association of

Marfan

• Limb-trunk

• disproportion

• Arachnodactyly

• Pectus excavatum

• High-arched palate

• Aortic dilatation,

dissection and

regurgitation

• Mitral valve prolapse

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Ocular manifestation

Superio-temporal

dislocation of a lens in 80%

of cases

Zonules usually intact

Blue sclera

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Contd..

Cornea plana

Axial myopia Lattice degeneration

Angle anomaly and

glaucomaSharma IP

Homocystinuria

It is an inborn error of metabolism.

Most often caused by a deficiency of

cystathionine b-synthetase (the enzyme

that converts homocysteine to

cystathionine).

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Systemic and ocular

manifestation

Malar flush and fine fair hair

Marfanoid habaitus

Increased platelet stickiness

Mental retardation-50%

Inferonasal lens

subluxation -90%

Disintegretation of

zonulesSharma IP

Weil-Marchesani Syndrome

Rare syndrome characterized by skeletal

malformations

The inheritance pattern is not well

understood.

Pupillary block glaucoma is common;

therefore, prophylactic laser peripheral

iridotomies are recommended.Sharma IP

Systemic and ocular

manifestation

Short stature

Short stubby fingers

(brachydactyly)

Mental handicap

Microspherophakia (most

common)

Anterior lens subluxation

(usually)

Angle analomy and glaucomaSharma IP

Sulfite oxidase deficiency

Extremely rare disorder caused by a

defect in sulfur metabolism.

Salient features are:

Progressive CNS abnormalities that

develop within the first year of life

Ectopia lentis.

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Hyperlysinemia

Extremely rare autosomal recessive

enzymatic defect of amino acid

metabolism

Salient features:

Mental retardation and lens dislocation.

Diagnosis is made by demonstration of

increased plasma levels of lysine.

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Primary ocular disorders

associated Congenital glaucoma/buphthalmos

Pseudoexfoliation syndrome

Syphilis/chronic uveitis

Retinitis pigmentosa

Hypermature cataract

Intraocular tumor

High myopia

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Systemic diseases rarely

associated Ehlers-Danlos

syndrome

Crouzon disease

Refsum syndrome

Kniest syndrome

Mandibulofacial

dysostosis

Sturge-Weber

syndrome

Conradi syndrome

Pfaundler

syndrome

Pierre Robin

syndrome

Wildervanck

syndrome

Sprengel deformity

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Workup and evaluation

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Detailed history

History of ocular trauma.

History investigating possible systemic disease

associations.

Cardiovascular disease in Marfan syndrome

Skeletal problems in Marfan syndrome,Weil-Marchesani

syndrome or homocystinuria

Pertinent family history

Consanguinity

Mental retardation

Unexplained deaths at young age

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Ophthalmic evaluation

Visual acuity

Amblyopia is a common cause of decreased vision in congenital ectopia lentis.

External ocular examination

Orbital anatomy for hereditary malformations

(eg, enophthalmos with facial myopathicappearance seen in Marfan syndrome).

Measure corneal diameter (megalocornea in Marfan syndrome).

Strabismus is common (secondary to amblyopia).

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Contd..

Retinoscopy and and keratometry

Careful retinoscopy and refraction is essential, often revealing myopia with astigmatism.

Keratometry may help ascertain degree of corneal astigmatism.

Slit lamp examination

Evaluate lens position, and identify phacodonesis or cataract.

Measure intraocular pressure.

Dilated fundus examination

To rule out retinal detachment

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Laboratory studies

Perform appropriate diagnostic and laboratory

evaluation, if a hereditary condition is suspected

Cardiac evaluation for Marfan syndrome

Check serum and urine levels of homocysteine

or methionine for homocystinuria.

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Imaging studies

A scan

Axial length measurement may be of benefit

(patients with Marfan syndrome have large

globes)

B scan

For any other associated vitrous and retinal

complications

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Treatment

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Refractive management

The key to managing lens subluxation optically is

to

perform two refractions:

1.For that portion of the pupil covered by the

crystalline lens (myopic astigmatism zone) and

2. For that portion of the pupil not covered by

the crystalline lens (highly hyperopic zone).

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Contd...

For moderate to severe subluxation

Option: An aphakic prescription with bifocals

and a pharmacologic dilation

For lens is subluxed out of the visual axis

(bilateral) Best option: An aphakic prescription

Both spectacle and contact lens may be

helpful.

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Medical management

If no, history of trauma, patients may

possess a systemic disease with potentially

deleterious effects; therefore,

comanagement with pediatrician or internist

is essential.

Dietary restriction: partially effective in

homocystinuria.

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Contd...

Treatment of glaucoma is dependent on the etiologic mechanism.

Pupillary block requires laser peripheral iridotomyor iridectomy and raised IOP treated medically.

Prophylactic laser iridotomy in microspherophakia.

Dislodged lens into the AC is initially pharmacological (mydriasis/cycloplegia) in conjunction with ocular massage through a closed lid.

Treatment of a dislocated lens in the vitreous is surgical.Sharma IP

Sugical treatment

1.Nd:YAG laser zonulysis

to displace lens out of visual axis

2.Lesectomy

Lensectomy is technically challenging and are indication in the following:

Lens in the anterior chamber

Lens-induced uveitis

Lens-induced glaucoma

Lenticular opacity with poor visual function

Anisometropia or refractive error not amenable to optical correction (eg, in a child to prevent amblyopia)

Impending dislocation of the lens

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Prevention and prognsis

Deterrence/Prevention

Early diagnosis of ectopia lentis with appropriate optical correction can prevent amblyopia.

Complications

The most common ocular complications include amblyopia, uveitis, glaucoma, and retinal detachment

Prognosis

Depending on the degree of lens dislocation, the age of onset, and its associated secondary complications, most patients do well.

Trauma-associated ectopia lentis – poor visual prognosis

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Low vision management

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Rule of thumb

Provide LVA to help releive the main

symptoms first

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Why do we need it?

To compensate for high hypermetropia or

myopic astigmatism

Distance viewing devices

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High power lenses

High plus spectacle(aspheric lenses)

Aphakic contact

lens(Silsoft/silsoft super plus)

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Roving Ring Scotoma

Circular restriction in the peripheral VF due to

prismatic effect of high plus lenses.

Aspheric lenses

reduces this scotoma

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Telescopes

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Near optical devices

Why is it required?

To compensate for high hyperopia and loss of

accommodation

Preferable near viewing devices

1. Spectacle-mounted Reading Lenses

2. Telemicroscopes

3. Magnifiers

4. Electronic Devices- CCTV

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Spetacle mounted reading glasses

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Telemicroscope

Eyeglass

mounted

microscopes can

be

made to focus at

any

working distance.Sharma IP

Magnifiers

Illuminated and non-illuminated

Hand held and stand magnifiers

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Electronic magnification

devices

Head mounted video

display systems

CCTV

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Visual field enhancing

devices

Reverse telescope

To compensate for VF

defects due to secondary

Glaucoma.

Prisms

Mirrors

Reverse Telescope system

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Non-optical aids

Relative size and larger assistive devices

Glare, contrast, and lighting control devices

Handwriting and written communication devices

Medical management devices

Orientation and mobility management techniques and devices

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Relative size and larger assistive

devices

Large print

Books, magazines, newspaper, dictionaries, thesauri, atlas, cookbooks, encyclopedias, bibles

Photocopy machines ( e.g. A4 size to A3 size)

Computer with large prints font

Computer software program

Large print typewriters

Others Telephone dial, bank checks, watches, clocks, calculators etc

Games like cross word puzzles, playing cards, chess checkers, bingo etc.

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Magic 8.0 Large print telephones

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Large print

calculator

Playing cards

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Glare, contrast, and lighting

control devices

Aphakia allows for increased transmission of UV

radiation

Shades

Tennis shades, caps, hats, side-shields, visors

Filters

NoIR and CPF lenses

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Sunglasses/ photochromatic lenses to reduce

illumination levels

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Typoscopes – a reading guide cutoff glare

Glare cutter ( 390-410nm)-cuts 100% UVB, 99% UVA

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Diplopia eliminating devices

Stenopeic slit

Aperture control contact lens

Pinhole lenses

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Color and contrast

adjustments

Environmental modification Painted edges of Staircase

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Contrast in kitchen

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Hand writing and written

communication Signature guide

Check guides

Reading guide

Large prints

Bold felt-tip pens

Bold line paper

Large print typewriters

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Medical management devices

Monitoring blood glucose

Large print syringe

Syringe with magnifiers ( optical device)

Preset dosage

Pre-filled syringes- filled with clicking sounds

Monitoring blood pressure Readout sphygmomanometers for hearing problems

Monitoring temperatures Large readout thermometers and talking thermometer

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Talking colour detector

IPS

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Counselling

If a hereditary condition is discovered,

appropriate genetic counseling recommended.

All relatives with potential risk should be

examined.

Advised against playing contact sports or doing

physically strenous activities.

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference

Conclusion

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Take home message

Managing patients with ectopia lentis including refraction is usually difficult and needs expertise to manage them well.

As most patients with ectopia lentis are syndromic, co-management with other specialist is essential.

While managing patient with low vision we need to looks at various cause and other ocular association like glaucoma, retinal detachment and amblyopia.

An optometrist needs to understand the need of the patient and prescribe according.

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An overview

Signs and

Symptoms

Etiology of

ectopia lentis

Workup and

evaluation

Treatment

Low Vision

Management

Conculsion

Reference Reference

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ReferenceBooks

Jonathan A Jackson, Low Vision Mannual,2007, Butterworth Heineman Elsevier.

William J Benjamin,2006, Borish’s Clinical Refraction, Butterworth Heineman Elsevier. 20: 816-829

Lighthouse International, The Lighthouse Clinician’s Guide to Low Vision Practice

Brilliant Richard L, 1999, Essentials of Low vision Practice,Butterworth Heineman Elsevier. 6.8.9.10

Websites

www.emedicine.medscape.com

www.rootatlas.com

en.wikipedia.org

www.google.com/imghp

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Tashi Delek

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