10-subluxated-lens.ppt

lens subluxation

1. SUBLUXATED LENS
Dr Rekha Gyanchand
Consultant
Lions Eye Hospital,Bangalore

2. ANATOMY OF SUBLUXATION
The lens is suspended in its anatomic position by ciliary
zonules (zonules of Zinn or suspensory ligament of Zinn)
Zonules fibers which run from ciliary body and fuse into the
outer layer of the lens capsule around the equatorial zone.
The bundles that insert into the anterior capsule are
stronger than those that insert in the posterior capsule.
The insertion of zonules extends 1.5 mm anterior to the
equator and 1mm posterior .
Each zonule measures 5 to 30µm in diameter and is
composed of bundles of microfibrils.
Biochemicallythey are composed of fibrillin, a protein
product of the gene linked to Marfan’s syndrome.

3. Definition -Subluxation of lens
Malposition of the crystalline lens when it is
partially displaced but contained within the
lens space .Few zonular attachments
present.
 Dislocation of lens
Lens lies completely outside the lens
patellar fossa, in the anterior chamber, free-
floating in the vitreous, or directly on the
retina

4. ETIOLOGY
CONGENITAL
Isolated ectopia lentis
Ectopia lentis et pupillae
Hereditary ectopia lentis with
systemic manifestations (Marfens
etc)
ACQUIRED
Trauma-Common
WEAK ZONULES
Hypermature cataract
Chronic cyclitis , uveitis
RP ,RD
Syphilis
Buphthalmos
Severe or pathological
myopia
Ciliary body tumor

5. Congenital -Single (isolated) ectopia
lentis
Autosomal dominant inheritance
Birth, late onset has been described
Dysfunctional zonular apparatus
Superotemporal displacement

6. Congenital -Symmetric eccentric pupils
Autosomal recessive
Bilateral
Irides often appear, Atrophic &
Transillumination defects
Dysfunctional zonular fibers
Displaced in the opposite direction of the
lens subluxation .

7. Congenital-Hereditary ectopia lentis with systemic
manifestations
Systemic disorders
Marfan’s syndrome
Homocystinuria
Weil Marchesani syndrome
Reiger’s anomaly
Ehler Danlos syndrome
Hyperlysinemia
Sulfite oxidase deficiency
Sturge Weber’s syndrome
Craniosynostosis

8. Marfan Syndrome-Heritable Ectopia
lentis
Lens subluxated-75%
bilateral, symmetrical, supertemporal
Axial myopia ,Increase incidence of RD

9. Homocystinuria-In born metabolic
error
Inborn error of metabolism
near absence of cystathionine
b-synthetase(the enzyme that
converts homocysteineto
cystathionine)
Deficient zonularintegrity
secondary to the enzymatic
defect
Thromboembolicevents
constitute the major threat to
survival, especially following
general anesthesia.
Fair skin with coarse hair
Osteoporosis
MR (50 %)
Seizure disorder
Marfanoid habitus
Poor circulation
Lens subluxated –90%
Bilateral,
Symmetrical Inferonasal,

10. Weil Marchesani Syndrome
skeletal malformations
short stature
brachycephaly
limited joint mobility
well-developed muscular
appearance
Ectopia lentis
Microspherophakia
lenticular myopia
High incidence of lens
subluxation occurs
inferiorly,often
progressing to
complete dislocation.
Pupillary block
glaucoma is common;
therefore, prophylactic
laser peripheral
iridotomies are
recommended.

11. ASSOCIATED OCULAR ANOMALIES
Congenital glaucoma/buphthalmos
Pseudoexfoliation syndrome
Chronic uveitis
Retinitis pigmentosa
Megalocornea
Aniridia
Hypermature cataract
High myopia

12. Others ..
Sulfite oxidase deficiency
Extremely rare
Defect in sulfur
metabolism.
Progressive CNS
abnormalities -within
the first year of life in
concert with ectopia
lentis
Hyperlysinemia
Autosomal recessive
Enzymatic defect of
amino acid
metabolism
Mental retardation
Lens dislocation.
Diagnosis: increased
plasma levels of
lysine.

13. Cause for decrease VA
•Fluctuating vision dramatically as the vision may
alternate between phakia and aphakic
•Progressive movement of the lens -Extreme
hyperopic or myopic shift , astigmatism
•Monocular diplopia
•Poor near vision (loss of accommodative power)

14. COMPLICATION
Pupillary block glaucoma
Forwards displacement-Endothelial
damage,sec.Ac angle closure

15. WORK –UP History
History of ocular trauma.
Systemic history investigating systemic disease .
Cardiovascular disease (eg, Marfan syndrome)
Skeletal problems
Marfan syndrome
Weil-Marchesani syndrome
Homocystinuria
Family history
Consanguinity
Mental retardation
Unexplained deaths at young age (eg, autosomal recessive
conditions, including homocystinuria, hyperlysinemia, ectopia
lentis et pupillae, or sulfite oxidase deficiency)

16. Ocular Examination Attention to orbital anatomy : evaluate for
hereditary malformations (eg, enophthalmos
with facial myopathic appearance seen in
patients with Marfan syndrome).
Measure corneal diameter
(megalocornea is associated with Marfan
syndrome).
Strabismus (amblyopia).
Careful retinoscopy and refraction is essential,
often revealing myopia with astigmatism.
Keratometry may help ascertain degree of
corneal astigmatism.

17. Ocular Evaluation
VANear /distant BCVA, Best vision with aphakic correction
Gonioscopynote any developmental defects, pseudoexfoliative material and deformities
secondary to trauma or as a sequlae to subluxation.
Fundus examinationis done to look for lattice degeneration, cyclitic membranes, retinal
detachment or posttraumatic pathology. Retinal detachments occur in 10% eyes with Marfan’s
syndrome and Homocystinuria.
Bscan ultrasonographyis indicated in opaque ocular media.
Presence if any of uveitis, glaucoma, corneal edema and amblyopia should also be
ascertained
Ultrasound biomicroscopy /anterior segment OCT, are especially useful for zonular and
angle assessment in patients where the pupil fails to dilate
A-ScanAxial length measurement
Causes of glaucoma in ectopia lentis
pupillary block , phacoanaphylaxis or phacolytic , posttraumatic angle recession
poorly developed angle structures , lens in the anterior chamber.

18. Preoperative Evaluation
Evaluate lens position, and identify phacodonesis or cataract
Exact degree of zonular loss
Vitreous in the anterior chamber .
An inferior subluxation often indicates 360 degrees of zonular
insufficiency combined with the effect of gravity.

19. OTHER INVESTIGATIONS
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).
Imaging Studies
Echography

20. Conservative Measures
For stable induced refractive errors, visual
correction with glasses or contact lenses
may be an option.
Partially occluding contact lenses
Cycloplegics/miotics
Enlarge aphakic portion
-Nd YAG zonulolysis
-Optical iridectomy

21. Indication for Lensectomy
Lens in the anterior chamber
Lens-induced uveitis
Lens-induced glaucoma
Lenticular opacity with poor visual function
Cataract
Anisometropia or unstable refractive error
Impending dislocation of the lens : large
zonular dialysis

22. Dos and Don’ts -Cataract Incisions
Preferably away from area of zonular
weakness
Use high molecular weight viscoelastic
Capsulorrhexis should be initiated in an area
remote from the dialysis ,Capsulorrhexis is
more easily performed with forceps than with
cystitome & should be made "off-center" in
an eye with significant lens subluxation

23. CAPSULAR TENSION RINGS
Morcher CTR
Alcon CTR
Cionni CTR
CTR Ringmorcher

24. Choice of surgical procedure
Degree of Zonular dehicense Procedure chosen
 Superiorupto 4 clock hours
1
st
choice: CTR with IOL implantation
2 st choice: IOL implantation with haptic being used to stretch
the bag
Inferior upto 3 clock hours CTR with IOL implantation
Anywhere> 3 to 6 clock hours Modified CTR with single loop
Anywhere >6 to >9 clock hours Modified CTRwith double loop
with IOL implantation
9 or more clock hours /generalized weakness of
zonulesIntracapsular cataract extraction with scleral fixated
IOL/Iris fixated IOL/anterior chamber IOL

25. Surgical Technique
Anterior limbal approach
ICCE
ECCE
SICS
PHACO
Posterior pars plana approach
Vitrectomy : soft lens
Phacofragmentome

26. Surgical tips
Good sized rhexis err on larger side …
they develop capsule contraction
Use a chop or supracapsular technique,
because it allows to raise the nucleus
above the capsule, putting less stress on
the zonules.
Another technique is viscoelevation.

27. Counselling
Patient Education
Genetic counselling
Follow up with physician to rule out life-
threatening disorders.
Safety glasses are advocated when risk of
eye injury is possible.

28. Thank You