What is the average refractive power of the lens ? 15 D
A radius of curvature of the cornea is 8 mm and refractive indices are 1 (air) and 1.33 (cornea, aqueous and vitreous). An aphakic eye has an anterior focal distance of 23 mm, and the posterior focal distance of 31 mm.
The management depends on the underlying cause
Corectopia: distorted pupil
The anterior chamber may contain cells, flare or even hyphaema.
Common Cases: Lens and Glaucoma
Dr. Riyad BanayotDr. Riyad Banayot
Hypermature cataract. Note the wrinkling of the anterior capsule, the
lens has liquefied and leaks out of the capsule.
A morgagnian cataract. The cortex has turned into milky liquid and the
nucleus is displaced inferiorly.
A rosette cataract. This is seen in blunt trauma.
Look for other signs in the posterior segment such as choroidal tear or RD
A lamellar cataract. There are opacities at various levels of the fetal
nucleus. It is the most common type of congenital cataract.
A droplet cataract seen in a patient with galactosaemia.
In a young patient
With bilateral cataract. Look for:
Atopic dermatitis (examine the face)
Diabetic mellitus (examine fundus for DR)
Retinitis pigmentosa (examine fundi for
Myotonic dystrophy (note the typical facies of
frontal balding, bilateral ptosis and delayed
With unilateral cataract. Look for:
Fuch's heterochromic uveitis
There is a significant shift in the fluid
content of the normal lens probably
related to the accumulation of sorbitol
inside the diabetic lens.
The result is:
Rapid formation of subcapsular granular
cataract also called the snowstorm cataract.
Nuclear sclerotic cataract.
The increased density of the nucleus
increases the refractive index, and as a
result the patient develop myopia.
As a result, patients who previously
needed plus lenses for reading, find that
they can now read without glasses.
Phacomorphic glaucoma: Cataract can
increase the lens size causing shallowing of
the anterior chamber and angle closure
Phacolytic glaucoma: Lens protein leaks
form the lens and elicits a macrophagic
response. The inflammatory material blocks
the flow of aqueous through the trabecular
Phacoantigenic uveitis: This is caused by
lens protein released through a ruptured
lens capsule causing a granulomatous
A posterior chamber
An anterior chamber
lens in an eye with
hazy cornea. This is
An iris clip lens (Binkhorst
lens). This lens is not
longer favored due to the
risk of iritis, lens
Capsulorrhexis provides a stronger edge
and allows phacoemulsification to be
carried out safely.
The implant can be held more securely
and gives a better centration.
Ideally, if the lens were to be placed in
the sulcus, the power of the lens (with
the same A constant) is reduced by 1/2 D
from that calculated pre-operatively.
In this case, the focal point is moved
anteriorly, and the patient becomes
Cystoid macular edema = Irvine-Gass syndrome.
Typically seen 4-8 weeks following the cataract
More common after
intracapsular than extracapsular cataract extraction.
presence of iris or vitreous incarceration.
Treatment is controversial and the great majority
improves without treatment.
Treatment options include:
Topical steroid or non-steroidal anti-inflammatory medications.
Acetazolamide is often given and is believed to reduce the macular
Iris or vitreous incarceration
Freeing the iris and vitrectomy can improve the edema.
• There is a circular
imprint of pigment
on the anterior
• This may result
• It is of no visual
• Rosette cataract.
• This is typical of
resulting from blunt
• The cataract begins
in the subcapsular
region and with time
become buried in
• Vision is usually
• There is a star
shaped opacity in
• This is seen in
more than 2 years.
• Vision may be
normal as this type
of cataract seldom
An aphakic eye with broad
iridectomy and peripheral
An aphakic eye with
corneal edema as a
result of vitreous touch.
The patient may be wearing thick lenses or
In intracapsular cataract extraction, there is
usually iridectomy and the presence of vitreous
in the anterior chamber (examine the cornea for
any decompensation due to vitreous touch).
Some patients may have extracapsular cataract
extraction without implant (for example in clear
lens extraction for high myopia).
In young children with aphakia, consider:
Lens dislocation such as Marfan's syndrome
Cataract extraction in juvenile chronic arthritis, look for
cells and flare in the anterior chamber and band
Direct ophthalmoscopy on a high myopic patient
with aphakia requires relatively low minus
(concave) power on the ophthalmoscope.
Reduced visual field
Pin cushion effect
Weight of glasses
Eyes appear large
An phakic eye which is myopic with an
axial length of 31mm is equal to -21D.
Clear lens extraction can fully correct a
myopic eye measuring -21D.
A subluxated lens in the
superior nasal direction.
fingers) in a Marfan's
High arch palate in a
If the eye is not dilated:
Iridodonesis (abnormal tremor of the iris)
Phacodonesis (abnormal movement of the lens)
Deep AC depth or vitreous herniation into AC.
Signs of Marfan's syndrome
Superior nasal subluxation of the lens; Arachnodactyly;
High arch palate; Arm span longer than height
Downward subluxation of lens; Same features as
Marfan's syndrome; Patient tends to be mentally
subnormal and may have fair hair.
In Weill-Marchesani's syndrome:
Mental retardation; short stature; stubby fingers
look for pseudoexfoliation syndrome
look for signs of trauma which is the most
common cause of subluxated lens.
This is pseudoexfoliation syndrome.
Pupil dilatation is poor and there is risk of zonular dialysis.
The patient has hyper-extensibility of the joint. This is a sign of Ehler-Danlos's
The patient is at risk of lens subluxation.
This patient has physical signs of ankylosing
spondylitis (stiff back and kyphosis).
The problems encountered will include:
- Posturing of the patient during operation
- Poorly dilated pupil due to anterior synechiae
K1 = 42.75
K2 = 42.50
AL = 21.75 mm
Refraction = - 8.25 D
VA = 6/24
K1 = 42.25
K2 = 42.50
AL = 22.00 mm
Refraction = - 7.55 D
VA = 6/24
• This patient's biometry shows average keratometry readings and axial
lengths but high minus refraction.
• These changes are seen in patients with significant nuclear sclerosis. The
lenses are likely to be large and hard.
• A large lens will give a shallow anterior chamber making capsulorrhexis
difficult for the inexperienced surgeon.
• A hard nucleus increases the phaco time and in the hand of inexperienced
surgeon complications such as corneal edema is increased.
Cystic bleb indicating a
Adrenochrome pigments on the lower
lid tarsal conjunctiva seen with topical
Physical signs of the treatment the patient is
Physical signs for possible causes (e.g. PDS,
Physical signs indicating the severity of the
Surgery (Traby, tube, iridectomy)
Poor drainage is suggested by an absence of
bleb or a dome-shaped vascularized bleb caused
by subconjunctival fibrosis
Constricted pupil (Pilocarpine)
Heterochromia iridis (Latanoprost)
Most common cases of 2ry
with anterior physical signs are:
Pigment dispersion syndrome
Iridocorneal endothelial (ICE) syndrome
Fuch's heterochromic cyclitis.
Less trauma to the
Poorer scleral exposure
Higher chance of button
Better exposure of limbus
More diffuse bleb due to
the lack of a posterior scar
line to limit the extension
of the bleb
Easier technique & less
Frequent wound leaks
Risk of corneal trauma
Low IOPLow IOP
Re-suturing is needed if
leakage fails to stop after
Patching may be useful.
shallowing of AC with
If it persists for 10-14
days post-op, surgical
drainage is needed plus
High IOPHigh IOP
Angle closure glaucoma
YAG iridotomy is needed.
Most cases respond to
medical Rx (cycloplegic,
B-blockers and systemic
failure to Med Rx:
Nd:YAG laser to disrupt
the posterior or anterior
hyaloid if the eye is
phakic or aphakic.
Alternatively, par plana
vitrectomy is useful.
In phakic eye, pars plana
Age of patient: young more than old
Race of patient: black more than other
Type of glaucoma: traumatic, uveitic &
neovascular are more likely to fail
Previous failed surgery
Use of certain topical medication such as
• The iris and the lens
show dandruff-like flakes.
• The flakes on the lens are
arranged in a bull-eye
fashion with an
intermediate clear zone.
• The corneal endothelium
• Retroillumination shows
• Look for:
• Traby, OD cupping,
The exact source is unknown.
It may be produced by the epithelium of
the lens and other tissues because the
material is not confined to the eyes.
The condition is thought to be a
generalized disorder of the basement
Bio-chemically, the material is made up of
proteoglycan materials and has features of
Cataract operation does not stop its
About 60% of patients with
pseudoexfoliation syndrome develop
secondary open angle glaucoma.
Compared with primary open angle
glaucoma, this type is less responsive to
Argon laser trabeculoplasty is useful
initially to control the pressure but this is
eventually lost (sometimes abruptly).
Trabeculectomy is useful and has the
same success rate as POAG.
A line of pigment
to Schwalbe's line
Poor pupillary dilatation.
Weak zonules predisposes to zonular
dehiscence. This risk is increased with
vigorous hydrodissection or excessive nucleus
manipulation during Phacoemulsification.
Increased risk of posterior capsular
Opacities behind anterior
lens capsule resulting from
anterior epithelium necrosis
situated peripherally &
Eye with previous acute
glaucoma (irregular pupil)
The AC is usually shallow but may be normal in pseudophakia.
The lens contains white opacities anteriorly.
The iris may show atrophy from ischemic changes with irregular pupil which
may react poorly to light.
Peripheral iridotomy is usually present. Assess patency.
Not all cases of acute glaucoma are
treated with laser iridotomies.
You may have patients who had had
surgical iridectomies. With a casual
examination, this may be mistaken for
trabeculectomy without a functioning
bleb. The clue to this is the absence of a
scleral flap, glaucoflecken and iris
Examine the opposite eye for
prophylactic treatment whether laser or
Primary angle closure glaucoma:
The mechanism is due to pupillary block.
The AC is shallow both centrally and peripherally.
Plateau iris syndrome:
The main mechanism is caused by occlusion of the
trabecular meshwork by the anteriorly positioned
Patients are younger (fourth or fifth decade of life).
The AC is deep centrally.
Patients with plateau iris syndrome may not respond to
laser iridotomy like primary angle closure glaucoma.
Laser peripheral iridoplasty or miotic therapy may be
Shallow anterior chamber
Small corneal diameter
Short axial length of globe
Large crystalline lens
Patients with narrow angle may develop
AACG when the pupil is dilated due to
Provocative tests may be used to identify
the latent cases; the result is positive if
there is 8 mmHg pressure rise in the first
The provocative test may be:
Physiological: for example the dark room test
in which the pressure of the test is checked
when the pupil becomes dilated in the dark or
Pharmacological with 10% phenylephrine
(which is reversible with thymoxamine)
Radial transillumination of the iris in
the midperiphery region. This is seen
with retroillumination. Each area
represents area devoid of pigment
spindle with diffuse
The corneal endothelium contains
vertically orientated deposition of
pigments (Krukenberg's spindle).
The pigment may also be seen on the
iris, lens and the trabecular meshwork
Pigment in the trabecular meshwork by
Any peripheral iridoctomies which may be
performed in an attempt to reduce the
production of pigment
look at the patient's glasses, most of this
patients has myopia
Examine the optic disc for cupping
What percentage of patients with PDS
develop glaucoma ? 30%30%
Patients with PDS typically shows wide
fluctuation of the intraocular pressures.
The pressure may be normal in the clinic
but can rise quickly following exercise or
pupillary dilatation in the dark.
The iris is bowed posteriorly, causing it to
rub against the lens zonules.
This results in the loss of the pigment
epithelium resulting in transillumination
and the endothelium deposition of
The vertical orientation of the pigment is
due to conventional current.
It equalizes the pressures between the
posterior and anterior chamber and
therefore corrects the posterior bowing of
This reduces the rubbing and thus
decreased pigment loss.
A tube which enters the anterior chamber through the limbus region. This is a seton
used for glaucoma operation. Molteno's tube is the most commonly used
Presence of signs indicating the
It is used for refractory glaucoma
Previous multiple failed filtration procedures
Conjunctival scarring from previous failed
filtration (making the development of a filtration bleb
Childhood glaucoma in which primary
procedures have failed
All setons contain a tube and a plate.
The tube is inserted into the anterior
chamber to drain the aqueous and is
made up of either silicone or silastic.
The plate forms the reservoir for the
drained aqueous and is made up of
plastic or silicone.
The main difference between different
setons is in the design of plates.
Excessive drainage leading to hypotony.
Modification through valve insertion has
been made to the tube and plate to make
the seton pressure-dependent.
There is iris atrophy with corectopia and polycoria
Iridocorneal endothelial syndrome (ICE)
The eye may have previous glaucoma
The cornea may show signs of
decompensation with corneal edema.
The endothelium shows guttate-like
A tube in the anterior chamber
Signs of glaucoma in posterior segment
The main abnormality is in the corneal
endothelium appears like the epithelium.
The endothelium becomes several layer
thick and spreading over the TM and iris
The cause is unknown.
Essential iris atrophy: There is progressive
angle closure by:
peripheral anterior synechiae
Corectopia, polycoria and iris atrophy. T
he changes are the results of pulling by the
Iris naevus syndrome (Cogan-Reese):
Angle changes are as above
Diffuse naevus covering the anterior iris.
Iris nodules may or may not be present. The
nodules are the results of iris stroma protruding
through the abnormal endothelium growing over the
Chandler's syndrome falls between the above
The iris contains irregularly arranged blood vessels
Seton tube in the anterior chamber which
may be used to treat this condition
Examine the posterior segment;
Central retinal vein occlusion
This is neovascular glaucoma secondary
to ischaemic central retinal vein
Small keratic precipitates scattered throughout the corneal endothelium (stellate
keratic precipitates). Fuch's heterochromic cyclitis
The iris may show:
Hhypochromia (best seen in the day light)
Iris transillumination due to iris atrophy
There may be irregular fine vessels on the iris
The patient may have posterior subcaspular
The anterior chamber may have flare or cells
The conjunctiva is white
NO Posterior synechiae
The iris may contain abnormal iris vessels
Check for the presence of trabeculectomy
This tends to be chronic and not responsive to
Steroid may increase the risk of glaucoma and
May respond initially to medical treatment
Trabeculectomy is usually needed.
Bleb failure is common. Antimetabolites is
Extraction and heparin surface-modified IOL is
the pupil may not dilate well due to iris
Hyphema from the abnormal iris vessels is
common (Amsler's sign)