Lecture lens

Monday, March 20, 2017 1anjumk38dmc@gmail.com

LECTURE: 1 LENS
Prof Md Anisur Rahman
Head of the department (Eye)
Dhaka Medical College. Dhaka
Monday, March 20, 2017 anjumk38dmc@gmail.com 2

Cross section of human crystalline lens

Human Crystalline Lens: (Applied anatomy)
 The lens is a transparent, biconvex, crystalline structure placed
between iris and the vitreous in a saucer shaped depression.
 Diameter is 9-10 mm
 It has got 2 surfaces: the anterior surface is less convex (radius
of curvature is 10 mm) than the posterior (radius of curvature
6 mm) The two surfaces meet at the equator.
 Its refractive index is 1.39 and total power is 15-16.

Human Crystalline Lens (Histopathology)
Structure
1) Lens capsule: It is a thin, transparent, hyaline membrane
surrounding the lens which is thicker over the anterior than
the posterior surface. The lens capsule is thickest at pre-
equator regions and thinnest at the posterior pole.
2) Anterior epithelium: It is a single layer of cuboidal cells
which lies deep to the anterior capsule. In the equatorial
region these cells become columnar, are actively dividing and
elongating to form new lens fiber throughout the life.

Human Crystalline Lens (Histopathology)
Structure
• 3) Lens fiber: The epithelial cells elongated to form lens fiber.
It form throughout the life, the older fiber resides in the centre
and form the nucleus and the peripheral called cortex.

What is cataract?
• Opacity of the human crystalline lens and its
capsule is called cataract.

Classification of cataract
A. Etiological classification
I. Congenital & developmental cataract
II. Acquired cataract
1. Senile cataract
2. Traumatic cataract
3. Complicated cataract
4. Metabolic cataract

5. Radiation cataract
6. Toxic cataract
7. Cataract associated with skin diseases
8. Cataract associated with miscellaneous syndromes
i. Dystrophic myotonic
ii. Down’s syndrome
iii. Lowe’s syndrome

B. Morphological classification: It involves the capsule & may be
1) Capsular cataract
i. Anterior capsular cataract
ii. Posterior capsular cataract
2) Subcapsular cataract: It involves the superficial part of the
cortex (just below the capsule) and includes:
Anterior subcapsular cataract & Posterior subcapsular cataract

3) Cortical cataract: It involves the major part of the cortex
4) Supranuclear cataract: It involves only the deeper part of the
cortex
5) Nuclear cataract: It involves the nucleus of the crystalline
lens.
6) Polar cataract: It involves the capsule and superficial part of
the cortex in the polar region only. It may be:
 Anterior polar cataract & Posterior polar cataract

Cataract maturity (This classification is only for
Age related cataract)
1. Immature cataract: is one in which the lens is partially
opaque.
2. Mature cataract: when lens is completely opaque.
3. Hyper mature cataract: has a shrunken and wrinkled anterior
capsule due to leakage of water out of the lens.
4. Morgagnian cataract: is a hyper mature cataract in which
liquefaction of the cortex has allowed the nucleus to sink
inferiorly

Classification of cataract (Congenital &
Development cataract)
A. Hereditary: About one third of the congenital cataract is
hereditary. Mode of inheritance is autosomal dominant
B. Maternal factor:
1) Malnutrition
2) Infection
3) Drugs ingestion
4) Radiation

Development cataract). Aetiological
C. Fetal or Infantile factors:
i. Deficient of oxygenation: Owing to placental haemorrhage
ii. Metabolic disorder: Galactosemia, galactokinase deficiency
iii. Cataract associated with other congenital anomalies: Lowe’s
syndrome, myotonica dystrophica
iv. Birth trauma
v. Malnutrition

Development cataract)
• D. Idiopathic

Morphological classification of
congenital/Developmental Cataract
1) Congenital capsular cataract
 Anterior capsular cataract
 Posterior capsular cataract
2) Polar cataract
 Anterior polar cataract
 Posterior polar cataract
3) Nuclear cataract
4) Lamellar cataract

5) Sutural & axial cataract:
 Floriform cataract
 Coralliform cataract
 Spear-shaped cataract
 Anterior axial embryonic cataract

6) Generalized cataract
 Coronary cataract
 Blue dot cataract
 Total congenital cataract
 Congenital membranous cataract

Difference between immature & mature cataract
Immature cataract
1) Considerable vision present
2) Colour of the lens is
grayish white
3) Iris shadow present
4) Fundal glow present
Mature cataract
1) Vision is reduced to CF
2) Colour of the lens is pearly
white
3) Iris shadow absent
4) Fundal glow absent

How the visual acuity measure with Snellen’s
chart
1) 6/60
2) 6/36
3) 6/24
4) 6/18
5) 6/12
6) 6/9
7) 6/6

Reversible blindness
1) Cataract is most common
2) Refractive error
3) Corneal opacity due to trauma, ulcer etc
4) Diabetic retinopathy

Irreversible blindness
1) Primary open angle glaucoma (POAG)
2) Age related macular degeneration (ARMD)
3) Some retinal dystrophy or degeneration

LECTURE: 2. Lens
Head of the department (Eye)
Dhaka Medical College. Dhaka

Symptoms of cataract
1) Gradual dimness of vision
2) Sometimes mono ocular diplopia in early
stage

Signs of Immature cataract
1) Considerable vision present
2) Colour of the lens is grayish white
3) Iris shadow present
4) Fundal glow present

Signs of Mature cataract
1) Vision is reduced to CF
2) Colour of the lens is pearly white
3) Iris shadow absent
4) Fundal glow absent

Treatment of cataract
In early stage, change of spectacle
But the surgical treatment depends upon the
patient choice and profession of the patient.

What are the surgical treatment of cataract
There are two types of cataract surgery
1) ICCE (Intracapsular cataract extraction) Now
obsolete
2) ECCE: (Extra capsular cataract extraction)

The basic difference between the two
surgeries are:
• In ICCE the lens is extracted along with total
capsule of the lens, so no IOL can be
implanted in posterior chamber
• But in ECCE the posterior capsule of the lens
is remain intact so IOL can be implanted in
posterior chamber

Various types of Extracapsular Capsular Cataract
Extraction
1) Extra capsular cataract extraction with
posterior chamber intra ocular lens
implantation (ECCE with PC IOL)
2) Small incision cataract surgery with posterior
chamber intra ocular lens implantation (SICS
with PC IOL)
3) Phacoemulsification with posterior chamber
intra ocular lens implantation (Phaco with PC
IOL)

Among these 3, SICS with PC IOL & Phaco
with PC IOL is the treatment of choice

What investigation will you do before
cataract surgery?
Systemic investigations:
 Blood sugar: Cataract surgery will not perform if
blood sugar is above 10 two hours ABF.
 ECG: Not always
 Ocular investigation:
 IOP
 SPT
 Biometry

What is SPT?
SPT: Sac patency test. It is done to check whether the
lacrimal passage is open or not. If the draining
passage is blocked cataract surgery will not perform.
We have to clear the passage by doing surgery.
 We have to do DCR/DCT according to patient
condition.

What is biometry?
Biometry is the procedure by which we detect the
intra ocular lens power before surgery.
How to perform biometry?
 To calculate the IOL power which we put inside the
eye during surgery
 Two instruments are needed to calculate the IOL
power.
 Keratometer
 A scan ultra sonogram

Biometry
There is a formula to calculate the IOL power.
P = A – {(2.5xAL) + (0.9 x K)}
Here,
P = Power of the IOL
A = Constant (which is printed over the lens box)
AL = Axial length of the globe
K = Keratometer reading (Diopter power of cornea)

Biometry
• With the help of A-Scan we measure the axial
length of the globe
• We the help of kerato meter we measure the
diopter power of the cornea.

Anaesthesia used in cataract surgery
Cataract surgery usually perform with local
anaesthesia
There are 2 types of block
1) Retrobulbar
2) Peribulbar
 In some cases, such as children & non cooperative
patient we use G/A.
 Some surgeons prefer topical Oxybuprocaine 0.4%
in phaco surgery.

ANAESTHETIC SOLUTIONS:
Lignocaine (lidocaine) 2%: Fast onset of action and
effects last for an hour.
Bupivacaine 0.5% : slow onset of action but lasts for
3-4hrs
Hyaluronidase (7.5 units/ml): Spreading agent

Retrobulbar block
The globe should be in primary gaze, looking straight
up towards the ceiling. The inferior orbital rim is
palpated through the lower eyelid.
The needle should be oriented with the bevel facing
up towards the globe. This further protects the globe
from penetration during injection.

Retrobulbar block
• The needle is then inserted through the lower eyelid,
just superior to the lateral third of the inferior orbital
rim. The temporal limbus is used as a guide, as shown
in the image below.
• The needle is advanced posteriorly parallel to the
orbital floor, which has an approximate incline of 15
degrees.

Retrobulbar block
• When the needle is approximately 50% passed (at this
point the tip of the needle will have passed the
equator of the globe), the angle of injection is shifted
medially and further superiorly to 45 degrees
allowing the needle to enter the intraconal space.

Retrobulbar block

Peribulbar block
Peribulbar block is very similar to the retrobulbar block.
Anesthetic is injected into the orbit; however, it is
administered outside of the muscle cone. Because of
this fact, this technique is lower risk than the
retrobulbar block, but achieves a lesser degree of
anesthesia and especially akinesia

Peribulbar block
• Peribulbar block should be given in upper and lower
Upper one should be given at the junction of medial
1/3 and lateral 2/3 of the superior orbital rim
Lower one should be given at the junction of lateral
1/3 and medial 2/3 of the inferior orbital rim
• (5ml should be given in each time)

Complication of block
Complication due to anaesthetic agent:
• Hypersensitivity reaction
• Syncope
Complication due to faulty technique
• Retrobulbar hemorrhage
• Perforation of the globe
• Optic N injury

Pre operative preparation of cataract surgery
I. Topical antibiotic hourly from the day before surgery (except
sleeping time)
II. Sedative (night before surgery) according to patient choice.
III. Tab Acetazolamide & Tab Potassium supplement at C/M.
IV. Phenylephrine + Tropicamide eye drop 15 minute interval for
3 to 4 times before surgery to dilate the pupil.

Solve the problem
A patient 65 year old came to you for cataract surgery
(R/E) and he desires to do phaco surgery with PC
IOL, O/E you got visual acuity of R/E is 6/36. L/E is
aphakic but with glass of +10 D his visual acuity is
6/9.
Now how you manage/counsel the patient?

Lecture: 3
17 May 2016
Head of the department (Ophthalmology)
Dhaka Medical College, Dhaka

Steps of SICS.
Step: 1Expose the eyeball
• After draping the field is ready to surgery
• Step: 1
Expose the eye ball with the help of universal
speculum & superior rectus bridle suture with 4/0 or
5/0 atraumatic silk

Steps of SICS.
Step: 1Expose the eyeball
Fig: 1. Superior Rectus hold
with Tooth forcep and needle of
the atraumatic silk hold with
Silcock's needle holder
Fig: 2. Now the eyeball is
exposed with Universal eye
speculum & Superior Rectus
bridle suture

Steps of SICS.
Step: 2. Construction of scleral tunnel
Give incision to the conjunctiva and expose
the sclera about 1.5 to 2 mm above the sup limbus.
Give incision (crescent
shaped or straight)
to the sclera (half or
2/3 thickness) with
crescent
knife. FIG: 3

Steps of SICS.
Monday, March 20, 2017 56FIG: 4m
Then make a tunnel with
the crescent knife upto 1.5
to 2 mm of the cornea.
Then enter into A/C with
the help of keratome.
FIG

Steps of SICS
Step: 3. Anterior capsulotomy
Crescent knife Keratome

Steps of SICS
 Before Anterior capsulotomy stain the capsule with
bluerex
 Wash A/C with Ringer’s/Basal Salt Solution (BSS)
 Insert visco elastic substance (Methyl Cellulose) into
A/C to maintain the A/C depth.
F
Capsule is
stained
with
bluerex
FIG: 5

Steps of SICS
• There are 3 types of anterior capsulotomy
1) Can opener
2) CCC (Continuous Curvilinear Capsulorhexis)
3) Envelope type
Capsulotomy is done with the help of Cystitome
(Cystitome is nothing but the double bent
hypodermic needle)

Steps of SICS
FIG: 6. CCC FIG: 7. Can Opener

Steps of SICS
Step: 4 hydrodissection & hydrodelination
• This step is not mandatory for SICS but phaco.
FIG: 8. If hydrodissection is
complete there will appear a Golden
Ring Surrounded the nucleus
FIG: 8. Golden ring is
seen.

Steps of SICS
Step: 5 & 6. Removal of the nucleus
• Step: 5. The nucleus will be prolapse into the A/C
with the help Sinsky hook or Cystitome needle.
• Step: 6. The nucleus will be delivered with the help of
Vectis loop (many surgeons use different instrument
for nucleus delivery) FIG: 9

Steps of SICS
Step: 6 Removal of the nucleus
FIG: 9 Removal of the nucleus with the help
of wire loop vectis

Steps of SICS
Step: 7. Cortical matter clean up
• Step: 7. When nucleus is delivered only cortical
matter is there. So cortical matter has to removed.
This step is called irrigation & aspiration.
• It is clean up with the help of Simcoe cannula. It is
also called two-way cannula

FIG: 10. Irrigation & Aspiration
cannula (I & A cannula)

Steps of SICS
Step: 7. How cortical matter clean up with I/A cannula?
The 2-way cannula is
attached one side with 5 cc
syringe & the other end with
the saline set.
When the saline is on fluid
enter into the A/C.
The syringe which is
attached with other end will
aspirate cortical matter from
A/C.

Intraocular lens made
by Polymethylmeth
Acrylic Refractive
index is 1.49
Intraocular lens has two parts.
1) Two haptic for anchoring
2) Optical part. Lens power is in
optical part

Before insertion the lens is hold
with tying forcep or Mc Pherson
forcep

• After insertion of the lens the anterior chamber
washed with Ringer’s/BSS.
• Check whether A/C is normal depth or shallow. If
A/C is shallow give a bite with 10/0 monofilament
nylon.
• Lastly, apply pad for 24 hours

Lecture: 4
Head of the department (Ophthalmology)
Dhaka Medical College, Dhaka

After cataract surgery what advice should you
give to the patient?
1) Do not use water in your eyes
2) Use dark black sun glass
3) Do not lean forward
4) Use medicine regularly
5) Come after 7 days or before if any problem
Abide by these rules for 4 weeks (for SICS) 2 weeks for
phaco surgery

Post operative order (oral medication)
1) Systemic antibiotic: Usually Tab Ciprofloxacin (500
mg) for 7 days
2) Analgesic (Paracetamol preferably) if pain along
with anti ulcerant.
3) Tab Acetazolamide (250) and potassium supplement
If IOP is raised

Post operative order (eye drop)
1) Antibiotic eye drop (Moxifloxacin/Levofloxacin):
1 drop 4 to 6 hourly for 1 month
2) Steroid eye drop (Dexamethason/Prednisolone)
 I drop 2 hourly for 7 days
 1 drop 4 hourly for 15 days
 Then tapper (total dose will be 6-8 weeks)
3) Tropicamide 1% eye drop 8 hourly for 2 weeks

Complications of cataract surgery
• In broad heading we can divided complications of
cataract surgery into 3 stages:
1) Pre operative complications: due to anaesthetic
agent
2) Per operative complications: During surgery
3) Post operative complications: We can divided it into
two groups:
a) Early post operative
b) Late post operative

Pre operative complications
Usually it is due to anaesthetic agent and discuss
previously

Per-operative complications of SICS
Per operative: According to stages of surgery
a) Improper tunnel construction.
b) Early entry into A/C
c) Anterior capsular tear during entry into A/C
Step: 3. Anterior capsulotomy: In SICS usually no
complication, but in phaco there may be radial tear
into capsule & phaco may be turn into SICS

Complications of SICS
• Step: 6. Removal of the nucleus:
a) There is high risk, to corneal endothelial injury
which may ultimately causes bullous keratopathy.
b) Iris injury & iridodialysis.
c) There is chance of PCT (posterior capsular tear)
d) Vitreous loss (VL)
e) There is chance of nucleus drop into vitreous

• Step: 7. Cortical clean up
• During cortical clean up there is chance of PCT &
VL

Early postoperative complications
1) Wound related:
i. Wound leak
ii. Iris prolapse
2) Cornea:
i. Corneal striate
ii. Corneal oedema
3) Anterior chamber:
i. A/C reaction
ii. Hyphaema
iii. TASS (Toxic Anterior Segment Syndrome)

Early postoperative complications
4) IOP related:
i. Raised
ii. Low
5) IOL related
i. Decentered
ii. Dislocated
iii. Tilted
iv. Pupil capture
6) The most devastating: Acute endophthalmitis

Late postoperative complications
1) Delayed-onset endophthalmitis following cataract
surgery develops when an organism of low virulence
such as P. acnes, becomes trapped within the capsular
bag (saccular endophthalmitis).

Late postoperative complications
2) Visually significant posterior lens capsular
opacification (PCO), also known as ‘after cataract’,
is the most common late complication of
uncomplicated cataract surgery, historically
occurring
3) contraction of the anterior capsular opening
(capsulophimosis)

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