LENS NOTES

LENS

LENS  DEVELOPMENT

• 3rd week→ Ectoderm overlying the optic vesicle thickens  to form – LENS PLACODE
• Cells of len placode arc posteriorly to form a concave depression- LENS PIT
• Margins of the lens pit fuse to form- LENS VESICLE
• Cells of the post wall elongate to form the lens fibres
• Ant wall remains as a single layer of cubical epith & the vesicular lumen gradually obliterates.This is the EMBRYONIC NUCLEUS [ 4th wk]
• 5th wk→ Cells of the lens produce a true BM i.e –LENS CAPSULE
• 2nd mo→ Lens fib terminate into ‘Y’ shaped sutures- Upright-ant surface & inverted – post surf
• 3rd-8th mo – FETAL NUCLEUS
• Last wk of fetal life to puberty- INFANTILE NUCLEUS
• After puberty→ ADULT NUCLEUS

LENS CRYSTALLINES [D-O4]

• Lens proteins- 2parts

1. Albuminoid-insoluble-present in nucleus
2. Crystallines
• -soluble
• -present in cortex
• -make up bulk of refractive fibres of lens,therefore considered structural proteins
• -Synthesis occurs on the surface & equator of lens
• - 3 components-
• 1}  alpha- 31.7%-highest mol wt
• 2}  Beta  -53.4 %
• 3} Gamma- 1.5 %

 

Cataract means-WATERFALL

STAGES OF CORTICAL CATARACT-

1. Lamellar separation
2. Incipient stg [ISC]
3. Intumescent stg [ISC]
4. Mature
5. Hypermature

• morgagnian type
• Sclerotic type

INCIDENCE of cataract blindness-80.7%

                            AFTER-CATARACT-case

DEF-

Membranous white opacity formed by the remnants of anterior & posterior capsule after cat extrn

Also k/as posterior capsular opacification.0r secondary cataract

MECH OF FORM-

• In immature cat , some soft cortex sticks to the capsule & is diff to remove.
• This gets entrapped by adhesion of ant capsule remnants to post cap.
• The cuboidal cells lining the ant capsule continue to form new lens fibres which are opaque.

TYPES OF PCO-

Nmlly lens epith cells are present on anterior surf,equatorial region & equatorial bow

Fibrosis type-

-Lens epith cells are present behind the anterior lens capsule.

-They do not undergo mitosis

-When stim they proliferate & undergo fibrous metaplasia

Pearl type-

• Lens epith cells are present in the equator
• Undergo active mitosis
• Form new lens fibres

FACTORS INFLUENCING PCO-

1.Heparin reduces PCO

2.Epith cells shud be removed by polishing the capsule

3. CCC prevents PCO

4. PCO Occurs more frequently in children b/o greater proliferative potential of epith cells in younger age grp.Posterior capsulorhexis prevents PCO

5. Uveitis→ more inflammation→ more PCO

6. IOL design- If part of IOL is snugly apposed to PC,chances of PCO are less.Hence posterior convex or biconvex lenses are preferred.

- Post angulation of IOL optics will enhance optic capsule  contact.

    -In the bag IOLs stretch the bag & this stretched capsule remains in apposition with the posterior surface of IOL

           -PMMA is better than polypropylene as it has better memory & on insertion into the bag ,they come to their original shape & stretch the bag

SOEMMERRING’S RING-

Ring behind the iris formed by lens fib enclosed bet the two layers of lens capsule.

Causes-

1. Incomplete cortex removal
2. Trauma

ELSCHING’S PEARL-

The subcapsular cuboidal cells proliferate & instead of forming lens fibres form large balloon like cells (Wedl cells) which fill the pupillary aperture.

Meticulous hydrodissection & cortical clean-up prevents PCO

TREATMENT-

A] Nd:YAG Capsulotomy-

-Distant Direct Ophthalmoscopy→ tells abt media opacity

-Direct O’scopy → to assess severity of PCO

                               -to rule out CME

-Procedure-

* Apraclonidine E/D one hour prior & on completion

* Power- 1mJ/ pulse

* A series of  punctures are applied in a cruciate pattern,the first puncture aimed at the visual axis

*  A 3mm opening is adequate

-Complications-

1. IOL pitting

2.CME- less common when c’tomy is delayed for 6mo or more

3. Rheg RD

4.rise in IOP

5.Post IOL subluxation / dislocation

6.Chr endoph- d/t release of sequestered org into the vitreous

Q. VIVA- MC type of congenital cataract-

A – Lamellar cataract

Q- Advantages of capsulorrhexis over capsulotomy-

A- 1. Stronger edge

    2. Implant can be held more securely

    3. Better centration

SUBLUXATED LENS  [D-04,j-07]-case-

Instrum-wire vectis

CAUSES-

1.Trauma

2. Hereditary-

• Marfan’s sy
• Ehler Danlos syn
• Weil Marchesani sy
• Crouzon sy
• Aniridia

3. Congenital-

• Buphthalmos
• ectopia lentis

4. Metabolic-

• Homocystinuria
• Hyperlysinemia
• Sulphite oxidase def

5. High myopia
6. HMSC
7. Acqd syphilis
8. PXF

SYMPTOMS-

-DOV

-Monocular diplopia

SIGNS-

• Decentered lens
• Iridodonesis
• Phacodonesis
• Marked astigmatism
• Asymmetry of AC depth

COMPLICATIONS-

1. Astigmatism
2. Monocular diplopia
3. Uveitis
4. Pupillary block glaucoma

T/T- [J-07]

1] FOR SUBLUXATED CLEAR CRYSTALLINE LENS-

-Spec correction thru the aphakic or phakic part ,whichever part is more

- Miotics & mydriatics

2] FOR CATARACTOUS LENS-

For small zonular tear→

ECCE + PCIOL  + CAPSULAR TENSION RING

If the zonular tear is more→

ICCE with vectis is the t/t of choice.This is followed by anterior vitrectomy + /- ACIOL.

Sometimes, a scleral fixated IOL may be considered when the other eye is normal or pseudophakic

Routes for approach-

1. Limbal approach

2. Pars plana approach

3] FOR ANTERIOR DISLOCATION-

Remove as early as possible\

Immediate ICCE + Vitrectomy + /- AC IOL

4] FOR POSTERIOR  DISLOCATION-

-

1. Fixed to retina- Leave it

Only aphakic glass is prescribed

2. Mobile→ It can cause→ * glaucoma

                                            * inflammation

                                            * obstruct visual axis

Go for surgical removal by pars plana approach

First do a complete vitrectomy

Then lens removal by

1] Limbal route-with MVR blade

                        Or – endocryo

                        Or – PFCL→ float the lens away from the retina

                                               & then remove

2]Pars plana route-

Lens is floated with PFCL in midvitreous→ crushed with endoilluminator & V’tomy probe→ removed with V probe or phacofragmentome.This method is better as damage to retina is less as the  lens is removed in midvit &AC is not opened

A scleral fixated IOL can be implanted.

C/I of scleral fixated IOL-

-Inflam

iritis

EXPULSIVE H’AGE-viva

SIGNS

5. Shallow AC
6. Iris prolapse
7. Vitreous extrusion
8. Dark mass behind the pupil
9. Loss of red reflex
10. Extrusion of IO contents

                       LOCAL ANAESTHESIA

• Topical
• Retrobulbar
• Peribulbar
• Facial

AGENTS-l

1. Inj Lignocaine ( 2%)

• Onset of action- 5-10min
• DOA-45min-2hrs

2.Inj bupivacaine (0.5-0.75 %)

-onset- 15-20 min

-DOA- 5-8 hrs

Adjuvants-  

1. Inj Adrenaline (1 in 100,000)

• Vasoconstriction→ reduces systemic absorption of anaes agent
• Reduces blding
• Prolongs DOA
• C/I- HT, IHD

2. Inj Hyaluronidase ( 75-150 units/10 ml)

-Enhances diffusion of anaes agent

FACIAL BLOCK-

Block Facial N or its zygomatic br→ paralyze the orbicularis oculi→prevents closure & squeezing of lids

1.O’BRIEN’S TECH-

At the neck of mandible just in front of tragus

2. VAN LINT’S TECH-

1cm below & behind the lateral canthus→ along superolateral orb margin→ along inferolat orb margin

3. ATKINSON’S TECH-

     Post to a vertical line drawn from the lat orb margin→along the zygomatic arch→ towards the top of the ear.

      4.NADBATH  ELLIS TECH-

     Bet the anterosuperior border of mastoid  process & ramus of mandible

RETROBULBAR BLOCK-

AIM-

To block the III n before it enters the 4 recti in the post intraconal space.

EYE POS-

Primary gaze bcos the ON is directed away from the path of needle

INJ SITE

Junctn of medial 2/3rd & lateral 1/3rd of inferior orbital margin in the muscle cone

EFFECTS-

1. anaesthesia of iris
2. Akinesia of EOM [ except SO]
3. Mydriasis
4. Hypotony
5. Proptosis
6. Decrease oculo-cardiac reflex

COMPLICATIONS-

1. Retrobulbar h’age
2. Ocular perforation
3. Subarachnoid / intradural h’age→ brainstem anaesthesia
4. Respiratory arrest
5. Optic N contusion & atrophy
6. Retinal vas occlusion
7. Fall in V/A
8. Hypotony
9. Ms – Ptosis, entropion & diplopia

ADVANTAGES-

1. Excellent akinesia & anaesthesia
2. quick onset of block
3. Low vol of anaesthetic- lower intraorbital tension

                                            -Less chemosis

    

   DISADVANTAGE-

   Higher complication rate

PERIBULBAR BLOCK-

AIM-

To instill LA outside the ms cone & avoid proximity to optic N.

EYE POS-

Primary gaze

INJ SITE-

Junctn of med 2/3rd  & lat 1/3rd of lower orbital margin outside the ms cone

ADVANTAGES-

1. Less- RBH

• Globe perforation
• ON damage

2. Less painful
3. No need of additional facial block

DISADVANTAGES-

1. Longer time to achieve akinesia
2. Chemosis & lid edema
3. Ptosis

Q  Causes of posterior subcapsular cataract-

A –1.Steroids

     2.DM

     3. chr inflame

     4. RP

     5. Trauma

Q.what are the problems with PSC?

A –Diff in near vision

  - night glare

Q what are the complications of a morgagnian cataract ?

A – Anterior seg inflamn

 _   Glaucoma [ Liquefied  cortex escapes & clogs the TM]

             ENDOPHTHALMITIS

DEF-

Inflammation of inner layers of the eye resulting from intraocular colonization of infectious agents & manifesting as exudation in the vitreous cavity.

ORGANISMS-

A] EXOGENOUS-

    When infectious agents reach the vit cavity across an opening in the ocular coat.

1.   Acute postoper- [1-7 days after surgery ]-

            Staph epidermidis [MC]

            Staph aureus

            Strepto

            Gm –ve- Pseudomonas

                -Proteus

                -kleb

                -H. inf

                -E. coli

                -Bacillus

                -Enterobacteriaceae

             Anaerobes

2. Delayed onset [wks –mo/yrs after surg]

-Fungi-

*  Aspergillus

*  Fusarium

*  Candida

*   Cephalosporium

*  Penicillium

-Bacteria-

*  Propionibacterium acne[equatorial capsular plaque-classic finding]

*  S. epider

*  Corynebacterium

*  Actinomyces

3. Post-Traumatic-

            Bacillus

            Staph epider

            Strepto

            Fusarium

            Mixed flora are common

B] ENDOGENOUS –

   When infectious agents reach the vit by haematogenous dissemination

*  Strep

*  Staph aureus

*  Bacillus cereus

*  N. meningitides

*  H.inf

*  Mucor

*  Candida

POST –SURGICAL ENDO

Surgical factors-

1.  Type of IOL-

  -Bacteria adhere strongly to hydrophobic IOL & hydrophilic                                                             -    surf repels them

   -Silicone attracts bact

   -Fluorine is a superior coating than heparin for PMMA

2.PC tear

3. Aqueous is antibact whereas vit is a good culture medium

4. Temporal incisions carry more risk [lack of protection from lid & conj]

Propionibacterium acne-

-White capsular plaque composed of sequestered  collection of org inside the capsular bag.

-Precipitated by yag c’tomy which releases sequestered org from PC into vit

- Rx- Total capsulectomy + IOL explantation to eradicate colonies of P. acnes

-Antibiotic of choice- Vancomycin

BLEB RELATED ENDO-

-High risk with- Thin walled blebs

                       -use of antimetab

                       -inferior limbus blebs

-It is imp to diff blebitis from end-in the former infection is confined to the bleb & AC & prognosis is good

-Org- Strepto & H influenzea [ penetrate intact conj easily]

Severity of end is graded as Severe & not severe

SEVERE-

1. Inaccurate PR
2. RAPD
3. No fundal glow
4. Limbal ring abscess
5. No response to intravitreal antibiotics

POST-Sx FUNGAL ENDOPHTHALMITIS-

C/F- Blurring of vision

    -Floaters

    -AC- Fixed hypopyon & a fibrinous mesh like exudation

   -Vitreous- Snow-balls & fluffy opacities

Imp considerations-

   - Prior to an intravitreal injection,any infected suture or  suture abscess should be removed.

-pay attention to wound integrity & status of lens which decides the site of entry.In aphakia with a broken vitreous phas, a translimbal route may be employed

-If there is vitreous herniation or incarceration in the wound,then a limited anterior V’tomy  + wound revision should be planned along IV inj

-Also rule out rise in IOP  & pre-existing RD or choroidal det

STERILE ENDO-

Results from-

1.Retained lens matter

2.Chem. Sterilization

3.Toxicity of residual monomers on PMMA IOL

4.Mechanical irritation of iris & CB by the lens

AETIOLOGY-

A] INFECTIVE-

1)  EXOGENOUS-3 times MC

*  Penetrating inj

*  IO surgery

*  Wound leak / bleb inf

*  Perforating cor ulcer

2)ENDOGENOUS-

Septic emboli from –Endocarditis

                         -Otitis media

                         -Meningitis

Seen mainly in immunocompromised subjects-METASTATIC ENDOPHTHALMITIS-occurs d/t hematogenous spread of infective org to the eye.

Predisposing factors-

1. prolonged antibiotic

2. abdominal Sx

3. Prolonged hyperalimentation

4.  Indwelling intravenous catheters

5. Hematological malignancies

6. Pulmonary & renal dis

7.Uncontrolled DM

8. IV drug abusers

9. AIDS

10. Neutropenia

11.Prolonged steroid & immunosuppressant for organ transplant & bone marrow transplant

12. Contaminated IV dextrose infusion

Causative agents-

* Candida albicans-MC

*  Aspergillus (A.fumigatus & A.flavus)

*  Histoplasmosis

*  Coccidiodomicosis

*  Cryptococcus

*  Fusarium

*  Blastomyces

* Sporothrix

*  Mucormycosis

C/F-Pain,redness,floaters,discharge & DOV

Candidiasis-

-Lesions are present in the retinal periphery and hence extensive disease may present without causing much symptoms

-Focal chorioretinitis

-‘Puff balls’ in vitreous

-Cotton –white lesion ‘string of pearl’ due to extension of lesion into the vit

Aspergillosis-

Lesions involve the macula & are highly symptomatic

-Chorioretinal lesions are more confluent with indistinct margins

D/D-

-Bacterial endogen endo

-ARN

-PORN

-CMV Retinitis

-Ruptured cysticercosis

-Toxoplasmosis

Rx-

-Yeast like- oral fluconazole

-Aspergillus-Itraconazole

-New drug- Voriconazole-oral,intravenous-200mg/d or intravenous

Prognosis-

Aspergillus has poor outcome as compared to candida

B]  TOXIC [STERILE]-

*  Retained IOFB [copper]

*  Foll IOL implant

*  Toxic reac to chem adherent to instruments, foll chem sterilization

*  Necrosis  of IO tum

*  Phacoanaphylactic uveitis

C/F-

-Cardinal features-Pain

                            -Lid edema

                            -DOV

-Systemic features- Fever

                            -Headache

                            -Vomiting

-Signs- V/A- Less than anticipated & may be HM or only PL

         -Lid edema

         -Intense ciliary & conjunctival congestion [ VIVA]

         -Chemosis

         - Cornea-varies from clear cor to Cloudy & edematous cor

                       -Ring abscess

                       -Cor melting

                       -Suture abscess

                       -Wound dehiscence

         -AC- KPS & Flare

                -Frankly fibrinous

                -hypopyon-most cardinal sign

         -Iris- pattern lost,boggy & muddy

                -Posterior synechiae

        - Pupillary light reaction- absent or sluggish

        -Pupillary membrane

         -Vitreous- Purulent

                        -Yellow reflex

        -IOP –usually on lower side

Clarity of media is graded by EVS as-

Grade 1. More than 20/4o [6/12] view of retina

2. Second order retinal Vs visible
3. Some Vs visible but not 2nd order
4. no retinal Vs visible
5. No red reflex

         

COMPLICATIONS-

• Panophthalmitis- Inv of Tenon’s capsule→ painful & limited OM

-Proptosis

-Orbital cellulites

-Cavernous sinus thrombosis

-meningitis

-Brain abscess

- Sev cases → Cyclitic membrane→ destruction of ciliary processes→ fall in IOP→ Globe shrinkage

-Pus  bursts thru the wall of  the globe behind the limbus→Pain subsides

- Not likely to set up sympathetic ophthalmitis

.

INVESTIGATIONS

1. Lid margin & conj swab
2. AC Tap
3. Vitreous Tap
4. USG
5. Complete blood count

1. AC TAP-

-Topical anaesthesia

-With a 30 gauge needle [26G if thick pus] 0.1ml Aq is aspirated

2. VITREOUS TAP-

-26 G needle is inserted thru  the pars plana [3mm post to limbus-pseudophakia /aphakia & 4mm in phakic eyes]

-Tip of the needle shud be visible thru the pupil

-0.2 ml of vit is aspirated

3.VITREOUS BIOPSY-

Adv-1.  Enables an adequate vol of sample

      2.    Prevents vitreous traction by cutting the strands rather  than pulling on them

Procedure-.

* The suction line on the vitreous cutter is replaced by a shorter tubing with tuberculin syringe at one end to enable suction

* Vitreous cutter is placed in the anterior vit & cutting is actuated.

* Simultaneously the piston is withdrawn to induce suction.

* 0.2 – 0.3 ml of sample is aspirated

AC & vitreous samples are directly inoculated onto-

1. Blood agar plate

2 Chocolate agar plate [37 deg C in CO2]

3.Sabouroid’s med [25deg C]

4. Thioglycolate-anaerobes [37 deg C]
5. Brain heart infusion broth

Transferred to the lab for microbio study.

But if immediate processing facilities are not available→innoculate the specimen into transport med such as-Robertson’s cooked meat broth which can be stored at room temp & transfer to the lab

Microbiological study-

1.Gram’s stain

2 Giemsa’s stain

3 KOH

4.Calcoflour stain [if fungus is strongly suspected]

Laboratory confirmed growth is defined as-

1] Atleast semiconfluent growth on solid media

2] Any growth on more than or equal to 2 media

3] Growth on one media + positive gram stain

   OBJECTIVES IN ENDO Rx

PRIMARY-

1. Control /eradicate infection
2. Manage complications
3. restoration of vision

SECONDARY-

1. Symptomatic relief
2. prevent panophthalmitis
3. maintain globe integrity

T/T-

A]  TOPICAL ANTIBIOTICS-

According to EVS Vancomycin ( 50mg/ml) & Amikacin ( 20mg/ml) are recommended

Fortified cefazolin [5%]  OR  Vancomycin [5%]

                                       +              

              Gentamycin[1.3%]  OR Amikacin [1.3%]

See cor for fortified drug prep

B]  CYCLOPLEGIC-

    Atropine E/O 1 % TDS

C] INTRAVITREAL  ANTIBIOTICS-

-  Injected after taking a 0.2-0.3 ml vit aspirate for preparing smears & cultures

AMIKACIN      [0.4 mg /0.1ml]

[Amikacin covers gm –ve]                      

                           +

CEFTRIAXONE  OR  VANCOMYCIN

  [2mg / 0.1 ml]              [1mg / 0.1ml]

                         +        [vanco covers gm +ve]

DEXAMETHASONE [0.4 mg /0.1ml]- optional

ADV-

Reduce tissue damage by inhibiting arachidonic acid metabolism

DISADV-

Reduce the ability of eye to sterilize the inoculum of microorganisms

Gentamicin should be avoided as it causes macular infarction & shows high drug resistance

If fungus suspected- IV AMPHOTERICIN-B [5μg /0.1ml] without steroids

INTRAVITREAL DRUG PREPARATION-spot

1. VANCOMYCIN-

*  1000µg [1mg] in 0.1ml

-500mg vanco + 10ml SW→50mg in 1ml & hence 10mg in 0.2ml

-withdraw 0.2ml & dilute with 0.8ml SW

-This will give a strength of 10mg in 1ml & hence 1mg in 0.1ml

In simple way-

500 mg   -    10ml

50mg      -    1ml

10mg      -     0.2ml

                      +

                    0.8ml

 10mg   -    1ml

1mg       -    0.1ml

CEFTAZIDIME-2.25mg in 0.1ml

500mg Cef  - 2ml SW

250mg [active ingredient-225mg]       -1ml

25 mg  [22.5mg]        - 0.1ml

0.1ml + 0.9ml = 25 mg [22.5mg] in 1ml

Hence 2.25mg in 0.1ml

CEFAZOLIN-2.25mg in 0.1ml

Same as above

AMIKACIN-400µg [ or0. 4mg ]  in 0.1ml

-Available as 100mg in 2ml vial

-50mg  - 1 ml

10mg -  0.2 mlSW

             +

            2.3ml SW

This gives 10 mg in 2.5 ml

-Hence 400µg in 0.1ml

GENTAMICIN-200 µg  [ or 0.2 mg ] in 0.1ml

-Available as 80 mg in 2ml vial

40mg in 1ml

4mg in  0.1mlSW

              +

           1.9ml SW

This gives 4mg in 2ml

                  2mg in 1ml

                 0.2mg in 0.1ml

AMPHOTERICIN-B-5µg in 0.1ml

-50mg Ampho +  10ml of 5 % dextrose

-5mg in 1ml

-500µg in 0.1ml

                 +

                9.9ml

This gives 500µg in 10ml

-50µg in 1ml

-5µg in 0.1ml

D] SUBCONJUNCTIVAL –

*  Amikacin-25mg/ 0.5 ml

*  Vancomycin -25mg /0.5ml

*   Ceftriaxone 100mg / 0.5ml

*  Dexamethasone 6mg/ 0.25ml

COMPLICATIONS OF INTRAVITREAL-

1. Elevated IOP

2. Intraocular h’age

3. Hyphaema

4. Drug induced retinal toxicity

5. RD

E] Topical cycloplegics-atropine 1% E/O TDS

   -Relieve ciliary spasm

   -prevent synehiae formation

   -enable better clinical evaluation

F] Topical Timolol 0.5% BD

   Oral acetazolamide 250 mg qid  for rise in IOP

G]  PARS PLANA VITRECTOMY- immediately

  -If  V/A PL + or worse

                  OR

  No response to IV antibiotics within 48 hrs

ADVANTAGES OF PPV-

1. Decrease the toxic & inflammatory load
2. Provide adequate undiluted specimen for culture studies
3. Increase antibiotic concentration
4. Remove media opacity
5. Rapid visual recovery

CARDINAL PRINCIPLES OF PPV-

1. Use maximal cutting rate
2. Minimal suction
3. Do not attempt to induce a PVD if it is not already present

F] Eye cannot be saved or NO PL→ EVISCERATION with Frill excision [Collar of sclera is left around ON to prevent spread of inf up the ON sheath giving rise to meningitis]

- - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - -

PARSONS-

* Lens diam- 8.8-9.2mm

* Weight at birth-65mg & at 80 yrs-258mg

    * Thickest at the anterior pre-equatorial region

* Thinnest at the posterior pole

*  3 Factors occur in cataract formn-

1. Hydration
2. Denaturation of lens proteins
3. Slow sclerosis

Soft cataract- Wen hydration is predominant

Hard cataract-Wen slow sclerosis is predominant

*  Snowflake cat- Juvenile DM, Down’s syn

* Christmas tree cat- Dystrophia myotonica

* Shield cat- Atopic dermatitis

*  Flower / rosette cat – trauma

*  Sunflower cat- Copper toxicity

Drugs causing cat-

1.Steroids

2. Anticholinesterases

3. Chlorpromazine

4.Busulphan

5.Chloroquine

6.Amiodarone

Copper, iron gold

SECOND SIGHT-

In nuclear cat, Change in refractive index of of lens causes index myopia thus improving near vision

COMPLICATED CATARACT-[j-02]

1. Inflam-

 -Iridocyclitis

 - pars planitis

 -Choroiditis

 - Endophthalm

 -Hypopyon CU

2. Deg-

-RP

-Myopic chorioret deg

3. RD

4. glaucoma

5. IO tum- RB

              - Malignant melanoma

Characterised by- Breadcrumb appearance & polychromatic luster

                 PAEDIATRIC CATARACT-case

Read from notes

          IOL  IN  CHILDREN

IDEAL LENS-

1. Min impact on ocular tiss
2. Loops shud not retain elasticity
3. Loops shud not compress the angle or sulcus
4. Lens shud not move in the eye wen rubbed vigorously

TIMING OF SURGERY-

A] BILATERAL  - DENSE→ 6 wks of age or before 3mo

                             -PARTIAL→monitor lens opacity & visual function & intervene later

Sx on the two eyes should be separated by 2weeks for childn < 2yrs & 1mo for childn > 2yrs

B] UNILATERAL-DENSE→urgent surg within days f/b aggressive t/t.If detected after 16 wks of age then surg is inadvisable as amblyopia is refractory.

                           -PARTIAL→ observe

                                               -Pupillary dilatation

                                               -part-time contralateral occlusion

What surgery you will do?

Child < 3 years→ Cataract extraction + Ant v’tomy + PPC

Child > 3 years→ Cat extraction + Ant v’tomy + PPC + PCIOL

SELECTION OF IOL-

Best material- PMMA & foldable acrylic lenses

    Ideal dia-10.5-12mm

IOL POWER-< 2yrs-do biometry & undercorrect by 20 % [as myopic shift occurs later]

   

AXIAL LENGTH	IOL POWER
17mm	25D
18mm	24D
19mm	23D
20mm	21D
21mm	19D

2-8 yrs-Do biometry & undercorrect by 10 %

SURGERY-

INDICATIONS-

 1.Visually significant cataract [ > 3mm]

2.Dense nuc cat

3.cat obstructing fundal view

     .4.Cat preventing refraction

 5.C/L cat removed

 6.Strabismus

 7.Nystagmus

IOL IMPLANTATION-

A] CAPSULAR / IN THE BAG FIXATION-

*   more physiological but diff

*   2-8 yr old

*   Sequesters the implant away from the vascularised tiss

*   Cap fixation has been strongly recommended

B] CILIARY SULCUS FIXATION-

*Neonates & infants

*  ADV-Easier to insert

           -Easy to remove later if exchange needed

*  DISADV- Pupillary capture & IOL decentration

            -

PROCEDURE-

-Cataract aspiration + Prim post capsulectomy + Ant vitrectomy

-Ped cat are soft.So phaco Power is rarely needed

-Lens cortex & nucleus are easily aspirated with an irrigation/aspiration  or v’tomy handpiece

-PPC prevents PCO

COMPLICATIONS

A] INTRAOPER-

1.AC collapse

2. Iris prolapse

3.Pupil constricts on inj to iris

B] IMMED PO

1.Ant uveitis

2.rise inIOP

3.Iris incarceration

4. Endoph

C] LATE-

1. IOL dislocation

2.Chr iritis

3.Glauc

4. RD

SECONDARY IOL-

• When great myopic shift occurs
• When myopic shift more than 7D compared to fellow eye occurs

                VISCOELASTICS-spot

PHYSICAL PROPERTIES-

1. Optical-transparent

               -RI similar to aq

               -colour slightly diff from aq

2. Lower surface tension & lower contact angle

  Therefore  better ability to coat

2.Viscosity

3.Elasticity-Should regain its shape after being forced out thru a narrow & fine needle

4. Slow velocity

5. Cohesiveness

6. Protective to endo,separate tiss & maintain the eye shape.

CHEMICAL PROPERTIES

1. Inert
2. Iso-osmotic
3. Free of particulate matter
4. Non-pyrogenic
5. Non-antigenic
6. Non-toxic
7. Non-allergic
8. Resorbed without inflamn
9. Hydrophyllic

10.Dilutable

11. No interference with wound healing

SODIUM HYALURONATE-

1% Healon

Source- Rooster comb

          -Umbilical cord

          -strepto culture

Adv-

1. non-inflam
2. Non-allergic
3. Non-carcinogenic
4. Does not support bact growth
5. Can be stored at room temp for 1mo
6. PO rise inIOP less

Disadv-

1. autoclave not possible
2. rise in IOP
3. poor coatability
4. crystalline deposits on IOL

CHONDROITIN SULPHATE- Viscoat

20% & 50%

Source- Shark cartilage

          -Genetic engineering

Adv- better viscosity

Disadv-

1. Large bore cannula reqd
2. Poor in separating tiss d/t low viscosity

METHYL CELLULOSE

2% HPMC

Hydroxy propyl methyl cellulose

Source- Raw wood pulp

          -cotton

Adv-

1. Low  cost
2. Easy manufacturing
3. Autoclavable
4. Can be diluted & is hy drophilic-so can be easily irrigated from the eye

Disadv-req large bore cannula

POLYACRYLAMIDE

0.5%

Synthetic

Adv-

1. does not req refrigeration
2. low  contact angle-more coatability

Disadv- long elimination time from the body[ spleen & liver]

COLLAGEN-

2% type I collagen

Source- human placenta

May cause allergy as it is a protein

CELLUGEL

Synthetic

Adv-

1. autoclavable
2. No refrigeration
3. can be injected with a 25 G cannula

Newer-Poly TEGMA-40%

         -Poly GLYMA

USES OF VISCO-

1.cat Sx

-protects cor epith

-Control of capillary ooze

-AC maintainence

-Controlled ant C’tomy

-nucleus delivery by viscoexpression

-atraumatic intro of phaco probe & other instrum into AC

-Rx of expulsive h’age-forces IO contents back so that sutures can be placed comfortably

-coating of IOL

2.CME- restores IOP & prev edema

3. Glaucoma-1. G’tomy

                    2. trab

                    3. cyclodialysis

4.KP

5.retinal surg-replaces dis vit

                    -pushes detached ret closer to choroids

6.Trauma-sorting out tiss

              -restoring nml shape

              -raising IOP

7.Membrane sx

8.NLD block-maintain patency

S/E-

1. blockage of orifice
2. Retroirideal inj→ iris prolapse
3. reduced thermal convection
4. prev rapid spread of drugs in AC
5. rise in IOP

Diff from vitreous-

-vit does not stick to sponge or tiss so can be wiped away

-while removing visco,iris & pupil do not change shape whereas while removing  vit,pupil peaks & iris moves

COMPLICATIONS OF CATARACT SX

INTRAOPERATIVE-

1.INCISION RELATED-

-Superficial dissection of tunnel→ button-holing

-deep dissection→Premature entry

-deep groove→ Scleral disinsertion

2. DM DETACHMENT-

Cause- Sharp instrument used for entry

          -inadvertent fld bet DM & stroma

RX- -Inject air in AC & reposit the detached DM in pos

       -Inject SF6 OR C3F8 to reposit the detached DM

       -Suture with 10-0 nylon passed thru incision or peripheral cor-AC-det DM,stroma & epith—suture ends are tied on the external surf of cor & knots are buried

3. IRIDODIALYSIS-

-if cosmetically & optically insignificant→ leave it

-If extensive→ suture the iris to its root

4. RHEXIS RELATED-

-Peripheral extension of rhexis may go upto the equator or PC

-Small rhexis→ PC Tear & nu drop during hydrodissection & also predisposes to zonular dehiscence

-Large rhexis→ problem in placement of IOL in the bag

-Eccentric rhexis→ decentration later

5.PCR-Riskfactors-

                              1. small pupil

                              2.hard nuc

                              3.PXFs

                             4.deep seated eyeball

                            5.prev trauma

SIGNS-1. Sudden deepening of AC-1st sign

            2. Momentary pupillary dilation

            3.Nu falls away & does not come towards the phaco tip

            4. Vit may be aspirated into the phaco tip

            5. Torn capsule visible

            6. Vit in AC

Q- How will u manage PCR?

-Lower the infusion bottle height

-Full occlusion of aspiration port

-Use min phaco power to avoid further damage to capsule & vit aspiration

-Inject visco post & ant to the frag so as to float it anteriorly & to cushion the cor endo

-Once it is safely repositioned into the AC ,the choice is to convert to ECCE or to continue with phaco

-ECCE→ Enlarge the incision & extract the nu

-Phaco→ If the frag is small & the PCR is also small,cover the PC with visco & complete the phaco with low phaco power .

-If the nuc frag is not visible & surgeon is not experienced with pars plana Sx → Do an ant vitrectomy with guillotine vit cutter.Remove peripheral cortical matter.

-Retreival of frag from the deep vit is not recommended.Posteriorly dislocated frag should be approached within 1-2 weeks by a VR surgeon via a PPV

-Retained lens matter→elev IOP

                                 →Inflamn

                                 →cor edema

-IOL insertion-

a) in the bag-

For small,central rent with well-defined ant capsular margins.Haptics should be oriented away from the rent to prevent IOL migration into  the vit.Insert the lens gently to avoid extension of the rent.

b) ciliary sulcus-

For- PCR > 4-5 mm length

     -Extensive zonular loss

     -inadequate capsular bag support

Ciliary sulcus is opened with visco,iris is retracted in all quad to assess the peripheral capsule & zonules,IOL is inserted with its haptics away from the PCR & placed in areas of intact zonules & cap.OR if  ant C’rhexis is intact IOL is placed in the sulcus with capture of the optic thru the rhexis

c) Scleral fixated- Done if . 4-5 clock hrs capsule or zonule loss occurs,cil sulcus may be inadequate for lens stability

d) AC IOL-

Complications- glauc

                       -PAS

                       -chr uveitis

                       -BK

6. VITREOUS LOSS-

Complications of VL-

1.Updrawn pupil

2.Uveitis

3.Vit touch

4.Vit wick sy

5.Sec gluac

6.Post dislocation of IOL

7.RD

8.CME

Rx OF VL-

Ant v’tomy

7. NUCLEUS DROP-

Risk factors-

1. PCR
2. Post polar cat predisposes to PC dehiscence

Timing of Sx-

Controversial-some say-1st week as later removal is asstd with poorer visual outcome.

Some say-Sx should be deferred for 2-3 weeks.First treat uveitis & control raised IOP medically.The lens material becomes hydrated & softer which facilitates removal with a cutter alone

Tech-Treat uveitis & control IOP first & refer to a VR surgeon

-PPV & Frag removal with a vit cutter.

-Hard frag are floated clear of the retina with PFCL & either emulsified with the fragmetome in the mid-vit cavity or delivered via a corneal incision or scleral pocket

                                  OR

Hard frag can be crushed bet endoilluminator & vit cutter  & then forced  & fed into the cutting port

Complications of nuc drop-

1. Glauc
2. Chr uveitis
3. RD
4. CME

8 .EXPULSIVE  HAEMORRHAGE OR SUPRACHOROIDAL H’AGE

Def- Bleed into the suprachoroidal space resulting in extrusion of IO contents or apposition of ret surf

ECCE > phaco

-Source of bleeding-

Long & short post ciliary A

Risk factors-

1. Adv age
2. Glauc
3. Increased axial length
4. CV dis
5. VL

Signs-

1. Shallow AC
2. Increased IOP
3. Iris prolapse
4. Vitreous extrusion
5. Loss of red refex & a dark mound behind the pupil
6. Extrusion of all the IO contents

Rx-Immediate t/t-

1. Close the incision
2. Topical & sys steroids
3. Posterior sclerotomy  has been advised but it exacerbates bleeding

Susequent t/t-

1. B-scan –to assess severity
2. Sx is performed 7-14 days later when bld clot has liquefied.Bld is drained,PPV & air –fld exchange is done

EARLY PO COMPLICATIONS-

1. HYPHAEMA-

Site of bleeding-incision or iris

Bleeding can be minimized by-

1.Cautery

2.Adequate internal cor valve to prevent scleral bld from entering the AC

3.clear cor incision

IO bleeding can be stopped by-

1. Temporarily increasing the IOP  with BSS or visco
2. Intracameral diluted sol of preservative free

epinephrine (adrenaline) 1: 5000

3. Direct cautery of the blding V

Hyphaema  [late] is encountered in UGH syn d/t chaffing of the IOL against the iris or CB.seen with sulcus fixated IOL

Complications-

Corneal bld stain

Rise in IOP

2.IRIS PROLAPSE-

Cause-inadequate wound incision-

• a phaco incision with a peripheral point of entry into the AC
• leaking incision
• Inadeq ECCE suturing
• Coughing & straining

C/F-

• Prolapsed uveal tiss visible on the ocular surf
• AC is shallow in the area of incision
• Pupil peaked towards the prolapse

Complications-

• Defective wd healing
• Astigmatism
• Epith ingrowth
• Chr ant uveitis
• CME
• Endo

Rx-small prolapse < 24hrs & viable iris- reposited back & wound sutured

Large prolapse of long duration needs abscission & wound suturing.

3. STRIATE KP-

Endothelial damage→ mild cor edema with DM folds

Rx –usually disappears within a week

-Mod-sev KP- hypertonic saline drops (5% NaCl) + Steroids

4.FLAT / SHALLOW AC-

Etio-

1. Leaking incision
2. Choroidal det
3. Pupillary block
4. Ciliary block
5. Suprachoroidal h’age

Complications-

1. PAS
2. Chr angle closure glauc
3. Endo cell los & cor edema

Rx-

1. Cycloplegia
2. pressure patch
3. Aq suppressants-Topical B blocker & oral CAI
4. SBCL
5. tissue adhesive to seal the incision

If no improvement occurs ny 24-48 hrs

6.AC reformation & repair of incision

5.ENDOPHTHALMITIS-notes

6.CORNEAL  EDEMA-

Cause-

1. Mechanical trauma

2.Prolonged Sx

3.Inflamn

4.Elev IOP

5.Toxic subst introd in AC

6.Small nuclear frag retained in the AC angle

Rx-

1.Topical hyperosmotic agents

2.Topical steroids

3. BCL

4.Cautery of epith & ant stroma

5.Gundersen conj flap / Amniotic memb graft

6.PTK

7.PK

Brown Mc lean syn-peripheral cor edema with a clear central cor.Common after ICCE.also seen iin ECCE & phaco

7. TASS SYN

Toxic anterior segment syn-Form of sterile ,non-infectious  endophthalmitis

Cause-

1. Irrigating sol
2. Subconj antibiotic inj
3. Skin cleansers containing chlorhexidine gluconate
4. Preservatives present in prediluted adrenaline 1:5000
5. Residual toxic material in reusable cannulas & or irrigating tubes

C/F-

• pain
• photophobia
• sev reduction of V/A
• Marked AC reaction-hypopyon
• Presents wihin 12-24 hrs ( acute endo-2-7days)

Diff from endoph-

• Diffuse limbus to limbus cor edema
• AC opacification
• Dilated ,irreg & non-reactive pupil
• Elev IOP

Rx-

Freq topical steroids & sys steroids

LATE POSTOPER  COMPLICATIONS-

1. CME-Irvine Gass syn

Increased perifoveal capillary permeability

Cause-

1.VM traction

2. excessive uv light exposure

3.PCR

4.VL

5. Iris prolapse

6.Transient / prolonged hypotony

7 Drugs-topical epinephrine & dipivefrine

           -latanoprost

8. ERM

9. DM

10. Malpositioned IOL-Iris tuck,cor touch,papillary capture,short AC IOL

A UV –filtering IOL reduces CME

C/F-presents at6-10 wks after Sx

• Unexplained visual loss
• Honey comb cystic spaces on O’scopy
• Petalloid appear on FFA
• OCT-cystic spaces
• Spontaneous resolution within 6 mo

Rx-

1. Topical indomethacin 1%  & ketorolac 0.5% TDS for 6 weeks
2. sub-tenon steroid
3. Intra-vit triamcinolone acetonide
4. Nd: YAG laser vitreolysis or surgical removal of vit adherence to the cat incision site to relieve the VMT
5. IOL exchange

2.DELAYED ONSET ENDOPHTHALMITIS-LENS

3. PSEUDOPHAKIC BULLOUS KP –cor-38

4.RD

Occurs within 6mo of cat Sx or foll post c’tomy

Risk factors-

Pre-oper-1. Axial myopia ( >25mm & >6D)

              2.Age< 50 yrs

              3.Lattice deg

              4. Prev ret tear or RD

              5. RD in fellow eye

              6. Family H/O RD

Surgeon must be more vigilant & examine peripheral fundus & treat asymptomatic breaks pre-operatively

Operative-

1. PCR
2. VL

Post-oper

Nd: YAG Capsulotomy ( should be delayed for 3-6 mo after cat Sx to allow post vit separation  & less disruption to Vitreoretinal surf)

5. EPITHELIAL INGROWTH-

Sheet of epith growing down from the surgical incision & covering the cor endo or iris surf.

Pathogenesis-Theories-

1. Epith cells are introd into the AC during Sx → adhere to IO struc & proliferate as a cellular memb
2. Sheet of epith from the ocular surf grows into the incision if it is not watertight & this memb proliferates onto the post cor surf & iris surf.

C/F-

• elev IOP( epith memb grows over the TM or epith cells clog the TM)
• Clumps of cells floating in the AC
• Retrocorneal memb with overlying cor edema
• Abnormal iris surf
• Pupillary distortion
• Diagnosis confirmed by applying argon laser burns to the memb or iris surf which ppears white if epith cells are present

Rx-

1. Cryotherapy
2. 5FU
3. Glauc valves

6 FIBROUS DOWNGROWTH-

Imperfect wound apposition→fibrous downgrowth into AC→ Sec glauc ,disorganization of ant seg→ phthsis bulbi

7.AFTER CATARACT-LENS-2

8 . APHAKIC & PSEUDOPHAKIC  GLAUCOMA- CASE

Early PO period-

1. Tight suturing→ distorts AC angle
2. Delayed re-formn of AC→PAS
3. Pupillary block by air or vit→ sec ACG
4. TM block by visco or vit→ sec OAG
5. Hyphaema & ac iridocyclitis
6. UGH synd-

Late PO Period-

1.Epith ingrowth

2.Fibrous downgrowth

3. PAS

Rx-

1. Early period- anti-glauc

                       -Cycloplegics

                       - laser PI

2. Late stages-Trab + anti-metabolites

                    -cyclocryotherapy

9 IOL –RELATED-

1)  UGH SYN-

-Uveitis –glaucoma-hyphaema

-seen with rigid AC IOL & closed loop IOL

Cause-

1.Inappropriate IOL size

2. Contact bet iol & vascular str or cor endo

3. Defects in implant manufacturing

4. PC IOL –Loops in contact withuveal tiss in the post chamber

Rx-

1. Topical anti-inflam  anti-glauc
2. IOL removal should be considered if it is threatening the retinal or cor funcn.

But this proc is very complicated d/t inflame scars in the angle.The surgeon may need to amputate the haptics from the optic & remove the lens piecemeal,rotating the haptic out of the synechial tunnels to minimize trauma to the eye.In some cases it is safer to leave portions of the haptics in place.

2. MALPOSITION OF IOL-

-Sunset syn-Inferior subluxation

-Sunrise syn-Sup  subluxation

-Lost lens syn-complete dislocation into the vit

-Windshield wiper syn-occurs when a very small IOL is placed vertically in the sulcus.In it the superior loop moves to the left & right with head movts

An IOL gets decentered when-

1. Asymmetric haptic placement,with one in the bag & one in the sulcus
2. Insufficient zonular or capsular support
3. Posterior capsular fibrosis
4. Capsular phimosis

3. PUPILLARY CAPTURE

Causes-

1. Synechia bet iris & underlying PC
2. Improper placement of IOL haptics
3. Shallowing of AC
4. Anterior displacement of PC IOL haptic due to placement of non-angulated IOL in ciliary sulcus,upside –down placement of an angulated IOL so that the IOL angles anteriorly or positive vit press behind the lens optic.
5. Placement of a posteriorly angulated PC IOL in the capsular bag → ↓ pup cap

C/F-

• glare
• photophobia
• chr uveitis
• unintended myopia
• monocular diplopia

RX-

1. Purely cosmetic issue. If asymptomatic→ left untreated
2. Mydriatics→ to free iris by pharmacologic manipulation of pupil
3. Sx- Free the iris,break the synechiae or reposit the IOL