Management of Cataract

Cataract, Types, Management, Treatment

1. By Kevin J Ambadan MANAGEMENT OF CATARACT

2. NON SURGICAL MANAGEMENT

3. TREATMENT OF THE CAUSE OF CATARACT Adequate control of diabetes mellitus , Removal of cataractogenic drugs such as corticosteroids , phenothiazenes and strong miotics Removal of irradiation (infrared or X-rays) Early and adequate treatment of ocular diseases like uveitis

4. MEASURES TO DELAY PROGRESSION Commercially available preparations containing iodide salts of calcium and potassium are being prescribed in abundance in early stages of cataract Vit E and aspirin also delays the process of cataractogenesis

5. MEASURES TO IMPROVE CATARACT IN THE PRESENCE OF INCIPIENT AND IMMATURE CATARACT Refraction should be corrected at frequent intervals Arrangement of illumination-patients with peripheral opacities brilliant illumination Use of dark goggles in patients with central opacities Mydriatics - 5%phenyephrine or 1% tropicamide b.i.d in affected eye

6. SURGICAL MANAGEMENT

7. INDICATIONS Visual improvement Medical indications: -Lens induced glaucoma - Phacoanaphylactic endophthalmitis -Retinal diseases like diabetic retinopathy or retinal detachment c) Cosmetic indication-to obtain black pupil

8. PREOPERATIVE EVALUATION

9. GENERAL MEDICAL EXAMINATION OF THE PATIENT OCULAR EXAMINATION The following information is essential before the patient is considered for surgery: RETINAL FUNCTION TESTS Light Perception Test for M arcus G unn pupillary response Projection of rays - Test for function of peripheral retina

10. Two light discrimination test - Macular function Maddox rod test Colour perception-macular function and optic nerve Entoptic visualisation -retinal function Laser interferometry Objective tests for evaluating retina-ultrasonic evaluation, ERG, EOG, VER and indirect ophthalmoscopy

11. SEARCH FOR LOCAL SOURCE OF INFECTION - to rule out conjunctival infection or lacrimal sac infection ANTERIOR SEGMENT EVALUATION IOP MEASURMENT - raised IOP needs priority management

12. PRE-OP MEDICATIONS AND PREPERATIONS TOPICAL ANTIBIOTICS - Tobramycin and Gentamicin QID for 3days before surgery PREPARATION OF THE EYE TO BE OPERATED CONSENT SCRUB BATH AND CARE OF HAIR DRUGS TO LOWER IOP - Acetazolamide 500mg stat 2hrs before surgery and Glycerol 60ml mixed with water 1hr before surgery DRUGS TO SUSTAIN DILATED PUPIL - AntiProstaglandin eye drops(Indomethacin)

13. ANAESTHESIA Cataract extraction can be performed under gen or local anaesthesia . Local is preferred.

14. SURGICAL TECHNIQUE FOR CATARACT EXTRACTION

15. INTRACAPSULAR CATARACT EXTRACTION T he entire cataractous lens along with the intact capsule is removed . Therefore weak and degenerated zonules are a pre-requisite for this method . Because of this reason, this technique cannot be employed in younger patients where zonules are strong . ICCE can be performed between 40-50 years of age by use of the enzyme alphachymotrypsin (which will dissolve the zonules ). Beyond 50 years of age usually there is no need of this enzyme.

16. INDICATION - Subluxated and dislocated lens SURGICAL STEPS OF ICCE TECHNIQUE: Superior rectus (bridle) suture Conjunctival flap Partial thickness groove/gutter Corneoscleral section Iridectomy

17. Methods of lens delivery Indian smith method Cryoextraction Capsule forceps method Irisophake method Wire vectis method Formation of Anterior Chamber Implantation of anterior chamber IOL(ACIOL ) Closure of incision- 5-7 interrupted sutures Conjunctival flap reposited Subconjunctival injection-dexamethasone 0.25ml and gentamicin 0.5ml given Patching of the eye

18. P assing of superior rectus suture F ornix based conjunctival flap P artial thickness groove C ompletion of corneoscleral section P eripheral iridectomy C ryolens extraction I nsertion of Kelman multiflex IOL in anterior chamber I nsertion of Kelman multiflex IOL in anterior chamber C orneo -scleral suturing

19. EXTRACAPSULAR CATARACT EXTRACTION Major portion of anterior capsule with epithelium , nucleus and cortex are removed; leaving behind intact posterior capsule. Indications: Presently, it is the surgery of choice for all types of adulthood as well as childhood cataracts unless contraindicated . Contraindications - S ubluxated and dislocated lens

20. Types of extracapsular cataract extraction a) Conventional E xtracapsular C ataract E xtraction (ECCE) b) Manual S mall I ncision C ataract S urgery ( SICS ), c) Phacoemulsification

21. C ONVENTIONAL ECCE Superior rectus (bridle) suture Conjunctival flap (fornix based) Partial thickness groove/gutter Corneoscleral section. Injection of viscoelastic substance in anterior chamber - 2% MethylCellulose or 1% Sodium Hyaluronate (Maintains anterior chamber and protects endothelium )

22. Anterior capsulotomy . Can-opener's technique Linear capsulotomy (Envelope technique ) Continuous circular capsulorrhexis (CCC ) Removal of anterior capsule Completion of corneoscleral section Hydrodissection ( ie ., seperation of capsule from cortex by injecting fluid between the two) - Balanced salt solution injected under peripheral part of ant capsule to separate corticonuclear mass from the capsule

23. Removal of nucleus After hydrodissection the nucleus can be removed by any of the following techniques : Pressure and counter-pressure method Irrigating wire vectis technique Aspiration of the cortex Implantation of IOL Closure of the incision - 3-5 interrupted sutures Removal of viscoelastic substance Conjunctival flap is reposited and secured Subconjunctival injection Patching of eye

24. A nterior capsulotomy Can Opener's technique Removal of anterior capsule C ompletion of corneo -scleral section R emoval of nucleus (pressure and counter-pressure method ) Aspiration of cortex I nsertion of inferior haptic of posterior chamber IOL I nsertion of superior haptic of PCIOL D ialing of the IOL C orneo -scleral suturing

25. MANUAL SMALL INCISION CATARACT SURGERY Superior rectus suture Conjunctival flap and exposure of sclera Haemostasis Sclero corneal tunnel incision: External scleral incision - 5.5mm to 7.5mm Sclero corneal tunnel - 1-1.5mm Internal corneal incision Side port entry

26. Anterior capsulotomy - can be can- openers,envelope or continuous circular capsulorrhexis (CCC) Hydrodissection Nuclear management a)prolapse of nucleus into ant chamber b)delivery of nucleus through corneoscleral tunnel Aspiration of cortex IOL implantation Removal of viscoelastic material Wound closure

27. Superior rectus bridle suture Conjunctival flap and exposure of sclera C, D & E. External Scleral incisions (straight, frown shaped, and chevron, respectively) part of tunnel incision Sclero -corneal tunnel with crescent knife nternal corneal incision Side port entry A nterior capsulotomy -Large CCC Hydrodissection Prolapse of nucleus into anterior chamber Nucleus delivery with irrigating wire vectis Aspiration of cortex I nsertion of inferior haptic of posterior chamber IOL Insertion of superior haptic of PCIOL Dialing of the IOL Reposition and anchoring of conjunctival flap.

28. PHACOEMULSIFICATION Corneoscleral incision-very small 3mm Continuous curvilinear capsulorrhexis of 4-6mm Hydrodissection Nucleus is emulsified and aspirated Remaining cortical lens matter is aspirated IOL Implantation Removal of viscoelastic material Wound closure

29. Continuous curvilinear capsulorrhexis Hydrodissection ; Hydrodelineation D & E. Nucleus emulsification by divide and conquer technique F. Aspiration of cortex.

30. SURGICAL TECHNIQUE FOR ECCE FOR CHILDHOOD CATARACT Surgical techniques employed for childhood cataract are essentially of two types : Irrigation and aspiration of lens matter Lensectomy 1 . Irrigation and aspiration of lens matter i. Conventional ECCE technique ii. Corneo -scleral tunnel techniques which include : Manual SICS technique Phaco -aspiration technique

31. SURGICAL STEPS OF IRRIGATION AND ASPIRATION OF LENS MATTER BY CORNEOSCLERAL TUNNEL INCISION 1-5. I nitial steps upto making of side port entry are same as SICS 6. Anterior capsulorhexis of about 5mm size 7. Irrigation and aspiration of lens matter 8. Posterior capsulorhexis of about 3-4 mm size is recommended in children to avoid posterior capsule opacification 9. Anterior vitrectomy 10. Implantation of IOL after inflating capsular bag with viscoelastic substance-heparin or flourine coated PMMA IOL preferred in children. 11. Removal of viscoelastic substance is done 12. Wound closure.

32. LENSECTOMY In this operation most of the lens including anterior and posterior capsule along with anterior vitreous are removed with the help of a vitreous cutter, infusion and suction machine . Childhood cataracts, both congenital/developmental and acquired, being soft are easily dealt with this procedure especially in very young children (less than 2 years of age) in which primary IOL implantation is not planned. L ensectomy in children is performed under general anaesthesia

33. INTRAOCULAR LENS IMPLANTATION Presently, intraocular lens (IOL) implantation is the method of choice for correcting aphakia . Types of intraocular lenses: The commonly used material for their manufacture of lens is polymethylmethacrylate (PMMA). The major classes of IOLs based on the method of fixation in the eye are as follows: Anterior chamber IOL Lie entirely in front of the iris and are supported in the angle of anterior chamber. ACIOL can be inserted after ICCE or ECCE. N ot very popular due to comparatively higher incidence of bullous keratopathy . When indicated, ‘ Kelman multiflex ’ type of ACIOL is used commonly.

34. 2. Iris-supported lenses These lenses are fixed on the iris with the help of sutures, loops or claws. H igh incidence of postoperative complications. Example of iris supported lens is Singh and Worst’s iris claw lens . 3. Posterior chamber lenses PCIOLs rest entirely behind the iris . They may be supported by the ciliary sulcus or the capsular bag. Commonly used model of PCIOLs is modified C-loop . Depending on the material of manufacturing, three types of PCIOLs are available: i. Rigid IOLs -made entirely from PMMA. ii. Foldable IOLs-made of silicone, acrylic, hydrogel and collamer . iii. Rollable IOLs are ultra thin IOLs-These are made of hydrogel .

35. Kelman multiflex Singh & Worst's iris claw lens Posterior chamber IOL (an anterior chamber IOL ) (modified C-loop type)

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