Complications of Complications of cataractcataract

Complications of Complications of CataractCataract

I. Lens Induced GlaucomaI. Lens Induced Glaucoma Cataract can give rise to secondary glaucoma in Cataract can give rise to secondary glaucoma in

following ways: following ways: Phacomorphic GlaucomaPhacomorphic Glaucoma: Lens may swell up : Lens may swell up

by absorbing fluid resulting in shallow anterior by absorbing fluid resulting in shallow anterior chamber (intumescent cataract). The angle may chamber (intumescent cataract). The angle may close blocking the trabecular meshwork and IOP close blocking the trabecular meshwork and IOP rises. A type of secondary angle closure rises. A type of secondary angle closure glaucoma. glaucoma.

Phacolytic GlaucomaPhacolytic Glaucoma: In hypermature stage : In hypermature stage the lens proteins leak out into the anterior the lens proteins leak out into the anterior chamber and are engulfed by macrophages. chamber and are engulfed by macrophages. These swollen macrophages clog the trabecular These swollen macrophages clog the trabecular meshwork leading to increase in IOP. A type of meshwork leading to increase in IOP. A type of secondary open angle glaucoma. secondary open angle glaucoma.

II. Lens Induced UveitisII. Lens Induced Uveitis Lens proteins are Lens proteins are sequestered antigenssequestered antigens

i.e. not exposed to the body’s immune i.e. not exposed to the body’s immune mechanisms during development. When mechanisms during development. When these leak into the anterior chamber they these leak into the anterior chamber they are treated as foreign, inciting immune are treated as foreign, inciting immune reaction. This results in anterior uveitis reaction. This results in anterior uveitis (inflammation involving iris and ciliary (inflammation involving iris and ciliary body). This is characterized by ciliary body). This is characterized by ciliary congestion and cells and flare in the congestion and cells and flare in the aqueous.aqueous.

III. Subluxation or Dislocation of LensIII. Subluxation or Dislocation of Lens In stage of hypermaturity the In stage of hypermaturity the

zonules of the lens may weaken and zonules of the lens may weaken and break. This leads to subluxation of break. This leads to subluxation of the lens (when at least some zonules the lens (when at least some zonules are still intact and a part of the lens are still intact and a part of the lens still lies in the patellar fossa) or still lies in the patellar fossa) or dislocation (when all zonules have dislocation (when all zonules have broken and no part of the lens lies in broken and no part of the lens lies in the patellar fossathe patellar fossa

Management of senile Management of senile cataractcataract

Indications Indications Visual improvement: when visual handicap Visual improvement: when visual handicap

becomes a significant deterrent to patient’s becomes a significant deterrent to patient’s usual lifestyle, surgery may be advisedusual lifestyle, surgery may be advised

Medical indications:Medical indications:- Lens induced glaucomaLens induced glaucoma- Phacoanaphylactic uveitisPhacoanaphylactic uveitis- Diabetic retinopathy or retinal detachment, Diabetic retinopathy or retinal detachment,

treatment of which is precluded due to lens treatment of which is precluded due to lens opacitiesopacities

Cosmetic Cosmetic

Preoperative evaluationPreoperative evaluation Pupillary ReflexesPupillary Reflexes: : - Special emphasis is placed on examining the Special emphasis is placed on examining the

pupillary signs as they may reveal presence of any pupillary signs as they may reveal presence of any visual pathway (afferent) or 3rd nerve (efferent) visual pathway (afferent) or 3rd nerve (efferent) disorder. This may affect the final visual outcome disorder. This may affect the final visual outcome e.g., afferent pupillary defect caused by optic e.g., afferent pupillary defect caused by optic atrophy may prognosticate poor visual result.atrophy may prognosticate poor visual result.

- Look for presence of Look for presence of Marcus-Gunn PupilMarcus-Gunn Pupil by by swinging flash light testswinging flash light test (i.e. rapidly shifting (i.e. rapidly shifting light from one eye to the other and back) one light from one eye to the other and back) one pupil pupil seemsseems to dilate in response to light whereas to dilate in response to light whereas the other constrictsthe other constricts. This denotes presence of a . This denotes presence of a relative afferent pupillary defectrelative afferent pupillary defect (RAPD) (RAPD) in in the eye whose pupil seems to dilate. Note that the the eye whose pupil seems to dilate. Note that the defect is partial and unequal in the two eyes. defect is partial and unequal in the two eyes.

Intraocular PressureIntraocular Pressure: Presence of lens : Presence of lens induced glaucoma or co-existent primary induced glaucoma or co-existent primary glaucoma should always be looked for glaucoma should always be looked for because increased IOP seriously affect the because increased IOP seriously affect the course and result of surgery. The IOP has to course and result of surgery. The IOP has to be well under control before the surgery for be well under control before the surgery for cataract is under-taken because not only cataract is under-taken because not only high pressure increases the risk of intra-high pressure increases the risk of intra-operative complications (viz. Vitreous loss, operative complications (viz. Vitreous loss, expulsive hemorrhage, etc.) but also may expulsive hemorrhage, etc.) but also may indicate poor visual prognosis indicate poor visual prognosis postoperatively.postoperatively.

Fundus ExaminationFundus Examination: Detailed retina : Detailed retina examination to rule out any pathology in examination to rule out any pathology in the posterior segment (behind the lens) the posterior segment (behind the lens) which may compromise visual outcome. which may compromise visual outcome.

Lacrimal SyringingLacrimal Syringing: It is important to : It is important to rule out any block or focus of infection in rule out any block or focus of infection in the lacrimal drainage system by doing the lacrimal drainage system by doing syringing. Focus of infection around the syringing. Focus of infection around the eye or even elsewhere in the body (e.g. eye or even elsewhere in the body (e.g. teeth, chest, urinary tract, etc.) increase teeth, chest, urinary tract, etc.) increase the risk of postoperative intraocular the risk of postoperative intraocular infection or infection or EndophthalmitisEndophthalmitis which can which can be devastating for vision. be devastating for vision.

Blood PressureBlood Pressure: Hypertension not only leads to : Hypertension not only leads to development of hypertensive retinopathy but also development of hypertensive retinopathy but also increases the chances of increases the chances of expulsive expulsive hemorrhagehemorrhage during surgery. In expulsive during surgery. In expulsive hemorrhage choroidal blood vessels rupture hemorrhage choroidal blood vessels rupture leading to bleeding between choroid and scleral, leading to bleeding between choroid and scleral, which pushes the choroid inwards and, if severe, which pushes the choroid inwards and, if severe, expelling the contents of the globe.expelling the contents of the globe.Hypertension must be well under control in the Hypertension must be well under control in the peri-operative period and the use of peri-operative period and the use of phenylepherine or adrenalin should be avoided. phenylepherine or adrenalin should be avoided. Anti-hypertensives must be added to the Anti-hypertensives must be added to the preoperative medication. preoperative medication.

Blood SugarBlood Sugar: Diabetes must be ruled out, : Diabetes must be ruled out, and if present must be controlled before and if present must be controlled before surgery. Diabetes can adversely affect any surgery. Diabetes can adversely affect any part of the eye especially the retina part of the eye especially the retina (diabetic retinopathy), wound healing is (diabetic retinopathy), wound healing is impaired and the risk of infection is impaired and the risk of infection is extremely high. Blood sugar should be extremely high. Blood sugar should be carefully monitored and kept in strict control carefully monitored and kept in strict control in the peri-operative period.in the peri-operative period.On the day of operation, however, the anti-On the day of operation, however, the anti-diabetics (hypoglycemics) are omitted to diabetics (hypoglycemics) are omitted to avoid the chance of severe hypoglycemia, avoid the chance of severe hypoglycemia, and are resumed from the first and are resumed from the first postoperative day. postoperative day.

General InvestigationGeneral Investigation: General body : General body check-up and some investigations like check-up and some investigations like hemoglobin, blood sugar, urine hemoglobin, blood sugar, urine examination, ECG and X-ray Chest examination, ECG and X-ray Chest (where required) should be done to rule (where required) should be done to rule out any significant systemic disorder. If out any significant systemic disorder. If any disease is detected patient should any disease is detected patient should be referred to concerned specialist for be referred to concerned specialist for appropriate treatment. appropriate treatment.

Macular Function TestsMacular Function Tests: These are done to : These are done to preoperatively assess the postoperative visual preoperatively assess the postoperative visual outcome (potential vision) based on which a outcome (potential vision) based on which a prognosis is given to the patient. These tests are: prognosis is given to the patient. These tests are:

With clear mediaWith clear media - Visual AcuityVisual Acuity: as tested by Snellen’s charts, if : as tested by Snellen’s charts, if

disproportionately less than what can be explained disproportionately less than what can be explained by the degree of cataract points to possibility of by the degree of cataract points to possibility of macular dysfunction.macular dysfunction.

- Color VisionColor Vision: Color appreciation and : Color appreciation and discrimination is best at macula because of discrimination is best at macula because of aggregation of cones. It can be deranged in any aggregation of cones. It can be deranged in any macular pathology.macular pathology.

- Photostress TestPhotostress Test: Visual acuity of patient is : Visual acuity of patient is determined and then his macula is dazzled by determined and then his macula is dazzled by bright light of a 3.5 Volt Ophthalmoscope. Then the bright light of a 3.5 Volt Ophthalmoscope. Then the time it takes for him to read one line above time it takes for him to read one line above previously read line on Snellen’s chart is noted. previously read line on Snellen’s chart is noted. Normal is 30 seconds but if it takes longer macular Normal is 30 seconds but if it takes longer macular function is abnormalfunction is abnormal

With opaque mediaWith opaque media

- Two Point Discrimination Test:Two Point Discrimination Test: A cardboard with 2 A cardboard with 2 pinholes 2 mm apart is placed 2 cm from patient’s pinholes 2 mm apart is placed 2 cm from patient’s eye and a light is shone 2 feet behind it. If patient eye and a light is shone 2 feet behind it. If patient reports seeing two lights then his macula is probably reports seeing two lights then his macula is probably normal.normal.

- Maddox Rod Test:Maddox Rod Test: Maddox Rod is a set of small Maddox Rod is a set of small high power red cylindrical lenses placed close to each high power red cylindrical lenses placed close to each other (or grooves cut in a red glass). A point source of other (or grooves cut in a red glass). A point source of white light seen through it appears as a white light seen through it appears as a red linered line. If . If macula is deranged the line would appear distorted, macula is deranged the line would appear distorted, irregular, broken or would just not be seen.irregular, broken or would just not be seen.

- Entoptic View:Entoptic View: Rubbing a lighted bare bulb Rubbing a lighted bare bulb of a torch pressed over closed eyelids of a torch pressed over closed eyelids makes individual’s own retinal (macular) makes individual’s own retinal (macular) blood vessels visible as dark red branches blood vessels visible as dark red branches of a tree against an orange background. In of a tree against an orange background. In macular pathology the vessels are either macular pathology the vessels are either not seen or black patches are seen not seen or black patches are seen scattered with the vessels. This test should scattered with the vessels. This test should first be done on the normal eye to first be done on the normal eye to demonstrate to patient what he is expected demonstrate to patient what he is expected to observe.to observe.

- Laser Interferometry:Laser Interferometry:

Two beams of plane polarized light are Two beams of plane polarized light are projected on to patient’s pupil. These projected on to patient’s pupil. These beams undergo beams undergo interferenceinterference and and form interference fringes of light and form interference fringes of light and dark bands behind patient’s lens. dark bands behind patient’s lens. Then the width of these fringes is Then the width of these fringes is reduced and the narrowest fringes reduced and the narrowest fringes seen by the patient are indicative of seen by the patient are indicative of his visual potential.his visual potential.

- Visually Evoked Response (VER), Visually Evoked Response (VER), Electroretinogram (ERG)Electroretinogram (ERG)

Ultrasonography (USG B-Scan): Ultrasonography (USG B-Scan): If If the cataract is advanced then the the cataract is advanced then the retina cannot be visualized by retina cannot be visualized by ophthalmoscopy, therefore, ophthalmoscopy, therefore, ultrasound (B-scan) is used to detect ultrasound (B-scan) is used to detect any structural abnormalities.any structural abnormalities.

Intraocular Lens Power Calculation:Intraocular Lens Power Calculation: The power of the intraocular lens to be implanted The power of the intraocular lens to be implanted

has to be calculated for each individual. Three has to be calculated for each individual. Three parameters are required as follows:parameters are required as follows:

- Keratometry (K):Keratometry (K): gives the refractive power of gives the refractive power of

the cornea (in diopters), using an instrument the cornea (in diopters), using an instrument called Keratometer.called Keratometer.

- Biometry or Axial Length of Globe (L):Biometry or Axial Length of Globe (L): The The distance (in mm) from the apex of cornea to the distance (in mm) from the apex of cornea to the posterior pole of the eye is measured by a special posterior pole of the eye is measured by a special ultrasound the A-Scan Biometer.ultrasound the A-Scan Biometer.

- A Constant (A):A Constant (A): It is supplied by the IOL It is supplied by the IOL manufacturer and it’s value depend on the design manufacturer and it’s value depend on the design of the lens and it’s intended location in the eye of the lens and it’s intended location in the eye (anterior or posterior chambers).(anterior or posterior chambers).

These values are put in a formula These values are put in a formula ((SRK FormulaSRK Formula) to get the power of ) to get the power of the lens to be implanted:the lens to be implanted:

IOL Power = A – 2.5L – 0.9 KIOL Power = A – 2.5L – 0.9 K

Preoperative PreparationPreoperative Preparation

Patient preferably admitted to the Patient preferably admitted to the hospital on previous evening (however, hospital on previous evening (however, surgery can also be done on daycare surgery can also be done on daycare basis). basis).

Informed consent is taken. Informed consent is taken. The eye-lashes of the eye to be operated The eye-lashes of the eye to be operated

are trimmed carefully and the eye is are trimmed carefully and the eye is cleaned with Povidone-Iodine 5 % cleaned with Povidone-Iodine 5 % solution, and marked. solution, and marked.

Antibiotic drops are instilled every 6 Antibiotic drops are instilled every 6 hourly hourly

Pupils are dilated by instillation of following eye-Pupils are dilated by instillation of following eye-drops starting about 2 hours before operation: drops starting about 2 hours before operation:

- Tropicamide 1% Tropicamide 1% - Phenylepherine 5-10%Phenylepherine 5-10% (avoided in (avoided in

hypertensive patient) hypertensive patient) - Flurbiprofen 0.3%Flurbiprofen 0.3% a non-steroidal anti- a non-steroidal anti-

inflammatory drug prevent release of inflammatory drug prevent release of prostaglandins during surgery thereby preventing prostaglandins during surgery thereby preventing intraoperative constriction of pupil that may be intraoperative constriction of pupil that may be caused by surgical trauma.caused by surgical trauma.These drops are instilled every 15 minutes.These drops are instilled every 15 minutes.

Other medications may be given as required e.g., Other medications may be given as required e.g., antiglaucoma drugs, antihypertensives, anti-antiglaucoma drugs, antihypertensives, anti-asthamatics, etc. But anti-diabetic drugs are asthamatics, etc. But anti-diabetic drugs are omitted on the day of surgery to prevent omitted on the day of surgery to prevent hypoglycaemia, and are resumed from the first hypoglycaemia, and are resumed from the first postoperative day. postoperative day.

AnesthesiaAnesthesia

Most cases of cataract are operated Most cases of cataract are operated under local anesthesia except in young under local anesthesia except in young children. The techniques used are: children. The techniques used are:

Retrobulbar anesthesia*- given in Retrobulbar anesthesia*- given in retrobulbar/intraconal space retrobulbar/intraconal space

Peribulbar anesthesia – given in Peribulbar anesthesia – given in peripheral spaceperipheral space

Facial nerve block* Facial nerve block* * These two are given in combination.* These two are given in combination.

The anesthetic agent used is a solution of following; The anesthetic agent used is a solution of following; Lignocaine or Xylocaine 2 %Lignocaine or Xylocaine 2 % which the main which the main

anesthetic agent anesthetic agent Bupivacaine 0.75 %Bupivacaine 0.75 % which has a prolonged which has a prolonged

duration of action and analgesia. It is used duration of action and analgesia. It is used primarily for increasing duration of action and for primarily for increasing duration of action and for postoperative analgesia. postoperative analgesia.

Adrenaline 1 in 200,000Adrenaline 1 in 200,000 leads to constriction of leads to constriction of blood vessels thereby decreasing absorption of blood vessels thereby decreasing absorption of anesthetics and thus prolonging duration of action anesthetics and thus prolonging duration of action and decreasing side effects. It should be avoided in and decreasing side effects. It should be avoided in hypertensive patients. hypertensive patients.

Hyaluronidase 7-15 IU per mLHyaluronidase 7-15 IU per mL is used to is used to promote diffusion of the anesthetic into the orbital promote diffusion of the anesthetic into the orbital tissues. tissues.

Choice of OperationChoice of Operation The operation of choice for cataract The operation of choice for cataract

is: is:

EExtra-xtra-CCapsular apsular CCataract ataract EExtraction with Posterior xtraction with Posterior Chamber Intraocular lens Chamber Intraocular lens ImplantationImplantation

Surgical proceduresSurgical procedures

Intracapsular cataract extractionIntracapsular cataract extraction Extracapsular cataract extractionExtracapsular cataract extraction- Conventional (limbal incision)Conventional (limbal incision)- Small incision cataract surgery (SICS) Small incision cataract surgery (SICS)

(scleral tunnel incision)(scleral tunnel incision)- Phacoemulsification (scleral Phacoemulsification (scleral

tunnel/clear corneal incision)tunnel/clear corneal incision)

Intra-ocular lens (IOL) typesIntra-ocular lens (IOL) types

Posterior chamber lens (PCL) Posterior chamber lens (PCL) Anterior chamber lens (ACL) Anterior chamber lens (ACL) - The best position for implantation of The best position for implantation of

IOL is within the capsular bag in the IOL is within the capsular bag in the posterior chamber. posterior chamber.

- The IOLs are made of PMMA The IOLs are made of PMMA (Polymethyl Methacrylate), Silicone (Polymethyl Methacrylate), Silicone or Acrylic (foldable).or Acrylic (foldable).

ICCEICCE

Principle: The lens is removed in toto as Principle: The lens is removed in toto as one single piece i.e., the nucleus and one single piece i.e., the nucleus and the cortex are removed the cortex are removed within the within the capsulecapsule of the lens after breaking the of the lens after breaking the zonules. zonules.

Indications:Indications:- Subluxated lensSubluxated lens- Dislocated lensDislocated lens

Disadvantages: Disadvantages: - There is no support left for posterior chamber IOL, There is no support left for posterior chamber IOL,

therefore, only anterior chamber IOL (ACL) can be therefore, only anterior chamber IOL (ACL) can be implanted which has risk of adverse corneal implanted which has risk of adverse corneal complications. complications.

- Also, there is no barrier left between anterior and Also, there is no barrier left between anterior and posterior segment, which increases the incidence posterior segment, which increases the incidence of other complications e.g., vitreous loss, aphakic of other complications e.g., vitreous loss, aphakic glaucoma, cystoid macular edema, glaucoma, cystoid macular edema, endophthalmitis, etc.endophthalmitis, etc.

Advantage: The only advantage is that after-Advantage: The only advantage is that after-cataract does not develop as the entire capsule is cataract does not develop as the entire capsule is removed.removed.

Methods:Methods:- Indian smith techniqueIndian smith technique- CryoextractionCryoextraction- Capsule forceps methodCapsule forceps method- Irisophake methodIrisophake method- Wire vectis methodWire vectis method

ECCEECCE Principle: The nucleus and the cortex is removed Principle: The nucleus and the cortex is removed out out

of the capsuleof the capsule leaving behind intact posterior capsule, leaving behind intact posterior capsule, peripheral part of the anterior capsule and the peripheral part of the anterior capsule and the zonules. zonules.

Advantages:Advantages:- Provides support of placement of PC IOLProvides support of placement of PC IOL- Prevents vitreous from bulging forwards and acts as a Prevents vitreous from bulging forwards and acts as a

barrier between anterior and posterior segment. This barrier between anterior and posterior segment. This results in decreasing the incidence of complications results in decreasing the incidence of complications viz. Vitreous loss, corneal edema, endophthalmitis, viz. Vitreous loss, corneal edema, endophthalmitis, cystoid macular edema, aphakic glaucoma, etc. cystoid macular edema, aphakic glaucoma, etc.

Disadvantages: Capsular remnants are prone to Disadvantages: Capsular remnants are prone to develop after-cataract develop after-cataract

Steps of conventional ECCESteps of conventional ECCE

SR bridle sutureSR bridle suture Conjunctival peritomyConjunctival peritomy Hemostasis- cauteryHemostasis- cautery Partial thickness limbal incision (10-2 Partial thickness limbal incision (10-2

o’clock)o’clock) Anterior chamber entryAnterior chamber entry Inject VESInject VES

Anterior capsulotomy:Anterior capsulotomy:- SmilingSmiling- CanopenerCanopener Extension of incisionExtension of incision HydrodissectionHydrodissection Removal of nucleus: pressure-Removal of nucleus: pressure-

counterpressure techniquecounterpressure technique

Cortex aspiration: simcoe I/A cannulaCortex aspiration: simcoe I/A cannula VES injected into capsular bagVES injected into capsular bag IOL implantationIOL implantation Aspiration of excess VESAspiration of excess VES Suture wound: 10-0 nylon Suture wound: 10-0 nylon Subconjunctival injection of Subconjunctival injection of

dexa+gentadexa+genta

SICSSICS

Sutureless cataract surgerySutureless cataract surgery Scleral tunnel incision (6 mm)Scleral tunnel incision (6 mm) CCCCCC Bring nucleus into ACBring nucleus into AC Delivery using wire vectis and dialler/ Delivery using wire vectis and dialler/

viscoexpressionviscoexpression Advantages:Advantages:- Tunnel is self-sealing, no suture requiredTunnel is self-sealing, no suture required- Less astigmatismLess astigmatism

Phacoemulsification Phacoemulsification

Scleral tunnel / clear corneal incisionScleral tunnel / clear corneal incision Small incision: 3-3.2 mmSmall incision: 3-3.2 mm CCCCCC HydrodelineationHydrodelineation Nucleus emulsification and aspiration Nucleus emulsification and aspiration

using phacoemulsification needle (1mm using phacoemulsification needle (1mm titanium needle vibrated at ultrasonic titanium needle vibrated at ultrasonic speed 40,000/sec)speed 40,000/sec)

Foldable lensFoldable lens

Advantages: Advantages: - Small incisionSmall incision- Less astigmatismLess astigmatism- Faster wound healingFaster wound healing Disadvantages:Disadvantages:- Risk of corneal endothelial damageRisk of corneal endothelial damage- Greater risk of nucleus dropGreater risk of nucleus drop- Expensive techniqueExpensive technique- Greater expertise required to master the Greater expertise required to master the

techniquetechnique

Postoperative managementPostoperative management

PainkillersPainkillers Bandage removal next morning- look Bandage removal next morning- look

for any postoperative complicationsfor any postoperative complications Antibiotic-steroid drops started- Antibiotic-steroid drops started-

continued for 1 month and then continued for 1 month and then taperedtapered

Final glass prescription: after 6-8 wksFinal glass prescription: after 6-8 wks