Pre and post operative management of cataract

knowledge purpose

1. Pre and post operative management of cataract Presenter: Kalpana B handari M.Optom (1 st sem ) TIO

2. Preoperative considerations Indications for surgery • Visual improvement: Operation is indicated when the opacity develops to a degree sufficient to cause difficulty in performing essential daily activities. • Medical indications are those in which a cataract is adversely affecting the health of the eye. Eg : - Lens induced glaucoma - Phacoanaphylactic endophthalmitis -Retinal diseases like diabetic retinopathy or retinal detachment. Cosmetic indication - to obtain black pupil.

3. Systemic preoperative assessment

4. P reoperative ocular assessment • Visual acuity assessment. Iop measurment - raised IOP needs priority management. • Cover test: A heterotropia may indicate amblyopia, which carries a guarded visual prognosis, or the possibility of diplopia if the vision is improved. A squint, usually a divergence , may develop in an eye with poor vision due to cataract , and lens surgery alone may straighten the eye .

5. • Pupillary responses. Because cataract never produces an afferent pupillary defect, its presence implies substantial additional pathology. • Ocular adnexa. Dacryocystitis , blepharitis , chronic conjunctivitis, lagophthalmos , ectropion , entropion and tear film abnormalities may predispose to endophthalmitis and in most cases optimization should be achieved prior to intraocular surgery.

6. Cornea: Eyes with decreased endothelial cell counts ( e.g.substantial cornea guttata ) have increased vulnerability to postoperative decompensation secondary to operative trauma. Anterior chamber: A shallow anterior chamber can render cataract surgery difficult. Recognition of a poorly dilating pupil allows intensive preoperative mydriatic drops, planned mechanical dilatation prior to capsulorhexis and/or intracameral injection of mydriatic. .

7. Lens : Nuclear cataracts tend to be harder and may require more power for phacoemulsification, while cortical and subcapsular opacities tend to be softer . Black nuclear opacities are extremely dense and extracapsular cataract extraction rather than phacoemulsification may be the superior option . Pseudoexfoliation indicates a likelihood of weak zonules ( phakodonesis – lens wobble – may be present ), a fragile capsule and poor mydriasis.

8. Fundus examination. Pathology such as age-related macular degeneration may affect the visual outcome. Ultrasonography may be required, principally to exclude retinal detachment and staphyloma , in eyes with very dense opacity that precludes fundus examination . Retinal function tests: i . Light Perception ii . Test for Marcus Gunn pupillary response iii . Projection of rays - Test for function of peripheral retina iv . Two light discrimination test - Macular function v . Maddox rod test vi . Colour perception-macular function and optic nerve vii . Entoptic visualisation -retinal function viii . Laser interferometry ix . Objective tests for evaluating retina- ultrasonic evaluation, ERG , EOG, VER and indirect ophthalmoscopy

9. Sclera. If a prominent explant/encircling band has been placed during prior retinal detachment surgery, the eye is particularly large or the sclera thin (e.g. high myopia), peri - and retrobulbar local anaesthesia may be avoided and special care taken with sub- Tenon local anaesthetic infiltration . Current refractive status: It is critical to obtain details of the patient’s preoperative refractive error in order to guide intraocular lens (IOL) implant selection. The keratometry readings (obtained during biometry) should be noted in relation to the refraction, particularly if it is planned to address astigmatism by means of targeted wound placement, a toric IOL or a specific adjunctive procedure .

10. Informed consent It is essential that the patient has arrived at a fully informed decision to proceed with cataract surgery. As well as discussing the benefits , risks should be conveyed at a level appropriate to each patient’s level of understanding, with an explanation of the more common and severe potential problems.

11. Biometry Biometry facilitates calculation of the lens power ; in its basic form this involves the measurement of two ocular parameters, keratometry and axial ( anteroposterior ) length. Keratometry involves determination of the curvature of the anterior corneal surface (steepest and flattest meridians), expressed in dioptres or in millimetres of radius of curvature. This is commonly carried out with the interferometry apparatus used to determine axial length but if this is unavailable or unsuitable manual keratometry (e.g. Javal – Schiøtz keratometer ) or corneal topography can be performed.

12. Optical coherence biometry is a noncontact method of axial length measurement that utilizes two coaxial partially coherent low-energy laser beams to produce an interference pattern (partial coherence interferometry ). Modern biometry devices also perform keratometry , anterior chamber depth and corneal white-to white measurement , and are able to calculate IOL power using a range of formulae. Measurements have high reproducibility and generally require less skill than ultrasonic biometry.

13. A-scan ultrasonography is a generally slightly less accurate method of determining the axial dimension and can be acquired either by direct contact or more accurately but with greater technical difficulty by using a water bath over the eye ( immersion ultrasonography ). The sound beam must be aligned with the visual axis for maximal precision; each reflecting surface is represented by a spike on an oscilloscope display monitor.

14. IOL power calculation formulae: Numerous formulae have been developed that utilize keratometry and axial length to calculate the IOL power required to achieve a given refractive outcome. Some formulae incorporate additional parameters such as anterior chamber depth and lens thickness to try to optimize accuracy. The SRK-T, Haigis , Hoffer Q and Holladay 1 and 2 are commonly used. Specific formulae may be superior for very short (possibly the Hoffer Q) or long eyes .

15. Previous refractive surgery : Any form of corneal refractive surgery is likely to make a significant difference to the IOL power required, and standard IOL calculations are unsuitable . Several different methods have been described to address this situation. Most involve the calculation of the post-refractive procedure ‘true’ corneal power using a special process (refractive history method, contact lens method) and insertion of this into a standard (e.g. Hoffer Q) or specific (e.g . Masket ) formula, but the Haigis -L regression formula uses statistical data to facilitate calculation on post-refractive surgery eyes using only standard inputs. It may prudent to utilize more than one method of IOL calculation.

16. Contact lenses. If the patient wears soft contact lenses, these should not be worn for up to a week prior to biometry to allow corneal stabilization; hard/gas permeable lenses may need to be left out for 3 weeks . • Personalized A-constant. If a consistent postoperative refractive deviation is found in most of an individual surgeon’s cases, it is assumed that some aspects of personal surgical (or possibly biometric) technique consistently and similarly influence outcome, and a personalized A-constant can be programmed into biometry apparatus to take this into account.

17. Corneal pachymetry Ultrasonic pachymeters can accurately & reliably measure endothelial cell function. If thickness > 600 µm maybe consistent with corneal edema & endothelium dysfunction that increase the likelihood postoperative clinical corneal edema. Specular microscopy : (endothelium cells) A normal cell count > 2400 cells/mm2 If a cell count fewer than 1000 cells/mm2 is risk of postoperative corneal decompensation .

18. Pre operative management in pediatric age groups Pediatric IOL : size, design and power. Size of IOL above the age of 2 years may be standard 12 to 12.75mm diameter for the bag implantation. Design of IOL recommended is one- piece PMMA with modified C- shaped haptics (preferably heparin coated) Power of IOL in children between 2-8 years of age 10% undercorrection from the calculated biometric power is recommended to counter the myopic shift. Below 2 years on undercorrection by 20% is recommended.  

19. Pre-op medications and preperations 1 . Topical antibiotics - Tobramycin and Gentamicin QID for 3 days before surgery. 2 . Preparation of the eye to be operated. 3. Consent. 4. Scrub bath and care of hair 5 . D rugs to lower IOP- acetazolamide 500mg stat 2 hours before surgery and glycerol 60ml mixed with equal amount of water or lemon juice 1 hour before Surgery or , IV mannitol 1gm/kg body weight half an hour before Surgery. 6. Drugs to sustain dilated pupil - antiprostaglandin eye drops(indomethacin).

20. Anaesthesia The majority of cataract surgery is performed under local anaesthesia (LA), sometimes in conjunction with intravenous or oral sedation. Types of local anaesthetics for cataract surgery are: a) Subtenon’s b) Peribulbar c)Topical General anaesthesia is required in some circumstances, such as children and many young adults, very anxious patients, some patients with learning difficulties, epilepsy, dementia and those with a head tremor.

21. Sub- Tenon block involves insertion of a blunt-tipped cannula through an incision in the conjunctiva and Tenon capsule 5 mm from the limbus inferonasally and passing it around the curve of the globe through the sub- Tenon space. The anaesthetic is injected beyond the equator of the globe. Although anaesthesia is good and complications minimal, akinesia is variable. Chemosis and subconjunctival haemorrhage are common but penetration of the globe is extremely rare.

22. • Peribulbar block is given through the skin or conjunctiva with a 1-inch (25-mm) needle. It generallyprovides effective anaesthesia and akinesia . Penetration of the globe is a rare but severe complication, and for this reason peribulbar is avoided, or approached with great caution , in longer eyes (which also tend to have a larger equatorial diameter).

23. • Topical anaesthesia involves drops or gel ( proxymetacaine 0.5%, tetracaine 1% drops, lidocaine 2% gel), which can be augmented with intracameral preservative-free lidocaine 0.2 %–1 %, combined viscoelastic/ lidocaine preparations are also commercially available . Although analgesia is generally adequate, it tends to be less effective than peribulbar or sub- Tenon blocks.

24. Post- operative management Patient is asked to lie quietly upon the back for 3/ 4 hours. For mild to moderate post-operative pain injection diclofenac sodium may be given. Next morning bandage is removed & inspected for post-op complication. Antibiotic-steroid eye drops are used two hourly 1 week , QID 4 week then tapering, TID, BD and OD for each week. Tear supplements are given for at least one month or more depending upon the patients complain to prevent post cataract surgery dry eyes.

25. Post -op examination Cornea: wounds sealed (Seidel test negative), clarity AC : formed, activity Pupil : round, regular and reacting PCIOL : centred and in the bag Consider : IOP checking Give clear instructions re postoperative drops Use of clear shield What to expect (discomfort, watering) What to worry about (increasing pain/ redness, worsening vision) Where to get help (including telephone number)

26. Final review (2-4wks later ) Examination VA : unaided/aided Cornea : wounds sealed (Seidel test negative), clarity AC : depth and clarity Pupil : round, regular and reacting IOP Fundus : no cystoid macular oedema , flat retina If good result then either list for second eye (in bilateral cases) or discharge for refraction as appropriate.

27. If disappointing VA (unaided) perform refraction to look for ‘refractive error’ and dilated fundoscopy to check for the subtle CMO (specially if VA (pinhole) < VA (unaided)) and if in doubt, consider OCT .

28. Refractive surprises In patients where the refractive outcome is harder to predict (high ametropia , previous corneal refractive surgery), review patients early (1 week) with refraction to permit the option of an early IOL exchange if a large discrepancy noticed. After 6-8 weeks of operation corneoscleral sutures are removed (when applied ). Final spectacles are prescribed after about 8 weeks of operation.  

29. Management of refractive error in adults Refractive error is assessed at 8th week of cataract surgery. Refractive correction is prescribed only if the error persist even after three months of cataract surgery.

30. Postoperative refraction Emmetropia is typically the desired postoperative refraction, though usually spectacles will be needed for near vision since a conventional IOL cannot accommodate . Many surgeons aim for a small degree of myopia (about -0.25 D) to offset possible errors in biometry; postoperative hypermetropia , which necessitates correction for clear vision at all distances, is typically less well tolerated than myopia.

31. Postoperative refraction Contralateral eye. Postoperative refractive planning must take account of the contralateral eye. If this has a significant refractive error but is unlikely to require cataract surgery within a few years, the postoperative target for the operated eye might be set for within less than 2.0 D of its fellow, to avoid problems with binocular fusion. In some cases, such as when there is an early lens opacity in the fellow eye or when ametropia is extreme, the patient can be offered lens surgery to the other eye to facilitate targeting both at emmetropia .

32. ‘ Monovision ’ is a concept in which the (usually) nondominant eye is left with between 1 and 2 dioptres of myopia to allow reading, whilst emmetropia is targeted in the dominant eye. This is attractive to some patients, generally those who have previously been using contact lenses or spectacles to achieve monovision . • Multifocal lens options use a variety of optical means to attempt to achieve satisfactory near, distance and intermediate vision. Many patients are very satisfied with the results but a significant minority are unhappy, complaining of phenomena such as glare.

33. In evaluating reduced post-operative acuity, one should know both the timing and severity of the visual complaint in order to determine an etiology. 1) Early Visual Impairment Severe (20/200 or worse) Moderate (20/100 or better) 2) Delayed Visual Recovery

34. Early visual impairement Epithelial Irregularity Irregular or Marked Corneal Astigmatism Corneal Edema Dislocated / subluxated IOL Operative / Post-operative bleeding Retained Cortex or Nuclear fragments Hypotony Photoretinal Toxicity Extraocular Muscle paresis These complications predominantly affect optical clarity, macular function or refractive state.

35. Early visual impairement Vascular Occlusion Retinal Detachment Infectious Endophthalmitis Toxic Anterior Segment Syndrome Delayed Suprachoroidal Hemorrhage Optic Nerve Damage Globe Rupture or Perforation Intraocular aminoglycoside toxicity These injuries often occur through vascular insult, direct mechanical injury, or retinal toxicity.

36. Operative complications Rupture of the posterior lens capsule: Capsular rupture may be accompanied by vitreous loss, posterior migration of lens material and, rarely, expulsive haemorrhage . Sequelae to vitreous loss, particularly if inappropriately managed, include CMO, retinal detachment, endophthalmitis , updrawn pupil , uveitis, vitreous touch, vitreous wick syndrome, glaucoma and posterior dislocation of the IOL . Posterior loss of lens fragments: Dislocation of fragments of lens material into the vitreous cavity after zonular dehiscence or posterior capsule rupture is rare but potentially serious as it may result in glaucoma, chronic uveitis , retinal detachment or chronic CMO .

37. Posterior dislocation of IOL Dislocation of an IOL into the vitreous cavity is rare; loss can occur via a posterior capsular dehiscence, or in an eye with fragile zonular attachments (e.g. pseudoexfoliation ) the entire capsular bag may dislocate. Complications include vitreous haemorrhage , retinal detachment, uveitis and chronic CMO. Treatment involves pars plana vitrectomy with IOL removal , repositioning or exchange depending on the extent of capsular support.

38. Suprachoroidal haemorrhage A suprachoroidal haemorrhage involves a bleed into the suprachoroidal space from a ruptured posterior ciliary artery. If sufficiently severe it may result in extrusion of intraocular contents (expulsive haemorrhage ). Contributing factors include advanced age, glaucoma, increased axial length, systemic cardiovascular disease, vitreous loss and conversion from phacoemulsification to ECCE.

39. Suprachoroidal haemorrhage contd … Immediate treatment involves filling of the AC with a cohesive viscoelastic and sutured closure of the incision. Tamponade the bleeding vessel; balloon (e.g. Honan) compression to a pressure of 50 mmHg, for up to 30 minutes. It may be helpful to keep the patient in a sitting rather than lying position. Postoperatively, topical and systemic steroids should be used aggressively to reduce intraocular inflammation, with standard postoperative antibiotic treatment and IOP management as indicated. Subsequent treatment , if spontaneous absorption fails to occur, consists of drainage of large haemorrhages . This can be performed 7–14 days later . Pars plana vitrectomy may be considered when the retina appears adherent or detached,

40. Vascular occlusion CRVO ,CRAO , Choroidal Infarction may occur in s urgery if complicated by : retrobulbar hemorrhage nerve sheath injection elevated IOP

41. Acute postoperative endophthalmitis Pathogenesis: Acute intraocular infection is invariably a severe event . Toxins produced by infecting bacteria and the host inflammatory responses cause rapid and irreversible photoreceptor damage. Risk factors: O perative complications such as posterior capsule rupture, prolonged procedure time, combined procedure (e.g. with vitrectomy ), clear corneal sutureless incision, temporal incision, wound leak on the first day, delaying postoperative topical antibiotics until the day after surgery, topical anaesthesia , adnexal disease and diabetes.

42. Acute postoperative endophthalmitis Pathogens. About 90% of isolates are Gram-positive and 10% Gram-negative. Staphylococcus epidermidis is the most common, and with early treatment carries a reasonable prognosis . The source of infection: Flora of the eyelids and conjunctiva are the most frequent source, includingcontamination via incisions in the early postoperative stages . Other potential sources include contaminated solutions and instruments, environmental air, and the surgeon and other operating room personnel.

43. Acute postoperative endophthalmitis Prophylaxis: Instillation of 5% povidone -iodine into the conjunctival fornices and leaving this undisturbed for at least 3 minutes prior to surgery . Scrupulous preparation of the surgical site, with re-draping if eyelash coverage is inadequate. Treatment of pre-existing infections such as blepharitis , conjunctivitis , chronic dacryocystitis and infection in the contralateral eye or socket . Antibiotic prophylaxis: Intracameral cefuroxime (1 mg in 0.1 ml) injected into the AC at the end of surgery . Postoperative subconjunctival injection can achieve bactericidal levels in the AC for at least 1–2 hours . Preoperative topical fluoroquinolone antibiotics are frequently given in regimens from 1 hour to 3 days before surgery.

44. Clinical features: • Symptoms. Pain, redness and visual loss. • Signs vary according to severity. ○ Eyelid swelling, chemosis , conjunctival injection and discharge. ○ A relative afferent pupillary defect is common. ○ Corneal haze. ○ Fibrinous exudate and hypopyon . ○ Vitritis with an impaired view of the fundus. ○ Severe vitreous inflammation and debris with loss of the red reflex.

45. Acute postoperative endophthalmitis Differential diagnosis: • Retained lens material in the AC or vitreous may precipitate a severe uveitis, corneal oedema and raised IOP . • Vitreous haemorrhage . • Postoperative uveitis. If signs of inflammation are mild a trial of topical steroid therapy and early review ( 6–24 hours ) is appropriate . If there is no substantial improvement , management should be that of endophthalmitis . • Toxic reaction . • Complicated or prolonged surgery may result in corneal oedema and uveitis.

46. Treatment : Intravitreal antibiotics: Antibiotics commonly used in combination are ceftazidime , which will kill most Gram-negative organisms (including Pseudomonas aeruginosa ) and vancomycin to address Gram-positive cocci (including methicillin-resistant Staphylococcus aureus ). First choice: Vancomycin 1 mg in 0.1 ml + ceftazidime 2.25 mg in 0.1 ml . Second choice: Vancomycin 1 mg in 0.1 ml + Amikacin 0.4 mg in 0.1 ml . Third choice: Vancomycin 1 mg in 0.1 ml + gentamycin 0.2 mg in 0.1 ml. Note: Gentamycin is 4 times more retinotoxic ( causes macular infarction) than amikacin . Preferably the aminoglycosides should be avoided.

47. Subconjunctival injections of antibiotics should be given daily for 5-7 days to maintain therapeutic intraocular concentration : First choice : Vancomycin 25 mg in 0.5 ml plus Ceftazidime 100 mg in 0.5 ml. Second choice : Vancomycin 25 mg in 0.5 ml plus Cefuroxime 125 mg in 0.5 ml Topical concentrated antibiotics should be started immediately and used frequently (every 30 minute to 1 hourly). To begin with a combination of two drugs should be preferred. Vancomycin (50 mg/ml) or cefazoline (50mg/ml ) + Amikacin (20 mg/ml) or tobramycin (15 mg%).

48. Oral antibiotics. Fluoroquinolones penetrate the eye well and moxifloxacin 400 mg daily for 10 days is recommended; clarithromycin 500 mg twice daily may be helpful for culture-negative infections . Steroid therapy : Topical dexamethasone (0.1%) or predacetate (1 %) used frequently . Subconjunctival injection of dexamethasone 4mg (1ml) OD for 5-7 days . Intravitreal injection of dexamethasone 0.4 mg (0.1ml). Systemic steroids: Oral corticosteroids should preferably be started after 24 hours of intensive antibiotic therapy. A daily therapy regime with 60 mg prednisolone to be followed by 50, 40, 30, 20 and 10 mg for 2 days each may be adopted.

49. Supportive therapy 1. Cycloplegics. Preferably 1% atropine or alternatively 2% homatropine eyedrops should be instilled TDS or QID. 2. Antiglaucoma drugs.In patients with raised intraocular pressure drugs such a oral acetazolamide (250 mg TDS) and timolol ( 0.5%BD ) may be prescribed . Vitrectomy operation should be performed if the patient does not improve with the above intensive therapy for 48 to 72 hours or when the patient presents with severe infection with visual acuity reduced to light perception. Vitrectomy helps in removal of infecting organisms, toxins and enzymes present in the infected vitreous mass.

50. Delayed-onset postoperative endophthalmitis Pathogenesis: 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 ). Organisms can become sequestered within macrophages , protected from eradication but with continued expression of bacterial antigen . Onset ranges from 4 weeks to years (mean 9 months) postoperatively and typically follows uneventful cataract surgery . It may rarely be precipitated by laser capsulotomy release of the organism .

51. Delayed-onset postoperative endophthalmitis Diagnosis • Symptoms. Painless mild progressive visual deterioration is typical; floaters may be present . • Signs ○ Low-grade anterior uveitis, sometimes with medium large keratic precipitates; a degree of vitritis is common. ○ The inflammation initially responds well to topical steroids , but recurs when treatment is stopped and may eventually become steroid-resistant. ○ An enlarging capsular plaque composed of organisms sequestrated in residual cortex within the peripheral capsular bag is common; gonioscopy under mydriasis may identify an equatorial plaque.

52. Delayed-onset postoperative endophthalmitis Initial management. Later-generation fluoroquinolones , such as moxifloxacin , penetrate the eye well, and are concentrated within macrophages. An empirical 10–14-day course of moxifloxacin (alternatives include clarithromycin) may be worthwhile prior to more invasive options . • Investigation. Sampling of aqueous and vitreous should be considered if oral antibiotics are ineffective. Anaerobic culture should be requested if P. acnes infection is suspected, and isolates may take 10–14 days to grow. The detection rate can be greatly improved with the use of PCR, which should also screen for the common causes of viral anterior uveitis.

53. Treatment if persistent ○ Intravitreal antibiotics alone are usually unsuccessful in resolving the infection. ○ Removal of the capsular bag, residual cortex and IOL, requiring pars plana vitrectomy . Secondary IOL implantation may be considered at a later date . Intravitreal antibiotics are combined: vancomycin (1–2 mg in 0.1 ml) is the antibiotic of choice and can also be irrigated into any capsular remnant. P . acnes is also sensitive to methicillin, cefazolin and clindamycin.

54. Toxic Anterior Segment Syndrome(TASS) Develop in response to retained lens, toxic intraocular reaction, mechanical irritation, exacerbation of pre-existing uveitis. Most common clinical symptom is significantly blurred vision. Corneal Edema is most common clinical finding: - Limbus to limbus -Indicative of widespread endothelial damage

55. Marked anterior segment inflammation Hypopyon Fibrin from surface of iris onto surface to IOL, to wound and side ports . Can create significant iris damage -Permanently dilate - Transillumination -Damage to TM leading to secondary glaucoma Treatment: Immediate high dose topical corticosteroid. IOP monitoring Usually low at start but can rise rapidly. Specular Microscopy to Monitor for permanent endothelial damage.

56. Delayed visual impairement By 6 weeks, intraocular inflammation and minor corneal edema should be resolved, IOP should be normal, and the macula should be distinct without edema . Delayed visual impairement occurs due to; Epithelial Irregularity Persistent Corneal Edema Irregular or high corneal astigmatism IOL subluxation, tilt, or capture Anterior Segment Inflammation Posterior Segment Inflammation Hypotony Posterior Vitreous Detachment Macular Edema Photoretinal Toxicity Under Diagnosed pre-existing conditions Incorrect IOL power Posterior capsular opacification (PCO)

57. Photoretinal toxicity Photoretinal injury from operating microscope. Patients complain of scotoma . If injury near fovea, VA will be compromised. Appears as subtle pale oval lesion, commonly located inferior to fovea. Healing results in mottling of RPE – Prognosis is excellent if outside fovea.

58. Rebound Inflammation Occurs in 5% of patients. More common in dark iridies . More common in patients with DM. Occurs when steroids are discontinued to early or tapered too quickly. Always look for retained lens material with gonioscopy. Treatment: Resume topical steroids. Consider cycloplegia. Consider tap and injection to rule out chronic endophthalmititis .

59. Posterior capsular opacification Visually significant posterior lens capsular opacification (PCO ), also known as ‘after cataract’, is the most common late complication of uncomplicated cataract surgery, historically occurring eventually in up to 50% of patients . It is caused by the proliferation of lens epithelial cells that have remained within the capsular bag following cataract extraction. The incidence of PCO is reduced when the capsulorhexis opening is in complete contact with the anterior surface of the IOL.

60. Treatment Treatment involves the creation of an opening in the posteriorcapsule , termed a capsulotomy , with the Nd:YAG laser . Indications : The presence of significant visual symptoms is the main indication; less commonly, capsulotomy is performed to improve an inadequate fundus view impairing assessment and treatment of posterior segment pathology. Complications I nclude pitting of the IOL , intraocular pressure elevation (usually mild and transient) and extremely rarely CMO, retinal detachment and IOL subluxation or dislocation.

61. Anterior capsular fibrosis and contraction Since the advent of continuous curvilinear capsulorhexis , contraction of the anterior capsular opening ( capsulophimosis ) has become a more common complication . It typically progresses over months, and if severe, YAG laser anterior capsulotomy may be required. Risk factors include pseudoexfoliation , retinitis pigmentosa and a small capsulorhexis .

62. Cystoid macular oedema Symptomatic CMO is relatively uncommon following uncomplicated phacoemulsification and in most cases is mild and transient . It occurs more often after complicated surgery and has a peak incidence at 6–10 weeks, although the interval to onset may be much longer . Risk factors: I nclude epiretinal membrane, a history of CMO in the other eye, operative complications such as posterior capsular rupture, particularly with vitreous incarceration into the incision site, anterior chamber IOL, secondary IOL implantation, prior topical prostaglandin treatment, diabetes and uveitis.

63. Cystoid macular oedema contd … Treatment : One or a combination of the following modalities may be used : Anterior vitrectomy or YAG laser vitrotomy to vitreous incarceration in the anterior segment if present . Topical NSAIDs (e.g. ketorolac four times daily, bromfenac twice daily, nepafenac ) may be beneficial even in long-standing cases; treatment for several months may be necessary . Steroids . Topically, by periocular or intravitreal (triamcinolone acetate 0.05–0.1 ml of 40 mg/ml) injection . Carbonic anhydrase inhibitors given systemically or topically. Intravitreal anti-VEGF agents . Pars plana vitrectomy may be useful for CMO refractory to medical therapy, even in eyes without apparent vitreous disturbance.

64. Dysphotopsia Up to 1 in 10 patients complain of annoying visual phenomena following uncomplicated cataract surgery. Symptoms. A dark shadow in the temporal periphery (negative dysphotopsia – often the most troublesome), scintillations, haloes, peripheral or central flaring or flashes (positive dysphotopsia ) and possibly monocular diplopia. Treatment: Encouraging the patient that the symptoms usually improve over time, both because of anatomical changes (e.g. capsulorhexis edge thickening) and because the brain is able to ignore unwanted images. IOL exchange (round-edged) may be considered.

65. Corneal decompensation Corneal oedema is very common postoperatively but is usually mild and transient. Eyes with pre-existing corneal endothelial pathology, particularly low cell counts, are at increased risk . Causes of more marked oedema include dense nuclei requiring high phacoemulsification energy, complicated or prolonged surgery , pseudoexfoliation , intraoperative endothelial trauma and elevated postoperative IOP. Use of a dispersive viscoelastic, and possibly a scleral tunnel incision, may help to protect the corneal endothelium during surgery in higher-risk eyes.

66. Ptosis Mild ptosis, probably secondary to a variety of mechanisms, is common after cataract surgery, but usually improves; observation for at least a year postoperatively is recommended in most cases .

67. Malposition of the IOL Although uncommon, malposition may be associated with both optical and structural problems. Significant malposition may require repositioning or replacement, occasionally with an iris or sclerally fixated lens.

68. Retinal detachment Rhegmatogenous retinal detachment (RRD) is uncommon . Preoperative risk factors include lattice degeneration and retinal breaks – both are generally treated prophylactically prior to cataract surgery (and probably laser capsulotomy )- and high myopia. The key intraoperative risk is vitreous loss. Pars planavitrectomy is usually the surgical modality employed for pseudophakic RRD.

69. Thank you