posterior capsular rent and nucleus drop

Posterior Capsular Rent (PCR), is a breach in the posterior capsule of the crystalline lens during cataract surgery. A common yet feared complication of cataract surgery, posterior capsular rent may lead to sub-optimal visual outcomes If not recognized early or managed appropriately. The consequences of this complication vary with the stage at which it occurred or was recognized, the coexisting pathologies in the operated eye, expertise of the operating surgeon and the facilities available to manage it. Consequent vitreous loss is also a major determinant of post-operative outcomes.

1. POSTERIOR CAPSULAR RENT & NUCLEUS DROP Dr krithika .v 1st year PG

2. INTRODUCTION : Posterior Capsular Rent (PCR), is a breach in the posterior capsule of the crystalline lens during cataract surgery.

3. Risk factors Patient related Surgeon related Machine related

4. PATIENT RELATED General Factors Anxiety, O ld age, COPD (chronic obstructive pulmonary disease), Demented patients or patients with inadvertent head movements . Age: Rise in PCR rates with increasing patient’s age.

5. EXTRAOCULAR FACTORS Deep set eyes with a prominent brow: Surgical maneuvering will be difficult. A temporal approach may be preferred. Deep set eyes may also allow pooling of irrigating solution over the ocular surface causing reflections and reducing the visibility during surgery. Exaggerated Bell’s phenomenon : Due to this the eye moves upwards and keeping the eye in the field of operating microscope may be difficult.

6. INTRAOCULAR FACTORS Conditions with visibility issues: Grade 3 Pterygium, Fuchs endothelial dystrophy, Corneal scarring, Extensive arcus senilis, Spheroidal degeneration, Band keratopathy etc.

7. Type of cataract: Certain types of cataracts increase the potential for posterior capsular rupture. These are: Intumescent Cataract Brunescent/Black Cataract Posterior Polar Cataract Cataract associated with posterior lenticonus or lentiglobus Traumatic Cataract

8. Pseudoexfoliation: Associated with weak zonules, non-dilating pupils and hard cataract increasing incidence of posterior capsular rupture and zonular dehiscence.

9. Small Pupils: Reduces the working space and hinders visibility. Intraoperative Floppy Iris Syndrome (IFIS): history of alpha-1 blocker use Posterior Synechiae Long-term use of topical Pilocarpine Pseudoexfoliation Diabetes Mellitus Senility Congenital: Coloboma of iris, iridoschisis

10. Shallow Anterior Chamber: In hypermetropes, the phaco needle is closer to the posterior capsule with a greater risk of PC rent I ris prolapse is also common since infusion from phaco tip may flow behind the iris root , which will balloon it & force it out of the incision

11. D EEP ANTERIOR CHAMBER : 1. High myopia: A trampolining posterior capsule due to thinner and more elastic tissues, Lack of scleral rigidity and Zonular laxity. 2. Post pars plana vitrectomy eyes: Lack of vitreous support.

12. 3. Lens Iris Diaphragm retropulsion syndrome (LIDRS): The mechanism is reverse pupillary block with excessive anterior chamber deepening. If a pronounced post-occlusion surge occurs, a sudden shallowing of AC may follow and PC Rent may occur. This rapid fluctuation in AC depth may be controlled by keeping BSS (Balanced Salt Solution) bottle at a lower height , vacuum and flow rate settings lower than usual. Alternatively, a second instrument such as an iris hook can be used to manually lift the iris from the surface of the lens to distribute pressure.

13. MACHINE RELATED Unfamiliar devices Sudden intraoperative machine dysfunction Faulty settings of operating microscope (Inadequate brightness, improper magnification , incorrect IPD etc…) Interruption of infusion flow causing sudden AC collapse (bottle finishing midway, loose irrigation line, or kinks in tubing) SURGEON RELATED Inexperienced Surgeons

14. Types of Capsular Tears According to Location IA Perpendicular Pre-equatorial IB Acute-Angled Pre-equatorial IIA Perpendicular Post-Equatorial IIB Acute-Angled Post-Equatorial III Pre-equatorial with Argentinian flag sign IV Post-equatorial with Argentinian flag sign V Mini Punch

15. PREVENTION Pre-operative Evaluation: History: Previous ocular trauma Surgical procedures Ocular and systemic, recent or chronic use of medications Examination: A thorough slit lamp exam to analyze ocular adnexa and surfaces, corneal transparency, AC depth, anterior and posterior capsule integrity, zonular status and grade of cataract. The fellow eye should also be examined (especially looking for complicated cataract surgery). Intraocular pressure Dilated fundoscopy for evaluation of posterior segment Specular microscopy for corneal endothelial health (If history of previous surgery, hard cataract, trauma or a very elderly patient)

16. Anaesthesia : Peribulbar anesthesia instead of topical is preferable in anxious patients. General anesthesia is preferred for children, patients with neurologic disorders or mentally unstable patients. Sedation may help excessively anxious patients. In phacomorphic glaucoma, intravenous mannitol should be administered to reduce IOP (intraocular pressure) and vitreous upthrust.

17. IDENTIFYING HIGH RISK CASES Systemic: Musculoskeletal problems hampering prolonged supine positioning of the patient Neurological disorders affecting patient cooperation Cardiopulmonary conditions causing anxiety and breathing problems during surgery A short neck or obesity can increase vitreous pressure leading to instability of the anterior chamber Use of medications such as alpha blockers responsible for Intra-operative Floppy Iris Syndrome.

18. Ocular: Smaller palpebral fissures or deep-set eyes causing difficulties in placing speculum. Pooling of fluid which commonly occurs in deep sockets, causes reflections which compromise visibility and limit surgeon’s maneuverability Excessively shallow or Deep AC Non-dilating pupil or synechiae Fibrotic or breached capsule. Capsules in children are more elastic posing a challenge during capsulorhexis. Subluxated lens, zonular dehiscence or weakening e.g., pseudoexfoliation. Ocular comorbidities like silicone oil-filled vitrectomized eyes, glaucoma, previous trauma or uveitis.

19. Surgical Strategies to Minimize Risk of a Posterior Capsule Rent Draping and Speculum The drape should not allow exposure of lashes and should not obscure the surgical field. The speculum should be of appropriate size and should ideally be lightweight as to avoid undue pressure on the globe leading to increased posterior segment pressure against the lens.

20. Wound construction T riplanar incisions are ideal since they resist leakage and are self-sealing. Too small an incision can cause wound burn and localized corneal edema. Inappropriately wide incisions lead to chamber instability Such an incision can be sutured and another site chosen to reconstruct a proper incision.

21. Maintenance of Intraoperative visibility Use of a microscope with good stereoscopic depth perception and coaxial illumination is recommended. Pooling of fluid should be prevented by ensuring proper head positioning allowing for escape of fluid. Two percent Hydroxypropyl Methylcellulose is found to be superior to Balanced Salt Solution (BSS) to prevent corneal drying and haze.

22. Non-Dilating pupils Intracameral adrenaline, Malyugin ring, B-Hex ring, other pupil expansion devices or iris hooks can greatly help enlarge pupils intraoperatively. Posterior synechiae can be released by instilling Ophthalmic Viscosurgical Device (OVD) and using Sinskey hooks to break adhesions. A well-dilated pupil prevents PCR by allowing a wider view of the rhexis margins and the posterior capsule.

23. Handling Anterior Capsule An intact Continuous Curvilinear Capsulorhexis (CCC) is fundamental in preventing a capsular breach. To minimize complications, beginners should aim for a larger capsulorhexis (5-5.5mm) and use Trypan Blue to stain the anterior capsule despite a good fundal glow. Vannas scissors may be required to cut the fibrotic areas in the anterior capsule during capsulorhexis to prevent lateral extension.

24. For capsulorhexis in intumescent cataracts with high intra-lenticular pressure, techniques such as two-stage capsulorhexis, excessive use of viscocohesive OVDs, trypan blue dye and chandelier endoillumination systems have been described. Femtosecond-laser assisted capsulotomy is considered safer and more convenient in intumescent cataract cases. Zonular insertions on the anterior capsule may sometimes be long enough to be traversed by the leading capsulorhexis margin resulting in zonular disinsertion. Presence of anterior zonules can easily be determined on a pre-operative slit-lamp exam with a well-dilated pupil.

25. Hydrodissection This step should be instituted with great caution. Before commencing, the anterior chamber should be decompressed by allowing outflow of some of the OVD through the incision. To prevent a sudden increase in intralenticular pressure, small amounts of fluid should be introduced beneath the anterior capsule and the nucleus gently tapped to release trapped fluid. Aggressive hydrodissection in the presence of a small capsulorhexis can lead to Capsular Block Syndrome and consequently a PCR. Cortical cleaving hydrodissection reduces the need for cortical removal thereby preventing capsule rupture.

26. Hydrodelineation This step separates the nucleus from the epinucleus, which acts like a protective shell during trenching, cracking and emulsification, and prevents inadvertent direct entry of the posterior capsule into the probe tip. A thorough hydrodelineation with multiple rings enhances safety by providing cushioning especially in posterior polar cataracts. Grooving A Posterior breach is more likely to occur in very soft or very hard cataracts. Beginners with less foot pedal control, use of a burst phaco mode and a very deep linear trench are risk factors for a PCR. A change in red reflex seen in the floor of the trench is a good sign of adequate groove depth.

27. Irrigation and Aspiration I/A probe tip should not be directed towards the posterior capsule to prevent its rupture. Sleeve-tip distance should be adjusted and special care should be taken to not let the anterior chamber collapse in eyes with fragile posterior capsules e.g, posterior polar cataracts. Cases with inadequate hydrodissection may require extensive I/A further increasing the risk. Accidental aspiration of PC into the I/A tip may result in visible converging folds (Spider Sign). On identification, they should be released immediately using the reflux function of the foot pedal.

28. IOL Insertion Before inserting the IOL, the capsular bag should be filled with OVD to push the posterior capsule away followed by a slow and controlled injection. Automated injectors are preferable to manual ones which should be thoroughly examined for smoothness before loading and injecting the IOL. For sulcus placement, cohesive OVDs should be injected behind the iris to make space

29. Lower fluidics and Slow Phacoemulsification Low aspiration flow rate, phaco power and vacuum settings and infusion pressure allow for reduced pressure differences during various steps of surgery, decreasing risk of complications like PC rents, iris tears and vitreous prolapse. This may be especially useful for inexperienced surgeons. Decreasing parameters while emulsifying the last nuclear piece in a hard cataract, in posterior polar cataracts, zonular laxity and IFIS all reduce the risk of complications.

30. MANAGEMENT Early Recognition Sudden deepening of Anterior chamber with momentary pupil dilatation Sudden transitory appearance of Red Reflex peripherally Tremulousness of the nucleus Difficulty in rotating a previously mobile nucleus due to vitreous within capsular bag Movements of pupillary margin inconsistent with AC manipulation by instruments Excess tipping of one pole of the nucleus P artial descent of the nucleus into anterior vitreous space

31. PRINCIPLES OF MANAGEMENT Stabilize the Anterior Chamber Whenever a PCR is suspected, it is imperative to not withdraw the instruments from the AC. This can lead to a collapsed AC with possible extension of the tear, vitreous prolapse and displacement of lens fragments into the posterior segment. If there is no imminent danger of the nucleus fragments falling into the posterior chamber, the second instrument should be carefully withdrawn and viscoelastic injected through the side port incision.

32. SWITCH TO LOW FLUIDICS : Flow Rate: Lower flow rate feeds less fluid and fragments into the probe, increases surgeon’s control over the case and narrows intraocular pressure variations. The risk of nuclear fragments falling posteriorly due to fluid flow also decreases. Irrigation Pressure: High pressures can also push lens fragments posteriorly. Bottle height should be lowered to reduce turbulence within the AC. Vacuum: High vacuum can lead to higher post occlusion surge attracting a sudden large volume of fluid from the AC into the tubing, causing the AC to collapse and again lead to lens drop. Irrigation & aspiration should also be done on significantly low settings.

33. A large amount of dispersive viscoelastic can be injected through the posterior capsule to create an effective barrier between the vitreous and contents of the AC. This allows for safer phacoemulsification of the remaining lens fragments in the AC. Vitreous Detection Before Irrigation & aspiration Presence of vitreous can be ascertained by injecting triamcinolone (approx. 10 times diluted) into the AC. It vitreous is detected, careful anterior vitrectomy should be done. Before Irrigation and Aspiration it is crucial to ascertain the absence of vitreous in the AC, since undue forces on vitreous strands can lead to retinal traction and detachment.

34. If tear identified during phacoemulsification  Residual nuclear material removed by 1.continuing phacoemulsification or 2. converting to larger incision, manual ECCE If most of the nucleus already emulsified and no vitreous in AC  Use second instrument to remove remaining nucleus away from the tear. Second instrument may be placed behind the nuclear fragment to prevent its descent through small rent

35. Start removing cortex in quadrants that are away from tear Cortex should be stripped towards the rent because any force directed away from it will cause its extension Some cortex can be left behind if there is risk of extension of tear Bimanual I/A permits the flow to be directed away from the capsular defect Alternate method of cortex removal is manual aspiration alternating between a bent cannula and J shaped cannula while maintaining AC depth with repeated OVD injections DRY manual aspiration of cortex reduces risk of extension of tear and precipitating vitreous prolapse Bimanual irrigation  and aspiration through two limbal paracentesis incisions to remove epinuclear fragments still supported by the Viscoat trap.

36. FOUR SPECIAL MANEUVERS: Advanced techniques in PCR with residual lens material MODIFIED PAL TECHNIQUE ( posterior assisted levitation ) If nucleus has partially descended through a capsular defect onto anterior hyaloid face | Pars Plana Sclerotomy made 3.5mm behind limbus | Dispersive OVD is injected to elevate the nuclear fragments & separate from underlying vitreous and a spatula is used to maneuver behind the nucleus before bringing it forward  Posterior assisted levitation of fragments with Visco injection through cannula tip inserted via pars plana sclerotomy. Phaco tip with Sheets glide can be used to remove fragments.

37. ADVANTAGE : It protects against inducing vitreous traction when elevating the nuclear piece (If nuclear pieces are no longer visible or accessible from an anterior approach, refer to vitreo retinal surgeon for retrieval )

38. 2. VISCOELASTIC TRAP TECHNIQUE : It prevents posterior descent of the residual nucleus and cortex Done if vitrectomy must be performed with lens material still in AC Any free floating lens material is elevated towards the cornea with dispersive OVD which is then used to fill AC | Bimanual anterior vitrectomy done using pars plana sclerotomy | By keeping vitreous cutter tip behind pupillary plane, any prolapsing vitreous bands will be transected without aspirating the OVD that has filled AC ADVANTAGE – The residual lens material remains supported by the OVD layer than by vitreous Despite vitreous prolapse, epinucleus and cortex are trapped anteriorly by filling the anterior chamber with a cushion of dispersive viscoelastic.

39. 3. SCAFFOLD TECHNIQUE : 3- piece IOL is placed in sulcus which acts as 2 way barrier to prevent nuclear fragments from descending posteriorly after PC tear | Now emulsification of nuclear fragments anterior to the optic done which blocks vitreous from being aspirated by the phaco tip DISADVANTAGE – contraindicated if any vitreous is in AC ALTERNATE TECHNIQUE by mark Michelson : Inserting trimmed sheets glide beneath the nucleus and in front of PC rent thereby creates an artificial posterior capsule provides same 2 way barrier as the IOL scaffold

40. 4. HOWARD GIMBEL TECHNIQUE : Here conversion of a small ,central linear tear into posterior capsulorrhexis Anterior hyaloid face is retroplaced with OVD | Fine capsulotomy forceps used to grasp and redirect edge of the tear until continuous edge is achieved | Now the capsular defect will not expand during IOL implantation and position

41. IOL PLACEMENT IN PC TEAR Based on amount and location on residual capsule, surgeon must decide on IOL design In Posterior capsular tear converted to posterior capsulorrhexis - Any PCIOL can be Kept in capsular bag In small PC rent without posterior capsulorrhexis – keeping any IOL in capsular bag may extend the tear If PC tears during IOL implantation , it may be possible to prolapse and capture the optic through the capsulorrexis (REVERSE OPTIC CAPTURE) Single piece acrylic IOL’s – unsuitable for ciliary sulcus fixationdue to thicker haptics , unfinished sharper edges , shorter length If anterior capsulorrhexis intact – 3 piece IOL with C-loop haptics placed in ciliary sulcus and the optic is button holled through rrhexis ( length of foldable 3 piece IOL -13mm , so they may not fully bridge the PC )

42. OSHER BOUNCE TEST - to confirm adequate fixation by slightly decentering the lens toward each haptic and releasing it to observe for spontaneous recentering If the IOL doesn’t recenter itself , haptic should be rotated to different meridian Persistent decentration needs suture fixation to the iris or sclera In absence of capsular support, either implant an angle supported ACIOL suture fixate PCIOL to iris or sclera or use intrascleral haptic fixation of 3piece IOL If ACIOL is used , each haptic should be flexed,lifted and reseat itself in the angle to prevent iris entrapment

43. Post-Operative Management Good patient communication and managing expectations Including topical Non-Steroidal Anti-Inflammatory (NSAID) drugs to the standard post-op regimen reduces risk of CME. Addition of a topical IOP lowering agent can also be considered. Regular post op follow up

44. Post-Operative Complications associated with a Posterior Capsular Rent: Early Complications Striate Keratopathy Corneal edema Glaucoma e.g, retained viscoelastic, pigment dispersion from excessive manipulation, vitreous in the angle etc. Uveitis Endophthalmitis Late Complications: Pseudophakic Bullous Keratopathy Glaucoma Epithelial downgrowth Increased risk of retina detachment

45. DROPPED NUCLEUS It is a posterior dislocation of nucleus into the vitreous cavity Dreaded complication Risk factors - Excessive infusion Gross manipulation Ultrasound repulsion Vitreous liquefaction Forward displacement of anterior vitreous

46. If nucleus falls back into the mid to anterior vitreous , the viscoelastic PAL technique done as long as the nucleus can be visualized ; 2 Techniques for levitating nucleus forward : Manual removal with a lens loop through an enlarged incision or Resume phacoemulsification (But not to be done in vitreous prolapse because vitreous incarceration by phaco tip may cause giant retinal tear) After anterior vitrectomy ,If nucleus can be safely supported by iris or by IOL or sheets glide scaffold , phacoemulsification can be resumed . If the entire nucleus is intact , difficulty in bringing forward through intact capsulorrhexis

47. If nucleus descends as far as mid or posterior vitreous or the retinal surface , it should be left alone Anterior vitrectomy done and remove accessible cortex vitreo retinal surgeon consultation is required.

48. REFERENCES : 1.Jaffe 2.steinert 3.Posterior capsular rent: Prevention and management. Indian journal of ophthalmology

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