Management of Dropped Nucleus and Retained Lens Fragment

Dhanashree Ratra, Vineet Ratra,Sukant Pandey


Introduction:


Drooped nucleus and retained lens fragment is a complication not so rare in clinical practise. In the era where cataract surgery is being performed for visual enhancement rather than visual rehabilitation, management of dropped nucleus saves patient from unnecessary anxiety and hastens visual recovery.
In this chapter risk factors, timing of surgery, various approach for removal of lens will be discussed.

Incidence:


Dropped nucleus and cortical remnants, occur more frequently in phocoemulsification than other techniques of cataract surgery 1,2 . Surveys in developed nations like U.S and U.K have reported incidences of 0.3 % 1 and 1.1 % respectively. In India, few studies have quoted its incidence to be around 0.8 %. [3]

Risk Factors:


The exact cause for posterior displacement of nucleus is difficult to determine but certain conditions predisposes for complication4

Preventive Steps in High risk cases:

Primary Management by the Anterior Segment Surgeon:


First step in management is to recognize posterior capsular (PC) tear early. Early recognition reduces the chances of vitreous loss and dropped fragment.
Signs of Posterior Capsular rupture: [5]

1. Sudden deepening of anterior chamber, with slight dilation of pupil.
2. Sudden, transitory appearance of a red reflex peripherally.
3. Newly apparent inability to rotate a previously mobile nucleus.
4. Excessive lateral mobility or displacement of the nucleus.
5. Excessive tipping of one pole of the nucleus.
6. Partial descent of the nucleus into a more posterior position.

Next step comprises of judging the situation and deciding on further course of surgery.

1. If retained nucleus is small and no vitreous prolapse with adequate capsular support, then continuing with the phaco emulsifictation depends upon surgeons’ choice and comfort. Few points to remember:


a) Primary objective is retrieval of retained nucleus fragment without aspirating vitreous.
b) Retained fragments can be brought in Anterior chamber by the use of Ophthalmic Viscoelastic Device (OVD).
c) Bottle height should be lowered and vaccum reduced.
d) Avoiding sculpting and rotating the nucleus. Avoid using aspiration near the PC tear.
e) Sheet’s glide can be used over the PC rent to complete the phaco emulsification.

2.If vitreous loss has occurred then it is best to convert it to conventional EECE incision and try to remove as much nucleus as possible with the help of OVD by displacing the retained fragment in the AC.

3. In case of a posterior displacement of the fragment, in certain cases where it is at anterior hyloid phase, PAL (Posterior assisted Levitation) deviced by Kelman and modified by Packard  can be utilized.5  In this technique the fragments are approached from Pars plana route and a Dispersive Viscoelastic is injected behind it. Now manually with the tip of injecting cannula the retained fragments are manoeuvred into AC.

In case of vitreous loss we could utilize VISCO Trap technique proposed by Chang   to trap the retained fragments , epinucleus  and cortex in AC by the use of dispersive viscoelastic and then perform the bimanual vitectomy along with supplementation of OVD  to remove the vitreous and retained fragments.5

If Amount of retained nuleus is small where it will not require further intervention then placing of Anterior/ Posterior Chamber IOL is recommended. If management requires Vitrectomy then IOL placement should be differed.

Complications:


Depending on the size of retained lens fragments, Patients present with varying degrees of inflammation.  Clinical signs may include corneal oedema, glaucoma, uveitis and vitreous opacities causing profound visual loss. Frequently however, signs are mild especially in the immediate postoperative interval. 6 

Do’s For anterior segment surgeon once lens drop is recognized:

1. Easily accessible fragments should be removed.
2. Perform anterior vitrectomy to avoid vitreous prolapse.
3. Tight wound closure with suture and viscoelastic removal should be done.
4. Prescribe frequent postoperative topical steroids and IOP lowering agent.
5. Provide referral for prompt VR consultation.

Timing of removal:


If VR back up is available at the hospital it is best to remove the fragments/ lens in the same sitting. The reasons are:
1) Prevents the patient from undergoing two surgeries.
2) Chance of post op rise in pressure and inflammation are reduced.
3) Saves patient from unnecessary anxiety.

Problems with Same Sitting removal:

1) Anaesthetic have to be supplemented on the table by giving a posterior subtenon injection.
2) Pupils is generally small hampering the view.
3) Corneal odema may set in causing difficulty in visualization.

If patient is being referred to VR surgeon then a thorough pre operative assessment should be done before deciding upon timing of surgery. If other cornea is clear then it should be done within 1-2 weeks. [8]

 

Pre Operative assessment:


Before taking up the patient for surgery a complete ophthalmological assessment should be performed, comprising of :

Vitreous haemorrhage can also be picked up.

The clinical findings and options of treatment should be discussed in detail with the patient.
A written consent in this regard should be taken.

Management Option:


 

Surgical Treatment:


Numerous techniques for removal of nucleus have been described in literature. Ideal technique depends upon availability of instrumentation, size and hardness of nucleus and surgeon preference.
Principally it comprises of following step: [11]

 

STEP 1: Pars plana Vitrectomy

Key Points :
1. Remove all the vitreous from Anterior Chamber/ primary cataract wound (if present)
2. Intra vitreal Triamicilone could be utilized for better visualization of vitreous.
3. All the vitreous attachment to the nucleus should be removed.
4. If fragmatome is being used then induction of PVD is must and vitreous base should be trimmed to extent possible.

STEP 2: REMOVAL OF NUCLEUS

It depends upon type of nucleus:

a) Soft nucleus:

Most of the times it can be removed by cutter itself.

Key Points :
1) Cut rate should be low near 600-800 cuts per minute with suction on the higher side.
2) Few drops of PFCL can be used as a cushion to prevent the nucleus pieces falling directly over the macula and causing damage to it.
3) Light pipe can be used to crush the nucleus against the cutter probe for easy cutting.

b) Hard Nucleus:

1) Using Fragmatome/ Phaco Tip without Sleeve:

Key Points :

  • Perform adequate vitrectomy prior to use of an ultrasonic fragmatome to avoid vitreous fibrils being sucked into the fragmatome hand piece, causing vitreous traction. Using triamcinolone acetonide to stain the vitreous ensures easy visualization.
  •  Reducing fragmentation power to only 5 -10 %  facilities nuclear extraction by continuous occlusion of the suction port and avoidance of projectile fragments.[12]
  •  Using a small bubble of PFCL for protecting retina from projectile nuclear fragments.

2) Delivering Nucleus via limbal route:

  • Elevating it with using Active suction with the hard tip flute cannula and bringing it to anterior chamber.
  • Using a pick/MVR blade to elevate it in the anterior chamber. The major disadvantage being it may cause damage to underlying retina.
  • Using PFCL to float it upto pupillary plane and then delivering the nucleus via limbal route. The major advantage being all the nuclear fragments floats above the bubble and can be removed, it can be also utilized with accompanying retinal detachment. The caution has to be taken as nuclear fragments tends to slip over the meniscus to the periphery, hence meticulous examination of periphery also help in visualization and removal of these fragments. [13]

STEP 3: Peripheral Examination by indentation helps us to locate any pre existing breaks or localize any unknown breaks caused during the surgery and manage them by barraging them with laser intra operatively thus reducing chances of post operative retinal detachment.[14]

STEP 4: IOL choice:

Depending upon presence of adequate capsular support an in the bag or sulcus placement of IOL can be attempted.  For sulcus fixation a 3 piece IOL or PMMA IOL is preferred over single piece lens. [15]
In case adequate support is not available then sclera fixated/ glued IOL can be placed or  3 piece open looped anterior chamber IOL can also be placed.

Conclusion:


The current instrumentation and surgical technique has rendered the management of dislocated nucleus very successful with very low complication rates, correct patient selection and discussion of pros and cons of surgery forms an important part of management. Correct treatment at appropriate time is one of the most important key in management of posterior dislocated nucleus.

 

Biblography:

1) Leaming DV. Practice and preferences of ASCRS members – 2003 survey. J Cataract Refract Surg. 2004;3:892-900.
2) von Lany H, Mahmood S, James CR, et al. Displacement of nuclear fragments into the vitreous complicating phacoemulsification surgery in the UK: clinical features, outcomes and management. Br J Ophthalmol. 2008;92(4):493-495.
3)  A Mathai, R Thomas. Incidence and management of posteriorly dislocated nuclear fragment following phacoemulsification. IJO 1999;47(3):173-176
4) Aasuri MK, Kompella VB, Majji AB. Risk factors for and management of dropped nucleus during
phacoemulsification. J Cataract Refract Surg 2001; 27: 1428-1432
5) Chang DF. Viscoelastic levitation of nuclear fragments using viscoat after posterior capsular rupture. J.Cataract Refract Surg 2003; 29:1860-1865
6)  Scott IU, Flynn HW, Jr, Smiddy WE, et al. Clinical features and outcomes of pars plana vitrectomy in patients with retained lens fragments. Ophthalmology 2003; 110: 1567-1572
7) Blodi BA, Flynn JR, Blodi CF, et al. Retained nuclei after cataract surgery. Ophthalmology 1992; 99:41-44
8) Vilar NF, Flynn HW Jr, Smiddy WE, et al. Removal of retained lens fragments after phacoemulsification reverses secondary glaucoma and restores visual acuity. Ophthalmology 1997; 104:787-791;
9) Stilma JS, Van der Sluijs FA, van Meurs JC Mertens DAE. Occurrence of retained lens fragments after phacoemulsification in The Netherlands. J Cataract Refract Surg 1997; 23: 1177-1182
10 ) Bessant D.A.R., Sullivan PM, Aylward GW. The management of dislocated lens material after
phacoemulsification. Eye 1998, 12:641-645
11) Gilliland GD, Hulton WL, Fuller DG. Retained intravitreal lens fragments after cataract surgery.
Ophthalmology 1992;99:1262-1267;
12) Margherio RR, Margherio AR, Pendergast SD, et al. Vitrectomy for retained lens fragments after
phacoemulsification. Ophthalmology 1997;104: 1426-1432
13) Shapiro M.J; Resnick K.I; Kim. S. H; Weinberg. A Management of Dislocated Crystalline Lens with a Perfluoro, carbon Liquid. Am. J. Ophthalmol 112; 401; 1991
14) Oruc S, Kaplan HJ. Outcome of vitrectomy for retained lens fragments after phacoemulsification. Ocular Immunol Inflamm 2001; 9 :41-47
15)Wagoner MD, Cox TA, Ariyasu RG, Jacobs DS, Karp CL Intra ocular lens implantation in the absence of capsular support; a report by the American Academy of Ophthalmology: Ophthalmology 2003;110: 840-859