Managing the Retinal Complications Of Cataract Surgery

How to respond when lens fragments drop and other troubling events occur.

KEVIN K . SUK, MD, WITH TIMOTHY G. MURRAY, MD, MBA , FACS

Over the past several years, improvements in surgical technique and platform as well as advances in intraocular lens technology have allowed cataract surgeons to deliver extraordinary visual outcomes for most patients. Toric and multifocal IOLs as well as femtosecond laser-assisted surgery have elevated the precision of cataract surgery to nearly that of a refractive procedure. Accordingly, it is not unexpected for patients to demand similar refractive outcomes after cataract surgery. Any deviation from these high expectations can be disappointing for both the patient and surgeon.

Unfortunately, unexpected events do occur intraoperatively as well as postoperatively. Some of these complications can limit the final visual outcome and may require referral to a vitreoretinal surgeon. How the cataract surgeon handles these complications can dramatically affect the final surgical and visual outcome. Here, we will discuss common cataract surgery complications and provide guidance on how to resolve them.

Retained Lens Fragments

The most common intraoperative complication is rupture of the posterior capsule, the incidence of which has ranged from 0.29% to 2.1% in published studies.^1-6 Some of these cases are further complicated by posterior dislocation of the lens fragments, with a reported incidence between 0.1% and 1.1%.^7,8 Although not all cases require vitrectomy, retained lens fragments can lead to other ocular complications including glaucoma, corneal edema and uveitis. Pars plana vitrectomy has been shown to be effective in removing retained fragments and alleviating these complications.

Most patients recover good vision after vitrectomy to remove retained lens fragments. However, retinal complications, including retinal detachment and cystoid macular edema (CME), can severely limit visual recovery.

Retinal detachment occurs at a higher rate after vitrectomy for retained lens fragments than after vitrectomy for other indications.⁹ The higher incidence can be attributed to retinal tears caused by undue traction on the peripheral retina from vitreous prolapse into the anterior chamber or after inadequate anterior vitrectomy. Traction on the peripheral retina also occurs when the cataract surgeon attempts to remove lens fragments too aggressively from the vitreous cavity.

Figure 1. A three-piece IOL is placed in the ciliary sulcus and the optic captured, helping to compartmentalize the anterior chamber.

CME Risk in Aphakic Eyes

Postoperative CME also occurs more frequently after vitrectomy for retained lens fragments than after uneventful cataract surgery.¹⁰ The risk is higher when the eye is left aphakic or if an anterior chamber IOL is placed at the end of complicated cataract surgery, which may reflect the level of trauma during the operation.^10,11 A posterior chamber IOL may also incite less inflammation and may be a barrier to inflammatory mediators reaching the macula.

Thus, from a vitreoretinal surgeon’s standpoint, the goal of cataract surgery complicated by dropped lens fragments is to minimize traction on the peripheral retina, to remove residual lens material from the anterior chamber and to place the IOL in the sulcus (Figure 1). It is important to minimize trauma to the corneal endothelium, because corneal decompensation can make it difficult to identify retinal breaks before and during vitrectomy.

Signs of Posterior Capsule Rupture

The first step is to recognize the presence of a posterior capsule rupture. The signs may be subtle. A sudden change in anterior chamber depth or pupil size may indicate a sudden movement of fluid through a posterior capsule defect.

The next step is to recognize any disruption in the anterior hyaloid face and if the vitreous has prolapsed into the anterior chamber. Loss of followability and phaco efficiency, a peaked pupil or abnormal pupil movement may signal the presence of vitreous. Once you recognize a posterior capsule rupture, stop the phacoemulsification, lower the infusion pressure and assess the situation without removing the instruments from the eye. Removing the phaco instrument at this juncture can cause the anterior chamber to collapse or fluctuate, which can further extend the tear and allow more vitreous to move forward. A cohesive viscoelastic injected through the side incision before removing the phaco instrument from the eye stabilizes the anterior chamber and pushes the vitreous back.

Once you recognize the presence of vitreous in the anterior chamber, perform an anterior vitrectomy. Phacoemulsification is inefficient and dangerous when lens material has mixed with vitreous. Vitreous displaces the nucleus and is preferentially attracted to the phaco tip. Aspiration of the anterior vitreous in this setting transmits tractional forces to the peripheral retina, increasing the risk for retinal tears.

Performing Anterior Vitrectomy

During anterior vitrectomy, debulk the anterior hyaloids and sever any attachments of the vitreous to the anterior chamber and lens material. Diluted preservative-free triamcinolone acetonide is helpful in identifying and highlighting the vitreous. Also, periodically inject a dispersive viscoelastic between the lens material and the posterior capsule defect to lift the nucleus and to serve as a barrier between the lens and the vitreous. Use low power to avoid washing out the viscoelastic and to limit hydration of the vitreous.

Despite these measures, lens material can fall into the vitreous cavity or become “lost.” As tempting as it may be, do not attempt to retrieve lens fragments that pass behind the posterior lens capsule. The infusion from the phaco tip will push the lens material deeper into the vitreous cavity while preferentially aspirating the vitreous. Retinal tears are likely to occur in this situation.

Most experienced cataract surgeons recognize the danger of chasing lens fragments into the vitreous cavity and attempt to bring the lens material forward by injecting viscoelastic underneath the lens material. This can be quite difficult, depending on the size of the lens material, the amount of vitreous surrounding it and how far posteriorly it has fallen, due to the steep angle of approach needed with the viscoelastic cannula.

Alternatively, some authors have described bringing the lens material forward from a posterior approach. Termed posterior assisted levitation (PAL), this maneuver involves either using a cyclodialysis spatula or other instrument from a pars plana incision to mechanically push the lens material forward.^12,13 Others have described injecting a dispersive viscoelastic through the pars plana to push the lens material forward.¹⁴

A few case series have advocated PAL as a safe and effective way to manage these complex cases. However, most of these are small case series colored by selection bias.^13-15 And, although it may be successful in select cases and in select hands, most usually perform PAL with poor visualization of the peripheral retina. At this point in the surgery, the pupil is typically miotic, and lens material and vitreous obscures visualization of the lens fragment and the instrument inserted through the par plana. Excessive manipulation of instruments in the anterior vitreous without proper visualization of the peripheral retinal can increase the risk of retinal tears and subsequent retinal detachment.

Figure 2. A large nuclear fragment is removed with a fragmatome after a complete vitrectomy is performed to sever all vitreous attachments to the lens.

Figure 3. Securing the main corneal incision with a 10-0 nylon suture at the conclusion of surgery helps prevent anterior chamber collapse and iris prolapse during subsequent vitrectomy.

Prompt Referral is the Best Option

The vitreoretinal surgeon has the advantage of direct visualization of the peripheral retina and a much faster vitrectomy cut rate when removing any “lost” lens material (Figure 2). Moreover, not all retained lens fragments require removal and can be managed medically in the absence of other complications such as increased IOP, inflammation, CME or corneal edema.

At the conclusion of surgery, we advise the cataract surgeon to close the main incision with a suture (Figure 3). This helps the vitreoretinal surgeon by preventing loss of anterior chamber integrity and iris prolapse when inserting small-gauge trocars, and during vitrectomy. After surgery, refer the patient to a vitreoretinal surgeon as soon as possible, preferably within a week. Although the timing of vitrectomy for retained lens material is controversial, earlier referral may allow timely detection of other complications such as a retinal detachment or endophthalmitis.

A suprachoroidal hemorrhage is another unexpected complication of cataract surgery that requires prompt referral to a vitreoretinal surgeon. In some ways, intraoperative management is straightforward. Persistent shallowing of the anterior chamber usually heralds a suprachoroidal hemorrhage. Shadowing of the red reflex may appear and intraocular contents may extrude from the eye.

At the first sign of this complication, the surgeon needs to stop and close the eye as soon as possible after injecting viscoelastic into the anterior chamber. This can limit the extent of the choroidal detachment, which has prognostic implications. The surgeon should not create sclerotomies to attempt to drain the hemorrhage intraoperatively, as this will only extend the hemorrhage. The vitreoretinal surgeon can better drain the hemorrhage once the blood has liquefied, usually in 7-14 days.

Postoperative Complications

Besides unexpected intraoperative events during cataract surgery, the cataract surgeon encounters unexpected events postoperatively, when visual outcomes deviate from the expected. To this end, preoperative evaluation of the retina is important. Spectral domain optical coherence tomography can reveal subtle pathology such as epiretinal membranes, vitreomacular traction, macular degeneration, macular edema and retinal atrophy.

Fluorescein angiography is helpful in evaluating the extent and severity of diabetic retinopathy, which may require treatment before cataract surgery. It is well documented that cataract surgery can exacerbate diabetic retinopathy, and one should treat diabetic macular edema aggressively before surgery. Angiography can also show macular ischemia, which would limit visual recovery. With prior knowledge of retinal pathology, you can inform the patient and temper his or her expectations.

The vast majority of patients enjoy excellent outcomes after cataract surgery. Unfortunately, unexpected events can occur, but good visual outcomes are still within reach with proper and timely management of vitreoretinal complications. OM

References

1. Narendran N, Jaycock P, Johnston RL, et al. The Cataract National Dataset electronic multicentre audit of 55,567 operations: risk stratification for posterior capsule rupture and vitreous loss. Eye (Lond), 2009;23:31-37.

2. Muhtaseb M, Kalhoro A, Ionides A. A system for preoperative stratification of cataract patients according to risk of intraoperative complications: a prospective analysis of 1441 cases. Br J Ophthalmol. 2004;88:1242-1246.

3. Misra A, Burton RL. Incidence of intraoperative complications during phacoemulsification in vitrectomized and nonvitrectomized eyes: prospective study. J Cataract Refract Surg. 2005;31:1011-1014.

4. Agrawal V, Upadhyay J. Indian Cataract Risk Stratification Study group. Validation of scoring system for preoperative stratification of intra-operative risks of complications during cataract surgery: Indian multi-centric study. Indian J Ophthalmol. 2009;57:213-215.

5. Ang GS, Whyte IF. Effect and outcomes of posterior capsule rupture in a district general hospital setting. J Cataract Refract Surg. 2006;32:623-627.

6. Zaidi FH, Corbett MC, Burton BJ, et al. Raising the benchmark for the 21st century — the 1000 cataract operations audit and survey: outcomes, consultant-supervised training and sourcing NHS choice. Br J Ophthalmol. 2007;91:731-736.

7. Stilma JS, van der Sluijs FA, van Meurs JC, Mertens DA. Occurrence of retained lens fragments after phacoemulsification in The Netherlands. J Cataract Refract Surg. 1997;23:1177-1182.

8. Pande M, Dabbs TR. Incidence of lens matter dislocation during phacoemulsification. J Cataract Refract Surg. 1996; 22:737–742.

9. Smiddy WE, Guererro JL, Pinto R, Feuer W. Retinal detachment rate after vitrectomy for retained lens material after phacoemulsification. Am J Ophthalmol. 2003;135:183-187.

10. Cohen SM, Davis A, Cukrowski C. Cystoid macular edema after pars plana vitrectomy for retained lens fragments. J Cataract Refract Surg. 2006;32:1521-1526.

11. Scott IU, Flynn HW Jr, Smiddy WE, Murray TG, Moore JK, Lemus DR, Feuer WJ. Clinical features and outcomes of pars plana vitrectomy in patients with retained lens fragments. Ophthalmology. 2003;110:1567-1572.

12. Packard RBS, Kinnear FC. Manual of Cataract and Intraocular Lens Surgery. Edinburgh, UK; Churchill Livingstone. 1991; 47.

13. Por YM, Chee SP. Posterior-assisted levitation: outcomes in the retrieval of nuclear fragments and subluxated intraocular lenses. J Cataract Refract Surg. 2006; 32:2060-2063.

14. Chang DF, Packard RB. Posterior assisted levitation for nucleus retrieval usingViscoat after posterior capsule rupture. J Cataract Refract Surg. 2003;29:1860-1865.

15. Lifshitz T, Levy J. Posterior assisted levitation: long-term follow-up data. J Cataract Refract Surg. 2005; 31:499-502.

Kevin Suk, MD, is a retina specialist in private practice at the Retina Institute in Arcadia, Calif. He can be reached via e-mail at kevinksuk@gmail.com. Timothy G. Murray is a retina specialist at Murray Ocular Oncology and Retina in Miami.