• Retina/Vitreous

    Increased life expectancy concomitant with phacoemulsification’s enhanced safety and success have galvanized the popularity of cataract surgery. Consequently, pseudophakic retinal detachment (RD) has emerged as a relatively common entity distinct from phakic rhegmatogenous RD. The cumulative probability of RD is estimated at 0.27% during the first year after cataract surgery, and it continues to rise over time in a nearly linear manner to 1.79% at 20 years (Ophthalmology. 2006;113:2026-2032). Cortical remnants, posterior capsular opacification, and optical aberrations from the margins of an intraocular lens (IOL) can interfere with the visibility of retinal breaks. A substantial disparity in the presentation of retinal breaks, combined with their poor visibility, creates a dilemma for the retinal surgeon when it comes to choosing an optimal surgical intervention. Ideal management of pseudophakic RD primarily involves the affected eye, but the surgeon must also consider the risk factors, etiology, and various management techniques to prevent an RD in the fellow eye.

    Risk Factors

    Researchers have identified various independent risk factors for pseudophakic RDs. These include younger age (under 60 years), myopia with axial length greater than or equal to 25 mm, history of RD in the fellow eye, unplanned disruption of the posterior capsule, intraoperative vitreous loss, and incarceration of vitreous in the wound.1,2 There is an almost 6 times higher risk of pseudophakic RD in younger patients (Ophthalmology. 2006;113:2026-2032). Similarly there is a six fold increase in the incidence of pseudophakic RDs in individuals with axial length greater than or equal to 25 mm (J Cataract Refract Surg. 1988;14(6):624-632). A fivefold rise in pseudophakic RDs has been reported in cases complicated by the posterior capsular tear (Ophthalmology. 2006;113:2026-2032). There is conflicting evidence regarding the association between YAG (yittrium-aluminum-garnet) laser capsulotomy and pseudophakic RDs.4,5 In a recent population-based study, however, YAG laser capsulotomy was not found to be a significant risk factor for RD (Ophthalmology. 2006;113:2026-2032).

    Etiology

    The exact mechanism of retinal break formation in pseudophakic RDs remains unclear, and multiple theories have been postulated. Nevertheless, it is evident that certain physical and chemical changes occur in the vitreous after cataract surgery predisposing the eye to the formation of retinal breaks. The most noticeable change in the vitreous is the development of posterior vitreous detachment (PVD) or rapid progression of preexisting PVD.

    It has been suggested that several mechanical and chemical factors either singly or in combination initiate vitreous instability. Loss of dampening effect of the posterior protuberance of the crystalline lens, forward movement of the vitreous body, and traction on the peripheral retina after vitreous incarceration in the wound are the physical factors most likely to modify kinetics of the vitreous base (Surv Ophthalmol. 2003;48(5):467-487). Changes in the biochemical microenvironment of the vitreous and retina in pseudophakic eyes are known to occur as a result of lens cortical fibers leaking into the vitreous during cataract surgery (Exp Eye Res. 2005;80(3):337-347).

    It remains unclear how YAG laser capsulotomy facilitates the occurrence of RDs (Surv Ophthalmol. 2003;48(5):467-487). In a prospective study, incidence of PVD was found to be independent of YAG laser capsulotomy in the cohort of patients with ECCE and IOLs (J Cataract Refract Surg. 2003;29(5):930-934). Possible explanations for retinal break formation following laser capsulotomy include rupture of the anterior vitreous face or acoustic trauma to the vitreous body by waves, which alters the dynamics of the vitreous body, with resultant retinal tear formation (Surv Ophthalmol. 2003;48(5):467-487).

    Diagnosis

    Pseudophakic RDs either progress rapidly due to continuous vitreous traction or had already progressed to involving the macula at their presentation. Patients with pseudophakic RDs may present with typical symptoms of flashes, floaters, or peripheral field loss. If refraction after cataract surgery fails to improve vision, this should alert the examiner to dilate the pupils and rule out RD.The success of RD repair depends predominantly on early diagnosis and accurately locating the retinal breaks. This requires a meticulous fundus examination by all available means such as indirect ophthalmoscopy, slit-lamp biomicroscopy, and contact lens examination. Dynamic scleral depression during indirect ophthalmoscopy may help the surgeon to see the retinal breaks and distinguish them from other lesions. Typically, retinal breaks in pseudophakic RDs are multiple, small, and located anterior to the equator near the ora serrata, with the majority being found in the superotemporal quadrant (Surv Ophthalmol. 2003;48(5):467-487). Using ultrasonography and newer retinal imaging techniques in day-to-day practice may also assist in the diagnosis of pseudophakic RDs.

    Management

    The preferred surgical method for managing pseudophakic RDs remains the surgeon’s prerogative. However, as more data on the management of pseudophakic RDs have come to light, guidelines have evolved that may help when choosing a surgical intervention. An asymptomatic small peripheral RD with a demarcation line may be managed conservatively with periodic observation. Retinal breaks with small peripheral RDs can be managed with laser retinopexy or cryotherapy.

    Pneumatic Retinopexy
    The vast majority of pseudophakic RDs require some form of surgical intervention. Pneumatic retinopexy has been widely applied in the management of selected cases of phakic RDs; however, its role in the treatment of pseudophakic RDs is less clear. Ideal cases for pneumatic retinopexy include phakic eyes with a superiorly located single tear not exceeding 1 clock hour; or multiple superior retinal breaks dispersed within 1 clock hour; absence of advanced grade (C and D) proliferative vitreoretinopathy (PVR); absence of lattice degeneration in other areas; and absence of uncontrolled glaucoma. Pneumatic retinopexy may be precluded by cloudy media, inferior location of retinal breaks, advanced PVR, and the patient’s inability to maintain his or her position during the postoperative period. The procedure can be performed in the office under local anesthesia by injecting sulfur hexafluoride (SF6) or perfluoropropane (C3F8) gas into the vitreous cavity and instructing the patient to adopt a position that places the retinal tear superiorly for an effective tamponade (“bubble on the trouble???). Fortunately, a failed pneumatic retinopexy does not jeopardize the success of future scleral buckling or vitrectomy if warranted (Ryan SJ, ed. Retina. 4th ed. Philadelphia, PA: Elsevier Mosby; 2006:2071-2083).

    The literature documents anatomical and functional outcomes in combined phakic, aphakic, and pseudophakic patients following pneumatic retinopexy. However, there is insufficient data on the role of pneumatic retinopexy used exclusively in the treatment of pseudophakic RDs.9-11 Nevertheless, evidence indicates that the primary anatomical success rate of pneumatic retinopexy in pseudophakic RDs is at least 60%.9-11 Careful case selection significantly increases the success rate of pneumatic retinopexy. A final anatomical success rate of 97% or better may be achieved in these patients after subsequent buckling or vitrectomy procedures. Failure of pneumatic retinopexy has been attributed to missed retinal tears or formation of new retinal breaks away from the site of the endotamponade.

    Scleral Buckling and Vitrectomy
    Scleral buckling (SB) is an established technique for the treatment of rhegmatogenous RDs. Recent advances in pars plana vitrectomy (PPV) techniques have encouraged retinal surgeons to expand the role of vitrectomy in the management of complicated and uncomplicated pseudophakic RDs. Several published reports compare anatomical outcomes following different surgical techniques in the management of pseudophakic RDs (Ophthalmology. 2006;113(10):1724-1733).

    A recent meta-analysis on the management of uncomplicated pseudophakic RDs revealed anatomical success rates of 81% following SB, 91% after PPV, and 97% for the combined technique of PPV with SB after a single surgery. This study, however, had limitations inherent in meta-analysis such as geographic diversity of patient population, multiplicity of surgeons, and nonrandomization. Brazitikos et al conducted a randomized clinical trial and demonstrated a similar advantage of primary PPV over SB surgery in patients with early pseudophakic RDs (Retina. 2005;25(8):957-964). The retina was attached in 83% and 94% in the SB and PPV groups respectively following single surgery. Overall, the primary surgical success rate following SB varies from 61% to 97% in uncomplicated pseudophakic RDs, while the comparable anatomical outcome following PPV ranges from 84% to 98%. PPV offers the advantages of removing posterior capsular opacity, clearing vitreous debris, detecting unseen breaks, releasing vitreous traction, and removing gliogenic cells without inducing significant changes in refractive error postoperatively. Application of PPV in pseudophakic RDs is limited by inadequate endotamponade to inferior breaks in the absence of an FDA-approved heavy tamponade, difficulties in postoperative positioning, and restrictions on air travel.

    Disruption of the posterior capsule during surgery may be complicated by moisture globules forming on the posterior surface of the IOL during air–fluid exchange, which may significantly limit visibility of the retina. Moisture drops can be coalesced with balanced salt solution in polymethylmethacrylate IOLs, while a viscoelastic agent or semifluorinated alkanes such as perfluorohexyloctane (F6H8) may be needed to eliminate droplets on silicone lenses (Surv Ophthalmol. 2003;48(5):467-487).

    Complicated Pseudophakic Retinal Detachments
    Data on the management of complicated pseudophakic RDs is limited. However, it can be extrapolated that management of complex pseudophakic RDs would not be significantly different from other complicated rhegmatogenous RDs. Complicated pseudophakic RDs with PVR grades C and D merit PPV for adequate release of traction and establishing an efficient endotamponade. Because of their buoyancy, silicone oil and intraocular gases such as SF6 and C3F8 provide an effective tamponade to superiorly located retinal breaks.14,15 The advent of F6H8 and partially fluorinated alkane perfluorohexylethan (O62) show promise in providing an effective tamponade for inferiorly located retinal breaks following vitrectomy.16,17

    Management of advanced PVR, despite progress in vitrectomy techniques and instrumentation, remains a challenge. In spite of our enhanced understanding of the molecular biology of PVR, a clinically acceptable chemical adjuvant for prevention of PVR is still in the early stages of development. In a recent randomized clinical trial, intravitreal infusion of combined 5-fluorouracil and low-molecular-weight heparin did not improve anatomical and functional success rates of primary RDs undergoing vitrectomy. A worse visual outcome was observed in patients with macular-sparing RDs in this study (Ophthalmology. 2007;114:698-704). In another randomized clinical trial, infusing adjuvant therapy of combined 5-fluorouracil and low-molecular-weight heparin did not significantly improve primary anatomical and visual outcomes in patients with established PVR (grade C). However, secondary macular pucker occurred less often in the treatment group (Ophthalmology. 2004;111:2240-2245).

    Conclusion

    Pseudophakic RD has emerged as a relatively common entity, and its management requires a different strategy than its phakic counterpart for long-term success. A multiplicity of retinal breaks, poor visibility of breaks, a threatened macula, or macular detachment on presentation requires the surgeon to adopt a surgical strategy that provides a superior primary reattachment rate by accurately locating all the breaks and closing them permanently. Promising advances in vitrectomy techniques suggest it is an optimal intervention for accomplishing these goals in pseudophakic RDs.

    References

    1. Erie JC, Raecker MA, Baratz KH, et al. Risk of retinal detachment after cataract extraction, 1980-2004: a population-based study. Ophthalmology 2006;113:2026-2032.
    2. Lois N, Wong D. Pseudophakic retinal detachment. Surv Ophthalmol. 2003;48(5):467-487.
    3. Davison JA. Retinal tears and detachments after extracapsular cataract surgery. J Cataract Refract Surg. 1988;14(6):624-632.
    4. Javitt JC, Tielsch JM, Canner JK, et al. National outcomes of cataract extraction. Increased risk of retinal complications associated with Nd:YAG laser capsulotomy. The Cataract Patient Outcomes Research Team. Ophthalmology. 1992;99(10):1487-1497; discussion 1497-1498.
    5. Olsen G, Olson RJ. Update on a long-term, prospective study of capsulotomy and retinal detachment rates after cataract surgery. J Cataract Refract Surg. 2000;26(7):1017-1021.
    6. Neal RE, Bettelheim FA, Lin C, et al. Alterations in human vitreous humour following cataract extraction. Exp Eye Res. 2005;80(3):337-347.
    7. Sheard RM, Goodburn SF, Comer MB, et al. Posterior vitreous detachment after neodymium:YAG laser posterior capsulotomy. J Cataract Refract Surg. 2003;29(5):930-934.
    8. Brinton DA, Lit ES: Pneumatic retinopexy. In: Ryan SJ, ed. Retina. 4th ed. Philadelphia, PA: Elsevier Mosby; 2006:2071-2083.
    9. Tornambe PE, Hilton GF, Brinton DA, et al. Pneumatic retinopexy. A two-year follow-up study of the multicenter clinical trial comparing pneumatic retinopexy with scleral buckling. Ophthalmology. 1991;98(7):1115-1123.
    10. Grizzard WS, Hilton GF, Hammer ME, et al. Pneumatic retinopexy failures. Cause, prevention, timing, and management. Ophthalmology. 1995;102(6):929-936.
    11. Eter N, Böker T, Spitznas M. Long-term results of pneumatic retinopexy. Graefe’s Arch Clin Exp Ophthalmol. 2000;238(8):677-681.
    12. Arya AV, Emerson JW, Engelbert M, et al. Surgical management of pseudophakic retinal detachments. A meta-analysis. Ophthalmology. 2006;113(10):1724-1733.
    13. Brazitikos PD, Androudi S, Christen WG, Stangos NT. Primary pars plana vitrectomy versus scleral buckle surgery for the treatment of pseudophakic retinal detachment. A randomized clinical trial. Retina. 2005;25(8):957-964.
    14. Silicone Study Group. Vitrectomy with silicone oil or sulfur hexafluoride gas in eyes with severe proliferative vitreoretinopathy: results of a randomized clinical trial. Silicone Study Report 1. Arch Ophthalmol. 1992;110(6):770-779.
    15. Silicone Study Group. Vitrectomy with silicone oil or perfluoropropane gas in eyes with severe proliferative vitreoretinopathy: results of a randomized clinical trial. Silicone Study Report 2. Arch Ophthalmol. 1992;110(6):780-792.
    16. Kirchhof B, Wong D, Van Meurs J, et al. Use of perfluorohexyloctane as a long-term internal tamponade agent in complicated retinal detachment surgery. Am J Ophthalmol. 2002;133(1):95-101.
    17. Hoerauf H, Roider J, Kobuch K, Laqua H. Perfluorohexylethan (O62) as ocular endotamponade in complex vitreoretinal surgery. Retina. 2005;25(4):479-488.
    18. Wickham L, Bunce C, Wong D, et al. Randomized controlled trial of combined 5-fluorouracil and low-molecular-weight heparin in the management of unselected rhegmatogenous retinal detachments undergoing primary vitrectomy. Ophthalmology. 2007;114(4):698-704.
    19. Charteris DG, Aylward GW, Wong D, et al, for the PVR Study Group. A randomized controlled trial of combined 5-fluorouracil and low-molecular-weight heparin in the management of established proliferative vitreoretinopathy. Ophthalmology. 2004; 111(12):2240-2245.

    Author Disclosure

    Drs. Arya and Adelman state that they have no financial relationship with the manufacturer of any product discussed in this article or with the manufacturer of any competing product.