REVIEW URRENT C OPINION
Subjective complaints after cataract surgery: common causes and management strategies Christopher T. Hood and Alan Sugar
Purpose of review To describe the common causes of, and management strategies for, nonrefractive subjective visual complaints after cataract surgery. Recent findings Over the past decade, clinical observations and ray-tracing models have greatly increased our understanding of positive and negative dysphotopsias after cataract surgery. The primary factor behind positive dysphotopsias is the use of high refractive index square-edge intraocular lenses (IOLs). Primary and secondary factors that underlie negative dysphotopsias are now better characterized, which has led to successful interventions including IOL exchange and Nd:YAG laser anterior capsulotomy. Summary Positive and negative dysphotopsias occur after implantation of monofocal IOLs, and can rarely be disabling to patients. Visual complaints after multifocal IOL implantation are more common than after monofocal IOL implantation, but still rarely require significant intervention. A better understanding of the risk factors and optical causes of dysphotopsias will allow for IOL design and patient selection that maximize satisfaction after cataract surgery. Keywords cataract surgery, intraocular lenses exchange, negative dysphotopsia, positive dysphotopsia, subjective complaints
INTRODUCTION
BACKGROUND
Modern cataract surgery is the most commonly performed surgery in the USA and worldwide, and has an extremely high success rate in improving vision and quality of life. In a small fraction of patients, however, optical effects thought to be due to the implantation of intraocular lenses (IOL) lead to subjective visual complaints, including glare, halos, streaks, starbursts, shadows, and haze. Although these side-effects are usually readily tolerable to most patients, they are rarely more disabling than the preoperative state and, therefore, warrant management. This review will summarize the potential causes, and management strategies for, subjective complaints after cataract surgery, focusing on recent publications. Uncorrected refractive error and posterior capsular opacity, the two most common causes of visual disturbance after routine cataract surgery, will not be addressed. Visual complaints after multifocal IOL implantation will be discussed, but the focus will be on dysphotopsias in the setting of routine cataract surgery with monofocal IOL implants.
The term dysphotopsia was first used by Tester et al. [1] to describe a variety of undesired visual phenomena in both phakic and pseudophakic patients. Since their initial description, the terms positive and negative pseudophakic dysphotopsia have gained acceptance among clinicians. Positive dysphotopsias are defined as bright artifacts and include symptoms of arcs, streaks, rings, and halos. Negative dysphotopsias are perceived as shadows or dark areas, usually in the temporal visual field. Rarely, both types can be present simultaneously [2]. Both phenomena are thought to result from unwanted patterns superimposed on the retina, and may only be present under certain lighting Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA Correspondence to Alan Sugar, University of Michigan Kellogg Eye Center, 1000 Wall St., Ann Arbor, MI 48105, USA. Tel: +1 734 763 5506; fax: +1 734 936 2340; e-mail: [email protected] Curr Opin Ophthalmol 2015, 26:45–49 DOI:10.1097/ICU.0000000000000112
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Cataract surgery and lens implantation
KEY POINTS Although modern cataract surgery is extremely successful, dysphotopsias after implantation of IOLs occur and can rarely be disabling to patients and require intervention. Subjective visual complaints are more common after implantation of multifocal IOLs compared with monofocal IOLs. Optical modeling and clinical observations have better elucidated the mechanisms underlying both positive and negative dysphotopsias after implantation of monofocal IOLs. Surgical intervention, including IOL exchange, piggyback IOLs, and Nd:YAG laser anterior capsulotomy, may be successful in reducing or eliminating dysphotopsias. A better understanding of the risk factors and optical causes of dysphotopsias will allow for optimized IOL designs and patient selection that may eliminate subjective complaints after cataract surgery.
conditions or for certain locations of light sources (for example, a source in peripheral visual field). The overall incidence of pseudophakic dysphotopsias identified by unsolicited voiced complaints has been reported to be relatively rare [2], but given the prevalence of cataract surgery, these patients will be encountered in the routine practice of most cataract surgeons. Other authors have demonstrated that, if specifically questioned about symptoms, pseudophakic dysphotopsias may in fact be much more common, with an incidence of 33–78% [1,3,4]. Importantly for the clinician, symptoms of dysphotopsia were found to be negatively correlated with satisfaction and visual function in patients who underwent uneventful cataract surgery with good corrected visual acuity [5 ,6]. For the cataract surgeon, understanding the causes and treatment strategies for subjective complaints will determine a logical approach to each patient and create the potential to offer a worthwhile treatment. Ultimately, an understanding of the causes of dysphotopsias may allow for IOL designs that lead to improved performance and greater patient satisfaction. &
CAUSES/THEORIES FOR POSITIVE DYSPHOTOPSIAS Most, commonly elicited by a point source of light, positive pseudophakic dysphotopsias are presumed to be caused by stray light projected onto the retina. Given the diversity of symptoms, it is not surprising 46
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that the cause of positive dysphotopsias is likely multifactorial. Even though symptoms are common if elicited, the rarity of seriously disabling symptoms has led to a dearth of cause controlled studies. However, certain IOL characteristics are likely contributory. Acrylic square-edged IOLs, designed to decrease the formation of posterior capsular opacity, have been demonstrated by nonsequential ray tracing to concentrate stray light into a well formed arc on the retina opposite the image of the glare source [7], which may be perceived as a thin crescent or partial ring in the periphery. In the same model, round-edged IOLs tended to disperse stray light over a larger portion of the retina, reducing the intensity of the reflected glare image. Other authors likewise performed ray tracing using an experimental eye model and demonstrated similar findings, and they suggest that an IOL with a rounded anterior edge and a sharp posterior edge may be beneficial [8]. In a subsequent article [9], the same authors reported that frosting the edge of a square-edged IOL reduced the intensity of the ghost image, but increased the amount of stray light. In a prospective, double-masked clinical study [10], texturing the square-edge of an IOL led to significantly reduced positive dysphotopsias. Another ray-tracing model suggested a critical oblique nasal angle for the effects to be produced [11]. Clinical experience supports that square-edged IOLs are associated with positive dysphotopsias [1,2,12–15]. Other authors have suggested that high refractive index IOLs may also contribute to positive dysphotopsias, as light reflected off the retina onto the posterior surface of the IOL may subsequently be partially reflected back to the retina [16]. Alternatively, reflection of light from the retina may occur at each face of the IOL (i.e., posterior then anterior surface) before being transmitted back to the retina [14]. Additional optical eye modeling demonstrated that an unequal biconvex IOL design composed of a higher refractive index material increased the potential for glare and reflections [16]. The same group subsequently demonstrated that although all IOLs increased the intensity of reflections compared with the crystalline lens, surface reflections were minimized if the IOL anterior radius of curvature was 17.0 mm or less [17].
MANAGEMENT STRATEGIES FOR POSITIVE DYSPHOTOPSIAS Most patients with positive dysphotopsias are able to tolerate their symptoms without specific management. For those who have persistent and intolerable symptoms, IOL exchange has been described with some success. Davison [2] performed IOL exchange Volume 26 Number 1 January 2015
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Subjective complaints after cataract surgery Hood and Sugar
in five eyes with acrylic IOLs, placing poly(methyl methacrylate) (PMMA) or silicone IOLs in the capsular bag with the resolution of symptoms. Farbowitz et al. [14] similarly exchanged PMMA or silicone IOLs for acrylic IOLs in nine eyes with alleviation of most symptoms. In another report, three eyes had complete resolution of glare symptoms with exchange of the existing IOL for a PMMA IOL in the sulcus or capsular bag [13]. A multipiece silicone IOL piggybacked into the sulcus led to the resolution of symptoms in a single patient report [18]. Future studies should seek to further define the IOL characteristics that may increase the likelihood of positive dysphotopsias, as well as the identification of any contributing patient factors. This could allow clinicians to avoid certain IOL designs in predisposed patients, but ultimately the goal would be the development of novel IOL designs that incorporate optical principles to eliminate dysphotopsias.
CAUSES/THEORIES FOR NEGATIVE DYSPHOTOPSIAS The most common subjective description of negative dysphotopsias is a dark shadow in the temporal visual field. Although initially reported in eyes with a high refractive index square-edged acrylic IOL [2], they have now been reported with many IOL materials and designs [19–21]. Although changes in edge design have reduced the occurrence of positive dysphotopsias, negative dysphotopsias continue to remain a potential problem. The causes underlying longer term negative dysphotopsias remained more elusive than for positive dysphotopsias. Osher [22] has postulated that transient negative dysphotopsias, which occur shortly after cataract surgery and resolve within a few weeks, may be associated with the edema of temporal clear corneal incisions. Although no symptoms were severe enough to warrant an IOL exchange, the author reported an incidence of 15.2% on the first postoperative day, which decreased to 2.4% after 2 years. Many mechanisms underlying long-term negative dysphotopsias have been suggested, including truncated optic edges [19,23], high index of refraction optic materials [2,23], transparency of the peripheral nasal capsule [22,23], and a reflection of the anterior capsulotomy edge [24]. However, the most unifying theory was proposed by Holladay et al. [23] using an optical design program. They demonstrated that there are primary and secondary optical factors necessary to produce negative dysphotopsias when light rays passing through the peripheral edge of the IOL
are refracted posterior to those passing through the posterior surface, creating a shadow between them. Importantly, their theory explains most, if not all, reported clinical observations. Primary ocular factors required for symptoms were a small pupil, a distance behind the pupil of 0.06–1.23 mm for acrylic, sharp-edged IOLs, and a functional nasal retina that extends anterior to the shadow. Secondary factors included an IOL with a high index of refraction, angle a (the angle between the visual axis and the optical axis of the eye) and a nasal location of the pupil relative to the eye’s optical axis.
MANAGEMENT STRATEGIES FOR NEGATIVE DYSPHOTOPSIAS The incidence of IOL exchange for patients with negative dysphotopsias has been reported to be 0.13% [25]. For those patients who are significantly bothered by negative dysphotopsias, several successful treatment strategies have been reported, including ciliary sulcus placement of the IOL, secondary placement of a piggyback IOL in the sulcus, reverse optic capture of the IOL optic, and Nd:YAG (neodymium-doped yttrium aluminium garnet) laser anterior capsulotomy. Theoretical results from Holladay et al. [23,26] predict that the only definitive way to eliminate negative dysphotopsias is to exchange the posterior chamber IOL for an anterior chamber IOL, or for an IOL with fully rounded edges. Exchanges for silicone material, secondary piggyback IOLs, and reverse optic capture would be expected to improve symptoms but cannot guarantee elimination [26]. In accordance with these predictions, authors have reported the persistence of symptoms when an IOL exchange was performed with implantation into the reopened capsular bag, but elimination when an IOL exchange was performed with placement in the ciliary sulcus [25]. Masket and Fram [24] report that a piggyback IOL or reverse optic capture partially or completely eliminated symptoms in 10 patients; they also report lack of improvement in patients who had in-the-bag IOL exchange (n ¼ 3) or iris suture fixation of the capsular bag–IOL complex (n ¼ 1). Another case report documents elimination of negative dysphotopsias with the insertion of a toric piggyback IOL into the sulcus [27]. Weinstein [28], in his experience of 21 IOL explanations for negative dysphotopsias, reported improvement in symptoms in all patients when placing a round-edge silicone IOL in the capsular bag or sulcus, with complete resolution of symptoms in 86%. More recently, Burke and Benjamin [29 ] reported resolution of symptoms in five patients who underwent IOL exchange with
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Cataract surgery and lens implantation
the placement of a three-piece IOL in the sulcus. Additionally, a patient, who underwent cataract surgery with negative dysphotopsia symptoms in her fellow eye, did not develop them after primary placement of a sulcus IOL in the operative eye. Lastly, Nd:YAG laser anterior capsulotomy may avoid intraocular surgical manipulation in some patients with bothersome symptoms. Folden [30 ] reported six cases in which Nd:YAG removal of a nasal sector of the anterior capsule overlying the optic resolved symptoms completely in three eyes and partially in two others; symptoms did not improve in another eye with a different IOL design. Other authors reported resolution of symptoms in a single eye treated similarly [31]. As predicted by Holladay et al. [23,26], opacification of the anterior capsule overlying the IOL optic contributes to the mechanism of negative dysphotopsias in some patients, as it scatters light and creates a new path for incident light to reach the sharp posterior edge of the optic. &
MULTIFOCAL INTRAOCULAR LENS IMPLANTS Refractive and diffractive multifocal IOLs offer patients the possibility of improved near vision and reduced spectacle dependence by simultaneously presenting multiple images on the retina by having two or more fixed adapting focal points rather than one [32]. A recent Cochrane review supported the fact that patients with multifocal IOLs should expect to obtain similar distance vision to patients with monofocal IOLs, while also having less reliance on spectacles for near vision [33]. However, patients did have reduced contrast sensitivity and a higher incidence of glare and halos [33]. Given the complex optical surfaces of multifocal IOLs, it is not surprising that optical aberrations secondary to intraocular stray light are more common compared to monofocal IOLs. In a retrospective analysis of 2600 eyes that underwent diffractive multifocal IOL implantation, severe glare and halos were reported in 6.1 and 2.1% of patients, respectively [34]. In a prospective, randomized clinical trial of multifocal versus monovision monofocal IOLs, six patients (5.7%) in the multifocal arm underwent IOL exchange for visual symptoms, whereas none in the monovision arm did [35 ]. Another recent prospective randomized study [36] compared monovision with multifocal IOL implantation in 75 patients. Multifocal IOL insertion was associated with less dependence on spectacles overall but significantly more dysphotopsias. Another study [37] on 43 patients similarly demonstrated more disturbing visual symptoms in patients who underwent &
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multifocal IOL implantation compared with those who had pseudophakic monovision. In a retrospective series of 9366 eyes implanted with a multifocal IOL, severe dysphotopsias necessitated an IOL exchange in 0.6% of eyes [38].
MANAGEMENT STRATEGIES Ametropia and astigmatism, posterior capsular opacification, dry eye syndrome, large pupil size, IOL decentration, and retained lens fragment should be considered when evaluating patients with blurred vision or dysphotopsias after multifocal IOL implantation [39–41]. For patients with these symptoms, conservative management has been described to improve symptoms in up to 81%, with 7% of patients requiring an IOL exchange [40]. In another series of patients with visual complaints after multifocal IOL implantation, IOL exchange was performed in 4% of cases, with the majority of complaints (84%) amenable to other therapeutic options, such as refractive surgery, spectacles, or laser posterior capsulotomy [41]. A recent retrospective series of 50 eyes demonstrated that IOL exchange appears to be a feasible option for dissatisfied patients with persistent visual symptoms secondary to multifocal IOLs [42 ]. Patient satisfaction improved significantly from 1.22 0.55 to 3.78 0.97 on a 1 (very dissatisfied) to 5 (very satisfied) scale. &
CONCLUSION Although modern cataract surgery is extremely successful, dysphotopsias after implantation of monofocal IOLs occur and can rarely be disabling to patients. Subjective visual complaints after implantation of multifocal IOLs are more common, but still rarely require a significant intervention. Clinical observations and theoretical studies have better elucidated the mechanisms behind both negative and positive dysphotopsias. After characterizing patients’ symptoms, clinicians can consider treatment strategies that will most likely be successful. Ultimately, a better understanding of the risk factors and optical causes of dysphotopsias will allow for optimized IOL designs and patient selection that will lead to the elimination of subjective complaints after cataract surgery. Acknowledgements None. Conflicts of interest There are no conflicts of interest. Volume 26 Number 1 January 2015
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Subjective complaints after cataract surgery Hood and Sugar
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. Tester R, Pace NL, Samore M, et al. Dysphotopsia in phakic and pseudophakic patients: incidence and relation to intraocular lens type(2). J Cataract Refract Surg 2000; 26:810–816. 2. Davison JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg 2000; 26:1346–1355. 3. Aslam TM, Gupta M, Gilmour D, et al. Long-term prevalence of pseudophakic photic phenomena. Am J Ophthalmol 2007; 143:522–524. 4. Shambhu S, Shanmuganathan VA, Charles SJ. The effect of lens design on dysphotopsia in different acrylic IOLs. Eye (Lond) 2005; 19:567–570. 5. Kinard K, Jarstad A, Olson RJ. Correlation of visual quality with satisfaction & and function in a normal cohort of pseudophakic patients. J Cataract Refract Surg 2013; 39:590–597. In this retrospective study of 70 patients after uncomplicated cataract surgery with good corrected visual acuity, dysphotopsias were negatively correlated with overall satisfaction. Dysphotopsia symptoms were also highly correlated with the National Eye Institute Visual Function Questionnaire, indicating symptoms have functional significance. 6. Welch NR, Gregori N, Zabriskie N, et al. Satisfaction and dysphotopsia in the pseudophakic patient. Can J Ophthalmol 2010; 45:140–143. 7. Holladay JT, Lang A, Portney V. Analysis of edge glare phenomena in intraocular lens edge designs. J Cataract Refract Surg 1999; 25:748–752. 8. Franchini A, Gallarati BZ, Vaccari E. Computerized analysis of the effects of intraocular lens edge design on the quality of vision in pseudophakic patients. J Cataract Refract Surg 2003; 29:342–347. 9. Franchini A, Gallarati BZ, Vaccari E. Analysis of stray-light effects related to intraocular lens edge design. J Cataract Refract Surg 2004; 30:1531–1536. 10. Meacock WR, Spalton DJ, Khan S. The effect of texturing the intraocular lens edge on postoperative glare symptoms: a randomized, prospective, doublemasked study. Arch Ophthalmol 2002; 120:1294–1298. 11. Coroneo MT, Pham T, Kwok LS. Off-axis edge glare in pseudophakic dysphotopsia. J Cataract Refract Surg 2003; 29:1969–1973. 12. Bournas P, Drazinos S, Kanellas D, et al. Dysphotopsia after cataract surgery: comparison of four different intraocular lenses. Ophthalmologica 2007; 221:378–383. 13. Ellis MF. Sharp-edged intraocular lens design as a cause of permanent glare. J Cataract Refract Surg 2001; 27:1061–1064. 14. Farbowitz MA, Zabriskie NA, Crandall AS, et al. Visual complaints associated with the AcrySof acrylic intraocular lens(1). J Cataract Refract Surg 2000; 26:1339–1345. 15. Masket S. Truncated edge design dysphotopsia and inhibition of posterior capsule opacification. J Cataract Refract Surg 2000; 26:145–147. 16. Erie JC, Bandhauer MH, McLaren JW. Analysis of postoperative glare and intraocular lens design. J Cataract Refract Surg 2001; 27:614–621. 17. Erie JC, Bandhauer MH. Intraocular lens surfaces and their relationship to postoperative glare. J Cataract Refract Surg 2003; 29:336–341. 18. Ernest PH. Severe photic phenomenon. J Cataract Refract Surg 2006; 32:685–686. 19. Narvaez J, Banning CS, Stulting RD. Negative dysphotopsia associated with implantation of the Z9000 intraocular lens. J Cataract Refract Surg 2005; 31:846–847. 20. Schwiegerling J. Recent developments in pseudophakic dysphotopsia. Curr Opin Ophthalmol 2006; 17:27–30. 21. Trattler WB, Whitsett JC, Simone PA. Negative dysphotopsia after intraocular lens implantation irrespective of design and material. J Cataract Refract Surg 2005; 31:841–845. 22. Osher RH. Negative dysphotopsia: long-term study and possible explanation for transient symptoms. J Cataract Refract Surg 2008; 34:1699–1707.
23. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: the enigmatic penumbra. J Cataract Refract Surg 2012; 38:1251–1265. 24. Masket S, Fram NR. Pseudophakic negative dysphotopsia: surgical management and new theory of etiology. J Cataract Refract Surg 2011; 37:1199– 1207. 25. Vamosi P, Csakany B, Nemeth J. Intraocular lens exchange in patients with negative dysphotopsia symptoms. J Cataract Refract Surg 2010; 36:418– 424. 26. Holladay JT. Reply: etiology of negative dysphotopsia. J Cataract Refract Surg 2013; 39:486.e1–486.e4. 27. Zeldovich A. Treatment of negative dysphotopsia with unique sulcus lens. Clin Experiment Ophthalmol 2012; 40:829–830. 28. Weinstein A. Surgical experience with pseudophakic negative dysphotopsia. J Cataract Refract Surg 2012; 38:561. 29. Burke TR, Benjamin L. Sulcus-fixated intraocular lens implantation for the & management of negative dysphotopsia. J Cataract Refract Surg 2014; 40:1469–1472. The authors report a series of five cases in which IOL exchange and replacement with a three-piece IOL in the ciliary sulcus was a well tolerated and effective treatment for the treatment of negative dysphotopsias. 30. Folden DV. Neodymium:YAG laser anterior capsulectomy: surgical option in & the management of negative dysphotopsia. J Cataract Refract Surg 2013; 39:1110–1115. In this series of six cases, the author reports that Nd:YAG laser anterior capsulotomy achieved limited success in treating negative dysphotopsias. 31. Cooke DL, Kasko S, Platt LO. Resolution of negative dysphotopsia after laser anterior capsulotomy. J Cataract Refract Surg 2013; 39:1107–1109. 32. De Vries NE, Nuijts RM. Multifocal intraocular lenses in cataract surgery: literature review of benefits and side effects. J Cataract Refract Surg 2013; 39:268–278. 33. Calladine D, Evans JR, Shah S, et al. Multifocal versus monofocal intraocular lenses after cataract extraction. Cochrane Database Syst Rev 2012; 9:CD003169. 34. Akaishi L, Vaz R, Vilella G, et al. Visual performance of Tecnis ZM900 diffractive multifocal IOL after 2500 implants: A 3-year followup. J Ophthalmol 2010; 2010. pii: 717591. doi: 10.1155/2010/717591. 35. Wilkins MR, Allan BD, Rubin GS, et al. Randomized trial of multifocal & intraocular lenses versus monovision after bilateral cataract surgery. Ophthalmology 2013; 120:2449–2455. In this multicenter trial of 212 patients, the authors report that patients randomized to bilateral implantation of a multifocal IOL were more likely to report being spectacle-independent but also more likely to undergo IOL exchange than those randomized to receive monofocal implants with the powers adjusted to give low monovision. 36. Labiris G, Giarmoukakis A, Patsiamanidi M, et al. Mini-monovision versus multifocal intraocular lens implantation. J Cataract Refract Surg 2014. [Epub ahead of print] 37. Zhang F, Sugar A, Jacobsen G, et al. Visual function and patient satisfaction: comparison between bilateral diffractive multifocal intraocular lenses and monovision pseudophakia. J Cataract Refract Surg 2011; 37:446–453. 38. Venter JA, Pelouskova M, Collins BM, et al. Visual outcomes and patient satisfaction in 9366 eyes using a refractive segmented multifocal intraocular lens. J Cataract Refract Surg 2013; 39:1477–1484. 39. Liu JW, Haw WW. Optimizing outcomes of multifocal intraocular lenses. Curr Opin Ophthalmol 2014; 25:44–48. 40. Woodward MA, Randleman JB, Stulting RD. Dissatisfaction after multifocal intraocular lens implantation. J Cataract Refract Surg 2009; 35:992–997. 41. De Vries NE, Webers CA, Touwslager WR, et al. Dissatisfaction after implantation of multifocal intraocular lenses. J Cataract Refract Surg 2011; 37:859–865. 42. Kamiya K, Hayashi K, Shimizu K, et al. Multifocal intraocular lens explantation: & a case series of 50 eyes. Am J Ophthalmol 2014; 158:215–220. The authors assess the visual complaints and satisfaction after multifocal IOL explantation in this series of 50 eyes. They report that IOL exchange surgery is a feasible option for dissatisfied patients after multifocal IOL implantation.
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Subjective complaints after cataract surgery: common causes and management strategies Christopher T. Hood and Alan Sugar
Purpose of review To describe the common causes of, and management strategies for, nonrefractive subjective visual complaints after cataract surgery. Recent findings Over the past decade, clinical observations and ray-tracing models have greatly increased our understanding of positive and negative dysphotopsias after cataract surgery. The primary factor behind positive dysphotopsias is the use of high refractive index square-edge intraocular lenses (IOLs). Primary and secondary factors that underlie negative dysphotopsias are now better characterized, which has led to successful interventions including IOL exchange and Nd:YAG laser anterior capsulotomy. Summary Positive and negative dysphotopsias occur after implantation of monofocal IOLs, and can rarely be disabling to patients. Visual complaints after multifocal IOL implantation are more common than after monofocal IOL implantation, but still rarely require significant intervention. A better understanding of the risk factors and optical causes of dysphotopsias will allow for IOL design and patient selection that maximize satisfaction after cataract surgery. Keywords cataract surgery, intraocular lenses exchange, negative dysphotopsia, positive dysphotopsia, subjective complaints
INTRODUCTION
BACKGROUND
Modern cataract surgery is the most commonly performed surgery in the USA and worldwide, and has an extremely high success rate in improving vision and quality of life. In a small fraction of patients, however, optical effects thought to be due to the implantation of intraocular lenses (IOL) lead to subjective visual complaints, including glare, halos, streaks, starbursts, shadows, and haze. Although these side-effects are usually readily tolerable to most patients, they are rarely more disabling than the preoperative state and, therefore, warrant management. This review will summarize the potential causes, and management strategies for, subjective complaints after cataract surgery, focusing on recent publications. Uncorrected refractive error and posterior capsular opacity, the two most common causes of visual disturbance after routine cataract surgery, will not be addressed. Visual complaints after multifocal IOL implantation will be discussed, but the focus will be on dysphotopsias in the setting of routine cataract surgery with monofocal IOL implants.
The term dysphotopsia was first used by Tester et al. [1] to describe a variety of undesired visual phenomena in both phakic and pseudophakic patients. Since their initial description, the terms positive and negative pseudophakic dysphotopsia have gained acceptance among clinicians. Positive dysphotopsias are defined as bright artifacts and include symptoms of arcs, streaks, rings, and halos. Negative dysphotopsias are perceived as shadows or dark areas, usually in the temporal visual field. Rarely, both types can be present simultaneously [2]. Both phenomena are thought to result from unwanted patterns superimposed on the retina, and may only be present under certain lighting Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA Correspondence to Alan Sugar, University of Michigan Kellogg Eye Center, 1000 Wall St., Ann Arbor, MI 48105, USA. Tel: +1 734 763 5506; fax: +1 734 936 2340; e-mail: [email protected] Curr Opin Ophthalmol 2015, 26:45–49 DOI:10.1097/ICU.0000000000000112
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Cataract surgery and lens implantation
KEY POINTS Although modern cataract surgery is extremely successful, dysphotopsias after implantation of IOLs occur and can rarely be disabling to patients and require intervention. Subjective visual complaints are more common after implantation of multifocal IOLs compared with monofocal IOLs. Optical modeling and clinical observations have better elucidated the mechanisms underlying both positive and negative dysphotopsias after implantation of monofocal IOLs. Surgical intervention, including IOL exchange, piggyback IOLs, and Nd:YAG laser anterior capsulotomy, may be successful in reducing or eliminating dysphotopsias. A better understanding of the risk factors and optical causes of dysphotopsias will allow for optimized IOL designs and patient selection that may eliminate subjective complaints after cataract surgery.
conditions or for certain locations of light sources (for example, a source in peripheral visual field). The overall incidence of pseudophakic dysphotopsias identified by unsolicited voiced complaints has been reported to be relatively rare [2], but given the prevalence of cataract surgery, these patients will be encountered in the routine practice of most cataract surgeons. Other authors have demonstrated that, if specifically questioned about symptoms, pseudophakic dysphotopsias may in fact be much more common, with an incidence of 33–78% [1,3,4]. Importantly for the clinician, symptoms of dysphotopsia were found to be negatively correlated with satisfaction and visual function in patients who underwent uneventful cataract surgery with good corrected visual acuity [5 ,6]. For the cataract surgeon, understanding the causes and treatment strategies for subjective complaints will determine a logical approach to each patient and create the potential to offer a worthwhile treatment. Ultimately, an understanding of the causes of dysphotopsias may allow for IOL designs that lead to improved performance and greater patient satisfaction. &
CAUSES/THEORIES FOR POSITIVE DYSPHOTOPSIAS Most, commonly elicited by a point source of light, positive pseudophakic dysphotopsias are presumed to be caused by stray light projected onto the retina. Given the diversity of symptoms, it is not surprising 46
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that the cause of positive dysphotopsias is likely multifactorial. Even though symptoms are common if elicited, the rarity of seriously disabling symptoms has led to a dearth of cause controlled studies. However, certain IOL characteristics are likely contributory. Acrylic square-edged IOLs, designed to decrease the formation of posterior capsular opacity, have been demonstrated by nonsequential ray tracing to concentrate stray light into a well formed arc on the retina opposite the image of the glare source [7], which may be perceived as a thin crescent or partial ring in the periphery. In the same model, round-edged IOLs tended to disperse stray light over a larger portion of the retina, reducing the intensity of the reflected glare image. Other authors likewise performed ray tracing using an experimental eye model and demonstrated similar findings, and they suggest that an IOL with a rounded anterior edge and a sharp posterior edge may be beneficial [8]. In a subsequent article [9], the same authors reported that frosting the edge of a square-edged IOL reduced the intensity of the ghost image, but increased the amount of stray light. In a prospective, double-masked clinical study [10], texturing the square-edge of an IOL led to significantly reduced positive dysphotopsias. Another ray-tracing model suggested a critical oblique nasal angle for the effects to be produced [11]. Clinical experience supports that square-edged IOLs are associated with positive dysphotopsias [1,2,12–15]. Other authors have suggested that high refractive index IOLs may also contribute to positive dysphotopsias, as light reflected off the retina onto the posterior surface of the IOL may subsequently be partially reflected back to the retina [16]. Alternatively, reflection of light from the retina may occur at each face of the IOL (i.e., posterior then anterior surface) before being transmitted back to the retina [14]. Additional optical eye modeling demonstrated that an unequal biconvex IOL design composed of a higher refractive index material increased the potential for glare and reflections [16]. The same group subsequently demonstrated that although all IOLs increased the intensity of reflections compared with the crystalline lens, surface reflections were minimized if the IOL anterior radius of curvature was 17.0 mm or less [17].
MANAGEMENT STRATEGIES FOR POSITIVE DYSPHOTOPSIAS Most patients with positive dysphotopsias are able to tolerate their symptoms without specific management. For those who have persistent and intolerable symptoms, IOL exchange has been described with some success. Davison [2] performed IOL exchange Volume 26 Number 1 January 2015
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Subjective complaints after cataract surgery Hood and Sugar
in five eyes with acrylic IOLs, placing poly(methyl methacrylate) (PMMA) or silicone IOLs in the capsular bag with the resolution of symptoms. Farbowitz et al. [14] similarly exchanged PMMA or silicone IOLs for acrylic IOLs in nine eyes with alleviation of most symptoms. In another report, three eyes had complete resolution of glare symptoms with exchange of the existing IOL for a PMMA IOL in the sulcus or capsular bag [13]. A multipiece silicone IOL piggybacked into the sulcus led to the resolution of symptoms in a single patient report [18]. Future studies should seek to further define the IOL characteristics that may increase the likelihood of positive dysphotopsias, as well as the identification of any contributing patient factors. This could allow clinicians to avoid certain IOL designs in predisposed patients, but ultimately the goal would be the development of novel IOL designs that incorporate optical principles to eliminate dysphotopsias.
CAUSES/THEORIES FOR NEGATIVE DYSPHOTOPSIAS The most common subjective description of negative dysphotopsias is a dark shadow in the temporal visual field. Although initially reported in eyes with a high refractive index square-edged acrylic IOL [2], they have now been reported with many IOL materials and designs [19–21]. Although changes in edge design have reduced the occurrence of positive dysphotopsias, negative dysphotopsias continue to remain a potential problem. The causes underlying longer term negative dysphotopsias remained more elusive than for positive dysphotopsias. Osher [22] has postulated that transient negative dysphotopsias, which occur shortly after cataract surgery and resolve within a few weeks, may be associated with the edema of temporal clear corneal incisions. Although no symptoms were severe enough to warrant an IOL exchange, the author reported an incidence of 15.2% on the first postoperative day, which decreased to 2.4% after 2 years. Many mechanisms underlying long-term negative dysphotopsias have been suggested, including truncated optic edges [19,23], high index of refraction optic materials [2,23], transparency of the peripheral nasal capsule [22,23], and a reflection of the anterior capsulotomy edge [24]. However, the most unifying theory was proposed by Holladay et al. [23] using an optical design program. They demonstrated that there are primary and secondary optical factors necessary to produce negative dysphotopsias when light rays passing through the peripheral edge of the IOL
are refracted posterior to those passing through the posterior surface, creating a shadow between them. Importantly, their theory explains most, if not all, reported clinical observations. Primary ocular factors required for symptoms were a small pupil, a distance behind the pupil of 0.06–1.23 mm for acrylic, sharp-edged IOLs, and a functional nasal retina that extends anterior to the shadow. Secondary factors included an IOL with a high index of refraction, angle a (the angle between the visual axis and the optical axis of the eye) and a nasal location of the pupil relative to the eye’s optical axis.
MANAGEMENT STRATEGIES FOR NEGATIVE DYSPHOTOPSIAS The incidence of IOL exchange for patients with negative dysphotopsias has been reported to be 0.13% [25]. For those patients who are significantly bothered by negative dysphotopsias, several successful treatment strategies have been reported, including ciliary sulcus placement of the IOL, secondary placement of a piggyback IOL in the sulcus, reverse optic capture of the IOL optic, and Nd:YAG (neodymium-doped yttrium aluminium garnet) laser anterior capsulotomy. Theoretical results from Holladay et al. [23,26] predict that the only definitive way to eliminate negative dysphotopsias is to exchange the posterior chamber IOL for an anterior chamber IOL, or for an IOL with fully rounded edges. Exchanges for silicone material, secondary piggyback IOLs, and reverse optic capture would be expected to improve symptoms but cannot guarantee elimination [26]. In accordance with these predictions, authors have reported the persistence of symptoms when an IOL exchange was performed with implantation into the reopened capsular bag, but elimination when an IOL exchange was performed with placement in the ciliary sulcus [25]. Masket and Fram [24] report that a piggyback IOL or reverse optic capture partially or completely eliminated symptoms in 10 patients; they also report lack of improvement in patients who had in-the-bag IOL exchange (n ¼ 3) or iris suture fixation of the capsular bag–IOL complex (n ¼ 1). Another case report documents elimination of negative dysphotopsias with the insertion of a toric piggyback IOL into the sulcus [27]. Weinstein [28], in his experience of 21 IOL explanations for negative dysphotopsias, reported improvement in symptoms in all patients when placing a round-edge silicone IOL in the capsular bag or sulcus, with complete resolution of symptoms in 86%. More recently, Burke and Benjamin [29 ] reported resolution of symptoms in five patients who underwent IOL exchange with
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Cataract surgery and lens implantation
the placement of a three-piece IOL in the sulcus. Additionally, a patient, who underwent cataract surgery with negative dysphotopsia symptoms in her fellow eye, did not develop them after primary placement of a sulcus IOL in the operative eye. Lastly, Nd:YAG laser anterior capsulotomy may avoid intraocular surgical manipulation in some patients with bothersome symptoms. Folden [30 ] reported six cases in which Nd:YAG removal of a nasal sector of the anterior capsule overlying the optic resolved symptoms completely in three eyes and partially in two others; symptoms did not improve in another eye with a different IOL design. Other authors reported resolution of symptoms in a single eye treated similarly [31]. As predicted by Holladay et al. [23,26], opacification of the anterior capsule overlying the IOL optic contributes to the mechanism of negative dysphotopsias in some patients, as it scatters light and creates a new path for incident light to reach the sharp posterior edge of the optic. &
MULTIFOCAL INTRAOCULAR LENS IMPLANTS Refractive and diffractive multifocal IOLs offer patients the possibility of improved near vision and reduced spectacle dependence by simultaneously presenting multiple images on the retina by having two or more fixed adapting focal points rather than one [32]. A recent Cochrane review supported the fact that patients with multifocal IOLs should expect to obtain similar distance vision to patients with monofocal IOLs, while also having less reliance on spectacles for near vision [33]. However, patients did have reduced contrast sensitivity and a higher incidence of glare and halos [33]. Given the complex optical surfaces of multifocal IOLs, it is not surprising that optical aberrations secondary to intraocular stray light are more common compared to monofocal IOLs. In a retrospective analysis of 2600 eyes that underwent diffractive multifocal IOL implantation, severe glare and halos were reported in 6.1 and 2.1% of patients, respectively [34]. In a prospective, randomized clinical trial of multifocal versus monovision monofocal IOLs, six patients (5.7%) in the multifocal arm underwent IOL exchange for visual symptoms, whereas none in the monovision arm did [35 ]. Another recent prospective randomized study [36] compared monovision with multifocal IOL implantation in 75 patients. Multifocal IOL insertion was associated with less dependence on spectacles overall but significantly more dysphotopsias. Another study [37] on 43 patients similarly demonstrated more disturbing visual symptoms in patients who underwent &
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multifocal IOL implantation compared with those who had pseudophakic monovision. In a retrospective series of 9366 eyes implanted with a multifocal IOL, severe dysphotopsias necessitated an IOL exchange in 0.6% of eyes [38].
MANAGEMENT STRATEGIES Ametropia and astigmatism, posterior capsular opacification, dry eye syndrome, large pupil size, IOL decentration, and retained lens fragment should be considered when evaluating patients with blurred vision or dysphotopsias after multifocal IOL implantation [39–41]. For patients with these symptoms, conservative management has been described to improve symptoms in up to 81%, with 7% of patients requiring an IOL exchange [40]. In another series of patients with visual complaints after multifocal IOL implantation, IOL exchange was performed in 4% of cases, with the majority of complaints (84%) amenable to other therapeutic options, such as refractive surgery, spectacles, or laser posterior capsulotomy [41]. A recent retrospective series of 50 eyes demonstrated that IOL exchange appears to be a feasible option for dissatisfied patients with persistent visual symptoms secondary to multifocal IOLs [42 ]. Patient satisfaction improved significantly from 1.22 0.55 to 3.78 0.97 on a 1 (very dissatisfied) to 5 (very satisfied) scale. &
CONCLUSION Although modern cataract surgery is extremely successful, dysphotopsias after implantation of monofocal IOLs occur and can rarely be disabling to patients. Subjective visual complaints after implantation of multifocal IOLs are more common, but still rarely require a significant intervention. Clinical observations and theoretical studies have better elucidated the mechanisms behind both negative and positive dysphotopsias. After characterizing patients’ symptoms, clinicians can consider treatment strategies that will most likely be successful. Ultimately, a better understanding of the risk factors and optical causes of dysphotopsias will allow for optimized IOL designs and patient selection that will lead to the elimination of subjective complaints after cataract surgery. Acknowledgements None. Conflicts of interest There are no conflicts of interest. Volume 26 Number 1 January 2015
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Subjective complaints after cataract surgery Hood and Sugar
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. Tester R, Pace NL, Samore M, et al. Dysphotopsia in phakic and pseudophakic patients: incidence and relation to intraocular lens type(2). J Cataract Refract Surg 2000; 26:810–816. 2. Davison JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg 2000; 26:1346–1355. 3. Aslam TM, Gupta M, Gilmour D, et al. Long-term prevalence of pseudophakic photic phenomena. Am J Ophthalmol 2007; 143:522–524. 4. Shambhu S, Shanmuganathan VA, Charles SJ. The effect of lens design on dysphotopsia in different acrylic IOLs. Eye (Lond) 2005; 19:567–570. 5. Kinard K, Jarstad A, Olson RJ. Correlation of visual quality with satisfaction & and function in a normal cohort of pseudophakic patients. J Cataract Refract Surg 2013; 39:590–597. In this retrospective study of 70 patients after uncomplicated cataract surgery with good corrected visual acuity, dysphotopsias were negatively correlated with overall satisfaction. Dysphotopsia symptoms were also highly correlated with the National Eye Institute Visual Function Questionnaire, indicating symptoms have functional significance. 6. Welch NR, Gregori N, Zabriskie N, et al. Satisfaction and dysphotopsia in the pseudophakic patient. Can J Ophthalmol 2010; 45:140–143. 7. Holladay JT, Lang A, Portney V. Analysis of edge glare phenomena in intraocular lens edge designs. J Cataract Refract Surg 1999; 25:748–752. 8. Franchini A, Gallarati BZ, Vaccari E. Computerized analysis of the effects of intraocular lens edge design on the quality of vision in pseudophakic patients. J Cataract Refract Surg 2003; 29:342–347. 9. Franchini A, Gallarati BZ, Vaccari E. Analysis of stray-light effects related to intraocular lens edge design. J Cataract Refract Surg 2004; 30:1531–1536. 10. Meacock WR, Spalton DJ, Khan S. The effect of texturing the intraocular lens edge on postoperative glare symptoms: a randomized, prospective, doublemasked study. Arch Ophthalmol 2002; 120:1294–1298. 11. Coroneo MT, Pham T, Kwok LS. Off-axis edge glare in pseudophakic dysphotopsia. J Cataract Refract Surg 2003; 29:1969–1973. 12. Bournas P, Drazinos S, Kanellas D, et al. Dysphotopsia after cataract surgery: comparison of four different intraocular lenses. Ophthalmologica 2007; 221:378–383. 13. Ellis MF. Sharp-edged intraocular lens design as a cause of permanent glare. J Cataract Refract Surg 2001; 27:1061–1064. 14. Farbowitz MA, Zabriskie NA, Crandall AS, et al. Visual complaints associated with the AcrySof acrylic intraocular lens(1). J Cataract Refract Surg 2000; 26:1339–1345. 15. Masket S. Truncated edge design dysphotopsia and inhibition of posterior capsule opacification. J Cataract Refract Surg 2000; 26:145–147. 16. Erie JC, Bandhauer MH, McLaren JW. Analysis of postoperative glare and intraocular lens design. J Cataract Refract Surg 2001; 27:614–621. 17. Erie JC, Bandhauer MH. Intraocular lens surfaces and their relationship to postoperative glare. J Cataract Refract Surg 2003; 29:336–341. 18. Ernest PH. Severe photic phenomenon. J Cataract Refract Surg 2006; 32:685–686. 19. Narvaez J, Banning CS, Stulting RD. Negative dysphotopsia associated with implantation of the Z9000 intraocular lens. J Cataract Refract Surg 2005; 31:846–847. 20. Schwiegerling J. Recent developments in pseudophakic dysphotopsia. Curr Opin Ophthalmol 2006; 17:27–30. 21. Trattler WB, Whitsett JC, Simone PA. Negative dysphotopsia after intraocular lens implantation irrespective of design and material. J Cataract Refract Surg 2005; 31:841–845. 22. Osher RH. Negative dysphotopsia: long-term study and possible explanation for transient symptoms. J Cataract Refract Surg 2008; 34:1699–1707.
23. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: the enigmatic penumbra. J Cataract Refract Surg 2012; 38:1251–1265. 24. Masket S, Fram NR. Pseudophakic negative dysphotopsia: surgical management and new theory of etiology. J Cataract Refract Surg 2011; 37:1199– 1207. 25. Vamosi P, Csakany B, Nemeth J. Intraocular lens exchange in patients with negative dysphotopsia symptoms. J Cataract Refract Surg 2010; 36:418– 424. 26. Holladay JT. Reply: etiology of negative dysphotopsia. J Cataract Refract Surg 2013; 39:486.e1–486.e4. 27. Zeldovich A. Treatment of negative dysphotopsia with unique sulcus lens. Clin Experiment Ophthalmol 2012; 40:829–830. 28. Weinstein A. Surgical experience with pseudophakic negative dysphotopsia. J Cataract Refract Surg 2012; 38:561. 29. Burke TR, Benjamin L. Sulcus-fixated intraocular lens implantation for the & management of negative dysphotopsia. J Cataract Refract Surg 2014; 40:1469–1472. The authors report a series of five cases in which IOL exchange and replacement with a three-piece IOL in the ciliary sulcus was a well tolerated and effective treatment for the treatment of negative dysphotopsias. 30. Folden DV. Neodymium:YAG laser anterior capsulectomy: surgical option in & the management of negative dysphotopsia. J Cataract Refract Surg 2013; 39:1110–1115. In this series of six cases, the author reports that Nd:YAG laser anterior capsulotomy achieved limited success in treating negative dysphotopsias. 31. Cooke DL, Kasko S, Platt LO. Resolution of negative dysphotopsia after laser anterior capsulotomy. J Cataract Refract Surg 2013; 39:1107–1109. 32. De Vries NE, Nuijts RM. Multifocal intraocular lenses in cataract surgery: literature review of benefits and side effects. J Cataract Refract Surg 2013; 39:268–278. 33. Calladine D, Evans JR, Shah S, et al. Multifocal versus monofocal intraocular lenses after cataract extraction. Cochrane Database Syst Rev 2012; 9:CD003169. 34. Akaishi L, Vaz R, Vilella G, et al. Visual performance of Tecnis ZM900 diffractive multifocal IOL after 2500 implants: A 3-year followup. J Ophthalmol 2010; 2010. pii: 717591. doi: 10.1155/2010/717591. 35. Wilkins MR, Allan BD, Rubin GS, et al. Randomized trial of multifocal & intraocular lenses versus monovision after bilateral cataract surgery. Ophthalmology 2013; 120:2449–2455. In this multicenter trial of 212 patients, the authors report that patients randomized to bilateral implantation of a multifocal IOL were more likely to report being spectacle-independent but also more likely to undergo IOL exchange than those randomized to receive monofocal implants with the powers adjusted to give low monovision. 36. Labiris G, Giarmoukakis A, Patsiamanidi M, et al. Mini-monovision versus multifocal intraocular lens implantation. J Cataract Refract Surg 2014. [Epub ahead of print] 37. Zhang F, Sugar A, Jacobsen G, et al. Visual function and patient satisfaction: comparison between bilateral diffractive multifocal intraocular lenses and monovision pseudophakia. J Cataract Refract Surg 2011; 37:446–453. 38. Venter JA, Pelouskova M, Collins BM, et al. Visual outcomes and patient satisfaction in 9366 eyes using a refractive segmented multifocal intraocular lens. J Cataract Refract Surg 2013; 39:1477–1484. 39. Liu JW, Haw WW. Optimizing outcomes of multifocal intraocular lenses. Curr Opin Ophthalmol 2014; 25:44–48. 40. Woodward MA, Randleman JB, Stulting RD. Dissatisfaction after multifocal intraocular lens implantation. J Cataract Refract Surg 2009; 35:992–997. 41. De Vries NE, Webers CA, Touwslager WR, et al. Dissatisfaction after implantation of multifocal intraocular lenses. J Cataract Refract Surg 2011; 37:859–865. 42. Kamiya K, Hayashi K, Shimizu K, et al. Multifocal intraocular lens explantation: & a case series of 50 eyes. Am J Ophthalmol 2014; 158:215–220. The authors assess the visual complaints and satisfaction after multifocal IOL explantation in this series of 50 eyes. They report that IOL exchange surgery is a feasible option for dissatisfied patients after multifocal IOL implantation.
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