The introduction of small incision cataract surgery with implantation of foldable intraocular lenses (IOLs) provided several benefits to patients.1–4 It also gave surgeons new choices in foldable IOLs of different materials. At present, foldable IOLs are available in silicone, acrylic, and hydrogel biomaterials. At our institution, silicone and acrylic foldable IOLs are the most frequently used.
The AMO SI-30 and SI-40 are silicone foldable IOLs with a 6.0 mm optic and differ only in haptic material: polypropylene and poly(methyl methacrylate), respectively. The Alcon MA30BA and MA60BA IOLs are both acrylic and are similar except in optic size: 5.5 mm and 6.0 mm, respectively.
Several patients at John Moran Eye Center have expressed strong dissatisfaction with the acrylic Alcon foldable IOLs, even with excellent objective Snellen visual acuity. Some have demanded that the IOL be explanted.5 The main complaints were not decreased visual acuity but bothersome to unacceptable glare symptoms.
Recent scanning electron microscopic analysis found that the optic edge of MA30BA and MA60BA IOLs is sharp and distinct compared with that of SI-30 and SI-40 IOLs.6 Although sharp optic edges have been reported to decrease the formation of posterior capsule opacification after IOL implantation, they have also been implicated in edge-glare symptoms.7
This paper reports our first survey of patient satisfaction with vision after uneventful small incision cataract surgery and implantation of an SI-30, SI-40, MA30BA, or MA60BA IOL. It predates our recently published study8 and is the foundation on which that study was based. Our goal was to determine the differences in patient satisfaction among the 3 IOL groups with regard to visual blurring symptoms, glare symptoms, night vision, near vision, and overall vision.
Patients and methods
In this study, 162 patients were divided into 3 groups of 54 based on IOL type: SI-30/40, MA30BA, and MA60BA. All patients had uneventful phacoemulsification with a temporal clear corneal incision or superior scleral tunnel incision, a curvilinear capsulorhexis, and in-the-bag IOL placement. The mean follow-up was approximately 15 months (range 12 to 18 months).
Patients were surveyed by telephone after providing consent. They were selected in a consecutive fashion starting with the first patient with a minimum of 12 months of follow-up. The interviewer was not masked to IOL type.
Each patient was interviewed for approximately 10 to 15 minutes. A standardized script was used to ask patients about their satisfaction with visual blurring symptoms, glare symptoms, night vision, near vision, and overall vision. The scale for patient satisfaction was from 1 to 4 as follows: 1= very unsatisfied; 2 = somewhat unsatisfied; 3 = generally satisfied; 4 = very satisfied. Care was taken to ensure that the patient understood the scale before answering the questions. The scale was repeated to the patient if there was uncertainty.
The data collected were analyzed using the analysis of variance method for comparison of continuous variables. Because the patients were not examined, the posterior capsule status could not be accurately assessed.
There were no significant differences among the 3 groups in visual blurring symptoms or night vision (Table 1). Patients in the SI-30/40 and the MA60BA groups expressed significantly higher satisfaction with glare symptoms, near vision, and overall satisfaction than patients in the MA30BA group (Table 1) (P < .0001).
We found that many patients had unwanted symptoms that affected their satisfaction. We previously reported that this dissatisfaction can be so strong that the patient is not happy until the IOL is removed and replaced with one that eliminates the problem.5 In regard to excellence in cataract surgery, unwanted images after surgery is a frontier we have not conquered.
From a purely theoretical basis, the smaller the IOL optic, the greater the likelihood that the edge will be visible and the less room for error in regard to IOL decentration. It is therefore not surprising that the 5.5 mm optic caused greater difficulty than the other 2 lens models with a 6.0 mm optic.
In our study of actual unwanted visual phenomenon versus general complaints,8 we found no difference between the 5.5 mm and 6.0 mm AcrySof IOLs. Both lenses led to specific complaints associated with central flashes of light at night, even when patients were not looking directly at the light. Holladay and coauthors7 found this to be a mirror effect resulting from the flattened IOL edge. In contrast, in the present study, there was no difference in patient-reported night vision among the IOL groups. Glare and near vision were the most common complaints. In our previous study,8 many patients said they had stopped driving at night, even after successful cataract surgery. Thus, it is probable that lifestyle during the evening and at night plays a major role in patient satisfaction. This same study documented that more patients with an SI-40 IOL drove at night than patients with the other IOLs.
Glare is a nonspecific complaint that we tried to evaluate more specifically in our previous study. We assume that our present patients were presenting their reaction to bright lights in front of them. Optic size had the biggest impact on the patients' responses and overall satisfaction with regard to glare. Masket et al.9 found that optic size, especially with oval IOLs, had a significant effect on patient satisfaction. Near vision complaints were probably of the same source; that is, bright light bouncing off white paper.
Outcomes study results are dependent on what questions are asked and how they prompt patient memory. Many of our patients said they had no problems until they were asked specific questions about symptoms. However, they said that their concerns were not significant in light of the overall improvement in vision after cataract surgery. Standardized outcomes studies should be conducted to obtain reproducible results because how the questions are asked can affect the patient's response.
One criticism of our study was that we did not assess the status of the posterior capsule. The capsulotomy rate for the silicone and acrylic IOLs we used has been shown to be low, especially in the 12 to 18 month time frame.10 Thus, we believe that the capsulotomy rate was below 10% in all 3 IOL groups and it did not likely have a significant effect on the results.
Patient satisfaction was significantly greater with the 2 6.0 mm IOLs than with the 5.5 mm AcrySof IOL. A review of explantation of 5.5 mm and 6.0 mm AcrySof IOLs found that the preponderance of explantations were of the 5.5 mm IOL for unwanted optical images (N. Mamalis, MD, “Survey on Foldable IOLs Requiring Explantation or Secondary Intervention: 1999 Update,” presented at the Symposium on Cataract, IOL and Refractive Surgery, Boston, Massachusetts, USA, May 2000). When patients were specifically asked about a visual phenomenon, the edge configuration was more important than optic size, as in our previous study. Visual complaints were often similar in incidence in a control group of normal eyes.8 Further study must be done to discern between normal night glare and unwanted images that are directly a result of the IOL.
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6. Omar O, Mamalis N, Veiga J, et al. Scanning electron microscopic characteristics of small-incision intraocular lenses. Ophthalmology 1996; 103:1124-1129
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9. Masket S, Geraghty E, Crandall AS, et al. Undesired light images associated with ovoid intraocular lenses. J Cataract Refract Surg 1993; 19:690-694
10. Hayashi H, Hayashi K, Nakao F, Hayashi F. Quantitative comparison of posterior capsule opacification after polymethylmethacrylate, silicone, and soft acrylic intraocular lens implantation. Arch Ophthalmol 1998; 116:1579-1582