- Email: [email protected]
Clinical evaluation of the Unfolder
Clinical evaluation of the Unfolder Randall Olson, MD, Robert Cameron, MD, Todd Hovis, MD, John Hunkeler, MD, Richard Lindstrom, MD, Roger Steinert, MD
ABSTRACT Purpose: To evaluate the clinical acceptability of the Unfolder™ for implantation of AMO® PhacoFlex II® (model SI-30NB or SI-40NB) intraocular lenses (IOLs). Setting: Six investigational sites in five states in the United States: Utah, Texas, Missouri, Minnesota, and Massachusetts. Methods: One hundred one patients from six investigational sites had implantation of an SI-30NB or SI-40NB IOL. Investigators evaluated the clinical acceptability of the Unfolder by comparing their experience with the injector with that using other implantation systems. Internal incision size (dimensions) was measured three times during surgery using a calibrated instrument. Data on safety and efficacy were collected. Results: The investigators rated the Unfolder as clinically acceptable. Mean internal incision size after phacoemulsification but before IOL implantation was 3.0 mm ± 0.1 (SO) (range 2.7 to 3.2 mm). Average internal incision size after IOL implantation was 3.1 ± 0.1 mm. There were no reports of haptic deformation, lens optic damage, or postoperative complications related to the Unfolder. No adverse events were reported. Conclusions: Investigators found the Unfolder easy to use. It provided controlled lens implantation through incisions 2.7 to 3.2 mm, with post-IOL implantation incisions ranging from 2.9 to 3.3 mm. J Cataract Refract Surg 1997; 23: 1384-1389
T
he benefits of small incision surgery are well documented and include rapid visual rehabilitation,I,2 reduced postoperative astigmatism,I,2 and decreased postoperative inflammation. I,3 One method of foldable intraocular lens (IOL) implantation that uses the benefits of small incisions is the lens injector.
Presented in part at the 1997 Royal Hawaiian Eye, Honolulu, Hawaii, USA, January 1997, and the Symposium on Cataract, IOL and Refractive Surgery, Boston, Massachusetts, USA, April 1997. Supported in part by Allergan and by a grant from Research to Prevent Blindness, Inc., New York, New York, USA, to the Department of Ophthalmology, University of Utah. Reprint requests to Randall Olson, MD, 50 North Medical Drive, Salt Lake City, Utah 84132, USA. 1384
The Unfolder™ (AMO® PhacoFlex II® SoITipTM insertion system, Allergan) is designed to implant AMO PhacoFlex II silicone monofocal IOL models SI-30NB and SI-40NB through incisions ranging in size from 2.7 to 3.2 mm. The Unfolder consists of a disposable cartridge with a central, sliding, reusable handpiece rod composed of titanium (Figure 1). The inserter has a soft silicone tip that is applied to the handpiece rod before use (Figure 2) to prevent direct contact between the titanium rod and silicone optic. It is designed to gently guide lenses through the lens cartridge, minimizing lens distortion and facilitating controlled lens release. The cartridge has an image of a lens etched into the surface of the wing (Figure 3). This image shows the
J CATARACT REFRACT SURG-VOL 23, NOVEMBER 1997
CLINICAL EVALUATION OF THE UNFOLDER
Figure 1. (Olson) Unfolder system components.
Figure 2. (Olson) Application of the soft tip on the handpiece rod.
proper lens placement before the cartridge is closed. The clear cartridge and the side-view window on the handpiece allow the surgeon to visualize the leading haptic and verify its correct position before the lens is injected into the eye. A bench-top, in vitro analysis of the Unfolder was performed to determine whether the device reliably delivers SI-30NB and SI-40NB lenses in a controlled manner without significantly affecting optical performance, lens dimensions, or cosmetic appearance. Seventytwo SI-30NB and SI-40NB IOLs with polypropylene and poly(methyl methacrylate) haptics, respectively, were used in the evaluation. Simulated lens insertion showed that there were minimal changes to the physical
and optical characteristics of IOLs (unpublished data, Allergan, 1996). The current study assessed the clinical acceptability of the Unfolder in the implantation of SI-30NB and SI-40NB IOLs.
Patients and Methods An open-label, noncomparative evaluation of the Unfolder was conducted by six investigators at six investigational sites. Each investigator implanted SI-30NB and SI-40NB IOLs using the Unfolder (Table O. Inclusion criteria allowed enrollment of patients 60 years or older with no pre-existing ocular pathology.
Table 1. Patient enrollment by investigational site. Number of Patients Site
SI-30NB
9
Figure 3.
(Olson) Cartridge with lens diagram.
SI-40NB
9
2
9
9
3
6
9
4
6
8
5
3
15
6
14
4
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CLINICAL EVALUATION OF THE UNFOLDER
Criteria
Rating
1. General rating of insertion system performance
3 5
1. Ease of grasping the cartridge 2. Ease of controlling IOL during loading 3. Ease of controlling IOL during insertion
Figure 4. (Olson) An SI-40NB 10L as it is extruded through the end of the Unfolder.
However, 4 patients were enrolled with preoperative pathologies: 2 with glaucoma and macular degeneration; 1 with mild macular pigment changes; 1 with Fuch's dystrophy and + 2 guttata. Of the 101 patients enrolled, all were available for the 1 day postoperative follow-up visit and 98 for the 2 week visit. All investigators performed cataract extraction using phacoemulsification. Lenses were implanted through corneal, limbal, or scleral incisions made with a surgical-grade steel or 2.5 to 3.2 mm diamond keratome (Figure 4). The following data were collected: clinical acceptability of the Unfolder based on investigator subjective assessment; incision size at three intervals during surgery; clinical results related to safety and efficacy. Investigators rated the clinical acceptability of the Unfolder using the following variables: overall performance; ease of grasping the cartridge; ease ofIOL control during insertion, unfolding, and capsular bag placement; and intraoperative IOL centration. Ratings were based on scales of 1 to 5, with investigators asked to compare the clinical performance of the Unfolder with that of insertion systems used before their participation in this study. Figure 5 shows additional details on criteria and rating scales. Previous IOL insertion techniques included the use of (1) forceps, (2) injector systems designed to insert plate IOLs, (3) the AMO PhacoFlex inserter. Investigators received written and verbal instruction by Allergan representatives on using the Unfolder before using it in the clinical setting. 1386
Description Unacceptable, much worse than usual Average, about the same as usual Excellent, much better than usual More difficult
3
Comparable
5
Easier
3
Comparable
5
Very well centered
4. Easl:l of controlling IOL during unfolding 5. Ease of controlling IOL during capsular bag placement Poorly centered
7. IOL centration
Figure 5. (Olson) Clinical acceptability criteria and associated five-point rating scales with half-point increments.
Investigators were asked to monitor IOLs in situ at two postoperative intervals (1 day and 2 weeks) to assess lens centration and lens clarity. In addition, they were asked to evaluate the condition of the lens haptics. Internal incision size was measured using a calibrated instrument (Steinert-Deacon Incision Gauges, Capital Instruments, Ltd.). The gauges ranged in width from 2.0 to 4.6 mm in 0.1 mm increments. The incision's internal dimension was measured three times during surgery: after initial incision, immediately after phacoemulsification but before IOL implantation, and after IOL implantation. In this paper, incision size refers to the incision's internal dimension. Although the primary focus of this evaluation was the clinical acceptability of the Unfolder, the following clinical data variables for safety and efficacy were also collected: intraoperative complications, postoperative visual acuity using standard Snellen acuity charts, postoperative complications, and adverse events. These data were collected intraoperatively and 1 day and 2 weeks postoperatively. The 2 week follow-up visit visual acuity data are presented. Postoperative astigmatism data were not collected.
] CATARACf REFRACf SURG-VOL 23, NOVEMBER 1997
CLINICAL EVALUATION OF THE UNFOLDER
Table 2. Overall clinical performance by investigational site. Site
Mean Rating" (±SD) 3.8 ± 1.0
2
4.4 ± 0.7
3
3.5 ± 0.1
4
4.0 ± 0.0
5
4.5 ± 0.5
6
3.4 ± 0.6
'On five-point scale with half-point increments: 1 = unacceptable, much worse than usual; 3 = average, about the same as usual; 5 = excellent, much better than usual
Results The overall clinical acceptability of the Unfolder was rated as better than or comparable to that of other injector systems in 96.8% (92/95; 3 not reported) of the cases. The overall clinical performance ratings by investigator ranged from 3.4 ± 0.6 (SO) to 4.5 ± 0.5 based on a scale of 1 to 5 (1 = unacceptable; 5 = excellent). Results by investigational site are shown in Table 2. Clinical acceptability ratings of additional variables are shown in Table 3. Mean ratings for each variable measured were as follows: ease of grasping lens cartridge, 4.3 ± 1.0; ease ofIOL control during loading, 3.6 ± 1.2; ease ofIOL control during insertion, 3.7 ± 0.8; ease of IOL control during unfolding, 3.9 ± 0.7; ease of IOL control during bag placement, 3.6 ± 0.5; intraoperative IOL centration, 4.7 ± 0.8.
Table 4 shows the mean incision sizes at the three intervals. Mean incision size after phacoemulsification but before IOL implantation was 3.0 ± 0.1 mm (range 2.7 to 3.2 mm). Mean incision size after IOL implantation was 3.1 ± 0.1 mm (range 2.9 to 3.3 mm), representing a mean increase of 0.1 mm. There were no reports of lens decentration, tilt, or rotation during the follow-up. All 98 lenses evaluated at the 2 week follow-up were well centered and optically clear. There were no reports of surface marks, debris on lens optics, or haptic deformation (i.e., crimping or kinking). At the 2 week visit, 94.6% of patients (88/93; 5 not reported) achieved a best corrected distance visual acuity of 20/40 or better; 31.2% (29/93; 5 not reported) achieved 20/20 or better. Five patients (5.4%, 5/93) did not achieve a best corrected distance visual acuity of 20/40 or better at 2 weeks: two had pre-existing glaucoma and macular degeneration, one had pre-existing Fuch's dystrophy and + 2 guttata, and two had mild to moderate corneal edema unrelated to Unfolder use that improved to 20/40 or better at subsequent visits. No surgical complications (e.g., posterior capsular rupture, iris damage, lens damage) were reported. In one case (1.0%, 11101), an IOL was released in the sulcus (both haptics). This lens was repositioned into the capsular bag at the time of surgery without difficulty. In one additional case (1.0%, 11101), an IOL was inverted upon release into the capsular bag. In this case, the lens was successfully rotated into the proper orien-
Table 3. Additional clinical acceptability assessments, mean ratings. Site
Performance Parameter
2
3
4
5
6
Mean (±SD) All Sites
Ease of grasping cartridge'
5.0
5.0
3.0
3.0
5.0
5.0
4.3 ± 1.0
Ease of IOL control during loading'
5.0
5.0
3.0
3.5
3.0
2.0
3.6 ± 1.2
Ease of IOL control during insertion'
4.0
5.0
3.0
3.0
3.0
4.0
3.7 ± 0.8
Ease of IOL control during unfolding'
4.0
5.0
4.0
3.5
4.0
3.0
3.9 ± 0.7
Ease of IOL control during bag placement'
3.5
4.0
4.0
3.0
4.0
3.0
3.6 ± 0.5
Intraoperative IOL centration t
5.0
5.0
3.0
5.0
5.0
5.0
4.7 ± 0.8
'Comparison to usual insertion system based on a five-point scale with half-point intervals: 1 system/instrument(s); 5 = easier than usual system/instrument(s).
= more
difficult; 3
= equal
to usual
tComparison of IOL centration with usual insertion system based on a five-point scale with half-point intervals: 1 = centered poorly; 3 = centered comparably; 5 = centered very well.
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CLINICAL EVALUATION OF THE UNFOLDER
Table 4.
Mean incision size by investigational site.
Mean Incision Size ± SO (mm) Initial
After Phaco
After IOL Implantation
3.0 ± 0.0
3.1 ± 0.1
3.1 ± 0.1
2
2.7 ± 0.1
2.9 ± 0.2
3.0 ± 0.2
3
3.0 ± 0.0
3.1 ± 0.0
3.1 ± 0.0
4
3.1 ± 0.0
3.2 ± 0.0
3.2 ± 0.0
5
3.0 ± 0.1
3.1 ± 0.1
3.1 ± 0.1
Site
6
2.9 ± 0.1
3.0 ± 0.1
3.1 ± 0.1
All
2.9 ± 0.2
3.0 ± 0.1
3.1 ± 0.1
tation. Both patients achieved a best corrected distance visual acuity of 20/20 2 weeks postoperatively. Four patients (4.1 %, 4/98) had slight postoperative complications not related to the Unfolder: capsular fibrosis, trace posterior capsule opacification, folds in Descemet's membrane, and + 1 blepharitis. There were no reports of adverse events during the study.
Discussion All investigators noted that the Unfolder allowed slow, controlled delivery ofIOLs into the capsular bag. Average ratings for the overall performance and for seven variables indicate that the Unfolder performed better than or comparable to previously used 10L implantation systems. There were no differences in the investigators' ability to successfully implant the SI-30NB or SI-40NB 10L using the Unfolder. All investigators required several cases to become fully comfortable with the Unfolder. Adequate instruction and training before use in the clinical setting are recommended to ensure optimal outcome. In recent years, a considerable amount of attention has been paid to "true" incision size. In a clinical study of incision size, Steinert and Deacon4 found that incision widening generally occurs after the initial keratome incision, when the initial incision is wider than the physical width of the keratome, and after phacoemulsification and irrigation/aspiration, when the incision is wider than initially.5 Incision widening is dependent on a variety of factors. One is the instruments used for 10L implantation. Using a cadaver eye model, Mackool and RussellS 1388
showed that the internal measurement of 3.0 mm incisions increased in width by 0.2 mm after 10L insertion using the Fine Universal II and Mackool II forceps; external incision size increased by 0.7 mm after implantation of a three-piece Staar lens using an injector. The Unfolder was designed for the implantation of PhacoFlex II 10Ls through 3.0 mm incisions. In this evaluation, lenses were implanted through a mean incisiun size of 3.0 mm (size after phacoemulsification but before 10L implantation). (One investigator performed 10L implantation through a mean incision size of 2.9 mm.) Mean incision size widening after 10L implantation was 0.1 mm, which is less than that reported by Mackool and RusselP (0.2 mm) with any 10L forceps or inserter system and by Steinert and Deacon4 for unwidened incisions (0.26 mm). In our study, all 10Ls were centered and there were no reports of 10L damage or surface marks on lens optics. No haptic deformation occurred intraoperatively or postoperatively. Most patients achieved excellent visual acuity results. The five who did not achieve a best corrected distance visual acuity of 20/40 or better had preexisting ocular pathologies or corneal edema unrelated to the use of the Unfolder. Two surgical-technique-related complications were reported: one 10L implanted in the sulcus rather than the capsular bag and one 10L released inverted into the capsular bag. These events were related to the learning curve associated with the Unfolder; both lenses were properly positioned in the capsular bag before the end of surgery. No postoperative complications or adverse events were reported during the study. The results of this clinical evaluation indicate that the Unfolder is clinically acceptable and easy to use and provides controlled lens implantation through 2.7 to 3.2 mm incisions.
References 1. Sanders DR, El Maghraby A, Kraff MC, Berkeley RG.
Advantages of small-incision surgery. In: Gills]P, Sanders DR, eds, Small-Incision Cataract Surgery; Foldable Lenses, One-Stitch Surgery, Sutureless Surgery, Astigmatic Keratotomy. Thorofare, N], Slack, 1990; 3-13 2. Steinert RF, Brint SF, White SM, Fine IH. Astigmatism after small incision cataract surgery; a prospective, randomized, multicenter comparison of 4- and 6.5-mm incisions. Ophthalmology 1991; 98:417-423
J CATARACT REFRACT SURG-VOL 23, NOVEMBER 1997
CLINICAL EVALUATION OF THE UNFOLDER
3. Oshika T, Tsuboi S, Yaguchi S, et al. Comparative study of intraocular lens implantation through 3.2- and 5.5 mm incisions. Ophthalmology 1994; 101: 1183-1190 4. Steinert RF, Deacon J. Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery. Ophthalmology 1996; 103:220-225 5. Mackool RJ, Russell RS. Effect of foldable intraocular lens insertion on incision width. J Cataract Refract Surg 1996; 22:571-574
Investigators Randall Olson, MD, University of Utah, Salt Lake City, Utah; Robert Cameron, MD, Abilene Regional Medical Center, Abilene, Texas; Todd Hovis, MD, Columbus Community Hospital, Columbus, Texas; John Hunkeler, MD, University of Kamas/Kamas City, Kansas City, Missouri; Richard Lindstrom, MD, Phillips Eye Imtitute, Minneapolis, Minnesota; Roger Steinert, MD, Harvard Medical School Boston, Massachusetts.
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ABSTRACT Purpose: To evaluate the clinical acceptability of the Unfolder™ for implantation of AMO® PhacoFlex II® (model SI-30NB or SI-40NB) intraocular lenses (IOLs). Setting: Six investigational sites in five states in the United States: Utah, Texas, Missouri, Minnesota, and Massachusetts. Methods: One hundred one patients from six investigational sites had implantation of an SI-30NB or SI-40NB IOL. Investigators evaluated the clinical acceptability of the Unfolder by comparing their experience with the injector with that using other implantation systems. Internal incision size (dimensions) was measured three times during surgery using a calibrated instrument. Data on safety and efficacy were collected. Results: The investigators rated the Unfolder as clinically acceptable. Mean internal incision size after phacoemulsification but before IOL implantation was 3.0 mm ± 0.1 (SO) (range 2.7 to 3.2 mm). Average internal incision size after IOL implantation was 3.1 ± 0.1 mm. There were no reports of haptic deformation, lens optic damage, or postoperative complications related to the Unfolder. No adverse events were reported. Conclusions: Investigators found the Unfolder easy to use. It provided controlled lens implantation through incisions 2.7 to 3.2 mm, with post-IOL implantation incisions ranging from 2.9 to 3.3 mm. J Cataract Refract Surg 1997; 23: 1384-1389
T
he benefits of small incision surgery are well documented and include rapid visual rehabilitation,I,2 reduced postoperative astigmatism,I,2 and decreased postoperative inflammation. I,3 One method of foldable intraocular lens (IOL) implantation that uses the benefits of small incisions is the lens injector.
Presented in part at the 1997 Royal Hawaiian Eye, Honolulu, Hawaii, USA, January 1997, and the Symposium on Cataract, IOL and Refractive Surgery, Boston, Massachusetts, USA, April 1997. Supported in part by Allergan and by a grant from Research to Prevent Blindness, Inc., New York, New York, USA, to the Department of Ophthalmology, University of Utah. Reprint requests to Randall Olson, MD, 50 North Medical Drive, Salt Lake City, Utah 84132, USA. 1384
The Unfolder™ (AMO® PhacoFlex II® SoITipTM insertion system, Allergan) is designed to implant AMO PhacoFlex II silicone monofocal IOL models SI-30NB and SI-40NB through incisions ranging in size from 2.7 to 3.2 mm. The Unfolder consists of a disposable cartridge with a central, sliding, reusable handpiece rod composed of titanium (Figure 1). The inserter has a soft silicone tip that is applied to the handpiece rod before use (Figure 2) to prevent direct contact between the titanium rod and silicone optic. It is designed to gently guide lenses through the lens cartridge, minimizing lens distortion and facilitating controlled lens release. The cartridge has an image of a lens etched into the surface of the wing (Figure 3). This image shows the
J CATARACT REFRACT SURG-VOL 23, NOVEMBER 1997
CLINICAL EVALUATION OF THE UNFOLDER
Figure 1. (Olson) Unfolder system components.
Figure 2. (Olson) Application of the soft tip on the handpiece rod.
proper lens placement before the cartridge is closed. The clear cartridge and the side-view window on the handpiece allow the surgeon to visualize the leading haptic and verify its correct position before the lens is injected into the eye. A bench-top, in vitro analysis of the Unfolder was performed to determine whether the device reliably delivers SI-30NB and SI-40NB lenses in a controlled manner without significantly affecting optical performance, lens dimensions, or cosmetic appearance. Seventytwo SI-30NB and SI-40NB IOLs with polypropylene and poly(methyl methacrylate) haptics, respectively, were used in the evaluation. Simulated lens insertion showed that there were minimal changes to the physical
and optical characteristics of IOLs (unpublished data, Allergan, 1996). The current study assessed the clinical acceptability of the Unfolder in the implantation of SI-30NB and SI-40NB IOLs.
Patients and Methods An open-label, noncomparative evaluation of the Unfolder was conducted by six investigators at six investigational sites. Each investigator implanted SI-30NB and SI-40NB IOLs using the Unfolder (Table O. Inclusion criteria allowed enrollment of patients 60 years or older with no pre-existing ocular pathology.
Table 1. Patient enrollment by investigational site. Number of Patients Site
SI-30NB
9
Figure 3.
(Olson) Cartridge with lens diagram.
SI-40NB
9
2
9
9
3
6
9
4
6
8
5
3
15
6
14
4
J CATARACT REFRACT SURG-VOL 23, NOVEMBER 1997
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CLINICAL EVALUATION OF THE UNFOLDER
Criteria
Rating
1. General rating of insertion system performance
3 5
1. Ease of grasping the cartridge 2. Ease of controlling IOL during loading 3. Ease of controlling IOL during insertion
Figure 4. (Olson) An SI-40NB 10L as it is extruded through the end of the Unfolder.
However, 4 patients were enrolled with preoperative pathologies: 2 with glaucoma and macular degeneration; 1 with mild macular pigment changes; 1 with Fuch's dystrophy and + 2 guttata. Of the 101 patients enrolled, all were available for the 1 day postoperative follow-up visit and 98 for the 2 week visit. All investigators performed cataract extraction using phacoemulsification. Lenses were implanted through corneal, limbal, or scleral incisions made with a surgical-grade steel or 2.5 to 3.2 mm diamond keratome (Figure 4). The following data were collected: clinical acceptability of the Unfolder based on investigator subjective assessment; incision size at three intervals during surgery; clinical results related to safety and efficacy. Investigators rated the clinical acceptability of the Unfolder using the following variables: overall performance; ease of grasping the cartridge; ease ofIOL control during insertion, unfolding, and capsular bag placement; and intraoperative IOL centration. Ratings were based on scales of 1 to 5, with investigators asked to compare the clinical performance of the Unfolder with that of insertion systems used before their participation in this study. Figure 5 shows additional details on criteria and rating scales. Previous IOL insertion techniques included the use of (1) forceps, (2) injector systems designed to insert plate IOLs, (3) the AMO PhacoFlex inserter. Investigators received written and verbal instruction by Allergan representatives on using the Unfolder before using it in the clinical setting. 1386
Description Unacceptable, much worse than usual Average, about the same as usual Excellent, much better than usual More difficult
3
Comparable
5
Easier
3
Comparable
5
Very well centered
4. Easl:l of controlling IOL during unfolding 5. Ease of controlling IOL during capsular bag placement Poorly centered
7. IOL centration
Figure 5. (Olson) Clinical acceptability criteria and associated five-point rating scales with half-point increments.
Investigators were asked to monitor IOLs in situ at two postoperative intervals (1 day and 2 weeks) to assess lens centration and lens clarity. In addition, they were asked to evaluate the condition of the lens haptics. Internal incision size was measured using a calibrated instrument (Steinert-Deacon Incision Gauges, Capital Instruments, Ltd.). The gauges ranged in width from 2.0 to 4.6 mm in 0.1 mm increments. The incision's internal dimension was measured three times during surgery: after initial incision, immediately after phacoemulsification but before IOL implantation, and after IOL implantation. In this paper, incision size refers to the incision's internal dimension. Although the primary focus of this evaluation was the clinical acceptability of the Unfolder, the following clinical data variables for safety and efficacy were also collected: intraoperative complications, postoperative visual acuity using standard Snellen acuity charts, postoperative complications, and adverse events. These data were collected intraoperatively and 1 day and 2 weeks postoperatively. The 2 week follow-up visit visual acuity data are presented. Postoperative astigmatism data were not collected.
] CATARACf REFRACf SURG-VOL 23, NOVEMBER 1997
CLINICAL EVALUATION OF THE UNFOLDER
Table 2. Overall clinical performance by investigational site. Site
Mean Rating" (±SD) 3.8 ± 1.0
2
4.4 ± 0.7
3
3.5 ± 0.1
4
4.0 ± 0.0
5
4.5 ± 0.5
6
3.4 ± 0.6
'On five-point scale with half-point increments: 1 = unacceptable, much worse than usual; 3 = average, about the same as usual; 5 = excellent, much better than usual
Results The overall clinical acceptability of the Unfolder was rated as better than or comparable to that of other injector systems in 96.8% (92/95; 3 not reported) of the cases. The overall clinical performance ratings by investigator ranged from 3.4 ± 0.6 (SO) to 4.5 ± 0.5 based on a scale of 1 to 5 (1 = unacceptable; 5 = excellent). Results by investigational site are shown in Table 2. Clinical acceptability ratings of additional variables are shown in Table 3. Mean ratings for each variable measured were as follows: ease of grasping lens cartridge, 4.3 ± 1.0; ease ofIOL control during loading, 3.6 ± 1.2; ease ofIOL control during insertion, 3.7 ± 0.8; ease of IOL control during unfolding, 3.9 ± 0.7; ease of IOL control during bag placement, 3.6 ± 0.5; intraoperative IOL centration, 4.7 ± 0.8.
Table 4 shows the mean incision sizes at the three intervals. Mean incision size after phacoemulsification but before IOL implantation was 3.0 ± 0.1 mm (range 2.7 to 3.2 mm). Mean incision size after IOL implantation was 3.1 ± 0.1 mm (range 2.9 to 3.3 mm), representing a mean increase of 0.1 mm. There were no reports of lens decentration, tilt, or rotation during the follow-up. All 98 lenses evaluated at the 2 week follow-up were well centered and optically clear. There were no reports of surface marks, debris on lens optics, or haptic deformation (i.e., crimping or kinking). At the 2 week visit, 94.6% of patients (88/93; 5 not reported) achieved a best corrected distance visual acuity of 20/40 or better; 31.2% (29/93; 5 not reported) achieved 20/20 or better. Five patients (5.4%, 5/93) did not achieve a best corrected distance visual acuity of 20/40 or better at 2 weeks: two had pre-existing glaucoma and macular degeneration, one had pre-existing Fuch's dystrophy and + 2 guttata, and two had mild to moderate corneal edema unrelated to Unfolder use that improved to 20/40 or better at subsequent visits. No surgical complications (e.g., posterior capsular rupture, iris damage, lens damage) were reported. In one case (1.0%, 11101), an IOL was released in the sulcus (both haptics). This lens was repositioned into the capsular bag at the time of surgery without difficulty. In one additional case (1.0%, 11101), an IOL was inverted upon release into the capsular bag. In this case, the lens was successfully rotated into the proper orien-
Table 3. Additional clinical acceptability assessments, mean ratings. Site
Performance Parameter
2
3
4
5
6
Mean (±SD) All Sites
Ease of grasping cartridge'
5.0
5.0
3.0
3.0
5.0
5.0
4.3 ± 1.0
Ease of IOL control during loading'
5.0
5.0
3.0
3.5
3.0
2.0
3.6 ± 1.2
Ease of IOL control during insertion'
4.0
5.0
3.0
3.0
3.0
4.0
3.7 ± 0.8
Ease of IOL control during unfolding'
4.0
5.0
4.0
3.5
4.0
3.0
3.9 ± 0.7
Ease of IOL control during bag placement'
3.5
4.0
4.0
3.0
4.0
3.0
3.6 ± 0.5
Intraoperative IOL centration t
5.0
5.0
3.0
5.0
5.0
5.0
4.7 ± 0.8
'Comparison to usual insertion system based on a five-point scale with half-point intervals: 1 system/instrument(s); 5 = easier than usual system/instrument(s).
= more
difficult; 3
= equal
to usual
tComparison of IOL centration with usual insertion system based on a five-point scale with half-point intervals: 1 = centered poorly; 3 = centered comparably; 5 = centered very well.
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CLINICAL EVALUATION OF THE UNFOLDER
Table 4.
Mean incision size by investigational site.
Mean Incision Size ± SO (mm) Initial
After Phaco
After IOL Implantation
3.0 ± 0.0
3.1 ± 0.1
3.1 ± 0.1
2
2.7 ± 0.1
2.9 ± 0.2
3.0 ± 0.2
3
3.0 ± 0.0
3.1 ± 0.0
3.1 ± 0.0
4
3.1 ± 0.0
3.2 ± 0.0
3.2 ± 0.0
5
3.0 ± 0.1
3.1 ± 0.1
3.1 ± 0.1
Site
6
2.9 ± 0.1
3.0 ± 0.1
3.1 ± 0.1
All
2.9 ± 0.2
3.0 ± 0.1
3.1 ± 0.1
tation. Both patients achieved a best corrected distance visual acuity of 20/20 2 weeks postoperatively. Four patients (4.1 %, 4/98) had slight postoperative complications not related to the Unfolder: capsular fibrosis, trace posterior capsule opacification, folds in Descemet's membrane, and + 1 blepharitis. There were no reports of adverse events during the study.
Discussion All investigators noted that the Unfolder allowed slow, controlled delivery ofIOLs into the capsular bag. Average ratings for the overall performance and for seven variables indicate that the Unfolder performed better than or comparable to previously used 10L implantation systems. There were no differences in the investigators' ability to successfully implant the SI-30NB or SI-40NB 10L using the Unfolder. All investigators required several cases to become fully comfortable with the Unfolder. Adequate instruction and training before use in the clinical setting are recommended to ensure optimal outcome. In recent years, a considerable amount of attention has been paid to "true" incision size. In a clinical study of incision size, Steinert and Deacon4 found that incision widening generally occurs after the initial keratome incision, when the initial incision is wider than the physical width of the keratome, and after phacoemulsification and irrigation/aspiration, when the incision is wider than initially.5 Incision widening is dependent on a variety of factors. One is the instruments used for 10L implantation. Using a cadaver eye model, Mackool and RussellS 1388
showed that the internal measurement of 3.0 mm incisions increased in width by 0.2 mm after 10L insertion using the Fine Universal II and Mackool II forceps; external incision size increased by 0.7 mm after implantation of a three-piece Staar lens using an injector. The Unfolder was designed for the implantation of PhacoFlex II 10Ls through 3.0 mm incisions. In this evaluation, lenses were implanted through a mean incisiun size of 3.0 mm (size after phacoemulsification but before 10L implantation). (One investigator performed 10L implantation through a mean incision size of 2.9 mm.) Mean incision size widening after 10L implantation was 0.1 mm, which is less than that reported by Mackool and RusselP (0.2 mm) with any 10L forceps or inserter system and by Steinert and Deacon4 for unwidened incisions (0.26 mm). In our study, all 10Ls were centered and there were no reports of 10L damage or surface marks on lens optics. No haptic deformation occurred intraoperatively or postoperatively. Most patients achieved excellent visual acuity results. The five who did not achieve a best corrected distance visual acuity of 20/40 or better had preexisting ocular pathologies or corneal edema unrelated to the use of the Unfolder. Two surgical-technique-related complications were reported: one 10L implanted in the sulcus rather than the capsular bag and one 10L released inverted into the capsular bag. These events were related to the learning curve associated with the Unfolder; both lenses were properly positioned in the capsular bag before the end of surgery. No postoperative complications or adverse events were reported during the study. The results of this clinical evaluation indicate that the Unfolder is clinically acceptable and easy to use and provides controlled lens implantation through 2.7 to 3.2 mm incisions.
References 1. Sanders DR, El Maghraby A, Kraff MC, Berkeley RG.
Advantages of small-incision surgery. In: Gills]P, Sanders DR, eds, Small-Incision Cataract Surgery; Foldable Lenses, One-Stitch Surgery, Sutureless Surgery, Astigmatic Keratotomy. Thorofare, N], Slack, 1990; 3-13 2. Steinert RF, Brint SF, White SM, Fine IH. Astigmatism after small incision cataract surgery; a prospective, randomized, multicenter comparison of 4- and 6.5-mm incisions. Ophthalmology 1991; 98:417-423
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3. Oshika T, Tsuboi S, Yaguchi S, et al. Comparative study of intraocular lens implantation through 3.2- and 5.5 mm incisions. Ophthalmology 1994; 101: 1183-1190 4. Steinert RF, Deacon J. Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery. Ophthalmology 1996; 103:220-225 5. Mackool RJ, Russell RS. Effect of foldable intraocular lens insertion on incision width. J Cataract Refract Surg 1996; 22:571-574
Investigators Randall Olson, MD, University of Utah, Salt Lake City, Utah; Robert Cameron, MD, Abilene Regional Medical Center, Abilene, Texas; Todd Hovis, MD, Columbus Community Hospital, Columbus, Texas; John Hunkeler, MD, University of Kamas/Kamas City, Kansas City, Missouri; Richard Lindstrom, MD, Phillips Eye Imtitute, Minneapolis, Minnesota; Roger Steinert, MD, Harvard Medical School Boston, Massachusetts.
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