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Silicone plate-haptic lens injection without prior incision enlargement
techniques
Silicone plate-haptic lens injection without prior incision enlargement Andrew G. Coombes, FRCOphth, Richard Sheard, FRCOphth, David S. Gartry, MD, FRCOphth, Bruce D. Allan, MD, FRCOphth ABSTRACT Injection devices are routinely used to implant silicone plate-haptic intraocular lenses (IOLs). The injector cannula is normally introduced directly into the anterior chamber prior to injection, either after deliberate wound enlargement or by forcible entry with significant wound stretching. We present a technique for injecting the lens through the wound in which apposition is maintained between the injector tip and the unenlarged phaco incision. In 25 eyes, the wound enlarged after IOL implantation by a mean of 0.13 mm ⫾ 0.05 (SD), representing a 4.0% increase in width. We have found this modified technique to be safe, effective, and reproducible. J Cataract Refract Surg 2001; 27:1542–1544 © 2001 ASCRS and ESCRS
I
njection devices simplify intraocular lens (IOL) implantation and avoid the risk of lens contamination prior to insertion. The cannula of the injection device is usually inserted though the incision and into the anterior chamber prior to injection. A mismatch between the rigid exterior cross-section of the injector and the capacity of a standard phacoemulsification incision may cause significant wound stretching during injector introduction.1 This can be avoided by surgically enlarging the primary incision before IOL insertion.2 However, this additional surgical step may damage the intraocular Accepted for publication March 19, 2001. From the Anterior Segment Service, Moorfields Eye Hospital, London, United Kingdom. Presented in part at the annual congress of the Royal College of Ophthalmologists, Harrogate, England, April 2000. None of the authors has a financial or proprietary interest in any material or method mentioned. Reprint requests to Mr. Andrew Coombes, Anterior Segment Service, Moorfields Eye Hospital, London EC1V 2PD, United Kingdom. E-mail: [email protected]. © 2001 ASCRS and ESCRS Published by Elsevier Science Inc.
structures or lead to wound-related complications. We present a modified technique that avoids significant wound stretching and deliberate enlargement before IOL implantation using a lens injector.
Surgical Technique After standard phacoemulsification though a triplanar or biplanar 3.2 mm corneal incision and cortex aspiration, the capsular bag and anterior chamber are filled with enough viscoelastic substance to open the capsular bag. A Passport™ II injector (Bausch & Lomb) is loaded with a C11UB plate-haptic silicone IOL (Bausch & Lomb) as directed by the manufacturer, and the IOL is advanced to the tip of the implantation cannula. Bevel down, the cannula tip is placed into, but not forced through, the corneal wound (Figure 1). Pressure is applied to hold the injector in place while it is directed toward the center of the capsulorhexis (Figure 2). The cannula does not enter the anterior chamber. The plunger is then advanced in a smooth, continuous movement while pressure is maintained to hold the 0886-3350/01/$–see front matter PII S0886-3350(01)00975-0
TECHNIQUES: COOMBES
Figure 1. (Coombes) The cannula tip is placed bevel down within, but not through, the corneal wound.
Figure 2. (Coombes) Pressure is applied to hold the injector in place while it is directed toward the center of the capsulorhexis. The plunger is then advanced in a smooth, continuous movement.
bevel in the incision. The leading haptic directly enters the capsular bag (Figure 3). Although the trailing haptic may follow, it usually lies within the anterior chamber. From here, the trailing haptic can be easily flipped into the capsular bag by downward pressure over the optic– haptic junction. To avoid additional instrumentation, this can be accomplished by using the irrigation/aspiration cannula, which is then in position to commence removal of the viscoelastic substance.
Results The internal wound dimensions in 25 eyes were measured using a Deacon-Steinert measure before and after IOL implantation. The mean increase in incision width was 0.13 mm ⫾ 0.05 (SD). The mean incision width was 3.24 ⫾ 0.05 mm after phacoemulsification and before IOL implantation and 3.37 ⫾ 0.07 mm after lens insertion, representing a 4.0% width increase.
Discussion Although we have used this technique in hundreds of cases and have not experienced wound-related complications, we were concerned that the IOL may partly open in the wound, stretching or tearing the primary incision. However, stretching appears to have been minimal with this technique and compares favorably with the results of recent studies using different injection devices and implantation forceps.3,4 In 1996, Steinert and Deacon5 reported an enlarged incision width with fold-
Figure 3. (Coombes) The leading haptic directly enters the capsular bag while the trailing haptic is delivered into the anterior chamber.
able IOLs including a small group of Chiron C10 lenses, a plate-haptic silicone IOL that preceded the C11UB design, inserted using a Passport injector. In these patients, the mean increase in incision width was 0.28 mm or 9%; however, the mean width before IOL implantation was 3.06 mm compared with 3.24 mm in our group. Although evolved independently at Moorfields Eye Hospital, the technique we describe is not novel. In a cadaver eye study of incision stretching, Kohnen and coauthors6 used a similar method of lens injection in which the injector was inserted at 20% to 30% depth within a phaco incision. We also are aware that an analogous technique has been presented at several ophthalmic meetings in the United States. However, both
J CATARACT REFRACT SURG—VOL 27, OCTOBER 2001
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TECHNIQUES: COOMBES
planned wound enlargement and forced stretching are still widely used to accommodate the exterior diameter of rigid lens injectors for lens injection from within the anterior chamber. Scanning electron microscopy has shown tearing of corneal structures after IOL implantation using an injector through small incisions.1 It has been suggested that foldable IOLs should not be inserted under pressure and that to facilitate implantation, the primary incision should be surgically enlarged prior to IOL insertion.2 This avoids deformation and lateral tearing of the wound, preserves the incision structure, and reduces the risk of anterior chamber leakage at its outer extremes. However, deliberate enlargement of the primary incision is an additional surgical step that risks damage to the intraocular structures, in particular the anterior capsule. Furthermore, unless a specific wound blade is used, enlargement may be imprecise and lead to induced astigmatism or wound-related complications (eg, postoperative aqueous leak). Our modified technique, in which the bevel of the injector is placed within the unenlarged wound, avoids this risk. In the modified injection technique, the IOL opens in the capsular bag and the anterior chamber. Silicone plate-haptic lenses tend to unfold rapidly. When these lenses are placed directly into the capsular bag, the unfolding forces may cause zonular damage or capsule rupture.7 We have not experienced these complications and postulate that because the IOL does not open solely in the capsular bag, the unfolding forces are dissipated, which may reduce the risk of capsule damage. The only complication we have encountered is occasional unfolding of the IOL outside the eye resulting from insufficient pressure between the injector tip and the wound during injection. In these circumstances, the same IOL may be washed, reloaded, and reinjected using the same technique. This complication is less likely to occur under topical anesthesia in which counterbal-
1544
ancing ocular muscle tone aids the maintenance of injector tip to wound apposition during injection. Alternatively, because the lens injector plunger can be operated with 1 hand, countertraction may be applied at the limbus using a forceps held in the free hand. Overfilling the anterior chamber with viscoelastic material can also hinder injection and predispose the lens to unfolding exterior to the eye. In conclusion, we found this modified technique of implanting an injectable silicone plate-haptic IOL to be safe, effective, and reproducible. Although the Bausch & Lomb C11UB IOL and Passport II injection system were used, the technique should be applicable to other lens injection systems.
References 1. Kohnen T, Koch DD. Experimental and clinical evaluation of incision size and shape following forceps and injector implantation of a three-piece high-refractive-index silicone intraocular lens. Graefes Arch Clin Exp Ophthalmol 1998; 236:922–928 2. Moreno-Montan˜ e´s J, Garcı´a-Layana A, Aliseda D, Munuera, JM. Variation in clear cornea incision size after phacoemulsification and foldable lens implantation. J Cataract Refract Surg 1998; 24:931–934 3. Mamalis N. Incision width after phacoemulsification with foldable intraocular lens implantation. J Cataract Refract Surg 2000; 26:237–241 4. Moreno-Montan˜e´s J, Maldonado MJ, Garcı´a-Layana A, et al. Final clear corneal incision size for AcrySof intraocular lenses. J Cataract Refract Surg 1999; 25:959 –963 5. Steinert RF, Deacon J. Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery. Ophthalmology 1996; 103:220 –225 6. Kohnen T, Lambert RJ, Koch DD. Incision sizes for foldable intraocular lenses. Ophthalmology 1997; 104:1277– 1286 7. Negi A, Sinha A. Posterior capsule tear with plate-haptic silicone intraocular lens dislocation. J Cataract Refract Surg 2000; 26:1558 –1559
J CATARACT REFRACT SURG—VOL 27, OCTOBER 2001
Silicone plate-haptic lens injection without prior incision enlargement Andrew G. Coombes, FRCOphth, Richard Sheard, FRCOphth, David S. Gartry, MD, FRCOphth, Bruce D. Allan, MD, FRCOphth ABSTRACT Injection devices are routinely used to implant silicone plate-haptic intraocular lenses (IOLs). The injector cannula is normally introduced directly into the anterior chamber prior to injection, either after deliberate wound enlargement or by forcible entry with significant wound stretching. We present a technique for injecting the lens through the wound in which apposition is maintained between the injector tip and the unenlarged phaco incision. In 25 eyes, the wound enlarged after IOL implantation by a mean of 0.13 mm ⫾ 0.05 (SD), representing a 4.0% increase in width. We have found this modified technique to be safe, effective, and reproducible. J Cataract Refract Surg 2001; 27:1542–1544 © 2001 ASCRS and ESCRS
I
njection devices simplify intraocular lens (IOL) implantation and avoid the risk of lens contamination prior to insertion. The cannula of the injection device is usually inserted though the incision and into the anterior chamber prior to injection. A mismatch between the rigid exterior cross-section of the injector and the capacity of a standard phacoemulsification incision may cause significant wound stretching during injector introduction.1 This can be avoided by surgically enlarging the primary incision before IOL insertion.2 However, this additional surgical step may damage the intraocular Accepted for publication March 19, 2001. From the Anterior Segment Service, Moorfields Eye Hospital, London, United Kingdom. Presented in part at the annual congress of the Royal College of Ophthalmologists, Harrogate, England, April 2000. None of the authors has a financial or proprietary interest in any material or method mentioned. Reprint requests to Mr. Andrew Coombes, Anterior Segment Service, Moorfields Eye Hospital, London EC1V 2PD, United Kingdom. E-mail: [email protected]. © 2001 ASCRS and ESCRS Published by Elsevier Science Inc.
structures or lead to wound-related complications. We present a modified technique that avoids significant wound stretching and deliberate enlargement before IOL implantation using a lens injector.
Surgical Technique After standard phacoemulsification though a triplanar or biplanar 3.2 mm corneal incision and cortex aspiration, the capsular bag and anterior chamber are filled with enough viscoelastic substance to open the capsular bag. A Passport™ II injector (Bausch & Lomb) is loaded with a C11UB plate-haptic silicone IOL (Bausch & Lomb) as directed by the manufacturer, and the IOL is advanced to the tip of the implantation cannula. Bevel down, the cannula tip is placed into, but not forced through, the corneal wound (Figure 1). Pressure is applied to hold the injector in place while it is directed toward the center of the capsulorhexis (Figure 2). The cannula does not enter the anterior chamber. The plunger is then advanced in a smooth, continuous movement while pressure is maintained to hold the 0886-3350/01/$–see front matter PII S0886-3350(01)00975-0
TECHNIQUES: COOMBES
Figure 1. (Coombes) The cannula tip is placed bevel down within, but not through, the corneal wound.
Figure 2. (Coombes) Pressure is applied to hold the injector in place while it is directed toward the center of the capsulorhexis. The plunger is then advanced in a smooth, continuous movement.
bevel in the incision. The leading haptic directly enters the capsular bag (Figure 3). Although the trailing haptic may follow, it usually lies within the anterior chamber. From here, the trailing haptic can be easily flipped into the capsular bag by downward pressure over the optic– haptic junction. To avoid additional instrumentation, this can be accomplished by using the irrigation/aspiration cannula, which is then in position to commence removal of the viscoelastic substance.
Results The internal wound dimensions in 25 eyes were measured using a Deacon-Steinert measure before and after IOL implantation. The mean increase in incision width was 0.13 mm ⫾ 0.05 (SD). The mean incision width was 3.24 ⫾ 0.05 mm after phacoemulsification and before IOL implantation and 3.37 ⫾ 0.07 mm after lens insertion, representing a 4.0% width increase.
Discussion Although we have used this technique in hundreds of cases and have not experienced wound-related complications, we were concerned that the IOL may partly open in the wound, stretching or tearing the primary incision. However, stretching appears to have been minimal with this technique and compares favorably with the results of recent studies using different injection devices and implantation forceps.3,4 In 1996, Steinert and Deacon5 reported an enlarged incision width with fold-
Figure 3. (Coombes) The leading haptic directly enters the capsular bag while the trailing haptic is delivered into the anterior chamber.
able IOLs including a small group of Chiron C10 lenses, a plate-haptic silicone IOL that preceded the C11UB design, inserted using a Passport injector. In these patients, the mean increase in incision width was 0.28 mm or 9%; however, the mean width before IOL implantation was 3.06 mm compared with 3.24 mm in our group. Although evolved independently at Moorfields Eye Hospital, the technique we describe is not novel. In a cadaver eye study of incision stretching, Kohnen and coauthors6 used a similar method of lens injection in which the injector was inserted at 20% to 30% depth within a phaco incision. We also are aware that an analogous technique has been presented at several ophthalmic meetings in the United States. However, both
J CATARACT REFRACT SURG—VOL 27, OCTOBER 2001
1543
TECHNIQUES: COOMBES
planned wound enlargement and forced stretching are still widely used to accommodate the exterior diameter of rigid lens injectors for lens injection from within the anterior chamber. Scanning electron microscopy has shown tearing of corneal structures after IOL implantation using an injector through small incisions.1 It has been suggested that foldable IOLs should not be inserted under pressure and that to facilitate implantation, the primary incision should be surgically enlarged prior to IOL insertion.2 This avoids deformation and lateral tearing of the wound, preserves the incision structure, and reduces the risk of anterior chamber leakage at its outer extremes. However, deliberate enlargement of the primary incision is an additional surgical step that risks damage to the intraocular structures, in particular the anterior capsule. Furthermore, unless a specific wound blade is used, enlargement may be imprecise and lead to induced astigmatism or wound-related complications (eg, postoperative aqueous leak). Our modified technique, in which the bevel of the injector is placed within the unenlarged wound, avoids this risk. In the modified injection technique, the IOL opens in the capsular bag and the anterior chamber. Silicone plate-haptic lenses tend to unfold rapidly. When these lenses are placed directly into the capsular bag, the unfolding forces may cause zonular damage or capsule rupture.7 We have not experienced these complications and postulate that because the IOL does not open solely in the capsular bag, the unfolding forces are dissipated, which may reduce the risk of capsule damage. The only complication we have encountered is occasional unfolding of the IOL outside the eye resulting from insufficient pressure between the injector tip and the wound during injection. In these circumstances, the same IOL may be washed, reloaded, and reinjected using the same technique. This complication is less likely to occur under topical anesthesia in which counterbal-
1544
ancing ocular muscle tone aids the maintenance of injector tip to wound apposition during injection. Alternatively, because the lens injector plunger can be operated with 1 hand, countertraction may be applied at the limbus using a forceps held in the free hand. Overfilling the anterior chamber with viscoelastic material can also hinder injection and predispose the lens to unfolding exterior to the eye. In conclusion, we found this modified technique of implanting an injectable silicone plate-haptic IOL to be safe, effective, and reproducible. Although the Bausch & Lomb C11UB IOL and Passport II injection system were used, the technique should be applicable to other lens injection systems.
References 1. Kohnen T, Koch DD. Experimental and clinical evaluation of incision size and shape following forceps and injector implantation of a three-piece high-refractive-index silicone intraocular lens. Graefes Arch Clin Exp Ophthalmol 1998; 236:922–928 2. Moreno-Montan˜ e´s J, Garcı´a-Layana A, Aliseda D, Munuera, JM. Variation in clear cornea incision size after phacoemulsification and foldable lens implantation. J Cataract Refract Surg 1998; 24:931–934 3. Mamalis N. Incision width after phacoemulsification with foldable intraocular lens implantation. J Cataract Refract Surg 2000; 26:237–241 4. Moreno-Montan˜e´s J, Maldonado MJ, Garcı´a-Layana A, et al. Final clear corneal incision size for AcrySof intraocular lenses. J Cataract Refract Surg 1999; 25:959 –963 5. Steinert RF, Deacon J. Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery. Ophthalmology 1996; 103:220 –225 6. Kohnen T, Lambert RJ, Koch DD. Incision sizes for foldable intraocular lenses. Ophthalmology 1997; 104:1277– 1286 7. Negi A, Sinha A. Posterior capsule tear with plate-haptic silicone intraocular lens dislocation. J Cataract Refract Surg 2000; 26:1558 –1559
J CATARACT REFRACT SURG—VOL 27, OCTOBER 2001