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Haptic misfolding during aspheric IOL insertion
208
CORRESPONDENCE
Haptic misfolding during aspheric IOL insertion
AcrySof intraocular lenses (IOLs) (Alcon, Inc.) are very popular. Several authors have described problems with the injection of this IOL using the Monarch cartridge system (Alcon, Inc.), including damage to the IOL on loading, entrapment of the trailing haptic within the cartridge, and sticking of the leading haptic to the optic.1–3 The AcrySert injection system (Alcon, Inc.) aims to resolve several of these problems. Despite using the AcrySert injector, we have found that the leading haptic has a tendency to “misfold” and position itself in a reverse configuration within the capsular bag. This situation can result in the optic rotating and potentially coming into contact with the endothelium or being inserted upside down. To compensate for misfolding, the surgeon must pronate his or her wrist, rotating the injector clockwise so the leading haptic unfolds in a reverse “S” within the capsular bag before rotating it counterclockwise; this allows the optic and trailing haptics to align correctly. These compensatory maneuvers are likely to increase the subjective difficulty of this stage of cataract surgery. When the pupil is poorly dilated and the capsulorhexis small, a misfolded leading haptic may not be recognized by a surgeon unaware of this problem. This can result in reversal or tilting of the optic within the
bag, causing a refractive surprise or lens-induced astigmatism. By systematically analyzing surgical videos, we have seen that the leading haptic has a tendency to fold in on itself incompletely as it travels forward within the nozzle of the cartridge and remains pointing straight along the barrel of the cartridge in approximately 40% of cases (Video, available at http://jcrsjournal.org). If no compensatory maneuvers are made, when the IOL is released into the capsular bag, the distal tip of the leading haptic engages the capsule and remains relatively fixed. As the remainder of the IOL is injected, the resultant force pushes on the haptic and is transferred forward into the capsule and zonules and backward toward the optic, causing the IOL to rotate clockwise around an axis perpendicular to the optic plane. The haptic usually remains misaligned following IOL insertion, and manual dialing/repositioning of the IOL is required. These maneuvers can result in zonular dehiscence or mechanical endothelial damage. If the IOL is inspected under the microscope after it is midway into the nozzle, the surgeon can determine whether the leading haptic has failed to fold. If so, a fine caliber blunt instrument, such as a lacrimal cannula, can be used to position the leading haptic over the anterior face of the optic before it is injected into the anterior chamber (Figure 1). In this configuration, the optic unfolds within the bag before the haptics make contact with the equatorial capsule; thus, no force is transferred from the injection process (Figure 2). This is less traumatic than the surgeon pronating his or her wrist while injecting the IOL, when the haptic still engages the bag and the potential for wound distortion exists.
Figure 1. Use of a lacrimal cannula to place the leading haptic over the optic.
Figure 2. Deployment of the IOL with both haptics lying over the optic.
Maninder S. Bhogal, MB BS, Romesh I. Angunawela, MD, MRCOphth, Bruce D.S. Allan, MD, FRCOphth Online Video
J CATARACT REFRACT SURG - VOL 37, JANUARY 2011
CORRESPONDENCE
209
REFERENCES 1. van Vreeswijk H. Safe and easy way to release sticking haptic of a single-piece AcrySof intraocular lens. J Cataract Refract Surg 2008; 34:1611 2. Dada T. Difficulties during insertion of the AcrySof single-piece IOL [letter]. J Cataract Refract Surg 2004; 30:2645 3. Brigham DW. Preventing the sticky IOL haptic [letter]. J Cataract Refract Surg 2009; 35:1324–1325
Triple-post lid speculum: Maximizing exposure for cataract surgery Reay H. Brown, MD, Mary G. Lynch, MD, Kristen L. Hovis Many of the most popular lid speculums used in cataract and refractive surgery are made from wire and support each lid at 2 points. This creates a square or rectangular area of exposure, although the eye and limbal tissues are circular. We have designed a speculum with a third supporting element on each side to lift the lid centrally. This triple-post configuration creates a slightly oval area of exposure that more closely follows the shape of the eye. We compared the surgical area exposed by the triple-post speculum and the area exposed by a conventional double-post speculum.
MATERIALS AND METHODS A Lieberman wire speculum (Storz Ophthalmics) was placed in the eye of 12 patients having cataract surgery. The speculum was opened as widely as possible using the opening mechanism. This speculum was removed, and a triple-post speculum (Rhein Medical, Inc.) was placed and opened maximally. Photographs were taken of the eye with each speculum in place (Figure 1). Exposure was determined by measuring the area of the largest circle that could be inscribed between the eyelids.A The normalized exposure values with the triple post were compared with those with the Lieberman speculum using a paired t test calculated with VassarStats.B The significance was evaluated at a Z 0.0001.
Results The mean area of the largest circle that could be fit inside the lids was 3197.5 mm2 G 766.5 (SD) with the Lieberman speculum and 4251.9 G 616.9 mm2 with the triple post, yielding a mean difference of 1054.4 G 452.3 mm2. Compared with the Lieberman speculum, the triple post increased the area by 32.97% (P!.0001). All eyes experienced increased exposure with the triple-post speculum.
Financial disclosure: Dr. Brown receives a royalty from the device described that is donated to a 501(c)3 nonprofit foundation.
Figure 1. Column A: Lieberman lid speculum. Column B: Triple-post lid speculum.
DISCUSSION There are many effective lid speculum configurations and draping systems. The most popular design is the double-post wire speculum. This study demonstrates that the triple-post design provided more exposure for cataract surgery than a conventional doublepost speculum. This is particularly important in smaller eyes, deep-set eyes, tight orbits, and other situations in which exposure is challenging and may compromise the surgeon’s ability to perform the surgery. The central post of the triple-post speculum also supports contact between the drape and the lashes and prevents eversion of the lashes into the field. The double-post design supports the lid at the 2 ends only. The lack of central support may allow the lashes to evert more easily from beneath the drape and permit bacteria from the lid and lashes to enter the surgical field and increase the risk for endophthalmitis.1,2 In one patient, the lashes everted into the field after the double-post speculum was placed. Insertion of the triple-post
J CATARACT REFRACT SURG - VOL 37, JANUARY 2011
CORRESPONDENCE
Haptic misfolding during aspheric IOL insertion
AcrySof intraocular lenses (IOLs) (Alcon, Inc.) are very popular. Several authors have described problems with the injection of this IOL using the Monarch cartridge system (Alcon, Inc.), including damage to the IOL on loading, entrapment of the trailing haptic within the cartridge, and sticking of the leading haptic to the optic.1–3 The AcrySert injection system (Alcon, Inc.) aims to resolve several of these problems. Despite using the AcrySert injector, we have found that the leading haptic has a tendency to “misfold” and position itself in a reverse configuration within the capsular bag. This situation can result in the optic rotating and potentially coming into contact with the endothelium or being inserted upside down. To compensate for misfolding, the surgeon must pronate his or her wrist, rotating the injector clockwise so the leading haptic unfolds in a reverse “S” within the capsular bag before rotating it counterclockwise; this allows the optic and trailing haptics to align correctly. These compensatory maneuvers are likely to increase the subjective difficulty of this stage of cataract surgery. When the pupil is poorly dilated and the capsulorhexis small, a misfolded leading haptic may not be recognized by a surgeon unaware of this problem. This can result in reversal or tilting of the optic within the
bag, causing a refractive surprise or lens-induced astigmatism. By systematically analyzing surgical videos, we have seen that the leading haptic has a tendency to fold in on itself incompletely as it travels forward within the nozzle of the cartridge and remains pointing straight along the barrel of the cartridge in approximately 40% of cases (Video, available at http://jcrsjournal.org). If no compensatory maneuvers are made, when the IOL is released into the capsular bag, the distal tip of the leading haptic engages the capsule and remains relatively fixed. As the remainder of the IOL is injected, the resultant force pushes on the haptic and is transferred forward into the capsule and zonules and backward toward the optic, causing the IOL to rotate clockwise around an axis perpendicular to the optic plane. The haptic usually remains misaligned following IOL insertion, and manual dialing/repositioning of the IOL is required. These maneuvers can result in zonular dehiscence or mechanical endothelial damage. If the IOL is inspected under the microscope after it is midway into the nozzle, the surgeon can determine whether the leading haptic has failed to fold. If so, a fine caliber blunt instrument, such as a lacrimal cannula, can be used to position the leading haptic over the anterior face of the optic before it is injected into the anterior chamber (Figure 1). In this configuration, the optic unfolds within the bag before the haptics make contact with the equatorial capsule; thus, no force is transferred from the injection process (Figure 2). This is less traumatic than the surgeon pronating his or her wrist while injecting the IOL, when the haptic still engages the bag and the potential for wound distortion exists.
Figure 1. Use of a lacrimal cannula to place the leading haptic over the optic.
Figure 2. Deployment of the IOL with both haptics lying over the optic.
Maninder S. Bhogal, MB BS, Romesh I. Angunawela, MD, MRCOphth, Bruce D.S. Allan, MD, FRCOphth Online Video
J CATARACT REFRACT SURG - VOL 37, JANUARY 2011
CORRESPONDENCE
209
REFERENCES 1. van Vreeswijk H. Safe and easy way to release sticking haptic of a single-piece AcrySof intraocular lens. J Cataract Refract Surg 2008; 34:1611 2. Dada T. Difficulties during insertion of the AcrySof single-piece IOL [letter]. J Cataract Refract Surg 2004; 30:2645 3. Brigham DW. Preventing the sticky IOL haptic [letter]. J Cataract Refract Surg 2009; 35:1324–1325
Triple-post lid speculum: Maximizing exposure for cataract surgery Reay H. Brown, MD, Mary G. Lynch, MD, Kristen L. Hovis Many of the most popular lid speculums used in cataract and refractive surgery are made from wire and support each lid at 2 points. This creates a square or rectangular area of exposure, although the eye and limbal tissues are circular. We have designed a speculum with a third supporting element on each side to lift the lid centrally. This triple-post configuration creates a slightly oval area of exposure that more closely follows the shape of the eye. We compared the surgical area exposed by the triple-post speculum and the area exposed by a conventional double-post speculum.
MATERIALS AND METHODS A Lieberman wire speculum (Storz Ophthalmics) was placed in the eye of 12 patients having cataract surgery. The speculum was opened as widely as possible using the opening mechanism. This speculum was removed, and a triple-post speculum (Rhein Medical, Inc.) was placed and opened maximally. Photographs were taken of the eye with each speculum in place (Figure 1). Exposure was determined by measuring the area of the largest circle that could be inscribed between the eyelids.A The normalized exposure values with the triple post were compared with those with the Lieberman speculum using a paired t test calculated with VassarStats.B The significance was evaluated at a Z 0.0001.
Results The mean area of the largest circle that could be fit inside the lids was 3197.5 mm2 G 766.5 (SD) with the Lieberman speculum and 4251.9 G 616.9 mm2 with the triple post, yielding a mean difference of 1054.4 G 452.3 mm2. Compared with the Lieberman speculum, the triple post increased the area by 32.97% (P!.0001). All eyes experienced increased exposure with the triple-post speculum.
Financial disclosure: Dr. Brown receives a royalty from the device described that is donated to a 501(c)3 nonprofit foundation.
Figure 1. Column A: Lieberman lid speculum. Column B: Triple-post lid speculum.
DISCUSSION There are many effective lid speculum configurations and draping systems. The most popular design is the double-post wire speculum. This study demonstrates that the triple-post design provided more exposure for cataract surgery than a conventional doublepost speculum. This is particularly important in smaller eyes, deep-set eyes, tight orbits, and other situations in which exposure is challenging and may compromise the surgeon’s ability to perform the surgery. The central post of the triple-post speculum also supports contact between the drape and the lashes and prevents eversion of the lashes into the field. The double-post design supports the lid at the 2 ends only. The lack of central support may allow the lashes to evert more easily from beneath the drape and permit bacteria from the lid and lashes to enter the surgical field and increase the risk for endophthalmitis.1,2 In one patient, the lashes everted into the field after the double-post speculum was placed. Insertion of the triple-post
J CATARACT REFRACT SURG - VOL 37, JANUARY 2011