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Nucleus removal following circular capsulorhexis: Surface cortex aspiration
N udeus removal following circular capsulorhexis: Surface cortex aspiration Okihiro Nishi, M.D.
AB TRA T A t chnique for nucleu remo al follo\ in circular cap ulOl'he is i de cribed. ftcr a continuou. circulal" ap ulotom , oft urface cortex ulToundin the nucleus is a. pirated b an irl"i ation/aspiration de ice to eparate the nucleu ' from cortical material and reduce it diametel·. With phacoemul 'ification the epa rated nucleu i ' rotated within the cap ular ba and emul ifi d. With planned tracap ular cataract e t' raction the upper nucl u equator i brou ht out of th cap ulal' bag u in an i.... igatin cap ule retractor. The nucleus i then deli ered b imple expl'e ion 01' b a i hi deli el' cannula,
Ke
cases, instruments and notes
Word: 'ir ular cap: ul orh 'i ', irrigatin g capsul r tractor, nu ·1 u r moval, : urfac cort . a pi' ration
Many pathophysiological studies indicate the physiological advantage of capsular bag fixation of posterior chamber lenses. 1-4 The anterior capsulotomy is the most important step in implantation surgery to ensure capsular bag fixation. There are various kinds of anterior caps ulotomies for this purpose, such as D-shaped and curvilinear, in intercapsular surgery or circular capsulorhexis. The advantage of circular capsulorhexis 5 or continuous tear capsulotomy6 is that a circular configuration with a smooth, continuous edge lessens the likelihood of stress being concentrated on a specific area of the capsular margin, thus avoiding creation of a radial tear of the anterior capsule during the extracapsular cataract extraction (ECCE) procedure. This capsular bag integrity without a radial tear enables secure, permanent placement of the posterior chamber lens in the capsular bag. Reprint requests to Okihiro Nishi, M.D., Nishi Eye Hospital, 4-14-26, Nakamichi, Higashinari-ku, Osaka 537, Japan.
372
J CATARACT
REFRACT SURG- VOL 16, MAY 1990
In the conventional can-opener anterior capsulotomy, radial tears are created unavoidably during nucleus delivery or later in the procedure, since the anterior capsular margin is formed by continuous V-shaped edges subject to concentrated stress vectors. The tears act as unintentional relaxing incisions to secure safe and easy nucleus delivery at the expense of capsular integrity, which ultimately prevents predictable capsular bag fixation of a posterior chamber lens. The advantage of circular capsulorhexis with its stable anterior capsule margin, however, may present technical problems during nucleus removal in phacoemulsification and in planned ECCE. In phacoemulsification, access to the upper nucleus with the phacoemulsification tip is not possible. In planned ECCE, it is very difficult or impossible to deliver the nucleus through a small, round anterior capsule opening with a firm margin. This report
a
AnterIOr Capsule Marll.n I
b
c Fig. 2.
(Nishi) Side view of surface cortex aspiration before phacoemulsification. a, h. Aspiration in the lower part of the cortex. c. Aspiration in the upper part of the cortex.
describes a nucleus removal technique following circular capsulorhexis with phacoemulsification and with planned ECCE. c
Fig. 1.
d
(Nishi) Surface cortex aspiration. a. The cortex within the circular cut is first removed by aspiration. h. The irrigation/aspiration tip is inserted underneath the anterior capsule to move and aspirate the surface cortex near 6 o' clock. c. The lower two thirds of the cortex is aspirated. d. The upper one third of the surface cortex is removed.
J CATARACT REFRACT
SURGICAL TECHNIQUE
Surface Cortex Aspiration for Separating the Nucleus from Cortical Material
It is essential to separate the nucleus from cortical material before nucleus removal. Instead of using conventional hydrodissection I aspirate the surface cortex before phacoemulsification or planned ECCE SURG- VOL 16, MAY 1990
373
after circular capsulorhexis. The irrigation/aspiration tip is inserted into the anterior chamber and the cortex within the circular tear is first aspirated. Then the end of the tip is inserted beneath the anterior capsule. The aspirating port is directed downward so the thin surface layer of the cortex directly beneath the anterior capsule is engaged. Once the surface cortex is engaged, it is pulled and jogged to separate it from the nucleus as well as the anterior capsule undersurface and is then aspirated (Figures 1 and 2). This maneuver is begun at the lower two thirds of the circular cut. The surface cortex is removed as by an "ice cream scoop" maneuver at 12 o'clock (Figures 1d and 2c). After the surface cortex is pulled and aspirated, the nucleus is loosened from the cortex and moved to rest within the capsular bag.
nucleus. The nucleus is hydrodissected from the remaining cortex layers and its upper equator is brought over the anterior capsule into the anterior chamber (Figure 3). Now the nucleus can be expressed simply or removed by a Nishi irrigating cannula. Prior to the final procedure, sodium hyaluronate (Healon®) is injected between the cornea
Nucleus Removal in Phacoemulsification Since the nucleus is loosened from the cortex after surface cortex aspiration, it can be rotated in the capsular bag. The nucleus is emulsified within the capsular bag under the capsular edge. After the lower part of the nucleus has been removed, the remaining nucleus is rotated with the tip so the upper part is under the capsular space and is emulsified. After these rotating and emulsifying maneuvers, the nucleus becomes thin and discshaped with a small diameter. This residual nucleus disc is caught by the ultrasound tip and emulsified. Sometimes this maneuver is not feasible with a hard residual nucleus disc. In those cases, the tip with the bevel directed downward is engaged to the equatorial area of the disc with minimal ultrasound intensity. Once the tip opening is engaged and completely covered by the nucleus material, the nucleus is pulled up and toward the center using aspiration power and minimal ultrasound intensity and is then emulsified by increasing ultrasound intensity. This maneuver is performed repeatedly until finally the nucleus, now small, is emulsified. Nucleus Delivery in Planned Extracapsular Cataract Extraction After a circular capsulorhexis with a diameter of about 5 mm to 6 mm has been made, the surface cortex is aspirated as described. A corneal incision is made and is slightly elevated while an irrigating capsule retractor is inserted in the eye. This retractor is made of a 20-gauge needle, the top of which is flattened to about 2.4 mm and has a fine wire hook attached. 7 Some layers of remaining cortex around the hard nucleus (nucleus core) together with the anterior capsular margin are hooked with this retractor. The capsule margin is pulled away from the nucleus equator and irrigation is performed beneath the 374
J CATARACT REFRACT
a
b
c
d
Fig. 3.
(Nishi) Nucleus delivery following circular capsulorhexis in planned ECCE. a, h. Surface cortex aspiration for separating and reducing the nucleus. c, d. The upper nucleus equator is brought out of the bag and posterior hydrodissection using an irrigating capsule retractor is performed.
SURG-VOL 16, MAY 1990
Fig. 4.
(Nishi) A posterior chamber lens secure in the capsular bag three months after phacoemulsification following circular capsulorhexis. The optic diameter is 6 mm.
and nucleus to protect the corneal endothelium from friction with the rough nucleus surface.
RESULTS AND DISCUSSION I have performed this technique on more than 250 eyes. In every case the cortex on the nucleus extending to the equatorial zone was aspirated easily. The cortex at the nucleus equator was not always removed and the cortex beneath the nucleus was not removed at all. However, the nucleus was easily mobilized in every case and rotated within the capsular bag for all subsequent maneuvers. In addition, the irrigating solution, which invaded the region between the capsule and nucleus as in hydrodissection, eased nucleus mobilization. In elderly patients, the surface cprtex can generally be aspirated easily. In cataract patients under 50 years of age, the cortex is viscous which makes the aspiration difficult. However, in the soft cortex of young patients, the irrigation/aspiration tip can be inserted to the nucleus equator since the nucleus is small. Anterior capsule rupture did not occur during surface cortex aspiration even when the tip was initially inserted beneath the anterior capsule into the tight viscous space. This is attributed to the stable edge of the capsular opening following circular capsulorhexis. Since this aspirating technique is virtually the same as the cortex removal technique and is performed without coming into contact with the posterior capsule, there is no danger of capsule rupture . (Michael Blumenthal, M .D ., reports a similar technique. He aspirates surface cortex but within the capsular opening to separate the hard central nucleus from the epinucleus. "ECCE-Emphasis on J CATARACT REFRACT
Innovations in Capsulectomy, Nucleus Expression, Anterior Chamber Maintainer, Suction, Subconjunctival Injection;" video presented at the Symposium on Cataract, IOL and Refractive Surgery, Orlando, Florida, April 1987.) After the nucleus is separated by surface cortex aspiration, it is easily and safely emulsified within the capsular bag. Emulsifying the equatorial area of the remaining nucleus disc is most critical. Since the nucleus is now thin, the phaocemulsification tip can readily touch the capsule and rupture it. To emulsify the remaining thin nucleus disc safely it must be raised from the capsule. For this purpose the technique of engaging the tip to the disc with minimal ultrasound intensity is a safe and useful procedure. Since the ultrasound intensity is minimal, the aspiration power predominates the ultrasound force required to move the nucleus to the center of the bag. To engage the tip to the nucleus disc in this manner, linear control of ultrasound is essential. The capsular bag fixation obtained is excellent (Figure 4). Even· after this maneuver, however, it is still not possible to express the nucleus safely in planned ECCE. The upper nucleus equator must be brought out of the capsular bag. The described irrigating capsule retractor can achieve this successfully without tearing the anterior capsule in a radial direction since the nucleus is separated and its diameter is reduced by surface cortex aspiration. After irrigation, posterior nucleus separation that was achieved by surface cortex removal is complete. With these maneuvers, the nucleus is removed through the anterior capsule opening of about 5 mm diameter without tearing the capsule (Figure 5).
Fig. 5.
(N ishi) A posterior chamber lens secure in the capsular bag one month after planned ECCE following circular capsulorhexis. Note the anterior capsule opening of about 5 mm without radial tears through which the nucleus was removed using a surface aspiration technique and an irrigating capsule retractor.
SURC-VOL 16, MAY 1990
375
In some cases, when the circular cut is relatively small in diameter and the nucleus is relatively large, one radial tear occurs during the last maneuver when the upper nucleus is brought out of the bag. Therefore, it is preferable to perform the circular cut with a diameter of more than 5 mm in planned ECCE, even if the nucleus diameter is reduced by surface cortex aspiration. However, since only one tear ever occurs, the secure placement of the posterior chamber lens in the bag is not impaired. It is important to inject Healon to reduce the friction between the corneal endothelium and the nucleus, since the rough nucleus surface following surface cortex aspiration damages the endothelium. This surface cortex aspiration technique separates the nucleus from the cortical material easily and safely. It is an excellent alternative method to conventional hydrodissection and makes the lens smaller in diameter. The nucleus removal technique including surface cortex aspiration is a safe and secure procedure for removing the nucleus following circular capsulorhexis in phacoemulsification and in planned ECCE. REFERENCES 1. Apple DJ, Mamalis N, Loftfield K, et al. Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol1984; 29:1-54 2. Apple DJ, Reidy Googe JM, et al. A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses. Am Intra-Ocular Implant Soc J 1985; 11:44-63 3. Apple DJ, Park SB, Merkley KH, et al. Posterior chamber intraocular lenses in a series of75 autopsy eyes. Part I: Loop location. J Cataract Refract Surg 1986; 12:358-362 4. Miyake K, Asakura M, Kobayashi H. Effect of intraocular lens fixation on the blood-aqueous barrier. Am J Ophthalmol 1984; 98:451-455 5. Neuhann Th: Theorie und Operationstechnik der Kapsulorhexis. Klin Monatsbl Augenheilkd 1987; 190:542-545 6. Gimbel HV, Neuhann T. Development, advantages, and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990; 16:31-37 7. Nishi 0: Extracapsular cataract extraction with keyhole capsulorhexis and lens epithelial cell removal. J Cataract Refract Surg 1990; 16:249-252
n,
New cystotome for intercapsular cataract procedures Patrick W. Joyce, F.R.C.S. Liaquat Allarakhia, M. D.
AB TR T Intercap ular cataract extraction a ariation of e 'tracap ulal' cataract xll'action ( ) ha I'ec ntl b COIl'l popul3l' particulad in '!. urope and A ia. It i aining popularit in the United tate amon both phacoemul ification and planned E ur eon . The initial . teps in the intercap ular cap ul tom include either a linear or cur ilinear opening. To fa iJitate anterior cap ulotom for intel'cap ular sur er \! e de elop d a di po able 27- auge c toto me .. ith a speciall de igned cur ed configuration. Thi c totome al 0 facilitat cap ulotomie in d epet e e .. hich ma be difficult .. hen tandard c stotome ar u ed. The ne' c stotome ha a con entional be eled tip \! ith a 90-de ree bend and a main haft cur ed at a radiu ' of 14.5 mm. When attached to a ring thi c stotome allO\ s th urgeon a more comfol"tabl holdin po ition during the cap ulotom pl"Ocedure.
Ke
\Vord
ant rior 'apsulotoJllY, oi 'posabl > c),stotom' , Il\ lop te 'hniqll , e \tracapslllar catara ·t xtra -tion . int >rcap:ular ( ndo 'ap 'lIlar) catara of xtractiol1
Extracapsular cataract extraction has become the preferred method of removing the crystalline lens. Anterior capsulotomy is one of the essential steps during extracapsular procedures. Usually a large circular opening is made in the anterior capsule using a disposable or less frequently a reusable From the Manchester Royal Eye Hospital, Manchester, England (Joyce) and the Department of Research and Development, Visitec Company, Sarasota, Florida (Allarakhia). The authors have no proprietary or financial interest in the instrument described in this report. Reprint requests to Liaquat Allarakhia, M.D., 7575 Commerce Court, Sarasota, Florida 34243.
376
J CATARACT REFRACT
SURG- VOL 16, MAY 1990
AB TRA T A t chnique for nucleu remo al follo\ in circular cap ulOl'he is i de cribed. ftcr a continuou. circulal" ap ulotom , oft urface cortex ulToundin the nucleus is a. pirated b an irl"i ation/aspiration de ice to eparate the nucleu ' from cortical material and reduce it diametel·. With phacoemul 'ification the epa rated nucleu i ' rotated within the cap ular ba and emul ifi d. With planned tracap ular cataract e t' raction the upper nucl u equator i brou ht out of th cap ulal' bag u in an i.... igatin cap ule retractor. The nucleus i then deli ered b imple expl'e ion 01' b a i hi deli el' cannula,
Ke
cases, instruments and notes
Word: 'ir ular cap: ul orh 'i ', irrigatin g capsul r tractor, nu ·1 u r moval, : urfac cort . a pi' ration
Many pathophysiological studies indicate the physiological advantage of capsular bag fixation of posterior chamber lenses. 1-4 The anterior capsulotomy is the most important step in implantation surgery to ensure capsular bag fixation. There are various kinds of anterior caps ulotomies for this purpose, such as D-shaped and curvilinear, in intercapsular surgery or circular capsulorhexis. The advantage of circular capsulorhexis 5 or continuous tear capsulotomy6 is that a circular configuration with a smooth, continuous edge lessens the likelihood of stress being concentrated on a specific area of the capsular margin, thus avoiding creation of a radial tear of the anterior capsule during the extracapsular cataract extraction (ECCE) procedure. This capsular bag integrity without a radial tear enables secure, permanent placement of the posterior chamber lens in the capsular bag. Reprint requests to Okihiro Nishi, M.D., Nishi Eye Hospital, 4-14-26, Nakamichi, Higashinari-ku, Osaka 537, Japan.
372
J CATARACT
REFRACT SURG- VOL 16, MAY 1990
In the conventional can-opener anterior capsulotomy, radial tears are created unavoidably during nucleus delivery or later in the procedure, since the anterior capsular margin is formed by continuous V-shaped edges subject to concentrated stress vectors. The tears act as unintentional relaxing incisions to secure safe and easy nucleus delivery at the expense of capsular integrity, which ultimately prevents predictable capsular bag fixation of a posterior chamber lens. The advantage of circular capsulorhexis with its stable anterior capsule margin, however, may present technical problems during nucleus removal in phacoemulsification and in planned ECCE. In phacoemulsification, access to the upper nucleus with the phacoemulsification tip is not possible. In planned ECCE, it is very difficult or impossible to deliver the nucleus through a small, round anterior capsule opening with a firm margin. This report
a
AnterIOr Capsule Marll.n I
b
c Fig. 2.
(Nishi) Side view of surface cortex aspiration before phacoemulsification. a, h. Aspiration in the lower part of the cortex. c. Aspiration in the upper part of the cortex.
describes a nucleus removal technique following circular capsulorhexis with phacoemulsification and with planned ECCE. c
Fig. 1.
d
(Nishi) Surface cortex aspiration. a. The cortex within the circular cut is first removed by aspiration. h. The irrigation/aspiration tip is inserted underneath the anterior capsule to move and aspirate the surface cortex near 6 o' clock. c. The lower two thirds of the cortex is aspirated. d. The upper one third of the surface cortex is removed.
J CATARACT REFRACT
SURGICAL TECHNIQUE
Surface Cortex Aspiration for Separating the Nucleus from Cortical Material
It is essential to separate the nucleus from cortical material before nucleus removal. Instead of using conventional hydrodissection I aspirate the surface cortex before phacoemulsification or planned ECCE SURG- VOL 16, MAY 1990
373
after circular capsulorhexis. The irrigation/aspiration tip is inserted into the anterior chamber and the cortex within the circular tear is first aspirated. Then the end of the tip is inserted beneath the anterior capsule. The aspirating port is directed downward so the thin surface layer of the cortex directly beneath the anterior capsule is engaged. Once the surface cortex is engaged, it is pulled and jogged to separate it from the nucleus as well as the anterior capsule undersurface and is then aspirated (Figures 1 and 2). This maneuver is begun at the lower two thirds of the circular cut. The surface cortex is removed as by an "ice cream scoop" maneuver at 12 o'clock (Figures 1d and 2c). After the surface cortex is pulled and aspirated, the nucleus is loosened from the cortex and moved to rest within the capsular bag.
nucleus. The nucleus is hydrodissected from the remaining cortex layers and its upper equator is brought over the anterior capsule into the anterior chamber (Figure 3). Now the nucleus can be expressed simply or removed by a Nishi irrigating cannula. Prior to the final procedure, sodium hyaluronate (Healon®) is injected between the cornea
Nucleus Removal in Phacoemulsification Since the nucleus is loosened from the cortex after surface cortex aspiration, it can be rotated in the capsular bag. The nucleus is emulsified within the capsular bag under the capsular edge. After the lower part of the nucleus has been removed, the remaining nucleus is rotated with the tip so the upper part is under the capsular space and is emulsified. After these rotating and emulsifying maneuvers, the nucleus becomes thin and discshaped with a small diameter. This residual nucleus disc is caught by the ultrasound tip and emulsified. Sometimes this maneuver is not feasible with a hard residual nucleus disc. In those cases, the tip with the bevel directed downward is engaged to the equatorial area of the disc with minimal ultrasound intensity. Once the tip opening is engaged and completely covered by the nucleus material, the nucleus is pulled up and toward the center using aspiration power and minimal ultrasound intensity and is then emulsified by increasing ultrasound intensity. This maneuver is performed repeatedly until finally the nucleus, now small, is emulsified. Nucleus Delivery in Planned Extracapsular Cataract Extraction After a circular capsulorhexis with a diameter of about 5 mm to 6 mm has been made, the surface cortex is aspirated as described. A corneal incision is made and is slightly elevated while an irrigating capsule retractor is inserted in the eye. This retractor is made of a 20-gauge needle, the top of which is flattened to about 2.4 mm and has a fine wire hook attached. 7 Some layers of remaining cortex around the hard nucleus (nucleus core) together with the anterior capsular margin are hooked with this retractor. The capsule margin is pulled away from the nucleus equator and irrigation is performed beneath the 374
J CATARACT REFRACT
a
b
c
d
Fig. 3.
(Nishi) Nucleus delivery following circular capsulorhexis in planned ECCE. a, h. Surface cortex aspiration for separating and reducing the nucleus. c, d. The upper nucleus equator is brought out of the bag and posterior hydrodissection using an irrigating capsule retractor is performed.
SURG-VOL 16, MAY 1990
Fig. 4.
(Nishi) A posterior chamber lens secure in the capsular bag three months after phacoemulsification following circular capsulorhexis. The optic diameter is 6 mm.
and nucleus to protect the corneal endothelium from friction with the rough nucleus surface.
RESULTS AND DISCUSSION I have performed this technique on more than 250 eyes. In every case the cortex on the nucleus extending to the equatorial zone was aspirated easily. The cortex at the nucleus equator was not always removed and the cortex beneath the nucleus was not removed at all. However, the nucleus was easily mobilized in every case and rotated within the capsular bag for all subsequent maneuvers. In addition, the irrigating solution, which invaded the region between the capsule and nucleus as in hydrodissection, eased nucleus mobilization. In elderly patients, the surface cprtex can generally be aspirated easily. In cataract patients under 50 years of age, the cortex is viscous which makes the aspiration difficult. However, in the soft cortex of young patients, the irrigation/aspiration tip can be inserted to the nucleus equator since the nucleus is small. Anterior capsule rupture did not occur during surface cortex aspiration even when the tip was initially inserted beneath the anterior capsule into the tight viscous space. This is attributed to the stable edge of the capsular opening following circular capsulorhexis. Since this aspirating technique is virtually the same as the cortex removal technique and is performed without coming into contact with the posterior capsule, there is no danger of capsule rupture . (Michael Blumenthal, M .D ., reports a similar technique. He aspirates surface cortex but within the capsular opening to separate the hard central nucleus from the epinucleus. "ECCE-Emphasis on J CATARACT REFRACT
Innovations in Capsulectomy, Nucleus Expression, Anterior Chamber Maintainer, Suction, Subconjunctival Injection;" video presented at the Symposium on Cataract, IOL and Refractive Surgery, Orlando, Florida, April 1987.) After the nucleus is separated by surface cortex aspiration, it is easily and safely emulsified within the capsular bag. Emulsifying the equatorial area of the remaining nucleus disc is most critical. Since the nucleus is now thin, the phaocemulsification tip can readily touch the capsule and rupture it. To emulsify the remaining thin nucleus disc safely it must be raised from the capsule. For this purpose the technique of engaging the tip to the disc with minimal ultrasound intensity is a safe and useful procedure. Since the ultrasound intensity is minimal, the aspiration power predominates the ultrasound force required to move the nucleus to the center of the bag. To engage the tip to the nucleus disc in this manner, linear control of ultrasound is essential. The capsular bag fixation obtained is excellent (Figure 4). Even· after this maneuver, however, it is still not possible to express the nucleus safely in planned ECCE. The upper nucleus equator must be brought out of the capsular bag. The described irrigating capsule retractor can achieve this successfully without tearing the anterior capsule in a radial direction since the nucleus is separated and its diameter is reduced by surface cortex aspiration. After irrigation, posterior nucleus separation that was achieved by surface cortex removal is complete. With these maneuvers, the nucleus is removed through the anterior capsule opening of about 5 mm diameter without tearing the capsule (Figure 5).
Fig. 5.
(N ishi) A posterior chamber lens secure in the capsular bag one month after planned ECCE following circular capsulorhexis. Note the anterior capsule opening of about 5 mm without radial tears through which the nucleus was removed using a surface aspiration technique and an irrigating capsule retractor.
SURC-VOL 16, MAY 1990
375
In some cases, when the circular cut is relatively small in diameter and the nucleus is relatively large, one radial tear occurs during the last maneuver when the upper nucleus is brought out of the bag. Therefore, it is preferable to perform the circular cut with a diameter of more than 5 mm in planned ECCE, even if the nucleus diameter is reduced by surface cortex aspiration. However, since only one tear ever occurs, the secure placement of the posterior chamber lens in the bag is not impaired. It is important to inject Healon to reduce the friction between the corneal endothelium and the nucleus, since the rough nucleus surface following surface cortex aspiration damages the endothelium. This surface cortex aspiration technique separates the nucleus from the cortical material easily and safely. It is an excellent alternative method to conventional hydrodissection and makes the lens smaller in diameter. The nucleus removal technique including surface cortex aspiration is a safe and secure procedure for removing the nucleus following circular capsulorhexis in phacoemulsification and in planned ECCE. REFERENCES 1. Apple DJ, Mamalis N, Loftfield K, et al. Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol1984; 29:1-54 2. Apple DJ, Reidy Googe JM, et al. A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses. Am Intra-Ocular Implant Soc J 1985; 11:44-63 3. Apple DJ, Park SB, Merkley KH, et al. Posterior chamber intraocular lenses in a series of75 autopsy eyes. Part I: Loop location. J Cataract Refract Surg 1986; 12:358-362 4. Miyake K, Asakura M, Kobayashi H. Effect of intraocular lens fixation on the blood-aqueous barrier. Am J Ophthalmol 1984; 98:451-455 5. Neuhann Th: Theorie und Operationstechnik der Kapsulorhexis. Klin Monatsbl Augenheilkd 1987; 190:542-545 6. Gimbel HV, Neuhann T. Development, advantages, and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990; 16:31-37 7. Nishi 0: Extracapsular cataract extraction with keyhole capsulorhexis and lens epithelial cell removal. J Cataract Refract Surg 1990; 16:249-252
n,
New cystotome for intercapsular cataract procedures Patrick W. Joyce, F.R.C.S. Liaquat Allarakhia, M. D.
AB TR T Intercap ular cataract extraction a ariation of e 'tracap ulal' cataract xll'action ( ) ha I'ec ntl b COIl'l popul3l' particulad in '!. urope and A ia. It i aining popularit in the United tate amon both phacoemul ification and planned E ur eon . The initial . teps in the intercap ular cap ul tom include either a linear or cur ilinear opening. To fa iJitate anterior cap ulotom for intel'cap ular sur er \! e de elop d a di po able 27- auge c toto me .. ith a speciall de igned cur ed configuration. Thi c totome al 0 facilitat cap ulotomie in d epet e e .. hich ma be difficult .. hen tandard c stotome ar u ed. The ne' c stotome ha a con entional be eled tip \! ith a 90-de ree bend and a main haft cur ed at a radiu ' of 14.5 mm. When attached to a ring thi c stotome allO\ s th urgeon a more comfol"tabl holdin po ition during the cap ulotom pl"Ocedure.
Ke
\Vord
ant rior 'apsulotoJllY, oi 'posabl > c),stotom' , Il\ lop te 'hniqll , e \tracapslllar catara ·t xtra -tion . int >rcap:ular ( ndo 'ap 'lIlar) catara of xtractiol1
Extracapsular cataract extraction has become the preferred method of removing the crystalline lens. Anterior capsulotomy is one of the essential steps during extracapsular procedures. Usually a large circular opening is made in the anterior capsule using a disposable or less frequently a reusable From the Manchester Royal Eye Hospital, Manchester, England (Joyce) and the Department of Research and Development, Visitec Company, Sarasota, Florida (Allarakhia). The authors have no proprietary or financial interest in the instrument described in this report. Reprint requests to Liaquat Allarakhia, M.D., 7575 Commerce Court, Sarasota, Florida 34243.
376
J CATARACT REFRACT
SURG- VOL 16, MAY 1990