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Endocapsular ring approach to the subluxed cataractous lens
techn
•
1
que s
Endocapsular ring approach to the subluxed cataractous lens Robert J. Cionni, M.D., Robert H. Osher, M.D.
ABSTRACT The surgical management of the cataract associated with extensive zonular dialysis presents a challenge for the anterior segment surgeon. In 1993, a poly(methyl methacrylate) endocapsular ring was introduced to stabilize the capsular bag. We describe the use of this endocapsular ring in phacoemulsification and intraocular lens (IOL) implantation in the capsular bag in four patients with extensive traumatic or congenital zonular dialysis. The endocapsular ring allows expansion and stabilization of the capsular bag to facilitate cortical aspiration and uncomplicated IOL implantation. With follow-up of 4 to 10 months, all IOLs have remained well centered and the patients have had excellent vision free of complications. Key Words: endocapsular ring, phacoemulsification, subluxed lens, zonular dialysis
The surgical management of the cataract associated with extensive zonular dialysis presents a challenge for the anterior segment surgeon. When more than four or five clock hours of zonules are missing, many surgeons prefer intracapsular cataract extraction with implantation of an anterior chamber or sutured posterior chamber intraocular lens (IOL). Several reports from German and Japanese surgeons have advocated the use of a poly(methyl methacrylate) (PMMA) endocapsular ring designed to facilitate phacoemulsification and IOL implantation in patients with zonular dialysis. We describe the use of an endocapsular ring in phacoemulsification and lens implantation into the capsular bag in four patients with extensive traumatic zonular dialysis.
SURGICAL TECHNIQUE Case 1
A 69-year-old man was struck in his left eye with a tennis ball, resulting in anterior and temporal subluxation of the lens associated with traumatic glaucoma. A YAG laser iridotomy was performed to prevent pupillary block. Glaucoma was controlled with pilo-
carpine 2%. His visual function deteriorated, and he became incapable of driving at night because of glare from oncoming headlights. Our initial examination nine months later disclosed a best corrected visual acuity of 20/40, decreasing to worse than 20/400 with glare testing. The pupil was slightly distorted because of a torn sphincter, and the lens was subluxed with complete loss of zonules between the clock hours of 3:30 and 11:30 (240 degrees) (Figure 1). There was no vitreous present through the dialysis, although pigment was layered on the intact anterior hyaloid face. The cup-to-disc ratio was 0.6 and the intraocular pressure (lOP), 25 mm Hg. The fellow eye was normal, with a visual acuity of 20/20 and lOP of 14 mm Hg. We discussed at length the available options, which included conservative observation, intracapsular lens extraction with contact lens wear, phacoemulsification with a sutured posterior chamber IOL, or a new technique of lens implantation following the use of an endocapsular ring. After explaining the rationale of the endocapsular ring, we obtained appropriate informed consent based on a protocol approved by our Investi-
Reprint requests to Robert J. Cionni, M.D., Cincinnati Eye Institute, 10494 Montgomery Road, Cincinnati, Ohio 45242. JCATARACTREFRACTSURG-VOL21, MAY 1995
245
Fig. 1. (Cionni) Preoperative dilated appearance showing extensive zonular dialysis. gational Review Board for phacoemulsification and capsular bag placement of an endocapsular ring and an IOL combined with a filtering procedure. Mter adequate retrobulbar anesthesia was attained, a three-planed scleral tunnel incision was made in the axis of intact zonules and sodium hyaluronate (Healon GV®) used to deepen and maintain the anterior chamber. Additional viscoelastic was placed over the area of zonular absence to prevent anterior prolapse of vitreous. A continuous tear, curvilinear capsulorhexis was begun at the 2 o'clock position, taking advantage of the intact zonules to provide countertraction. After the area of zonular absence was reached, the capsule was flipped onto itself and a 5.5 mm diameter capsularhexis completed despite the lack of countertraction. A second, side-port incision was made at the 3 o'clock position, allowing limited gentle hydrodissection with balanced salt solution injected through a 27-gauge cannula. Bimanual phacoemulsification was performed using a divide technique with low infusion, an aspiration rate of 25 cc per minute, and a vacuum of 10 mm Hg. Healon GV was used for viscodissection, freeing each half of the nucleus from the cortical bowl. Cortex was also dissected free from the peripheral capsular bag by injecting viscoelastic material directly into the subcapsular plane. A 12 mm diameter endocapsular ring was introduced into the eye with Kelman-McPherson forceps and a second manipulating spatula to guide the device into the capsular bag (Figure 2). The capsular bag expanded and tautened, providing enough countertraction to allow complete cortical aspiration and even vacuuming of the posterior capsule (Figure 3). Healon GV was injected to open the capsular bag and a single-piece PMMA lens (13.75 mm diameter, 246
Fig. 2. (Cionni) Placement of endocapsular ring into capsular bag. The cortex remains adhered to the central posterior capsule.
Fig. 3. (Cionni) An endocapsular ring in place with expansion of the capsular bag. The cortex is adhered to the central posterior capsule.
6 mm optic) implanted, rotating one haptic into the area of zonular support (Figure 4). The IOL appeared well-centered, and an intracameral miotic was injected to constrict the pupil. The Healon GV was removed with a miniature irrigation/aspiration handpiece and the filtering procedure completed without difficulty using mitomycin with a releasable suture technique (J. Cohen, "Releasable Sutures," Audio Visual Journal of Cataract and Implant Surgery, 1992, vol. 8, #1). The postoperative course was uneventful, and the patient attained a visual acuity of 20/20 with a refractive error of -1.00 +0.75 X 175. The releasable suture was removed on the fifth postoperative day, and
J CATARACT REFRACT SURG-VOL 21, MAY 1995
Fig. 4.
(Cionni) Placement of IOL into expanded capsular bag.
Fig. 5.
(Cionni) One month after surgery, dilation shows mild, asymptomatic decentration.
lOP remained in the teens with a functioning filtering bleb. Four months after surgery, the IOL was slightly decentered yet stable and the patient asymptomatic (Figure 5).
Case 2
A 50-year-old woman was referred with bilateral subluxed crystalline lenses. Although the family history was strongly positive for this disorder, extensive medical evaluation failed to disclose an underlying etiology. The zonules were partially absent between 7 o'clock and 12 o'clock in the more severely affected right eye, and those that were present appeared stretched or elongated. Best corrected visual acuity was reduced to 20/200, consistent with dense white
nuclear sclerosis. A hyperopic refractive error was associated with a short axial length of 20.75 mm, while keratotomy and corneal topography confirmed 3.62 diopters (D) of with-the-rule astigmatism. Other positive findings included phakodonesis. The lens in the fellow eye was clear, and the zonular defect was limited to two clock hours with an associated lenticular coloboma. Surgery was performed using retrobulbar anesthesia and preoperative mannitol to dehydrate the vitreous body. The steep meridia were identified with an Osher keratoscope and the amount of cylinder confirmed with a Hyde astigmatic ruler. A scleral tunnel incision was dissected forward with a diamond knife, and the anterior chamber was entered through the clear cornea. Sodium chondroitin sulfatesodium hyaluronate (Viscoat®) was injected over the defective zonules and the remainder of the chamber filled with Healon GV. A 3.5 mm diameter minicapsulorhexis was made in the midperiphery of the anterior capsule, and limited hydrodissection partially loosened the nucleus within the capsular bag. A Kelman curved 30 degree tip was placed through the anterior capsular opening and an endocapsular phacoemulsification performed using a low aspiration rate of 25 cc per minute, a vacuum of 10 mm Hg, and low flow infusion. The hard nucleus required viscodissection to facilitate separation from the cortex while the vacuum was increased to 25 mm Hg. The cortical removal also required the injection of Healon GV for viscocleavage of the cortex from the loose capsular bag. The chamber and capsular bag were refilled with Healon, and a 14.5 mm diameter capsular ring was inserted through the capsulorhexis, resulting in expansion and centration of the bag. The posterior capsule was vacuumed and the small opening in the anterior capsulorhexis enlarged to allow implantation of a 29 D, single-piece, biconvex PMMA IOL with a 13.75 mm overall diameter and 6 mm optic (model 73 UV, Storz, St. Louis, MO). The lens was oriented horizontally and appeared well centered within the capsular bag; this was reconfirmed after instillation of an intracameral miotic. The viscoelastic was removed, and a watertight closure of the incision was attained. Three relaxing 690 J.Lm deep corneal incisions were placed under keratoscopic control around a 7.5 mm and an 8.0 mm optical zone. The patient attained a visual acuity of 20/50, with a refractive error of + 1.50 + 1.25 X 25. Nine months after surgery, the lens remained centered and the patient said her sight had never been better.
Case 3
A 69-year-old male with a long history of chronic open-angle glaucoma using timolol maleate (Timoptic®) 0.5% twice a day and pilocarpine 1% three times a day was referred for combined cataract and filtering
JCATARACTREFRACTSURG-VOL21, MAY 1995
247
surgery. There was no reported history of trauma. The patient's preoperative visual acuity was reduced to hand motion in the right eye and 20/50 in the left. Intraocular pressure was 24 mm Hg and 18 mm Hg, respectively. Slitlamp evaluation showed significant atrophy of each pupillary ruff and dense bilateral nuclear sclerotic cataract formation without evidence of pseudoexfoliation or phakodonesis. The view of the fundus was compromised by poor pupillary dilation and the dense nature of the cataracts. The cup-to-disc ratio was approximately 0.9 in both eyes, consistent with significant visual field loss. Following adequate retrobulbar anesthesia, a capsulorhexis was initiated, but it became obvious that the crystalline lens was extremely loose due to weak or missing zonules. The capsulorhexis was completed and bimanual phacoemulsification of the nucleus performed using a Kelman tip and a nucleofractis technique. As phacoemulsification of the nucleus was completed, a large (approximately 180 degree) temporal zonular dialysis with minimal vitreous prolapse was observed. A "dry" anterior vitrectomy was performed using Healon to maintain the anterior chamber. Healon was then used to reinflate the capsular bag, and the capsula-zonular anatomy was evaluated by retracting the iris with a blunt instrument to allow direct visualization. No posterior capsular tears or other areas of zonular dialysis were identified. The endocapsular ring was inserted into the capsular bag, which completely expanded and stabilized so that automated cortical aspiration and capsule vacuuming could be performed. A one-piece PMMA IOL with a 6 mm optic was placed in the capsular bag, and it centered spontaneously. The viscoelastic was removed. Acetylcholine was instilled, and the filtering procedure using releasable sutures was completed. The patient attained a visual acuity of finger counting, which is consistent with his glaucomatous optic nerve damage. Seven months after surgery, lOP was well controlled (18 mm Hg without medications) and the IOL remained well centered.
Case 4
A 74-year-old female with a history of blunt trauma to the right eye many years earlier developed a significant nuclear sclerotic and posterior subcapsular cataract, resulting in a visual acuity of 20/400. She had an early asymptomatic cataract in her fellow eye. The preoperative examination failed to disclose phakodonesis. She had phacoemulsification by another surgeon, who observed loose nasal zonules at the time of surgery. A continuous anterior capsulorhexis was accomplished, and the surgeon attempted to place a silicone plate IOL into the capsular bag. On the first postoperative day, the patient's visual acuity was 20/50, yet the IOL showed marked nasal dislocation. Examination revealed that the IOL was within the ciliary sulcus, with the nasal haptic pro248
lapsed through a large zonular dialysis. The patient was taken back to the operating room, where two stab incisions were placed at the 1 o'clock and 10 o'clock positions. After Healon was injected into the anterior chamber, a Sinskey hook was used to reposition the IOL in the capsular bag. Despite in-the-bag placement, the IOL failed to center in any axis of rotation. The zonular dialysis extended between the 1 o'clock and 5 o'clock meridia. The patient agreed to implantation of an endocapsular ring, which was introduced through the 1 o'clock stab incision and guided into the capsular bag. Once the ring was completely within the capsular bag, the lens spontaneously centered and the viscoelastic material was removed. Visual acuity improved to 20/30, and four months after surgery the IOL was well centered.
DISCUSSION In May 1993, Ulrich Legler, M.D., and coauthors introduced a PMMA endocapsular ring designed to stabilize the capsular bag ("The Capsular Ring: A New Device for Complicated Cataract Surgery," film presented at the 3rd American-International Congress on Cataract, IOL and Refractive Surgery, Seattle, May 1993). At the same meeting, Tsutomu Hara, M.D., and coauthors presented a film on a silicone endocapsular ring ("Equator Ring to Obtain Complete Circular Contour of the Capsular Bag Equator and to Prevent Postoperative Posterior Capsule Opacification"). These rings offer the surgeon another option for managing the subluxed or "loose" crystalline lens by providing a means to expand and stabilize the capsular bag for support of an IOL. However, surgeons considering the use of this ring must be capable of performing capsulorhexis and phacoemulsification of a cataract with loose or missing zonules. Significant zonular dialysis makes phacoemulsification, cortical aspiration, and lens implantation difficult, even in the most experienced hands. The use of viscoelastic material to retard vitreous prolapse and assist in viscodissection and manipulation of the nucleus and cortex has been extremely helpful (R. Osher, M.D., "Textbook of Viscosurgery," 1993, video, vol. 1). We have found that phacoemulsification can be safely performed using low vacuum, low aspiration, and low infusion. Implantation of an endocapsular ring results in expansion and stabilization of the capsular bag. The tautness of the bag provides countertraction that may facilitate cortical aspiration. Although we advocate the use of a single-piece, larger optic, PMMA lens, debate remains regarding the best axis for haptic placement in patients with moderate degrees of zonular dialysis. In each case presented here, one haptic was positioned into an area of zonular absence due to the extensive amount of dialysis present. Regardless of haptic place-
J CATARACf REFRACT SURG-VOL 21, MAY 1995
ment, it is important to evaluate IOL stability by performing a "bounce-back" test. If deliberate decentration-release fails to result in spontaneous recentration, the lens should be reoriented and reevaluated. If recentration fails to occur in all axes of placement, at least one haptic should be sutured into position. A short-acting intracameral miotic should be instilled to confirm centration near the conclusion of the procedure. Mild zonular loss can be managed with conventional phacoemulsification and implantation techniques, while extremely loose cataracts may require an intracapsular method. 1 The cases presented here all had large areas of zonular dialysis that were stable enough for careful, gentle phacoemulsification yet might have resulted in retained cortex and the need for scleral fixation of the IOL had the endocapsular ring
not been used. In each case, informed consent based on a protocol approved by our Investigational Review Board was obtained from the patient before implantation of the endocapsular ring. Although the patient with the most extensive zonular loss was doing well 10 months after surgery, further follow-up is necessary to evaluate for late decentration, either spontaneous or secondary to some degree of trauma. In these eyes having a more extensive zonular dialysis, the endocapsular ring has been a useful device and represents a significant advance in our surgical technique.
REFERENCE 1. Cionni R, Osher R. Complications of phacoemulsification surgery. In: Weinstock F, ed, Management and Care of the Cataract Patient. Cambridge, MA, Blackwell Scientific Publications, 1993; 209-210
J CATARACT REFRACT SURG-VOL 21, MAY 1995
249
•
1
que s
Endocapsular ring approach to the subluxed cataractous lens Robert J. Cionni, M.D., Robert H. Osher, M.D.
ABSTRACT The surgical management of the cataract associated with extensive zonular dialysis presents a challenge for the anterior segment surgeon. In 1993, a poly(methyl methacrylate) endocapsular ring was introduced to stabilize the capsular bag. We describe the use of this endocapsular ring in phacoemulsification and intraocular lens (IOL) implantation in the capsular bag in four patients with extensive traumatic or congenital zonular dialysis. The endocapsular ring allows expansion and stabilization of the capsular bag to facilitate cortical aspiration and uncomplicated IOL implantation. With follow-up of 4 to 10 months, all IOLs have remained well centered and the patients have had excellent vision free of complications. Key Words: endocapsular ring, phacoemulsification, subluxed lens, zonular dialysis
The surgical management of the cataract associated with extensive zonular dialysis presents a challenge for the anterior segment surgeon. When more than four or five clock hours of zonules are missing, many surgeons prefer intracapsular cataract extraction with implantation of an anterior chamber or sutured posterior chamber intraocular lens (IOL). Several reports from German and Japanese surgeons have advocated the use of a poly(methyl methacrylate) (PMMA) endocapsular ring designed to facilitate phacoemulsification and IOL implantation in patients with zonular dialysis. We describe the use of an endocapsular ring in phacoemulsification and lens implantation into the capsular bag in four patients with extensive traumatic zonular dialysis.
SURGICAL TECHNIQUE Case 1
A 69-year-old man was struck in his left eye with a tennis ball, resulting in anterior and temporal subluxation of the lens associated with traumatic glaucoma. A YAG laser iridotomy was performed to prevent pupillary block. Glaucoma was controlled with pilo-
carpine 2%. His visual function deteriorated, and he became incapable of driving at night because of glare from oncoming headlights. Our initial examination nine months later disclosed a best corrected visual acuity of 20/40, decreasing to worse than 20/400 with glare testing. The pupil was slightly distorted because of a torn sphincter, and the lens was subluxed with complete loss of zonules between the clock hours of 3:30 and 11:30 (240 degrees) (Figure 1). There was no vitreous present through the dialysis, although pigment was layered on the intact anterior hyaloid face. The cup-to-disc ratio was 0.6 and the intraocular pressure (lOP), 25 mm Hg. The fellow eye was normal, with a visual acuity of 20/20 and lOP of 14 mm Hg. We discussed at length the available options, which included conservative observation, intracapsular lens extraction with contact lens wear, phacoemulsification with a sutured posterior chamber IOL, or a new technique of lens implantation following the use of an endocapsular ring. After explaining the rationale of the endocapsular ring, we obtained appropriate informed consent based on a protocol approved by our Investi-
Reprint requests to Robert J. Cionni, M.D., Cincinnati Eye Institute, 10494 Montgomery Road, Cincinnati, Ohio 45242. JCATARACTREFRACTSURG-VOL21, MAY 1995
245
Fig. 1. (Cionni) Preoperative dilated appearance showing extensive zonular dialysis. gational Review Board for phacoemulsification and capsular bag placement of an endocapsular ring and an IOL combined with a filtering procedure. Mter adequate retrobulbar anesthesia was attained, a three-planed scleral tunnel incision was made in the axis of intact zonules and sodium hyaluronate (Healon GV®) used to deepen and maintain the anterior chamber. Additional viscoelastic was placed over the area of zonular absence to prevent anterior prolapse of vitreous. A continuous tear, curvilinear capsulorhexis was begun at the 2 o'clock position, taking advantage of the intact zonules to provide countertraction. After the area of zonular absence was reached, the capsule was flipped onto itself and a 5.5 mm diameter capsularhexis completed despite the lack of countertraction. A second, side-port incision was made at the 3 o'clock position, allowing limited gentle hydrodissection with balanced salt solution injected through a 27-gauge cannula. Bimanual phacoemulsification was performed using a divide technique with low infusion, an aspiration rate of 25 cc per minute, and a vacuum of 10 mm Hg. Healon GV was used for viscodissection, freeing each half of the nucleus from the cortical bowl. Cortex was also dissected free from the peripheral capsular bag by injecting viscoelastic material directly into the subcapsular plane. A 12 mm diameter endocapsular ring was introduced into the eye with Kelman-McPherson forceps and a second manipulating spatula to guide the device into the capsular bag (Figure 2). The capsular bag expanded and tautened, providing enough countertraction to allow complete cortical aspiration and even vacuuming of the posterior capsule (Figure 3). Healon GV was injected to open the capsular bag and a single-piece PMMA lens (13.75 mm diameter, 246
Fig. 2. (Cionni) Placement of endocapsular ring into capsular bag. The cortex remains adhered to the central posterior capsule.
Fig. 3. (Cionni) An endocapsular ring in place with expansion of the capsular bag. The cortex is adhered to the central posterior capsule.
6 mm optic) implanted, rotating one haptic into the area of zonular support (Figure 4). The IOL appeared well-centered, and an intracameral miotic was injected to constrict the pupil. The Healon GV was removed with a miniature irrigation/aspiration handpiece and the filtering procedure completed without difficulty using mitomycin with a releasable suture technique (J. Cohen, "Releasable Sutures," Audio Visual Journal of Cataract and Implant Surgery, 1992, vol. 8, #1). The postoperative course was uneventful, and the patient attained a visual acuity of 20/20 with a refractive error of -1.00 +0.75 X 175. The releasable suture was removed on the fifth postoperative day, and
J CATARACT REFRACT SURG-VOL 21, MAY 1995
Fig. 4.
(Cionni) Placement of IOL into expanded capsular bag.
Fig. 5.
(Cionni) One month after surgery, dilation shows mild, asymptomatic decentration.
lOP remained in the teens with a functioning filtering bleb. Four months after surgery, the IOL was slightly decentered yet stable and the patient asymptomatic (Figure 5).
Case 2
A 50-year-old woman was referred with bilateral subluxed crystalline lenses. Although the family history was strongly positive for this disorder, extensive medical evaluation failed to disclose an underlying etiology. The zonules were partially absent between 7 o'clock and 12 o'clock in the more severely affected right eye, and those that were present appeared stretched or elongated. Best corrected visual acuity was reduced to 20/200, consistent with dense white
nuclear sclerosis. A hyperopic refractive error was associated with a short axial length of 20.75 mm, while keratotomy and corneal topography confirmed 3.62 diopters (D) of with-the-rule astigmatism. Other positive findings included phakodonesis. The lens in the fellow eye was clear, and the zonular defect was limited to two clock hours with an associated lenticular coloboma. Surgery was performed using retrobulbar anesthesia and preoperative mannitol to dehydrate the vitreous body. The steep meridia were identified with an Osher keratoscope and the amount of cylinder confirmed with a Hyde astigmatic ruler. A scleral tunnel incision was dissected forward with a diamond knife, and the anterior chamber was entered through the clear cornea. Sodium chondroitin sulfatesodium hyaluronate (Viscoat®) was injected over the defective zonules and the remainder of the chamber filled with Healon GV. A 3.5 mm diameter minicapsulorhexis was made in the midperiphery of the anterior capsule, and limited hydrodissection partially loosened the nucleus within the capsular bag. A Kelman curved 30 degree tip was placed through the anterior capsular opening and an endocapsular phacoemulsification performed using a low aspiration rate of 25 cc per minute, a vacuum of 10 mm Hg, and low flow infusion. The hard nucleus required viscodissection to facilitate separation from the cortex while the vacuum was increased to 25 mm Hg. The cortical removal also required the injection of Healon GV for viscocleavage of the cortex from the loose capsular bag. The chamber and capsular bag were refilled with Healon, and a 14.5 mm diameter capsular ring was inserted through the capsulorhexis, resulting in expansion and centration of the bag. The posterior capsule was vacuumed and the small opening in the anterior capsulorhexis enlarged to allow implantation of a 29 D, single-piece, biconvex PMMA IOL with a 13.75 mm overall diameter and 6 mm optic (model 73 UV, Storz, St. Louis, MO). The lens was oriented horizontally and appeared well centered within the capsular bag; this was reconfirmed after instillation of an intracameral miotic. The viscoelastic was removed, and a watertight closure of the incision was attained. Three relaxing 690 J.Lm deep corneal incisions were placed under keratoscopic control around a 7.5 mm and an 8.0 mm optical zone. The patient attained a visual acuity of 20/50, with a refractive error of + 1.50 + 1.25 X 25. Nine months after surgery, the lens remained centered and the patient said her sight had never been better.
Case 3
A 69-year-old male with a long history of chronic open-angle glaucoma using timolol maleate (Timoptic®) 0.5% twice a day and pilocarpine 1% three times a day was referred for combined cataract and filtering
JCATARACTREFRACTSURG-VOL21, MAY 1995
247
surgery. There was no reported history of trauma. The patient's preoperative visual acuity was reduced to hand motion in the right eye and 20/50 in the left. Intraocular pressure was 24 mm Hg and 18 mm Hg, respectively. Slitlamp evaluation showed significant atrophy of each pupillary ruff and dense bilateral nuclear sclerotic cataract formation without evidence of pseudoexfoliation or phakodonesis. The view of the fundus was compromised by poor pupillary dilation and the dense nature of the cataracts. The cup-to-disc ratio was approximately 0.9 in both eyes, consistent with significant visual field loss. Following adequate retrobulbar anesthesia, a capsulorhexis was initiated, but it became obvious that the crystalline lens was extremely loose due to weak or missing zonules. The capsulorhexis was completed and bimanual phacoemulsification of the nucleus performed using a Kelman tip and a nucleofractis technique. As phacoemulsification of the nucleus was completed, a large (approximately 180 degree) temporal zonular dialysis with minimal vitreous prolapse was observed. A "dry" anterior vitrectomy was performed using Healon to maintain the anterior chamber. Healon was then used to reinflate the capsular bag, and the capsula-zonular anatomy was evaluated by retracting the iris with a blunt instrument to allow direct visualization. No posterior capsular tears or other areas of zonular dialysis were identified. The endocapsular ring was inserted into the capsular bag, which completely expanded and stabilized so that automated cortical aspiration and capsule vacuuming could be performed. A one-piece PMMA IOL with a 6 mm optic was placed in the capsular bag, and it centered spontaneously. The viscoelastic was removed. Acetylcholine was instilled, and the filtering procedure using releasable sutures was completed. The patient attained a visual acuity of finger counting, which is consistent with his glaucomatous optic nerve damage. Seven months after surgery, lOP was well controlled (18 mm Hg without medications) and the IOL remained well centered.
Case 4
A 74-year-old female with a history of blunt trauma to the right eye many years earlier developed a significant nuclear sclerotic and posterior subcapsular cataract, resulting in a visual acuity of 20/400. She had an early asymptomatic cataract in her fellow eye. The preoperative examination failed to disclose phakodonesis. She had phacoemulsification by another surgeon, who observed loose nasal zonules at the time of surgery. A continuous anterior capsulorhexis was accomplished, and the surgeon attempted to place a silicone plate IOL into the capsular bag. On the first postoperative day, the patient's visual acuity was 20/50, yet the IOL showed marked nasal dislocation. Examination revealed that the IOL was within the ciliary sulcus, with the nasal haptic pro248
lapsed through a large zonular dialysis. The patient was taken back to the operating room, where two stab incisions were placed at the 1 o'clock and 10 o'clock positions. After Healon was injected into the anterior chamber, a Sinskey hook was used to reposition the IOL in the capsular bag. Despite in-the-bag placement, the IOL failed to center in any axis of rotation. The zonular dialysis extended between the 1 o'clock and 5 o'clock meridia. The patient agreed to implantation of an endocapsular ring, which was introduced through the 1 o'clock stab incision and guided into the capsular bag. Once the ring was completely within the capsular bag, the lens spontaneously centered and the viscoelastic material was removed. Visual acuity improved to 20/30, and four months after surgery the IOL was well centered.
DISCUSSION In May 1993, Ulrich Legler, M.D., and coauthors introduced a PMMA endocapsular ring designed to stabilize the capsular bag ("The Capsular Ring: A New Device for Complicated Cataract Surgery," film presented at the 3rd American-International Congress on Cataract, IOL and Refractive Surgery, Seattle, May 1993). At the same meeting, Tsutomu Hara, M.D., and coauthors presented a film on a silicone endocapsular ring ("Equator Ring to Obtain Complete Circular Contour of the Capsular Bag Equator and to Prevent Postoperative Posterior Capsule Opacification"). These rings offer the surgeon another option for managing the subluxed or "loose" crystalline lens by providing a means to expand and stabilize the capsular bag for support of an IOL. However, surgeons considering the use of this ring must be capable of performing capsulorhexis and phacoemulsification of a cataract with loose or missing zonules. Significant zonular dialysis makes phacoemulsification, cortical aspiration, and lens implantation difficult, even in the most experienced hands. The use of viscoelastic material to retard vitreous prolapse and assist in viscodissection and manipulation of the nucleus and cortex has been extremely helpful (R. Osher, M.D., "Textbook of Viscosurgery," 1993, video, vol. 1). We have found that phacoemulsification can be safely performed using low vacuum, low aspiration, and low infusion. Implantation of an endocapsular ring results in expansion and stabilization of the capsular bag. The tautness of the bag provides countertraction that may facilitate cortical aspiration. Although we advocate the use of a single-piece, larger optic, PMMA lens, debate remains regarding the best axis for haptic placement in patients with moderate degrees of zonular dialysis. In each case presented here, one haptic was positioned into an area of zonular absence due to the extensive amount of dialysis present. Regardless of haptic place-
J CATARACf REFRACT SURG-VOL 21, MAY 1995
ment, it is important to evaluate IOL stability by performing a "bounce-back" test. If deliberate decentration-release fails to result in spontaneous recentration, the lens should be reoriented and reevaluated. If recentration fails to occur in all axes of placement, at least one haptic should be sutured into position. A short-acting intracameral miotic should be instilled to confirm centration near the conclusion of the procedure. Mild zonular loss can be managed with conventional phacoemulsification and implantation techniques, while extremely loose cataracts may require an intracapsular method. 1 The cases presented here all had large areas of zonular dialysis that were stable enough for careful, gentle phacoemulsification yet might have resulted in retained cortex and the need for scleral fixation of the IOL had the endocapsular ring
not been used. In each case, informed consent based on a protocol approved by our Investigational Review Board was obtained from the patient before implantation of the endocapsular ring. Although the patient with the most extensive zonular loss was doing well 10 months after surgery, further follow-up is necessary to evaluate for late decentration, either spontaneous or secondary to some degree of trauma. In these eyes having a more extensive zonular dialysis, the endocapsular ring has been a useful device and represents a significant advance in our surgical technique.
REFERENCE 1. Cionni R, Osher R. Complications of phacoemulsification surgery. In: Weinstock F, ed, Management and Care of the Cataract Patient. Cambridge, MA, Blackwell Scientific Publications, 1993; 209-210
J CATARACT REFRACT SURG-VOL 21, MAY 1995
249