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A Posterior Chamber IOL in the Absence of a Capsular Barrier*
A Posterior Chamber IOL in the Absence of a Capsular Barrier* c. MAGGI and R. MAGGI Via Latina 8, 00 179 Rome, Italy
An IOL with direct attachment to the sclera has been implanted in the absence of the posterior capsule in a total of 114 cases: as primary implant during ICCE in 93 eyes, and as secondary implant in 21 eyes. Vitrectomy was not necessary in any patient. No part of the haptics or non-absorbable sutures were left on the surface of the sclera. The haptics were completely embedded in the scleral thickness without sutures and were anchored by their terminal knob. Keywords: Suspensory fixation; Intracapsular extraction; Hyperbaric compression of vitreous implant fixation, which allows the implant to be suspended from the sclera, instead of being wedged In conventional cataract surgery, posterior chamber across the anterior segment, and secondly a special implantation with a preserved capsular barrier is operating table which allows the hyperbaric comconsidered mandatory. However, in a minority of pression of the surgically opened eye throughout surcases this technique is not practicable, because either gery [16]. The implant has a central optic in PMMA, there is an indication for intracapsular extraction preferably of 6.5 or 7 mm diameter, to which three (recurrent uveitis [1], retinal detachment), for len- armed prolene sutures 5 cm in length are attached at sectomy (congenital cataract [2], or dislocation of the 120° intervals (Fig. 1). One thread has a straight lens [3, 4]), or because there is weakness or absence, needle which is inserted into the fenestrated cannula of the posterior capsule (exfoliation syndrome [5, 6], of a special needle-holder (Fig. 2). During insertion, because the threads are attached previous intracapsular extraction, some eye trauto the optic at intervals of 120°, two of them can be mas, peroperative rupture of the posterior capsule). passed in and out ofthe eye through the 160° corneal In all the above cases, an anterior chamber implant opening using a needle-holder. The third needs a [7, 8], or secondary corneal surgery (epikeratoseparate scleral incision at 6 o'clock on the opposite phakia, keratomileusis) are the only methods of surside of the limbus. This manreuvre has been simpligery considered. However, because of a growing fied in the present technique. reluctance to use an anterior chamber implant, various techniques of the implantation ofa conventional posterior chamber lens in the absence of a capsular SURGICAL TECHNIQUE barrier have recently been proposed [9-15]. In all these methods, one or two of the haptics of the Primary implantation implant are fixed to the sclera or iris with 10/0 sutures. Three scleral pockets are made at 2,6 and 10 o'clock We proposed a technique that uses a posterior (Fig. 3), and the limbal incision performed (Fig. 3a). chamber implant in either secondary implantation in The first needle is inserted in a reverse position into a the absence of the capsular barrier, or in a planned fenestrated cannula which allows the free passage of intracapsular extraction. the prolene thread (Fig. 2). The cannula with its armed prolene thread is then passed through the pupil and brought into contact with the inner side of MATERIALS AND METHOD the iris root at 6 o'clock (Fig. 3b). A gentle inverse To achieve these results two innovations have been indentation with the smooth end of the cannula locanecessary, firstly the use of a different kind of lizes the correct position inside the 6 o'clock scleral pocket at 2.5 mm from the limbus. The needle is now Read at the EIIC Congress, Copenhagen, 1988. INTRODUCTION
0955-3681/91/020139 + 06 $03.00/0 © 1991 Bailliere Tindall
Eur J Implant Ref Surg, Vol 3, June 1991
140
C. Maggi, R. Maggi
Fig.l The lens with three armed 0.1 mm prolene haptic threads and special needle-holder. Two of these have a 7 mm curved corneal needle attached, and the third thread is armed with a 7 mm straight corneal needle
Fig. 2 Enlarged view showing the straight needle half-way into its final place in the cannula before use
,.J
'"
,/
~~/ <0'
9/ . . "'-Qy
- . "' ~g
~.
/'
I
,
'
"
L
Fig. 3 Main steps of surgery in primary implantation
Eur J Implant Ref Surg. Vol 3. June 1991
A Posterior Chamber IOL in the Absence of a Capsular Barrier
ejected through the eye wall, piercing the sclera. The prolene thread is pulled out of the eye, drawing the lens in to be laid in the lowest possible position between the iris and the crystalline lens (Fig. 3c). With the lens already inside the eye, the other two needles are passed backward through the dilated pupil with a normal needle-holder, to emerge in their own pockets at 10 and 2 o'clock (Fig. 3d). To prevent damaging the hyaloid, this manreuvre is better performed through an intact zonule, before extraction of the cataract. Now cryoextraction can take place, unhindered by the presence of the optic in the lower half of the anterior segment (Fig. 3e). The wound is sutured and the lens centred by pulling on the prolene threads, which are eventually cut to size and buried (Fig. 3f). The threads are cut by cautery, leaving a slight terminal enlargement, which anchors the haptics in the scleral pockets. The main steps of surgery are shown in Figs 4-6. The final aspect of the implanted eye is shown in Figs 8 and 9.
141
Fig.6 The cataract has been extracted. Two of the threads have already been cut and flattened before finally being buried in the 2 and 10 o'clock pockets
Secondary Implantation
The anterior chamber is filled with air, and the vitreous pushed back by orbital hyperbarism. The same cannulated needle-holder is used, and is passed along the posterior surface of the iris to reach the three scleral pockets pFeviously prepared at 12, 4 and 8 o'clock (Fig. 7). No particular problems have been
Fig.4 The lens is drawn into the posterior chamber in front of the crystalline lens
Fig. 7 In secondary implantation two threads are passed through before insertion. The lens is still outside the eye at 12 o'clock. The 4 o'clock thread has already been passed through. In the 8 o'clock scleral pocket the point ofthe needle can be seen on its passage to the exterior
encountered with the vitreous, either during or after surgery. RESULTS Fig. 5 The anterior chamber is washed out before extraction of the cataract. All the threads have already been passed to the extP.rior behind the iris. The lens, still in f~ont of the crystalline, is hardly visible Eur J Imp/ant Ref Surg. Va/3. June 1991
Since 1985, a total of 114 eyes have been implanted: ninety-three cases as primary implantation during intracapsular cataract extraction and 21 cases secondary implantation with a partial or total
C. Maggi, R. Maggi
142
allows open-sky surgery in any eye condition, and over 10 years of anterior chamber implantation sclerally suspended implants have proved to be well tolerated [17]. The postoperative visual acuity was 0.5 or better in 90% of the cases in Groups 3, 4 and 5. The visual results of patients in Groups 1 and 2 were not taken into account as they were dependent on the success of pleoptic treatment, and not on the outcome of the (eventless) surgery. In Groups 3 and 4 there was a lower visual acuity in 10 eyes which was due to cystoid macular oedema (3), retinal detachment (1), involutional or diabetic macular pathology (3) and pre-existent corneal opacity (3). Successfully treated unusual pathology includes: a) primary implantation in two cases of recurrent uveitis (with a follow-up of2 and 4 years respectively, without further relapse); b) two cases of bullous keratopathy with remittance of the corneal symptoms after the anterior chamber lens was replaced with a posterior chamber lens; c) one traumatic cataract had an astigmatic IOL implanted; d) one case of cataract with aniridia was implanted with an 8 mm IOL with an artificial iris and a 3.5 mm pupil.
Fig. 8 Artist's drawing of an implanted eye
Complications
Fig.9 Real view of an implanted eye
absence of the posterior capsule. These cases are divided into five age groups (Table 1). It may seem surprising that 20% of the cases reported are under 12 years of age. Hyperbarism Table 1 p.e. IOL as primary or secondary implant in the absence of capsular support. All primary implantations were performed during IeeE. All secondary implantations were performed after a previous capsulotomy or IeeE (in four cases)
Primary implants Secondary implants Total number of implants
0-1
Age at operation (years) 1-3 3-12 12-40 40-82
2
2
7
11
71
93
5
5
3
6
2
21
7
7
10
17
73
114
Total number of cases
During surgery the air compression ofthe opened eye proved decisive in preventing complications. With intraocular hyperbarism, the anterior chamber is kept constantly full of air, which is easily retained because the intraocular pressure is in balance with the external atmospheric pressure. The air compression greatly accelerates the loss of aqueous from the vitreous, reducing the volume of the eye and increasing the iQtraocular space necessary for implantation. None of the complications which could have been expected from the lack of a posterior barrier were ever encountered. During surgery the position of the vitreous was always controlled by hyperbarism, and vitrectomy was never required. Contact of the vitreous with the PMMA did not cause any problem of transparency. The presence of air probably helped to prevent intraocular bleeding, as it has never occurred, either during or after implantation. Occasional circumscribed haemorrhages did occur when a stab incision of the sclera was used, but they were soon absorbed, and never clouded visibility. In later cases, with the eye wall pierced from the interior using a sharp 0.3 mm corneal needle, trauma to the uvea was greatly reduced. In the postoperative course a shallow anterior chamber or hyphema never Eur J Implant Ref Surg. Vol 3. June 1991
A Posterior Chamber IOL In the Absence of a Capsular Barrier
occurred. Hypertension was present during the first 2 weeks postoperatively in one third ofthe adults with cataract, and always subsided in a few days of routine topical, and only occasionally oral, hypotensive treatment. In no case did the hypertension persist after the second postoperative week, nor was the hypotensive treatment continued. Hypotony, and some clouding of the vitreous, occurred in three adult patients for a maximum 2 month period, and in no case caused impoverished visual acuity. Postoperative astigmatism was always related to the sutures used, then disappeared in the expected time, and in no case could be attributed to the implant. Polypropylene threads were confidently used for the haptics, on the premise that biodegradability of plastics is conditioned by contact with the vascular network of the eye. We recently reported L18] on a Strampelli suspended implant which was explanted after 30 years, and was only damaged in the area where the nylon loops came in contact with the vascularised episclera. In the implant presented here, prolene or dacron monofilament is used in the safe diameter of 0.10 mm in adults, and 0.15 mm in children. The linear course of these haptics in the poorly vascularised sclera, without any points of stress, and with a lack of con-
143
posterior chamber implants were maintained, and the peroperative complications ofICCE prevented, as explained by the following points: 1. One single limbal opening has been maintained, yet allowing three equally spaced points of fixation (at 1200 intervals). The triple haptics prevent pseudophakodonesis and tilting of the implant (Figs 8 and 9). No signs of atrophy of the posterior layer of the iris have been noted up to now. 2. An artificial barrier to the posterior segment is provided by the lens itself. With an intact hyaloid, vitreous prolapse into the anterior chamber through the unprotected periphery is hardly possible (Fig. 10). 3. The slight vaulting of the implant so it is placed behind the iris in a position which almost touches, is spontaneously achieved in the straight passage of the prolene haptic threads from the sclera to the optic. As a consequence, postoperative iridodonesis (one of the drawbacks of the intracapsular method), is practically absent, with pupil motility unhindered by the smooth convex anterior surface of the optic. 4. Problems of vitreous adhesion or transparency have never been encountered because of the firm position of the optic and haptics in the saccadic movements of the eye. Although the maximum follow-up of this posterior chamber implant is only 4 years, its stability was assessed in over 10 years use of the same model as an anterior chamber implant. REFERENCES
2 3 4 Fig. 10 Drawing of the implanted lens seen from behind
5
tact with the uvea, was considered a sufficient guarantee for a long life of the implant.
6
CONCLUSION
8
Posterior chamber lenses are to be preferred to any other implant because of the decreased risk of late damage to the inner tissues of the eye, the prevention of pupillary block, and a reduced ophthalmodonesis. Using the technique described above, an IOL could be implanted in the posterior chamber in the absence of the posterior capsule, or during a planned ICCE. All the above-mentioned advantages of customary Eur J Implant Ref Surg, Vol 3, June 1991
7
9 10
11
DS Durrie, DL Habrich, DR Dietze. Secondary intraocular lens implantation vs epikeratophakia for the treatment of aphakia. Am. J. Ophthalmol., 1987; 103: 384-39l. MM Parks. Visual results in aphakic children. Am. J. Ophthalmol., 1982; 94: 441-449. LJ Girard. Pars plana lensectomy for subluxated and dislocated lenses. Ophthalmic Surg., 1981; 12: 491-495. GA Peyman, M Raichard, MF Goldberg et al. Management of subluxated and dislocated lenses with the vitroplage. Br. J . Ophthalmol., 1979; 63: 771-778. GC Skuta, RP Parrish II, E Hoddap et al. Zonular dyalisis during extracapsular extraction in pseudoaxfoliation syndrome. Arch. Ophthalmol., 1987; 105: 632-634. C Raitta, K Setola. Implantation in exfoliation syndrome and capsular glaucoma. Acta Ophthalmol., 1986; 64: 130-133. GB Siepsen, OR Kline. Aborted posterior chamber intraocular lens insertions: a 'second Choice'. Am. Intra-Oc. Implant Soc. J ., 1984; 10: 51-52. PV Mills, GA Robinson. Use of the A.C. lens in the management of capsule rupture. Implant and Ref Surg., 1987; 6: 50-54. ES Malbran, EJ Malbran, I Negri. Lens guide suture for transport and fixation in secondary IOL implantation after intracapsular extraction. Int. Ophthalmol., 1986; 9: 151-160. HS Wang. Management of a posterior capsule rupture in planned extracapsular cataract extraction and posterior chamber lens implantation. J_ Cataract Refract. Surg., 1986; 12: 73-76. RE Smith, RF Beatty, WS Clifford. Pseudophakic keratoplasty: posterior chamber lens implantation in the presence of ruptured capsule. Ophthalmic Surg., 1987; 18: 344-348.
c. Maggi, R. Maggi
144 12 BV Hu, DH Slim, KA Gibbs, YJ Hong. Implantation of posterior chamber lens in the absence of capsular and zonular support. Arch. OphthalTTUJl., 1988; 106: 416-420. 13 WJ Stark, G Goodman, D Goodman, J Gottsh. Posterior chamber intraocular lens implantation in the absence of posterior capsule support. Ophthalmic Surg., 1988; 19: 240-243. 14 AV Spigelman, RL Lindstrom, BD Nichols et al. Implantation of a posterior chamber lens without capsular support during penetrating keratoplasty or as a secondary lens implant. Ophthalmic Surg., 1988; 19: 396-402. 15 RC Drews. P.C. lens implantation during keratoplasty without posterior capsule support. Cornea, 1982; 6: 38-40.
16 C Maggi. Iperbarismo settoriale in chirurgic oculistica. Boll. Ocul., 1986; 65: 335-341. 17 C Maggi. Pediatric implantation. In Cataract and Refractive Surgery, edited by A.E. Maumenee, W.J. Stark and I. Esente. Florence, Italy, 1987, pp. 11-13. 18 C Maggi, R Maggi. Reliability of plastic haptics in a suspended implant. In Biomaterials in OphthalTTUJlogy. Satellite Symposium to the VII EIIC Meeting, Bologna, 1-4 Sept, 1989.
Received December 1989
Eur J Implant Ref Surg, Vol 3, June 1991
An IOL with direct attachment to the sclera has been implanted in the absence of the posterior capsule in a total of 114 cases: as primary implant during ICCE in 93 eyes, and as secondary implant in 21 eyes. Vitrectomy was not necessary in any patient. No part of the haptics or non-absorbable sutures were left on the surface of the sclera. The haptics were completely embedded in the scleral thickness without sutures and were anchored by their terminal knob. Keywords: Suspensory fixation; Intracapsular extraction; Hyperbaric compression of vitreous implant fixation, which allows the implant to be suspended from the sclera, instead of being wedged In conventional cataract surgery, posterior chamber across the anterior segment, and secondly a special implantation with a preserved capsular barrier is operating table which allows the hyperbaric comconsidered mandatory. However, in a minority of pression of the surgically opened eye throughout surcases this technique is not practicable, because either gery [16]. The implant has a central optic in PMMA, there is an indication for intracapsular extraction preferably of 6.5 or 7 mm diameter, to which three (recurrent uveitis [1], retinal detachment), for len- armed prolene sutures 5 cm in length are attached at sectomy (congenital cataract [2], or dislocation of the 120° intervals (Fig. 1). One thread has a straight lens [3, 4]), or because there is weakness or absence, needle which is inserted into the fenestrated cannula of the posterior capsule (exfoliation syndrome [5, 6], of a special needle-holder (Fig. 2). During insertion, because the threads are attached previous intracapsular extraction, some eye trauto the optic at intervals of 120°, two of them can be mas, peroperative rupture of the posterior capsule). passed in and out ofthe eye through the 160° corneal In all the above cases, an anterior chamber implant opening using a needle-holder. The third needs a [7, 8], or secondary corneal surgery (epikeratoseparate scleral incision at 6 o'clock on the opposite phakia, keratomileusis) are the only methods of surside of the limbus. This manreuvre has been simpligery considered. However, because of a growing fied in the present technique. reluctance to use an anterior chamber implant, various techniques of the implantation ofa conventional posterior chamber lens in the absence of a capsular SURGICAL TECHNIQUE barrier have recently been proposed [9-15]. In all these methods, one or two of the haptics of the Primary implantation implant are fixed to the sclera or iris with 10/0 sutures. Three scleral pockets are made at 2,6 and 10 o'clock We proposed a technique that uses a posterior (Fig. 3), and the limbal incision performed (Fig. 3a). chamber implant in either secondary implantation in The first needle is inserted in a reverse position into a the absence of the capsular barrier, or in a planned fenestrated cannula which allows the free passage of intracapsular extraction. the prolene thread (Fig. 2). The cannula with its armed prolene thread is then passed through the pupil and brought into contact with the inner side of MATERIALS AND METHOD the iris root at 6 o'clock (Fig. 3b). A gentle inverse To achieve these results two innovations have been indentation with the smooth end of the cannula locanecessary, firstly the use of a different kind of lizes the correct position inside the 6 o'clock scleral pocket at 2.5 mm from the limbus. The needle is now Read at the EIIC Congress, Copenhagen, 1988. INTRODUCTION
0955-3681/91/020139 + 06 $03.00/0 © 1991 Bailliere Tindall
Eur J Implant Ref Surg, Vol 3, June 1991
140
C. Maggi, R. Maggi
Fig.l The lens with three armed 0.1 mm prolene haptic threads and special needle-holder. Two of these have a 7 mm curved corneal needle attached, and the third thread is armed with a 7 mm straight corneal needle
Fig. 2 Enlarged view showing the straight needle half-way into its final place in the cannula before use
,.J
'"
,/
~~/ <0'
9/ . . "'-Qy
- . "' ~g
~.
/'
I
,
'
"
L
Fig. 3 Main steps of surgery in primary implantation
Eur J Implant Ref Surg. Vol 3. June 1991
A Posterior Chamber IOL in the Absence of a Capsular Barrier
ejected through the eye wall, piercing the sclera. The prolene thread is pulled out of the eye, drawing the lens in to be laid in the lowest possible position between the iris and the crystalline lens (Fig. 3c). With the lens already inside the eye, the other two needles are passed backward through the dilated pupil with a normal needle-holder, to emerge in their own pockets at 10 and 2 o'clock (Fig. 3d). To prevent damaging the hyaloid, this manreuvre is better performed through an intact zonule, before extraction of the cataract. Now cryoextraction can take place, unhindered by the presence of the optic in the lower half of the anterior segment (Fig. 3e). The wound is sutured and the lens centred by pulling on the prolene threads, which are eventually cut to size and buried (Fig. 3f). The threads are cut by cautery, leaving a slight terminal enlargement, which anchors the haptics in the scleral pockets. The main steps of surgery are shown in Figs 4-6. The final aspect of the implanted eye is shown in Figs 8 and 9.
141
Fig.6 The cataract has been extracted. Two of the threads have already been cut and flattened before finally being buried in the 2 and 10 o'clock pockets
Secondary Implantation
The anterior chamber is filled with air, and the vitreous pushed back by orbital hyperbarism. The same cannulated needle-holder is used, and is passed along the posterior surface of the iris to reach the three scleral pockets pFeviously prepared at 12, 4 and 8 o'clock (Fig. 7). No particular problems have been
Fig.4 The lens is drawn into the posterior chamber in front of the crystalline lens
Fig. 7 In secondary implantation two threads are passed through before insertion. The lens is still outside the eye at 12 o'clock. The 4 o'clock thread has already been passed through. In the 8 o'clock scleral pocket the point ofthe needle can be seen on its passage to the exterior
encountered with the vitreous, either during or after surgery. RESULTS Fig. 5 The anterior chamber is washed out before extraction of the cataract. All the threads have already been passed to the extP.rior behind the iris. The lens, still in f~ont of the crystalline, is hardly visible Eur J Imp/ant Ref Surg. Va/3. June 1991
Since 1985, a total of 114 eyes have been implanted: ninety-three cases as primary implantation during intracapsular cataract extraction and 21 cases secondary implantation with a partial or total
C. Maggi, R. Maggi
142
allows open-sky surgery in any eye condition, and over 10 years of anterior chamber implantation sclerally suspended implants have proved to be well tolerated [17]. The postoperative visual acuity was 0.5 or better in 90% of the cases in Groups 3, 4 and 5. The visual results of patients in Groups 1 and 2 were not taken into account as they were dependent on the success of pleoptic treatment, and not on the outcome of the (eventless) surgery. In Groups 3 and 4 there was a lower visual acuity in 10 eyes which was due to cystoid macular oedema (3), retinal detachment (1), involutional or diabetic macular pathology (3) and pre-existent corneal opacity (3). Successfully treated unusual pathology includes: a) primary implantation in two cases of recurrent uveitis (with a follow-up of2 and 4 years respectively, without further relapse); b) two cases of bullous keratopathy with remittance of the corneal symptoms after the anterior chamber lens was replaced with a posterior chamber lens; c) one traumatic cataract had an astigmatic IOL implanted; d) one case of cataract with aniridia was implanted with an 8 mm IOL with an artificial iris and a 3.5 mm pupil.
Fig. 8 Artist's drawing of an implanted eye
Complications
Fig.9 Real view of an implanted eye
absence of the posterior capsule. These cases are divided into five age groups (Table 1). It may seem surprising that 20% of the cases reported are under 12 years of age. Hyperbarism Table 1 p.e. IOL as primary or secondary implant in the absence of capsular support. All primary implantations were performed during IeeE. All secondary implantations were performed after a previous capsulotomy or IeeE (in four cases)
Primary implants Secondary implants Total number of implants
0-1
Age at operation (years) 1-3 3-12 12-40 40-82
2
2
7
11
71
93
5
5
3
6
2
21
7
7
10
17
73
114
Total number of cases
During surgery the air compression ofthe opened eye proved decisive in preventing complications. With intraocular hyperbarism, the anterior chamber is kept constantly full of air, which is easily retained because the intraocular pressure is in balance with the external atmospheric pressure. The air compression greatly accelerates the loss of aqueous from the vitreous, reducing the volume of the eye and increasing the iQtraocular space necessary for implantation. None of the complications which could have been expected from the lack of a posterior barrier were ever encountered. During surgery the position of the vitreous was always controlled by hyperbarism, and vitrectomy was never required. Contact of the vitreous with the PMMA did not cause any problem of transparency. The presence of air probably helped to prevent intraocular bleeding, as it has never occurred, either during or after implantation. Occasional circumscribed haemorrhages did occur when a stab incision of the sclera was used, but they were soon absorbed, and never clouded visibility. In later cases, with the eye wall pierced from the interior using a sharp 0.3 mm corneal needle, trauma to the uvea was greatly reduced. In the postoperative course a shallow anterior chamber or hyphema never Eur J Implant Ref Surg. Vol 3. June 1991
A Posterior Chamber IOL In the Absence of a Capsular Barrier
occurred. Hypertension was present during the first 2 weeks postoperatively in one third ofthe adults with cataract, and always subsided in a few days of routine topical, and only occasionally oral, hypotensive treatment. In no case did the hypertension persist after the second postoperative week, nor was the hypotensive treatment continued. Hypotony, and some clouding of the vitreous, occurred in three adult patients for a maximum 2 month period, and in no case caused impoverished visual acuity. Postoperative astigmatism was always related to the sutures used, then disappeared in the expected time, and in no case could be attributed to the implant. Polypropylene threads were confidently used for the haptics, on the premise that biodegradability of plastics is conditioned by contact with the vascular network of the eye. We recently reported L18] on a Strampelli suspended implant which was explanted after 30 years, and was only damaged in the area where the nylon loops came in contact with the vascularised episclera. In the implant presented here, prolene or dacron monofilament is used in the safe diameter of 0.10 mm in adults, and 0.15 mm in children. The linear course of these haptics in the poorly vascularised sclera, without any points of stress, and with a lack of con-
143
posterior chamber implants were maintained, and the peroperative complications ofICCE prevented, as explained by the following points: 1. One single limbal opening has been maintained, yet allowing three equally spaced points of fixation (at 1200 intervals). The triple haptics prevent pseudophakodonesis and tilting of the implant (Figs 8 and 9). No signs of atrophy of the posterior layer of the iris have been noted up to now. 2. An artificial barrier to the posterior segment is provided by the lens itself. With an intact hyaloid, vitreous prolapse into the anterior chamber through the unprotected periphery is hardly possible (Fig. 10). 3. The slight vaulting of the implant so it is placed behind the iris in a position which almost touches, is spontaneously achieved in the straight passage of the prolene haptic threads from the sclera to the optic. As a consequence, postoperative iridodonesis (one of the drawbacks of the intracapsular method), is practically absent, with pupil motility unhindered by the smooth convex anterior surface of the optic. 4. Problems of vitreous adhesion or transparency have never been encountered because of the firm position of the optic and haptics in the saccadic movements of the eye. Although the maximum follow-up of this posterior chamber implant is only 4 years, its stability was assessed in over 10 years use of the same model as an anterior chamber implant. REFERENCES
2 3 4 Fig. 10 Drawing of the implanted lens seen from behind
5
tact with the uvea, was considered a sufficient guarantee for a long life of the implant.
6
CONCLUSION
8
Posterior chamber lenses are to be preferred to any other implant because of the decreased risk of late damage to the inner tissues of the eye, the prevention of pupillary block, and a reduced ophthalmodonesis. Using the technique described above, an IOL could be implanted in the posterior chamber in the absence of the posterior capsule, or during a planned ICCE. All the above-mentioned advantages of customary Eur J Implant Ref Surg, Vol 3, June 1991
7
9 10
11
DS Durrie, DL Habrich, DR Dietze. Secondary intraocular lens implantation vs epikeratophakia for the treatment of aphakia. Am. J. Ophthalmol., 1987; 103: 384-39l. MM Parks. Visual results in aphakic children. Am. J. Ophthalmol., 1982; 94: 441-449. LJ Girard. Pars plana lensectomy for subluxated and dislocated lenses. Ophthalmic Surg., 1981; 12: 491-495. GA Peyman, M Raichard, MF Goldberg et al. Management of subluxated and dislocated lenses with the vitroplage. Br. J . Ophthalmol., 1979; 63: 771-778. GC Skuta, RP Parrish II, E Hoddap et al. Zonular dyalisis during extracapsular extraction in pseudoaxfoliation syndrome. Arch. Ophthalmol., 1987; 105: 632-634. C Raitta, K Setola. Implantation in exfoliation syndrome and capsular glaucoma. Acta Ophthalmol., 1986; 64: 130-133. GB Siepsen, OR Kline. Aborted posterior chamber intraocular lens insertions: a 'second Choice'. Am. Intra-Oc. Implant Soc. J ., 1984; 10: 51-52. PV Mills, GA Robinson. Use of the A.C. lens in the management of capsule rupture. Implant and Ref Surg., 1987; 6: 50-54. ES Malbran, EJ Malbran, I Negri. Lens guide suture for transport and fixation in secondary IOL implantation after intracapsular extraction. Int. Ophthalmol., 1986; 9: 151-160. HS Wang. Management of a posterior capsule rupture in planned extracapsular cataract extraction and posterior chamber lens implantation. J_ Cataract Refract. Surg., 1986; 12: 73-76. RE Smith, RF Beatty, WS Clifford. Pseudophakic keratoplasty: posterior chamber lens implantation in the presence of ruptured capsule. Ophthalmic Surg., 1987; 18: 344-348.
c. Maggi, R. Maggi
144 12 BV Hu, DH Slim, KA Gibbs, YJ Hong. Implantation of posterior chamber lens in the absence of capsular and zonular support. Arch. OphthalTTUJl., 1988; 106: 416-420. 13 WJ Stark, G Goodman, D Goodman, J Gottsh. Posterior chamber intraocular lens implantation in the absence of posterior capsule support. Ophthalmic Surg., 1988; 19: 240-243. 14 AV Spigelman, RL Lindstrom, BD Nichols et al. Implantation of a posterior chamber lens without capsular support during penetrating keratoplasty or as a secondary lens implant. Ophthalmic Surg., 1988; 19: 396-402. 15 RC Drews. P.C. lens implantation during keratoplasty without posterior capsule support. Cornea, 1982; 6: 38-40.
16 C Maggi. Iperbarismo settoriale in chirurgic oculistica. Boll. Ocul., 1986; 65: 335-341. 17 C Maggi. Pediatric implantation. In Cataract and Refractive Surgery, edited by A.E. Maumenee, W.J. Stark and I. Esente. Florence, Italy, 1987, pp. 11-13. 18 C Maggi, R Maggi. Reliability of plastic haptics in a suspended implant. In Biomaterials in OphthalTTUJlogy. Satellite Symposium to the VII EIIC Meeting, Bologna, 1-4 Sept, 1989.
Received December 1989
Eur J Implant Ref Surg, Vol 3, June 1991