1. Iris capture within the groove of the IOL was observed in three eyes and could be repositioned surgically. To avoid this complication, the surgical procedure was adapted by using Miochol® at the end of the surgery, by suturing the corneal incision water tight and by using pilocarpine in the early postoperative period.
2. In one eye of a child where the rhexis was oversized (> 6 mm), the IOL luxated postoperatively into the vitreous. Performing a vitrectomy, the IOL could be removed through the pupil and the corneal incision, and was replaced by a sul-cus-fi xated IOL. Since the ring caliper of 5 mm (Morcher®, Germany, 67-PS1) was used routinely, an oversized or undersized capsulorhexis did not occur anymore.
In the 60 successfully implanted eyes the mean follow-up period was 22.7 months, ranging from 12 months to 68 months (Fig. 3).
The mean postoperative best corrected visual acuity, of the 29 adult eyes suffering from senile cataract only, was 1.02 (SD 0.20). In 24 patients the mean difference between the target refraction calculated with 119.0 as A-constant and the achieved refraction was –0.51 diopters (SD 0.82 D) (Fig. 4).
A
B
Fig. 5.
A. The twin rhexis implant in the two largely dilated eyes of a 54 year old man. 2 years postoperatively no LECs or fi brosis can be found within the visual axis. Surprisingly also LEC growth at the periphery of capsular bag is very limited.
B: Twin rhexis lens 3 years after implantation in one eye of a 59 year old man, showing no fi brosis and no Elsching pearl formation in the central optical zone. In the periphery of the capsular bag slight fi brosis is visible, but Elschnig pearls are absent.
X.5. RESULTS
The twin rhexis lens could be implanted in 61 out of the 63 eyes selected for im-plantation. In these eyes, no peroperative complications such as vitreous prolapse were encountered. In the fi rst eye of one surgeon (VDG) and the third eye of the other surgeon (MJT), the capsules did not slip properly into the groove due to an undersized rhexis (< 4.5 mm). In these cases, the lens was removed through the same incision and replaced by a classical foldable lens-in-the-bag.
Postoperative infl ammation was clinically comparable to the lens-in-the-bag implan-tation technique. Two types of early complications were observed:
Fig. 3. Diagram demonstrating the follow-up time of all 60 eyes.
��
Fig. 4. Diagram showing the difference (in diopters) between the calculated and the achieved spherical equivalent refraction of 24 patients.
Chapter X BAG-IN-THE-LENS 1 YEAR FOLLOW-UP
No important infl ammatory reaction was observed in the postoperative period. None of the patients needed fl uoangiography to exclude postoperative macula edema.
The visual axis remained extremely clear in all eyes, even in the children (Figs. 5, 6, 7). Very moderate intercapsular LEC growth was present at the periphery of the capsular bag. No wrinkling or fi brosis of the remaining capsular bag was observed.
X.6. DISCUSSION
This clinical study confi rms the results of our in vivo and in vitro studies (Tassignon et al., 2002; De Groot et al., 2003; De Groot et al., 2005) that the bag-in-the-lens IOL is a valuable option to eradicate PCO provided the surgery is performed in a proper way.
The tight fi tting of both capsules around the peripheral groove surrounding the optic blocks LEC migration and LEC proliferation to the remaining peripheral capsular bag.
The visual axis was perfectly transparent in all eyes including those of the children.
It is however known that infants and children are at risk for PCO (Koch and Kohnen, 1997; Mullner-Eidenbock et al., 2003; Vasavada et al., 2004) even after a PCCC (Ram et al., 2003). Since LECs are able to grow on the anterior hyaloid surface after hav-ing performed a PCCC (De Groot et al., 2003), Vasavada et al. (2001) correctly ad-vised to add an anterior vitrectomy even when using optic capture in children. Using the bag-in-the-lens in children, no anterior vitrectomy is needed, which is a major advantage considering the physiology of the ocular barriers.
Postoperative infl ammation was clinically negligible as expected after uneventful cataract surgery. Fluoangiography was not necessary in any case since no clinical macular edema was suspected postoperatively. PCCC has been performed since 1990 (Gimbel et al., 1990; Galand et al., 1996). These authors agreed on the inocuity of
Fig. 7. A bag-in-the-lens IOL implanted in a 4-year-old girl (A) and a 5-year-old boy (B) now respectively 5 and 3 years after implantation. This visual axis remains perfectly clear. Mild LEC growth is visible but is limited to the remaining peripheral lens capsule.
A B
Based on the data of 58 healthy eyes operated since and having a postoperative visual acuity of 0.8 and a follow-up of at least 6 months, the A-constant was recal-culated and found to be 118.4.
Fig. 6. Both eyes of a 62 year-old patient, 3 years after bilateral cataract surgery.
Right side: the twin rhexis implant, showing a per-fect transparency of the visual axis and almost no LEC proliferation at the periphery.
Left side: implanted with a classical IOL of the same material (Morcher 92 S), showing slight fi brotic changes and Elschnig pearls on the posterior capsule within the visual axis and at the periphery.
Chapter X BAG-IN-THE-LENS 1 YEAR FOLLOW-UP
X.7. REFERENCES
Apple DJ, Solomon KD, Tetz MR, Assia EI, Holland EY, Legler UF, Tsai JC, Castaneda VE, Hoggatt JP, Kostick AM. Posterior capsule opacification. Surv Ophthalmol 1992; 37:73-116
Apple DJ, Peng Q, Visessook N, Werner L, Pandey SK, Escobar-Gomez M, Ram J, Auffarth GU. Eradi-cation of posterior capsule opacifiEradi-cation. Documentation of a marked decrease in neodymium:
yttrium-aluminum-garnet laser posterior capsulotomy rates noted in an analysis of 5416 pseu-dophakic human eyes obtained postmortem. Ophthalmol 2001, 108:505-518
Auffart GU, Salvetat ML, Chizzolini M, et al. European PCO Study Group. Comparison of Nd:YAG cap-sulo-tomy rates following phacoemulsification with implantation of PMMA, silicone or acrylic intraocular lenses in four European countries. Ophthalmic Epidemiol 2004; 11:319-329 Aslam TM, Aspinall P, Dhillon B. Posterior capsule morphology determinants of visual funtion.
Graefes Arch Clin Exp Ophthalmol 2003; 241:208-212
Beltrame G, Salvetat ML, Chizzolini M, Driussi GB, Busatto P, Di Giorgio G, Barosco F. Posterior cap-sule opacification and Nd:YAG capsulotomy rates after implantation of silicone, hydrogel and soft acrylic intraocular lenses: a two-year follow-up study. Eur J Ophthalmol 2002; 12:388-394 Dana MR, Chatzistefanou K, Schaumberg DA, Foster CS. Posterior capsule opacification after
cata-ract surgery in patients with uveitis. Ophthalmol 1997; 104:1387-1393
Davison JA. Neodymium:YAG laser posterior capsulotomy after implantation of Acrysof intraocular lenses. J Cataract Refract Surg 2004; 30:1492-1500
De Groot V, Hubert M, Van Best JA, Engelen S, Van Aelst S, Tassignon MJ. No fluorophotometric evi-dence of aqueous-vitreous barrier disruption after posterior capsulorrhexis (PCCC). J Cataract Refract Surg 2003; 29:2330-2338
De Groot V, Vrensen G, Willekens B, Van Tenten Y, Tassignon MJ. In vitro Study on the closure of Posterior Capsulorhexis in the human Eye. Invest Ophthalmol Vis Sci 2003; 44:2076-2083 De Groot V, Tassignon MJ, Vrensen GFJM. “Bag-in-the-lens” implantation effectively prevents
sec-ondary posterior capsule opacification: in vitro study on human eyes and in vivo study in rab-bits. J Cataract Refract Surg 2005; 31-398-405
Galand A, Van Cauwenberge F, Moosavi J. Posterior capsulorhexis in adult eyes with intact and clear capsules. J Cataract Refract Surg 1996; 22:458-461
Gimbel HV, Neuhann T. Developments, advantages and methods of the continuous circular capsu-lorhexis technique. J Cataract Refract Surg 1990; 16:31-37
Koch DD, Kohnen T. A retrospective comparison of techniques to prevent secondary cataract forma-tion following posterior chamber intraocular lens implantaforma-tion in infants and children. Trans Am Ophthalmol Soc 1997: 95:351-365
Meacock WR, Spalton DJ, Boyce J, Marshall J. The effect of posterior capsule opacification on visual function. Invest Ophthalmol Vis Sci 2003; 44:4665-4669
Mullner-Eidenbock A, Amon M, Moser E, Kruger A, Abela C, Schlemmer Y, Zidek T. Morphological and functional results of AcrySof intraocular lens implantation in children: prospective randomized study of age related surgical management. J Cataract Refract Surg 2003; 29:285-293
Nishi O, Nishi K, Wickstrom K. Preventing lens epithelial cell migration using intraocular lenses with sharp rectangular edges. J Cataract Refract Surg 2000; 26:1543-1549
Pandey SK, Apple DJ, Werner L, Maloof AJ, Milverton EJ. Posterior capsule opacification: a review of the aetiopathogenesis, experimental and clinical studies and factors for prevention (review).
Indian J Ophthalmol 2004; 52:99-112
Paul T, Braga-Mele R. Bimanual microincisional phacoemulsification: the future of cataract surgery?
Curr Opin Ophthalmol 2005; 16:2-7
Rakic JM, Galand A, Vrensen GFJM. Separation of fibers from the capsule enhances mitotic activity of human lens epithelium. Exp Eye Res 1997; 64:67-72
this manoeuvre on the ocular barriers’ integrity. This was also confirmed by fluo-rophotometrical measurements comparing eyes operated for cataract with PCCC and without PCCC (De Groot et al., 2003).
After the introduction of the sharp edge IOLs by Nishi et al. (2000), PCO presented a dramatic decrease. However, early PCO needing Nd:YAG laser capsulotomy was still found to be 1 % to 2 % by Davison (2004). These authors found a cumulative Nd:
YAG laser capsulotomy rate of 8 % at three years and 11 % at 4 years, which still corresponds to a considerable expense for the health care budgets worldwide.
Our surgical experience shows that the bag-in-the-lens implantation technique, al-though slightly more difficult than the classical lens-in-the-bag implantation, can be used routinely provided some important steps are taken into consideration:
1. A precise anterior CCC: This is rendered easy by using an appropriate caliper and even more easy by using the foldable ring caliper of 5 mm.
2. A posterior CCC matched with the anterior CCC: After injection viscoelastic under the posterior capsule into the space of Berger, the posterior capsule will touch the anterior CCC, making it easy to obtain a matched PCCC by following the border of the ACCC.
3. Avoid injecting too much viscoelastic into the space of Berger, since overfilling of the posterior segment will narrow the anterior chamber and enhance the risk of iris incarceration in the early postoperative period.
4. Partial removal of the viscoelastic from the Berger space can be done in eyes where the separation of the anterior hyaloid from the posterior capsule needed a relatively large volume of viscoelastic.
5. Taking care that the capsular bag remains collapsed for easy IOL insertion, in other words do not inject viscoelastic between both capsular blades.
6. Maintain anterior chamber stability with viscoelastic while inserting the IOL.
7. Miochol® injection immediately after IOL positioning in order to avoid iris in-carceration in the lens groove.
8. Watertight closure of the corneal incision.
9. Pilocarpine 2 % twice dialy in the early postoperative period.
10. When combined to a vitrectomy, keep the iris dilated for the first postoperative days.
In case of problems with one of these steps, the intervention can be converted at any time in a classical lens-in-the-bag implantation.
We started implanting the bag-in-the-lens in selected cases presenting risks for secundary cataract (children, uveitis). The results however were so convincing that this technique has now become our first choice of lens in all cases. At the time this paper was submitted, 286 lenses have been implanted.
Chapter X
In the last ten years we have witnessed an ongoing improvement in cataract surgery techniques. Still more innovations are in the pipeline. Instead of needing an inci-sion of 6 mm through which the lens can be removed, a 3.0 mm inciinci-sion is currently the rule. Technically it is even possible to remove the lens through a 1 mm incision and an implant that can be fi t through such a small opening is currently under evalu-ation. The refractive results of cataract surgery being almost perfect and the compli-cation rate being very low, make this surgery the most successful over the world.
Only one problem remains: secondary cataract or PCO. LECs remaining in the capsular bag after cataract extraction proliferate and migrate into the visual axis, obliterating the visual axis and causing a decrease of visual acuity over time. Though this com-plication can be treated by Nd:YAG laser capsulotomy, it is not without generating additional costs and possible complications.
PCO does not only cause a decreased vision, but also a decreased elasticity of the capsule, which will become fi brotic and less transparent over time. In addition cap-sule contraction may cause a dislocation of the IOL, which is especially disturbing for multifocal IOLs. The elasticity of the capsule is crucial for the dynamic concept of accommodative IOLs. The increasing stiffness of the capsular bag over time is also the reason for the limited success booked with the currently implanted accom-modative IOLs.
Posterior capsule opacifi cation (PCO) is the most common complication following primary cataract surgery. In the past decade, many experimental and clinical studies have been performed on this topic and have led to a better understanding of the pathogenesis of PCO. A large number of non-surgical strategies to prevent PCO have been tested, but none of them had reached the stage of serious clinical testing.
Recent progress in molecular biology may lead to new therapeutic options in the future, such as immunological or gene modulation approaches. Surgical strategies, IOL-design and biomaterial are for the moment the only serious options available to reduce PCO. Careful surgical aspiration of lens material, in-the-bag implantation of the IOL and the use of IOLs with a sharp optic edge and additionally manufactured
Chapter XI Chapter XI XI Chapter XI Chapter XI XI Chapter XI SUMMARY AND GENERAL DISCUSSION
Ram J, Brar GS, Kaushik S, Gupta A, Gupta A. Role of posterior capsulotomy with vitrectomy and intraocular lens design and material in reducing posterior capsule opacifi cation after pediatric cataract surgery. J Cataract Refract Surg 2003; 29:1579-1584
Tassignon MJ, De Groot V, Smets RME, Tawab B, Vervecken F. Secondary closure of posterior continu-ous circular capsulotomy (capsulorhexis). J Cataract Refract Surg 1996; 22:1200-1205 Tassignon MJ, De Groot V, Vervecken F, Van Tenten Y. Secondary closure of posterior continuous
curvilinear capsulorhexis in normal eyes and eyes at risk for postoperative infl ammation. J Cataract Refract Surg 1998; 24:1333-1338
Tassignon MJ, De Groot V, Vrensen GFJM. Bag-in-the-lens implantation of intraocular lenses. J Cataract Refract Surg 2002; 28:1182-1188
Van Cauwenberge F, Rakic JM, Galand A. Complicated posterior capsulorhexis: etiology, manage-ment and outcome. Br J Ophthalmol 1997; 81:195-198
Vasavada AR, Trivedi RH, Singh R. Necessity of vitrectomy when optic capture is performed in chil-dren older than 5 years. J Cataract Refract Surg 2001; 27:1185-1193
Vasavada AR, Trivedi RH, Nath VC. Visual axis opacifi cation after AcrySof intraocular lens implanta-tion in children. J Cataract Refract Surg 2004; 30:1073-1081. Erratum in: J Cataract Refract Surg 2004; 30:1826
Chapter XI SUMMARY AND GENERAL DISCUSSION