Ординатура / Офтальмология / Английские материалы / Modern Cataract Surgery_Kohnen_2002

Fig. 7. Posterior chamber intraocular lens at the end of vitrectomy and phacoemulsification to extract a nucleus from the vitreous cavity (arrows: capsulorhexis).

panretinophotocoagulation (endolaser) during vitrectomy since the patient was diabetic with preproliferative diabetic retinopathy.

Intraoperatively in 1 case we detected the existence of a retinal tear in the upper temporal quadrant (right eye), proceeding to its treatment with endolaser and fluid gas exchange, without retinal detachment in the early postoperative period and until now.

In 10 of the 12 cases we implanted a posterior chamber intraocular lens on the capsular remains. In 1 case the intraocular lens was not implanted since the patient was highly myopic and there was not sufficient capsular support. In another case these remains did not permit a sufficiently stable base for the intraocular lens implantation. Consequently it was implanted in the anterior chamber (fig. 8).

In the postoperative period in no case did corneal edema appear, topical treatment being necessary to control the intraocular pressure in a continuous way in 3 cases. One patient developed in the early postoperative period (35 days) regmatogenous retinal detachment by retinal tear in the lower nasal quadrant which was treated by scleral buckling, vitrectomy with fluid gas exchange and tear endophotocoagulation, achieving a flat retina and reaching a final BCVA of 0.2.

Comment

As we have already indicated previously, the dislocation of the nucleus or a fragment of it in the vitreous cavity is an infrequent complication (between 0.4 and

Fig. 8. Anterior chamber intraocular lens 30 days after vitrectomy and phacoemulsification to extract a nucleus from the vitreous cavity.

18%) [7], that is usually associated with phacoemulsification more frequently than other forms of cataract extraction [5, 8], with a likely relationship to the surgical experience of the surgeon performing the technique [5]. Various factors favor the appearance of this complication apart from learning the technique [5, 13], such as capsular pseudoexfoliation, hard nucleus and previously vitrectomized eyes [2].

The treatment of the nucleus fragments remains controversial. Small fragments well tolerated without uveitis, glaucoma or loss of visual acuity can be followed, however, the delay in eliminating the lens remains may induce chronic glaucoma [3, 14], chronic inflammation or cystoid macular edema [3]. Nevertheless, vitrectomy obtains better functional results in the long term than the nonoperated eyes, despite a better a priori tolerance [10]. In the same way vitrectomy achieves less incidence of glaucoma and uveitis compared with the previtrectomy evaluation [9, 15].

Using the technique of three-port pars plana vitrectomy, two methods have been suggested to eliminate the nucleus or its fragments from the vitreous cavity. The first consists in lifting the nucleus after vitrectomy by means of injection of perfluorocarbon liquid up to the pupillary plane and to extract it reopening the corneal or sclerocorneal incision [16–18]. After the protection of the corneal endothelium with viscoelastic material, the nucleus is extracted with the handle [2]. This process has been recommended for very hard nuclei or when regmatogenous retinal detachment coexists [16]. However, it has two disadvantages in our opinion: firstly, having to open the capsulorhexis if it exists,

with the consequent loss of support for subsequent implantation of a posterior chamber intraocular lens and, secondly, the reopening of the corneal incision implies additional endothelial trauma and induction of astigmatism (the incision must be large enough to allow the exit of the nucleus) [19].

The second method is the elimination of the nucleus and its fragments by phacoemulsification in the vitreous cavity [4, 6, 7, 10, 11, 20]. The advantages of this technique are: maintenance of the capsulorhexis [4], non-reopening of the corneal incision [4, 19] and good control of intraocular pressure during the whole procedure by separate infusion port [6]. However, the use of ultrasound in the vitreous cavity implies risks. Retinal damage may occur when ultrasound is used at therapeutic intensities [21]. Histological studies have shown that acoustic energy at low intensities induces lesions in the outer and inner segments of photoreceptors cells. These lesions appear as a discrete pigment reaction visible by indirect ophthalmoscopy [21].

With a greater energy level we can produce a retinal tear and with high energy level we can cause rupture of all the layers of the retina, with tear of choroidal vessels and bleeding into the vitreous cavity [21].

In our series, 41.5% of the cases have reached a final BCVA of 5/10 or better. These results are comparable to those published in series similar to ours in which the authors obtain between 32 and 68% of cases with 5/10 or better [2, 3, 7, 13]. However, 50% only reached between 4/10 and 1/10 and in 1 case the final BCVA was 0.05. Similar results were also obtained by others [2].

The incidence of regmatogenous retinal detachment in our series (1 case, 8.3%) is the same as the data published for retinal detachment after this technique from 5 to 17% [4, 6, 7, 11]. The use of topical medication to control the intraocular pressure was necessary in 25% of our cases. Other authors have needed chronic medication for glaucoma between 7 and 25% [4, 6, 7, 11].

There is no agreement in the published data with the time lapse between cataract surgery and vitrectomy. In our opinion, vitrectomy must be carried out as soon as possible provided that the visualization conditions are sufficient to perform the vitreous surgery without problems, maintaining the control of inflammation and intraocular pressure with topical medication until vitrectomy. Similarly, we prefer that the anterior segment surgeon should not implant the intraocular lens, since the absence of the same enables us to perform a better cleaning of the anterior chamber and a better visualization.

Conclusion

In our opinion the treatment of a dislocated nucleus or a fragment of it should be performed by an expert vitreoretinal surgeon. The technique of choice is vitrectomy with phacoemulsification of the nucleus in the vitreous cavity,

followed by posterior chamber intraocular lens implantation. The use of perfluorocarbon liquids during the vitrectomy, although not necessary, protects the retina.

References

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2Leaming DV: Practice styles and preferences of ASCRS members – 1994 Survey. J Cataract Refract Surg 1995;21:378–387.

3Blodi BA, Flynn HW Jr, Blodi CF, Folk JC, Daily MJ: Retained nuclei after cataract surgery. Ophthalmology 1992;99:41–44.

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7Gilliland GD, Hutton WL, Fuller DG: Retained intravitreal lens fragments after cataract surgery. Ophthalmology 1992;99:1263–1269.

8Emery JM, McIntyre DJ: Extracapsular Cataract Surgery. St Louis, Mosby 1983, pp 340–358.

9Hutton WL, Snyder WB, Vaiser A: Management of surgically dislocated intravitreal lens fragments by pars plana vitrectomy. Ophthalmology 1978;85:176–189.

10Lambrou FH, Stewart MW: Management of dislocated lens fragments during phacoemulsification. Ophthalmology 1992;99:1260–1262.

11Fastenberg DM, Schwartz PL, Shakin JL, Golub BM: Management of dislocated nuclear fragments after phacoemulsification. Am J Ophthalmol 1991;112:535–539.

12Movschovich A, Berrocal M, Chang S: The protective properties of liquid perfluorocarbons in phacofragmentation of dislocated lenses. Retina 1994;14:457–462.

13Kim JE, Flynn HW Jr, Smiddy WE, Murray TG, Rubsamen PE, Davis JL, Nicholson DH: Retained lens fragments after phacoemulsification. Ophthalmology 1994;101:1827–1832.

14Epstein DL: Diagnosis and management of lens-induced glaucoma. Ophthalmology 1982;89: 227–230.

15Peyman GA, Raichand M, Goldberg MF, Ritacca D: Management of subluxated and dislocated lenses with the vitrophage. Br J Ophthalmol 1979;63:771–778.

16Lewis H, Blumenkranz M, Chang S: Treatment of dislocated crystalline lens and retinal detachment with perfluorocarbon liquids. Retina 1992;12:299–304.

17Van Effenterre G, Lemer Y, Lacotte JL et al: Luxation postérieure du cristallin ou d’un implant. Traitement chirurgical utilisant un perfluorocarbone liquide. J Fr Ophtalmol 1992;15:337–342.

18Greve MDJ, Peyman GA, Mehta NJ, Millsap CM: Use of perfluoroperhydrophenanthrene in the management of posteriorly dislocated crystalline and intraocular lenses. Ophthalmic Surg 1993;24: 593–597.

19Ruiz-Moreno JM: Repositioning dislocated posterior chamber intraocular lenses. Retina 1998;18: 330–334.

20Wong D, Briggs MC, Hickey-Dwyer MU, McGalliard JN: Removal of lens fragments from the vitreous cavity. Eye 1997;11:37– 42.

21Bopp S, El-Hifnawi ES, Bornfeld N, Laqua H: Retinal lesions after transvitreal use of ultrasound. Fortschr Ophthalmol 1991;88:442–445.

Prof. Dr. José Mª Ruiz-Moreno, Instituto Oftalmológico de Alicante, Universidad Miguel Hernández (Vitreo-Retinal Unit), Avenida de Denia 111, E–03015 Alicante (Spain)

Tel. 34 902 333 344, Fax 34 965 260 530, E-Mail jm.ruiz@umh.es

Fig. 1. Right eye, patient 1. Complete closure of the anterior capsule opening by a fibrous plaque 2 months after phacoemulsification and IOL implantation without capsular tension ring in a highly myopic eye ( 21 sph, 2 cyl 180°).

Spectacle-corrected visual acuity was 20/40 in his right eye with a refraction of –21 sph, –2 cyl 180°, and 20/40 in his left eye with a refraction of –21 sph, –1.5 cyl 10°. Anterior segment examination disclosed unremarkable conditions and applanation tonometry was 20 mm Hg in both eyes. Posterior segment examination showed normal optic discs with moderate diffuse atrophy of the retina not affecting the macula. Axial length was 31.5 mm in his right eye and 30.9 mm in his left eye. The patient was scheduled for bilateral nonsimultaneous clear lens extraction with intraocular lens (IOL) implantation. The right eye was operated first, using a standard phacoemulsification technique under topical anesthesia. Capsulorhexis of 6 mm was made and after removal of the lens and cortical material, efforts were made to clean the residual lens epithelial cells from the remaining anterior capsule as much as possible. A foldable acrylic hydrophilic IOL of 2D (Stabibag, Ioltech, La Rochelle, France) was implanted in the bag. The postoperative course was uneventful, with uncorrected visual acuity of 20/40 and spectacle-corrected visual acuity of 20/30 with a refraction of –1 sph, –1 cyl 180°. However, 2 months after surgery the patient presented with a drop of vision in his operated eye. Uncorrected and spectacle-corrected visual acuity were 20/200, and anterior segment examination disclosed a complete closure of the anterior capsule opening by a fibrous plaque (fig. 1). YAG-laser anterior capsulotomy was performed, and the patient recovered vision to the level of the immediate postoperative period. Six months after the first surgery, the patient underwent clear lens extraction in his left eye using the same surgical technique, but implanting a 12-mm PMMA capsular tension ring (Tensiobag, Ioltech) before the insertion of a foldable acrylic hydrophilic IOL of 3D (Stabibag, Ioltech). Postoperative course was uneventful, with uncorrected visual acuity of 20/40 and spectacle-corrected visual acuity of 20/30 with a refraction of 0.75 sph, 0.75 cyl 110°. Six months after surgery, anterior segment examination under full dilation of both eyes showed clear media, with anterior capsulotomy in his right eye (fig. 2) and a round 6-mm capsulorhexis in his left eye (fig. 3).

Fig. 2. Right eye, patient 1. After YAG laser anterior capsulotomy.

Fig. 3. Left eye, patient 1. Round 6-mm capsulorhexis 6 months after phacoemulsification and IOL implantation with a 12-mm capsular tension ring in a highly myopic eye ( 21 sph, 1.5 cyl 10°).

Case 2

A 63-year-old woman with bilateral subluxated cataracts of unknown etiology came seeking for surgery. Preoperative exam yielded an uncorrected visual acuity of counting fingers in both eyes. Spectacle-corrected visual acuity was 20/80 in her right eye with a refraction of 16 sph, 3 cyl 80°, and 20/400 in her left eye with a refraction of 23 sph,

Fig. 4. Right eye, patient 2. Subluxated nuclear cataract with 150° of dehiscence affecting the inferior zonula.

3.5 cyl 100° due to profound amblyopia. The patient complained of right eye monocular diplopia. Anterior segment examination disclosed a subluxated nuclear cataract in her right eye with 150° of dehiscence affecting the inferior zonula (fig. 4). Her left eye showed a subluxated cataract with a 90° dialysis in the inferior zonula. In both eyes the anterior hyaloid was intact with no vitreous prolapse in the anterior chamber, but iridodonesis and phacodonesis were evident. Applanation tonometry was 22 mm Hg in both eyes. Posterior segment examination disclosed pale optic discs and moderate diffuse atrophy of the retina sparing the macula in the right eye. The left eye showed posterior staphyloma with extreme chorioretinal atrophy affecting the macula. Axial length was 29.7 mm in her right eye and 33.6 mm in her left eye.

Available options included intracapsular lens extraction with anterior chamber angle-supported or iris-fixated IOL implantation, phacoemulsification with a sutured posterior chamber IOL, or IOL implantation following the use of an endocapsular ring, the latter being the chosen option. The patient was scheduled for bilateral simultaneous cataract surgery with IOL implantation. The right eye was operated first, using phacoemulsification technique under peribulbar anesthesia. After filling the anterior chamber with viscoelastic, a 5.5-mm capsulorhexis was made taking advantage of the intact zonules to provide countertraction. After limited hydrodissection with a 27-gauge cannula a 12-mm diameter PMMA scleral-fixated capsular tension ring (Type 1 L, Morcher GmbH, Stuttgart, Germany) was implanted and secured to the sclera at the 6 o’clock position just in the middle of the zonular dehiscence (fig. 5a–f). Scleral fixation of the endocapsular ring made the lens recentered on the pupil, while the capsular bag expanded and provided enough countertraction to continue with surgery. Removal of the lens and cortical material was made using low vacuum, low aspiration and low infusion. Finally, a foldable acrylic hydrophobic IOL of 5 D (Acrysoft MA60, Alcon, Tex., USA) was implanted into the capsular bag. The left eye was operated using the same technique but a 12-mm PMMA capsular tension ring (Tensiobag,

Fig. 5. Different steps during the implantation of the Cionni’s ring (surgeon’s view). a Capsulorhexis is performed. b A double-armed 10/0 prolene suture passed through the fixation hook of the ring is introduced through the incision, enters the pupil and staying anterior to the anterior capsule exits the eye through the ciliary sulcus and the previously created scleral incision, with the aid of a 25-gauge needle. c The Cionni’s ring is introduced in the capsular bag. d The fixation hook is rotated toward the center of the zonular dehiscence, with subsequent recentration of the subluxated nucleus. e After scleral fixation of the ring, the phacoemulsification has been completed, and the recentered capsular bag is filled with viscoelastic. f Final aspect, with IOL in the bag and perfect centration of the implant.

Fig. 6. Right eye, patient 2. Retroillumination image shows a 2-mm superior decentration of the IOL. Note the Cionni’s ring in the inferior periphery of the capsular bag.

Ioltech) was implanted but not fixated to the sclera because it provided enough capsular support. A foldable acrylic hydrophilic IOL of 3D (Corneal) was implanted into the capsular bag, and one haptic was positioned into the area of zonular dehiscence due to the amount of dialysis present. Stability of the IOL was assessed by performing the ‘bounce-back’ test which consisted on deliberate decentration with spontaneous recentration of the lens.

The postoperative course was uneventful, and 6 months after surgery the patient attained an uncorrected visual acuity of 20/40 in her right eye and counting fingers in her left eye due to severe amblyopia. Anterior segment biomicroscopy revealed a 2-mm superior decentration of the IOL in her right eye (fig. 6), while IOL centration in her left eye was very good (fig. 7). No monocular diplopia was present.

Discussion

The capsular tension ring is manufactured from one-piece PMMA and is available in different sizes depending on the purpose of their use and the size of the eye where it is going to be implanted. They are distributed by many of the companies that make intraocular lenses, including Morcher, Ioltech, Corneal and Ophtec. Capsular tension rings are available in diameters ranging from 10 to 12 mm. The most commonly used are the 10 and 11 mm, whereas the 12 mm one is reserved for eyes with axial length higher than 28 mm. Recently, endocapsular rings as small as 9 mm have been designed for pediatric use. When the ring is in the packaged container the diameter is higher than when it is inserted in the