Capsulorhexis, Phacoemulsification and New Disc Lens Implant

SHORT REPORTS Capsulorhexis, Phacoemulsification and New Disc Lens Implant MAnEO PIOVELLN, ALBERTO MONTERICCIOb and FABRIZIO FORMENTl c

the anterior chamber was opened with a 3.2 mm phaco-Iance, the anterior chamber was completely filled with Healon in order to counterbalance the nucleus push, and the anterior capsule was cut with

Bistituti Clinici di Perfezionamento, Milan, Italy, bClinica 'Vii/a dei Gerani', Trapani, Italy and cOspedale Bol/ate, Milan, Italy

We report our clinical experience using a modified technique of capsulorhexis. This technique was performed by knife, scissor and forceps, and was associated with phacoemulsification and implantation of a single-piece PMMA disc lens (Pharmacia, mod. SOIA). Our procedure was performed on 48 patients with a mean follow-up of 6 months. Fifteen anterior capsule radial ruptures and no posterior capsule rupture occurred. In all cases the lens was implanted in-the-bag and no decentration was observed. Our modified technique seems easier than classic capsulorhexis and the lens used is well suited for the implantation technique described. Keywords: Capsulorhexis; tion; PMMA Disc Lens

Fig. 1 Opening of the anterior capsule with a 15° angle knife

Phacoemulsifica-

INTRODUCTION

Since 1985 we have been developing a surgical technique that allows IOL in-the-bag implantation in 100% of cases. This developed in three stages, starting with extracapsular extraction (1985), intercapsular extraction (1986-1987), and capsulorhexis and phacoemulsification (1988-1989).

Fig. 2

MATERIALS AND METHODS

Capsulorhexis, phacoemulsification and implant of a single-piece PMMA intraocular lens were performed on 48 patients (48 eyes). The age of the patients ranged from 42 to 82 years with a mean age of 65 ± 7 years. The mean follow-up period was 6 ± 2 months. All patients underwent capsulorhexis with knife, scissors and forceps, phacoemulsification and implant of a single piece PMMA intraocular disc lens. To perform our modified capsulorhexis technique Please address alI correspondence to: Matteo PioveIla, Via Ardigo '21,20052 Monza, Milan, Italy. 0955-3681/91/020145+11 $03.0010 © 1991 Bailliere Tindall

Figs 2, 3 Opening of the anterior capsule with microscissors up to the 3 o'clock position (Fig. 2) and the 9 o'clock position (Fig. 3) EurJ Implant Ref Surg, Vol 3, June 1991

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a knife angled at 15° (Fig. 1). The cut starts at the 11 o'clock position and runs parallel to the iris for about 4 mm. The anterior capsule is then opened with microscissors to the 3 o'clock position on the left and the 9 o'clock position on the right. Using special forceps the final round capsulorhexis was completed and the strip of the anterior capsule taken out of the eye (Figs 2-6). Phacoemulsification was performed with the OMS phacomachine, a 30° needle and linear ultrasound power (100% free preselected power). This procedure was performed in the capsular bag (Fig. 7), usually with only one hand, but if necessary with both. A single-piece PMMA intraocular disc lens (mod. 801A Pharmacia) was used. It is a 6 mm optic disc with a complete circular loop haptic of 9 mm. The optic is biconvex and presents two holes at the junction of the ring haptic and optic disc.

Figs 4-6 Results obtained with a special forceps capsulorhexis

RESULTS

In 48 procedures, 15 anterior capsule radial ruptures occurred: in three cases during the capsulorhexis, in 10 cases during the phacoemulsification and in two cases during IOL implantation. No pos-

Fig. 7

Fig. 4

Phacoemulsification

terior capsule rupture occurred. In all the patients the lens was implanted in-the-bag and no decentration was observed. Detachment of Descemet's membrane was only seen once, apparently caused by the sleeve of the phacoemulsification tip. Postoperatively, the eyes remained calm. Fibrin exudation was not seen. No transient intraocular pressure elevation occurred because the viscoelastic substance was always aspirated. Because of the patients selection five of the 48 patients had a pre-existing visual impairment unrelated to the cataract. Excluding those five, all eyes had a visual acuity of at least 7/ 10 or more. We did not observe corneal oedema, and found that postoperative astigmatism was reduced by 50% and a stable refraction was obtained after 1 month. DISCUSSION

Fig. 5

Our modified technique seems to be easier than the classic capsulorhexis and it can be performed more frequently. The tear is easier to control and the Eur J Implant Ref Surg. Vol 3. June 1991

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probability of radial ruptures of the anterior capsule are therefore reduced. Healon is very important in our procedure because it counterbalances the nucleus push on opening the anterior capsule, and thus avoids possible formation of clefts to the equator which the surgeon cannot control in direction or in length. Occasionally after phacoemulsification the point where the knife cut meets that of the scissors may open radially, but with experience, if the first knife cut is curved, no angles exist between the knife and

Figs 9-11

Fig. 8

Insertion of 80lA IOL in the capsular bag

Healon in the capsular bag

Fig. 12 Insertion of 80lA IOL in the capsular bag

Fig. 9

Fig. to Eur J Implant Ref Surg, Vol 3, June 1991

Figs 13, 14 Compressible disc lens configuration

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scissor cuts and the capsulorhexis does not open in a radial direction. During phacoemulsification there were 10 cases in which anterior capsule radial rupture decreased, however these complications occurred in the earlier cases which are included. With increasing experience and skill of application they have now been substantially reduced. The single-piece PMMA intraocular disc lens (mod. 801A Pharmacia) is well suited for the implantation technique described. Its most important characteristics are the high flexibility of the loops which enable insertion through a small opening (6.2 mm) and through the capsulorhexis (5 mm). The adhesion that follows between the anterior capsule remnant and the posterior capsule, in the space between the optic disc and the haptic, limits decentration of the IOL. The complications we experienced occurred mainly with the first lenses implanted, which are all included in the evaluation. As our technique improved with experience, implantation difficulties substantially decreased. Our experience in the 48 cases has led us to suggest the following points to enable correct implantation. A. Open the anterior chamber to 6.2 mm. B. Capsulorhexis must be no smaller than 5 mm in diameter; this prevents a radial opening of the anterior capsule occurring during implantation. C. During implantation never release the lens before the loops open inside the small aperture of the capsular bag. The appropriate movement is to push the IOL in and down. D. If the loops open onto the anterior capsule, out of-the-bag, withdraw the IOL from the eye and start again. The insertion must be performed slowly but without stopping (Figs 8-14). E. We do not recommend this type of lens in highly myopic eyes as they are too small for the larger bag: we suggest that this technique lends itself to insertion of lenses above 15 dioptres in power.

REFERENCES D.J. Apple et al. A comparison of ciliary sulcus and bag fixation of posterior chamber intraocular lenses. Am. Intraocular Implant Soc., 1985; II: 44-73. D.J. Apple et al. Postimplantation loop configuration. J. Cataract Refract. Surg., 1986; 12: 363-366. D.J. Apple et al. Correlation of positioning holes and optic edges with the pupillary aperture and visual axis. J. Cataract Refract. Surg., 1986; 12: 367-371. A. Galand. Implantation dans Ie sac capsulaire. J. Fr. Opthal· mol., 1983; 6: 533-535. K. Miyake & C. Miyake. Intraoperative posterior chamber lens haptic fixation in the human cadaver eye. Ophthalmic Surg., 1985; 16: 230-236. T. Neuhann. Theories und Operationstechnik der Kapsulorhexis. Klin Monatsbl Augenheilkd. 1987; 190: 542-545.

M. Piovella & A. Montericcio. Estrazione intercapsuiare di cataratta ed impianto di IOL nel sacco capsulare. Viscochirurgia, 1987; 3: 11-16. E.S. Rosen & I. Kalb. Intercapsular Cataract Extraction. Pergamon Press, Oxford, 1988. J.P. Smith. Pigmentary open angle glaucoma secondary to posterior chamber lens implantation and erosion of the iris pigment epithelium. Am. Intraocular Implant Soc. J .• 1985; II: 171-174.

APPENDIX Question 1

Surely the advantage of a phacoemulsification technique is the small incision. Why open the section even to 6.2 mm to insert a lens? Does this imply that you have no confidence in the lenses capable of insertion through a small incision?

Answer

We prefer to choose a well tested and safe material as PMMA and to avoid implantation of IOL models not perfectly designed for in-the-bag implantation. We do occasionally use a PMMA lens with an optic disc of5mm.

Question 2

Experience with the Pharmacia Compressible Disc BOlA lens confirms that its diameter of9 mm is probably too small, allowing some movement within the capsular bag, with resulting minor decentration of the lens optic. You acknowledge that in larger ,eyes, i.e. myopic eyes this is a real prospect, but can you confirm that the lenses remain central in all your 4B cases. If so how was centration assessed?

Answer

Our results today with the lens 801A is that even in the presence of an anterior capsule radial tear, the 'closed-loop' lens, i.e. without spring effect of the usual design does not cause decentration. Our experience with highly myopic eyes shows a stronger retraction of the capsular bag and this gave us increased concern that decentration may occur with prolene looped lens implants when we compared our results with emmetropic eyes. For this reason we decided to limit the use of the 801A disc lens to dioptres 15-30. As a result we have never seen decentration. Eur J Implant Ref Surg. Vol 3. June 1991

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Question 3

The continuous capsulotomy or capsulorhexis provides the advantage of a secure capsular bag for implantation. Your technique indicated quite a high incidence of radial ruptures for a variety of reasons. Is this simply a question of experience. The more experience you have the less ruptures are likely to occur? Answer

In the beginning it was difficult to perform phacoemulsification all in-the-bag through a small capsulorhexis, but by the time our surgical technique was fully developed the incidence of radial ruptures did reduce. For example in the last 15 implantations there was only one anterior capsule radial rupture. Editor

This paper indicated the feasibility of the above described technique and the satisfaction obtained with a compressible disc lens.

Viscoelastic Material in Dislocated Lens Extraction S. LAKE, N. DIMITRAKOULlAS, N. GEORGIADIS and V. MOSCHOU Aristotelian University of Thessaloniki, Eye Clinic, AHEPA Hospital, Thessaloniki, Greece

Lens dislocation is the most common ocular sign of homocystinuria. The management of one case with pupillary block glaucoma due to the anterior dislocation of the lens is described. Viscoelastic material (Healon) was used to prevent posterior dislocation of the lens during the operation. Keywords: Homocystinuria; Viscoelastic material; Lens extraction INTRODUCTION

Lenticular ectopia is an inheritable condition and can occur as an isolated abnormality, or as a part of Please address all correspondence to: Dr Simeon Lake, 5 Papa· kiritsi Str., 551 33, Kalamaria, Greece. Eur J Implant Ref Surg, Vol 3, June 1991

heritable systemic conditions with a variety of inheritance modes. These are homocystinuria, Marfan's syndrome, Weill-Marchesani syndrome and sulphite oxidase deficiency [1]. Homocystinuria, an autosomal recessive condition, is associated with a deficiency of cystathionine synthase, an enzyme that catalyses the condensation of homocysteine conversion of methionine to cysteine. Systemic manifestations include malar flush, mental retardation, osteoporosis, pectus excavatum, decreased joint mobility and eczema. Thrombo-embolic phenomena, especially after venous or arterial puncture or general anaesthesia can occur. For this reason general anaesthesia is to be avoided if possible. There have been several deaths after lens surgery [1, 2]. Subluxation of the lens is the most important ocular complication. The ectopia lentis, usually downward, tends to be progressive, while in Marfan's syndrome the displacement of the lens is usually upward. Other eye manifestations are high myopia, retinal detachment and possible occurrence of glaucoma as a consequence of lenticular dislocations. Less frequent but well documented ocular complications include cataract, spherophakia, peripheral retinal degeneration, optic atrophy and central retinal artery occlusion. Abnormal physical findings are usually apparent by the age of9; however, they can be absent until 30 [1-41.

The dislocated lens may stay asymptomatic for a long time but for various reasons surgical intervention is necessary. There are different methods for the removal of these lenses. The main problem is the risk of the posterior dislocation into the vitreous cavity. The methods proposed for dislocated lens removal are: (1) intracapsular lens cryoextraction; (2) discission-aspiration of the lens; and (3) lensectomy with vitrectomy instrument combined with anterior vitrectomy r5, 6]. Among the methods proposed for preventing posterior dislocation of the lens are the use of two crossed needles or a pars plana infusion cannula which displaces the lens anteriorly [7]. OUR CASE

A seven-year-old girl was examined 3 years ago. At the first examination the diagnosis was homocystinuria. The systemic symptoms were mild mental retardation and the ophthalmological findings were high myopia, spherophakia, iridodonesis and lens dislocation. The lenses were bilateral, symmetric and downward dislocated. The degree of dislocation was mild, Grade II, according to the Casper and