Special Indications for Hydrogel IOLs. Small-incision Technique with Iridoplasty

Special Indications for Hydrogel IOLs. Small-incision Technique with Iridoplasty D.T. PHAM, J. WOLLENSAK and E. WELZL-HINTERKÖRNER Eye Clinic

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Klinikum Charlottenburg, Free University Berlin, Spandauer Damm 130, 0-1000 Berlin 19

We reviewed 38 patients following cataract surgery with posterior chamber lens (PCL) implantation and iridoplasty: in 18 eyes p-HEMA lenses ('IOGEL' PC 12) were inserted by small incision technique and in 20 eyes PMMA lenses with polypropylene haptics were implanted as controls. All operated eyes achieved the best possible visual acuity. The p-HEMA lenses were weIl tolerated in the postoperative period up to 12 months. Moderate fibrin exudate was observed in two eyes but no synechiae to the PCL developed. In the PMMA group, precipitates on the lens surface and posterior synechiae were seen in six eyes. Thus the p-HEMA lens appears to be a better alternative to the PMMA lens for eyes with a tendency to severe postoperative inflammatory reactions, including eyes that have been previously operated on, and glaucomatous eyes with constricted pupils. Keywords: Hydrogel-IOL; Small incision; lridoplasty

INTRODUCTION

The main advantage of soft intraocular lenses (IOL) is that they can be folded for insertion through a small incision following phacoemulsification. Over the past few years, more surgeons have been using Hydrogel IOLs because ofthe beneficial hydrophilic nature of the polyhema material [1, 2, 4]. Clinical results have demonstrated excellent biocompatibility of Hydrogel IOLs in human eyes, although longterm follow-up results are not available [2-5]. In the early postoperative stage, a severe anterior chamber reaction may occur when immoderate manipulation ofthe iris is necessary. In aseries of6000 implantations of PMMA lenses, we found that fibrin exudates and posterior synechiae occurred significantly more frequently after cataract surgery with iridoplasty [6]. During the last two years we have therefore implanted p-HEMA lenses ('IOGEL') in eyes which required iridoplasty due to constricted pupils. The aim of the current study is to compare the reactions of these eyes with eyes in which PMMA lenses have been implanted. MATERIALS AND METHODS

Criteria for inclusion in the study were senile cataract and constricted pupil smaller than 3 mm after 0955-3681/921010025+03 $03.00/0 © 1992 Bailliere Tindall

chronic use of miotics. Thirty-eight patients were divided into two groups: in 18 eyes p-HEMA lenses ('IOGEL' PC-12) were implanted. Twenty control eyes received a PMMA lens with polypropylene haptics (Type Simcoe). Indomethacine eye drops were given preoperatively. Postoperatively, all eyes were treated with topical dexamethasone. Follow-up examinations were carried out on the first day, after 1 week and minimally 3 months after surgery. They consisted of an evaluation of the changes in the cornea, of anterior chamber flare, as weIl as presence of the fibrin exudate, cell deposits, precipitate and posterior synechiae. The findings were graded in three categories: low (+), moderate (++) and high (+++). Operative technique

All operations were performed by the same surgeon with the same technique. The limbal incision was 7mm with PMMA and 3.5mm with p-HEMA implanted eyes. A sector iridotomy was created before the opening of the anterior capsule, by capsulorhexis. Phacoemulsification and aspiration of the lens cortex were then performed followed by vacuum cleaning of the posterior capsule as weIl as removal of epithelium from the anterior capsule flap. The scleral incision Eur J Implant Re' Surg, Vo14, March 1992

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D.T. Pham et al.

was then enlarged to 3.5 mm. The capsular bag was filled with a viscoelastic substance ('Healon') and the p-HEMA lens was folded with a special forceps (Alcon) and inserted into the inferior capsular bag. The superior flange must be tilted forward to ensure placement of the entire lens in the capsular bag. Finally, the iridotomy was repaired and aspiration of the viscoelastic substance was performed. The limbal incision was closed with a double running suture. RESULTS Biocompatibility

On the first postoperative day, anterior chamber reactions were generally quieter in the p-HEMA group (16 eyes with p-HEMA as compared to 10 with PMMA lenses had a low level of cellular reactions). Within the first postoperative week transient fibrin exudate with moderate cellular reactions was observed in three eyes with PMMA lenses and in two eyes with p-HEMA lenses. Posterior synechiae to the IOL and precipitates on the IOL surface were found in six eyes with PMMA implants. Three of these eyes showed increased capsular opacification (Fig. 1). In the p-HEMA group only one eye had

Table 1 Changes in corneal astigmatisms (D) lncision Preoperatively One week Three months postoperatively postoperatively 3.5mm (p-HEMA) 0.9 ± 0.8 1.0 ± 0.9 1.7 ± 0.9 7.0mm (PMMA) 0.8 ± 0.5 1.0 ± 0.7 2.7 ± 1.6

operative period. In the first postoperative week, the average corneal astigmatism ofthe Hydrogel group, as well as the variation of astigmatism within the group, was less than in the PMMA group. In the Hydrogel group a change in astigmatism from with-the-rule to against-the-rule was found in one eye (1.0/0° preoperatively and 2.5/90° postoperatively). In all other eyes the change ofthe axis was less than 30°. After 3 months, four eyes in the PMMA group had an against-the-rule astigmatism, although the mean astigmatism of the two groups was subsequently similar (Table 1).

Fig. 2 p-HEMA ('IOGEL') implant in situ

Visual acuity

Fig. 1 Posterior synechia and capsular fibrosis in an eye with PMMA implant

posterior synechiae of the iris to the residual anterior capsular flap. There were no synechiae to the p-HEMA lens and this result was statistically significant.

The predicted acuity by retinometry was reached in most cases. Compared with the preoperative visual acuity (Figs 3, 4), a mean improvement of four lines was achieved in both groups.

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Table 1 shows the changes in mean corneal astigmatism measured by keratometry over the post-

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Fig.3 Change ofvisual acuity in p-HEMA-implanted eyes Eur J Imp/ant Ref Surg, Vo/4, March 1992

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The major problem of soft lenses implanted through a small incision is the difficult implantation technique. In addition, folded Hydrogel lenses are particularly vulnerable because of their low mechanical stability [1, 7]. In the hands of experienced surgeons, however, p-HEMA lens can be safely implanted. In eyes with a tendency to severe postoperative reactions due to miosis from glaucoma therapy, postiritis or previous surgery, p-HEMA lenses offer distinct advantages over PMMA lenses.

Fig.4 Change ofvisual acuity in PMMA-implanted eyes

DISCUSSION

REFERENCES 1 L Allarakhia, RL KnolI, RL Lindstrom. Soft intraocular lenses. J. Cataract Refract. Surg., 1987; 13: 607-620. 2 GD Barrett, H Beasley, OJ Lorenzetti, A Rosentha!. Multicenter trial of an intraocular hydrogellens implant. J . Cataract Refract. Surg., 1987; 13: 621-626. 3 KR Mehta, SN Sathe, SD Karyekar. The new soft intraocular lens implant. J. Cataract Refract. Surg., 1978; 4: 200-204. 4 R Menapace, Ch Skorpik, M J uchem, W Scheidei, R Schranz. Kleinschnitt-Technik in der Kataraktchirurgie: Implantation flexibler P- HEMA- Hinterkammerlinsen über die Phakoemulsifikationsöffnung. Bericht über 100 Fälle. Spektrum Augenheilkd, 1988; 2/6: 278-283. 5 V Huber-Spitzy, I Baumgarner, GGrabner. Hydrogel-Hinterkammerlinsen. Erste klinische Erfahrung. In 2. Kongress der Deutschen Gesellschaft für Intraokularlinsen Implantation. Enke Verlag, 1989; 184-187. 6 U Kraffe!. Ergebnisse von 6000 Implantationen von Hinterkammerlinsen (Typ Simcoe) nach Kataraktextraktion. Dissertation FU Berlin 1988. 7 DT Pham, J Wollensak, C Wiemer. Ergebnisse der kapselsackfixierten weichen IOL (Poly-HEMA). 3Kongreß der Deutschen Gesellschaft für Intraokularlinsen Implantation. Springer, Wien, New York; pp 105-110. 8 DT Pham, J Wollensak, C Wiemer. Implantation der heparin modifizierten Hinterkammerlinsen in der Kataraktchirurgie mit Iridoplastik. 4.Kongreß der Deutschen Gesellschaft für Intraokularlinsen Implantation; Springer, Berlin, Heidelberg, New York; pp 301-305.

During the late postoperative period posterior synechiae were significantly more frequent in eyes with PMMA lenses. We have seen synechiae ofthe iris to the lens in at least 1 quadrant in six of 20 eyes. Three of these eyes precipitated massive deposits on the lens surface and capsular opacification increased. However, posterior synechiae of the iris to the residual anterior capsular flap developed in only one eye with a p-HEMA lens. This absence of synechiae to the lens is a benefit of the p-HEMA over the PMMA or heparin-surface-modified PMMA posterior chamber lenses [8]. In addition, small inclslon surgery allows improved stability of the globe. Corneal astigmatism changes were minimized to within 1D throughout the 3-month follow-up period. All eyes with implanted Hydrogel lenses achieved their best predicted visual acuity except one eye which developed an arterial branch occlusion 2 months after surgery. Received May 1990

Eur J /mp/ant Re' Surg, Vo/4, March 1992