32 Cataract surgical techniques

Background

Cataract surgery forms the major surgical workload of eye departments throughout the world. Technological advances in equipment, as well as intraocular lens design and drugs, have affected the way surgery is being performed, particularly over the past ten years.

Treatment options

Extracapsular extraction with intraocular lens implantation became the panacea in treatment for cataract patients. However, even though spherical equivalent neutrality could be achieved, problems with postoperative astigmatism remained.

Phacoemulsification emerged as an alternative method for cataract removal, through a small incision in a “closed environment”. Although initially viewed with scepticism, almost 90% of cataract surgery is now performed by this technique.

This chapter aims to present evidence available on surgical techniques involved in cataract removal. The randomised controlled trials (RCTs) discussed are concerned with phacoemulsification, including its comparison with extracapsular cataract extraction (ECCE). Studies which looked solely at ECCE surgery have not been included.

Question

What is the difference in effect on surgical outcome between phacoemulsification and extracapsular cataract extraction?

The evidence

There are nine RCTs that have compared the effects of phacoemulsification (phaco) and ECCE (Table 32.1).1–9

There is evidence for significantly greater postoperative inflammation following ECCE than phaco.1–3 Landau and Laurell showed less “in the bag” placement of IOL (intraocular lens implant) haptics following ECCE.4 A better uncorrected visual acuity (UCVA) was shown in patients who underwent phaco compared to ECCE.1,2,5–7 These

studies, however, differ in the length of time in which there is a statistical benefit in UCVA. No statistical difference was noted in endothelial cell loss between the groups, but the coefficient of variation of endothelial cells was higher following ECCE, as was corneal thickness.1,5 Two RCTs have looked at intraocular pressure levels (IOP) after surgery with differing results.8,9 The IOP at six hours post operatively was higher in the ECCE group in Bömer et al.’s

9 ′′

study, and higher in the phaco group in Jurgens et al.’s study.8 Two RCTs showed significantly less posterior capsule opacification following phaco than ECCE.2,7

No statistical difference was shown between the two techniques with respect to progression of diabetic retinopathy or presence of clinical significant macula oedema following surgery,2 or of the cost of the two techniques with respect to the resources used.7

Comment

Overall, the evidence suggests that phacoemulsification has a number of advantages over ECCE; in particular reduced postoperative inflammation, better IOL placement, better UCVA, less posterior capsular opacification and reduced corneal swelling.

Question

What is the effect of different viscoelastics on surgical outcomes?

The evidence

The consequences of using various viscoelastics may be examined by analysing the IOP and endothelial cell function and morphology (Table 32.2). Comparison between studies was difficult since there was incomplete information as to whether patients were given preoperative, intraoperative, or postoperative medication in all cases, which would have had an effect on the postoperative IOP readings.

Three RCTs have compared the use of hydroxypropyl methylcellulose (HPMC) based products with Healon.10–12 Significantly higher IOP was seen in the Healon group at 24 hours in one study.10 However, the other two RCTs showed

Notes

(Continued)

Notes

Participants Outcomes Results

no difference11,12 but the first had very few patients who underwent phacoemulsification and the second used pneumotonograph for IOP measurements, which could explain the different outcomes. There was a significant increase in corneal thickness at one day postoperatively in an HPMC group compared to Healon but no difference thereafter.12

Four RCTs have compared cohesive with dispersive agents.13–16 No significant difference in IOP at 24 hours postoperatively or endothelial cell dysfunction/loss was seen between Amvisc Plus and Viscoat.13 However, IOP was significantly higher at six hours postoperatively in a Viscoat group compared to Healon 5.14 Miller showed significantly more time was needed to remove Viscoat than Healon GV, but no significant difference was noted in endothelial cell dysfunction between the two groups.15 Koch et al. only showed a significant increase in corneal thickness with

Healon compared with Viscoat at day one postoperatively.16 Three RCTs have looked at different Healon-based derivatives.8,17,18 Higher IOP was seen at six hours with Healon GV compared to Healon in Ju``rgens et al.’s study,8 but no significant difference was seen in Kohnen et al.’s.17 However, in Kohnen et al.’s study preoperative diamox was given. No statistical difference was seen in IOP or corneal thickness postoperatively between patients using Healon or

Microvisc.18

Comment

The evidence suggests that HPMC might produce a lower IOP but more corneal swelling after surgery than Healon. Evidence suggested Viscoat caused raised IOP at 24 hours postoperatively and was more difficult to remove than cohesive agents. Higher viscosity healonoids appear to cause a greater IOP rise at 24 hours.

Question

What is the effect of scleral tunnel depth on surgical outcome?

The evidence

Two RCTs have examined the effect of scleral tunnel depth (Table 32.3).19,20 There was a significantly higher incidence of hyphaema in the deeper scleral tunnel group,19 but no difference was noted in surgically induced astigmatism or wound strength between the two depths.20

Question

What is the effect of a corneal/scleral/limbal located phaco incision on surgical outcome?

The evidence

Four RCTs have compared the effects of scleral tunnel incisions with clear corneal incision,21–24 and four with limbal based incisions25–28 (Table 32.4). In comparing the scleral tunnel incision with the clear corneal (superior or temporal), there was no significant difference in visual acuity between groups postoperatively.21,23,24 There was less alteration in blood aqueous barrier at three days postoperatively and lower IOP at six hours postoperatively with clear corneal incisions than with scleral tunnel incisions.21 Analysis of astigmatism has produced conflicting results with two studies showing less astigmatism,22,23 but Olsen et al. showing greater induced astigmatism in the corneal groups.24 Direct comparison of these studies, however, was not possible since Kurimoto et al.22 looked at absolute postoperative astigmatism,

Cillino et al.23 examined polar values and Olsen et al. examined the changes by vector analysis.

No statistically significant difference was noted in the surgically induced astigmatism between limbal incisions and scleral tunnels after one week.25–27 Gimbel et al.’s study comparing a scleral flap to acute bevelled cataract incision showed greater astigmatism in the latter group, but this may be explained by the effect of sutures rather than location of incision (Table 32.5).26 There was no difference in wound strength between limbal and tunnel groups (whether temporal or superior) after one day.27 There was a lower IOP rise in the tunnel groups at six hours than in limbal, but no difference thereafter.28

Comment

Evidence suggests clear corneal incisions caused reduced inflammation and IOP compared to scleral tunnels. No advantage was seen with respect to the UCVA, and the results were equivocal for astigmatism. Between limbal and scleral tunnels there was no difference in surgically induced astigmatism or wound strength. There was a lower IOP initially in the scleral tunnel group.

Question

What is the effect of incision location on surgical outcome?

The evidence

Studies pertaining to the effect of incision location are tabulated in Table 32.6, all of which examine the effect of location of scleral tunnels.27,29–31 Direct inter-study comparison is difficult since the size of the flaps varies between studies, as does the surgical technique. However, the data suggest a significant reduction in surgically induced

Notes

(Continued)

Notes

Participants Outcomes Results

Notes

OD, ophthalmodynamometer; SIA, surgically induced astigmatism

Phaco, phacoemulsification and intraocular lens implant; UCVA, uncorrected visual acuity; BCVA, best corrected visual acuity; SSD, statistical significant difference;

Notes

(Continued)

Notes

Participants Outcomes Results

over FU

vnylon)

Notes

mm4·0

vmm 3·2

1 × 10/0 nylon radial suture all cases

(Continued)

Notes

Participants Outcomes Results

(Continued)

Notes

Participants Outcomes Results

at 1 yr but not stat sig

vlens) siliconefoldable

siliconemm

3·5 ●

No inSSD changesCT/ECC

●

Holweger and RCT

5 PMMAmm

● (smallest8/12

between atgroups

5 mm – 100 eyes ECC

mm5

v(sutureless) mm3·5

8/12FU

Marefat,

astigmatism in the temporal and BENT (BEtween Nine and Twelve o’clock) location compared to superior incisions.27,29,30 However, no difference was noted in visual acuity.29,30 One study examined wound strength and found no significant difference between temporal or superior scleral flaps.27

The evidence suggests reduced surgically induced astigmatism in the temporal and BENT groups compared to superior incisions but no difference in wound strength or visual acuity.

Question

What is the effect of phaco incision size on surgical outcomes?

The evidence

Thirteen RCTs have examined the effect of the different size of scleral flaps6,32–43 while three have concentrated on clear corneal incisions (Table 32.5).44–46 Inter-study comparison of the scleral flap groups are problematic since apart from the variation in sizes of incision studied, the use of sutures and their tightness will have an effect on astigmatic outcome measures. However, evidence from the studies suggested that smaller incisions were associated with statistically less surgically induced astigmatism and an earlier rehabilitation in visual acuity, particularly uncorrected visual acuity.6,32–41

Further outcome measures in patients who had variation in the size of their scleral tunnels included a higher incidence of hyphaemas in larger incision group,40 significantly lower aqueous humour cell count and flare at one week postoperatively,41 less wound-related flattening at three months,41 and fewer central corneal changes on corneal topography in the smaller incision group.42 No statistical difference was noted with respect to specular microscopy or fluorophotometry between different incision sizes.41,43

For corneal incisions the influence of incision size on outcome appears to be similar to scleral tunnels. There was significantly less astigmatism in the smaller incision group after six months.44 There was no statistical difference in endothelial cell morphology or endothelial cell loss,45,46 or corneal topography changes between incision sizes studied.46

Comment

Overall, the evidence suggests that smaller scleral tunnel incisions were associated with less astigmatism, improved earlier UCVA, reduced incidence of hyphaemas, less

postoperative inflammation, less wound-related flattening, and less change in the central cornea on corneal topography compared to large incisions. Smaller corneal incisions were also associated with reduced astigmatism compared to larger ones.

Question

What is the effect of different phacoemulsification techniques on surgical outcome?

The evidence

Four studies have looked at different techniques for nuclear fractis (Table 32.7).16,47–49 Less corneal endothelial cell loss was shown to occur when performing phaco in the posterior chamber as opposed to iris plane.16 A comparison of divide and conquer to three other techniques, showed less endothelial cell loss at one month compared to Chip and Flip but this was not significant at three months.47 “Reversed Tip and Snip” showed significantly less endothelial cell loss compared with divide and conquer at three months.48 “Phaco chop” showed significantly less phaco time, less phaco power and less equivalent phaco time in comparison to divide and conquer.49 However, there was no difference between the two groups with respect to complications or postoperative visual acuity.

Comment

The evidence suggests that endocapsular phaco surgery is safer than iris plane, and that there are advantages of the newer nuclear fractis techniques.

Question

What is the effect of sutures on phaco incision closure?

The evidence

Table 32.8 summarises RCTs on the effect of sutures on phaco incision closure, which have looked at scleral tunnels (Table 32.8).25,28,26,39,50–55 Intraoperative variations, such as linear versus frown incision, amount of cautery and size of incision (4–7 mm), make it difficult to compare the studies directly using the size of postoperative astigmatism as a outcome measure.

In comparing studies that examined the effect of no suture v one suture (in all cases 10/0 nylon, eight studies),25,28,39,50–54 only one study showed any difference between the two groups with respect to the amount of

Notes

Notes

Phaco lessChop timephaco

● time/Phaco

–D&C eyes55

vChop Phaco

RCT

.,al etWong

surgically induced astigmatism, which was significant at one week postoperative but not at three months.50 However, three studies showed earlier stabilisation of astigmatism in the sutureless incision group.41,51,52 Analysis of surgical outcomes for which there was no statistical difference included computerised videokeratography,53 uncorrected visual acuity,25 and intraocular pressure.28

One study looked at the effect of suture adjustment intraoperatively, and suggested less variation in postoperative astigmatism between the adjusted and unadjusted groups up to two years but this was not statistically significant.54

Azar et al. compared sutureless incisions to closure with one and three sutures.55 They suggested that one stitch closure in a 5·5 mm scleral flap incision was the most astigmatic neutral closure.55 Gimbel et al. compared sutureless closure with three different suture closures and suggested that horizontal suture closure of a 6 mm flap was the most astigmatic neutral closure.26

Comment

Overall, the evidence suggests a minimal difference in induced astigmatism between sutureless and one suture groups, but earlier stablisation of astigmatism in the sutureless group.

Question

What is the effect of different suture material or technique on incision closure?

The evidence

Three RCTs have examined the effect of different suture materials on incision closure38,56,57 and one has examined different techniques of suture tying (Table 32.9).46 Two studies have looked at scleral tunnel incisions,38,56 one at clear corneal incisions46 and one is an objective comparison in a mixture of cases of phaco, ECCE, and intracapsular cataract extractions.57 Mersilene, 9/0 and 10/0 nylon induced statistically more with the rule astigmatism than Prolene and Novafil at day one.38,56 However, by two months there was no statistical difference in the astigmatism or UCVA between the groups.38

Following clear corneal incisions, no statistical difference in corneal topography was noted between one radial suture and one X suture after eight months.48

Comment

Mersilene, 9/0 and 10/0 nylon induced more astigmatism than Prolene and Novafil in the short term. No topographical difference was seen between one radial suture or X suture in incision closure.

Question

What alternatives are there to sutures for incision closure?

The evidence

Table 32.10 tabulates RCTs investigating the effect of incision closure by alternative materials.50,58–60 Three studies compare the effect of scleral tunnel closure with a tissue adhesive (fibrin in two studies, cyanoacrylate in one) to closure with one suture. Cyanoacrylate was shown to be safe and equally as effective as suturing with respect to postoperative astigmatism.50 Both the fibrin studies showed that fibrin was safe and induced significantly less postoperative astigmatism than a single suture. However, no difference was noted in final best-corrected visual acuity between the fibrin group and sutured group.58,59 There was no discussion about the costs of these materials.

One study examined conjunctival closure either manually or after saline injection. Subjective evidence suggested better closure with saline injection after one week but no difference after one month.60

Comment

The evidence suggests adhesive closure is equal to or better than single suture closure with respect to postoperative astigmatism.

Summary

These studies have provided evidence for the benefits of sutureless or single suture closure, small astigmatic neutral incisions, and temporal clear corneal incisions. The evidence from specific surgical techniques along with evidence from Table 32.1 indicates the advantages of phacoemulsification over ECCE. Viscoelastic technology has also improved to enhance the effectiveness of endothelial protection during phacoemulsification. However, only one randomised controlled trial examined the cost-effectiveness of the two procedures. In developing countries where phacoemulsification is now being performed in major cities, the initial investment needed to buy equipment may well put phaco out of the reach of the masses of the rural population who are “blinded” with cataracts. However, distinct advantages such as the reduced rate of posterior capsular opacification, fewer surgical complications, and better UCVA, may well make the initial investment financially viable in the long term.

Notes

(Continued)

Notes

Participants Outcomes Results

suturesNo

●

1/52 no SSD after

1 suture –

vsutureless

8 6,wks,

Notes

ICCE, intracapsular extraction, ECCE, extracapsular cataract extraction via nuclear expression and intraocular lens implant; Phaco, phacoemulsification and intraocular lens implant; UCVA, uncorrected visual acuity; BCVA, best corrected visual acuity; SSD, statistical significant difference; SIA, surgically induced astigmatism; Ethilon, monofilament nylon polyamide-6; polyglactin 910 (vicryl), copolymer of lactide and glycolide; Prolene, polypropylene; Mersilene, polyester; Novafil, polyethylene; AR, against the rule astigmatism; WR, with the rule astigmatism; CT, corneal topography

Notes

Phaco, phacoemulsification and intraocular lens implant; UCVA, uncorrected visual acuity; BCVA, best corrected visual acuity; SSD, statistical significant difference;

2 thrombin/CaCland

protein/apoproteincomponents

surgicallySIA, astigmatism;induced fibrinTissucol, 2sealant

References

1.Laurell CG, Zetterström C, Philipson B et al. Randomized study of the blood–aqueous barrier reaction after phacoemulsification and extracapsular cataract extraction. Acta Ophthalmol Scand 1998;76: 573–8.

2.Dowler JG, Hykin PG, Hamilton AM. Phacoemulsification versus extracapsular cataract extraction in patients with diabetes.

Ophthalmology 2000;107:457–62.

3.Chee SP, Ti SE, Sivakumar M et al. Postoperative Inflammation:

extracapsular cataract extraction versus phacoemulsification.

JCataract Refractive Surg 1999;25:1280–5.

4.Landau IE, Laurell C-G. Ultrasound biomicroscopy examination of intraocular lens haptic position after phacoemulsification with continuous curvilinear capsulorhexis and extracapsular cataract extraction with linear capsulotomy. Acta Ophthalmol Scand 1999; 77:394–6.

5.Ravalico G, Tognetto D, Palomba MA et al. Corneal endothelial function after extracapsular cataract extraction and phacoemulsification.

JCataract Refractive Surg 1997;23:1000–5.

6.Leen MM, Ho CC, Yanoff M. Association between surgically-induced astigmatism and cataract incision size in the early postoperative period. Ophthalmic Surg 1993;24:586–92.

7.Minassian DC, Rosen P, Dart JKG et al. Extracapsular cataract extraction compared with small incision surgery by phacoemulsification: a randomized trial. Br J Ophthalmol 2001;85: 822–9.

8.Jürgens I, Matheu A, Castilla M. Ocular hypertension after cataract surgery: a comparison of three surgical techniques and two viscoelastics. Ophthalmic Surg Lasers 1997;28:30–6.

9.Bömer TG, Lagreze WD, Funk J. Intraocular Pressure Rise after Cataract Extraction – Influence of Surgical Technique, Surgeon’s Experience and Prophylactic Medication. A Prospective, Randomized Double-Blind Study. Klinische Monatsblatter Für Augenheilkunde

1995;206:13–9.

10.Lüchtenberg M, Luchtenberg C, Lang M et al. Intraocular pressure after IOL implantation by using three different types of viscoelastics.

Ophthalmology 2000;97:331–5.

11.Smith SG, Lindstrom RL. 2% Hydroxypropyl methylcellulose as a viscous surgical adjunct. A multicenter prospective randomized trial.

JCataract Refractive Surg 1991;17:839–42.

12.Pedersen OO. Comparison of the protective effects of methylcellulose and sodium hyaluronate on corneal swelling following phacoemulsification of senile cataracts. J Cataract Refractive Surg 1990;16:594–6.

13.Probst LE, Nichols BD. Corneal endothelial and intraocular pressure changes after phacoemulsification with Amvisc Plus and Viscoat. J Cataract Refractive Surg 1993;19:725–30.

14.Rainer G, Menapace R, Findl O et al. Intraocular pressure after small incision cataract surgery with Healon 5 and Viscoat. J Cataract Refractive Surg 2000;26:271–6.

15.Miller KM, Colvard DM. Randomized clinical comparison of Healon GV and Viscoat. J Cataract Refractive Surg 1999;25:1630–6.

16.Koch DD, Liu JF, Glasser DB et al. A comparison of corneal endothelial changes after use of Healon or Viscoat during phacoemulsification. Am J Ophthalmol 1993;115:188–201.

17.Kohnen T, von Ehr M, Schutte E et al. Evaluation of intraocular pressure with Healon and Healon GV in sutureless cataract surgery with foldable lens implantation. J Cataract Refractive Surg 1996;22: 227–37.

18.Arshinoff SA, Hofmann I. Prospective, randomized trial of Microvisc and Healon in routine phacoemulsification. J Cataract Refractive Surg 1997;23:761–5.

19.John ME, Randall LN, Boleyn BA et al. Effect of a superficial and a deep scleral pocket incision on the incidence of hyphema. J Cataract Refractive Surg 1992;18:495–9.

20.Anders N, Pham DT, Wollensak J. Wound Strength in self-sealing cataract surgery depending on the site and the depth of the Incision.

Klinische Monatsblatter Für Augenheilkunde 1995;206:442–5.

21.Dick HB, Schwenn O, Krummenauer F et al. Inflammation after sclerocorneal versus clear corneal tunnel phacoemulsification.

Ophthalmology 2000;107:241–7.

22.Kurimoto Y, Komurasaki Y, Yoshimura N et al. Corneal astigmatism After cataract surgery with 4·1 mm BENT scleral and 4·1 mm plus meridian corneal incisions. J Cataract Refractive Surg 1999;25: 427–31.

23.Cillino S, Morreale D, Mauceri A et al. Temporal versus superior approach phacoemulsification: Short-term postoperative astigmatism.

J Cataract Refractive Surg 1997;23:267–71.

24.Olsen T, Dam Johansen M, Bek T et al. Corneal versus scleral tunnel incision in cataract surgery: a randomized study. J Cataract Refractive Surg 1997;23:337–41.

25.Hunold W, Auffarth GU, Bailitis S et al. No-stitch tunnel incision versus corneoscleral incision. A prospective, randomized study.

Ophthalmology 1995;92:274–9.

26.Gimbel HV, Sun R, DeBroff BM. Effects of wound architecture and suture technique on postoperative astigmatism. Ophthalmic Surg Lasers 1995;26:524–8.

27.Anders N, Pham DT, Antoni HJ et al. Postoperative astigmatism and relative strength of tunnel incisions: a prospective clinical trial. J Cataract Refractive Surg 1997;23:332–6.

28.Bömer TG, Lagreze WD, Funk J. Intraocular pressure rise after phacoemulsification with posterior chamber lens implantation: effect of prophylactic medication, wound closure, and surgeon’s experience. Br J Ophthalmol 1995;79(9):809–13.

29.Kawano K. Modified corneoscleral incision to reduce postoperative

astigmatism after 6 mm diameter intraocular lens implantation.

J Cataract Refractive Surg 1993;19:387–92.

30.Wirbelauer C, Anders N, Pham DT et al. Effect of incision location on

preoperative oblique astigmatism after scleral tunnel incision.

J Cataract Refractive Surg 1997;23:365–71.

31.Mendivil A. Comparative study of astigmatism through superior and lateral small incisions. Eur J Ophthalmol 1996;6:389–92.

32.El Maghraby A, Anwar M, el Sayyad F et al. Effect of incision size on

early postoperative visual rehabilitation after cataract surgery and intraocular lens implantation. J Cataract Refractive Surg 1993; 19:494–8.

33.Grabow HB. Early Results of 500 Cases of No-Stitch cataract surgery.

J Cataract Refractive Surg 1991;17(Suppl):726–30.

34.Martin RG, Sanders DR, Miller JD et al. Effect of cataract wound incision size on acute changes in corneal topography. J Cataract Refractive Surg 1993;19(Suppl):170–7.

35.Olson RJ, Crandall AS. Prospective randomized comparison of phacoemulsification cataract surgery with a 3·2-mm v a 5·5-mm sutureless incision. Am J Ophthalmol 1998;125:612–20.

36.Levy JH, Pisacano MD, Chadwick BS. Astigmatic changes after cataract surgery with 5·1 mm and 3·5 mm sutureless incisions. J Cataract Refractive Surg 1994;20:630–3.

37.Mendivil A. Intraocular lens implantation through 3·2 versus 4·0 mm incisions. J Cataract Refractive Surg 1996;22:1461–4.

38.Gimbel HV, Raanan DG, DeLuca M. Effect of suture material on postoperative astigmatism. J Cataract Refractive Surg 1992;18:42–50.

39.Dam-Johansen M, Olsen T. Induced astigmatism after 4 and 6 mm scleral tunnel incision. A randomized study. Acta Ophthalmo Scand 1997;75:669–74.

40.Davison JA. Keratometric comparison of 4·0 mm and 5·5 mm scleral tunnel cataract incisions. J Cataract Refrac Surg 1993;19:3–8.

41.Oshika T, Tsuboi S, Yaguchi S et al. Comparative study of intraocular lens implantation through 3·2 and 5·5 mm incisions. Ophthalmology 1994;101(7):1183–90.

42.Hayashi K, Hayashi H, Nakao F et al. The correlation between incision size and corneal shape changes in sutureless cataract surgery.

Ophthalmology 1995;102:550–6.

43.Diestelhorst M, Dinslage S, Konen W et al. Effect of 3·0 mm tunnel and 6·0 mm corneoscleral incisions on the blood–aqueous barrier.

J Cataract Refractive Surg 1996;22:1465–70.

44.Kohnen T, Dick B, Jacobi KW. Comparison of the induced astigmatism after temporal clear corneal tunnel incisions of different sizes. J Cataract Refractive Surg 1995;21:417–24.

45.Dick HB, Kohnen T, Jacobi FK, Jacobi KW. Long-term endothelial cell loss following phacoemulsification through a temporal clear corneal incision. J Cataract Refractive Surg 1996;22:63–71.

46.Holweger RR, Marefat B. Corneal changes after cataract surgery with 5·0 mm sutured and 3·5 mm sutureless clear corneal incisions. J Cataract Refractive Surg 1997;23:342–6.

47.Kosrirukvongs P, Slade SG, Berkeley RG. Corneal endothelial changes after divide and conquer versus chip and flip phacoemulsification.

J Cataract Refractive Surg 1997;23:1006–12.

48.Kohlhaas M, Klemm M, Kammann J et al. Endothelial cell loss after phacoemulsification – a comparison between the “Reversed Tip and Snip” technique and “Divide and Conquer” technique. Klinische Monatsblatter Für Augenheilkunde 1997;210(2):82–5.

49.Wong T, Hingorani M, Lee V. Phacoemulsification time and power requirements in phaco chop and divide and conquer nucleofractis techniques. J Cataract Refractive Surg 2000;26:1374–8.

50.Alio J L, Mulet ME, Garcia JC. Use of cyanoacrylate tissue adhesive in small-incision cataract surgery. Ophthalmic Surg Lasers 1996; 27:270–4.

51.Mendivil A. Frequency of induced astigmatism following phacoemulsification with suturing versus without suturing.

Ophthalmic Surg Lasers 1997;28(5):377–81.

52.Lyhne N, Corydon L. Astigmatism after phacoemulsification with adjusted and unadjusted sutured versus sutureless 5·2 mm superior scleral incisions. J Cataract Refractive Surg 1996;22:1206–10.

53.El Kasaby HT, McDonnell PJ, Deutsch J. Videokeratography: a comparison between 6 mm sutured and unsutured incisions for phacoemulsification. Eye 1995;9:719–21.

54.Lyhne N, Corydon, L. Two year follow up of astigmatism after

phacoemulsification with adjusted and unadjusted sutured versus sutureless 5·2 mm superior scleral incisions. J Cataract Refract Surg 1998;24:1647–51.

55.Azar DT, Stark WJ, Dodick J et al. Prospective, randomized vector analysis of astigmatism after three-, one-, and no-suture phacoemulsification. J Cataract Refractive Surg 1997;23:1164–73.

56.Mendivil A. Effect of nylon suture diameter on induced astigmatism after phacoemulsification. J Cataract Refract Surg 1997;23: 1196–9.

57.Blaydes JE, Berry J. A comparative evaluation of 9-0 monofilament and 9-0 braid polyglactin 910 in cataract surgery (intracapsular, extracapsular, and phacoemulsification). Ophthalmic Surg 1979;10:49–54.

58.Mester U, Zuche M, Rauber M. astigmatism after phacoemulsification with posterior chamber lens implantation: small incision technique with fibrin adhesive for wound closure. J Cataract Refractive Surg 1993;19:616–9.

59.Mulet Homs ME, Alio Y, Sanz JL et al. Efficacy of fibrinogen as bioadhesive in cataract surgery through scleral tunnel. Archivos De La Sociedad Espanola De Oftalmologia 1997;72:427–30.

60.Meacock WR, Chittenden H, Govan J. Conjunctival wound closure by saline injection in sutureless, scleral tunnel incision phacoemulsification. J Cataract Refractive Surg 1996;22:1240–1.