Phacoemulsification Versus Endocapsular Cataract Extraction in a Unique Cohort of Patients

PHACOEMULSIFICATION VERSUS ENDOCAPSULAR CATARACT EXTRACTION IN A UNIQUE COHORT OF PATIENTS

T. POTAMITIS\ s. BEATTY\ A. M. PEREIRAl and J. L. PEARCE2 Birmingham and Redditch

SUMMARY indications have been discussed elsewhere.5,6 It is not

The visual recovery and refractive results of 33 routinely performed in the developed world and consecutive patients (66 eyes) undergoing standard consequently it has not been possible to compare the endocapsular cataract extraction in one eye and visual and refractive outcomes of PE and ECCE in simultaneous phacoemulsification in the fellow eye the same patient over a single period of convales are reported. One surgeon performed all the opera cence. In our study all surgery was performed by one tions. Surgically induced astigmatism was evaluated for surgeon (J.L.P.) who is a strong advocate of SBCE. the two techniques in terms of: (1) the proportion of We reviewed the visual and refractive results of 33 eyes with a refractive cylinder of 1.5 dioptres (D) or patients undergoing bilateral cataract extraction at less; (2) the interocular difference in post-operative one sitting. In each case one eye was arbitrarily astigmatism. Eyes undergoing phacoemulsification had assigned to undergo PE and the other eye conven a significantly lower mean induced cylinder (paired tional ECCE. The results are compared for the two Student's t-test: t = 3.729; plens opacities; fitnessfor general anaesthesia confirm the beneficial effects of phacoemulsification on (in no case was simultaneous bilateral cataract astigmatism and visual outcome in the early post extraction performed under a regional block); operative period. proceeding to operate on the second eye only if the first was free of serious complications such as Phacoemulsification (PE) is rapidly becoming the posterior capsule rupture with vitreous loss or preferred technique of cataract extraction for many expulsive haemorrhage. Patients with a predisposi ophthalmic surgeons. The speed of visual rehabilita tion to ocular infection (blepharitis, atopic eczema, tion and the reduced post-operative astigmatism trichiasis) or intraocular pathology that might pro associated with this technique are the main factors long the procedure (posterior synechiae, pseudoex contributing to the transition from conventional foliation) are excluded. Pre-operative biometry was extracapsular cataract extraction (ECCE).l-4 performed routinely, and in every case emmetropia Simultaneous bilateral cataract extraction (SBCE) was the desired post-operative refraction. is a controversial subject and its risks, benefits and Data were retrieved from hospital records and all patients were reviewed and underwent refraction I From: Birmingham and Midland Eye Centre. Birmingham; 2 and keratome try by one of the authors. Astigmatism Alexandra Hospital, Redditch, UK. Correspondence to: T. Potamitis, Birmingham and Midland was expressed in terms of plus cylinder. Visual Eye Centre, Dudley Road, Birmingham B18 7QH, UK. recovery was assessed using the unaided visual acuity

• Phacoemulslflcatlon • ECCE

40 % 30

o 6/36 & 6/60 6/18 & 6/24 6/9&6/12 6/6 or better

Fig. 1. Unaided visual acuity 1 week post-operatively. at 1 and 8 weeks post-operatively and corrected intraocular lens (IOL) inserted. The anterior capsu visual acuity at the time of the last assessment. In lotomy was then completed. The wound was sutured addition, every patient was asked if they had a with a continuous 10-0 nylon suture and all the preference for either eye in terms of visual recovery. sodium hyaluronate aspirated from the anterior In our analysis of visual outcomes and ocular chamber. preference, patients with functional visual disability Phacoemulsification Surgery. A 3.2 mm biplanar not fully accounted for by cataract formation were incision was made in temporal clear cornea and excluded. sodium hyaluronate injected into the anterior cham We used the paired Student's t-test, the chi ber. A manual capsulorhexis was performed and this squared test (with Yates' correction where appro was followed by hydrodissection of the lens. The priate), Wilcoxon's signed rank test and McNemar's nucleus was phacoemulsified in the posterior cham test in our statistical analysis. ber using the 'divide and conquer' technique. Cortical clean-up was achieved by irrigation with Surgical Technique balanced salt solution and automated aspiration. The capsular bag was filled with sodium hyaluronate and Conventional Extracapsular Surgery. An 8-10 mm after extending the incision a 5.5 mm optic one-piece superior limbal incision was made and sodium PMMA IOL was inserted. The wound was not hyaluronate injected into the anterior chamber. An sutured and the sodium hyaluronate was aspirated envelope capsulotomy was then performed. The from the anterior chamber at the end of the nucleus was expressed using the bimanual technique. procedure. Cortical clean-up was achieved using the co-axial irrigation-aspiration manual system. Sodium hyalur onate was then injected into the bag and a 7 mm RESULTS optic one-piece polymethylmethacrylate (PMMA) Post-operative follow-up ranged from 24 to 53 weeks

• Phacoemulsification • ECCE

40 % 30

o 6/36 & 6/60 6/18 & 6/24 6/9 & 6/12 6/6 or better

Fig. 2. Unaided visual acuity 8 weeks post-operatively. PHACOEMULSIFICATION VS ENDOCAPSULAR SURGERY 553

• Phacoemulslfication • ECCE

40 % 30

10 o +---�"�"""� 6/36 & 6/60 6/18 & 6/24 6/9 & 6/12 6/6 or better

Fig. 3. Best corrected final visual acuity.

(mean 35 weeks). Two patients were lost to follow of eyes undergoing PE achieved a corrected Snellen up after the 4 week post-operative visit and were acuity of 6/6 or better (17 PE eyes, 9 ECCE eyes; therefore excluded. Coexisting ocular pathology was pmacular degeneration. These eye. patients were therefore excluded from our analysis Thirty-one pairs of eyes were considered in our of visual recovery. No intra- or post-operative analysis of post-operative astigmatism. Of these, the complications were recorded. PE eye had less astigmatism than the ECCE eye in

One week post-operatively an unaided visual 25 cases (80.5%; Wilcoxon's signed rank test: T = 92; acuity of 6/12 or better was achieved in 14 of 28 PE p<0.01). An interocular difference in post-operative eyes (50%) compared with 9 of the paired eyes which corneal cylinder of more than 1 D was seen in 21 underwent ECCE (32.1%) (Fig. 1). This difference patients. In this group, the eye with the higher did not reach statistical significance (McNemar's test: cylinder had undergone PE in 4 cases and ECCE in

p>0.3). By the eighth post-operative week this level 17 cases (X2 = 16.29; p<0.001). of uncorrected acuity was recorded in 19 (67.8%) of The mean post-operative cylinder for PE was the PE eyes and 16 (57.1%) of the ECCE eyes significantly lower than for ECCE (PE, 1.24 ± (p>0.3) (Fig. 2). 0.833 D; ECCE, 2.21 ± 1.27 D; paired Student's t

A best corrected finalvisual acuity of 6/12 or better test: t = 3.729; p0.3). However, a significantly higher proportion the ECCE group (10 eyes; 32.2%) than among eyes

� Phacoemulsificatlon

• ECCE

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Fig. 4. Post-operative corneal cylindrical error without regard to axis for paired PE and ECCE eyes. 554 T. POTAMITIS ET AL. undergoing PE (22 eyes; 70.9%) (McNemar's test: was significantly higher among eyes undergoing p<0.05) (Fig. 4). ECCE than among those operated on using the PE technique. The reduced astigmatism found among DISCUSSION phacoemulsified eyes is in agreement with previous Several factors influence visual outcome and patient reports2,3 and probably reflects the smaller size of the satisfaction following cataract surgery. These may be incision associated with this technique.1,lO divided into independent predictors of visual out In conclusion, the beneficial effects of phacoemul come, disease-specific factors and generic health sification on astigmatism and visual outcome in the status measures. Disease-specific factors are those early post-operative period are confirmed in this directly related to the lens opacity such as Snellen unique cohort of patients. visual acuity, functional impairment related to vision and cataract symptom score. Generic health-status Key words: Astigmatism, Cataract surgery, Endocapsular, Phacoemulsification. measures comprise broad dimensions of health related quality of life such as physical, emotional REFERENCES and social functioning. Finally, independent predic 1. Neumann AC, McCarty GR, Sanders DR, Raanan tors of visual outcome include age and ocular MG. Small incisions to control astigmatism during comorbidity?,8 In our study variability between cataract surgery. J Cataract Refract Surg 1989;15: subjects is eliminated and thus all the above factors 78-84. are controlled. In addition, the viewing distance and 2. Watson A, Sundenaj P. Comparison of small-incision level of illumination under which visual acuity is phacoemulsification with standard extracapsular catar act surgery: post-operative astigmatism and visual tested are identical for paired eyes. recovery. Eye 1992;6:626-9. It is not the aim of this paper to argue for or 3. Dam-Johansen M, Olsen T. Refractive results after against SBCE but to provide a unique comparison of phacoemulsification and ECCE: a comparative study. two different types of cataract surgery. Previous Acta Ophthalmol (Copenh) 1993;71:382-7. investigators have evaluated the visual and refractive 4. Wishart PK, Austin MW. Combined cataract extrac tion and trabeculectomy: phacoemulsification com results of PE and ECCE but not in the same patient pared with extracapsular technique. Ophthalmic Surg over a single period of time. Consequently, matched 1993;24:814-21. pairs of eyes have not been studied and previous 5. Benezra D, Chirambo Me. Bilateral versus unilateral comparisons have been made only in terms of cataract extraction: advantages and complications. Br J disease-specificfactors. OphthalmoI1978;62:770-3. 6. Beatty S, Aggarwal RK, David DB, Guano M, Jones In our study uncorrected visual recovery was R, Pearce JL. Simultaneous bilateral cataract extrac similar for the two groups. This has not been the tion in the UK. Br J OphthalmoI1995;79:1111-4. experience of other workers.L2,4 A statistically 7. Damiano AM, Steinberg EP, Cassard SD, Bass EB, similar proportion of PE and ECCE eyes achieved Diener-West M, Legro MW, et al. Comparison of a satisfactory best corrected finalvisual acuity of 6/12 generic versus disease-specific measures of functional impairment in patients with cataract. Med Care or better, and our results are comparable to reports 1995;33:120-30. in the literature.9 However, an excellent final 8. Schein OD, Steinberg EP, Cassard SD, Tielsch JM, corrected visual acuity of 6/6 or better was signifi Javitt JC, Sommer A. Predictors of outcome in patients cantly more common among phacoemulsified eyes. who underwent cataract surgery. Ophthalmology This is consistent with the results of previous 1995;102:817-23. 9. Powe NR, Schein OD, Gieser SC, Tielsch JM, Luthra investigators,2 and is reflected in the greater patient R, Javitt J, Steinberg EP. Synthesis of the literature on satisfaction associated with this technique. visual acuity and complications following cataract We recorded less astigmatism in PE eyes 24-53 extraction with intraocular lens implantation. Arch weeks post-operatively than in their fellow eyes Ophthalmol 1994;112:239-52. which underwent simultaneous conventional ECCE. 10. Levy JR, Pisacano AM, Chadwick K. Astigmatic changes after cataract surgery with a 5.1 mm and The mean post-operative cylinder and the proportion 3.5 mm sutureless incisions. J Cataract Refract Surg of eyes with corneal astigmatism greater than 1.5 D 1994;20:630-3.