Delta Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 19  |  Issue : 2  |  Page : 92--98

Phacoemulsification versus manual small incision cataract surgery in hard nuclear cataracts


Hesham A Enany 
 Department of Ophthalmology, Faculty of Medicine, Zagazig University, Zagazig, Egypt

Correspondence Address:
Hesham A Enany
Ophthalmology, Department of Ophthalmology, Faculty of Medicine, Zagazig University, Zagazig 44519
Egypt

Abstract

Purpose The aim of this study was to compare the clinical outcomes of phacoemulsification with that of manual small incision cataract surgery (MSICS) in cases of hard nuclear cataract. Patients and methods Eighty eyes of 80 patients with gradual painless diminution of vision, diagnosed as senile nuclear cataract grade 4 or higher according to Lens Opacities Classification System III (brown cataract), were studied. These eyes were divided randomly into two groups: group A included 40 eyes treated by phacoemulsification by the vertical chopping technique and group B included 40 eyes treated by MSICS by the viscoexpression technique. Results One day postoperatively, the corrected distance visual acuity was at least 6/18 in 21 (52.5%) patients in the MSICS group and in nine (22.5%) patients in the phacoemulsification group. The difference was statistically significant (P=0.01). A postoperative increase in intraocular pressure was recorded in one (2.5%) case in the phacoemulsification group. On the first postoperative day, 11 (27.5%) cases in the MSICS group and 13 (32.5%) cases in the phacoemulsification group developed postoperative iritis, with no statistically significant difference between both the groups. Conclusion Both phacoemulsification and MSICS achieved comparable and excellent visual outcomes for treatment of hard brown cataract, with lower complications rates and earlier postoperative visual rehabilitation in small incision cataract surgery.



How to cite this article:
Enany HA. Phacoemulsification versus manual small incision cataract surgery in hard nuclear cataracts.Delta J Ophthalmol 2018;19:92-98


How to cite this URL:
Enany HA. Phacoemulsification versus manual small incision cataract surgery in hard nuclear cataracts. Delta J Ophthalmol [serial online] 2018 [cited 2018 Aug 17 ];19:92-98
Available from: http://www.djo.eg.net/text.asp?2018/19/2/92/233930


Full Text



 Introduction



The main objective in modern cataract surgery is to achieve a better unaided visual acuity with a rapid postsurgical recovery and reduced intraoperative and postoperative complications [1].

Hard brown cataract is a risk factor for intraoperative complications during phacoemulsification in the hands of surgeons who deal with such cataract occasionally. It is still a challenge for experienced surgeons. The chances of conversion into extracapsular cataract extraction (ECCE) are higher than soft and medium-hard nuclei because of the damage to intraocular tissues produced by surgical trauma during emulsification of hard and large nuclei [2].

Phacoemulsification has become the routine procedure for cataract extraction in the developed countries, where rehabilitation of the patient is very fast, associated with good visual outcomes. It offers the advantages of faster and more predictable wound healing, reduced discomfort to patients, fewer wound complications, and less changes of postoperative astigmatism than conventional ECCE [3].

Modern ECCE surgery involves removal of the lens fibers, which form the nucleus and cortex of the cataract, leaving the posterior epithelial capsule to hold the new artificial intraocular lens (IOL) and keep the vitreous humor away from the anterior chamber. Extracapsular techniques of cataract extraction surgery originally involved manual nuclear expression. Phacoemulsification is a mechanically assisted extracapsular technique of cataract extraction surgery [4].

Manual small incision cataract surgery (MSICS) is characterized by early wound stability, less postoperative inflammation, no suture-related complications, few postoperative visits, and less damaging effect on the corneal endothelium. Moreover, MSICS can be performed in almost all types of cataract in contrast to phacoemulsification, where case selection is extremely important for junior surgeons [5].

Studies on normal population to assess the response of the endothelium to cataract surgery have shown a decrease in the endothelial density over a 3-month period postoperatively with an increase in the coefficient of variation and decrease in the percentage of hexagonal cells [6].

In developing countries such as India and Egypt, where there is a cataract backlog, MSICS with IOL implantation promises to be a viable cost-effective alternative to phacoemulsification [7]. In Egypt, MSICS is less dependent on technology; hence, it is less expensive and more appropriate for the treatment of advanced cataracts [8].

The aim of this study was to compare the clinical outcomes of phacoemulsification with that of MSICS in cases with hard nuclear cataracts.

 Patients and methods



Eighty eyes of 80 patients were chosen from the outpatient clinic of the Ophthalmology Department at Zagazig University Hospitals. These patients had gradual painless diminution of vision, diagnosed as senile nuclear cataract grade 4 or higher according to Lens Opacities Classification System III (brown cataract) [9]. The eyes were divided randomly into two groups: group A included 40 eyes treated by phacoemulsification by the vertical chopping technique and group B included 40 eyes treated by MSICS by the viscoexpression technique.

Exclusion criteria

Patients younger than 40 years, with dislocated and subluxated lenses, corneal diseases (congenital anomalies, degeneration, dystrophies, peripheral thinning, and conditions with a low endothelial count), ocular inflammations such as scleritis, patients with chronic open-angle glaucoma, poorly dilated pupils, a history of previous intraocular surgeries, and systemic disorders such as bleeding disorders were excluded from the study.

Preoperative examination

The history obtained from the patients included name, age, sex, history of any medical disease, especially diabetes and hypertension, and a history of any previous operation (ocular or systemic). A careful ophthalmologic examination was performed for each case in the form of measurement of distance visual acuity, slit-lamp examination for assessment of the cornea, anterior chamber depth, regularity of the pupil, nuclear hardness, measurement of intraocular pressure using a Goldmann applanation tonometer, and measurement of keratometric readings. After pupillary dilatation, nuclear grading was performed according to Lens Opacities Classification System III and fundus examination was performed using a +20 D lens for indirect ophthalmoscopy and a +90 D lens for slit-lamp fundus biomicroscopy if possible to exclude any retinal pathology. A-scan to measure the axial length and keratometry to measure the corneal refractive power were performed for IOL power calculation using the SRK II formula [P=A1−BL−CK, where P is the implant power for emmetropia, L is the axial length (mm), K is the average keratometry, and A, B, and C are constants] and B-scan ultrasonography was performed to evaluate the posterior segment if it was could not be visualized properly because of the dense cataract.

This was followed by measurement of central corneal thickness. Dual-scanning corneal tomography (Sirius System; Costruzione Strumenti Oftalmici, Firenze, Italy) and specular microscopy (Topcon Specular microscope, Sp-2000P; Topcon Inc., Tokyo, Japan) (endothelial images) were performed at baseline (preoperatively) and postoperatively at 1 and 8 weeks. All parameters were tabulated. Comparison of mean changes in the central corneal thickness, cell density, coefficient of variation, and SD; both within and between groups, 1 and 8 weeks; as compared to baseline were performed with 95% level of significance (P<0.05).

Pupillary dilatation was performed by topical administration of phenylephrine hydrochloride 2.5% eye drops and cyclopentolate hydrochloride 1% eye drops.

Both operative procedures were performed under local anesthesia by the ophthalmologist. Surface anesthetic, benoxinate 0.4% eye drops, was administered once just before the operation.

Surgical techniques

Group A included 40 eyes treated by phacoemulsification by the vertical chopping technique as shown in [Figure 1].{Figure 1}

Group B included 40 eyes treated by MSICS by the viscoexpression technique as shown in [Figure 2]. The conjunctiva was closed by cauterization at the end of surgery.{Figure 2}

Follow up

Patients were examined on the first postoperative day, and after 1, 2, 4, and 8 weeks.

Statistical analysis

SPSS 13.0 (SPSS Inc., Chicago, Illinois, USA) was used. The independent-samples t-test and χ2 were used. The test was considered significant if P is less than 0.05, highly significant if P is less than 0.01, and not significant if P is more than 0.05.

The procedures followed were in accordance with the ethical standards of the institutional review board (IRB). Approval of IRB and informed consent from adult participants were obtained.

 Results



Eighty patients undergoing cataract surgery were included in this study. Patients were divided into two groups: group A included those patients who underwent phacoemulsification and group B included those patients who underwent MSICS ([Table 1]).{Table 1}

Intraoperative complications in both groups were recorded. The difference between both groups in failed continuous curvilinear capsulorhexis (CCC) was insignificant (P=0.08), whereas the difference in posterior capsule rupture (PCR) (P=0.021) and conversion to ECCE was significant (P=0.001) ([Table 2]).{Table 2}

The difference between both groups in postoperative corneal edema, by slit-lamp and specular microscopy and Sirius dual-scanning corneal tomography according to corneal thickness, in 1 and 8 weeks was insignificant (P=0.369, [Table 3]).{Table 3}

A postoperative increase in the intraocular pressure was recorded in one (2.5%) case in the phacoemulsification group.

Postoperative iritis was observed on the first postoperative day in 11 (27.5%) cases in the MSICS group and 13 (32.5%) cases in the phacoemulsification group, a statistically insignificant difference (P=0.258, [Table 4]).{Table 4}

The mean difference in central corneal thickness at baseline and at 1 week postoperatively, between groups A and B, was statistically significant (P=0.024). However, the difference between the baseline value and the 8- and 1-week with 8-week was not statistically significant ([Table 5]).{Table 5}

The difference between both groups in cell density at 1 and 8 weeks was insignificant (P>0.05, [Table 6]). The mean coefficient of variation and the mean±SD between groups were also not statistically significant (P>0.05, [Table 7]).{Table 6}{Table 7}

One day postoperatively, the corrected distance visual acuity was at least 6/18 in 21 (52.5%) patients in the MSICS group and nine (22.5%) patients in the phacoemulsification group; the difference was statistically significant (P=0.01, [Table 8]).{Table 8}

 Discussion



MSICS is comparable to phacoemulsification for the rehabilitation of the patient with cataract. It is recommended as an alternative to phacoemulsification wherever the required equipment and experience are not available. A hard brown cataract is a well-known risk factor for intraoperative complications during phacoemulsification.

Venkatesh et al. [10] reported that both surgical techniques achieved good visual outcomes and both groups had a comparable corrected distance visual acuity of at least 6/18 2 months postoperatively (92.5 vs. 85%, P=0.36). In the present study, uncorrected distance visual acuity of at least 6/18 2 months postoperatively was achieved in 85 and 75% of the patients, respectively. Gogate et al. [11] reported that both phacoemulsification and small incision techniques were safe and effective for visual rehabilitation of cataract patients, although phacoemulsification yields better uncorrected visual acuity in a larger population of patients at 6 weeks.

In the present study, the common complication rates were statistically significantly higher in the phacoemulsification group than in the MSICS group (15 vs. 25%, respectively). Haripriya et al. [12] analyzed the rate of intraoperative complications, reoperations, and endophthalmitis with phacoemulsification, MSICS, and large-incision ECCE, and they concluded that for staff surgeons experienced with both phacoemulsification and MSICS, intraoperative complication rates were comparably low.

In the present study, the major intraoperative complications in MSICS and phacoemulsification were PCR (5 vs. 12.5%, respectively), failed CCC (7.5 vs. 10%, respectively), and wound burn (0 vs. 12.5%, respectively); these were statistically nonsignificant. Muhtaseb et al. [13] assessed the risk factors for intraoperative complications during phacoemulsification and found that hard brown cataract is a well-known risk factor for PCR, vitreous loss, failed CCC, zonular dialysis, lost nucleus, and wound burn.

In the present study, conversion to ECCE was recorded in 20% of phacoemulsification cases. Ali et al. [14] reported a conversion rate in phacoemulsification cases of 1.67%, whereas Dada et al. [2] reported a conversion rate in phacoemulsification cases of 3.7%. The reason for this higher rate of conversion to ECCE was the nature of this hard brown cataract, which makes the nucleus management more difficult and risky.

In the present study, MSICS yielded better successful visual results than phacoemulsification (i.e. ≥6.18) in a larger proportion of patients 1 day postoperatively (52.5 vs. 22.5%, respectively). The success rate correlated with the absence of severe corneal edema (5 vs. 25%, respectively). Venkatesh et al. [10] showed that the MSICS group had less corneal edema than the phacoemulsification group on the first postoperative day in cases with white cataract.

Previous studies reported no significant difference in endothelial cell loss among conventional ECCE, MSICS, and phacoemulsification groups [15].

In the current study, the mean difference in central corneal thickness at baseline, 1, and 8 weeks was not statistically significant. In addition, the mean coefficient of variation and the mean±SD between both groups were not statistically significant.

El-Sayed et al. [8] reported both phacoemulsification and MSICS achieved excellent visual outcomes with low complication rates. MSICS is less dependent on technology. Hence, it is less expensive and more appropriate for the treatment of advanced cataracts prevalent in the developing countries.

One of the limitations of this study was that only one technique of phocoemulsification and one technique of MSICS were compared. Other techniques may yield different results. Another major limitation of the present study was the short-term follow-up (8 weeks). However, a prospective study from the USA evaluating the long-term safety (5 years) of phacoemulsification found that the rate of endothelial cell loss decreases over time [16].

Both MSICS and phacoemulsification yielded excellent results, both anatomical and refractive. However, MSICS appears to be more advantageous than phacoemulsification in terms of speed, cost, and independence from technology, and appears to more suitable for dense cataracts and mass surgery [17].

 Conclusion



Phacoemulsification and MSICS achieve comparable and excellent visual outcomes in dealing with hard brown cataract, with lower complication rates and earlier postoperative visual rehabilitation in MSICS.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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