A Comparative Study of Anatomic and Functional Outcomes of Two Surgical Techniques of Cataract at Lome

Results: At the 45th postoperative day, 60% of operated eyes of the ECCE group (G1) and 83.9% in the group of MSICS (G2) had uncorrected visual acuity greater than or equal to 3/10. Through the pinhole, these proportions increased to 73.3% for G1 and 92.2% for G2. Visual acuity was less than 1/10 in 4.4% for G1 and 1.1% for G2. The vitreous loss was observed in proportions of 3.8% for G1 and 3.3% for G2. During follow-up, the three main early postoperative complications were infl ammation (13.9%), corneal edema (13.3%), and the pigment dispersion (7.2%) in G1 and corneal edema (9.4%), pigment dispersion (8.3%) and hypertonia (6.6%) in G 2.


INTRODUCTION
Cataract is a partial or total clouding of the lens that causes decrease of visual acuity (DVA). Its main causes are senescence, intraocular in lammation, metabolic troubles, trauma, and radiations.
According to WHO, cataract is the irst cause of blindness in the world [1]. It is 50% of all of avoidable blindness causes. Developing countries pay a heavy price of that problem. Surgery is the only one treatment currently available. Cataract surgery techniques have improved considerably from intracapsular extraction, phacoemulsi ication surgery and Laser femtosecond surgery. The last gives well anatomical and functional results, but it is still a very expensive procedure for developing countries. These last decades, a new technique has emerged almost taking the phacoemulsi ication without the use of ultrasound [2]. It is the surgical technique of cataract by manual sutureless small incision cataract surgery (MSICS). This technique also gives well anatomical and functional results [2][3][4][5][6][7][8].
MSICS is recently introduced in Togo and has been more and more widely used since 2010. In a previous study, the astigmatism has been evaluated in cataract surgery by MSICS [9]. The purpose of this study was to compare the anatomical and functional results of cataract surgery by MSICS to those of extracapsular cataract extraction (ECCE) with suture in Lome. To be eligible each patient must give an informed consent. He or she had to be at least 40 years old and have no history of ocular pathology that can lead to the decreased of visual acuity (DVA) apart from cataract. Therefore, patients with a pterygium, a corneal scar or macular disease, optic atrophy were excluded. Each patient must be operated by the same surgeon in the same eye center in the same conditions and have to follow-up postoperative control appointments until the forty-ifth day. Any patient were prepared as follow for the surgery: The implants inserted were of standard power of 21 or 22 diopters depending on what was available since no implant power calculation was made prior to surgery. In each group there was no hospital stay. The follow up was made regularly by the team. The team reported any complication to the surgeon for it management. The post operative medication was topical corticosteroid mixed with antibiotic during 30 days.

PATIENTS AND METHODS
The studied variables were age, sex, visual acuity assessed in a well-light room using a Snellen scale placed at 5 meters, and incidents per operative and postoperative complications. The encountered dif iculties were related to the study framework which was not yet available for biometer computation power of the intraocular lens.
Data collected on a standardized plug were analyzed using Epi Info version 6.0 software. The results are presented as averages and statistical Chi 2 test has been used with a threshold of signi icance P<0, 05.

RESULTS
In each group there were 180 operated eyes, totaling 360 operated eyes of 360 patients. The female sex was more represented in each group 103 and 119 with a sex ratio of 0.75 and 0.51 respectively in G1 and G2 (Table 1). Table 2 summarizes the distribution of patients by age. The most represented age groups were those above 70 years (G1) and 61 to 70 years (G2). No patient was left aphakic. Uncorrected visual acuity (UVA) of preoperative ( Figure 1) was less than 1/10 in 96% in G1 and 90.5% in G2. The difference between the two groups was not signi icant (p=0.8390). Intraoperative, vitreous loss occurred in 7 cases in G1 (3.8%) and 6 cases in G2 (3.3%).

DISCUSSION
In order to evaluate the new surgical cataract technique (MSICS) which is a variant of ECCE sutureless, a prospective, monocentric, descriptive and analytical study has been conducted. This methodology has also been used by some authors either to be compared to MSICS or ECCE with phacoemulsi ication [3,5,8,9,[11][12][13][14].
In our study keratometry before and after the operation was not carried because of the lack of equipment. This does not allow us to evaluate the surgically induced astigmatism. Astigmatism is a complication of cataract surgery that can in luence functional results [5][6][7][8][9]15]. Another limit of our study is the non-computation of implant power for the same reason as before. Thus, patients have been implanted in posterior chamber with rigid implants PMMA power ranging from 21 to 22 diopters. This situation can make our postoperative functional outcomes probably underestimated.
Visual acuity on D45 does not re lect the inal visual acuity of the operated eye especially with ECCE, which requires suf icient perspective to stabilize the astigmatogen effect of sutures. Some authors evaluated visual acuity 6 or 12 weeks postoperative [4,5,8,[11][12][13][14][15][16]. The ablation of sutures was done on D30 of postoperative in G1. Control on D45 allowed to evaluate visual acuity in both groups. In conditions that were familiar to us, the two techniques were compared in order to determine the best new operative technique to be used in future cataract surgeries in our developing country.
We noted a female predominance in both groups of the study. This observation reinforces the trend generally reported by several authors [5,7,[17][18][19]. Lind ield et al. [20] also observed in a multicentre study in Kenya, Philippines and Bangladesh that more women undergo cataract surgery than men. Women are prevalent in each study group because they have a higher life expectancy than men according to updated data from the general direction of statistics and population in Togo.
In our study, UVA preoperative ( Figure 1) was less than 1/10 in 96% in Group 1 and 90.5% in Group 2. Gogate et al. [8] reported that the UVA was less than 1/10 in 85.8% in the group of manual small incision cataract surgery (MSICS) equivalent of MSICS and 87.5% in that of ECCE. Venkatesh et al. [21] observed that 88.5% of the patients of their series were operated at the stage of VA less than 1/10. In a study in the United Kingdom percentage of patients operated for cataract at VA less than 1/10 decreased by 15% in 1997 to 1.6% in 2000 and inally to 0% in 2008 [22]. This can be explained by the improvement of technical conditions for carrying out the cataract surgery in line with requirements for visual performance of the population. This context has promoted upward revision of preoperative VA threshold. With MSICS, it will be possible to operate a cataract to a higher VA to 1/10 if the patient is very plaintiff with a guarantee of anatomical and functional results in our countries with limited resources.
The main operative incident reported in our study is the vitreous loss in 3.8% and 3.3% respectively in groups 1 and 2. Our results are slightly lower than the 5% recommended by WHO [23]. Both techniques have the same risk of vitreous loss. This observation was also made by Gogate et al. [8] but with frequencies of 1.56% and 1.67% respectively in the group of MSICS and in that of ECCE on samples of 383 and 358 eyes. In India, George et al. [11], as Gurung et al. [12], in Nepal reported no vitreous loss in both surgical techniques. But it should be noted that the sizes of their samples were 124 and 88 respectively for the two eyes combined techniques.
MSICS gave a better pinhole VA in our series with a statistically signi icant difference ( Figure 5). WHO [23] recommended after cataract surgery, there is less than 5% with a pinhole VA less than 1/10 and the pinhole VA is greater than 3/10 in the least 90%. MSICS better meets the WHO recommendations in our series. Gogate et al. [24] reported 1.7% and 1.1% respectively in MSICS and ECCE in Kenya, Trivedy [25] found that 81.8% of the operated had an UVA greater than or equal to 3/10 in a sample of 368 eyes operated with MSICS. Other authors have also observed that MSICS provides early better visual acuity compared to ECCE [3,11,12]. But most of clinicians have also shown that the gap narrows and becomes less signi icant when we consider the corrected VA.
Early complications were dominated in our series by corneal edema and in lammation (iridocyclitis). It is a transitory edema whose frequencies are slightly higher in the ECCE group than in MSICS respectively of 13.3% and 9.4%. Gurung et al. [12] also met more corneal edema in their group of ECCE than in the one of MSICS, but with high frequencies of 62% and 48%. We think that the surgeon's experience has also contributed to the quality of our results. Iridocyclitis in our series was more recurrent in ECCE in such MSICS as noted by Gogate et al. [8] but with a statistically not signi icant. The occurrence of this in lammation causes a lengthening of topical corticosteroid therapy with increase in the overall cost of cataract surgery. Our study also showed further that MSICS generates slightly less clouding of the posterior capsule than ECCE with 6.1% against 8.3%. Ang et al. [7] have observed no difference between the two techniques either 1.1% or 0.8%.

CONCLUSION
At the end of this prospective study that compared the extracapsular cataract extraction (ECCE) to the manual sutureless small incision cataract surgery (MSICS), we noted that both techniques offer the same security level because they have the same intraoperative period risk of vitreous loss. In postoperative period, ECCE gives more in lammation than MSICS, which could increase the inal cost of cataract treatment. MSICS gives better uncorrected visual acuities compared to ECCE six weeks after surgery. This is an advantage in developing countries where the majority of patients does not have the means to afford the optical corrections after the operation. MSICS gives less secondary cataracts than ECCE. This is an advantage in eye centers in developing countries, where the ndYag laser is often scarce. The MSICS should be promoted to allow its widely use in developing countries because of the lack of human resources, infrastructure, and technology in order to accelerate the ight against blindness from cataract.