Cataract is the most common cause of global blindness and visual impairment.1 More than 50% of the cases of blindness are attributed to cataract, whereas a great percentage of these cases are reversible.2 As recommended by the Vision 2020 Initiative, one strategy to decrease cataract-related blindness is to increase the cataract surgical rate (CSR).3,4 Increasing CSR has decreased cataract-related blindness in different countries, especially developing countries.5–7 The minimum CSR recommended by the World Health Organization is 3000 operations per million population, although many studies have suggested higher rates.8–10 However, the rate cannot be considered alone, and one of the objectives of the VISION 2020 is to improve the quality of cataract surgeries.11 An important quality measure is visual outcome, which is in turn impacted by intraoperative complications.12–15 Cataract surgical complications can increase the hospitalization time and impose excess costs to patients and governments.16 Surgeon experience, choice of surgical method, and the quality of the equipment have all been shown to relate to complications of cataract surgery.17,18 Complication rates vary by type, and posterior capsular rupture (PCR) is reportedly the most prevalent.19–21
The latest Iranian Cataract Surgery Survey in Iran was conducted in 2011, and its details have already been published.22,23 Results indicated that CSR was more than 6500 operations per million population, which is relatively high and acceptable. When compared among provinces, CSR between 2006 and 2010 was highest in Tehran.22 However, despite the high CSR, the prevalence of intraoperative complications of cataract surgery and their pattern during the 5 years are not clear. For this reason, the present study was conducted to determine the prevalence of intraoperative complications of cataract surgery in the Province of Tehran and to investigate relationships with patient, surgical, and surgeon-related factors.
MATERIALS AND METHODS
Data were obtained as part of the 2011 Iranian Cataract Surgical Survey, details of which have already been published.23 The target population was all cataract surgeries performed between 2006 and 2010 at surgical centers throughout the nation. Samples were selected through a two-stage cluster sampling approach. In the first stage, we identified all surgical centers with the assistance of the Ministry of Health, Treatment, and Medical Education. Of the 55 centers that met the inclusion criteria in the Province of Tehran, 23 were randomly selected using Microsoft Excel software and the RANDBETWEEN (bottom, top) command without any replacement.
In the second stage, we determined the sampling time frame for each selected center. Excluding the first two weeks of the year, which coincide with the New Year Holidays, one week per season was randomly selected for each center using the Excel software, that is, a total of 4 weeks per year and 20 weeks in 5 years per center. All cataract surgery charts in these 20 weeks were retrieved for on-site data extraction by trained personnel under supervision of an ophthalmologist. Extracted data included age, sex, surgical method, date of visit and surgery, surgeon’s information, and any complication.
Recorded intraoperative complications included vitreous loss (VL), posterior capsular rupture (PCR), retrobulbar hemorrhage (RH), suprachoroidal effusion/hemorrhage (SCH), intraocular lens (IOL) drop, and nucleus drop. Because most cases of VL are associated with PCR, these were classified as PCR with VL (PCR + VL) and PCR without VL (PCR - VL). Cases with more than one complication were counted only once. A specialist was defined as a person with at least 3 years of surgical experience after graduation or one involved in a fellowship program. Residents were persons still completing their ophthalmology residency program.
The prevalence of the cataract surgery complications is described in percentages, along with 95% confidence intervals (95% CIs). The cluster sampling method was taken into consideration in calculating standard errors. Logistic regression was used to investigate relationships of cataract surgery complications with other variables. Multiple logistic regression was used to control for confounders.
We reviewed a total of 8727 charts of patients who underwent cataract surgery between 2006 and 2010 in the Province of Tehran. The mean age of these patients was 64.3 ± 14.2 years (range, 1 to 100 years), and 52.9% were female. The prevalence of intraoperative complications was 4.15% (95% CI, 0.94 to 7.36). As presented in Table 1, PCR + VL was the most common, and IOL drop was the least common complication during these 5 years. Also, PCR, IOL drop, and nucleus drop were significantly more prevalent in women.
Table 2 presents age-specific rates of intraoperative complications. Highest rates were observed in patients younger than 10 years and older than 70 years. This pattern was almost similar for all complications.
According to our results, the total prevalence of the complications of cataract surgery decreased significantly from 6.95% in 2006 to 3.07% in 2010 (p < 0.001).
Table 3 presents complication rates by surgical method during the 5 years of the study. Lensectomy was associated with the most complications and phacoemulsification had the least.
Complications rates were 3.18% (95% CI, 0.47 to 5.88) in patients who had outpatient surgery and 4.11% (95% CI, 0.39 to 8.61) and 13.99% (95% CI, 11.75 to 16.23) in patients who were hospitalized for one and two nights, respectively. The rate of intraoperative complications was 28.4% (95% CI, 28.3 to 28.6) for resident-performed operations and 3.1% (95% CI, 1.5 to 4.7) for surgeries performed by specialists (p < 0.001).
Associations of complications with different variables were examined through simple and multiple logistic regression models. Results of the multiple model are summarized in Table 4.
Main factors associated with an increased risk of complications were resident-performed operations and nonphacoemulsification methods of surgery. Also, the odds of complications were higher in the youngest (<10 years) and oldest (>70 years) of patients. Table 5 shows the number of complications based on CSR, which decreased from 6406 to 4662 cases between 2006 and 2010.
The present report provides the prevalence and trend of intraoperative complications of cataract surgery in Tehran across 5 years from 2006 to 2010. During the 5-year study period, the overall prevalence of intraoperative complications in Tehran Province was 4.15%, with a descending trend from 7% in 2006 to approximately 3% in 2010. Other studies reporting the prevalence of intraoperative complications of cataract surgery are available across the world.24–26 However, comparisons can be difficult because most studies have reported the prevalence of particular types of complications of cataract surgery rather than aggregated rates.
Greenberg et al.27 reported a prevalence of 3.8% for cataract surgery complications during 2005 to 2007 in the United States. In our study, the overall complication rate was high, but showed a decreasing trend, possibly as a result of adopting the phacoemulsification method (phacoemulsification was used in 97.4% of cataract operations during the 5 years of the study28) and increased surgeon expertise. However, because CSR is increasing, educational strategies should be devised by the government to decrease intraoperative complications.29,30 This is especially highlighted when we look at raw numbers: more than 4000 patients experienced complications in the 5-year period studied. Therefore, from the perspective of public health, it is important to pay attention to these operations and their complications and their burden on the society.26,31 For example, a higher prevalence of complications is associated with more frequent postoperative visits and longer follow-up time, and this imposes additional expenses. In a study by Qatarneh et al.,31 cases with posterior capsule tear had more postcataract surgery visits compared with those free of this complication, and they showed how this complication can cause additional financial costs to the health care system.
As mentioned before, PCR + VL was the most common and IOL drop was the rarest complication. The prevalence of PCR + VL was 2.86% in our study. According to previous studies, the prevalence of PCR + VL varies greatly from 1.92% in the United Kingdom to 7% in Turkey.32 Interestingly, high rates of PCR + VL have been reported from the United Kingdom (4.4%) as well.33
The prevalence of PCR - VL was 0.69% in this study. Previous studies have reported different rates ranging from 0.45 to 7.2%.34,35 The relatively low rate of PCR - VL PCR in this study could be caused by the learning curve of the ophthalmologists because most studies with high PCR - VL rates date back to two decades ago. In other words, phacoemulsification was a new method then, and surgeons were not experienced.
According to results, very young and very old age, nonphacoemulsification surgeries, and resident-performed surgeries were associated with higher intraoperative complication rates. The high prevalence of the complications of cataract surgery in children and the elderly has been addressed by a few studies.36,37 In children, more inflammation and adhesion38 make cataract surgery more difficult with more complications. Reasons in the include zonular weakness, corneal opacity, and pupil constriction.36,39 Therefore, it seems that cataract surgery should be performed with more precision and caution in extreme ends of the age range and, if possible, by more experienced surgeons.
In terms of methods, phacoemulsification decreases the odds of intraoperative complications by approximately 85%.25 This has been already confirmed by other studies as well.40,41 One reason for the decreasing trend of complications in this study could be increased rates of phacoemulsification operations in most centers in Tehran (phacoemulsification was used in 97.4% of cataract operations during the 5 years of the study28). The smaller incision and separating the lens from the capsule with a different method decrease the complications of cataract surgery with this method.
As mentioned before, phacoemulsification complications were high in countries like the United States when it was first introduced. This points to the important role of surgeon experience in decreasing complication rates with phacoemulsification.42 We also observed a significantly higher rate of complications among surgeries performed by residents. In addition, our findings indicated significantly higher rates of VL for resident-performed surgeries.
We also found that operations performed by residents were associated with considerably higher complication rates, including VL, without them being necessarily tougher surgeries.29 Moreover, our findings showed that VL was substantially more common in operations performed by residents. Numerous studies worldwide have investigated the quality and complications of resident-performed operations. Haripriya et al.18 reported that, regardless of the type of surgery, intraoperative complications were considerably less if the operations were performed by staff surgeons. Rates of torn or irregular capsulorhexis were 5 and 9%, respectively, in a series performed by Unal et al.43 Kothari et al.44 reported a high VL rate at an educational hospital. Bhagat et al.29 found that the complications of cataract surgery were not high in operations performed by surgeons in New Jersey Medical School; however, a considerable 7% of the operations performed by residents had intraoperative complications.
As CSR increases in Iran and the population ages, it is important to reduce surgical costs. An important factor in this regard is hospitalization costs. Some studies have shown that costs are reduced with the outpatient approach, cutting the expense of a one-night stay can reduce the costs by approximately 20%.45,46 In this regard, it is very important to consider intraoperative complications as well. According to the results of this study, there was a direct relationship between the percentage of cataract surgery complications and the duration of hospitalization; that is, complications increase hospitalization time. This finding, along with the number of cataract complications, indicates that a great number of hospitalized cases are caused by complications. Therefore, controlling the complications of cataract surgery can increase the cost-effectiveness of the surgery. However, multiple comorbidities and the presence of conditions such as glaucoma can impact hospitalization time and must be noted as a confounding factor.
In conclusion, cataract surgical complication rates in Tehran are relatively high compared with other studies. Considering the increase in the number of and the demand for these surgeries, measures are needed to decrease intraoperative complications by working on related factors such as surgical method and surgeon experience and have more experienced surgeons complete the task in older cases who are at a higher risk of experiencing complications.
Department of Epidemiology
Faculty of Public Health
University of Medical Sciences
Received November 26, 2014; accepted October 6, 2015.
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