Cataract Surgery Audit at a Private Hospital in Saudi Arabia.

BACKGROUND: To assess the visual outcomes following cataract surgeries at a Private Eye Hospital in Riyadh, Saudi Arabia.
METHODS: This was a cohort study of cataract surgeries performed from January to June 2014. Preoperative data were collected on patient demographics presenting and best corrected distance visual acuity (BCVA) and ocular comorbidity. Data were also collected on the type of surgery, type of intraocular lens (IOLs) implanted, and complications. BCVA and refractive status at 6-8 weeks postoperatively were noted. The predictors of vision ≥ 6/18 were identified.
RESULTS: Four hundred eyes of 400 patients underwent cataract surgery. There were 235 (59%) males. Presenting preoperative vision was < 6/60 in 52 (13%) eyes. There were 395 (99%) eyes that underwent IOL implantation following phacoemulsification and 4 eyes received a sulcus fixated IOL. A single piece aspheric IOL was implanted in 358 (90%) eyes and a toric IOL was implanted in 31 (8%) eyes. Postoperative BCVA was classified as a "good outcome" (≥ 6/18) in 320 (80%) and a "poor outcome" (< 6/60) in 24 (6%) eyes. Young age (adjusted odds ratio (OR) = 0.97, P = 0.01), male (adjusted OR = 2.4, P = 0.002), and ocular co-morbidities (adjusted OR = 0.2, P < 0.001) were predictors of vision ≥ 6/18. Complications included a dropped nucleus and a posterior capsular tear in 2 eyes each. Two hundred and fifty-two (63%) eyes were emmetropic or intentionally myopic for distance. Astigmatism < 2 D was present in 264 (66%) eyes and astigmatism > 2 D was present in 33 (8%) eyes.
CONCLUSION: The recent trend of intentional overcorrection in one eye following modern cataract surgery in order to provide some functional near vision indicates that benchmark for success in getting "good visual outcomes" postoperatively (vision of ≥ 6/18) may need to be revised.

INTRODUCTION

Cataract is the cause of 39% of blindness and 33% of severe visual impairment (SVI) in the world.1 The World Health Organization (WHO) in its “VISION 2020: The Right to Sight” initiative encouraged member countries to increase the volume of cataract surgery and maintain high quality of cataract surgeries.2 Monitoring and improving cataract surgery services has been crucial to improving the quality of cataract surgery.34 Therefore, the Saudi Arabian National Prevention of Blindness Committee also recommended a cataract surgery audit at all Ophthalmic Units of the Kingdom.5

Cataract patients approaching private centers in Saudi Arabia could differ from those undergoing surgery at governmental and nongovernmental institutions. For example, in a private sector, educated patients with higher income levels and greater visual needs undergo surgery at earlier stages of cataract development. The outcomes of modern cataract surgery also may differ and needs to be evaluated. The patients undergoing surgery at a private center expect near normal vision and quick recovery. As these patients have paid the premium cost for the surgery, they expect a high standard of clinical and surgical services and expect excellent visual outcomes. There are a number of publications on the outcomes of cataract surgeries at camps, government hospitals, and nongovernmental organizations related to eye care, especially in developing countries.678 To the best of our knowledge, there is no such publication reported in Saudi Arabia.

We performed a cataract surgery audit at a private Eye Hospital in Riyadh Saudi Arabia, to study the profile of adult cataract patients and outcomes of modern cataract surgery.

METHODS

This cohort study assessed postoperative visual outcomes following cataract surgeries at a Private Eye Hospital in Riyadh, Saudi Arabia. The Institutional Ethical and Research Board of the Specialised Medical Centre (SMC), Riyadh approved this study. Oral consent was obtained from all subjects who participated in this study. The confidentiality of the participants maintained for the study. All patients with senile cataract scheduled for surgery at our institution between the first 6 months of 2014 were included in this study. The patients who declined the participation in the study were excluded.

To determine the sample size for the study, we assumed that 90% of eyes scheduled for cataract surgery had vision better than 6/18 and 75% had vision <6/18–6/60 (moderate visual impairment) prior to surgery. To achieve, 95% of confidence interval (CI) and 80% of power of the cohort study, at least 438 adults were required before and after cataract surgery.

Three cataract surgeons and one epidemiologist were the study investigators. The best corrected distance visual acuity (BCVA), as well as presenting a vision of each eye, was measured using a Phoropter (Nidek Inc., Gamagori, Japan). If vision was <3 m, then count fingers at 2 m distance and then 1 m distance. If vision was <1 m, the eye was tested for light perception vision. All eyes were also tested for projection of light rays from the four directions. The distance vision was further categorized into visual impairment grades based on WHO recommendations.9 The best corrected near visual acuity was measured using the Jaeger system.

For each patient age, sex, and the eye with cataract was recorded. A thorough medical history was performed inquired about the ocular disease and surgery and systemic diseases such as diabetes. The anterior segment was examined with a Slit Lamp Bio-microscope (Topcon Corp., Tokyo, Japan). The intraocular pressure was measured using an applanation tonometer attached to the slit lamp. The posterior segment was examined using a +90 D Volk lens after dilation of the pupil with 1% of tropicamide eye drops. Fundus examination results were used to assess possible comorbidities in the retina, vitreous, or optic disc.

The power of the intraocular lens (IOLs) to be implanted was estimated using IOL Master (Carl Zeiss, Vienna, Austria) and then confirmed by Eyecubed (Ellex, Minneapolis, USA). In patients with bilateral cataracts, the eye with worse vision due to cataract and less severe ocular comorbidity was selected for surgery. The status of the lens in the fellow eye was noted as a clear lens, early cataract, aphakia, or pseudophakia.

Intraoperative data were collected on the type and placement of IOLs implant, intraoperative complications, and management. All eyes underwent surgery using a corneal incision, under topical anesthesia and/or peribulbar anesthesia using phacoemulsification and in-the-bag lens implantation as first preference. In these cases, where the IOL could not be placed in-the-bag, sulcus fixation was performed, or the IOL was placed in the posterior chamber.

Postoperative data were collected on BCVA, refractive and ocular status of the eye at 6–8 weeks. Postoperative ophthalmic examinations were similar preoperative examinations. The outcome of the postoperative distance vision was associated to different risk factors. As per the WHO guidelines the postoperative vision was categorized into “good visual outcome” as ≥6/18, “borderline visual outcome” as 6/60 to 6/18, and “poor visual outcome” as <6/60.9

The potential causes of poor visual outcome following the surgery were grouped into: (1) Ocular comorbidity; (2) faulty IOL measurement; (3) residual astigmatism/refractive error (RE); and (4) surgery related (surgical complications).

To calculate the residual RE, we divided into the value of cylinder by two and added to the spherical value of RE. We further categorized the residual RE into “acceptable for distance vision” (−1.0 to +0.5 D), “intentional overcorrection” (−1.0 D to −3.0 D), “undercorrection” (0.6–2.0 D), and “gross miscalculation” (more than +2.0 D or <−3.0 D).

The data were collected on pretested forms and then transferred to an Excel® spreadsheet (Microsoft Corp., Redmond, WA, USA). Univariate analysis using a parametric method was performed with Statistical Package for Social Studies software (SPSS 22; IBM Corp., Armonk, New York, USA). For qualitative variables, frequencies, and percentage proportions were calculated. For quantitative variables, mean, and standard deviations were calculated. For statistical validation, 95% CI of rates and difference of mean with 95% CI along with two sided “P” values were calculated using the “STAT calculator” function of “Open Epi” software.910

To determine the predictors of vision ≥6/18, 6–8 weeks following cataract surgery, we performed binomial regression analysis. We calculated the adjusted OR, the 95% CI and “P” value.

RESULTS

The study cohort was comprised 400 eyes of 400 patients with cataract. All patients completed 6–8 weeks follow-up. The mean age was 61 ± 11 years. There were 235 (59%) males in the cohort. There were 209 right eyes and 191 left eyes. Presenting preoperative vision of eyes with cataract recorded was 300 (75%) of the eyes with vision <6/18 to 6/60 (moderate visual impairment); 23 (6%) eyes had SVI (<6/60–3/60); and there were 29 (7%) blind eyes (vision <3/60). The remaining 48 eyes had 6/18 or better vision. The status of lens in the fellow eye showed that 38 (10%) eyes had clear lens, 193 (48%) eyes had cataract, 168 (42%) eyes were pseudophakic, and only one eye was aphakic.

Postoperatively, the majority of eyes had IOL implanted in the capsular bag (358; 90%). A Hoya IOL was inserted in 358 (90%) of 10 eyes received a Restor IOL (Alcon Inc., Fort Worth, TX, USA), 20 eyes received an Acrysof IQ toric IOL (Alcon Inc., Fort Worth, TX, USA), and 11 eyes received an Acrysof toric IOL (Alcon Inc., Fort Worth, TX, USA). Intraoperative complications included the posterior capsular tear in 2 eyes) and dropped nucleus two eyes. In one case, the IOL was fixated to the sulcus.

Postoperative BCVA is presented in Table 1. Postoperative BCVA was “Good” (VA ≥6/18) in 80% (95% CI: 76–84) of the operated eyes. Borderline outcome (vision <6/18 to 6/60) was recorded in 56 (14%) of eyes postoperatively. Twenty-four (6%) of eyes had “poor visual outcome” (<6/60) postoperatively out of which five eyes were blind (<3/60). The five eyes classified as blind postoperatively had the following pathologies: Four eyes had ocular comorbidity (1 eye with age-related macular degeneration, 1 eye with glaucoma, 1 eye with corneal opacity, and 1 with an irregular cornea) and 1 eye had induced astigmatism as the principle underlying cause. The predictors of vision ≥6/18 the following surgery were younger age, male gender, and the absence of ocular comorbidity [Table 2].

Table 1

Best corrected distance vision in eyes 6-8 weeks after cataract surgery

Table 2

Predictors of BCVA “good visual outcomes” 6-8 weeks following cataract surgery

The gender variation in visual outcome suggested that good visual outcome (≥6/18) in males was significantly greater than in females (relative risk [RR] =1.3 [1.1–1.7], P = 0.01) [Figure 1].

Figure 1

Best corrected visual outcome 6–8 weeks following cataract surgery based on gender

Of the 141 diabetic patients, 108 had good visual outcomes (≥6/18). Of the 259 patients without diabetes, 212 had good visual outcomes (≥6/18). The negative association of diabetes to the good visual outcome was not statistically significant (RR = 0.8 [95% CI: 0.6–1.1]).

The entire study cohort was grouped in those with and without ocular comorbidities and visual outcome were compared. The comorbidities included diabetic retinopathy (61; 15.3%), glaucoma (37; 9.3%), corneal opacities (9; 2.3%), keratoconus (4; 1%), age-related macular degeneration (4; 1%), and myopic degeneration (95; 1.3%). The absence of ocular comorbidity was significantly associated to “good visual outcome” postoperatively (RR = 2.68 [95% CI: 2.0–3.5]) [Table 3].

Table 3

Visual status of eyes 6-8 weeks following cataract surgery by ocular comorbidity

The median residual RE was −0.25 D with a standard error of the mean of +0.06 D, 6–8 weeks postoperatively. In 250 (63%) eyes, the residual RE was between −0.5 D and +2 D (acceptable or intentional overcorrection). In 139 eye, the residual RE was between −0.5 and −2.0 D. In two eyes (0.5%), the residual RE was >−3 D and another 11 eyes (2.7%) it was >+2 D, classified as “gross miscalculation.” Residual RE based on the type of lens implant is presented in Figure 2.

Figure 2

Residual refractive error at 6–8 weeks following cataract surgery based on type of intraocular lens implant

DISCUSSION

In this study, we found that cataract surgery with phacoemulsification and IOL implantation at a private eye institute resulted in an 80% of success rate for achieving “good visual outcomes.” High quality of the cataract surgery using phacoemulsification and IOL implantation in the capsular bag with minimum intraoperative complications was the hallmark of these surgeries. The predictors of “good visual outcomes” were younger age, male gender, and the absence of ocular comorbidity.

The cataract surgeon's efforts in our study achieved less than the global benchmark. The global benchmark is BCVA of 6/18 or better in 85% of eyes postoperatively, set by the WHO and the International Agency for the Prevention of Blindness.211 This global indicator was suggested based on a monofocal IOL implant that targets absolute emmetropia. Currently, cataract patients often undergo monovision correction with IOL lens implantation in one eye targeted for distance and IOL implantation in the fellow eye targeted for near to reduce spectacle dependence postoperatively.12 Hence, monovision and other strategies for providing distance and near vision after cataract surgery indicate that the benchmark of postoperative emmetropia may need revision, especially at cut-off levels for presenting vision. In addition, the benchmarks for binocular vision in bilateral cataract surgery may need revision. This observation likely explains the BCVA and presenting vision differ in the current study. A Cochrane review of a number of cataract audits used “good” visual outcome (vision 6/18 and better) to compare outcomes of phacoemulsification and small incision cataract surgery. The review reported that if presenting (uncorrected) VA instead of BCVA is used for analysis, success rates change.8

The success rate in attaining an outcome of “good” vision in our study is likely higher than 80% as 90% of the cases received monofocal IOLs. In 42% of these cases, the fellow eye already had a monocular IOL implanted, and the ophthalmologist planned to implant monocular IOL in the second eye with the aim to overcorrect and for good unaided near vision. A review of a large dataset in Europe, suggested that outcome of modern cataract surgery could achieve 94% of success rate in obtaining 20/40 or better vision.13 Another factor that may have affected our success rate to achieve good outcomes may be that 32% of operated eyes with ocular comorbidities in Saudi patients of our study as compared to the European study.

A study with a large sample size from 38 developing countries from camp-based cataract surgeries reported the good visual outcome in 59% of eyes.14 A survey in Taif, a Western Region of Saudi Arabia reported that among operated cataract cases of adults 50 years and older, the good visual outcome was achieved in 62% of eyes.15 In Oman, good visual outcomes following cataract surgery were achieved in 65% of operated cases at a tertiary hospital.7 In these studies in the same subcontinent, success rates were lower than international benchmark despite cataract surgeries with IOL implantation. However, the method of assessment, type of surgery (extracapsular cataract extraction, small incision surgery, and phacoemulsification), and follow-up time differed in these studies. Therefore, comparison to our study should be judicious.

In cases with multifocal and toric lenses in our study, very few were under corrected. In the 11 (3%) cases of “gross miscalculation,” the underlying causes of the error should be investigated, and corrective measures taken to improve the quality of cataract surgery.

The profile of cataract patients in the private sector is worth noting. Very few of the patients had advanced stage cataract or SVI. These patients have high expectations regarding the quality of vision the following surgery. Hence, quality control through audits and proper counseling would be crucial for patients undergoing surgery at a private center.

Although unoperated cataract is identified as a leading cause of visual impairment among females in Northern Saudi Arabia, the low cataract surgery rate in a female in our study is worth noting.16 This observation could be due to greater barriers to cataract surgery for females has been reported in Kenya, Bangladesh, and Philippines.17 More male clients for cataract surgeries in our study could also be due to higher priority to males and to undergo surgeries through payment in the private sector.

Good visual outcome following cataract surgery was not associated to the status of diabetes in our study. Diabetes was found to be a risk factor of poor visual outcomes in other studies but more so in cases with advanced diabetic retinopathy.18 Well-controlled diabetes prior to the surgery and patients with early stage diabetes could explain the lack of association in our cohort. For example, patients presenting to a private hospital are more likely to be the wealthier, more educated, and likely to address health conditions in a timely manner.

Ocular comorbidities were significantly associated to the poor visual outcome in our study. Similar observations were noted both in developing and industrialized countries.8192021

In our study, visual outcomes were assessed 6–8 weeks following surgery. The corneal wound healing takes <6 weeks, and refractive correction is routinely offered to operated patients at this time.22 Hence, changes in refractive correction due to the ongoing healing process are less likely to cause further changes in the success rate after 6–8 weeks postoperatively.

Although we studied the short-term outcomes of cataract surgery, we recommend the long-term follow-up to ensure the stability of correction and no late complications. A study of cataract surgery outcomes in elderly population suggested that within 6 months of surgery, changes in VA are mostly influenced by systemic comorbidities such as diabetes, hypertension, and ocular comorbidities.23

There are some limitations to our study. Although refractive status BCVA was documented at 6–8 weeks following surgery, the vision was not recorded at this follow-up. Thus, the comparison of our results to other studies where postoperative vision was used to define the visual outcomes is not possible.

Newer modalities of testing of visual acuity in timed, real-life scenarios that the patients encounter daily, using an automated instrument has been proposed.24 In addition, the measure quality of vision following modern cataract surgeries is required. These measurements should be applied in the private sector in Saudi Arabia for monitoring cataract surgery outcomes.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.