Cataract surgery is the most common eye surgery performed worldwide. Cataract surgery rates are estimated to be about 3500 to 5000 per million of the general population in developed countries.1 With advances in technology, a large proportion of cataract surgeries are currently carried out using phacoemulsification performed under topical anesthesia.
The subjective visual experience of patients during cataract surgery has been reported in several studies.2–10 In general, these papers report similar visual experiences during cataract surgery: no perception of light, light perception, perception of 1 or more colors, flashes of light, movements, instruments, and surgeon's hands or fingers. Of clinical significance is that some patients have found these visual sensations frightening.5,6,8–11 To our knowledge, no data have been published regarding the effect of preoperative counseling about the intraoperative visual experience on allaying fear in these patients.
We conducted a multicenter randomized clinical trial to evaluate the effectiveness of administering additional preoperative counseling on reducing fear in patients having phacoemulsification under topical anesthesia.
PATIENTS AND METHODS
Tan Tock Seng Hospital is a tertiary government hospital with 1200 beds. The Eye Institute at Tan Tock Seng Hospital has an annual outpatient attendance of 76 000 patients and performs an average of 4500 cataract surgeries per year. The Hull Royal Infirmary is part of the Royal Hull Hospitals National Health Service (NHS) Trust and is affiliated with the Hull and York Medical School. It has 721 beds. The Department of Ophthalmology carries out about 4000 cataract surgeries per year. The Manchester Royal Eye Hospital (MREH) operates as the Ophthalmic Directorate within the Central Manchester and Manchester Children's University Hospitals NHS Trust. It has 26 NHS beds and 7 private beds. The hospital performs about 4500 cataract operations per year. The hospital sees 22000 new cases and 58 000 follow-up cases yearly.
This study was approved by the ethics committee for research projects in Tan Tock Seng Hospital, but further ethics committee approval was deemed unnecessary in the other centers.
All patients were randomized to 2 groups—additional counseling (Group A) and no additional counseling (Group B)—using a table of random numbers. Both groups had routine preoperative counseling regarding risks and benefits of cataract surgery. Group A patients received additional counseling on the potential intraoperative visual experience during phacoemulsification under topical anesthesia. This additional counseling was standardized across all 3 centers.
Group A patients were specifically told that they might experience any of the following visual sensations; namely, no perception of light, light perception, perception of 1 or more colors, flashes of light, movements, images of instruments, and images of surgeon's hands or fingers. They were advised not to be alarmed or frightened. Group B patients did not receive this additional counseling. In each of the 3 centers, both routine and additional preoperative counseling was carried out by the surgeon.
Patients with complicated cataract surgery (ie, ruptured posterior capsule, anterior vitrectomy) and patients who could not complete the interview (ie, those with dementia, hearing impairment) were excluded.
All patients received preoperative medications that included dilating drops (cyclopentolate 1% or tropicamide 1% with/without phenylephrine 2.5%), topical nonsteroidal antiinflammatory drugs (flurbiprofen sodium 0.03% or diclofenac sodium 0.1%), and topical anesthetics (proxymetacaine 0.5% or amethocaine 1%).
Three surgeons (K.-G.A.E., D.V.) performed the cataract surgery, 1 from each of the 3 study centers. Intraoperatively, cataract surgery was carried out using the Carl Zeiss OPMI 6 microscope under coaxial lighting. Phacoemulsification technique was standardized for each surgeon; either stop and chop or divide and conquer, followed by implantation of a foldable intraocular lens (IOL).
Main Outcome Measures
Patients were interviewed using a standardized postoperative questionnaire within 24 hours of surgery regarding their visual experience in the operated eye and whether they felt frightened by the visual sensations. The interviewer was an ophthalmologist who was masked regarding the counseling status of the patients. Each interview lasted between 3 and 5 minutes and was conducted in the patient's spoken language. In Singapore, the interview was conducted predominantly in Mandarin, as well as in English, Malay, and local dialects such as Hokkien and Cantonese. In the UK, the interview was carried out in English. The same interviewer was used each time to ensure consistency.
A visual analog fear scale was devised to assess the presence or absence of fear in these patients. The visual analog fear scale consists of integers ranging from 0 to 10. Zero denotes the absence of fear, while the sensation of fear is graded in increasing severity from a score >0 to a maximum of 10 (worst fear you have experienced). Patients were shown the fear analog scale and asked to quantify their fear, if present. Patients who were not counseled were asked whether they thought that additional counseling would be useful. Patients who were counseled were asked whether the additional counseling they received was useful.
Sample size calculations were performed to estimate the number of patients in each group. Assuming the differences in the proportion frightened were 15% in the uncounseled group and 3% in the counseled group, the sample size calculated for power of 80% and alpha of 0.05 were 105 patients in each group.
Proportions were compared using the χ2 test, and the fear scores were compared using the nonparametric Wilcoxon rank sum test. Logistic regression analysis was conducted with counseling as the dependent variable and fear score and coexisting ocular pathology as covariates.
Two hundred nineteen patients were recruited over an 11-month period. There were 104 men and 115 women. The mean age was 68 years (range 20 to 89 years). There were 188 Singaporeans, comprising 168 Chinese, 13 Malays, and 7 Indians, and 31 British patients, all of whom were white.
There was no significant difference between those who were counseled and those who were not in study center, age, sex, laterality, history of cataract surgery in the fellow eye, bestcorrected visual acuity (BCVA), and duration of surgery (Table 1). The only significant difference was the presence of coexistent ocular pathology, which was more frequently present in those who were counseled (43.3%) than in those who were not counseled (30.4%) (P = .049).
Table 2 shows the effect of counseling on fear. More patients who were not counseled were frightened (19.1%) than those who were counseled (13.5%) in the entire study group, although this did not reach statistical significance. However, those who were not counseled were more frightened than those who were counseled in terms of the mean fear score. The mean fear score was higher in those not counseled (0.9) than in those counseled (0.3; P = .036).
Counseling appeared to reduce the mean fear score to a greater extent among the Singaporeans. The mean fear score was 1.1 (SD 2.3) in Singaporeans who were not counseled compared with 0.4 (SD 1.0) in Singaporeans who were counseled (P = .033). There was no significant difference in the mean fear score between British patients who were not counseled (mean fear score 0.06, [SD 0.2]) and those who were counseled (mean fear score 0.0, [SD 0.0]) (P = .40).
Female patients who were counseled had a significant reduction in mean fear score (0.4 [SD 1.1]) compared with those who did not receive additional counseling (1.4 [SD 2.7]) (P = .021). There was no statistical difference demonstrated in the male patients (0.2 versus 0.5, P = .44). The effect of counseling on fear was significant (P = .002) even after controlling for sex, age, and whether it was the patient's first or second cataract surgery.
We also found that most patients generally found additional preoperative counseling useful. This was particularly appreciated in the group that had received the additional counseling before their surgery (90.4%) compared with those who had not received additional counseling (76.5%; P = .006)
The magnitude of the fear score (0 to 10) experienced by all the patients was analyzed and compared using the nonparametric Mann-Whitney test between the groups to try to identify any association. It was found that the center where the surgery was performed (Singapore versus United Kingdom; P = .036), timing of surgery (first cataract surgery versus second; P = .003), age of patient (less than 60 years old versus more than 60 years old; P = .03), and sex (men versus women; P = .089) were significant factors. Using multiple linear regression analysis with the fear score as the dependent variable, patients who were younger (less than 60 years old; P = .001) and female (P = .017) were more likely to report higher levels of fear during cataract surgery.
Our randomized clinical trial showed that preoperative counseling about potential intraoperative visual experience during phacoemulsification under topical anesthesia helps to reduce the fear from the visual sensations in patients having cataract surgery. This was particularly evident among Singaporeans and women. Factors associated with a greater likelihood of experiencing fear were younger age, being female, and having cataract surgery for the first time. Most patients found additional preoperative counseling useful to them.
Several studies have been conducted regarding visual experience during cataract surgery under retrobulbar,2–5 topical,6,7 and sub-Tenon's anesthesia.8 It has been postulated that these visual images arise as a result of a combination of images outside the eye, entoptic phenomena, and dynamic factors within the eye.3,12–14 Patients who have received regional anesthesia still perceive these images due to the incomplete effect of the regional anesthesia on the function of the optic nerve. Tranos et al.14 compared visual perception during phacoemulsification under topical versus regional anesthesia in a nonrandomized study and showed that the patients who were operated on under topical anesthesia were more aware of the various visual sensations compared with those who were operated on under regional anesthesia.
The patient information leaflet in the Cataract Surgery Guidelines15 states that patients will be aware of bright light during cataract surgery only under local anesthesia. It has been recommended that these recent findings on intraoperative visual sensations be incorporated into these guidelines.16,17
Some of the studies suggest that fear during cataract surgery is a significant problem.5,6,8–11 Some patients operated on under topical anesthesia have even indicated their preference for retrobulbar anesthesia, despite its risks, to reduce their ability to see during surgery.6
This study may have implications for other ophthalmic surgical procedures. Fear may be allayed by routinely administering additional preoperative counseling on the possible intraoperative visual experience for a variety of ophthalmic surgical procedures. The benefits are 2-fold: first, improving patient satisfaction; second, helping to reduce fear-related medical conditions (ie, uncontrolled hypertension).
In conclusion, we suggest that information on possible intraoperative visual experiences should be included as part of routine preoperative counseling in patients having cataract surgery to allay their fear from these visual sensations during surgery.
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