The frequency of cataract extraction has increased for several years in Sweden1 as well as in other countries.2,3 Many patients having cataract extraction in Sweden are 85 years or older.1 Thus, 5% of the female population and 4% of the male population in Sweden aged 85 to 89 years had cataract extraction in 1997; the surgery rate (procedures/1000 inhabitants) increased in this age group for both sexes by 33% from 1992 to 1997. This increase in surgery rate was equal to that in younger age groups,1 indicating that physician referral for cataract surgery in the very elderly and in younger patients has increased in a similar manner. There seems no sign of unwillingness to refer the very elderly for cataract surgery, as suggested by Ryynanen and coauthors.4
A significant reason for the increase in frequency of cataract extractions is a change in clinical indications for the surgery.2 At present, the aim of cataract surgery is to avoid visual disabilities in daily life and restore normal visual function in both eyes. A close relationship between visual acuity and ability to perform activities of daily living in cataract patients 80 years or older has been reported.5 The postoperative improvement in ability to perform activities of daily living was related to restored visual acuity.5 In another study, cataract surgery was found effective in improving quality-of life-functions in the elderly.6
One question concerning the very elderly is whether the large increase in their surgery rate has been followed by a postoperative improvement in an equal proportion. This report describes 3 year results in the National Swedish Cataract Register (NCR)7 of an ongoing study of the outcomes of cataract surgery. We focus on patients 85 years or older.
Patients and Methods
Since 1995, the NCR has organized a yearly surgical cataract outcome study.7,8 All affiliated clinics are invited to participate; the study includes all patients having surgery during March of a particular year. Participating clinics are also invited to use the Catquest questionnaire with cataract patients included in the March figures. During March 1995, 1996, and 1997, 35 clinics representing 2983, 1648, and 2853 patients (N = 7484), respectively, participated in the outcome study and used the Catquest questionnaire preoperatively and 6 months postoperatively.
In the NCR database from 1992 to 1997, a total of 236 571 cataract surgeries were registered, with 39 213 patients (16.6%) 85 years or older (unpublished data).
The cataract outcome study has been described in detail.8 In short, preoperative and intraoperative data were reported to the NCR at the time of surgery. At the final postoperative follow-up, visual acuity, refraction, and keratometry were reported to the NCR. Co-existing eye disease (vision-threatening) in the operative eye was reported before and after surgery.
The Catquest is an instrument for patient self-assessment of visual function.9 Patients fill out the questionnaire before surgery and 6 months later, receive another questionnaire by mail. Patients having bilateral surgery were excluded from this outcome study to maintain an equal study period and follow-up period between questionnaires. The evaluation of the Catquest outcome has been described.7 Responses are evaluated using a decision model. Briefly, improvement in perceived disabilities, cataract symptoms, and activity level is called a very good benefit; improvement in perceived disabilities and cataract symptoms is called a good benefit; improvement in perceived disabilities is called a moderate benefit; no change in perceived disabilities is called a questionable benefit; deterioration in perceived disabilities is called no benefit.
All statistical evaluations were done using the Statistical Package for the Social Sciences for MS Windows (release 8.0). The association between 2 independent samples was studied using the chi-square test when there were 2 categorical variables (e.g., sex, first- or second-eye surgery, co-morbidity). The association between 2 independent samples of ratio or interval variables (visual acuity) was evaluated using the t test. The association between different preoperative variables and the outcome (dichotomized) was evaluated using logistic regression analysis.
Six months after surgery, 4819 patients (64.4% of original cohort) completed the Catquest questionnaire. The reasons for loss of cases are shown in Table 1. Of the final patient population, 757 (15.7%) were 85 years or older (≥85 group) and 4062 patients were younger than 85 years (≤84 group). Of originally enrolled patients, follow-up was completed by 54.5% in the ≥85 group and 74.0% in the ≤84 group. Thus, among lost cases, the ≥85 group was overrepresented; i.e., 34% of the patients deceased during follow-up were in this group. Furthermore, in this group, 27.0% did not cooperate at follow-up and 21.0% were still under treatment 6 months after surgery.
Women represented 73.4% in the ≥85 group and 66.4% in the ≤84 group. Second-eye surgery was performed in 33.7% and 34.4%, respectively. Patient characteristics are shown in Table 2.
Preoperative visual acuities in the operative eyes are shown in Figure 1, and the best visual acuities in the better eyes preoperatively are shown in Figure 2. Visual acuity was better in the operative eye after surgery in 84.3% in the ≥85 group and 93.4% in the ≤84 group. Visual acuities in the operative eye (0.5 achieved in 71.4% and in 88.7%, respectively; 86.0% of entire study group) are shown in Figure 3.
The phacoemulsification technique was used in 69.7% of the cases in the ≥85 group and 78.0% in the ≤84 group. Table 3 shows surgical technique details.
The need for help in daily living, characterized by having home help, subsidized travel by taxi before and after surgery, or both, is shown in Table 4. In the ≥85 group, 44.7% had home help both before and after surgery. Another 11.0% could quit home help after surgery, and 9.2% had to begin home help during the follow-up. This represents a 1.8% total reduction in patients requiring home help after surgery in this age group. In the ≤84 group, the decrease was 1.6%.
A no-benefit outcome as defined by the Catquest questionnaire was reported by 437 patients (9.1%): 12.4% in the ≥85 group and 8.4% in the ≤84 group. These patients perceived more difficulties in performing everyday activities because of their vision 6 months after surgery than they did before surgery.
The outcome in the 5 benefit levels as defined by the Catquest questionnaire for the 2 groups of patients is shown in Table 5. An improvement in perceived difficulties in daily life was found in 84.8% in the ≤84 group and 77.8% in the ≥85 group.
The outcomes in benefit versus no-benefit depending on preoperative variables are shown in Table 6. There was a significantly worse outcome in the ≥85 group if an ocular co-morbidity was present but no significant difference if no ocular co-morbidity existed. Table 7 shows the no-benefit outcome in the ≥85 group combining the ocular co-morbidity and second-eye surgery variables.
The relationships between different preoperative and postoperative variables and the outcome by benefit or no-benefit showed that ocular co-morbidity was the most important preoperative variable related to outcome in the ≥85 group (Table 8). If both preoperative and postoperative variables are analyzed for a relationship to the benefit outcome, postoperative visual acuity in the operative eye and preoperative disability score sum were most strongly related to the outcomes in both patient groups. If only preoperative variables are included in the analysis, the preoperative disability score sum, ocular co-morbidity, best visual acuity in the better eye, and second-eye surgery were related to the outcome in the ≤84 group. Preoperative disability score sum, ocular co-morbidity, and possibly sex were related to the outcome in the ≥85 group. If the disability score sum as defined by the Catquest questionnaire was not known, second-eye surgery and ocular co-morbidity were related to the outcome in the ≤84 group and only ocular co-morbidity in the ≥85 group.
Patients in the ≥85 group with an ocular co-morbidity and a low preoperative disability score sum (a score sum below 8 on the Catquest; patient perceives no difficulties in performing most everyday activities in questionnaire) had a no-benefit outcome in 29.8% of cases and a questionable benefit outcome in 14.9%. This indicates that about 55.0% of patients reported an improvement in perceived difficulties in performing everyday activities. In contrast, in the ≥85 group, patients with no ocular co-morbidity and high disability score sum (Catquest score greater than 21; patient had great/extreme difficulty performing most everyday activities listed) improved in 96.3% of the cases. Table 9 shows the no-benefit outcome in patients in the ≥85 group by ocular co-morbidity versus disability score sum.
Preoperative visual acuity in the eye to have surgery and best corrected visual acuity in the better eye were significantly worse in the ≥85 group than in the ≤84 group. This probably reflects that the ≥85 group in this study had a higher frequency of ocular co-morbidity and other general disease before surgery than the ≤84 group. This phenomenon, part of the natural aging process, negatively influences the visual outcome of surgery in older patients.10,11 Women were overrepresented in the ≥85 group because they have a longer average life span than men.
The recorded intraoperative variables show that the frequency of phacoemulsification procedures and a posterior chamber intraocular lens was lower in the ≥85 group. However, the results are better for each subsequent study year in both groups, and the difference between groups seems smaller. This probably reflects that (1) surgeon preference for phacoemulsification increased during the study period; (2) phacoemulsification may be more difficult to perform in older eyes, at least at the beginning of the surgeon's learning curve, because these eyes have a higher frequency of hard nuclei, small pupils, and exfoliation syndrome and, in general, patient cooperation is not as good.
We found that second-eye surgery was almost as frequent in the ≥85 group as in the ≤84 group. This indicates that age itself did not preclude second-eye surgery.
In the total study group, visual acuity was 0.5 or better in the operative eye in 86.0% of cases. This is the same as reported in other studies.12,13 In the ≥85 group, 71.4% achieved a postoperative visual acuity of 0.5 or better. The lower percentage probably reflects the higher frequency of ocular co-morbidity in this age group. However, if visual outcome in patients with no ocular co-morbidity is evaluated, the ≥85 group still had a significantly worse outcome (medians: ≤84 group = 0.9, ≥85 group = 0.7; P < .001, t test). Thus, age may have a negative influence on visual outcome.
Cataract extraction may influence the need for help in daily living.5 In this study, many patients in both age groups reported they needed less home help 6 months after surgery than before. A smaller proportion in the ≥85 group with preoperative home help reported no home help after surgery than in the ≤84 group. This is in accordance with the higher frequency of other disease and a poorer visual outcome in the ≥85 group. Many patients in both age groups reported help after surgery but no help before, which might be for reasons other than visual disabilities.
The influence of cataract surgery on requiring subsidized travel by taxi was small in our study, especially in the ≤84 group. In Sweden, persons unable to use public services because of disease or handicap receive subsidized travel by taxi. The majority of patients with preoperative need for help as defined by home help or subsidized travel by taxi continued to require such help after surgery.
In the ≥85 group, 77.7% perceived improvement in difficulties performing daily life activities; this result is good. In 12.7% of cases, patients experienced more difficulties (no benefit) after surgery than before. On average, second-eye surgery did not result in more improvement than first-eye surgery in the ≥85 group (no benefit in 13.7% and 12.2%, respectively). In the ≤84 group, however, second-eye surgery gave a significantly better outcome than first-eye surgery (no benefit in 6.5% and 9.4%, respectively; P = .002, chi-square). This difference in outcome within groups may signify a difference in the ability to return to age-matched normal visual function after second-eye surgery, as described by Elliott and coauthors.14
No between-group difference in benefit outcome was found if no co-existing eye disease was present. In contrast, in patients with ocular co-morbidity, those in the ≤84 group had a significantly better outcome (10.6% no benefit versus 17.3%, respectively; P < .001, chi-square).
The outcome in 5 levels of benefit as defined by the Catquest questionnaire was better in the ≤84 group, especially in terms of achieving the highest level benefit (very good). A very good benefit means an improvement or status quo in the activity level in addition to other improvements.9 As both car driving and employment are included in this evaluation, those in the ≥85 group did not have as many opportunities as younger patients to achieve the highest level of benefit.
In this study, the outcome of cataract surgery in the very elderly should be considered very good. Our findings indicate that certain subgroups of elderly patients may have an excellent outcome. In the ≥85 group, 94.2% with no ocular co-morbidity and scheduled for first-eye surgery had a beneficial outcome, and 94.7% of those with a high disability score sum before surgery had as good a result. There were, however, subgroups in the ≥85 group in which the outcome was not as good. Of those with ocular co-morbidity and scheduled for second-eye surgery, 18.8% had a no-benefit outcome; 29.8% with an ocular co-morbidity and almost no perceived difficulties preoperatively (disability score sum 8 or less) had a no-benefit outcome.
The questions and response options on the Catquest questionnaire determine both the disability score sum and the evaluation of the outcome. Perhaps, as described by Mangione et al.,15 patients improve after surgery in areas not covered by the questionnaire.
A weakness in this ongoing study is the loss of patients during follow-up. The very elderly were overrepresented among the lost cases. Our conclusions are therefore valid for only some originally enrolled patients. It might be that the outcome on average for cases excluded because of missing data was worse than for those reported here. Loss of patients because of death or inability to cooperate is not possible to influence. At the beginning of the study (1995), few patients were excluded for surgery in both eyes during the 6 month follow-up. This number increased, however, for each study year. When a mailed questionnaire is used instead of personal interviews for patient self-assessment of visual function, more are lost to follow-up.7
A strength of this study is that it reflects the results in daily practice at a large number of clinics on a national level. It works as a window through which results of common daily practice can be studied.
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