Long-term outcome after cataract surgery : a longitudinal study

Background Cataract surgery is the most common surgical procedure carried out in the developed world and surgery volumes have increased considerably during the last decades. Various aspects of the surgical procedure, including surgical incision size and intraocular lens materials, have changed substantially, improving the safety and the quality of the outcome. Previous research has primarily focused on the visual function results with a short follow-up time. Long-term population-based studies, exceeding a few years, presenting visual functional results postoperatively, have not been published. Aims To determine the effects of cataract surgery on subjectively experienced visual function and visual acuity in a defined population, and compare the results between sub-groups, on a long-term basis. Methods In this prospective, population-based investigation, all patients with presenile and senile cataract (n=810), operated on during a one-year period (1997-98), at Umeå University Hospital were included. The frequency of cataract surgery at that time, was 5.2 per 1000 population studied. Visual acuity was tested and an eye examination was performed before surgery, 4-8 weeks postoperatively, and five and ten years after surgery. Subjective visual function was assessed using self-administered questionnaires (VF-14) at all occasions. Statistical evaluations comprised analyses of variance, Mann-Whitney U-test, chi-square test, multiple linear regression, a life-table calculation, and Cox’s proportional hazard model. Results Five years after cataract surgery, subjective and objective visual function remained stable in most patients. The most frequent cause of deterioration of visual acuity and decrease in VF-14 scores was agerelated macular degeneration (ARMD). Two thirds of the patients in the cohort were women. They were significantly older than the men and more often operated on both eyes. After adjustment for age and visual acuity, women cataract surgery patients assessed their visual function worse than men both before surgery and 4 months postoperatively. Five years after surgery these differences were no longer significant. At baseline, 13% of the patients were diabetics. At the five-year followup, subjective and objective visual function remained stable in most surviving diabetics, and the longitudinal visual function was not significantly worse compared with the non-diabetics. Ten years after surgery, 28% had received treatment for posterior capsular opacification (PCO). A significantly larger proportion of patients less than 65 years at surgery (37%) compared with those 65 years or older (20%) had been treated. Conclusions Most patients sustain their level of visual acuity and visual function also five and ten years after cataract surgery. Ocular co-morbidity, such as ARMD, is the major cause of longitudinally reduced visual function. Patients suffering from diabetes did not have a significantly worse visual function after five years. A surprisingly large proportion of patients had received treatment for PCO after ten years