Purpose: To determine the minimal clinically important difference and the patient acceptable symptom state for visual acuity and visual function, 2 key visual outcomes for patients undergoing cataract extraction, as an aid for evaluating the outcome of cataract extraction.
Design: Prospective cohort study.
Setting: Multicenter study of 17 hospitals.
Patients: A total of 4335 consecutive patients advised to undergo cataract extraction.
Main outcome measures: Sociodemographic and clinical data, including visual acuity (VA), patient satisfaction, and responses to the Visual Function Index 14 (VF-14) and transitional questions were collected before and after cataract extraction. The patient acceptable symptom state and minimal clinically important difference were estimated for the entire sample and for subgroups by preintervention status and presence of ocular comorbidities.
Results: Among patients with simple cataract, postintervention patient acceptable symptom state values for VA ranged from 0.67 to 0.80, depending on preintervention VA, while VF-14 scores ranged from 88 to 90. For patients with any additional ocular comorbidity, VA ranged from 0.63 to 0.75, depending on preintervention VA, while VF-14 scores ranged from 86 to 92. For the entire sample, postintervention patient acceptable symptom state values were 0.75 for VA and 86.1 for VF-14 scores. Minimal clinically important difference for patients who reported being a little better ranged from 0.17 to 0.5 in VA and 0.41 to 37.46 in VF-14 scores, depending on preintervention status and presence of ocular comorbidities.
Conclusion: The minimal clinically important difference and patient acceptable symptom state values are complementary parameters that may help in the clinical decision-making process by providing more meaningful estimates of the impact of cataract extraction on 2 important outcomes, visual acuity and visual function.
Copyright © 2011 Elsevier Inc. All rights reserved.