PURPOSE: We determined if the Impact of Vision Impairment (IVI) is a valid questionnaire to measure the vision-related quality of life (VRQoL) in keratoconus patients, and investigated if the VRQoL varied with disease severity in this sample. METHODS: WE RECRUITED 160 CONSECUTIVE BILATERAL KERATOCONUS PATIENTS (MEAN AGE 23.3 YEARS, 63% MALE) FROM AN INDIAN TERTIARY EYE CARE CENTER. PARTICIPANTS UNDERWENT A CLINICAL EXAMINATION AND COMPLETED THE IVI. PARTICIPANTS WERE DIVIDED INTO THREE GROUPS BASED ON THE AVERAGE OF THE STEEP KERATOMETRY (K) READINGS: mild (average Sim K < 45 diopters [D]), moderate (average Sim K 45-52 D), and severe (average Sim K > 52 D). Rasch analysis was used to validate the IVI and the VRQoL scores thus obtained were compared across the disease groups. RESULTS: THE MAJORITY (63%) OF PATIENTS HAD SEVERE, WHILE THE REMAINDER (37%) HAD MODERATE KERATOCONUS. RASCH ANALYSIS DEMONSTRATED THE VALIDITY OF THE IVI TO ASSESS VRQOL THROUGH TWO SUBSCALES: vision-specific functioning (VF) and emotional well-being (EWB). There was no significant difference in VF (mean change -0.16, P = 0.55) and EWB scores (mean change -0.32, P = 0.23) between moderate and severe keratoconus groups. CONCLUSIONS: The revised IVI subscales have interval-level measurement properties, which support their suitability to measure VRQoL in this keratoconus sample. Patients with moderate or severe keratoconus had similar, but higher VRQoL scores as assessed by the revised IVI subscales, indicating lack of impact of the disease on their VRQoL. However, this does not exclude the possibility of finding an impact in other populations.
PURPOSE: We determined if the Impact of Vision Impairment (IVI) is a valid questionnaire to measure the vision-related quality of life (VRQoL) in keratoconus patients, and investigated if the VRQoL varied with disease severity in this sample. METHODS: WE RECRUITED 160 CONSECUTIVE BILATERAL KERATOCONUS PATIENTS (MEAN AGE 23.3 YEARS, 63% MALE) FROM AN INDIAN TERTIARY EYE CARE CENTER. PARTICIPANTS UNDERWENT A CLINICAL EXAMINATION AND COMPLETED THE IVI. PARTICIPANTS WERE DIVIDED INTO THREE GROUPS BASED ON THE AVERAGE OF THE STEEP KERATOMETRY (K) READINGS: mild (average Sim K < 45 diopters [D]), moderate (average Sim K 45-52 D), and severe (average Sim K > 52 D). Rasch analysis was used to validate the IVI and the VRQoL scores thus obtained were compared across the disease groups. RESULTS: THE MAJORITY (63%) OF PATIENTS HAD SEVERE, WHILE THE REMAINDER (37%) HAD MODERATE KERATOCONUS. RASCH ANALYSIS DEMONSTRATED THE VALIDITY OF THE IVI TO ASSESS VRQOL THROUGH TWO SUBSCALES: vision-specific functioning (VF) and emotional well-being (EWB). There was no significant difference in VF (mean change -0.16, P = 0.55) and EWB scores (mean change -0.32, P = 0.23) between moderate and severe keratoconus groups. CONCLUSIONS: The revised IVI subscales have interval-level measurement properties, which support their suitability to measure VRQoL in this keratoconus sample. Patients with moderate or severe keratoconus had similar, but higher VRQoL scores as assessed by the revised IVI subscales, indicating lack of impact of the disease on their VRQoL. However, this does not exclude the possibility of finding an impact in other populations.
Authors: Eva K Fenwick; Peng Guan Ong; Charumathi Sabanayagam; Gwyn Rees; Jing Xie; Edith Holloway; Ching-Yu Cheng; Tien Y Wong; Blanche Lim; Pok Chien Tan; Ecosse L Lamoureux Journal: Qual Life Res Date: 2015-09-29 Impact factor: 4.147
Authors: Eva K Fenwick; Ryan E K Man; Gwyn Rees; Jill Keeffe; Tien Y Wong; Ecosse L Lamoureux Journal: Qual Life Res Date: 2016-08-24 Impact factor: 4.147
Authors: Sara Ortiz-Toquero; Sofia Perez; Guadalupe Rodriguez; Victoria de Juan; Agustin Mayo-Iscar; Raul Martin Journal: Qual Life Res Date: 2015-09-03 Impact factor: 4.147