RESUMEN

BACKGROUND: Parents of a child with disability must cope with greater demands than those living with a healthy child. Coping refers to a person's cognitive or behavioral efforts to manage the demands of a stressful situation. The Coping Health Inventory for Parents (CHIP) is a well-recognized measure of coping among parents of chronically ill children and assesses different coping patterns using its three subscales. The purpose of this study was to provide further insights into the psychometric properties of the CHIP subscales in a sample of parents of children with disabilities. METHODS: In this cross-sectional study, 220 parents (mean age, 33.4 years; 85% mothers) caring for a child with disability enrolled in special schools as well as in mainstream schools completed the 45-item CHIP. Rasch analysis was applied to the CHIP data and the psychometric performance of each of the three subscales was tested. Subscale revision was performed in the context of Rasch analysis statistics. RESULTS: Response categories were not used as intended, necessitating combining categories, thereby reducing the number from 4 to 3. The subscale - 'maintaining social support' satisfied all the Rasch model expectations. Four item misfit the Rasch model in the subscale -maintaining family integration', but their deletion resulted in a 15-item scale with items that fit the Rasch model well. The remaining subscale - 'understanding the healthcare situation' lacked adequate measurement precision (<2.0 logits). CONCLUSIONS: The current Rasch analyses add to the evidence of measurement properties of the CHIP and show that the two of its subscales (one original and the other revised) have good psychometric properties and work well to measure coping patterns in parents of children with disabilities. However the third subscale is limited by its inadequate measurement precision and requires more items.

Asunto(s)

RESUMEN

BACKGROUND: Depression and anxiety are two common normal responses to a chronic disease such as glaucoma. This study analysed the measurement properties of the depression screening instrument - Patient Health Questionnaire-9 (PHQ-9) using Rasch analysis to determine if it can be used as a measure. METHODS: In this hospital-based cross-sectional study, the PHQ-9 was administered to primary glaucoma adults attending a glaucoma clinic of a tertiary eye care centre, South India. All patients underwent a comprehensive clinical evaluation. Patient demographics and sub-type of glaucoma were abstracted from the medical record. Rasch analysis was used to investigate the following properties of the PHQ-9: behaviour of the response categories, measurement precision (assessed using person separation reliability, PSR; minimum recommended value 0.80), unidimensionality (assessed using item fit [0.7-1.3] and principal components analysis of residuals), and targeting. RESULTS: 198 patients (mean age ± standard deviation  = 59.83±12.34 years; 67% male) were included. The native PHQ-9 did not fit the Rasch model. The response categories showed disordered thresholds which became ordered after category reorganization. Measurement precision was below acceptable limits (0.62) and targeting was sub-optimal (-1.27 logits). Four items misfit that were deleted iteratively following which a set of five items fit the Rasch model. However measurement precision failed to improve and targeting worsened further (-1.62 logits). CONCLUSIONS: The PHQ-9, in its present form, provides suboptimal assessment of depression in patients with glaucoma in India. Therefore, there is a need to develop a new depression instrument for our glaucoma population. A superior strategy would be to use the item bank for depression but this will also need to be validated in glaucoma patients before deciding its utility.

Asunto(s)

RESUMEN

PURPOSE: We evaluated the utility values (UVs), using the time trade off (TTO) technique, associated with primary glaucoma and varying degrees of visual field (VF) loss. METHODS: In this cross-sectional study, 198 adults (mean age, 59.8 years) with primary glaucoma were recruited from the glaucoma clinic of a tertiary center in Hyderabad, South India. Each patient underwent comprehensive glaucoma evaluation, and completed the utility (TTO) and Glaucoma Quality of Life-15 questionnaires (Rasch version, Glaucoma Activity Limitation [GAL]-10). Better mean deviation (MD, using Humphrey Field Analyzer program 24-2) between two eyes was used to classify participants into mild, moderate, and severe VF loss groups. Utilities (range, 0.0-1.0) derived by TTO technique (lifetime traded against perfect vision) and interval level Rasch scores of GAL-10 were used for analyses. RESULTS: Mean UV was 0.81 (95% confidence interval [CI], 0.78-0.84); that is, a decrease in quality of life (QoL) of 19%. Of the subjects, 59% were willing to trade lifetime in return of perfect vision; those willing to trade were significantly younger with poorer acuity in the worse-seeing eye. In univariate and multivariate analysis, severe VF loss in the worse eye was associated with lower UV (ß = -0.108; 95% CI, -0.201 to -0.014; P = 0.02). CONCLUSIONS: Our results show that primary glaucoma in adults causes substantial decrease in UVs (and QoL thereof), and is highly dependent on the severity of VF loss in the worse eye.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the corneal topography, thickness, and elevation (anterior and posterior corneal surface) in children. METHODS: One hundred eyes of 100 patients with a mean ± standard deviation age of 10.6 ± 2.7 years (range: 5 to 15 years) were imaged. The corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, island, and unclassified patterns. RESULTS: Mean simulated keratometry (Sim K) astigmatism was -0.69 ± 0.35 diopters (D) with mean maximum and minimum keratometry (K) of 44.26 ± 1.55 and 43.56 ± 1.57 D, respectively. Mean astigmatism and refractive power in the 3- and 5-mm zones was 0.64 ± 0.36, 43.85 ± 1.53 and 0.78 ± 0.5, 43.41 ± 1.48, respectively. The thinnest site on the cornea had an average thickness of 540 ± 34.03 µm. This site was most commonly located in the inferotemporal quadrant in 61% of eyes, followed by the superotemporal quadrant in 31%. Among the nine regions of the cornea evaluated, the central cornea had the lowest average thickness of 540 ± 34.03 µm and the superonasal cornea had the greatest average thickness of 628 ± 38.94 µm. The most common anterior corneal elevation pattern was the incomplete ridge (52%), followed by the island pattern. The incomplete ridge was most commonly observed on the posterior corneal elevation map (35%). CONCLUSIONS: These results provide normal standards for elevation and curvature topography and corneal thickness in children. These data may prove useful as a reference for future comparative studies of different corneal diseases in children.

Asunto(s)

RESUMEN

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.

Asunto(s)

Asunto(s)

RESUMEN

PURPOSE: The L. V. Prasad-Functional Vision Questionnaire (LVP-FVQ) was developed using Rasch analysis to assess self-reported difficulties in performing daily tasks in school children with visual impairment (VI) in India. However, the LVP-FVQ has psychometric problems of inadequate measurement precision and lack of detailed assessment of dimensionality. Furthermore, items pertaining to use of technology are lacking. The aim of this study was to present the development and validation of the second version of LVP-FVQ (LVP-FVQ II). METHODS: Development of LVP-FVQ II involved extracting items from other similar questionnaires (albeit developed for Western populations) and focus group discussions of children with VI and their parents that resulted in a 32-item pilot questionnaire. Overall, six items from the LVP-FVQ were retained. The questionnaire underwent pilot testing in 25 such children, following which a 27-item LVP-FVQ II emerged, and this was administered to 150 children with VI. Response to each item was rated on a three-category scale. Rasch analysis was used to validate the LVP-FVQ II. RESULTS: Rating scale was used by participants as was intended to. Four mobility-related items required deletion, as these did not contribute toward measurement of a single construct, indicating a secondary dimension. Deletion of the four items resulted in the 23-item unidimensional LVP-FVQ II, with good measurement precision, effective targeting of item difficulty to participant ability, and lack of notable differential item functioning. The LVP-FVQ II has high reliability, indicating that it is effectively able to discriminate between visual disability of school children in India, and is valid across age, gender, duration of VI, and location of residence. CONCLUSIONS: Given the superior measurement properties and the interval-level scores, the LVP-FVQ II appears to offer advantages over LVP-FVQ in assessment of difficulties in performing daily tasks in this population. It can be adapted for use in other developing countries.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the impact of glaucoma on visual functioning in Indians. METHODS: Patients attending the glaucoma service who had undergone a comprehensive glaucoma evaluation were recruited. Better mean deviation (MD, using Humphrey Field Analyzer program 24-2) between two eyes was used to classify participants into mild, moderate, and severe visual field (VF) loss groups. Participants were administered the Glaucoma Quality of Life-15 (GQL-15) questionnaire. Rasch analysis was used to validate the GQL-15 and its four subscales. Linear regression was used to determine associations between GQL-15 scores and VF loss after adjusting for sociodemographic variables. RESULTS: A total of 198 patients (mean age ± SD, 59.8 ± 12.3 years; 67% male) were recruited. Participants with severe VF loss (39%) followed by mild loss (35%) comprised the largest group. Rasch analysis resulted in a 10-item reliable and valid questionnaire: the Glaucoma Activity Limitation-10 (GAL-10). Although a single subscale, "peripheral vision," met requirements of the Rasch model, it could not be preserved in the GAL-10. In multivariate analyses, the middle-income group (compared with higher income) and severe VF-loss (compared with mild VF-loss) participants reported significantly poorer functioning on GAL-10 ([ß = 0.84; 95% confidence interval (CI), 0.16-1.52; P = 0.02] and [ß = 1.19; 95% CI, 0.61-1.78; P < 0.000], respectively). None of these associations were, however, clinically significant. CONCLUSIONS: Glaucoma patients in India, especially those with severe VF loss, face significant challenges in performing daily tasks and in mobility. It is important to prevent progression such that activity limitation is minimized in glaucoma patients.

Asunto(s)

RESUMEN

PURPOSE: Both the long form visual functioning scale (LFVFS(39)) and visual functioning scale (VFS) are measures of visual functioning (VF) that represent the Rasch-scaled versions of the NEI-VFQ(39) and the Indian vision function questionnaire (IND-VFQ), respectively. The objectives of this study were to investigate if the 15-item LFVFS(39) and 13-item VFS of the IND-VFQ meet the assumptions of the Rasch model and measure the same construct, VF, in an Indian visually impaired (VI) population. METHODS: Data from 120 VI adults administered both instruments concurrently, were fitted to the Rasch measurement model to demonstrate that each instrument satisfies the assumptions of the model (including unidimensionality by principal components analysis); and both instruments can be cocalibrated onto a single underlying continuum of VF. RESULTS: Both instruments required category reorganization for optimal rating scale functioning and possessed similar measurement precision (person separation = 2.76). Separate analysis of each instrument (eigenvalues, 2.3 and 1.9 for LFVFS(39) and VFS of IND-VFQ, respectively) and the pooled 28-item analyses (eigenvalue, 2.8) satisfied the assumptions of the Rasch model, including unidimensionality. Furthermore, all items fit in the separate and pooled analyses. Separate item and person measures for each instrument correlated strongly with estimates from the pooled data (r > 0.9 for all, P < 0.0001). CONCLUSIONS; Both the LFVFS(39) and VFS of the IND-VFQ measure the same construct, VF, and with equal measurement precision in an Indian VI population. Both instruments can be calibrated onto a single metric, thereby, enabling a comparison of their measurement range of VF.

Asunto(s)