Patients' perception of visual impairment in glaucoma: a pilot study

Abstract

Background/aims-There is a paucity of useful information on the level of visual disability suVered by glaucoma patients. The aims of this study were to determine and rank the frequency of self reported visual disability in daily tasks performed by glaucoma patients; to examine the interrelation between disabilities using factor analysis; to study the relation between perceived visual diYculty and a measure of the severity of visual field loss; to develop a glaucoma specific subgroup of questions; and examine the validity and reliability of this subgroup of questions. Methods-63 glaucoma patients completed a questionnaire containing 62 questions covering 10 broad aspects of daily life activities using a five point answer scale. Patients were classified into three groups as having mild, moderate, and severe field loss on the basis of the perimetric results. The relation between a measure of the severity of visual field loss and subjective visual disability in the three groups was examined. Results-Using factor analysis, the most frequently reported problems were grouped into the following four categories: outdoor mobility, glare and lighting conditions and activities demanding functional peripheral vision, household tasks, and personal care. These four factors accounted for 72% of the variability in the patients' questionnaire responses. With increasing severity of binocular visual field loss there was an increase in the number of self reported visual problems. A loss of confidence in performing some routine daily tasks tended to precede self reported specific visual disabilities. The factor "glare and lighting and activities demanding functional peripheral vision" was found to have a significant relation with a measure of visual field loss and was used to create a glaucoma specific subset of questions. Cronbach's showed a high degree of reliability and internal consistency ( =0.96) in this glaucoma specific subset of questions. Furthermore, the validity of this new subset of questions was shown to be significant (r=0.037, p<0.05) for the correlation between a measure of the severity of binocular visual field loss and the mean score of the variables used in the glaucoma specific subgroup of questions. Conclusions-Outcome measures and quality of life issues need to be addressed in glaucoma. This pilot study identified common problems encountered by patients which at the present time are not assessed in routine glaucoma care. It also identified a subgroup of questions that seems to be specific for glaucoma. Further research is required if a significant impact on the quality of life of glaucoma patients is to be achieved. (Br J Ophthalmol 1999;83:546-552)

Patient-reported outcomes (PRO's) in glaucoma: a systematic review

“…QoL is a multi-dimensional concept, yet the GQL-15 only contains items representing visual activities, which is only one dimension of QoL. 27,28 The same is true for the GSI, pretending to measure the impact of glaucoma symptoms on QoL, yet mostly containing items related to visual activities as well. 26 …”

“…Overall, the tools for assessing functional status demonstrated poor quality both in view of their development as well as for their validation process. Yet, further adaptation and testing could improve instruments with potential, such as the GQL-15, IMQ and the GSI [24][25][26][27][28] Within the QoL-measures, both the Glau-QoL and VisQoL had an extensive and theory based development process, but were generated and validated according to classical techniques. [43][44][45] Applying additional Rasch-analysis could strengthen their content and validity.…”

Severity of Visual Field Loss and Health-related Quality of Life

“…1 Visual impairment is assessed by several measures including visual acuity (VA) and peripheral visual field. Worse VA has been associated with a decreased ability to complete daily activities 2,3 , increased falls 4 , increased risk of car accidents 4 , and increased mortality. 5 Less is known about the impact of peripheral visual field loss (VFL) on the ability of people to perform normal, daily activities, however there is evidence that VFL, independent of VA, is associated with diminished mobility, diminished ability to complete activities such as reading or watching television 6 , and with an increased risk of falling and/or injury.…”

Central field perimetry of discriminated targets: I. Results for normal individuals using high-contrast targets

“…[15][16][17] However, contrast perimetry, when used to measure vision loss in the central field (for example, central test pattern 10-2), similar to acuity, correlates poorly with visual performance in ADL. 18 Microperimetry testing integrates fundus imaging with contrast perimetry to allow the testing locations to be compared with fundus pathology, [19][20][21][22] but similar to Humphrey contrast perimetry, microperimetry measures only the detection of targets contrasted against a uniformly luminant background. Discriminated targets are not evaluated, and testing cannot be performed with a variance of background luminance or hue.…”