Christina Zetterlund

Eye-neck interactions triggered by visually deficient computer work

OBJECTIVES To study the joint occurrence of eye-and-neck/scapular area symptoms and their association with occupational risk factors in a cross-sectional sample of professional information technology users. STUDY POPULATION The participants consisted of 3,971 employees who worked with computers for a minimum of one hour a day. 2,551 (73%) were men and 945 (27%) women, with an age range of 18 up to 64 years. The mean age was 38.1 (SD=10.7) for men and 37.6 (SD=12.0) for the women. The measures were obtained via a self-administered survey in combination with a visual examination conducted by an optometrist. METHODS Two complementary logistic regression analyses with forced entry was conducted on n=3,496 (88% adjusted response rate) cases. The effect of ocular symptoms on the risk of reporting musculoskeletal symptoms, or vice versa, was examined first in two separate binominal logistic regression analyses. Age, Gender, Near work variable and Visual functioning variables were included in these analyzes. Variables associated with the risk of developing an increase in either symptom category were also examined in two additional binomial logistic regression analyses. RESULTS Exposure to spectacles (single vision, multifocal, or progressive correction) in combination with a visual acuity <1 surfaced as a key mediator of symptoms from the neck/scapular area (p<0.01). A vergence disparity (uncompensated vergence error) similarly was associated with an augmented risk of developing an increase in neck/scapular area symptoms (p<0.05). The most influential risk factor for neck/scapular area symptoms were ocular symptoms and vice versa (p<0.0001). CONCLUSIONS The results support the hypothesis which postulates that eye-neck/scapular area symptoms interaction may be due to a functional coupling from and between the eye-neck/scapular area muscles [28].

Effects of Feldenkrais Method on Chronic Neck/Scapular Pain in People With Visual Impairment: A Randomized Controlled Trial With One-Year Follow-Up

OBJECTIVE To determine whether the Feldenkrais method is an effective intervention for chronic neck/scapular pain in patients with visual impairment. DESIGN Randomized controlled trial with an untreated control group. SETTING Low vision center. PARTICIPANTS Patients (N=61) with visual impairment (mean, 53.3 y) and nonspecific chronic (mean, 23.8 y) neck/scapular pain. INTERVENTIONS Participants were randomly assigned to the Feldenkrais method group (n=30) or untreated control group (n=31). Patients in the treatment group underwent one 2-hour Feldenkrais method session per week for 12 consecutive weeks. MAIN OUTCOME MEASURES Blind assessment of perceived pain (visual analog scale [VAS]) during physical therapist palpation of the left and right occipital, upper trapezius, and levator scapulae muscle areas; self-assessed degree of pain on the Visual, Musculoskeletal, and Balance Complaints questionnaire; and the Medical Outcomes Study 36-Item Short-Form Health Survey bodily pain scale. RESULTS Patients undergoing Feldenkrais method reported significantly less pain than the controls according to the VAS and Visual, Musculoskeletal, and Balance Complaints questionnaire ratings at posttreatment follow-up and 1-year follow-up. There were no significant differences regarding the Medical Outcomes Study 36-Item Short-Form Health Survey bodily pain scale ratings. CONCLUSIONS Feldenkrais method is an effective intervention for chronic neck/scapular pain in patients with visual impairment.

Reliability and Validity of the Visual, Musculoskeletal, and Balance Complaints Questionnaire

Purpose To evaluate the reliability and validity of the 15-item Visual, Musculoskeletal, and Balance Complaints Questionnaire (VMB) for people with visual impairments, using confirmatory factor analysis (CFA) and with Rasch analysis for use as an outcome measure. Methods Two studies evaluated the VMB. In Study 1, VMB data were collected from 1249 out of 3063 individuals between 18 and 104 years old who were registered at a low vision center. CFA evaluated VMB factor structure and Rasch analysis evaluated VMB scale properties. In Study 2, a subsample of 52 individuals between 27 and 67 years old with visual impairments underwent further measurements. Visual clinical assessments, neck/scapular pain, and balance assessments were collected to evaluate the convergent validity of the VMB (i.e. the domain relationship with other, theoretically predicted measures). Results CFA supported the a priori three-factor structure of the VMB. The factor loadings of the items on their respective domains were all statistically significant. Rasch analysis indicated disordered categories and the original 10-point scale was subsequently replaced with a 5-point scale. Each VMB domain fitted the Rasch model, showing good metric properties, including unidimensionality (explained variances ≥66% and eigenvalues <1.9), person separation (1.86 to 2.29), reliability (0.87 to 0.94), item fit (infit MnSq’s >0.72 and outfit MnSq’s <1.47), targeting (0.30 to 0.50 logits), and insignificant differential item functioning (all DIFs but one <0.50 logits) from gender, age, and visual status. The three VMB domains correlated significantly with relevant visual, musculoskeletal, and balance assessments, demonstrating adequate convergent validity of the VMB. Conclusions The VMB is a simple, inexpensive, and quick yet reliable and valid way to screen and evaluate concurrent visual, musculoskeletal, and balance complaints, with contribution to epidemiological and intervention research and potential clinical implications for the field of health services and low vision rehabilitation.

Visual, musculoskeletal, and balance complaints in AMD: a follow-up study

Purpose. To investigate whether patients with age-related macular degeneration (AMD) run a potentially higher risk of developing visual, musculoskeletal, and balance complaints than age-matched controls with normal vision. Methods. Visual assessments, self-rated visual function, self-rated visual, musculoskeletal, and balance complaints, and perceived general health were obtained in 37 AMD patients and 18 controls, at baseline and after an average of 3.8 years later. Results. At follow-up both groups reported decreased visual acuity (VA) and visual function, but only AMD patients reported significantly increased visual, musculoskeletal, and balance complaints. Decreased VA, need for larger font size when reading, need for larger magnification, and decreased self-rated visual function were identified as risk markers for increased complaints in AMD patients. These complaints were also identified as risk markers for decreased health. For controls, decreased VA and self-reported visual function were associated with increased visual and balance complaints. Conclusions. Visual deterioration was a risk marker for increased visual, musculoskeletal, balance, and health complaints in AMD patients. Specifically, magnifying visual aids, such as CCTV, were a risk marker for increased complaints in AMD patients. This calls for early and coordinated actions to treat and prevent visual, musculoskeletal, balance, and health complaints in AMD patients.

Visual, musculoskeletal and balance symptoms in individuals with visual impairment: Visual and balance symptoms

Visual impairment is globally among the most prevalent disabilities. Research concerning the health consequences of visual deficits is challenged by confounding effects of age, because visual impairment becomes more prevalent with age. This study investigates the influence of visual deficits on visual, musculoskeletal and balance symptoms in adults with and without visual impairment, while controlling for age effects.

Effect of reduced visual acuity on precision of two-dimensional tracing movements

Purpose We intended to assess consequences of reduced visual acuity for performance in a natural simple motor task (tracing) using objective kinematic performance measures. Specifically, we intended to elucidate the kind of relationship between the task performance and best corrected binocular visual acuity and to determine the threshold of visual acuity when task performance starts to deteriorate. Methods Ninety-five individuals with different best corrected visual acuity participated in the study (age 49 ± 12 years, mean ± SD, 27 men and 68 women). The participants manually traced maze-like visual patterns of different spatial complexity presented on the screen of a portable notebook computer using Clinical Kinematic Assessment Tool software. Tracing error was computed as performance measure in each trial with a spatial pattern matching technique – rigid point set registration method. Results The segmented linear regression analysis showed that the relation between visual acuity and tracing errors was best described with a regression function having a break point between two data segments. Tracing performance was unaffected by values of visual acuity below 0.2 on logMAR scale, but when logMAR values increased above this critical limit (i.e. when visual acuity is further reduced), tracing errors linearly increased. The rate of the increase of the tracing error correlated with the complexity of visual stimulus shape. Conclusion Testing of fine motor functions with objective kinematic measures during visuomotor tasks may help differentiating between actual effects of reduced visual acuity on eye–hand coordination in individuals with similar levels of impairment of visual acuity.