Noninvasive transorbital alternating current stimulation improves subjective visual functioning and vision-related quality of life in optic neuropathy.

BACKGROUND: Noninvasive repetitive transorbital alternating current stimulation (rtACS) can improve visual field size in patients with optic nerve damage, but it is not known if this is of subjective relevance. We now assessed patient reported outcomes to determine the association between visual field changes and vision-related quality of life (QoL). METHODS: Patients having visual field impairments long after optic nerve damage (mean lesion age 5.5 years) were randomly assigned to a rtACS (n = 24) or sham stimulation group (n = 18). Visual fields and patient reported outcome measures (vision-related QoL: National Eye Institute Visual Function Questionnaire, NEI-VFQ and health-related QoL: Short Form Health Survey, SF-36) were collected before and after a 10-day treatment course with daily sessions of 20 to 40 minutes. The primary outcome measure was the percent change from baseline of detection ability (DA) in defective visual field sectors as defined by computer-based high resolution perimetry (HRP). Secondary outcome parameters included further HRP parameters as well as static and kinetic perimetry results. Changes in QoL measures were correlated with changes in primary and secondary outcome measures in both groups. RESULTS: DA increase in the defective visual field was significantly larger after rtACS (41.1 ± 78.9%, M ± SD) than after sham stimulation (13.6 ± 26.3%), P < 0.05. While there was a significant increase of DA in the whole tested HRP visual field after rtACS (26.8 ± 76.7%, P < 0.05), DA in sham-stimulation patients remained largely unchanged (2.7 ± 20.2%, ns). Results of secondary outcome measures (static and kinetic perimetry) provided further evidence of rtACS efficacy. Improvements in NEI-VFQ subscale "general vision" were observed in both groups but were larger in the rtACS group (11.3 ± 13.5, Z = -3.21, P < 0.001) than in the sham group (4.2 ± 9.4, Z = -1.73, P < 0.05) with a significant difference between groups (Z = -1.71, P < 0.05). DA change and some NEI-VFQ domains were correlated (r = 0.29, P < 0.05), but no significant correlations were observed between DA and SF-36 results. CONCLUSIONS: rtACS facilitates vision restoration after unilateral, long-term optic nerve lesion as assessed both by objective DA changes and improvements in some NEI-VFQ subscales. Both were positively but low correlated, which suggests that factors other than visual field size also contribute to improved vision-related QoL.

Parafoveal vision impairments and their influence on reading performance and self-evaluated reading abilities.

BACKGROUND AND PURPOSE: Patients with homonymous hemianopic field defects (HFD) after postchiasmatic cerebral brain injuries often complain about impairments in daily life activities, particularly problems in reading, and show considerable reductions of vision-related quality of life (QoL). This study aimed to assess the relation of "objective" reading performance and self-reported "subjective" reading abilities; it was further investigated whether parafoveal HFD characteristics have an impact on both parameters. METHODS: In postchiasmatic-lesioned subjects with HFD (n = 43), "objective" reading performance was measured with Radner-Reading-Charts (reading speed, reading acuity). Vision-related QoL was assessed by the National-Eye-Institute-Visual-Function-Questionnaire (NEI-VFQ). Four reading-relevant NEI-VFQ items that assessed "subjective" reading abilities were separately analyzed. Macular sparing measures were derived from campimetry (+/-16 degrees vertical, +/-21.5 degrees horizontal); i.e., the vertical HFD border between +/-2 degrees and the proportion of intact parafoveal visual field within the "reading window". Since macular sparing may be a perimetric artefact, eye movements during campimetry were recorded in 26 subjects. RESULTS: Mean reading speed of the total sample (90.72 +/- 33.96 words per minute) was considerably reduced, as was the patients' vision-related QoL, which was revealed by diminished NEI-VFQ scores. Reading acuity was 0.12 +/- 0.13 LogRAD (0.81 +/- 0.26 according to the decimal system). There were significant but weak correlations between reading acuity and speed with all reading-relevant NEI-VFQ-items (r-range, reading acuity: -0.57 to -0.38, reading speed: 0.33 to 0.43) and 7/12 NEI-VFQ-subscales (r-range, reading acuity: -0.47 to -0.33, reading speed: 0.31 to 0.40). The intact parafoveal visual field correlated significantly with 2/4 reading-related NEI-VFQ-items and with 4/12 NEI-VFQ-subscales (r-range 0.31 to 0.52). Reading acuity and mean reading speed were both correlated with fixation accuracy during campimetry (r = -0.38 and 0.45). Correlations of spared areas between +2 degrees to -2 degrees and the relative and absolute defect HFD border with reading speed, but not reading acuity, tended to significance. Subjects deviated from the campimetric fixation mark in a SD-range of +/-5.2 degrees vertically and +/-6.5 degrees horizontally but eye movement ranges were not correlated with macular sparing measures. CONCLUSIONS: Patients with HFD showed severely reduced reading speed, which was reflected in subjectively diminished reading performance, and reduced reading-related QoL parameters. Larger areas of functionally intact parafoveal vision were associated with better reading performance. Although eye movements occurred during campimetry, these did not seem to constitute an artificially enlarged area of parafoveal intact vision.