The effects of blurred visual inputs with different levels on the cerebral activity during free level walking.

Objective: The aim of this study was to evaluate the effects of blurred vision on electrocortical activities at different levels during walking. Materials and methods: A total of 22 healthy volunteers (all men; mean age: 24.4 ± 3.9 years) underwent an electroencephalography (EEG) test synchronous with free level walking. Visual status was simulated by goggles covered by the occlusion foil targeted at a Snellen visual acuity of 20/60 (V0.3), 20/200 (V0.1), and light perception (V0). At each of these conditions, the participants completed barefoot walking for five blocks of 10 m. The EEG signals were recorded by a wireless EEG system with electrodes of interest, namely, Cz, Pz, Oz, O1, and O2. The gait performances were assessed by the Vicon system. Results: During walking with normal vision (V1.0), there were cerebral activities related to visual processing, characterized as higher spectral power of delta (Oz and O2 vs. Cz, Pz, and O1, p ≤ 0.033) and theta (Oz vs. Cz and O1, p = 0.044) bands in occipital regions. Moderately blurred vision (V0.3) would attenuate the predominance of delta- and theta-band activities at Oz and O2, respectively. At the statuses of V0.1 and V0, the higher power of delta (at V0.1 and V0, Oz, and O2 vs. Cz, Pz, and O1, p ≤ 0.047) and theta bands (at V0.1, Oz vs. Cz, p = 0.010; at V0, Oz vs. Cz, Pz, and O1, p ≤ 0.016) emerged again. The cautious gait pattern, characterized by a decrease in gait speed (p < 0.001), a greater amplitude of deviation from the right ahead (p < 0.001), a prolonged stance time (p = 0.001), a restricted range of motion in the hip on the right side (p ≤ 0.010), and an increased knee flexion during stance on the left side (p = 0.014), was only detected at the status of V0. The power of the alpha band at the status of V0 was higher than that at V1.0, V0.3, and V0.1 (p ≤ 0.011). Conclusion: Mildly blurred visual inputs would elicit generalization of low-frequency band activity during walking. In circumstance to no effective visual input, locomotor navigation would rely on cerebral activity related to visual working memory. The threshold to trigger the shift might be the visual status that is as blurred as the level of Snellen visual acuity of 20/200.

Effects of visual restoration on gait performance and kinematics of lower extremities in patients with age-related cataract.

BACKGROUND: Visual inputs are critical for locomotor navigation and sensorimotor integration in the elderly; however, the mechanism needs to be explored intensively. The present study assessed the gait pattern after cataract surgery to investigate the effects of visual restoration on locomotion. METHODS: The prospective study recruited 32 patients (70.1 ±â€Š5.2 years) with bilateral age-related cataracts in the Department of Ophthalmology at Peking University Third Hospital from October 2016 to December 2019. The temporal-spatial gait parameters and kinematic parameters were measured by the Footscan system and inertial measurement units. Paired t -test was employed to compare data normally distributed and Wilcoxon rank-sum test for non-normally distributed. RESULTS: After visual restoration, the walking speed increased by 9.3% (1.19 ±â€Š0.40 m/s vs. 1.09 ±â€Š0.34 m/s, P =0.008) and exhibited an efficient gait pattern with significant decrease in gait cycle (1.02 ±â€Š0.08 s vs. 1.04 ±â€Š0.07 s, P =0.012), stance time (0.66 ±â€Š0.06 s vs. 0.68 ±â€Š0.06 s, P =0.045), and single support time (0.36 ±â€Š0.03 s vs. 0.37 ±â€Š0.02 s, P =0.011). High amplitude of joint motion was detected in the sagittal plane in the left hip (37.6°â€Š±â€Š5.3° vs. 35.5°â€Š±â€Š6.2°, P =0.014), left thigh (38.0°â€Š±â€Š5.2° vs. 36.4°â€Š±â€Š5.8°, P =0.026), left shank (71.9°â€Š±â€Š5.7° vs. 70.1°â€Š±â€Š5.6°, P =0.031), and right knee (59.1°â€Š±â€Š4.8° vs. 56.4°â€Š±â€Š4.8°, P =0.001). The motor symmetry of thigh improved from 8.35 ±â€Š5.30% to 6.30 ±â€Š4.73% ( P =0.042). CONCLUSIONS: The accelerated gait in response to visual restoration is characterized by decreased stance time and increased range of joint motion. Training programs for improving muscle strength of lower extremities might be helpful to facilitate the adaptation to these changes in gait.

The impact of age-related cataracts on colour perception, postoperative recovery and related spectra derived from test of hue perception.

BACKGROUND: Cataract patients were always excluded from studies on ageing of colour vision; thus, effect of age-related cataracts on deterioration of colour perception has not been analysed. In present study, impacts of age-related cataracts on colour discrimination, postoperative recovery and related spectra were investigated. METHODS: In this cohort study, thirty age-related cataract patients scheduled for binocular surgery and 30 elderly volunteers were enrolled. Colour discrimination under photopic (1000 lx) and mesopic (40 lx) conditions was evaluated with Farnsworth-Munsell 100-hue test. The total error score (TES) and partial error score (PES) were calculated. RESULTS: Preoperatively, the TES in the patient group was 129.7 ± 59.5 at 1000 lx and 194.6 ± 74.5 at 40 lx, exhibiting worse discrimination than the volunteer group (TES1000lux = 71.5 ± 37.5 and TES40lux = 113.1 ± 38.8, p ≤ 0.001). Inferior perception were detected in the yellow to green-yellow (Y-GY), green-yellow to green (GY-G), green to blue-green (G-BG) and blue-green to blue (BG-B) colour bands (p ≤ 0.003), corresponding to the 470 nm-580 nm range of the visible light spectrum. Under mesopic conditions, the impact expanded to all colour bands except for yellow-red to yellow (YR-Y). Postoperatively, the TES in the patient group were 80.4 ± 62.4 at 1000 lx and 112.0 ± 85.2 at 40 lx, which were lower than those of the preoperative phase (p ≤ 0.001) but similar to those of the volunteer group (p ≥ 0.505). Postoperative improvement occurred in the Y-GY, GY-G and G-BG colour bands (490 nm to 580 nm) at 1000 lx (p ≤ 0.001) and shifted to the Y-GY, GY-G, G-BG and BG-B colour bands (470 nm to 580 nm) at 40 lx (p ≤ 0.001). Deterioration of hue perception for decrement of illumination was detected in the red to yellow-red (R-YR), Y-GY, G-BG, BG-B, blue to purple-blue (B-PB) and red-purple to red (RP-R) colour bands (450 nm to 500 nm) in the volunteer group (p ≤ 0.002) and the R-YR, G-BG, BG-B, B-PB, PB-P and red-purple to red (RP-R) colour bands (from the short-wavelength end to 500 nm) in the patient group preoperatively (p ≤ 0.001). CONCLUSIONS: Phacoemulsification could effectively rebuild colour perception in patients with age-related cataract. The postoperative benefits were most significant in colour bands corresponding with spectrum from 470 nm to 580 nm.

Significant improvement in dynamic visual acuity after cataract surgery: a promising potential parameter for functional vision.

PURPOSE: Dynamic visual acuity (DVA) is a relatively independent parameter for evaluating the ability to distinguish details of a moving target. The present study has been designed to discuss the extent to which age-related cataract impacts DVA in elderly individuals and to determine whether it could be restored after bilateral phacoemulsification combined with intraocular lens implantation surgery. METHODS: Twenty-six elderly cataract patients scheduled for binocular cataract surgery and 30 elderly volunteers without cataract were enrolled in the study. DVA at 15, 30, 60 and 90 degree per second (dps) was assessed, and velocity-dependent visual acuity decreases between consecutive speed levels were calculated. RESULTS: Compared with the control group, the patient group exhibited significantly worse DVA performance at all speed levels (p<0.001), and the decreases in velocity-dependent visual acuity were more serious in the patient group at the intervals of 0-15 dps (p<0.001), 15-30 dps (p = 0.007) and 30-60 dps (p = 0.008). Postoperatively, DVA performance at every speed level in the patient group clearly improved (p<0.001) and recovered to levels compatible to the control group. The decrease in visual acuity with increasing speed was less pronounced than during the preoperative phase (p0-15 dps = 0.001, p15-30 dps<0.001 and p30-60 dps = 0.001) and became similar to that of the control group. The postoperative visual benefit regarding DVA was more pronounced than the improvement in static visual acuity (p15 dps = 0.001 and p<0.001 at 30 dps, 60 dps and 90 dps). CONCLUSIONS: The impact of age-related cataract on DVA was more severe than its effects on static visual acuity. After cataract surgery, not only static vision of the patients was restored markedly, but also the dynamic vision. DVA could be an important adjunct to the current evaluation system of functional vision, thereby meriting additional attention in clinical assessment.

[Changes of dynamic visual acuity after phacoemulsification combined with intraocular lens implantation].

OBJECTIVE: To compare the spatial resolutions of dynamic optotypes at different speed levels among age-related cataract patients, older people with clear crystalline lenses and senile individuals implanted with intraocular lenses (IOL). METHODS: The control study recruited 24 patients (48 eyes) with age-related cataract scheduled for phacoemulsification surgery in our hospital between Jul. 2011 and Dec. 2011 in the cataract group. Twenty-three older volunteers (46 eyes) with clear crystalline lenses were enrolled in the normal group. The postoperative group consisted of 23 contemporary cases implanted with spherical monofocal non-yellow-tinted IOL and followed up for 3 months postoperatively, of which 5 cases undertook unilateral surgery for normal visual acuity of the contralateral eye. Monocular and binocular best corrected visual acuity at static condition and binocular spatial resolution of optotypes at speeds of 15, 30, 60 and 90 degrees per second (dps) were measured by a logarithmic visual acuity chart. Statistical analysis was performed with student's t test (with Bonferroni correction). RESULTS: Binocular spatial resolutions at speeds of 15, 30, 60 and 90 dps were (0.29 ± 0.16), (0.34 ± 0.17), (0.47 ± 0.19) and (0.52 ± 0.17), respectively, in the cataract group, and (0.04 ± 0.06), (0.06 ± 0.06), (0.12 ± 0.09) and (0.15 ± 0.11), respectively, in the normal group. Resolution of dynamic optotypes at the four speed levels were statistically lower in the cataract group than in the normal group (t = -6.952, -7.558, -8.235, -8.737; P < 0.01). Velocity dependent spatial resolution changes manifested statistically higher values in the cataract group than in the normal group, with (0.14 ± 0.13) versus (0.03 ± 0.05) at the interval between static and 15 dps (t0-15 dps = -3.874, P = 0.001) and (0.13 ± 0.09) versus (0.06 ± 0.07) at the interval between 30 dps and 60 dps (t30-60 dps = -3.113, P = 0.003). In the postoperative group, resolutions of dynamic optotypes at speeds of 15, 30, 60 and 90 dps were (0.03 ± 0.05), (0.05 ± 0.07), (0.11 ± 0.10) and (0.16 ± 0.11), respectively. Dynamic visual acuities at all the four speed levels were statistically higher in the postoperative group than in the cataract group (t = -7.336, -7.673, -8.328, -8.583; P < 0.01) and compatible to that in the normal group (t = 0.669, 0.400, 0.372, -0.504; P > 0.05). Visual acuity differences between consecutive speed levels were comparable between the postoperative group and the normal group (t = 0.586, -0.326, 0.133, -1.600; P > 0.05), while at the interval between static and 15 dps and the interval between 30 dps and 60 dps, the postoperative group exhibited lower visual acuity changes than the cataract group, with (0.03 ± 0.04) versus (0.14 ± 0.13) (t0-15 dps = -4.182, P < 0.01) and (0.05 ± 0.06) versus (0.13 ± 0.09) (t30-60 dps = -3.334, P = 0.002), respectively. CONCLUSIONS: As the optotype's moving speed increased, spatial resolutions declined more rapidly in patients with age-related cataract. Phacoemulsification combined with IOL implantation could effectively restore the spatial resolution of dynamic optotypes.

Punctal plugs versus artificial tears for treating primary Sjögren's syndrome with keratoconjunctivitis SICCA: a comparative observation of their effects on visual function.

To compare the effects of treatment with punctal plugs versus artificial tears on visual function for primary Sjögren's syndrome with dry eye. Forty-two eyes of 42 patients with primary Sjögren's syndrome were enrolled and were allocated randomly into artificial tears (AT) group and punctal plugs (PP) group. Ocular Surface Disease Index (OSDI) was used, and fluorescent staining for tear film break-up time (BUT), the Schirmer test I (STI) and contrast sensitivity was performed before treatment and was repeated 3 months after treatment. A follow-up of 3 months was achieved in 40 eyes of 40 patients, including 19 eyes in artificial tears group and 21 eyes in punctal plugs group. Statistically significant improvements were observed in the OSDI scores (AT: 52.6 ± 5.7, 15.9 ± 4.2; PP: 55.8 ± 4.9, 15.1 ± 4.2), corneal fluorescein staining scores (AT: 2.60 ± 1.76, 0.30 ± 0.57; PP: 1.91 ± 1.60, 0.09 ± 0.29), STI (AT: 3.85 ± 2.03, 8.95 ± 2.72; PP: 3.36 ± 1.62, 11.41 ± 2.65), and BUT (AT: 2.60 ± 1.39, 6.00 ± 1.81; PP: 2.27 ± 1.12, 7.82 ± 1.84) after treatment compared to those of pre-treatment. The values of STI (AT: 5.10 ± 1.80; PP: 8.05 ± 1.53) and BUT (AT: 3.40 ± 1.31; PP: 5.68 ± 1.13) in punctal plugs group were significantly more improved than those in the artificial tears group. The medium- and high-level frequencies contrast sensitivities were greatly improved in simulated daylight, night, and glare disability conditions after treatment with artificial tears and punctal plugs. However, the changes in contrast sensitivity did not significantly differ between groups. Both artificial tears and punctal plugs relieved dry eye symptoms, repaired corneal lesions, enhanced tear film stability, and improved contrast sensitivity. Punctal plugs could improve tear film stability and elongate the BUT better than artificial tears.

Combination of retinal pigment epithelium cell-conditioned medium and photoreceptor outer segments stimulate mesenchymal stem cell differentiation toward a functional retinal pigment epithelium cell phenotype.

Recent studies have suggested that bone marrow-derived mesenchymal stem cells (BMMSCs) are capable of retinal tissue-specific differentiation but not retinal pigment epithelium (RPE) cell-specific differentiation. Photoreceptor outer segments (POS) contribute to RPE development and maturation. However, there has been no standard culture system that fosters the differentiation of BMMSCs into mature RPE cells in vitro. In this study, we investigated if the soluble factors from RPE cells and POS could differentiate BMMSCs into cells having a phenotype characteristic of RPE cells. Rat BMMSCs were separately co-cultured with RPE cells, or they were exposed to either control medium, RPE cell-conditioned medium (RPECM), POS, or a combination of RPECM and POS (RPECM-POS). After 7 days, the cells were analyzed for morphology and the expression of RPE markers (cytokeratin 8, CRALBP, and RPE65) to assess the RPE differentiation. Significantly higher pigment accumulation and increased protein expression of the three markers were seen in cells cultured in RPECM-POS than in other treated cultures. Furthermore, the RPECM-POS-treated cultures displayed ultrastructural features typical of RPE cells, expressed RPE cell functional proteins, and had the capability to phagocytose POS. Together, theses results suggest the combination of RPECM and POS stimulate BMMSCs differentiation toward a functional RPE phenotype. Our results provide the foundation for a new route to RPE regenerative therapy involving BMMSCs. Future work isolating the active agent in RPECM and POS would be useful in therapies for RPE diseases or in developing appropriately pre-differentiated BMMSCs for tissue-engineered RPE reconstruction.

Punctal plugs versus artificial tears for treating dry eye: a comparative observation of their effects on contrast sensitivity.

This study aimed to compare the effects of treatment with punctal plugs versus artificial tears on visual function and tear film stability for dry eye. A total of 56 consecutive eyes of 28 dry eye patients observed at our clinic from May to October in 2009 were divided into two groups. One group (32 eyes of 16 patients) was treated with artificial tears, and punctal plugs were used in the other group (24 eyes of 12 patients). A questionnaire was used in these patients before treatment and was repeated 2 weeks after treatment. Fluorescent staining for tear film break-up time (BUT), the Schirmer test I (STI), and contrast sensitivity was performed at the same time. The questionnaire indicated that all patients complained about the uncomfortable symptoms associated with dry eye. These symptoms were relieved after the application of artificial tears or punctal plugs, and there was no significant difference between these two groups. We found that the corneal fluorescent staining disappeared after treatment. The BUT was improved significantly after treatment in both groups, but the improvement was greater in patients who received punctal plugs than those that received artificial tears. There was no remarkable change in the STI in the artificial tears group, but a significant change was observed in the punctal plugs group. The contrast sensitivities were greatly improved in simulated daylight, night, and glare disability conditions after treatment with artificial tears and punctal plugs. However, the changes in contrast sensitivity did not significantly differ between groups. Both artificial tears and punctal plugs relieved dry eye symptoms, repaired corneal lesions, enhanced tear film stability, and improved contrast sensitivity. Punctal plugs could improve tear film stability and elongate the BUT better than artificial tears.

Color discrimination by patients with different types of light-filtering intraocular lenses.

PURPOSE: To evaluate photopic and mesopic color discrimination in patients with different types of light-filtering intraocular lenses (IOLs). SETTING: Peking University Third Hospital, Peking University Eye Center, Beijing, China. METHODS: Cataract patients with different types of IOLs were enrolled 3 months postoperatively. Overall and partial color discrimination under photopic (1000 lux) and mesopic (40 lux) conditions were evaluated with the Farnsworth-Munsell (FM) 100-hue test. Corrected distance visual acuity (CDVA) was tested under both conditions. Subjective visual quality was assessed with the 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25). RESULTS: The study evaluated 43 patients with a blue light-filtering IOL (15 photochromic, 13 yellow tinted) or an IOL filtering ultraviolet light only (n = 15). The difference in the FM 100-hue total error scores under photopic or mesopic conditions was not statistically significant between groups. There were no statistically significant differences in partial error scores in the 10 bands of the FM 100-hue color circle under photopic conditions. Under mesopic condition, there were statistically significant differences in partial error scores in the green to blue-green band (color caps 36 to 46) and the blue-green to blue band (color caps 46 to 54) (P = .005 and P = .030, respectively). There were no statistically significant differences in mean overall or subheading NEI VFQ-25 scores. CONCLUSIONS: Filtering blue lights under mesopic conditions seemed to modify color discrimination in the green-to-blue bands postoperatively. The modification did not disturb overall color discrimination or cause subjective discomfort.