The influence of whole-body vibration, media, and artificial lighting on eye-movement during reading / A influência da vibração de corpo inteiro, da mídia e da iluminação artificial no movimento dos olhos durante tarefas de leitura

ABSTRACT Objective: To evaluate if participants, subjected to whole-body vibration, two different types of media (paper versus tablet) and two lighting environments (fluorescent versus LED), present a difference in eye-movement parameters during reading tasks. Methods: Fourteen adults silently read two different texts in each one of the eight randomized testing conditions (whole-body vibration versus media versus lighting), resulting in 16 different texts read per individual. Whole-body vibration was applied in the vertical direction, 5Hz and 0.8 m/s2 root-mean-square amplitude, a condition similar to those experienced by forklift truck drivers. Participants were in a sitting position with a backrest. An eye-tracker evaluated the eye-movements during the reading task. Results: Whole-body vibration significantly reduced the number of ocular fixations, and cross-correlation; and increased the reading efficiency, fixation duration, directional attack, and binocular anomalies. Neither the type of media nor the lighting environment interfered significantly with the eye-movements, both in situations with and without vibration. Conclusion: The results indicate that whole-body vibration interfered in the eye-movements during the reading task. This may impose a difficulty to process the visual information and to synchronously coordinate the binocular movements under vibration environments.

RESUMO Objetivo: Avaliar se participantes submetidos à vibração de corpo inteiro, a dois tipos diferentes de mídia (papel versus tablet) e a dois ambientes de iluminação (fluorescente versus LED) apresentam diferença nos parâmetros de movimento dos olhos durante tarefas de leitura. Métodos: Quatorze adultos leram silenciosamente dois textos diferentes em cada uma das oito condições de teste (vibração de corpo inteiro versus mídia versus iluminação), de forma aleatória, resultando em 16 textos diferentes lidos por indivíduo. A vibração de corpo inteiro foi aplicada no sentido vertical, com amplitude de 5Hz e 0,8m/s² da raiz do valor quadrático médio, em condição semelhante às vivenciadas pelos motoristas de empilhadeiras. Os participantes permaneceram em postura sentada com encosto. Um rastreador ocular avaliou os movimentos oculares durante a leitura. Resultados: A vibração de corpo inteiro reduziu significativamente o número de fixações oculares e a correlação cruzada entre os olhos e aumentou a eficiência de leitura, duração da fixação, ataque direcional e anomalias binoculares. Nem o tipo de mídia nem as condições de ambientes de iluminação interferiram significativamente nos movimentos oculares, tanto em situações com ou sem vibração. Conclusão: Os resultados indicam que a Vibração de Corpo Inteiro pode interferir nos movimentos oculares durante a leitura. Isso pode impor uma dificuldade no processamento da informação visual e na coordenação síncrona dos movimentos binoculares em ambientes de vibração.

Correlation of foveal avascular zone size with visual acuity and metamorphopsia in idiopathic macular epiretinal membrane eyes using optical coherence tomography angiography / 中华眼底病杂志

Objective To analyze the correlation of foveal avascular zone (FAZ) size with visual acuity and metamorphopsia in idiopathic macular epiretinal membrane (IMEM) eyes.Methods This is a cross-sectional study, including 43 patients (43 eyes) with IMEM (IMEM group) and 35 health subjects (35 eyes) as control group. The best corrected visual acuity (BCVA) was measured using the international standard visual acuity chart, and the results were converted to the logarithm of the minimum angle of resolution (logMAR) visual acuity. The severity of metamorphopsia was measured using M-charts. The FAZ areas were estimated with optical coherence tomography angiography (OCTA) in both the superficial and deep capillary plexus layers. The central macular thickness (CMT) was assessed with spectral-domain optical coherence tomography. There was no difference of logMAR BCVA and CMT between two groups (Z=?7.379, ?7.560;P<0.001). The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between FAZ areas and visual acuity as well as metamorphopsia.Results The FAZ area in superficial and deep capillary plexus in IMEM group were smaller than those in control group (t=?30.316, ?27.606;P<0.001). In IMEM group, the mean M-score was 0.41±0.32; the horizontal and vertical M-score were 0.49±0.40 and 0.32±0.29, respectively. The horizontal M-score was higher than vertical M-score with the significant difference (Z=?2.000,P=0.046). In IMEM group, the FAZ area in superficial capillary plexus correlated inversely with metamorphopsia (r=?0.709,P<0.001); the FAZ area in deep capillary plexus correlated inversely with metamorphopsia and BCVA (r=?0.533, ?0.838;P<0.001).Conclusions The FAZ areas are significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ areas are correlated with metamorphopsia, and deep FAZ area is also correlated with BCVA.

Metamorphopsia and vision-related quality of life and its influencing factor after surgical treatment of idiopathic macular hole / 中华眼底病杂志

Objective To evaluate metamorphopsia and vision-related quality of life (VRQoL) and its influencing factor after vitrectomy for idiopathic macular hole (IMH).Methods This is a prospective and nonrandomized clinical cohort study.Thirty eyes of 30 IMH patients who received vitrectomy and inner limited membrane (ILM) peeling were included.The best-corrected visual acuity (BCVA),medical refraction test and optical coherence tomography (OCT) were performed.BCVA was recorded as logarithm of the minimum angle of resolution (logMAR).The macular hole index (MHI) was measured using OCT.The average logMAR BCVA and MHI in suffering eyes at baseline were 1.02± 0.07 and 0.47 ± 0.02,respectively.The uncorrected visual acuity of the fellow eyes was less than 0.1.Follow-up period was longer than 6 months.At 6 months after surgery,the central retinal thickness (CRT) was measured by OCT;vertical and horizontal metamorphopsia were measured by metamorphopsia charts;VRQoL was evaluated by Chinese VRQoL-25.Spearman correlation analysis was performed to analyze the relationship of VRQoL and postoperative BCVA,metamorphopsia and preoperative MHI.Results At 6 months after surgery,macular hole closure was confirmed by OCT in all patients.The vertical and horizontal metamorphopsia were (0.17± 0.03)° and (0.11 ± 0.03)°,respectively.The VRQoL-25 composite score was 79.81 ± 1.29.The average BCVA was 0.59±0.05.The average CRT was (155.10± 6.27) μm.The postoperative VRQoL was positive correlated with preoperative MHI (r=0.491,P=0.002),and negative correlated with preoperative BCVA (r=-0.445,P=0.014),postoperative BCVA (r=-0.530,P=0.003) and postoperative metamorphopsia (r=-0.532,P=0.006),but not correlated with the postoperative CRT (r=0.231,P＞0.05).Conclusions IMH patients improved their visual acuity after surgery,but still have metamorphopsia.VRQoL was negative correlated with metamorphopsia,positive correlated with preoperative MHI.

Examination of binocular disparity information of normal vision children / 中华全科医师杂志

To explore the binocular disparity information for children with a normal vision based on computer-assisted evaluation system.We examined the random dot zero-order disparity,line zero-order disparity,2nd-order disparity and random dot motion parallax for 97 children with normal vision.And 94 children reached 100″ vision disparity both in random dot zero-order disparity and line zero-order disparity (pass rate of 96.9％) ; all 94 cases passed the 2nd-order disparity and random dot motion parallax.Thus children with a normal vision develop their stereopsis.

Real Stereopsis Test Using a Three-Dimensional Display with Tridef Software

PURPOSE: To investigate horizontal image disparity in three-dimensional (3-D) perception using 3-D animations in normal control patients and patients with intermittent exotropia, anisometropic amblyopia, and partially accommodative esotropia. MATERIALS AND METHODS: A total of 133 subjects were included. Stereopsis was measured using the Titmus Stereo test (Stereo Optical Inc., Chicago, IL, USA) and a 3-D stereopsis test with a 15 inch 3-D display laptop, adjusting 3-D parameters of 0 mm horizontal disparity to 15 mm horizontal disparity. RESULTS: When compared with normal controls, the average threshold of the 3-D stereopsis test was significantly reduced for esotropia patients (p<0.001) and for anisometric amblyopia patients (p<0.001), compared to normal controls. No significant difference was observed between normal controls and intermittent exotropia patients (p=0.082). The 3-D stereopsis test was correlated with the Titmus Stereo test (Spearman's rho=0.690, p<0.001). Mean difference in stereoacuity was 1.323 log seconds of arc (95% limits of agreement: 0.486 to 2.112), and 125 (92.5%) patients were within the limits of agreement. CONCLUSION: This study demonstrated that a 3-D stereopsis test with animation is highly correlated with the Titmus Stereo test; nevertheless, 3-D stereopsis with animations generates more image disparities than the conventional Titmus Stereo test. The 3-D stereopsis test is highly predictive for estimating real stereopsis in a 3-D movie theater.

Perceptual filling-in of stereoscopically presented targets

PURPOSE: To investigate the influence of parametric variation on the filling-in latency of stereoscopically presented stimuli. METHODS: Anaglyphs were created using two circular patches of 0.3° diameter, 0.5° disparity and 6° eccentricity from fixation point. Targets were presented at the visual field midline, 90° and 270° positions, with crossed and uncrossed disparity. The time elapsed for disappearance of the target under voluntary steady fixation was computed. Eighteen subjects tested. RESULTS: There was no significant difference between crossed and uncrossed disparities, nor between near or far from the vertical horopter line. The significant difference was between upper and lower visual field positions. CONCLUSION: The results show that: (i) stereoscopic presentation does not influence the target filling-in latency; (ii) differences between dorsal and ventral visual stream might influence target filling-in latency.

OBJETIVO: Investigar a influência da variação de parâmetros estereoscópicos na latência de preenchimento perceptual de estímulos 3D. MÉTODOS: Criados anáglifos com dois discos de 0,3° de diâmetro, 0,5° de disparidade e 6° de excentricidade do ponto central de fixação. Estímulos foram apresentados na linha central do campo visual, nas posições 90° e 270°, com disparidade cruzada e não cruzada. Registrado o tempo gasto para o preenchimento do estímulo sob fixação estável. Testados dezoito indivíduos. RESULTADOS: Não houve diferença significativa entre as disparidades cruzada e não cruzada, nem entre perto e longe da linha do horóptero vertical. Houve diferença significativa entre posição superior e inferior do campo visual. CONCLUSÕES: Os resultados mostram que: (i) a apresentação estereoscópica não tem influência na latência de preenchimento perceptual, (ii) diferenças entre o sistema visual dorsal e ventral podem influenciar a latência de preenchimento perceptual.

Causes of stereoscopic function abnormality in elderly patients after the cataract extraction with intraocular lens implantation / 中华老年医学杂志

Objective To analyze the reasons and mechanisms of stereoscopic function abnormality in elder patients after the cataract extraction with intraocular lens implantation. Methods 150 cases with artificial lens implantation were randomly selected.Routine eye examinations were carried out and the associated refractive error and presbyopia were corrected.Bilateral simultaneous visual perception and fusion function were examined.The stereoscopic function was tested using "the stereoscopic function examination diagram"created by Yan Shao-ming.Ninety-seven patients who were found to have unrecover-ed or abnormal stereoscopic function were enrolled for analysis. Results In these 97 cases,53(54.6%)were found to have preexisting eye disorders that could affect visual acuity and binocular single vision before the operation.Macular problem was the most prevalent problem in this group.Twenty-seven(27.8%)patients had complicated with corneal astigmatism,after cataract,paralysing strabismus and diplopia as well as macular edema after the operation.In addition,the contralateral unoperated cataract in 17(17.5%)patients and post-operative anisometropia in 9(9.3%)patients were also the causes of stereoscopic function abnormality.There was no reason could be identified in 8 cases. Conclusions The pre-existing eye disorders before lenses implantation,complications of the operation,contralateral unoperated cataract and anisometropia are all the major factors that affect visual acuity recovery and bilateral stereoscopic function rehabilitation.