Visual field tests are routinely used for the detection and management of glaucoma. This thesis focuses on monitoring the vigilance during perimetry with pupil dynamics (pupillary movements, blinks) in glaucoma patients and the performance of using subsets of standard test patterns at detecting glaucomatous field loss. It describes the spatial pattern of visual field changes in diabetic retinopathy patients after treatment and the usage of multispectral imaging of the optic nerve head in glaucoma patients.The first investigation evaluated the use of pupillary parameters (pupil size and amplitude of pupillary oscillations) to monitor vigilance during perimetry in comparison to electroencephalography. A significant correlation was observed between the decreased pupil size and increased slow brain activities (theta and alpha). The inter-test threshold variability correlated with the pupil miosis.Another investigation explored blinks during a perimetric test and their relationship to the variability of threshold sensitivity in glaucoma patients. A wide range of blink frequencies was observed in glaucoma patients during perimetry and the timing of blinks was correlated with the stimuli presentations when they were supra-threshold. No significant relationship was observed between the threshold sensitivity variability and blink parameters (frequency, duration and microsleep numbers).The third investigation evaluated the use of subset of the 24-2 visual field test pattern at detecting glaucomatous field loss. A high sensitivity and specificity was observed when using subsets of the 24-2 pattern and test locations optimized by the positive predictive values showed a better performance than the test locations in random sequences.With the usage of a self-organized mapping method, nine spatial patterns of visual field loss in untreated diabetic retinopathy patients were classified. After laser treatment, a significant improvement on the spatial patterns of field loss and global indices was found.In the multispectral imaging study, the haemoglobin dependent differential light absorption (DLA) properties of the glaucomatous optic nerve head was evaluated with multispectral imaging. Change of DLA after medical hypotensive treatment was graded by five experts and no difference was observed in most of the patients.

Orientadores: Keila Miriam Monteiro de Carvalho, Vital Paulino Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T23:17:16Z (GMT). No. of bitstreams: 1 Guimaraes_AronBarbosaCaixeta_M.pdf: 3821530 bytes, checksum: ac0531c33178347f86a1927a76e2ce56 (MD5) Previous issue date: 2015 / Resumo: Investigar a influência dos defeitos do campo visual (CV) no desempenho de leitura de pacientes com glaucoma primário de ângulo aberto (GPAA) e 20/20 de acuidade visual. Métodos: Realizou-se um estudo transversal em 35 pacientes com GPAA e 35 controles pareados por idade, todos com 20/20 de acuidade visual em pelo menos um dos olhos. Os indivíduos foram submetidos à biomicroscopia com lâmpada de fenda, tonometria de aplanação, gonioscopia, exame do nervo óptico com uma lente de 78 dioptrias e perimetria computadorizada com Humphrey Field Analyzer (Sita Standard 24-2). A velocidade de leitura monocular foi avaliada usando-se a tabela Minnesota Low Vision Reading Test (MNREAD) em uma versão traduzida e validada para o português. No grupo dos pacientes com glaucoma, caso ambos os olhos fossem elegíveis, o olho com maior defeito de CV, representado pelo menor Mean Deviation (MD) foi incluído. No grupo controle o olho participante foi escolhido aleatoriamente. Os parâmetros obtidos através do MNREAD foram a Velocidade Máxima de Leitura (VML), o Tamanho Crítico de Letra (TCL) e a Acuidade de Leitura (AL). Resultados: A média da VML nos pacientes com glaucoma (125,04 ± 38,36 palavras por minuto) foi significativamente menor do que no grupo controle (183,95 ± 15,54, p = 0,001). A média do TCL nos pacientes (0,09 ± 0,16 palavras por minuto) foi significativamente maior do que no grupo controle (-0,01 ± 0,07, p = 0,003). A média da AL nos pacientes (-0,17± 0,07) não apresentou diferença estatisticamente significativa em relação ao grupo controle (-0,19 ± 0,07, p = 0,469). A VML apresentou uma correlação positiva muito forte com MD nos pacientes com glaucoma (r = 0,954, p = 0,01). TCL teve uma correlação negativa muito forte com MD no grupo dos pacientes (r = -0,827, p = 0,01). AL apresentou uma correlação negativa substancial com MD no grupo dos pacientes (r = -0,624, p = 0,01). No grupo controle verificou-se correlação negativa baixa entre VML e MD (r = -0,132, p = 0,449), correlação negativa ínfima entre AL e MD (r = -0,076, p = 0,664) e uma correlação negativa moderada entre TCL e MD (r = -0,375, p = 0,026). Conclusões: Pacientes com glaucoma e acuidade visual 20/20 apresentam um comprometimento no desempenho de leitura que se relaciona com a gravidade do defeito no CV / Abstract: To investigate the influence of visual field defects on the reading performance of patients with primary open-angle glaucoma (POAG) and 20/20 visual acuity. Methods: This was a Cross-sectional study of 35 POAG patients and 35 age-matched controls, all with 20/20 visual acuity in at least one eye. All individuals underwent slit-lamp biomicroscopy, applanation tonometry, gonioscopy, optic nerve examination with a 78-D lens and automated perimetry performed with the Humphrey Field Analyzer (Sita Standard 24-2). Monocular reading speed was assessed using the Minnesota Low Vision Reading chart (MNREAD) in a translated and validated Portuguese version. In the patient group, if both eyes were eligible, the eye with more advanced visual field defect, characterized by the lowest Mean Deviation (MD), was included. Only one eye of each healthy participant was randomly included in the study. The parameters obtained with the MNREAD were Maximum Reading Speed (MRS), Critical Print Size Size (CPS) and Reading Acuity (RA). Results: Mean MRS in the POAG group (125.04 ± 38.36 words per minute) was significantly lower than in the control group (183.95 ± 15.54; p = 0.001). Mean CPS in the POAG group (0.09 ± 0.16 words per minute) was significantly larger than in the control group (-0.01 ± 0.07; p = 0.003). Mean RA in the POAG group (-0.17 ± 0.07) showed no statistically significant difference from the control group (-0.19 ± 0.07, p = 0.469). MRS presented a very strong positive correlation with visual field MD in the POAG group (r = 0.954, p = 0.01). CPS presented very strong negative correlation with MD in the POAG group (r = -0.827, p = 0.01). RA presented a substantial negative correlation with MD in the POAG group (r = -0.624, p = 0.01). MRS presented a weak negative correlation with visual field MD in the control group (r = -0.132, p = 0.449). RA presented a very weak negative correlation with visual field MD in the control group (r = -0.076, p = 0.664). CPS presented a moderate negative correlation with visual field MD in the control group (r = -0.375, p = 0.026). Conclusions: Glaucoma patients with 20/20 visual acuity show impairment in reading performance that correlates with the severity of the visual field defect / Mestrado / Oftalmologia / Mestre em Ciências Médicas

Un mot est mieux reconnu lorsqu'il est présenté dans le champ visuel droit (CVD) que dans le gauche. La supériorité du CVD peut être expliquée par le rôle de l'hémisphère gauche en lecture et par le sens de lecture pour les langues se lisant de gauche à droite. Cependant la comparaison entre les systèmes d'écriture gauche-droite et droite-gauche ne fournit pas de différences claires et systématiques. Le premier but de ce travail de thèse était de préciser les effets du sens de lecture sur la supériorité du CVD en lecture et d'évaluer si l'influence de l'écriture « environnementale » pouvait modifier les stratégies attentionnelles des lecteurs. Nous avons présenté des mots français et hébreux à des participants bilingues, mais de langue maternelle française ou hébreu, vivant en France ou en Israël. Les résultats ont montré une supériorité du CVD plus importante en français qu'en hébreu dans tous les groupes sauf chez les israéliens vivant en Israël. Il y aurait donc bien un effet de la langue et de l'écriture environnementale sur la supériorité du CVD. Avec d'autres expériences, nous avons également pu évaluer l'effet du contexte expérimental (confrontation des deux langues dans un même bloc d'essais) et de la familiarité linguistique (mots vs pseudomots). / A word is better identified when displayed in the right visual field (RVF) than in the left. The RVF superiority might be explained by the role of the left hemisphere in reading and by reading direction in left-to-right scripts. However the comparison between left-to-right and right-to-left scripts do not provide systemactic and clear differences. The primary goal of this dissertation was to determine the effects of reading direction on the RVF superiority in reading, and assess whether the influence of "environmental" writing could alter the attentional strategies of the readers. French and Hebrew words were displayed to bilingual participants but whose native language was French or Hebrew, living in France or in Israel. Results showed a larger RVF superiority in French than in Hebrew for all groups except among the Israeli group living in Israel. So there would have an effect of language, and environmental writing on the RVF superiority. With further experiments, we were also able to evaluate the effect of experimental context (confrontation of the two languages in the same block of trials) and linguistic familiarity (words vs pseudowords).

yes / Purpose: Inter-individual variance in optic nerve head (ONH) position, axial length and location of the temporal raphe suggest that customizing mapping between visual field locations and optic nerve head sectors for individuals may be clinically useful. Here we quantify the proportion of the population predicted to have structure-function mappings that markedly deviate from “average”, and thus would benefit from customized mapping. Design: Database study and case report Participants: Population database of 2836 eyes from the Beijing Eye Study; single case report of an individual with primary open angle glaucoma Methods: Using the morphometric fundus data of the Beijing Eye Study on 2836 eyes and applying a recently developed model based on axial length and ONH position relative to the fovea, we determined for each measurement location in the 24-2 Humphrey visual field the proportion of eyes for which, in the customized approach as compared to the generalized approach, the mapped ONH sector was shifted into a different sector. We determined the proportion of eyes for which the mapped ONH location was shifted by 15°, 30° or 60°. Main outcome measures: Mapping correspondence between locations in visual field space to localized sectors on the optic nerve head Results: The largest inter-individual differences in mapping are in the nasal step region where the same visual field location can map to either the superior or inferior ONH depending on other anatomical features. For these visual field locations, approximately 12% of eyes showed a mapping opposite to conventional expectations. Conclusions: Anatomically customised mapping shifts the map markedly in approximately 12% of the general population in the nasal step region where visual field locations can map to the opposite pole of the ONH than conventionally considered. Early glaucomatous damage commonly affects this region, hence individually matching structure to function may prove clinically useful for the diagnosis and monitoring of progression within individuals. / Australian Research Council Linkage Project 130100055 (industry partner, Heidelberg Engineering, GmBH, Germany).

yes / Purpose Perimetry is increasingly being used to measure sensitivity at central visual field locations. For many tasks, the central (0°, 0°) location is functionally the most important, however threshold estimates at this location may be affected by masking by the nearby spatial structure of the fixation target. We investigated this effect. Methods First we retrospectively analysed microperimetry (MAIA-2; CenterVue, Padova, Italy) data from 60 healthy subjects, tested on a custom grid with 1° central spacing. We compared sensitivity at (0°, 0°) to the mean sensitivity at the eight adjacent locations. We then prospectively tested 15 further healthy subjects on the same instrument using a cross-shaped test pattern with 1° spacing. Testing was carried out with and without the central fixation target, and sensitivity estimates at (0°, 0°) were compared. We also compared sensitivity at (0°, 0°) to the mean of the adjacent four locations in each condition. Three subjects undertook 10 repeated tests with the fixation target in place to assess within-subject variability of the effect. Results In the retrospective analysis, central sensitivity was median 2.8 dB lower (95% range 0.1–8.8 dB lower, p < 0.0001) than the mean of the adjacent locations. In the prospective study, central sensitivity was median 2.0 dB lower with the fixation target vs without (95% range 0.4–4.7 dB lower, p = 0.0011). With the fixation target in place central sensitivity was median 2.5 dB lower than mean sensitivity of adjacent locations (95% range 0.8–4.2 dB lower, p = 0.0007), whilst without the fixation target there was no difference (mean 0.4 dB lower, S.D. 0.9 dB, p = 0.15). These differences could not be explained by reduced fixation stability. Mean within subject standard deviation in the difference between central and adjacent locations' sensitivity was 1.84 dB for the repeated tests. Conclusions Perimetric sensitivity estimates from the central (0°, 0°) location are, on-average, reduced by 2 to 3 dB, corresponding to a 60–100% increase in stimulus luminance at threshold. This effect can be explained by masking by the nearby fixation target. The considerable within- and between-subject variability in magnitude, and the unknown effects of disease may hamper attempts to compensate threshold estimates for this effect. Clinicians should interpret central perimetric sensitivity estimates with caution, especially in patients with reduced sensitivity due to disease.

No / To investigate the relationship between neuroretinal rim (NRR) differential light absorption (DLA, a measure of spectral absorption properties) and visual field (VF) sensitivity in primary open-angle glaucoma (POAG). atients diagnosed with (n = 22) or suspected of having (n = 7) POAG were imaged with a multispectral system incorporating a modified digital fundus camera, 250-W tungsten-halogen lamp, and fast-tuneable liquid crystal filter. Five images were captured sequentially within 1.0 second at wavelengths selected according to absorption properties of hemoglobin (range, 570–610 nm), and a Beer-Lambert law model was used to produce DLA maps of residual NRR from the images. Patients also underwent VF testing. Differences in NRR DLA in vertically opposing 180° and 45° sectors either side of the horizontal midline were compared with corresponding differences in VF sensitivity on both decibel and linear scales by Spearman's rank correlation. The decibel VF sensitivity scale showed significant relationships between superior–inferior NRR DLA difference and sensitivity differences between corresponding VF areas in 180° NRR sectors (Spearman ρ = 0.68; P < 0.0001), superior-/inferior-temporal 45° NRR sectors (ρ = 0.57; P < 0.002), and superior-/inferior-nasal 45° NRR sectors (ρ = 0.59; P < 0.001). Using the linear VF sensitivity scale significant relationships were found for 180° NRR sectors (ρ = 0.62; P < 0.0002) and superior–inferior–nasal 45° NRR sectors (ρ = 0.53; P < 0.002). No significant difference was found between correlations using the linear or decibel VF sensitivity scales. Residual NRR DLA is related to VF sensitivity in POAG. Multispectral imaging may provide clinically important information for the assessment and management of POAG. / College of Optometrists (UK) PhD Studentship (JD), Central Manchester NHS Foundation Trust Grant RO1180, the Manchester Academic Health Sciences Centre (MAHSC), and the NIHR Manchester Biomedical Research Centre.

Yes / Purpose: To investigate how well visual field sensitivity predicts visual acuity at the same locations in macular disease, and to assess whether such predictions may be useful for selecting an optimum area for fixation training. Methods: Visual field sensitivity and acuity were measured at nine locations in the central 10° in 20 people with AMD and stable foveal fixation. A linear mixed model was constructed to predict acuity from sensitivity, taking into account within-subject effects and eccentricity. Cross validation was used to test the ability to predict acuity from sensitivity in a new patient. Simulations tested whether sensitivity can predict nonfoveal regions with greatest acuity in individual patients. Results: Visual field sensitivity (P < 0.0001), eccentricity (P = 0.007), and random effects of subject on eccentricity (P = 0.043) improved the model. For known subjects, 95% of acuity prediction errors (predicted − measured acuity) fell within −0.21 logMAR to +0.18 logMAR (median +0.00 logMAR). For unknown subjects, cross validation gave 95% of acuity prediction errors within −0.35 logMAR to +0.31 logMAR (median −0.01 logMAR). In simulations, the nonfoveal location with greatest predicted acuity had greatest “true” acuity on median 26% of occasions, and median difference in acuity between the location with greatest predicted acuity and the best possible location was +0.14 logMAR (range +0.04 to +0.17). Conclusions: The relationship between sensitivity and acuity in macular disease is not strongly predictive. The location with greatest sensitivity on microperimetry is unlikely to represent the location with the best visual acuity, even if eccentricity is taken into account. / College of Optometrists Postdoctoral Research Award (JD and ATA; London, UK) and National Institute for Health Research (NIHR) Postdoctoral Fellowship (ATA; London, UK). Presents independent research funded by the NIHR. / Research Development Fund Publication Prize Award winner, August 2018.

The majority of previous research investigating the role of vision in controlling adaptive gait has predominantly focused on over-ground walking or obstacle negotiation. Thus there is a paucity of literature investigating visuomotor control of step descent. This thesis addressed the importance of the lower visual field (lvf) in regulating step descent landing control, and determined when visual feedback is typically used in regulating landing control prior to / during step descent. When step descents were completed from a stationary starting position, with the lvf occluded or degraded, participants adapted their stepping strategy in a manner consistent with being uncertain regarding the precise location of the foot / lower leg relative to the floor. However, these changes in landing control under conditions of lvf occlusion were made without fundamentally altering stepping strategy. This suggests that participants were able to plan the general stepping strategy when only upper visual field cues were available. When lvf was occluded from either 2 or 1 step(s) prior to descending a step during on-going gait, stepping strategy was only affected when the lvf was occluded in the penultimate step. Findings suggest that lvf cues are acquired in the penultimate step / few seconds prior to descent and provide exproprioceptive information of the foot / lower leg relative to the floor which ensures landing is regulated with increased certainty. Findings also highlight the subtle role of online vision used in the latter portion of step descent to 'fine tune' landing control.

Retinitis pigmentosa (RP) is the most common form of inherited retinal degeneration, heterogenous in its clinical presentation and genetic cause. Understanding the short-term disease mechanisms is pivotal for the development of new therapies. Upcoming clinical trials will take genotype-agnostic approaches; therefore, a comprehensive analysis of progression that encompasses many genetic factors will be needed. In this 10-year retrospective cohort study, rates of progression were measured, structurally and functionally, in 85 RP patients seen at the Ottawa Eye Institute. Parameters examined were the ellipsoid zone (EZ) length on an optical coherence tomography (OCT) image, Humphrey and Goldmann visual fields (VF), and full-field and multifocal electroretinograms (ERGs). RP is revealed to have a 1st order exponential decay pattern of loss, with mean rates of decline of 7.65 %/year for ellipsoid zone (EZ) length, 6.35%/year, 4.39%/year, and 1.57%/year for the Humphrey VF 30-2, 24-2, and 10-2 mean deviation (MD) respectively, and 5.22%/year, 7.77%/year, 6.77%/year, 6.80%/year, and 12.45%/year for Goldmann V4e, III4e, I4e, I3e, and I2e isopter lengths, respectively. In cases where different diagnostic tests were conducted within 3 months of each other, the data was analysed to determine if there was a positive correlation between the diagnostic tests. Ellipsoid zone length and Humphrey 24-2 mean deviation exhibited the strongest association with a coefficient of 0.99. The study reveals structural and functional changes in advanced retinitis pigmentosa and presents a protocol for assessing short-term progression.

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