RESUMO
PURPOSE: To evaluate the functional magnetic resonance imaging (fMRI) response to binocular visual stimulation and the association thereof with structural ocular findings and psychophysical test results in patients with glaucoma, and controls. METHODS: Cross-sectional study. Participants underwent a complete ophthalmic examination, including Humphrey 24-2 visual field (VF) testing and optical coherence tomography. Binocular VF in each quadrant was determined using an integrated method. Patients with glaucoma were assigned to three subgroups: initial, asymmetrical and severe glaucoma. Regions of interest (ROIs) were determined anatomically. fMRI (3 T) was performed using a bilaterally presented polar angle stimulus, and the accompanying changes in blood oxygen level-dependent (BOLD) signals were obtained from the occipital poles and calcarine ROIs. We used generalized estimation equation models to compare anatomical and functional data between the groups. RESULTS: A total of 25 subjects were enrolled, of whom 17 had glaucoma and 8 were controls. Significant associations between quadrant binocular VF sensitivities and fMRI responses were found in the occipital pole ROIs (p = 0.033) and the calcarine ROIs (p = 0.045). In glaucoma severity subgroup analysis, retinal nerve fiber layer (RNFL) thickness was associated with the BOLD response of the calcarine and occipital pole ROIs (p = 0.002 and 0.026, respectively). The initial and asymmetrical glaucoma subgroups had similar binocular VF sensitivities and RNFL thicknesses, but distinct BOLD responses. CONCLUSIONS: The response of the visual cortex to binocular stimulation was associated with binocular VF sensitivity. RNFL thickness was associated with the BOLD response of the calcarine and occipital pole ROIs.
Assuntos
Glaucoma/patologia , Glaucoma/fisiopatologia , Córtex Visual/fisiopatologia , Adulto , Idoso , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Nervo Óptico/patologia , Estimulação Luminosa , Psicofísica , Tomografia de Coerência Óptica , Campos VisuaisRESUMO
PURPOSE: The aim of this study was to evaluate the duration of the effect of one single dose of brimonidine tartrate 0.15% on pupil diameter, under scotopic conditions, when applied topically in 1 eye of normal subjects. METHODS: The eyes of 19 normal volunteers were randomized so that 1 eye had 1 drop of brimonidine tartrate 0.15% and the other received no medication. Pupil diameter was measured using an infrared pupillometer. The first measure was obtained before the instillation of brimonidine. After that, four measures, with 2-h intervals, were performed. RESULTS: From 19 participants, 14 were women and 5 were men, with a mean age of 25.05 years (standard deviation, +/- 6.98). Before brimonidine instillation, mean pupil diameter in the control eyes was 5.11 mm, and in the brimonidine eyes it was 5.15 mm. After 8 h, the mean pupil size was 4.01 mm in the treated eyes, and 4.56 mm in the untreated eyes. There was a tendency of miotic effect to be more important on the treated eye, as compared to the control eye in all intervals, but this did not reach statistical significance (P = 0.375). When comparing both eyes, independently of the periods, the treated eye had a smaller diameter than the untreated eye (P = 0.038). The miotic effect was observed for at least 8 h after instillation. CONCLUSIONS: Miotic response of brimonidine tartrate 0.15% lasted for at least 8 h and has a significant effect on the nontreated eye.
Assuntos
Agonistas de Receptores Adrenérgicos alfa 2 , Anti-Hipertensivos/farmacologia , Mióticos/farmacologia , Pupila/efeitos dos fármacos , Quinoxalinas/farmacologia , Administração Tópica , Adulto , Anti-Hipertensivos/administração & dosagem , Tartarato de Brimonidina , Adaptação à Escuridão , Técnicas de Diagnóstico Oftalmológico , Feminino , Humanos , Pressão Intraocular/efeitos dos fármacos , Masculino , Mióticos/administração & dosagem , Soluções Oftálmicas , Quinoxalinas/administração & dosagemRESUMO
PURPOSE: To compare the visual performance in the pseudophakic eye and the phakic eye in four patients who underwent unilateral intraocular lens (IOL) implantation. METHODS: Four patients presenting with unilateral cataract underwent ReSTOR (Alcon Laboratories, Ft Worth, Tex) IOL implantation in their nondominant eye, targeting emmetropia. RESULTS: Uncorrected near visual acuity was >20/32 in all operated eyes and best spectacle-corrected distance visual acuity was 20/16 for two eyes, 20/25 for one eye, and 20/32 for one eye. Reading speed was similar between the eyes, but not for critical print size. Contrast sensitivity was lower in the pseudophakic eyes. Wavefront analysis showed no considerable difference in total high order aberrations, coma, and spherical aberration between eyes for all patients. CONCLUSIONS: In young patients with unilateral cataract surgery, unilateral multifocal IOL implantation provides satisfactory visual acuity and may be considered an alternative treatment option in this patient population.