Effect of retinal image defocus on the thickness of the human choroid
Data(s) |
01/01/2015
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Resumo |
PURPOSE: To describe the time-course and amplitude of changes to sub-foveal choroidal thickness (SFCT) induced by imposed hyperopic and myopic retinal defocus and to compare the responses in emmetropic and myopic subjects. METHODS: Twelve East Asian subjects (age: 18-34 years; six were emmetropic and six had myopia between -2.00 and -5.00 dioptres (D)) viewed a distant target (video movie at 6 m) for 60 min on two separate occasions while optical coherence tomography (OCT) images of the choroid were taken in both eyes every 5 min to monitor SFCT. On each occasion, one eye was optimally corrected for distance with a contact lens while the other eye wore a contact lens imposing either 2.00 D hyperopic or 2.00 D myopic retinal defocus. RESULTS: Baseline SFCT in myopic eyes (mean ± S.D.): 256 ± 42 μm was significantly less than in emmetropic eyes (423 ± 62 μm; p < 0.01) and was correlated with magnitude of myopia (-39 μm per dioptre of myopia, R(2) = 0.67: p < 0.01). Repeated measures anova (General Linear Model) analysis revealed that in both subject groups, 2.00 D of myopic defocus caused a rapid increase in SFCT in the defocussed eye (significant by 10 min, increasing to approximately 20 μm within 60 min: p < 0.01), with little change in the control eye. In contrast, 2.00 D of hyperopic defocus caused a decrease in SFCT in the experimental eye (significant by 20-35 min. SFCT decreased by approximately 20 μm within 60 min: p < 0.01) with little change in the control eye. CONCLUSIONS: Small but significant changes in SFCT (5-8%) were caused by retinal defocus. SFCT increased within 10 min of exposure to 2.00 D of monocular myopic defocus, but decreased more slowly in response to 2.00 D of monocular hyperopic defocus. In our relatively small sample we could detect no difference in the magnitude of changes to SFCT caused by defocus in myopic eyes compared to emmetropic eyes. |
Identificador | |
Idioma(s) |
eng |
Publicador |
Wiley |
Relação |
http://dro.deakin.edu.au/eserv/DU:30074225/backhouse-effectofretinal-2015.pdf http://www.dx.doi.org/10.1111/opo.12218 http://www.ncbi.nlm.nih.gov/pubmed/26010292 |
Direitos |
2015, Wiley |
Palavras-Chave | #choroid #emmetropia #eye #hyperopia #myopia #optical coherence tomography #Science & Technology #Life Sciences & Biomedicine #Ophthalmology #DIFFUSE LUMINANCE FLICKER #FORM-DEPRIVATION MYOPIA #HEAD BLOOD-FLOW #AXIAL LENGTH #INTRAOCULAR-PRESSURE #LENS COMPENSATION #DIURNAL-VARIATION #REFRACTIVE STATE #CONTACT-LENSES |
Tipo |
Journal Article |