Retinal thickness measurement and evaluation of natural history of the diabetic macular edema through optical coherence tomography
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Data
2009
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Resumo
Purpose: 1) Diagnose, through optical coherence tomography (OCT)
exam, the occurrence of diabetic macular edema in patients with diabetic
retinopathy and visual acuity of 20/40 or better, by measuring the foveal
center point thickness, during one year. 2) Evaluate the edema natural
history, during this period, associating the center point thickness with
hemoglobin A1c and changes in visual acuity. 3) Correlate the obtained
results with the control group. Methods: A prospective study was done,
of a sample of 30 patients with diabetic macular edema and visual acuity
of 20/40 or better. Measurements of the best corrected visual acuity,
hemoglobin A1c level, biomicroscopy with 78-diopter lens, fluorescein
angiogram and optical coherence tomography were made. The retinal
thickness was selected as the main variable. Besides descriptive statistics,
additional tests were applied to analyze the results and determine the
correlation between these variables, such as t-Student, Chi-Square, Tukey
and ANOVA. The relation of optical coherence tomography with visual
acuity and hemoglobin A1c was studied through linear regression. Re-
sults: It was found that there is no significant difference between patients
and normal individuals, for the variables age and gender. The values of
center point thickness found for men were greater than those for women,
showing the influence of gender on that thickness. As many as 83.33%
of the diabetic patients with clinically significant macular edema presented
moderate non-proliferative diabetic retinopathy (NPDR), 10% presented
mild NPDR and 6.66% severe non-proliferative diabetic retinopathy.
Patients under combined treatment of insulin and oral hypoglycemiant
presented influence on the results of center point thickness (through
OCT) and visual acuity. The mean duration of diabetes was 9.63 years.
Values of center point thickness were always found greater for patients
than those for normal eyes. Levels of hemoglobin A1c did not have
influence on the center point thickness data, whereas values of visual
acuity were significantly correlated with it. Conclusion: This study presents
the optical coherence tomography applicability in the detection and
semiologic evaluation of diabetic macular edema in patients with visual
acuity 20/40 or greater, during one year, showing the retinal thickening
in the early stages of diabetic retinopathy. Further, it evidenciated the
correlation between the increase in foveal thickness and the reduction
in visual acuity. Levels of hemoglobin A1c did not influence the center
point thickness data. An early detection of clinically significant macular
edema leads us to a redefinition of the real meaning of incipient retinopathy
and can prevent further significant reduction of vision.
Descrição
Palavras-chave
Diabetic retinopathy, Visual acuity, Macular edema, Tomography, optical coherence, Light coagulation/methods, Fovea centralis, Retinopatia diabética, Acuidade visual, Edema macular, Fóvea central, Tomografia de coerência óptica, Fotocoagulação/métodos
Citação
HANNOUCHE, Rosana Zacarias; ÁVILA, Marcos Pereira de. Retinal thickness measurement and evaluation of natural history of the diabetic macular edema through optical coherence tomography. Arquivos Brasileiros de Oftalmologia, São Paulo, v. 72, n. 4, p. 433-438, 2009.