ObjectiveTo observe the changes in choroidal thickness in type 2 diabetes patients with diabetic retinopathy (DR). MethodsA total of 227 eyes from 150 type 2 diabetes patients were enrolled in this study. The patients included 67 males (89 eyes) and 83 females (138 eyes). The mean age was (65.6±8.0) years, and the mean diabetes duration was (12.4±6.5) years. All the patients were examined for best corrected visual acuity (BCVA), diopter, slit lamp ophthalmoscopy, indirect ophthalmoscopy and spectral domain optical coherence tomography (SD-OCT) examination. The patients were divided into non-DR (NDR group, 99 eyes), non-proliferative DR (PDR) without macular edema (ME) group (NPDR/ME-group, 64 eyes), non-PDR with ME group (NPDR/ME+ group, 5 eyes), PDR without ME group (PDR/ME-group, 25 eyes), PDR with ME group (PDR/ME+ group, 5 eyes) according to the Early Treatment Diabetic Retinopathy Study. The ones having a history of pan-retinal photocoagulation (PRP) were classified as PRP-DR. Age-matched normal subjects were enrolled as the control group. Sub-foveal choroidal thickness (SFCT) was measured by SD-OCT with enhanced depth imaging (EDI). ResultsMean SFCT was (310.2±54.8), (251.1±81.4), (262.5±83.2), (286.2±76.8) and (327.4±83.1) μm respectively in control, NDR, NPDR/ME-, PDR/ME-and PRP-DR groups. Mean SFCT decreased significantly in NDR and NPDR/ME-group (t=2.754, 2.140; P < 0.05). Mean SFCT in PDR/ME-group was thicker than that in NDR (t=-2.114, P < 0.05). Mean SFCT in PRP-DR group was thicker than that in PDR/ME-group (U=271.500, P < 0.05). ConclusionSFCT decreased during the early course of diabetics and increased significantly as the severity worsened from NDR to PDR, and increased in the early duration after PRP treatment.
ObjectiveTo observe the frequency domain optical coherence tomography (SD-OCT) features of Henle fiber layer (HFL) of health adults in china by changing the angle of the measurement beam. Methods Twenty-four subjects (28 eyes) who showed no abnormalities on routine eye examination were included in the study, including 15 males (16 eyes) and 9 females (12 eyes) with an average age of (35.51±3.54) years old, and mean refraction power of (-0.89±1.15) D. All subjects underwent corrected visual acuity, intraocular pressure, slit lamp microscope, direct ophthalmoscope, visual field and SD-OCT examination. The macular area was scanned by Zeiss Cirrus SD-OCT (5 HD line) single line scan mode. Based on the entry position of the SD-OCT beam through the pupil, the subjects were divided into 3 groups, including group A (center of the pupil), group B (near the temporal edge of the pupil) and group C (near the nasal edge of the pupil). The thickness of outer plexiform layer (OPL), HFL, and outer nuclear layer (ONL) were measured at 0.75 mm, 1.50 mm from the fovea. ResultsWhen entry position of the SD-OCT beam was near the temporal edge of the pupil (group B); there were two layer structures with different signal intensities in the weak reflectivity zones in front of the external limiting membrane (ELM). The signal of the inner layer was slightly higher than the outer layer. The OPL thickness at the decreased side (nasal) increased significantly compared with the other side, but the ONL thickness was significantly thinner than other side. When entry position of the SD-OCT beam was near the nasal edge of the pupil (group C), there were also two layer structures with different signal intensities in the weak reflectivity zones in front of the ELM. The signal of the outer layer was slightly higher than the inner layer. The OPL thickness at the decreased side (temporal) increased significantly compared with the other side, but the ONL thickness was significantly thinner than other side. The OPL thickness at the decreased side was significantly different between these 3 groups (P < 0.01). ConclusionsSD-OCT provided the possibility of distinguishing HFL from the actual ONL by changing the angle of the measurement beam. This finding has great clinical significance for related diseases affecting HFL or ONL.