ObjectivesTo evaluate the reproducibility of Heidelberg retina tomograph (HRT) macular edema module(MEM) measuring the macular retinal thickness.MethodsSixty-two healthy volunteers (9-68 years old) were examined by HRT-II procedure. The retinal signal width (SW) at macula and fovea and macular edema index (E) were recorded for t-test, Pearson linear-correlation analysis. Intra-subject variation repeatedly measured was analyzed with coefficient of variation, 95% tolerance limits of change (TC), and intraclass coefficient of correlation (ICC). ResultsIn healthy individuals, retinal SW was (0.734±0.236) mm at macula，and (0.781±0.243) mm at fovea; macular E was (1.169±0.619). The coefficient of variation repeatedly measured: retinal SW was (8.7±68)%，retinal SW at the fovea was (8.5±6.7)%, and the average was (15.6±13.9)%; 95%TC of intra-subject sequential repeated measurement was 0.131 (8.9%) of retinal SW, 0.137 (10.5%)of fovea SW，and 0.198 (7.4%) of average E. ICC of one individual repeatedly measured by one operator was 0.950 of macular SW, 0.949 of fovea SW, and 0.898 of average edema index.ConclusionsHRT-II MEM is noninvasive, fast and highly reproducible, which provides a new technique to monitor the objective quantification of macular diseases related to retinal thickness. ( Chin J Ocul Fundus Dis, 2005,21:103-105)
Objective To observe the retinal ultrastructure of the human fetal at the age of 9 months, and to investigate the clinical significance of the observation on retinal neuron development during the prenatal period.Methods Four human fetal eyes of 2 fetus at the gestational age of 9 months, including 1 at 35 and the other at 36 weeks, were obtained after termination of pregnancy due to trauma. The gestational ages of the fetus were estimated according to both last menstrual period (LMP) of the pregnant women and the weight/crownheel length of fetus at the delivery. From each eyeball, 4 pieces of retina at the posterior pole were obtained and observed after specimens handling according to the procedure of routine electron microscopy. Eight pieces of retina which were randomly selected from total of 16 pieces of retina in each group were processed and observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Permissions from pregnant women and family members were guaranteed.Results At the gestational age of 9 months, the outer nuclear layer of fetal retina contained 5 to 6 layers of photoreceptor cells (PRC), and sphericallike membrane structures were found outside of the outer limiting membrane (OLM). Among many tightaligned inner segments of PRCs there was zonula adherens of OLM, mitochondrias at inner side of OLM, and cilium at outer side of OLM. Outer segment of PRCs were short and contained a few irregularly arranged disc membrane. Some PRC had a multishaped nucleus in which equal amount of euchromatin and heterochromatin. There were only few and thin axon branches from photoreceptor cells, and very few axons contacted with inner nuclear layer (INL) and no typical synapse was found. The INL contained 4 to 5 layers of cell bodies, in which many cellular nuclear had uneven density of euchromatin and heterochromatin; some were lobulated nucleus with clear karyotheca. In inner plexiform layer (IPL), the nerve cells had small branches, and only little connection among the synapses and few synapse structures were found. Although not many retinal ganglion cells (RGC) existed,RGC had both intact cell membrane and some rough endoplasmic reticulum (RER).The karyotheca of RGC had double-layers structures, and the nucleus was mainly consisted of euchromatin. Internal limiting membrane (ILM) had doublelayer membrane structures, and the wellarranged nerve fiber layer was located at the outer side of ILM, with some micropores on the surface. Conclusions At the gestational age of 9 months, all layers of the human retinal has been formed, but some cell structure and cell connections are not yet mature, suggesting that at this time of period, human retina is still at an important stage of developing and remodeling.
Objective To test the hypothesis that the macular pigment may be a marker of foveal cone function and consequently the structural integrity of foveal cones.Methods Sixteen patients (32 eyes) diagnosed to have Stargardt dystrophy and three patients with full thickness macular holes by clinical criteria were studied with a scanning laser ophthalmoscopy (SLO) comparing argon laser blue and infrared images for the presence or absence of macular pigment (MP) in the fovea. An C++ computer based program was used to evaluate the density of MP. Eyes were graded into three categories: those without foveal macular pigment, those with partial pigment and those with normal amounts of macular pigment. These categories were compared with visual acuity determined by the Snellen chart. Results Thirteen eyes with a visual acuity of 20/200 or worse had no macular pigment in the fovea. Eleven eyes with visual acuity of 20/40 or better had a normal amount of macular pigment in the fovea and 1 eye had partial macular pigment. Eleven eyes with partial macular pigment had intermediary acuity value.Conclusions Foveal macular pigment is closely related to foveal cone acuity and therefore may be a marker for the presence of foveal cones. Infrared light is a sensitive indicator of early macular diseases.(Chin J Ocul Fundus Dis，2003，19：201-268)
Adaptive optics (AO) is a technique to improve the performance of optical systems by reducing the influence of optical aberrations. Combined with scanning laser ophthalmoscope (AOSLO), the aberration of human refractive system can be corrected. Thus, the resolution and quality of imaging can be greatly improved to the cellular level in vivo retina (such as photoreceptor, nerve fibers, vascular parietal cell), therefore the earlier changes of the diseases can be detected. At the same time, microstructure changes of retinal can also be observed during the follow-up of the disease. Due to inherent technical defects of AOSLO, its wide application in clinical practice is limited. With the continuous progress of AO technology and the further improvement of related software functions, the function of the system will become more stronger and will play a more and more important role in scientific research and clinic.
Objective To observe the corneal nerve fibres damage in different stage of diabetic retinopathy (DR) with type 2 diabetes. Methods A cross-sectional study. One hundred and twenty eyes of 120 patients with type 2 diabetes served as diabetes group. According to International Clinical Diabetic Retinopathy Disease Severity Scales (2002), diabetes patients were classified into 4 subgroups: patients without diabetic retinopathy (NDR), patients with mild or moderate non-proliferative diabetic retinopathy (mNPDR), patients with severe non-proliferative diabetic retinopathy (sNPDR) and patients with proliferative diabetic retinopathy (PDR), each subgroup has 30 eyes of 30 patients. Another 30 eyes of 30 healthy participants served as control group. All eyes were scanned with HRT3 in vivo corneal confocal microscopy. Images of sub-basal nerve plexus were quantified including nerve fiber length (NFL), nerve fiber density (NFD), nerve fiber branch density (NFB), and nerve tortuosity (NT). The correlations of corneal nerve fiber with age, duration of diabetes and glycated hemoglobin (HbA1c) were analyzed using Spearman correlation analysis. Results NFL, NFD and NFB were found to be significantly lower in diabetic patients (F=147.315, 142.586, 65.898;P=0.000, 0.000, 0.000), NT was significantly greater in diabetic patients (F=39.431,P=0.000), when compared to control group. In diabetic patients, NFL, NFD and NFB were gradually reduced with DR severity, NT was gradually increased with DR severity. While the difference of NFL, NFD, NFB, NT was not statistically significant between sNPDR and PDR subgroups (P＞0.05), but was statistically significant between other subgroups (P＜0.05). Spearman correlation analysis results showed that age (r=－0.071, －0.080, 0.001, 0.100;P=0.391, 0.328, 0.991, 0.224) and HbA1c (r=－0.109, －0.115, －0.126, 0.025;P=0.238, 0.211, 0.169, 0.781) had no correlation with NFL, NFD, NFB, NT. Duration of diabetes was negatively correlated with the NFL, NFD (r=－0.212, －0.264;P= 0.020, 0.004), positive correlated with NT (r=0.261,P=0.004), and had no correlation with NFB (r=－0.119,P=0.194). Conclusions Corneal nerve fiber loss and nerve tortuosity increased were found in patients with type 2 diabetes, and even without diabetic retinopathy. The progress of corneal neuropathy was correlated with the severity of DR, but it was not change significantly between sNPDR and PDR.
Objective To observe the expression of Nogo66 receptor （NgR）in ratsprime; retina during the postnatal development． Methods The expression of NgR in 48 rats were observed by immunofluorescence histochemistry and laserconfocal microscopy 0, 3, 7, 14, 21, 35, 49, 63 days after birth, with 6 rats in each group, respectively． Results The expression of NgR is positive in the retina in the whole duration of growth, and the fluorescence pigmentation was located around the ganglion cell nuclaear. Conclusion The positive expression of NgR suggests that the interaction of NgR and CNS myelin inhibitors not only inhibit neuronal plasticity but also promote it, which could regulate neuronal plasticity.