The pathogensis of choroidal vascular changes in traumatic rtinopethy remains uncertain.We performed scanning electron micrmcopie (SEM) observation of methyl methalerylare vascular corrosion casts in a rabbi model with severe retinal contusion. Areas of filling defects in corrosion casts of the choriocapillaries, correspending to the areas of impact retinal lesions were noted in the traumatized eyes one to 28 days after trauma.No neovascularization was found in the eyes 56 days after trauma. The results confirm that obstruction and disappearance of involved choriocapillaries are the main changes of choroidal vasculatrue in severe blunt tram. The changes may be associated with continuous necrosis, of the photoreceptors 4 weeks after injury. （Chin J Ocul Fundus Dis,1993,9:5-7）
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 effect of scanning laser ophthalmoscope (SLO) measuring macular light sensibility on evaluating the visual function in idiopathic epiretinal membrane (IERM), and analyze the relationship among the macular light sensibility, central visual acuity, and the thickness of fovea. Methods Procedure of microperimetry of SLO was performed on 44 patients (55 eyes) with IERM diagnosed by indirect and direct ophthalmoscope and optical coherence tomography (OCT). The light sensibility at 10deg;macular central area was measured. The results were compared with 31 healthy control eyes which underwent the same examinations simutaneously. The correlation among the macular light sensibility, the thickness of fovea measured by OCT, and the results of logarithm visual acuity was anaylzed. Results Compared with the control eyes, macular light sensibility decreased in IERM eyes significantly (F=47.265, Plt;0.01), which had the positive correlation with the decrease of visual acuity (r=0.687, P=0.000) and negative correlation with the retinal thickness of macular fovea (r=-0.532,P=0.003). The mean macular light sensitivity in patients with metamorphopsia decreased obviously compared with which in patients without (t=7.039, P=0.000). The mean macular light sensitivity in patients with prolifertive IERM decreased compared with which in patients with dropsical IERM without statistical difference (t=-1.706, P=0.094). Conclusion Microperimetry of SLO may sensitively reflect the macular visual function of eyes with IERM and quantificationally evaluate the changes of macular light sensibility. The changes of macular light sensitivity correlates with the central visual acuity and retinal thickness of macular fovea. (Chin J Ocul Fundus Dis, 2006, 22: 100-102)
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)
Diabetic retinopathy (DR) is one of the most common causes of visual impairment and blindness in diabetic patients. It is particularly important to set up simpler, safer, non-invasive and highly effective methods for diagnosis as well as monitoring DR. A variety of new fundus imaging techniques show great advantages in early diagnosis, treatment and monitoring of DR in recent years. The main characteristics of wide-field scanning laser imaging system is achieving a large range of retinal image in a single photograph and without mydriasis. It provides several options for color images, FFA and FAF, which satisfy to detect the retina, choroid and vascular structure. Multi spectral fundus imaging system is suitable for DR screening, because it is able to recognize the typical characteristics of DR, such as microaneurysms, hemorrhage and exudation, and is non-invasive and convenient. OCT angiography is a quantitative examination that provides foveal avascular zone area, macular blood flow density, which provides strong evidence for DR diagnosis. The improvement of these new techniques will help us to build up a personalized evaluation system of DR.
Purpose To verify the effectiveness of combined B-scan ultrasonoscopy and ultrasound biomicroscopy(UBM)imagings in diagnosis of retinal detachments. Methods To contrast the manifestations in vitrectomy operations with the findings of preoperative combined B-scan ultrasonic and UBM examinations in 25 eyes of 25 cases in which 18 eyes with rhegmatogenous retinal detachment and 7 eyes with traumatic retinal detachment were included. Results B-scan ultrasonic imagings were divided into four types: type C,type V,type upsilon; and type gamma;,which included 6 eyes,2 eyes,4 eyes and 11 eyes respectively,and from type C to type gamma;,the retinal detachments manifested themselves from simple posterior segment proliferative vitreoretinopathy(PVR)to both anterior and posterior PVR.The imagings of UBM were divided into 3 types:shallow retinal detachment,retinal circumferential contraction and retinal anterior displacement,which reflected the degree of anterior PVR from lightness to severeness. Conclusions The technique of combined B-scan ultrasonoscopy and UBM can be used to access the severity of the retinal detachments,hence would be beneficial in diagnosing anterior and posterior PVR,designing the surgical precedures and assessing the prognosis. (Chin J Ocul Fundus Dis,1998,14:16-20)
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 verify the applicable significance of confocal scanning laser retinal tomography in agerelated macular degeneration (AMD). Methods Heidelberg confocal scanning laser tomography was used to measure 75 eyes of 59 patients with AMD, including 25 eyes of 20 patients with exudative AMD, 25 eyes of 16 patients with atrophic AMD, and 25 eyes of 23 patients with macular drusen. The differences of the width, volume and maximum height of Z profile signal of macula were analyzed. Results Z profile signal width in macular tomography of exudative AMD was wider than that of macular drusen; maximum height and volume in macular tomography of exudative AMD were larger than that of macular drusen (P＜0.01); Z profile signal width, maximum height，and volume in macular tomography of atrophic AMD were wider and larger than that of macular drusen (P＜0.05). Macular volume of exudative AMD was obviously larger than that of atrophic AMD (P＜0.01). Conclusion Confocal scanning laser tomography may be one of the useful methods for objective evaluation of morphologic change for the development of AMD. (Chin J Ocul Fundus Dis, 2002, 18: 262-265)