Objective To explore the correlation between retinal extracellular edema and vitreous contraction in rabbits. Methods Seventeen pigmented rabbit models with retinal vein occlusion (RVO)was set up by laser photocoagulation. Retinal vascularity area was pathologically examined 1 month later.The vitreous gellength under the gravity condition and the percentage of its weight in the rabbits with extraeellular edema was observed. The mechanisms were investigated by Western immunoblotting of type II collagen.Results Extracellular edema was found in 13 experimental eyes 1 month after the formation of RVO (76.5~) with contracted vitreous gel and released watery liquid, and the a component of type II collagen was cross-linked together to form high-molecular-weight components of 1] and 7, which weakened the stability of collagen net structure.Conclusions Vitreous contraction and retinal extracellular edemawere correlated. The main reason may be the cross-links of vitreous collagen that damages the stability of collagen structure. (Chin J Ocul Fundus Dis，2004，20：2-32)
The prevalence of diabetes mellitus in adults of China has reached 12.8%. Diabetic retinopathy (DR) accounts for approximately 1/4-1/3 of the diabetic population. Several millions of people are estimated suffering the advanced stage of DR, including severe non-proliferative DR (NPDR), proliferative DR (PDR) and diabetic macular edema (DME), which seriously threat to the patients’ vision. On the basis of systematic prevention and control of diabetes and its complications, prevention of the moderate and high-risk NPDR from progressing to the advanced stage is the final efforts to avoid diabetic blindness. The implementation of the DR severity scale is helpful to assess the severity, risk factors for its progression, treatment efficacy and prognosis. In the eyes with vision-threatening DR, early application of biotherapy of anti-vascular endothelial growth factor can improve DR with regression of retinal neovascularization, but whether it is possible to induce capillary re-canalization in the non-perfusion area needs more investigation. Laser photocoagulation remains the mainstay treatment for non-center-involved DME and PDR.
Macular edema is a common cause of visual loss in patients with retinal vascular diseases represented by diabetic retinopathy and retinal vein occlusion. Laser photocoagulation has been the main treatment for this kind of diseases for decades. With the advent of antagonist of vascular endothelial growth factor and dexamethasone implant, diabetic macular edema and macular edema secondary to retinal vein occlusion have been well controlled; the use of laser therapy is decreasing. However, considering possible risks and complications, lack of extended inspection of efficacy and safety of intravitreal pharmacotherapy, laser therapy cannot be replaced by now. Therefore, the efficacy and safety of laser therapy will improve by sober realization of role of photocoagulation and proper selection of treatment indication.
In recent years, the subthreshold micropulse laser is a kind of laser mode which is characterized by long intermittence. It achieves effective therapeutic effect while minimizes the damage to tissues. At present, it has been used to treat diabetic macular edema. Early studies suggested that the laser selectively acts on retinal pigment epithelial cells to reduce macular edema by regulating the expression of inflammatory biomarkers, growth factors, heat shock proteins and other substances. In recent years, with the development of research, more and more emphasis has been placed on the role of retinal glial cells. Müller cells are also considered as one of the target cells affected by micropulse laser, but there is no evidence of direct or indirect effects of micropulse laser on Müller cells. In the near future, it is expected that we will have more clinical evidence to confirm the target cells of the micropulse laser, which may be further confirmed by in vitro experiments through Müller cells or Müller cells co-cultured with retina pigment epithelium cells, so as to make a more detailed statement on the mechanism of it.
ObjectiveTo observe the characteristics of choroidal thickness in patients with macular edema secondary to superior temporal branch retinal vein occlusion (BRVO-ME). MethodsA retrospective control study. From November 2020 to September 2021, 30 patients (30 eyes) with BRVO-ME (BRVO-ME group) were diagnosed by ophthalmology examination in Department of Ophthalmology, The Affiliated Hospital of Chengde Medical College and 14 healthy volunteers (28 eyes) were enrolled in the study. The choroidal thickness of macular area was measured by enhanced deep imaging technique of frequency domain optical coherence tomography. According to the subdivision of the diabetic retinopathy treatment group, the choroid within the 6 mm of the macular fovea was divided into three concentric circles with the macular fovea as the center, namely, the central area with the diameter of 1 mm, the inner ring of 1-3 mm and the outer ring of 3-6 mm. The inner ring area and the outer ring area are divided into upper, lower, nasal and temporal sides, respectively, which are denoted as S3, I3, N3, T3 and S6, I6, N6, T6, totaling 9 areas. To observe the distribution characteristics of choroidal thickness in different regions of two groups of eyes. The choroidal thickness of different macular regions was compared by independent sample t-test. ResultsThe choroidal thicknesses in the central area, S3, T3, I3, N3, S6, T6, I6, and N6 of the eyes in the control group and BRVO-ME group were 214.11±56.04, 207.89±57.92, 214.07±54.82, 207.14±61.54, 180.18±53.53, 204.25±59.60, 193.93±51.50, 190.54±51.21, 139.82±39.84 μm and 258.00±71.14, 256.43±68.70, 252.07±72.97, 244.37±68.49, 243.10±70.93, 247.20±68.36, 221.00±61.28, 223.77±58.64, 183.20±60.15 μm. In both groups, the choroidal thickness was the thickest in the central area, gradually thinning to the nasal side and temporal side, and the nasal choroidal thickness was thinner than other regions, and N6 area was the thinnest. Compared with the control group, the choroidal thickness of central area, S3, T3, I3, N3, S6, I6 and N6 in BRVO-ME group were significantly thicker (t=－2.899, －2.229, －2.172,－3.250, －2.543, －2.292, －3.214; P＜0.05), there was no significant difference in T6 area (t=－1.814, P=0.075). ConclusionThe choroidal thickness of macular area in patients with BRVO-ME is thicker than that in normal subjects.
Objective To investigate the effects of Atorvastatin calcium on the incidence of macular edema after phacoemulsification in diabetic patients. Methods Forty two eyes of 42 cataract patients with diabetes and hypercholesterolemia who underwent phacoemulsification surgery were divided into interventional group (23 patients) and non-interventional group (19 patients) by random number table methods. The blood glucose and pressure of patients in two groups was controlled strictly before and after surgery. 10 mg Atorvastatin calcium per day was delivered one day after cataract surgery for the patients of interventional group and used for 24 weeks. No lipid-lowing agent was provided to the patients of non-interventional group. The main outcome measures included the best corrected visual acuity (BCVA), central retina thickness (CRT), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). No significant difference was shown in the BCVA, CRT, TC, LDL-C and HDL-C in two groups before phacoemulsification surgery (t=1.251, 1.257, 1.031, 1.042, 1.461; P > 0.05). At the end of the 24 weeks after surgery, the efficacy evaluation and comparative analysis were performed. The analysis included the BCVA, the incidence of macular edema, CRT, TC, LDL-C and HDL-C. Results The BCVA was no significantly different between two groups one day after surgery (t=1.523，P > 0.05). But 4, 12, 24 weeks after phacoemulsification surgery, the BCVA in interventional group was better than that in non-interventional group(t=3.920, 3.012, 7.025; P < 0.05). 24 weeks after the operation, macular edema was occurred in 2 eyes (8.69%) in interventional group and 4 eyes (21.05%) in non-interventional group. Significance difference was found between two groups (χ2=4.896，P < 0.05). There was no significance different of the CRT between two groups one day after operation (t=1.501，P > 0.05). Whereas, the significance difference of the CRT was occurred in two groups 4, 12, 24 weeks after surgery(t=4.673, 7.583, 9.035; P < 0.05). Comparing with that in non-interventional group, the level of TC (t=7.043, 7.930, 8.611)and LDL-C (t=9.374, 9.554, 10.856) in interventional group was significantly decreased 4 to 24 weeks after operation (P < 0.05). But no significance different of HDL-C was shown in two groups 4, 12 and 24 weeks after surgery (t=1.057, 1.127, 1.295; P > 0.05). Conclusion The treatment of Atorvastatin calcium effectively reduced the incidence rate of macular edema in hypercholesterolemia patients with good glycemic and hypertension control after phacoemulsification surgery.
Objective To observe and analyze the risk factors of secondary intraocular hypertension in diabetic macular edema (DME) patients after treatment with dexamethasone vitreous cavity implant (DEX). MethodsA retrospective observational study. A total of 352 patients with type 2 diabetes mellitus (T2DM) secondary macular edema diagnosed by ophthalmic examination and treated with DEX in Department of Ophthalmology of Harbin 242 Hospital from January 2016 to March 2022 were included in the study. Among them, 221 were males and 131 were females, with the mean age of (55.56±8.09) years. There were 194 patients with disseminated macular edema, 158 patients with cystoid macular edema. All patients underwent vitreous cavity implantation of DEX. Intraocular pressure (IOP) was measured once a month for 3 months after treatment, with IOP over than 25 mm Hg (1 mm Hg=0.133 kPa) or higher than 10 mm Hg from baseline as secondary intraocular hypertension. The relevant clinical data were collected, and the risk factors of secondary intraocular hypertension in DME patients after DEX treatment were analyzed by binary logistic regression. ResultsAmong 352 patients, 116 patients (32.95%, 116/352) were in the intraocular hypertension. Among them, 29 patients (25.00%, 29/116), 69 patients (59.48%, 69/116) and 18 patients (15.52%, 18/116) occurred intraocular hypertension at 1, 2 and 3 months after treatment, respectively. Compared with the normal IOP group, the IOP in the intraocular hypertension group increased significantly at 1, 2 and 3 months after treatment, with statistical significance (t=10.771, 21.116, 13.761; P＜0.001). Compared with normal IOP group, the patients in the intraocular hypertension group had younger age (t=6.967), longer duration of diabetes (t=5.950), longer axial length (AL) (t=14.989), higher proportion of DME grade 3 (Z=6.284), higher proportion of DEX implantation in pars plana (χ2=23.275), and higher HbA1c level (t=10.764), the differences were statistically significant (P＜0.05). Logistic regression analysis showed that longer AL [odds ratio (OR)=1.428, 95% confidence interval (CI) 1.054-1.934], DEX implantation in pars plana (OR=1.358, 95%CI 1.063-1.735), and higher HbA1c (OR=1.702, 95%CI 1.225-2.366) were the risk factors for secondary intraocular hypertension in DME patients after DEX treatment (P＜0.05), older age was a protective factor (OR=0.548, 95%CI 0.380-0.789, P＜0.05). ConclusionsLong AL, DEX implantation in pars plana and high HbA1c are the risk factors for secondary intraocular hypertension after DEX treatment in DME patients, older age is a protective factor.
Diabetic macular edema is the leading cause of central vision loss and even blindness in diabetic retinopathy. Compared to FFA, OCT can obtain the high-resolution 3D image quickly, easily to reflect the details of the tissue and realize the quantitative measurement. As a novel technology, OCT angiography (OCTA) can display microvascular structure from different layers of retina and choroid, having its advantage of quantifying the vessel density and the lesion area. By detecting fundus morphology, quantifying and quantitating the retinal vessels and vessel density, the combination of OCT and OCTA could play a guiding role in diagnosis, classification, treatment and prognosis of diabetic macular edema.