Objective：To observe the protective effect of ginkgo bilo ba extrac t (EGb 761), a free radical scavenger, on the photoreceptor cells after lighti nduced retinal damage. Methods：Seventytwo female SpragueDa wley (SD) rats we re randomly divided into 4 groups: normal control group, lightinduced retinal da m age model group, model+physiological saline group, and model+EGb 761 group, with 18 rats in each group. All of the rats except the ones in the control group were exposed to white light at (2740plusmn;120) lx for 6 hours after the dark adap tation for 24 hours to set up the lightinduced retinal damage model. Rats in m o del + physiological saline group and model+EGb 761 group were intraperitoneall y injected daily with physiological saline and 0.35% EGb 761 (100 mg/kg), respec tively 7 days before and 14 days after the light exposure. Apoptosis of photorec eptor cells was detected 4 days after light exposure; 7 and 14 days after light exposure, histopathological examination was performed and the layer number of ou ter nuclear layers (ONL) on the superior and inferior retina was counted. Results：Four days after light exposure, the apoptosis of photorecep tor cells was fou nd on ONL in model, model+ physiological saline and model+EGb 761 group, and w as obviously less in model + EGb 761 group than in model and model+physiologic al saline group. Seven days after light exposure, the layers of ONL on the super ior retina were 3 to 4 in model and model+physiological saline group, and 7 to 8 in model+EGb 761 group; the mean of the layer number of ONL in model+EGb 761 group (6.92plusmn;0.82) was less than that in normal control group (8.40plusmn;0.95) (t=-1.416, P＜0.05), but significantly more than that in model (5.96 plusmn;1.36 ) and model+physiological saline group (5.90plusmn;1.40）（t=1.024, 1.084; P＜0.05). Fourteen days after light exposure, the layers of ONL on the superior retina were 0 to 1 in model and model+physiological saline group, and 3 to 4 i n model+EGb 761 group. The mean of the layer number of ONL in model+EGb 761 group (5.5 2plusmn;1.06) was significantly more than that in model (3.44plusmn;2.15) and model + physiological saline group (3.37plusmn;1.91) (t=2.082, 2.146, P＜0.05). Conclusion：EGb 761 can partially inhibit the apoptosis of pho toreceptor cells, thus exert protective effect on photoreceptor cells.
Objective To observe the visual field loss after 577 nm krypton pan-retinal photocoagulation (PRP) in the treatment of diabetic retinopathy (DR). Methods A prospective clinical studies. Forty-six eyes of 26 patients with proliferative DR (PDR) and severe non-proliferative DR (NPDR) diagnosed by clinical examination from No. 306 Hospital of PLA during January 2014 and December 2015 were included in this study. Among them, 21 eyes of NPDR and 20 eyes of PDR; 13 eyes with diabetic macular edema (DME) (DME group) and 28 eyes without DME (non-DME group). All eyes underwent best corrected visual acuity (BCVA), fundus color photography, fundus fluorescein angiography (FFA) and optical coherence tomography (SD-OCT) examinations. The visual field index (VFI) and visual field mean defect (MD) values were recorded by Humphrey-7401 automatic visual field examination (center 30° visual field). The BCVA of DR eyes was 0.81±0.28; the VFI and MD values were (89.8±8.4)% and −7.5±3.85 dB, respectively. The BCVA of the eyes in the without DME group and DME group were 0.92±0.20 and 0.57±0.27, the VFI were (90.86±7.86)% and (87.46±9.41)%, the MD values were −6.86±3.43 and 8.87±4.48 dB. PRP was performed on eyes using 577 nm krypton laser. The changes of VFI, MD and BCVA were observed at 1, 3, and 6 months after treatment. Results Compared with before treatment, the VFI of DR eyes decreased by 12.0%, 12.3% and 14.8% (t=7.423, 4.549, 4.79; P＜0.001); the MD values were increased by −4.55, −4.75, 6.07 dB (t=−8.221, −5.313, −5.383; P＜0.001) at 1, 3 and 6 months after treatment, the differences were statistically significant. There was no difference on VFI (t=1.090, −0.486; P＞0.05) and MD value (t=−0.560, −0.337; P＞0.05) at different time points after treatment. Compared with before treatment, the BCVA was significantly decreased in DR eyes at 1 month after treatment, the difference was statistically significant (t=2.871, P＜0.05). Before and after treatment, the BCVA of the DME group was lower than that of the non-DME group, the difference were statistically significant (t=4.560, 2.848, 3.608, 5.694; P＜0.001); but there was no differences on the VFI (t=1.209, 0.449, 0.922, 0.271; P＞0.05) and MD values (t=1.582, 0.776, 0.927, 1.098; P＞0.05) between the two groups. Conclusion The range of 30° visual field loss is about 12%-14.8% after 577 nm krypton laser PRP for DR. VFI and MD can quantitatively analyze the and extent of visual field loss after PRP treatment.
ObjectiveTo investigate the medium and long-term influence of silicon oil versus heavy silicone oil on rabbit retinas. Methods28 health standard rabbits were randomly divided into A, B and C groups, with 12, 12 and 4 rabbits respectively. All rabbits received routine vitrectomy and tamponade with silicone oil (group A), or heavy silicone oil (group B) or balanced salt solution (group C). After 4, 8, 12 and 24 weeks, the retinal b-wave amplitude was measured by ERG, posterior retinal thickness was measured by optical coherence tomography (OCT). Retinal ultrastructure and tissue morphology were observed by transmission electron microscopy and optical microscopy. ResultsCompare to group C, the b-wave amplitude decreased at 4 weeks after surgery, and decreased at 8 weeks after surgery for group B, and decreased at 8 weeks after surgery, and decreased at 24 weeks after surgery for group A. The decreases were greater in group B than group A at 8, 12, 24 weeks after surgery, the difference was statistically significant (P < 0.05). The posterior retinal thickness of group A and B was thinner than group C at 24 weeks after surgery (P < 0.05). The decreases were greater in group B than group A, the difference was statistically significant (P < 0.05). Transmission electron microscopy and optical microscopy revealed severe pathological changes of retinal ultrastructure and morphology in group A and B rabbit eyes, at 12 weeks and 8 weeks after surgery respectively. The changes were more severe in group B and group A, including edema and necrosis in cone/rod cells, in disk membranes, mitochondria, cytoplasm, nucleus and other organelles. The morphological changes were also more severe in group B and group A, including degenerations of ganglion cell layer, inner nuclear layer changes. Those changes became more severe when the tamponade time extended. ConclusionThe heavy silicone influence on visual function, ultrastructures, histomorphology of rabbit retinas is much worse than the silicon oil, and the effect is more significant with its time prolong.
Objective To observe visual field outcome and refractive status of patients with retinopathy of prematurity (ROP) treated by laser photocoagulation. Method The data of 39 ROP patients (73 eyes) who received laser photocoagulation were retrospectively analyzed and compared with 13 normal control subjects (25 eyes) whose age and sex were matched with ROP group. There were 24 males (45 eyes) and 15 females (28 eyes) in ROP group, with an average age of (7.0±1.28) years. The first laser treatment was carried out at postnatal age (PA) of (38.74±3.82) weeks, the birth weight (BW) of (1402.33±369.61) g and the number of laser burns was (517.86±277.40). The control group included 7 females (13 eyes) and 6 males (12 eyes), with an average age of (7.17±0.96) years. The age (t=0.691) and gender (χ2=1.425) were comparable between the two groups (P=0.491, 0.233). The data of patients and controls were retrospectively analyzed including best corrected visual acuity, refractive examination, automated perimetry test. The differences of the mean deviation (MD) of visual field and the spherical equivalent (SE) between these two groups were comparatively observed. ROP patients were divided into no VF loss group (MD≤2 dB) and VF loss group (MD＞2 dB), mild VF loss group (MD≤6 dB) and moderate VF loss group (MD＞6 dB) according to the results of automated perimetry test, the differences of gestational age (GA), PA, BW, number of laser burns and SE between these groups were comparatively observed. Results The MD in ROP group and control group were 4.87±5.12 dB and 1.27±3.34 dB, respectively; the difference between the two groups was statistically significant (t=–4.01,P＜0.001). The subgroup analysis showed that BW, number of laser burns, and SE were significantly different between no VF loss group and VF loss group (t=2.074, –1.996, –2.162;P=0.042, 0.026, 0.034); while the GA was not significantly different between these two groups (t=1.973,P=0.052). The difference of PA was not statistical significant different between mild VF loss group and moderate VF loss group (t=2.03,P=0.051) and SE was significantly different between the above two groups (t=3.283,P=0.002). For refractive outcomes, the BW and ROP stage correlated with SE significantly (r=–0.304, –0.387;P=0.015, 0.002). The mean BCVA in ROP group was 0.84±0.23, and 59 eyes (91.2%) with BCVA better than 0.5. Conclusion Laser treatment for ROP tends to have less effect on long term refractive status and VF loss, with good visual outcome.
The introduction of anti-vascular endothelial growth factor (VEGF) therapy represents a landmark in the management of wet age-related macular degeneration (AMD). However, as a new therapy, several problems such as durability of the therapeutic effects, medication side effects, and medication selection have emerged. We should make appoint of improving the therapeutic effect and safety by realizing the limitation of the therapy, monitoring the clinical potential adverse reactions of anti-VEGF agents, and recommending individualized treatment.
Objective To explore the connection between the melanin content of retinal pigment epithelial (RPE) cells and the function of photoreceptors, and the function of melanin on retinal light damage. Methods Agematched old dopachrome tautomerase knockout (DCT-/-) mice and wildtype mice were collected as the DCT-/- group and wildtype group, with 20 mice in each group. Baseline electroretinograms (ERG) in accordance with the international standards for the clinical electrophysiology were performed on all the mice, and the max ERG was recorded. Two mice were randomly selected in each group and were executed，and the removal eyeballs were as the control. The remaining 18 mice in each group were exposed to cold fluorescent light with the quantity of electricity of 20 W for 36 hours with a circle of 12 hours light12 hours dark12 hours light, which was repeated continuously for three times. The light intensity was (5000plusmn;356) lx. Six days after the light illumination, ERG were performed again and the results were recorded. Cervical dislocation methods were used to executed 2 mice which were chosen randomly in each group, and the eyeballs were removed. The tissue sections were observed under the optical and electron microscope.Results The results of ERG showed that the amplitude of a and b wave was lower in DCT-/- group than that in wildtype group before and after light injury （a wave before light injury: t=-7.13，Plt;0.01；b wave before light injury: t=-4.414，Plt;0.01；a wave after light injury: t=-10.162，Plt;0.01；b waveafter light injury: t=-6.772，Plt;0.01）. The decrease of amplitude of a and b wave was much obvious in DCT-/- group than that in wildtype group （a wave:t=4.975,Plt;0.01；b wave:t=2.908,Plt;0.01）. After the light injury, retinal edema and thinning were found in DCT-/- group which wasobvious than that in wildtype group; the photoreceptor layers and melanin were more seriously affected in DCT-/- group than that in wild-type group.Conclusions After the light illumination, the melanin of RPE cells reduces and the function of photoreceptors decreases, which suggests that melanin may play an protective role in the light injury.
Objective To investigate the effect of micropulse di ode laser treatment on the retina in Brown-Norway rats (BN Rats). Methods 130 eyes of BN rats received irradiance of different powers of micr opulse diode laser with 810nm wavelength through a contact lens. Fundus color photography and fundus fluorescein angiography (FFA) were performed on day 1, 3, 7, 14 and 28 days after treatment. Animals were sacrificed on 1, 3, 7, 14 and 28 days separately for historical study. The expression of heat shock protein-70 (HSP-70) in the retina was observed with immunohistochemistry. Cell apoptosis of retina tissue was examined by TdT mediated dUTP nick end labeling (TUNEL). Results (1) No change was found in no visible reaction laser spots by light microscope. High duty cycles with threshold and suprathreshold en ergies can produce severe damage even to the inner nuclear layer. (2) HSP-70 ex pression was markedly increased in the inner nuclear layer at 1d after micropulse diode laser. This increase in HSP-70 expression peaked at day 3 whereafter a decline near to normal at 2 weeks was detected. (3) Apoptosis was detected mainl y in retinal pigment epithelium, outer nuclear layer, inner nuclear layer and ev en choroid by TUNEL after micropulse diode laser treatment. The TUNEL-positive cells increased with the laser power. Maximum TUNEL-positive cells could be seen at day 3 after treatment. Conclusions The retinal injury has positive relationship with laser energy. The thermal damage is confined to the RPE and spare the neurosensory retina when using threshold power (50mW) with 50% duty-cycle and supra-threshold power with high duty-cycle (100mW，5%～15%). The hyper expression of HSP-70 and apoptosis mechanism may play an important role in the tissue repair process. (Chin J Ocul Fundus Dis,2008,24:122-126)
ObjectiveTo evaluate the safety to perform 23G vitrectomy with scleral incisions at 5.0 mm behind the limbus.MethodsThis is a prospective uncontrolled case study. The data of 140 consecutive primary 23G vitrectomy patients (145 eyes) were enrolled in this study. There were 56 males (59 eyes) and 84 females (86 eyes), with the mean age of (56.34±9.98) years and axial length of (23.99±2.57) mm. There were 139 phakic eye and 6 aphakic eyes. All the eyes received 23G pars plana vitrectomy with scleral incisions at 5.0 mm behind the limbus. To measure the normal Chinese adult parameters of anteroposterior axis of the eyeball, lens thickness and scleral distances from the limbus to the plane passing through the lens posterior apex, the head CT scans of 105 patients without eye diseases in our hospital were studied during the same period of time for these vitrectomy surgeries. Pearson correlation analysis was used to analyze the relationship between age, anteroposterior axis of eyeball, lens thickness and scleral distances from the limbus to the plane passing through the lens posterior apex.ResultsSurgical related complications included retinal tears close to the scleral incision sites (3/145 eyes, 2.1%) and lens injury (3/121 eyes, 2.5%). No other surgical complications occurred, such as retinal hemorrhage, supra-choroidal expulsive hemorrhage and iatrogenic retinal detachment. Based on CT images, the average scleral distance from limbus to the plane passing through the lens posterior apex, anteroposterior axis of eyeball and lens thickness was (6.72±0.81), (24.39±0.97), (4.22±0.47) mm, respectively. The results of Pearson correlation analysis showed that age and lens thickness had statistically significant correlation (r=0.328 9, P=0.000 6).ConclusionPrimary 23G pars plana vitrectomy with incisions at 5.0 mm posterior to the limbus is safe.
Objective To observe and analyze the causes and prognosis of postoperative vitreous hemorrhage (PVH) after vitrectomy for proliferative diabetic retinopathy (PDR). Methods A total of 160 PDR patients (171 eyes) were enrolled in this retrospective study. There were 85 males and 75 females. The patients aged from 33 to 73 years, with the mean age of (56.40±8.97) years. All the patients were performed 25G pars plana vitrectomy by the same doctor. Fibrovascular membrane peeling and panretinal photocoagulation were performed during the operation. Combined phacoemulsification was performed in one hundred and five patients. Vitreous tamponade was used at the end of surgery, including silicone oil (43 eyes), C3F8 (63 eyes), air or fluid (65 eyes). The follow-up ranged from 6 to 22 months, with the mean follow-up of (9.34±6.97) months. The features of PVH were observed. The difference of age, HbA1c, creatinine level, the severity of the fundus lesions, whether received treatment of anti-vascular endothelial growth factor (VEGF), whether received combined cataract phacoemulsification were analyzed to find out the cause and prognosis of PVH. Results The corrected vision of all the patients after the primary PPV at the latest follow up was finger counting/1 meter. PVH occurred in 15 eyes of 15 patients, the incidence was 8.77%. The PVH occurred 2 weeks to 6 months after surgery. There were significant difference in age (t=2.551), proportion with tractional retinal detachment (χ2=7.431), progressive fibrovascular proliferation (χ2=4.987) and using anti-VEGF (χ2=9.742) between the patients with and without PVH (P＜0.05). There was no significant difference in HbA1c (t=0.501), creatinine level (t=1.529), and the proportion of cataract phacoemulsification (χ2=0.452) between the patients with and without PVH (P＞0.05). During follow-up, neovascularization of iris (NVI) occurred in 1 eye and neovascular glaucoma (NVG) occurred in 4 eyes. Seven eyes underwent reoperation, 7 eyes were spontaneous recovered, 1 eye with NVG give up treatment. Fibrovascular membrane was the major cause of recurrent hemorrhage. At the end of follow-up, hemorrhage was absorbed in all the 14 eyes which were treated, 12 eyes had same visual acuity compared to that before postoperative hemorrhage, 2 eyes with NVG had decreased vision. There was significant difference in the corrected vision between the patients with and without NVI or NVG (P=0.022). Conclusions PVH after PPV for PDR is closely related to the severity of diabetic retinopathy, fibrovascular membrane is the major cause of recurrent hemorrhage. NVG is an important factor related to vision acuity prognosis.