Objective To observe the relationship between the size of idiopathic macular hole (IMH) and the healing types of postoperative photoreceptor layer after vitrectomy. Methods This prospective uncontrolled study included 33 eyes of 31 consecutive patients who underwent vitrectomy for IMH. There were 9 males (9 eyes) and 22 females (22 eyes), with the mean age of (58.16±9.10) years. The mean duration of symptoms was (4.97±5.97) months. The best corrected visual acuity (BCVA) and optical coherence tomography (OCT) were measured for all patients. BCVA was measured with international standard visual acuity chart and then converted to logarithm of the minimum angle of resolution (logMAR). The mean logMAR BCVA was 1.07± 0.38. The mean intraocular pressure was (14.05±0.54) mmHg (1 mmHg=0.133 kPa). The minimum size of the macular hole (MIN), the base diameter of the macular hole (BASE), the average width of the macular hole (AWMH) and the average height of the macular hole (AHMH) were (465.19±232.84), (943.63±389.26), (704.72±292.64), (443.84±72.47) μm, respectively. According to the MIN value, the hole size were divided into small, medium and large group which had 9 eyes, 15 eyes, 9 eyes, respectively. According to the postoperative OCT characteristics, the healing types of the photoreceptor layer were divided into 0 - Ⅳ types. All patients underwent pars plana vitrectomy (25G or 27G standard three-incision) with internal limiting membrane peeling with tamponade agents. The mean follow-up was (326.42±157.17) days. The first postoperative OCT characteristics were defined as the early period. The therapy results were evaluated according to the last follow-up time point. BCVA and intraocular pressure before and after operation were compared by paired t test. The postoperative BCVA were compared with preoperative BCVA, MIN, AWMH, AHMH and follow-up using Pearson correlation analysis. Results At the last follow-up, the LogMAR BCVA was 1.52 - 1.40 in 3 eyes, 1.30 - 0.52 in 22 eyes and 0.40 - −0.07 in 8 eyes. Compared with preoperative that, the difference was statistically significant (t=−6.023, P＜0.001). The photoreceptor healing was type 0 in 10 eyes (30.3%), type Ⅰ in 4 eyes (12.1%), typeⅡ in 10 eyes (30.3%), type Ⅲ in 9 eyes (27.3%) at the early postoperative period. The photoreceptor healing was type 0 in 5 eyes (15.2%), type Ⅰ in 5 eyes (15.2%), type Ⅲ in 12 eyes (36.4 %), type Ⅳ in 11 eyes (33.3%) at the last follow-up. The preoperative size of IMH was negatively correlated to the photoreceptor healing types at early postoperative period (r=−0.590, P＜0.01) and the last follow-up (r=−0.768, P＜0.01), respectively. The correlation analysis showed that the postoperative BCVA associated with the preoperative BCVA, the stage of the macular hole, the size of the macular hole, MIN, BASE, AWMH, AHMH, the healing types of photoreceptor layer of the early and the last follow-up after surgery (r=0.500, 0.370, 0.470, 0.435, 0.533、0.505, 0.462, −0.442, −0.656, P＜0.05). There was no correlation between age, visual decreasing times and follow-up times (r=0.285, 0.234, −0.310, P＞0.05). Conclusion The preoperative sizes of IMH were associated with the postoperative healing types of photoreceptor layer.
Objective To investigate the mechanism of the toxic effect of N methyl N-nitrosourea (MNU) on photoreceptor cell apoptosis of rat’s retina. Methods Thirty 50-day-old female Sprague-Dawley ( SD ) rats were intraperitoneally injected with MNU (60 mg/kg) and were put to death by dislocation of cervical vertebra 12, 24, 48, and 72 hours and 7 days after the injection, respectively. The photoreceptor cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope. The expression of proliferating cell nuclear antigen (PCNA), vimentin and glial fibrillary acidic protein (GFAP) was detected at different time after injection by immunohistochemical methods. Results The apoptotic index of the retina in the posterior pole was (33. 6±2. 3), (46. 5±5. 7), (20. 1±5. 3), (8. 2±3. 6) and (2. 5±1. 3~//oo at the 12th,24th, 48 th, and 72nd hour and on the 7th day, respectively, after injection. Karyopyknosis was found in most photoreeeptor cells 24 hours after injection. The expression of PCNA was found in internal granularlayer and between internal granular layer and choroid 24 hours after injection, reached the peak after 72 hours, and reduced obviously after 7 days. The positive expression of GFAP and vimentin was found in internal and external granular layer 24 hours after injection, reached the peak after 72 hours, and reducedobviously after 7 days.Conclusion MNU may selectively lead the photoreceptor cell apoptosis and proliferation of Mvller cells. (Chin J Ocul Fundus Dis，2004，20：33-36)
Objective To demonstrate if apoptosis is one of the mechanisms of siderotic retinopathy. Methods Autoclaved iron particles were implanted in the vitreous cavities of 32 eyes of SD rats.Glass chips were implanted in 10 control eyes.The experimental eyes were enucleated at various time intervals from days 1 to 15.Retinal degeneration was examined using the TdT-mediated,dUTP-biotin nickend labeling(TUNEL)method.Electrophoresis on agarose gel was used to detect internucleosomal DNA fragmentation.Results TUNEL-positive nuclei were observed only in the outer nuclear layer beginning on day 2.The nuclei spread throughout the outer nuclear layer by the end of day 3.No TUNEL-positive nuclei were observed in other layers throughout the experimental perios.Analysis of DNA,extracted from the retinas by electrophoresis on agarose gel,revealed a typical ladder pattern of internucleosoma DNA cleavage in the experimental eyes.ConclusionApoptosis of photoreceptors occurs at the early phase of iron-induced retinopathy in the rats.
Objective To investigate the correlation of ascorbic acid distribution and retinal susceptibility to iron toxicity of the retina.Methods Autoclaved iron particles of 5 mg and 15 mg were implanted into the vitreous cavities of 32 Spragu-Dawley (SD) rats and 9 rabbits, respectively. The retinal sections of rats and rabbits were examined after hemotoxylin-eosin (HE) staining. Apoptos is of rabbits′retinal neurons was investigated by TdT-mediated dUTP-biotin nick-end labeling (TUNEL). Chinoy′s method was used to observe the distribution of as corbic acid in the retinae of the 2 kinds of animals.Results In rats, histological and structural densification was observed only in the photoreceptor cells after implantation of the iron particles. In rabbits, however, histological and structural destruction as well as TUNEL-positive nuclei were observed in all neuronal layers of the retina 3 days after the implantation of the iron particles. Silver granules reduced by ascorbic acid from silver nitrate were observed only in the outer nuclear layer in normal rats retinae, while they were observed evenly throu ghout all layers of rabbits′retinae. Conclusions The suscept ibility of retina to iron toxicity is correlated to the distribution of ascorbic acid in retina. (Chin J Ocul Fundus Dis，2003，19：269-332)
Objective To investigate the feasibility of gene transfection into retinal pigment epithelial (RPE) cells and photoreceptors (PRs) in vivo electroporation. Methods A total of 147 Sprague-Dawley (SD) rats were divided into 5, 10, 15, 20, 25, 30 and 35 V group according to different voltage. The right eyes of rats underwent the injection of eukaryotic expressive plasmid of enhanced green fluorescent protein (EGFP) pEGFP-N1 into subretinal space as experimental eyes; the left eyes were injected with TE buffer as control eyes. Each group was divided into RPE and RP subgroups according to different transfection direction. There were same parameters of 99 ms pulse width, 0.5 s pulse interval and 5 consecutive pulses except different voltage in groups. With a negative charge in the electric field was transfected into RPE cell layer, reverse electrode set to be transfected into PR cell layer. Retina mounts were made on seven days after transfection and the fluorescence of EGFP was photographed by fluorescent microscope. The expression of EGFP mRNA and protein were detected by reverse transcription polymerase chain reaction technique (RT-PCR) and Western blot.Results On seven days after transfection, in RPE subgroups, there were no specific fluorescence expressions in RPE cell layer and retina mounts of control eyes, while there were fluorescence expressions in experimental eyes. Western blot showed that the grayscale ratio of EGFP protein and beta;actin protein bands rose with the increased voltage. RT-PCR showed that each group produced positive amplification bands, and the relative ratio of gray level of EGFP mRNA and GADPH mRNA amplified bands gradually increased with the increased voltage.Conclusion Electroporation is an effective method for gene delivery into RPE cells in vivo.
Objective To observe the changes of electrophysio logical results in rabbits with normal and injured photoreceptor due to subretinal implantation of chip. Methods Photoreceptor damage was induced by injection with NaIO3 solution in 22 out of 30 rabbits. A chip with the diameter of 3 mm made by the array composed of 90 microelectrodes photodiode and conjoint electrode was implanted into subretinal space or choroid of the right eyes of 22 rabbits with photoreceptor and 4 normal rabbits, and the left eyes were the control. The examinations of local flash-visual evoked potential (F-VEP), local flash-electroretinogram (F-ERG), full-field F-ERG and full-filed F-VEP were measured respectively.Another 4 rabbits underwent biocular extirpation for path ological examination . Results In 22 rabbits with photo-receptor damage, the amplitude of the main wave of local ERG was obviously higher in 11 eyes with chips than that in the control ones, and was also higher in 2 eyes with chips of the 4 mormal rabbits than that in the control eyes. No wave was found in an eye with retinal hole on the surface of the chip. The repeataility of main amplitude of local-VEP and full-field F-VEP is not satisfactory; no significant changes were observed between chip-implanted eyes and the control eyes examined by full-filed F-ERG. Conclusion The implanted chip may stimulate local retina and induce electrical activities after stimulated by light. (Chin J Ocul Fundus DIs, 2006, 22: 324-327)
PURPOSE:Investigating on histopathologic changes of the photoreceptors in retinitis pigmentosa. METHODS:Observation of the photoreceptors of retinitis pigmentosa in 11 eyes among 9 cases using light and electron microscope. RESULTS: The pathologic changes of the photoreceptors were found to be mostly marded at the equatorial area and less at the periphery,posterior pole and macular region of the retina. In relatively early cases,degeneration and shortening of outer segments,reduction or loss of connecting cilia,stubby inner segments and swollen mitochondria Were the predominant findings. In advanced cases,the inner and outer segments and connecting cilia were diminished with reduction of nuclei in number and disarangement,cellular degeneration and disorganization. The outer limiting membrane adhered to RPE or Bruch membrane. The spaces left over by the above pathologic changes were replaced by the displaced Muuml;ller cells and their hypertrophic processes. Also there were degeneration of the RPE cells,and some of them might migrate into the retina. CONCLUSION:Obvious invasions of pathologic processes in photoreceptors of the retina did present in patients with retinitis pigmentosa. （Chin J Ocul Fundus Dis,1996,12:160-162）
Objective To observe the distribution of human photoreceptor cells at the posterior pole, detect the change of density of the cells affected by eccentricity, and analyze the relationship between the density distribution and the visual sensitivity. Methods Twenty human eye cups with the cornea removed were fixed in 4% polyformaldehyde for 1-4 weeks, and the retinal mounts were observed by differential interference contrast microscope to reveal the retinal cellular configuration and density. The inner segments of photoreceptor cells were first observed from the center to the temporal peripheral part of the retinal mounts. Results The highest density of visual cone cells was at the central fovea (134 000-267 000/mm2, mean 198 090/mm2; CV value:18.2%). The density and individual variation decreased rapidly in the peripheral area. The high density area of rod cells was at the 4 mm of the eccentricity, with the highest value of 72 610-182 350/mm2 and with the high density between 3 and 5 mm. Conclusions The inner segment of photoreceptor cells was monolayer, which may tell the cellular absolute value. The high density of retinal cone cells at the central fovea provide the basis of sensitive central visual acuity, which relates to the individual variation and development. The rod cells have the peak density at the eccentricity with 4 mm, and this area has the greatest sensitivity of dim vision.
Objective To observe the effects of local macular foveal photoreceptor defects on visual acuity.Methods Thirty-one patients (31 eyes) with photoreceptor defect in macular fovea (case group) diagnosed by spectral domain optical coherence tomography (SD-OCT) and 30 patients (30 eyes) age- and diopter- matched normal subjects (control group) were enrolled in this study. There were 22 eyes with full photoreceptor defects and 9 eyes with outer segment defects in case group. All subjects were examined for best corrected visual acuity (BCVA), slit-lamp microscopy, direct ophthalmoscope and SD-OCT. Independent sample t-test was used to compare central foveal thickness (CFT) between case group and control group. Difference of logMAR BCVA, CFT, maximum width and height of photoreceptor defects, defected area and residual retinal thickness in macular between patients with full photoreceptor defects and outer segment defects were also compared.Results The CFT of case group and control group were (225.32plusmn;19.70),(240.02plusmn;10.70) mu;m, the difference was not statistically significant (t=-1.96, P＞0.05). In full photoreceptor defects and outer segment defects patients, the mean logMAR BCVA were 0.22plusmn;0.31, 0.32plusmn;0.43; the mean CFT were (224.09plusmn;20.57), (228.33plusmn;18.17) mu;m; the maximum width of photoreceptor defects were (131.32plusmn;108.18), (143.22plusmn;66.93) mu;m; the mean defected area were (0.022plusmn;0.054), (0.019plusmn;0.019) mm2; the mean maximum height of photoreceptor defects were (77.41plusmn;6.62), (44.89plusmn;4.26) mu;m; the mean residual retinal thickness were (87.00plusmn;20.31), (128.33plusmn;23.54) mu;m respectively. There was no statistical significance between full photoreceptor defects and outer segment defects patients in the mean logMAR BCVA, CFT, maximum width of photoreceptor defects and defected area (t=-0.76, -0.538, -0.305, 0.166; P＞0.05), but there were significant difference in mean maximum width of photoreceptor defects and residual retinal thickness (t=12.72, -4.91;P＜0.05). Conclusions The local photoreceptor defects in macular fovea can lead to decrease of visual acuity. The wider the photoreceptor defects, the worse the visual acuity.
Objective To analyze the thickness of peripapillary retinal nerve fiber layer (pRNFL) and photoreceptor (PR) sublayer in Leber hereditary optic neuropathy (LHON) and G11778A mutation carriers. MethodsA cross sectional study. From September 2020 to October 2021, 68 LHON patients (136 eyes) (patient group) and 40 G11778A mutation carriers (80 eyes) of LHON patients' families (carrier group) were included in the study. All patients were found to have G11778A mutation by Genetic testing. Forty healthy volunteers with 80 eyes matched to the age and gender of the patient group were recruited as a normal control group. All eyes were examined by optical coherence tomography (OCT). The pRNFL thickness was automatically measured by the built-in software of the OCT device. The total retinal thickness (MT) and the thickness of the outer bundle layer (OPL), outer nuclear layer (ONL), external limiting membrane to retinal pigment epithelium (ELM-RPE) in macular OCT images were measured by Image J software. Linear mixed model was used to analyze and compare the thickness of pRNFL, macular fovea and four layers above the nasal and temporal paracentral retina in patients, carriers and normal controls. The correlation between pRNFL and macular retinal sublayer thickness and the course of disease was also analyzed. ResultsThe thickness of the upper and lower pRNFL, temporal pRNFL and average pRNFL of the patients were smaller than those of the carriers and the normal control group (P＜0.01), and the nasal pRNFL thickness of the patients was smaller than that of the carriers (P＜0.01). Fovea: compared with the normal control group, the thickness of MT and ONT in the patient group was decreased, ONL thickness decreased in carrier group, with the significant different (P＜0.05). Parafovea: compared with normal control group, the thickness of MT and temporal ONL decreased and temporal OPL increased in the patients group, with the significant different (P＜0.05). In the carrier group, the thickness of MT and temporal, nasal ONL decreased, and the thickness of nasal OPL increased, with the significant different (P＜0.05). Compared with the carrier group, the MT thickness of the patient group was decreased, and the nasal ONL and nasal ELM-RPE thickness were increased, with the significant different (P＜0.05). Correlation analysis results showed that the thinning of pRNFL in the superior, nasal, temporal and average (r=－0.22, －0.21, －0.25, －0.22), and the thickening of ELM-RPE in foveo-temporal (r=0.19) were correlated with the course of disease (P＜0.05). ConclusionsThe pRNFL of LHON patients with G11778A mutation becomes thinner and is related to the course of the disease. There were significant differences in the thickness of MT and PR sublayers between patients and carriers compared to the normal control group.