ObjectiveTo observe the changes in the biomechanical properties of the cornea of diabetic retinopathy (DR), and analyze its relationship with the degree of DR. MethodsA retrospective study. From September 2020 to February 2021, 83 patients with type 2 diabetes (T2DM) combined with DR treated in the Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, 83 eyes (DR group), 30 patients with T2DM without DR recruited from the outpatient clinic 30 eyes (NDR group) and 30 eyes of non-diabetes patients (NDM group) were included in the study. All left eyes were chose as the study eye. Among the 83 eyes in the DR group, 39 eyes were non-proliferative DR (NPDR) and 44 eyes were proliferative DR (PDR). Based on this, they were divided into NPDR group and PDR group. There was no statistically significant difference in age (t=1.10) and sex ratio (χ2=0.46) among patients in the DR group, NDR group, and NDM group (P>0.05); body mass index (t=3.74), glycosylated hemoglobin (t=35.02) and the length of the eye axis (t=5.51), the difference was statistically significant (P<0.05). The eye response analyzer (ORA) was used to measure the corneal hysteresis (CH), corneal resistance factor (CRF), Goldman related intraocular pressure (IOPg), and corneal compensatory intraocular pressure (IOPcc). The corneal topography was used to measure the central corneal thickness (CCT) of the examined eye. The differences of CCT, IOPcc, IOPg, CH, CRF among multiple groups were compared by one-way analysis of variance. Multiple linear regression was used to analyze the relationship between CH, CRF and related influencing factors in DR patients. ResultsThere were statistically significant differences in CCT, IOPcc, IOPg, CH, and CRF among the eyes of the DR group, NDR group, and NDM group (F=3.71, 5.60, 9.72, 9.02, 21.97; P<0.05). Pairwise comparisons were between groups, CH, CRF: the difference between the DR group and the NDM group and the NDR group was statistically significant (P<0.05); CCT: the difference between the DR group and the NDM group was statistically significant (P<0.05), and The difference in the NDR group was not statistically significant (P>0.05). CCT, CH, CRF: the difference between the NDR group and the NDM group was not statistically significant (P>0.05). The results of multiple linear regression analysis showed that CCT and IOPcc in DR patients were independent influencing factors of CH [CCT: β=0.01, 95% confidence interval (CI) 0.01-0.03, P=0.013; IOPcc: β=－0.15, 95%CI －0.25-－0.05, P=0.005]; Age, CCT, IOPcc were independent influencing factors of CRF [Age: β=－0.06, 95%CI －0.09-－0.03, P＜0.001; CCT: β=0.01, 95%CI 0.00-0.02, P=0.049; IOPcc: β=0.16, 95%CI 0.07-0.25, P=0.001]. The comparison of CCT, CH, CRF, adjusted CH, and adjusted CRF of the eyes in the NDR group, NPDR group, and PDR group were statistically significant (F=3.76, 5.36, 12.61, 6.59, 10.41; P<0.05). Pairwise comparison between groups, CH, CRF, adjusted CH, adjusted CRF: the difference between the NPDR group, the PDR group and the NDR group was statistically significant (P<0.05), and the difference between the PDR group and the NPDR group was not statistically significant (P>0.05); CCT: The difference between NPDR group and NDR group, PDR group and NPDR group was not statistically significant (P>0.05), and the difference between PDR group and NDR group was statistically significant (P<0.05). ConclusionThe CH and CRF of eyes with T2DM and DR are elevated; CCT and IOPcc are independent influencing factors of CH, and age, CCT and IOPcc are independent influencing factors of CRF.
In order to understand how the biomechanical properties of rabbit cornea change over time after corneal ablation, 21 healthy adult rabbits were used in this study, with the left eye as experimental side and the right eye as the control side. Firstly, a lamellar knife was used to remove a portion of the anterior corneal surface tissue (30%~50% of the original corneal thickness) from the left eye of each rabbit, as an animal model simulating corneal refractive surgery. Secondly, postoperative experimental rabbits were kept for one, three, or six months until being euthanized. Strip specimens were produced using their corneas in vitro to perform a uniaxial tensile test with an average loading-unloading rate of approximately 0.16 mm/s. Finally, the visco-hyperelastic material constitutive model was used to fit the data. The results showed that there was a significant difference in the viscoelastic parameters of the corneas between the experimental and the control eyes at the first and third postoperative months. There was a difference in tangential modulus between the experimental and the control eyes at strain levels of 0.02 and 0.05 at the third postoperative month. There was no significant difference in biomechanical parameters between the experimental and the control eyes at the sixth postoperative month. These results indicate that compared with the control eyes, the biomechanical properties of the experimental eyes vary over postoperative time. At the third postoperative month, the ratio of corneal tangential modulus between the experimental and the control eyes significantly increased, and then decreased. This work lays a preliminary foundation for understanding the biomechanical properties of the cornea after corneal refractive surgery based on rapid testing data obtained clinically.
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 investigate the feasibility of photochemical tissue bonding (PTB) technique in repairing limbal stem cell (LSC) deficiency and the effect on cornea wound healing. Methods LSCs were isolated from limbus of New Zealand rabbits by tissue block culture method, and then the LSCs of 2nd passage were cultured on de-epithelialized human amniotic membrane (HAM) for 3 weeks to prepare the HAM/LSC grafts. The LSC deficiency models of the left eyes were established by 0.5 mol/L NaOH in 24 New Zealand female rabbits, aged 3-4 months and weighing 1.5-2.0 kg. HAM/LSC grafts were used to repair the cornea wounds by sutures (suture group, n=12) or by PTB technique (PTB group, n=12). The gross was observed including the corneal transparency, erythema, and new blood vessel formation after surgery. At 3 and 28 days, the inflammatory cytokine of interleukin 1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α) were assayed by ELISA method; and the amount of new blood vessels were quantified by immunohistochemistry staining at 28 days. Results All animals survived to the end of the experiment. At 3 days, there was no obvious difference in the corneal transparency between 2 groups; at 28 days, the corneal transparency of PTB group was higher than that of suture group, and new blood vessels decreased. HE staining showed that mass inflammatory cells infiltrated between graft and cornea basal layer at 3 days, and no new blood vessel formed. inflammatory cells infiltration significantly decreased at 28 days in PTB group; the amount of new blood vessels was (2.0 ± 0.8)/ HP in PTB group and was (6.3 ± 1.3)/HP in suture group, showing significant difference (t=7.966, P=0.002). At 28 days, the concentrations of inflammatory cytokine of IL-1β, IL-6, and TNF-α in suture group were significantly higher than those in PTB group (P lt; 0.05); however, no significant differences were observed between 2 groups at 3 days (P gt; 0.05). Conclusion PTB technique can be used to fix HAM/LSC grafts, which can decrease inflammatory cell infiltration and new vessel formation, and improve the outcomes when compared with suture technique.
Objective To evaluate glaucoma and anterior chamber angle changes after intravitreal silicone oil injection(SOI). Methods The intraocular pressure(IOP) and anterior chamber angles of 34 e yes(33 patients)undergone pars plana vitrectomy and SOI were observed. Results Glaucoma occurred in 9 eyes(26%),in which silicone oil glaucoma(SOG) accounted for 77%(7/9).The changes of the superior part of anterior chamber angle were peripheral anterior synechiae in 11 eye(32%) and SO emulsification droplets in 22 eyes(64%) in 1～4.5 months after surgeries.Glaucoma occurred in 6 eyes of 7 eyes undergone peripheral iridectomy at the inferio r part of the iris after the closure of iridectomy holes (plt;0.05). Conclusion High incidence of glaucoma was found in this series of patients after intravitreal silicone oil injection,and the main causes of SOG were closure of the inferior iridecomy hole and silicone emulsification. (Chin J Ocul Fundus Dis, 2001,17:105-107)
Ocular neovascularization is a pathological change in various ocular diseases such as diabetic retinopathy, retinopathy of prematurity, central retinal vein occlusion and age-related macular degeneration, which seriously affects patient's vision. β receptors are expressed in conjunctiva, corneal epithelial cells, corneal endothelial cells, extraocular muscles, trabecular meshwork, ciliary muscle, lens and retina. β adrenergic receptor antagonists bind to β receptors to exert anti-angiogenic effects by inhibiting the expression of vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1, interleukin-6 and other angiogenic cytokines; reducing macrophage-related inflammatory response; increasing the expression of anti-angiogenic factors. In the treatment of corneal neovascularization, choroidal neovascularization, and retinopathy of prematurity, it can significantly reduce the area of neovascularization and delay disease progression. Co-administration of anti-VEGF drugs can reduce the frequency of administration of anti-VEGF drugs. At effective therapeutic concentrations, β-adrenergic receptor antagonists are well tolerated; they have broader targets than anti-VEGF drugs, which offers new treatment strategies for ocular neovascularization such as corneal, choroidal and retinal neovascularization.
Objective To investigate the clinical manifestations and gene mutation of a pedigree with retinal lattice degeneration and granular corneal dystrophy (GCD) type 2. Methods Ten members in 3 generations of a pedigree with retinal lattice degeneration and GCD2 were included in the study, including 6 patients (3 males and 3 females) and 4 healthy family members. All members underwent visual acuity, slit lamp microscope, three-mirror lens, fundus color photography, optical coherence tomography, and corneal endothelial cells counting. Genomic DNA was extracted from peripheral venous blood (2 ml) from all the subjects and their spouses, who had no related inherited diseases. The next generation sequencing method was used to detect the mutation sites of transforming growth factor β (TGFBI), and all results underwent Sanger verification. Results Among the 12 eyes of 6 patients, the visual acuity was FC/20 cm-1.0. In the superficial central corneal stroma, snowflake-like deposits were observed in three cases (6 eyes), and a small amount of granular deposits were observed in three cases (6 eyes). Corneal endothelial cell counts were normal. Retinal lattice degeneration were observed in 3 cases, 6 eyes (including 3 cases of rhegmatogenous retinal detachment in 4 eyes); retinal thinning without obvious lattice degeneration in 4 eyes of 2 patients. Nystagmus in 1 patient and fundus examination showed no significant abnormalities. DNA sequencing results showed that the proband and 4 patients had missense mutation of TGFBI gene in exon 4 c.371G＞ A, the mutation site corresponding to the amino acid change encoded by TGFBI gene No. 124 Amino acids, from arginine to histidine (p.R124H). Patients with this mutation have varying degrees of clinical phenotype. Conclusions The mutation of c.701G＞ A (p.R124H) in TGFBI gene is the causative gene of GCD in this pedigree. The patients with this mutation have different clinical phenotypes.
ObjectiveTo investigate whether the corneal shape recovered after discontinuation of long-term orthokeratology and whether orthokeratology increased the corneal astigmatism and ocular astigmatism.MethodsFrom December 2016 to April 2018, a retrospective study was conducted on 33 myopic patients who had undergone two times standard orthokeratology in the outpatient department of West China Hospital of Sichuan University, and had stopped wearing the first orthokeratology lens for one month before fitting the second orthokeratology lens. A total of 32 myopia frame glasses wearers were selected by simple random sampling as control. The changes of corneal flat meridian curvature (flat K), corneal steep meridian curvature (steep K), corneal astigmatism and ocular astigmatism before and after discontinuation of orthokeratology were analyzed.ResultsAmong the patients with baseline myopia diopter of −0.25～−2.75 D, the average annual change of corneal flat K was (−0.03±0.21) D in the frame glasses group and (−0.24±0.14) D in the orthokeratology group, the difference was statistically significant (t=5.555, P<0.001). Among the patients with baseline myopia diopter of −0.25～−2.75 D, the average annual change of corneal steep K was (0.20±0.42) D in the frame glasses group and (0.15±0.20) D in the orthokeratology group, the difference was not statistically significant (t=0.785, P=0.435). Among the patients with baseline myopia diopter of −3.00～−5.75 D, the average annual change of corneal steep K was (0.29±0.39) D in the frame glasses group and (−0.01±0.20) D in the orthokeratology group, the difference was statistically significant (t=2.758, P=0.014). The average changes of corneal astigmatism were analyzed according to the difference of eyes, gender, age and baseline corneal astigmatism, the difference was not statistically significant (P>0.05), respectively. For patients with baseline astigmatism absolute value less than or equal to 0.50 D, the astigmatism annual change of the frame glasses group was 0.00 (0.50) D, and that of orthokeratology group was −0.33 (0.48) D, the difference was statistically significant (Z=−2.301, P=0.021).ConclusionsThe flat K of the cornea becomes flatter and the steep K does not change after one month’s discontinuation of long-term orthokeratology. There was no difference in the increase of corneal astigmatism compared with those wearing frame glasses. When the baseline ocular astigmatism is less than or equal to 0.50 D, the increase of astigmatism may occur after discontinuation of orthokeratology.
In order to rescue the serious cornea-sclera defect, normal piece of a sclera from the damaged eye was used to serve as a donor material to repair the cornea-sclera defect. Eighteen cases were treated by transplantation of sclera graft with the operation to decompress the intra-ocular tension and to perform an artificial pupil from 1979 to 1994. Because the ocular-store seriously lacks in mostly internal locality, in the 18 cases, laceration of avulsive in 5 cases, severe corneal fistula complicated to other corneal diseases in 8 cases, locolized staphyloma of aornea in 2, laceration of sclera fistula in 1. The resulte were: The repairs were all healed up in an average of 20 days. The tension returned to normal and the vision was improved. The scleral graft was fused with the cornea, and the white area form the graft tended to reduce in size gradually with increase in transparency. There was no sign of iritis and rejection reaction. Follow-up of 3 to 36 months showed that the grafting operation was simple and an easy method, at the same time, once gained effect if would prevent or cure blindness.
Objective To investigate the influence of undercorrected orthokeratology on myopia control, and the correlation between target and central corneal epithelial damage. Methods A retrospective study was conducted on 22 undercorrected orthokeratology lens wearers (37 eyes) from January 2016 to February 2017, and 25 full corrected wearers (47 eyes) during the concurrent period were randomly selected as the control group. The changes of axial length before and after orthokeratology lens wearing and the within-6-month central corneal epithelial damage after orthokeratology lens wearing were analyzed. Results The average annual increase of axial length was (0.13±0.15) mm in the undercorrected group, and (0.14±0.16) mm in the full corrected group, the difference was not statistically significant (P>0.05). Multiple linear regression analysis showed that there was no correlation between the axial growth and the undercorrection of the target (P>0.05), but a negative correlation between the axial growth and the age (P<0.01). After using orthokeratology, the average annual growth of the axial length in children aged 7-10 years was (0.25±0.16) mm, and (0.10±0.14) mm in children aged 11-15 years, the difference was statistically significant (P<0.01). The incidence of central corneal epithelial punctate staining in the (–4.25)-(–5.00) D target group was 27.08%, and that in the (–3.00)-(–4.00) D target group was 16.67%, the difference was not statistically significant (P>0.05). Conclusions The effect of orthokeratology on myopia growth is not affected by the undercorrected target, not related to the undercorrection of target, but negatively correlated with the age. Undercorrected orthokeratology can still be used for myopia control in high myopia patients. No correlation is found between the target and central corneal staining.