Inhibited experimental corneal neovascularization by neutralizing anti-SDF-1α antibody

AIM: To explore the effect of SDF-1α on the development of experimental corneal neovascularization (CRNV). METHODS: CRNV was induced by alkali injury in mice. The expression of SDF-1α and CXCR4 in burned corneas was examined by Flow Cytometry. Neutralizing anti-mouse SDF-1α antibody was locally administrated after alkali injury and the formation of CRNV 2 weeks after injury was assessed by Immunohistochemistry. The expression of VEGF and C-Kit in burned corneas was detected by RT-PCR. RESULTS: The number of CRNV peaks at 2 weeks after alkali injury. Compared to control group, SDF-1α neutralizing antibody treatment significantly decreased the number of CRNV. RT-PCR confirmed that SDF-1α neutralizing antibody treatment resulted in decreased intracorneal VEGF and C-Kit expression. CONCLUSION: SDF-1α neutralizing antibody treated mice exhibited impaired experimental CRNV through down regulated VEGF and C-Kit expression.     

Inhibitory effects of regorafenib, a multiple tyrosine kinase inhibitor, on corneal neovascularization

AIM:To evaluate the inhibitory effects of regorafenib (BAY 73-4506), a multikinase inhibitor, on corneal neovascularization (NV).METHODS:Thirty adult male Sprague-Dawley rats weighing 250-300 g, were used. Corneal NV was induced by NaOH in the left eyes of each rat. Following the establishment of alkali burn, the animals were randomized into five groups according to topical treatment. Group 1 (n = 6) received 0.9% NaCl, Group 2 (n = 6) received dimethyl sulfoxide, Group 3 (n = 6) received regorafenib 1 mg/mL, Group 4 (n =6) received bevacizumab 5 mg/mL and Group 5 (n = 6) received 0.1% dexamethasone phosphate. On the 7d, the corneal surface covered with neovascular vessels was measured on photographs as the percentage of the cornea’s total area using computer-imaging analysis. The corneas obtained from rats were semiquantitatively evaluated for caspase-3 and vascular endothelial growth factor by immunostaining.RESULTS:A statistically significant difference in the percent area of corneal NV was found among the groups (P <0.001). Although the Group 5 had the smallest percent area of corneal NV, there was no difference among Groups 3, 4 and 5 (P >0.005). There was a statistically significant difference among the groups in apoptotic cell density (P = 0.002). The staining intensity of vascular endothelial growth factor in the epithelial and endothelial layers of cornea was significantly different among the groups (P <0.05). The staining intensity of epithelial and endothelial vascular endothelial growth factor was significantly weaker in Groups 3, 4 and 5 than in Groups 1 and 2.CONCLUSION: Topical administration of regorafenib 1 mg/mL is partly effective for preventing alkali-induced corneal NV in rats.     

Experimental model of Fusarium solani keratitis in rats

AIM: To establish a repeatable rat model of Fusarium solani keratitis (F. solani keratitis) that mimicked fungal keratitis in humans. METHODS: Wistar rats’ corneas were scratched on the superficial stroma after scraping the unilateral corneal epithelia. Then, the corneal surface was inoculated with different inoculum dose of F. solani spore suspension. Doses ranged from 106 to 109 colony-forming unit per milliliter (CFU/mL). The treated corneas were covered by contact lenses that were made of Parafilm M membrane. Negative controls were inoculated with sterile phosphate-buffered saline (PBS). For statistical analysis, corneas were evaluated daily on a 12-point scale to check the state of corneal inflammation. Furthermore, the pathological characteristics of this model were investigated. RESULTS: The rat model of F. solani keratitis was established by the combination methods of corneal trauma and parafilm-made contact lens and inoculation of fungus spore suspension. 106 and 107CFU/mL of F. solani induced mild corneal infection, while 108CFU/mL of F. solani was sufficient to induce moderate infection that was consistent with human keratomycosis. Dose of 109CFU/mL of F. solani was excessive and led to perforated corneas. CONCLUSION: The rat model of F. solani keratitis, established by the combinational methods of corneal trauma, parafilm-made contact lens and the appropriate dose of inoculum, that imitates the developing processes of F. solani keratitis in human beings and provides a repeatable method of creating a rat model.     

Efficacy of the nucleotide-binding oligomerzation domain 1 inhibitor Nodinhibit-1 on corneal alkali burns in rats

AIM:To evaluate the therapeutic effect of Nodinhibit-1 on alkali-burn-induced corneal neovascularization (CNV) and inflammation.The nucleotide-binding oligomerzation domain 1 (NOD1) is a potent angiogenic gene.METHODS:The alkali-burned rat corneas (32 right eyes) were treated with eye drops containing Nodinhibit-1 or phosphate buffered solution (PBS, PH 7.4) only, four times per day. CNV and inflammation were monitored using slit lamp microscopy, and the area of CNV was measured by formula. Vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) was determined by Western blot analysis. The TUNEL assay was used to assess the corneal apoptosis cells.RESULTS:Alkali-burn-induced progressive CNV and inflammation in the cornea. After treatment for 7d and 14d, there were statistically significant differences in the CNV areas and inflammatory index on that between two group(P＜0.05, respectively). Epithelial defect quantification showed a significant difference between the two groups at days 4 and 7 after the alkali burns (P＜0.05). The apoptotic cells on days 1, 4, and 7 between the two groups showed significant differences at all time points (P<0.05, respectively). Compared to that in control group, the protein level of VEGF expression was significantly reduced whereas the PEDF expression was increase in the Nodinhibit-1 groups on day 14 (P＜0.05, respectively＝.CONCLUSION:Topical application of 10.0 μg/mL Nodinhibit-1 may have potential effect for the alkali burn-induced CNV and inflammation. The effect of Nodinhibit-1 on CNV may be by regulation the equilibrium of VEGF and PEDF in the wounded cornea.     

Anti-neovascular effect of chondrocyte-derived extracellular matrix on corneal alkaline burns in rabbits

Purpose

We investigated the effect of a chondrocyte-derived extracellular matrix (CDECM) on experimental corneal alkaline burns in rabbits.

Methods

Corneal neovascularization (NV) was induced by applying an 8-mm filter paper soaked in 1 N NaOH to the right central corneas of rabbits for 1 minute. Ten days later, the rabbits were randomly divided into three groups: the alkaline burn group, the CDECM transplantation group, and the human amniotic membrane (HAM) transplantation group. The left eyes were used as controls. CDECM and HAM were transplanted onto the corneal surface to completely cover the resected area and were subsequently sutured. On the 10th day after transplantation, the structural changes of the cornea were analyzed histologically. We examined the effects of CDECM on clinical NV features and on the expression of corneal NV markers.

Results

The alkaline burn produced significant NV and increased the corneal thickness. On day 10 after transplantation, the thickness, NV and opacity of the cornea were markedly decreased in the CDECM group (p?<?0.001). However, the HAM transplantation group did not exhibit improvements in these clinical parameters, and there were no significant differences relative to the burn group. In addition, the use of CDECM improved the healing of the cornea following the alkaline burn by disrupting the corneal epithelial proliferation and reducing the fibrotic changes of the stroma. The hallmarks of NV were significantly induced in the subepithelium by the alkaline burn, and these levels were also suppressed by CDECM. The CDECM suppressed corneal NV by inhibiting nuclear factor-kappa B (NF-κB) activation by blocking the PKC and Akt signaling pathways.

Conclusions

CDECM transplantation was markedly effective in healing alkali-burned corneas by modulating the translocation of NF-κB to the nucleus, thereby representing a promising material for the noninvasive treatment of ocular surface disease.     

The Effect of Bevacizumab on Corneal Neovascularization in Rabbits

Purpose

To determine the efficacy of topical application and subconjunctival injection of bevacizumab in the treatment of corneal neovascularization.

Methods

Corneal neovascularization was induced with a silk suture of the corneal stroma in 12 rabbits (24 eyes). One week after suturing, four rabbits were treated with topical bevacizumab at 5 mg/mL (group A) and another four rabbits were treated with topical bevacizumab 10 mg/mL (group B) in the right eyes twice a day for two weeks. A subconjunctival injection of bevacizumab 1.25 mg/mL was done in the right eyes of four rabbits (group C). All of the left eyes (12 eyes) were used as controls. The area of corneal neovascularization was measured after one and two weeks, and the concentration of vascular endothelial growth factor (VEGF) in corneal tissue was measured after two weeks.

Results

The neovascularized area was smaller in all treated groups than in the control group (p<0.001). Upon analysis of the neovascularized area, there was no significant difference between groups A and B. However, the mean neovascularized area of group B was significantly smaller than that of group C after two weeks of treatment (p=0.043). The histologic examination revealed fewer new corneal vessels in all treated groups than the control group. The concentration of VEGF was significantly lower in all treated groups compared to the control group (p<0.01), but no difference was shown between treated groups.

Conclusions

Topical and subconjunctival bevacizumab application may be useful in the treatment of corneal neovascularization and further study is necessary.     

The Effect of Bevacizumab versus Ranibizumab in the Treatment of Corneal Neovascularization: A Preliminary Study

Purpose

To compare the short term effects of bevacizumab and ranibizumab injections on the regression of corneal neovascularization (NV).

Methods

Sixteen eyes of 16 patients with corneal NV were randomly assigned for an injection with 2.5 mg of bevacizumab (group 1, n = 8) or 1 mg of ranibizumab (group 2, n = 8) through subconjunctival and intrastromal routes. The patients were prospectively followed-up for one month after the injections. Corneal NV areas, as shown on corneal slit-lamp photographs stored in JPEG format, were calculated using Image J software before the injection, one week after the injection, and one month after the injection. The corneal NV areas were compared before and after the injections.

Results

Seven women and nine men, with an average age of 51 years, presented with corneal NV secondary to herpetic keratitis (7 cases), graft rejection (6), chemical burn (1), pemphigoid (1), and recurrent ulcer (1). In group I, the preoperative corneal NV area (8.75 ± 4.33%) was significantly decreased to 5.62 ± 3.86% one week after the injection and to 6.35 ± 3.02% one month after the injection (p = 0.012, 0.012, respectively). The corneal NV area in group 2 also exhibited a significant change, from 7.37 ± 4.33% to 6.72 ± 4.16% one week after the injection (p = 0.012). However, no significant change was observed one month after the injection. The mean decrease in corneal NV area one month after injection in group 1 (28.4 ± 9.01%) was significantly higher than in group 2 (4.51 ± 11.64%, p = 0.001).

Conclusions

Bevacizumab injection resulted in a more effective and stable regression of corneal NV compared to the ranibizumab injection. The potency and dose of these two drugs for the regression of corneal NV require further investigation.     

Effects of amniotic membrane transplantation on cytokines expression in chemically burned rat corneas

AIM: To investigate the effect of amniotic membrane transplantation (AMT) on the expressions of inflammatory-related, angiogenic-related and growth-related cytokines in rat corneas after chemical injury. METHODS: Alkali wounds were inflicted on the central corneas of rats by applying a round filter paper soaked in 1mol/L NaOH for 40 seconds. One week after alkali burn, 12 rats were randomly divided into 2 groups: the AMT group and the control group, and AMT was performed on the rats in the AMT group. Corneal opacity and neovascularization were observed by slit-lamp microscopy. The protein levels of interleukin (IL)-2, interferon (IFN)-γ, IL-10 and transforming growth factor (TGF)-β were determined by enzyme-linked immunosorbent assay 2 weeks after AMT. The mRNA levels of matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were evaluated by real-time quantitative PCR. RESULTS: In the AMT group, the corneal opacity was improved (P=0.011) and the area of corneal neovascularization was significantly decreased (P=0.005) compared with the control group. The amount of IL-2 and IFN-γ secreted by Th1 cells were decreased after AMT, whereas the amount of IL-10 and TGF-β secreted by Th2 cells were increased (P<0.05). The level of MMP-2 was significantly down-regulated (P=0.013) at the mRNA level in the AMT group, while the expression of EGF was significantly higher (P=0.022) compared with controls. CONCLUTION: AMT may suppress corneal neovascularization after chemical injury by modulating the expressions of soluble factors.     

Concentration of Vascular Endothelial Growth Factor After Intracameral Bevacizumab Injection in Eyes With Neovascular Glaucoma

Purpose

To study the concentration of vascular endothelial growth factor (VEGF) in the aqueous humor before and after intracameral injection of bevacizumab in eyes with neovascular glaucoma, and to detect the duration of an anti-VEGF effect of bevacizumab in the anterior chamber.

Methods

In this prospective interventional case series, 1.25 mg of bevacizumab was injected into the anterior chamber of five eyes in five neovascular glaucoma patients. Aqueous humor samples were obtained just before intracameral injection of bevacizumab and two weeks after injection. The concentrations of VEGF in the aqueous humor were measured using ELISA. To investigate corneal endothelial damage after intrecameral bevacizumab injection, specular microscopy was performed before injection and two weeks after injection. Slit lamp photo and iris fluorescent angiography was performed to determine the regression of iris neovascularization.

Results

After injection, substantial regression of neovascularization or fluorescein leakage was seen in all treated eyes. The VEGF concentrations in the aqueous humor in eyes with NVG were 1181.8±1248.3 pg/mL before intracameral injection of bevacizumab. Two weeks after injection, the VEGF concentrations decreased to 33.2±12.2 pg/mL (p=0.04, Wilcoxon signed rank test). There were no significant changes in IOP or corneal endothelial cells.

Conclusions

Intracameral bevacizumab injection can remarkably reduce iris neovascularization in neovascular glaucoma patients. VEGF levels were significantly decreased two weeks after injection and corneal toxicity was not observed during short term follow-up.     

Safety of bevacizumab on extraocular muscle in a rabbit model

Purpose

The purpose of this study was to investigate the myotoxicity of bevacizumab on extraocular muscles in a rabbit model.

Methods

Thirty New Zealand white rabbits were used for this study. The animals were evenly divided into two groups. In the first group, 15 rabbits were treated with intramuscular injections of bevacizumab (1.25 mg/0.05 mL) in the right superior rectus muscle and normal saline solution (0.05 mL) in the left superior rectus muscle. In the second group, 15 rabbits were treated with subconjunctival injections of bevacizumab (2.5 mg/0.1 mL) in the right superior subconjunctival area and normal saline solution (0.1 mL) in the left superior subconjunctival area. Five rabbits in each group were sacrificed at one day, two weeks and four weeks after the injections. Extraocular muscle samples were prepared for light microscopic (LM) and electron microscopic (EM) examination. Degrees of acute inflammation were evaluated via CD-11b immunohistochemistry, and global muscle change was investigated using hematoxylin and eosin stains. Intensity of fibrosis was evaluated using Masson trichrome stains, and ultrastructural changes were observed on EM.

Results

We observed no significant inflammatory cell infiltration, muscle necrosis or fibrotic change in treated and control eyes. EM findings revealed no significant damage to muscle or vascular tissue after bevacizumab injection.

Conclusions

We found no signs of extraocular muscle toxicity after LM and EM intramuscular and subconjunctival bevacizumab injections in a rabbit model.     

Biometric Risk Factors for Corneal Neovascularization Associated with Hydrogel Soft Contact Lens Wear in Korean Myopic Patients

Purpose

To investigate the biometric risk factors for corneal surface complications associated with hydrogel soft contact lens (SCL) fitting in myopic patients in Korea.

Methods

This is a retrospective case-control study. The records of 124 subjects (124 eyes) who wore SCLs on a daily basis were reviewed. Thirty-one patients (31 eyes) who were diagnosed with corneal neovascularization (NV) while wearing SCLs were included in the complication group. Ninety-three age- and sex-matched patients (93 eyes) who wore SCLs, who did not have corneal NV and who visited our clinic for correction of refractive errors were included in the control group. The degree of spherical equivalent, astigmatism and corneal base curve radius (BCR) were compared in both groups.

Results

Patients with NV exhibited poorer best corrected visual acuity and more myopia than controls (p = 0.008 and 0.006, respectively). In univariate analysis, highly myopic patients (-9 diopters [D] or higher) were more likely to experience NV (odds ratio [OR], 2.232; 95% confidence interval [CI], 1.602 to 3.105). High astigmatism (≥2 D) increased the risk of complications (OR, 2.717; 95% CI, 1.141 to 6.451). Steep cornea, in which BCR was <7.5 mm, also raised the risk of complications (OR, 4.000; 95% CI, 1.661 to 9.804). Flat cornea was not a risk factor for the development of NV.

Conclusions

High myopia, high astigmatism, and steep cornea seemed to be risk factors in the development of corneal NV in SCL wearers.     

Ultrastructural pathology of corneal neovascu-larization after photodynamic therapy in rabbits

AIM: To investigate the ultrastructural pathogenesis of photodynamic therapy (PDT) for the experimental corneal neovascularization (CNV) by Hematoporphyrin Derivate (HPD) as photosensitizer and Argon laser as light source. METHODS: Experimental CNV models were induced in 7 white rabbits using alkali burn. Six weeks after models establishment, animals with CNV were injected with HPD intravenously, and 48 hours after the injection, 7 eyes were irradiated with argon laser (power 800mw, wavelength 514.5nm, spot diameter 200μm, exposure time 2ms). The irradiated CNV was observed by light microscopy and scanning electron microscopy. RESULTS: Histopathological study indicated that there was a striking decrease in the number of the CNV, vascular endothelium became degeneration and necrosis, some vessels were atrophy and attenuated, and vessels cavity were blocked by some thrombosis. No obvious abnormal histopathological findings were noted in surrounding tissues. CONCLUSION: The high precise action on CNV and minimal damage to surrounding tissues with PDT by HPD as photosensitizer suggested that PDT might be an effective and safe modality in the treatment of CNV.     

Transplantation of tissue-engineered human corneal epithelium in limbal stem cell deficiency rabbit models

AIM: To evaluate the biological functions of tissue-engineered human corneal epithelium (TE-HCEP) by corneal transplantation in limbal stem cell deficiency (LSCD) rabbit models. METHODS: TE-HCEPs were reconstructed with DiI-labeled untransfected HCEP cells and denuded amniotic membrane (dAM) in air-liquid interface culture, and their morphology and structure were characterized by hematoxylin-eosin (HE) staining of paraffin-sections, immunohistochemistry and electron microscopy. LSCD models were established by mechanical and alcohol treatment of the left eyes of New Zealand white rabbits, and their eyes were transplanted with TE-HCEPs with dAM surface outside by lamellar keratoplasty (LKP). Corneal transparency, neovascularization, thickness, and epithelial integrality of both traumatic and post transplantation eyes were checked once a week by slit-lamp corneal microscopy, a corneal pachymeter, and periodic acid-Schiff (PAS) staining. At day 120 post surgery, the rabbits in each group were sacrificed and their corneas were examined by DiI label observation, HE staining, immunohistochemistry and electron microscopy. RESULTS: After cultured for 5 days on dAM, HCEP cells, maintaining keratin 3 expression, reconstructed a 6-7 layer TE-HCEP with normal morphology and structure. The traumatic rabbit corneas, entirely opaque, conjunctivalized and with invaded blood vessels, were used as LSCD models for TE-HCEP transplantation. After transplantation, obvious edema was not found in TE-HCEP-transplanted corneas which became more and more transparent, the invaded blood vessels reduced gradually throughout the monitoring period. The corneas decreased to normal thickness on day 25, while those of dAM eyes were over 575μm in thickness during the monitoring period. A 4-5 layer of epithelium consisting of TE-HCEP originated cells attached tightly to the anterior surface of stroma was reconstructed 120 days after TE-HCEP transplantation, which was similar to the normal control eye in morphology and structure. In contrast, intense corneal edema, turbid, invaded blood vessels were found in dAM eyes, and no multilayer epithelium was found but only a few scattered conjunctiva-like cells appeared. CONCLUSION: The TE-HCEP, with similar morphology and structure to those of innate HCEP, could reconstruct a multilayer corneal epithelium with normal functions in restoring corneal transparency and thickness of LSCD rabbits after transplantation. It may be a promising HCEP equivalent for clinical therapy of corneal epithelial disorders.     

β-catenin expression in rat neovascularized cornea after alkali burn

AIM: To investigate the expression of β-catenin in cornea after alkali burn and explore its role in cornea neovascularization (CNV). METHODS: CNV model was established by putting filter paper with the size of 3.0mm in diameter immersed in 1mol/L NaOH solution on the left cornea of rat for 20 seconds. Twenty-five Sprague Dawley rats were randomly divided into 5 groups: post-operation 1-, 4-, 7-, 14- and 21-day groups while the right eyes as normal control group. The expression level of β-catenin protein, mRNA and VEGF were determined at the 1st, 4th, 7th, 14th and 21st day following the establishment of model by RT-PCR and immunohistochemical technique. RESULTS: No expression of β-catenin immunoreactivity was detected in normal cornea. The expressions of β-catenin and VEGF both reached the peak at the 4th and 7th day and gradually decreased to near baseline 21 days later. Alteration of β-catenin and VEGF levels showed a significant positive correlation (r=0.855, P<0.05). CONCLUSION: The levels of β-catenin are markedly related to inflammatory CNV in rat cornea after alkali burn.     

Limbal Stem Cell Allografts and Corneal Transplant in a Patient with Severe Corneal Melting and Perforation due to Thermokeratoplasty and Cross-Linking Treatment Burn

Purpose

To report corneal stem cell allografts in a patient with a persistent epithelial defect as well as corneal melting and perforation due to severe ultraviolet light burn and thermokeratoplasty treatment for keratoconus.

Methods

A 21-year-old female patient with corneal melting, perforation and a persistent epithelial defect in her left eye secondary to iatrogenic treatment for keratoconus, thermokeratoplasty and cross-linking was treated with penetrating keratoplasty, using a 9.0-mm diameter corneal graft and limbal stem cell allograft implants. At the end of the procedure, subtenonian injections of a combination of bevacizumab and triamcinolone were given.

Results

The patient had a favorable outcome 48 h after surgery, with an improvement of symptoms and a complete corneal healing. By the third week after surgery, she had a best-corrected visual acuity of 20/60 and a clear corneal graft, which remained stable for the 9 months of follow-up.

Conclusions

Treatment with limbal stem cell allografts and penetrating keratoplasty in a female patient with a large corneal defect and melting in her left eye was effective. Larger studies are warranted to explore the real impact of this procedure.Key words: Stem cells, Corneal melting, Thermokeratoplasty, Thermal burn     

Acellular porcine corneal matrix as a carrier scaffold for cultivating human corneal epithelial cells and fibroblasts in vitro

AIM: To investigate the feasibility of corneal anterior lamellar reconstruction with human corneal epithelial cells and fibroblasts, and an acellular porcine cornea matrix (APCM) in vitro. METHODS: The scaffold was prepared from fresh porcine corneas which were treated with 0.5% sodium dodecyl sulfate (SDS) solution and the complete removal of corneal cells was confirmed by hematoxylin-eosin (HE) staining and 4’, 6-diamidino-2-phenylindole (DAPI) staining. Human corneal fibroblasts and epithelial cells were cultured with leaching liquid extracted from APCM, and then cell proliferative ability was evaluated by MTT assay. To construct a human corneal anterior lamellar replacement, corneal fibroblasts were injected into the APCM and cultured for 3d, followed by culturing corneal epithelial cells on the stroma construction surface for another 10d. The corneal replacement was analyzed by HE staining, and immunofluorescence staining. RESULTS: Histological examination indicated that there were no cells in the APCM by HE staining, and DAPI staining did not detect any residual DNA. The leaching liquid from APCM had little influence on the proliferation ability of human corneal fibroblasts and epithelial cells. At 10d, a continuous 3 to 5 layers of human corneal epithelial cells covering the surface of the APCM was observed, and the injected corneal fibroblasts distributed within the scaffold. The phenotype of the construction was similar to normal human corneas, with high expression of cytokeratin 12 in the epithelial cell layer and high expression of vimentin in the stroma. CONCLUSION: Corneal anterior lamellar replacement can be reconstructed in vitro by cultivating human corneal epithelial cells and fibroblasts with an acellular porcine cornea matrix. This laid the foundation for the further transplantation in vivo.     

Is it safe to discharge treated proliferative diabetic retinopathy patients from the hospital eye service to a community screening programme?

Purpose

To investigate the distribution of new vessels (NV) in patients treated with pan-retinal photocoagulation for proliferative diabetic retinopathy (PDR). To assess whether it is safe to discharge treated PDR patients to the NHS Diabetic Eye Screening Programme (DESP) which uses two mydriatic 45° fields of each eye.

Methods

Consecutive treated PDR patients undergoing fundus fluorescein angiography between July 2010 and October 2011 for the purpose of looking for NV were included. The distribution of NV was mapped. In particular it was noted whether NV occurred in the area covered by the DESP standard screening images.

Results

A total of 76 patients (108 eyes) met the inclusion criteria for the study. Leaking NV were found inside the DESP fields in 89% of study patients. In 108 eyes with leaking NV, there were a total of 35 NVD and 336 NVE. NV were found within DESP fields in 83% of eyes. Of the 336 NVE, 54% occurred within and 46% outside DESP standard fields. There was no statistically significant difference in the retinal quadrant distribution of NVE.

Conclusions

If these findings apply to the whole treated PDR population, NVE would be identified in 89% of patients undergoing DESP screening. This would support stable treated PDR patients being monitored within the DESP. We found no preferential clustering of NV within quadrants or between posterior and less posterior retina suggesting that there would be no benefit to the DESP of taking an additional field or graders concentrating on one particular quadrant more than another.     

Evaluation of immersion 20 MHz B-scan ultrasonography in observing lens in the alkali burn eyes

AIM:To evaluate the accuracy of 20 MHz immersion B-scan ultrasonography in observing lens and to investigate the value of this noninvasive preoperative diagnosis method in alkali burn eyes.METHODS: It was a comparative study. Fifty-six cases (56 eyes) of alkali burn eyes were examined by ultrasound biomicroscopy (UBM) and immersion 20 MHz B-scan ultrasonography from June 2011 to April 2013, the images were analyzed, and the ultrasonographic diagnosis compared with the operation results.RESULTS: In 56 alkali burn eyes examined by UBM, the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; the anterior lens capsule surface or/and the front lens could be detected in 18 eyes, and lens opacification in 3 eyes of them; suspected abnormal lens were detected in the other 20 eyes. In all the same eyes examined by immersion 20 MHz B-scan ultrasonography, the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; 24 abnormal lens (opacity, lens expansion, shrinkage) and 14 normal lens were found. Compared with the intraoperative findings, the diagnostic accordance rate of the immersion 20 MHz B-scan appearance of lens was 100% (56/56), which was significantly higher than examined by UBM 57.14% (32/56) (χ²=30.55, P=0.0000).CONCLUSION:Immersion 20 MHz B-scan ultrasonography can observe the lens accurately in alkali burn eyes. It has important clinical value to combine with UBM in eyes of alkali burn.