Evaluation of morphological features: femtosecond-LASIK flap vs. SMILE cap, and the effects on corneal higher-order aberrations.

PURPOSE: The aim of this study is to evaluate morphological features of corneal flap/cap and the correlations with corneal higher-order aberrations (HOAs) changes after femtosecond laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). METHODS: This was a retrospective study. Pre- and postoperative (1 and 3 months) corneal HOAs were assessed with Pentacam HR. The corneal flap/cap thickness at 32 points (± 1.5 mm, ± 2 mm, ± 2.5 mm, and ± 3 mm from the corneal vertex on meridian 0°/45°/90°/135°) were measured using anterior segment optical coherence tomography at 3 months postoperatively. Morphological features of corneal flap/cap including predictability (P), uniformity (U), and symmetry (S) were calculated and used for correlation analysis with corneal HOAs changes. RESULTS: Eighty-six eyes (44 patients) and ninety-six eyes (50 patients) were involved in FS-LASIK and SMILE groups, respectively. Significant thicker corneal flap/cap than the predicted was observed at each measuring point and meridian in both groups (difference > 2.225 µm, the within-subject standard deviation over 6-mm optical zone). There was no statistically significant difference in predictability of corneal flap/cap thickness, while U6 mm (P < .0001), U0 (P < .001), U45 (P = .002), U90 (P < .0001), U135 (P = .004), S6 mm (P < .0001), S0 (P < .001), and S90 (P < .0001) over 6 mm zone were less in SMILE than in FS-LASIK. The changes of corneal tHOAs, Z (3, - 1), Z (3, 1), and SA were significantly correlated with morphological features of corneal flap/cap. CONCLUSION: Both FS-LASIK and SMILE had good predictability in flap or cap thickness, while the uniformity and symmetry of SMILE cap were better than FS-LASIK flap. The quality of flap/cap was closely associated with the changes of corneal HOAs.

Microvascular comparison in younger and older patients with retinal vein occlusion analyzed by OCT angiography.

BACKGROUND: To compare changes in retinal microvasculature of young and elderly patients with retinal vein occlusion (RVO) after anti-VEGF treatment. METHODS: RVO patients who underwent anti-VEGF treatment were retrospectively reviewed and categorized into two groups based on age. The OCT angiography images were obtained during each visit. Best corrected visual acuity (BCVA), vessel density (VD) and foveal avascular zone (FAZ) were measured and compared between the two groups. Vision improvements and retinal microvasculature changes were also correlated. RESULTS: Twenty patients with 20 eyes were enrolled in the younger group and 46 patients with 46 eyes were enrolled in the older group. Younger patients demonstrated better BCVA, higher VD and smaller FAZ than older patients at 12 months after the first anti-VEGF treatment. The improvement of VD was observed only in the younger group. A positive correlation between vision improvement and VD increase was noted. CONCLUSIONS: Young patients with RVO can achieve rapid rehabilitation of deep retinal vasculature which lead to a better visual outcome.

Multifractal and lacunarity analyses of microvascular morphology in eyes with diabetic retinopathy: A projection artifact resolved optical coherence tomography angiography study.

OBJECTIVE: To evaluate the degree of microvascular impairment in DR using multifractal and lacunarity analyses and to compare the diagnostic ability between traditional Euclidean measures (fovea avascular zone area and vessel density) and fractal geometric features. METHODS: This retrospective cross-sectional study included a total of 143 eyes of 94 patients with different stages of DR. The retinal microvasculature was imaged by projection removed OCTA. We examined the degree of association between fractal metrics of the retinal microvasculature and DR severity. The area under the ROC curve was used to estimate the diagnostic performance. RESULTS: With increasing DR severity, the multifractal spectrum shifted toward the left bottom and exhibited less left skewness and asymmetry. The vessel density, multifractal features, and lacunarity measured from the DCP were strongly associated with DR severity. The multifractal feature D5 showed the highest diagnostic ability. The combination of multifractal features further improved the discriminating power. CONCLUSIONS: Multifractal and lacunarity analyses can be potentially valuable tools for assessment of microvascular impairments in DR. Multifractal geometric parameters exhibit a better discriminatory performance than Euclidean measures, particularly for detection of the early stages of DR.

Evaluation of Scheimpflug imaging parameters in blepharospasm and normal eyes.

BACKGROUND: To investigate changes in corneal elevation, pachymetry, and keratometry in discriminating between normal and blepharospasm eyes, as measured by the Pentacam rotating Scheimpflug camera. METHODS: This was a prospective, cross-sectional study. A total of 47 consecutive patients with a range of blepharospasm severity and 40 age- and sex- matched healthy subjects were included, one eye of each subject was randomly chosen for data analysis. Blepharospasm severity was evaluated using the Jankovic scale and categorized as mild, moderate, or severe. Corneal parameters were measured by the Pentacam rotating Scheimpflug camera to derive corneal tomography information. Various parameters regarding keratometry, elevation at the anterior and posterior corneal surface, pachymetric data, final D value, and topometric indices from the Pentacam software were recorded, and the relationship between the blink rate and corneal parameters was analyzed. Intraclass correlation coefficients (ICCs) were assessed to evaluate the repeatability of intraobserver. RESULTS: Increased topographic asymmetry was observed in moderate and severe blepharospasm. Front K1and front Km were significantly higher in cases of mild (P < 0.05), moderate (P < 0.0001), and severe (P < 0.0001) blepharospasm as compared with controls. Front K2, back K1, back K2, and back Km were significantly higher in cases of moderate (P < 0.01) and severe (P < 0.001) blepharospasm as compared with controls. For corneal topometric indices, both ISV and IVA were significantly increased in severe blepharospasm (P < 0.05). Radii minimum were significantly increased in cases of moderate and severe blepharospasm (P < 0.05).There were no differences in corneal elevation and corneal pharcymetric parameters among the four groups, except for front BFS, which was significantly different in blepharospasm groups (P < 0.05). Final D values were significantly higher in the severe blepharospasm (P < 0.01) group than that among controls. There were significant correlations between the blink rate and most corneal tomographic parameters. All parameters showed high reproducibility (ICC: 0.921-0.996) for normal and blepharospasm subjects. CONCLUSIONS: Blepharospasm may lead to a redistribution of the pressure applied by the lids over the cornea and, consequently, may result in corneal shape changes, which can be documented through corneal topography.

Case report: Advanced modified pneumatic retinopexy for treating simultaneous bilateral rhegmatogenous retinal detachment.

Background: Simultaneous bilateral rhegmatogenous retinal detachment (RRD) is a rare and challenging condition in ophthalmology. This case report focuses on a modified pneumatic retinopexy technique, designed to improve treatment outcomes for this difficult condition. Case presentation: A 59-year-old male presented with decreased visual acuity in his right eye for one week. Examination revealed extensive retinal detachment in the right eye with multiple superior breaks and macula off, separated by approximately 3 clock hours. The left eye exhibited one quartile of retinal detachment with superior breaks and macula on. Bilateral simultaneous PR was performed for retinal repair. In the modified PR procedure, 0.7 ml of low-concentration perfluoropropane and 0.7 ml of filtered pure air were intravitreally injected into the right and left eyes, respectively. A head position maneuver was then employed to sequentially close retinal breaks, followed by laser photocoagulation once the surrounding retina reattached. Two days after gas injection, both retinas were completely reattached. Best corrected visual acuity improved to 0.6 in the right eye and 0.9 in the left eye at the 8-month follow-up. Conclusion: The innovative modified pneumatic retinopexy technique presented in this case report offers a promising new approach for effectively treating simultaneous bilateral rhegmatogenous retinal detachment.

[Correlation of optic retinal nerve fiber layer thickness and visual function in patients with nonproliferative diabetic retinopathy].

OBJECTIVES: To investigate the change of optic retinal nerve fiber layer (RNFL) thickness in nonproliferative diabetic retinopathy (NPDR) and to evaluate the correlation between the optic RNFL structural change and visual function. METHODS: A cross-sectional study. All cases came from ophthalmology department of Zhejiang Province Traditional Chinese Medical Hospital, and the First People's Hospital of Ningbo, and Zhongshan Ophthalmic Center, Sun Yat-Sen University from December 2009 to October 2012. All the disease and control cases were coming from the same hospitals at the same period. Subjects were divided into 3 different groups: patients with NPDR (n = 89, 89 eyes), patients with diabetic mellitus but without diabetic retinopathy (NRD) (n = 96, 96 eyes) and disease-free controls (n = 115, 115 eyes). One eye of each subject was randomly selected for study. Participants aged from 40 to 70 years at baseline and all diabetic patients had a diabetic history of at least 5 years. Optic RNFL thickness of each subject was measured by spectral domain optical coherence tomography(SD-OCT). Visual function examinations including contrast sensitivity test in spatial frequencies of 1.5, 3.0,6.0, 12.0, 18.0 cycles per degree (c/d), pattern electroretinograms (PERG) and best corrected visual acuity (BCVA) assay. The analysis of RNFL thickness in each group was performed at four preset locations of the optic disc (i.e., temporally, superiorly, nasally, and inferiorly). To assess the structure-function relationship, the BCVA,contrast sensitivity, PERG-P50 amplitude and latency to optic RNFL thickness at each quadrant were analyzed in both NPDR and NRD groups. RESULTS: The RNFL thickness at four preset locations of the optic disc (meanly, nasally, temporally, superiorly, and inferiorly) were (97.7 ± 13.0), (71.7 ± 10.3), (70.9 ± 13.3), (118.3 ± 19.7), and (123.1 ± 20.8) µm in the NPDR group; (98.6 ± 15.3), (74.8 ± 13.1), (71.8 ± 14.6), (119.5 ± 17.2), and (125.6 ± 19.9) µm in the NRD group;and (99.1 ± 11.8), (77.4 ± 12.6), (72.6 ± 13.2), (119.1 ± 18.1), and (127.1 ± 19.3) µm in the normal group. The nasally optic RNFL thickness was significantly different among the three groups (F = 8.56, P = 0.000). The thickness in the NPDR and in the NRD group were significantly thinner than that in the normal group (SNK-q test:q = 3.16, 3.11, respectively; both P < 0.05). In the NPDR group, the nasally optic RNFL thickness was significantly thinner than that in the NRD group (SNK-q test:q = 3.07, P < 0.05). The inferiorly optic RNFL thickness was also significantly different among the three groups (F = 3.841, P = 0.035). The thickness in the NPDR group was significantly thinner than that in the normal group (SNK-q test:q = 3.090, P < 0.05). Yet, the difference of inferiorly optic RNFL thickness between the NRD group and the normal or the NPDR group did not reach the level of statistical significance (SNK-q test:q = 2.101, 1.955, P > 0.05). The temporally or superiorly optic RNFL thickness,or the average thickness of optic RNFL did not differ significantly among the three groups (F = 0.985, P = 0.375; F = 0.333, P = 0.71; F = 0.975, P = 0.379, respectively). Contrast sensitivities (1.5, 3.0,6.0, 12.0, 18.0 c/d), PERG-P50 amplitude and latency were all significantly correlated with the RNFL thickness of the nasal quadrant (nasal = 0.28, 0.26, 0.3, 0.25, 0.45, 0.65, 0.48, respectively; P < 0.05) and the inferior quadrant (inferior = 0.25, 0.28, 0.27, 0.26, 0.28, 0.37, 0.71; P < 0.05) in the NPDR group. Contrast sensitivities in high spatial frequencies (6.0, 12.0, 18.0 c/d), PERG-P50 amplitude were also significantly correlated with the RNFL thickness of the nasal quadrant (nasal = 0.59, 0.45, 0.66, 0.33, respectively; P < 0.05) and the inferior quadrant (inferior = 0.46, 0.71, 0.52, 0.41, respectively; P < 0.05) in the NRD group. CONCLUSION: The optic RNFL thickness of the nasal and inferior quadrant have been already reduced in patients with NPRD and are significantly correlated with the change of vision function.

[The effect of OPTC-shRNA on the bovine retinal pigment epithelial cells and hyalocytes co-culture collagen gel contraction system].

OBJECTIVE: To investigate the OPTC-shRNA inhibiting effect on the opticin expression by the bovine hyalocytes and retina pigment epithelial (RPE) cells co-culture collagen gel contraction system. METHODS: Experimental study. The OPTC-shRNA expression vector was designed and transfected into bovine RPE cells cultured in vitro. The relative expression and the inhibition rate of the opticin protein were measured by Western blot on days 3, 5 and 7. An in vitro cells co-culture bovine type I collagen gel contraction assay was constructed consisting of the hyalocytes and RPE cells. Six groups were established in this experiments:OPTC-shRNA plasmid transfected RPE cells and hyalocytes (group A), empty plasmid transfected RPE cells and hyalocytes (group B), non-transfected RPE cells and hyalocytes (group C), non-transfected RPE cells (group D), only hyalocytes (group E), and no cells (group F). The collagen gel contractile activities of these groups were compared by One-way ANOVA, SNK-q tests and regression analysis;and the influence of the hyalocytes density variance on the collagen gel contraction in groups A, B and C were also analyzed. RESULTS: The OPTC-shRNA expression vector with significant inhibition effect was constructed and transfected into bovine RPE cells successfully. The results of Western blot analysis showed that the inhibitory rates on the opticin expression on days 3, 5 and 7 were (83.91 ± 2.88), (84.71 ± 4.27) and (82.85 ± 2.72)%, respectively. Furthermore, the differences among days 3, 5 and 7 were insignificant (F = 1.15, P > 0.05). On day 3, the gel contraction rates for the sub-groups with various hyalocytes densities (2×10(7), 1×10(8) and 5×10(8)/L) in groups A, B and C were: group A: (23.52 ± 2.08), (56.00 ± 1.02), (61.62 ± 1.73)%; group B: (16.56 ± 2.01), (36.41 ± 1.33), (49.56 ± 1.75)%; group C: (15.75 ± 1.37), (37.45 ± 1.14), (48.45 ± 1.97)%. The gel contraction rates for groups D and E were (12.18 ± 0.95)% and (10.95 ± 0.93)%, respectively; no gel contraction was observed in group F. Pairwise comparisons of the gel contraction rates were performed by SNK-q test among groups A, B and C for various hyalocyte densities. In the 2×10(7)/L cell density group, the differences between groups A and B or C were significant (q = 11.38, 2.72, respectively, P both < 0.05), the differences between B and C were insignificant (q = 1.34, P > 0.05). In the 1×10(8)/L cell density group, the differences between groups A and B or C were significant (q = 8.83, 46.22, respectively, P both < 0.05), the differences between B and C were insignificant (q = 1.34, P > 0.05). In the 5×10(8)/L cell density group, the differences between groups A and B or C were significant (q = 48.83, 46.22, respectively, P both < 0.05), the differences between groups B and C were insignificant (q = 1.74, P > 0.05). Pairwise comparisons of the sub-groups with different hyalocyte densities in groups A, B and C (comparisons of 2×10(7)/L and 1×10(8)/L, 2×10(7)/L and 5×10(8)/L, 2×10(7)/L and 2×10(7)/L, respectively), the differences were all significant (group A:q = -55.97, -65.66, -9.69, respectively; group B: q = -34.53, -57.41, -22.88, respectively; group C: q = -41.94, -63.19, -21.25, P all < 0.05). Furthermore, the regression analysis was performed between the hyalocyte density and the collage gel contraction rates in each group. The results showed that there was a positive correlation between the gel contraction rates of the co-culture collagen gel contraction system and its hyalocyte density (groups A, B, C: r = 0.919, 0.981, 0.937, respectively, P all < 0.05). Pairwise comparison of groups D and E, D and F, E and F by SNK-q test revealed q = 54.87, 49.33, 5.54, respectively, P all < 0.05. CONCLUSION: Opticin is capable of regulating the contraction of bovine hyalocytes and RPE cells co-culture collagen gel.

Pneumatic Retinopexy Involving the Use of Intravitreal Air Injection and Laser Photocoagulation for Rhegmatogenous Retinal Detachment in Phakic Eyes.

The clinical efficacy of pneumatic retinopexy (PR) using intravitreal pure air injection and laser photocoagulation for rhegmatogenous retinal detachment (RRD) remains unknown. Thirty-nine consecutive patients with RRD (39 eyes) were included in this prospective case series. All patients underwent two-step PR surgery containing pure air intravitreal injection and laser photocoagulation retinopexy during hospitalization. The main outcomes were best-corrected visual acuity (BCVA) and primary anatomic success rates after PR treatment. The mean follow-up was 18.3 ± 9.7 months, ranging from 6 to 37 months. The primary anatomic success rate was 89.7% (35/39) after PR treatment. Final reattachment of the retina was achieved in 100% of cases. Macular epiretinal membrane was developed in two patients (5.7%) among successful PR cases during the follow-up. The mean logMAR BCVA value was significantly improved from 0.94 ± 0.69 before surgery to 0.39 ± 0.41 after surgery. The average central retinal thickness was significantly thinner in the RRD eyes of macula-off patients (206.8 ± 56.13 µm) when compared with the fellow eyes (234.6 ± 48.4 µm) at the last follow-up (p = 0.005). This study concluded that an inpatient PR procedure with pure air injection and laser photocoagulation is a safe and effective approach to treating patients with RRD, who may achieve a high single-operation success rate and good visual acuity recovery.

Artificial intelligence-aided diagnosis and treatment in the field of optometry.

With the rapid development of computer technology, the application of artificial intelligence (AI) to ophthalmology has gained prominence in modern medicine. As modern optometry is closely related to ophthalmology, AI research on optometry has also increased. This review summarizes current AI research and technologies used for diagnosis in optometry, related to myopia, strabismus, amblyopia, optical glasses, contact lenses, and other aspects. The aim is to identify mature AI models that are suitable for research on optometry and potential algorithms that may be used in future clinical practice.

Functional OCT angiography reveals early retinal neurovascular dysfunction in diabetes with capillary resolution.

Altered retinal neurovascular coupling may contribute to the development and progression of diabetic retinopathy (DR) but remains highly challenging to measure due to limited resolution and field of view of the existing functional hyperemia imaging. Here, we present a novel modality of functional OCT angiography (fOCTA) that allows a 3D imaging of retinal functional hyperemia across the entire vascular tree with single-capillary resolution. In fOCTA, functional hyperemia was evoked by a flicker light stimulation, recorded by a synchronized time-lapse OCTA (i.e., 4D), and extracted precisely from each capillary segment (space) and stimulation period (time) in the OCTA time series. The high-resolution fOCTA revealed that the retinal capillaries, particularly the intermediate capillary plexus, exhibited apparent hyperemic response in normal mice, and significant functional hyperemia loss (P < 0.001) at an early stage of DR with few overt signs of retinopathy and visible restoration after aminoguanidine treatment (P < 0.05). Retinal capillary functional hyperemia has strong potential to provide sensitive biomarkers of early DR, and retinal fOCTA would provide new insights into the pathophysiology, screening and treatment of early DR.

Regulation of cell-mediated collagen gel contraction in human retinal pigment epithelium cells by vascular endothelial growth factor compared with transforming growth factor-ß2.

BACKGROUND: To explore the potential role of vascular endothelial growth factor compared with transforming growth factor-ß2 in the regulation of human retinal pigment epithelium cell-mediated collagen gel contraction. METHODS: The retinal pigment epithelium cell mediated type I collagen gel contraction assay was performed to evaluate and compare the effect of vascular endothelial growth factor and transforming growth factor-ß2. The number of viable retinal pigment epithelium cells in the gel and the expression of α-smooth muscle actin were analysed. RESULTS: Both vascular endothelial growth factor and transforming growth factor-ß2 caused a time dependent gel contraction, associated with over expression of α-smooth muscle actin in retinal pigment epithelium cells undergoing a fibroblast like transformation. The decrease in volume of the collagen gel and increase in α-smooth muscle actin expression were more significant in the transforming growth factor-ß2-treated group than in vascular endothelial growth factor-treated group beginning at day 2, and the growth of retinal pigment epithelium cells was significantly more inhibited in the transforming growth factor-ß2-treated group compared with the vascular endothelial growth factor-treated group after day 1 (P < 0.05). Transforming growth factor-ß2 stimulation increased both vascular endothelial growth factor mRNA expression and secretion. The α-smooth muscle actin expression and the change in volume of collagen gel were significantly positively correlated in both experimental groups. CONCLUSIONS: Both vascular endothelial growth factor and transforming growth factor-ß2 can cause induction of retinal pigment epithelium cell-mediated collagen gel contraction in vitro via partial upregulation of α-smooth muscle actin expression.

[Critical role and involvement of vascular endothelial growth factor and transforming growth factor-ß2 in collagen gel contraction induced by retinal pigment epithelial cells].

OBJECTIVE: To investigate the influence of vascular endothelial growth factor(VEGF) and transforming growth factor (TGF)-ß(2) to human retinal pigment epithelium(RPE) cell differentiation, and the mechanism of collagen gel contraction mediated by RPE cells. METHODS: Experiment study. An in vitro collagen gel contraction assay was performed to evaluate the effect of cultured human RPE in addition of VEGF and TGF-ß(2) at indicated time points (24 h, 48 h and 72 h). Three groups were established in the experiment:control group, 50 µg/L VEGF group and 5 µg/L TGF-ß(2) group. The effects of both cytokines on the collagen gel contraction were analyzed by the reduced diameter of the collagen gel. And the changes of cell morphology and their transdifferentiation were assessed to estimate the possible connection between RPE transdifferentiation and collagen gel contraction. One-way ANOVA was used in conjunction with SNK-q test to assess statistical significance at different time periods within groups. RESULTS: There were differences on collagen gel contraction rates among VEGF group [(34.7 ± 3.1)%, (44.3 ± 6.0)%, (44.0 ± 7.2)%], TGF-ß(2) group [(29.3 ± 3.1)%, (31.7 ± 3.5)%, (29.0 ± 3.6)%] and control group [(20.0 ± 0.5)%, (17.3 ± 3.6)%, (19.1 ± 0.8)%] at 24 h, 48 h and 72 h after cultured (24 h: F = 26.220, P = 0.001; 48 h: F = 26.796, P = 0.001; 72 h: F = 21.522, P = 0.002), and on each time point two two comparison in the three groups (SNK-q test, P < 0.05). There were differences on protein expression level of α-smooth muscle actin (α-SMA) in 50 µg/L VEGF group and 5 µg/L TGF-ß(2) group at difference time points, respectively (TGF-ß(2) group: F = 1.134, P = 0.000; each time point: SNK-q test, P < 0.05; VEGF group: F = 279.179, P = 0.000; each time point: SNK-q test, P < 0.05). Moreover, TGF-ß(2) (5 µg/L) demonstrated stronger and more permanent gel contraction than VEGF (50 µg/L) (6 h: F = 3.646, P = 0.000; 24 h: F = 18.706, P = 0.003; 48 h: F = 124.195, P = 0.000; 72 h: F = 76.811, P = 0.000). RPE cells' form happened fibroblasts sample transformation in both VEGF group and TGF-ß(2) group. CONCLUSIONS: Both VEGF and TGF-ß(2) can induce the collagen gel contraction, partly by means of inducing the expression of α-SMA and RPE contraction, which may thus contribute to the explanations of vitro-retinal diseases.

[Spectral domain optical coherence tomography to assess the association between the inner caliber of large retinal vessel and the primary hypertension].

OBJECTIVE: To assess the inner caliber of large retinal vessel quantitatively using spectral domain optical coherence tomography (SD-OCT) and to reveal the association between changes in the inner caliber of large retinal vessel and the primary hypertension. METHODS: A retrospective case-control study was carried out including 215 cases (with primary hypertension) and 210 controls (without primary hypertension) admitted to our hospital since 2009 and all the cases and controls were grouped according to age. SD-OCT was performed to assess the inner caliber of large retinal vessel quantitatively including retinal artery inner caliber (RAIC), retinal vein inner caliber (RVIC) and retinal arterio-venous inner caliber ratio (RAVICR). The differences in the inner caliber of large retinal vessel between the cases and the controls in each age groups were analyzed by t test. In all cases, multiple comparisons were performed according to their blood pressure level by SNK test of one way ANOVA. The RAVICR was also correlated with the following relevant determinants via multiple stepwise regression analysis: age, diastolic and systolic blood pressure. RESULTS: In each age group of cases (< 40, 40 to 49, 50 to 59, 60 to 69, ≥ 70 years), the values of RAIC were (93.0 ± 6.3), (86.2 ± 6.1), (84.5 ± 5.1), (84.0 ± 5.5), and (81.7 ± 5.4) µm respectively, and the values of RVIC were (129.4 ± 5.8), (130.7 ± 6.5), (129.6 ± 5.4), (132.2 ± 6.4), and (131.6 ± 5.1) µm respectively, and the values of RAVICR were (0.720 ± 0.07), (0.661 ± 0.06), (0.653 ± 0.04), (0.637 ± 0.06), and (0.621 ± 0.05) µm respectively. Compared with controls, RAIC (t = -4.813, -10.893, -15.689, -8.811, and -10.151 respectively; P < 0.05) and RAVICR (t = -3.276, -8.654, -13.470, -7.801, and -9.210 respectively; P < 0.05) were significantly decreased in each age group of cases. Multiple comparisons were made among each systolic and diastolic pressure groups in all cases. In systolic groups, difference of RAIC or RAVICR were significant (SNK test)between 140 to 149 mm Hg (1 mm Hg = 0.133 kPa) and 170 to 179 mm Hg group (q = 9.46, 10.61; P < 0.05), 140 to 149 mm Hg and ≥ 180 mm Hg group (q = 11.03, 13.98; P < 0.05), 150 to 159 mm Hg and 170 to 179 mm Hg group (q = 8.13, 8.82; P < 0.05), 150 to 159 mm Hg group and ≥ 180 mm Hg group (q = 9.01, 9.97; P < 0.05). In diastolic groups, difference of RAIC or RAVICR were significant (SNK test) between 90 to 99 mm Hg and 100 to 109 mm Hg group (q = 6.79, 5.95;P < 0.05), 90 to 99 mm Hg and ≥ 110 mm Hg group (q = 9.72, 10.21; P < 0.05), 100 to 109 mm Hg and ≥ 110 mm Hg group (q = 5.93, 6.07; P < 0.05). RAVICR was associated with the diastolic and systolic blood pressure revealed by the multiple stepwise regression analysis (ANOVA: F = 11.231; Standardized regression coefficient: ß = -0.024, -0.019, respectively; P < 0.05). CONCLUSIONS: Quantitative assessment for the inner caliber of large retinal vessel can be done by SD-OCT. The value of RAI and RAVICR were correlated with diastolic and systolic blood pressure in primary hypertension.

Dynamic inverse SNR-decorrelation OCT angiography with GPU acceleration.

Dynamic OCT angiography (OCTA) is an attractive approach for monitoring stimulus-evoked hemodynamics; however, a 4D (3D space and time) dataset requires a long acquisition time and has a large data size, thereby posing a great challenge to data processing. This study proposed a GPU-based real-time data processing pipeline for dynamic inverse SNR-decorrelation OCTA (ID-OCTA), offering a measured line-process rate of 133 kHz for displaying OCT and OCTA cross-sections in real time. Real-time processing enabled automatic optimization of angiogram quality, which improved the vessel SNR, contrast-to-noise ratio, and connectivity by 14.37, 14.08, and 9.76%, respectively. Furthermore, motion-contrast 4D angiographic imaging of stimulus-evoked hemodynamics was achieved within a single trail in the mouse retina. Consequently, a flicker light stimulus evoked an apparent dilation of the retinal arterioles and venules and an elevation of the decorrelation value in the retinal plexuses. Therefore, GPU ID-OCTA enables real-time and high-quality angiographic imaging and is particularly suitable for hemodynamic studies.

[The effect of vascular endothelial growth factor and hypoxia on the secretion of opticin in retinal pigment epithelium cells].

OBJECTIVE: To evaluate the role of vascular endothelial growth factor or hypoxia on the secretion of opticin in retinal pigment epithelium cells. METHODS: Human RPE cells were cultured, the third to sixth passage of retinal pigment epithelium (RPE) cells were placed in 6-well culture plates at a density of 4 × 10(4)/well. For hypoxia experiment, the cells were cultured under hypoxic condition for different times. For vascular endothelial growth factor (VEGF) experiment, the media was changed to DMEM containing different concentration VEGF (1, 10, 50, 100 µg/L) for 24 h respectively. VEGF mRNA levels were determined by RT-RCR method. The protein content of opticin in RPE cells or culture media was detected by Western blot. Matrix metalloproteinase activity in culture media was analysis by zymography. One way ANOVA was used to test the comparisons between experimental groups and control group. RESULTS: Western blot experiment showed the opticin expression was not changed in RPE cells after hypoxia treatment, however was significantly decreased in culture media. Compared with control group (0.21 ± 0.03). The relative density of VEGF mRNA levels (0.81 ± 0.04, 0.67 ± 0.07) in RPE cells were increased after 12 h or 24 h hypoxia treatment (F = 483.60, P < 0.05). Opticin expression in RPE cells was also remain unchanged after vary concentration VEGF addition treatment (F = 2.16, P > 0.05), the relative density of opticin expression in VEGF conditioned culture medium were 0.65 ± 0.02, 0.52 ± 0.04, 0.23 ± 0.03, 0.30 ± 0.03 respectively, and the difference in culture media was significant compared to control group (0.73 ± 0.04) (F = 141.38, P < 0.05). Zymography indicate a matrix metalloproteinases type 2 digest band, the activities were enhanced with VEGF increasing. The decrease of opticin in culture media after VEGF treatment could be inhibited by low condition of EDTA. CONCLUSION: VEGF and hypoxia have an effect on the on the secretion of opiticin in RPE cells, it may be contributed to the increasing levels of matrix metalloproteinases type 2.

Noninvasive OCT angiography-based blood attenuation measurements correlate with blood glucose level in the mouse retina.

In this study, we investigated the correlation of the blood optical attenuation coefficient (OAC) and the blood glucose concentration (BGC). The blood OAC was measured in mouse retina in vivo by analyzing the depth attenuation of backscattered light under the guidance of OCT angiography (OCTA) vascular mapping, and then its correlation to the BGC was further investigated. The optical attenuation of the blood components presented a more reliable correlation to BGC than that of the background tissues. The arteries and veins presented a blood OAC change of ∼0.05-0.07 mm-1 per 10 mg/dl and a significant (P < 0.001) elevation of blood OAC in diabetic mice was observed. Furthermore, different kinds of vessels also presented different performances. The veins had a higher correlation coefficient (R=0.86) between the measured blood OAC and BGC than that of the arteries (R=0.73). Besides, the blood OAC changes of the specific vessels occur without any obvious change in the vascular morphology in the retina. The blood OAC-BGC correlation suggests a concept of non-invasive OCTA-based glucometry, allowing a fast assessment of the blood glucose of specific vessels with superior motion immunity. A direct glucometry of the retina would be helpful for accurately monitoring the progression of diabetic retinopathy.

Optical Coherence Tomography Angiography-Based Quantitative Assessment of Morphologic Changes in Active Myopic Choroidal Neovascularization During Anti-vascular Endothelial Growth Factor Therapy.

Purpose: To establish quantitative profile of the morphologic changes among patients with active myopic choroidal neovascularization (mCNV) before and after anti-vascular endothelial growth factor (VEGF) therapy using optical coherence tomography angiography (OCTA) to assess the therapeutic response. Methods: Patients with active mCNV who received anti-VEGF injections between February 2017 to October 2020 and fit the study criteria were retrospectively reviewed. Quantitative analysis of their OCTA images were carried out to evaluate the morphologic features and vascular changes of mCNV lesions in response to anti-VEGF therapy. For further quantitative profiling, mCNV area, fractal dimension, vessel area, vessel density, vessel diameter, vessel length, vessel junction, junction density, and vessel tortuosity were obtained by means of advanced skeletonization postprocessing analyses. Results: Thirty-one eyes of 29 consecutive patients with OCTA-positive mCNV lesions (mean spherical equivalent: -12.55 ± 3.24 diopters) were included. The 31 cases were divided into two phenotypes at baseline: organized interlacing pattern (83.87%) and disorganized vascular loops pattern (16.13%). The values of mCNV area, fractal dimension, vessel area, vessel length, vessel junction, and junction density decreased remarkably 1 month after the initial anti-VEGF injection (p < 0.001). Although, vessel density, vessel diameter, and vessel tortuosity increased meanwhile, only vessel diameter displayed statistical significance (p = 0.027). Of note, relative ratio analysis showed that vessel junction was the most sensitive biomarker in response to anti-VEGF therapy, reflecting a mean decrease of 50.36%. Sensitivity lowered successively in biomarkers of vessel length, vessel area, junction density, mCNV area, and fractal dimension. In addition, percent change of mCNV area (r = 0.552, p = 0.002), fractal dimension (r = 0.446, p = 0.017), vessel area (r = 0.518, p = 0.005), and vessel length (r = 0.440, p = 0.019) were moderately associated with that of central retinal thickness. Conclusions: The study showed morphological as well as quantitative changes on OCTA responding to anti-VEGF treatment in mCNV patients, among which vessel junctions might be the most predictive biomarker. OCTA-based analysis, providing intuitive images and a large spectrum of quantitative data at the same time, could promote new insights into the therapeutic response assessment in mCNV patients.

Effect of an intravitreal injection of bevacizumab on the expression of VEGF and CD34 in the retina of diabetic rats.

PURPOSE: To evaluate the efficacy of intravitreal injection of bevacizumab as a preventive intervention of vascular endothelial cell proliferation in the retina of diabetic rats. METHODS: Fifty-four streptozotocin-induced diabetic Wistar rats were injected intravitreally with 3 µL (25 mg/mL) of bevacizumab into left eyes and 3 µL of saline into the right eyes. Immunohistochemistry and enzyme-linked immunosorbent assays for CD34 and VEGF were used to assess retinal angiogenesis, and transmission electron microscopy was used to evaluate the ultrastructure of retinal capillaries. RESULTS: Retinal expression of VEGF was inhibited 1 week and 1 month after injection (P < 0.01, paired t-test), and the expression of CD34 was not obviously inhibited until 2 months after injection (P < 0.05, paired t-test). Using multiple comparisons between the left eyes of bevacizumab-treated rats, the VEGF expression before injection was higher than at 1 week or 1 month after injection (P < 0.05, Dunnett's t-test), and similar to 2 months after injection (P > 0.05, Dunnett's t-test). The amount of VEGF expression was higher 2 months after injection than 1 week or 1 month after injection, and also higher 1 week after injection compared with 1 month after injection (P < 0.05, Student-Newman-Keuls test). CD34 expression decreased more significantly 2 months after injection compared with before injection, 1 week or 1 month after injection (P < 0.05, Dunnett's t-test). CONCLUSION: A single intraocular injection of bevacizumab may be beneficial as a therapy for preventing retinal vascular endothelial cell growth in the eyes of diabetic rats.

A biomimetic tarso-conjunctival biphasic scaffold for eyelid reconstruction in vivo.

Conventional 3D porous scaffolds used as tarsal plate substitute may cause corneal irritation and conjunctival mucoid discharge, and even lead to blindness and cicatricial blepharon deformities. In this study, collagen/chitosan (Col/CS) sponges with thickness of 240 µm, 466 µm, and 724 µm were composited onto poly(propylene fumarate)-co-2-hydroxyethyl methacrylate (PPF-HEMA) polymer networks to obtain the corresponding biphasic scaffolds, which simulate the natural anatomy of posterior lamella of eyelid. These three scaffolds exhibited a porous structure with porosity of ∼90%, simulated elastic modulus, appropriate degradation rate and good biocompatibility. Composited with Col/CS sponge of difference thickness, the scaffolds induced different cellular behaviors such as proliferation, distribution and stratification, by regulating the mechanical properties cells sensed as effective modulus. In a rabbit tarso-conjunctival defect model, the grafted biphasic scaffolds promoted re-epithelization with functional regenerated conjunctiva. Hence, the biphasic composite scaffolds may be a promising substitute for tarso-conjunctival repair.

Changes of corneal tomography in patients with congenital blepharoptosis.

The study aimed to evaluate the effect of drooped eyelid on corneal tomography in congenital blepharoptosis patients. Sixty-four patients with congenital blepharoptosis and 64 age- and sex- matched healthy subjects were included. According to the eyelid margin to corneal light reflex distance (MRD), eyes with congenital blepharoptosis were categorized as mild, moderate, or severe. The eyes were scanned using the rotating Scheimpflug camera. Increased topometric parameters were observed in moderate and severe blepharoptosis. Back corneal elevations at the thinnest point were significant higher for mild (P = 0.009), moderate (P < 0.001), and severe (P < 0.001) congenital blepharoptosis compared with controls. Maximum Ambrósio's relational thickness (ART) was decreased in eyes with severe blepharoptosis (P < 0.001). Fnal D values were significantly higher in moderate (P < 0.001) and severe blepharoptosis (P < 0.001) groups than that of controls. There were significant correlations between MRD and most corneal tomographic parameters. Our findings indicated there was a trend toward subclinical keratoconus-like changes in the corneas of congenital blepharoptosis, with the increase of ptosis severity.