Corneal Keratocyte Density and Corneal Nerves Are Reduced in Patients With Severe Obesity and Improve After Bariatric Surgery

PurposeObesity is associated with peripheral neuropathy, which bariatric surgery may ameliorate. The aim of this study was to assess whether corneal confocal microscopy can show a change in corneal nerve morphology and keratocyte density in subjects with severe obesity after bariatric surgery.MethodsTwenty obese patients with diabetes (n = 13) and without diabetes (n = 7) underwent assessment of hemoglobin A1c (HbA1c), lipids, IL-6, highly sensitive C-reactive protein (hsCRP), and corneal confocal microscopy before and 12 months after bariatric surgery. Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and keratocyte density (KD) from the anterior, middle, and posterior stroma were quantified. Twenty-two controls underwent assessment at baseline only.ResultsCNFL (P < 0.001), CNBD (P < 0.05), and anterior (P < 0.001), middle (P < 0.001), and posterior (P < 0.001) keratocyte densities were significantly lower in obese patients compared to controls, and anterior keratocyte density (AKD) correlated with CNFL. Twelve months after bariatric surgery, there were significant improvements in body mass index (BMI; P < 0.001), HDL cholesterol (P < 0.05), hsCRP (P < 0.001), and IL-6 (P < 0.01). There were significant increases in CNFD (P < 0.05), CNBD (P < 0.05), CNFL (P < 0.05), and anterior (P < 0.05) and middle (P < 0.001) keratocyte densities. The increase in AKD correlated with a decrease in BMI (r = –0.55, P < 0.05) and triglycerides (r = –0.85, P < 0.001). There were no significant correlations between the change in keratocyte densities and corneal nerve fiber or other neuropathy measures.ConclusionsCorneal confocal microscopy demonstrates early small fiber damage and reduced keratocyte density in obese patients. Bariatric surgery leads to weight reduction and improvement in lipids and inflammation and an improvement in keratocyte density and corneal nerve regeneration.     

Protective effects of piperine on the retina of mice with streptozotocin-induced diabetes by suppressing HIF-1/VEGFA pathway and promoting PEDF expression

AIM: To evaluate the protective mechanisms of piperine in the retina of mice with streptozotocin-induced diabetes. METHODS: In experiments in vitro, stimulation by chemical hypoxia was established in ARPE-19 cells. Then, the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA), and pigment epithelium-derived factor (PEDF) was assessed at the mRNA and protein levels. In experiments in vivo, diabetes mellitus was established by intraperitoneally injecting 150 mg/kg streptozotocin once. After 3wk of the onset of diabetes, 15 mg/kg piperine was intraperitoneally injected once daily for 1 or 3wk. Then, the retinal morphology and mRNA and protein expression were assessed. RESULTS: In hypoxia, 1-100 μmol/L piperine significantly decreased the expression of VEGFA mRNA and increased the expression of PEDF mRNA without affecting HIF-1α mRNA. Meanwhile, 100 μmol/L piperine substantially decreased the protein level of VEGFA and increased the protein level of PEDF. The HIF-1α protein level was also hampered by piperine. In the diabetic retina of mice, the morphological damage was alleviated by piperine. Likewise, the retinal vascular leakage was substantially decreased by piperine. Further, the protein levels of HIF-1α and VEGFA were significantly reduced by piperine. Moreover, the level of the antiangiogenic factor of PEDF dramatically increased by piperine. CONCLUSION: Piperine may exert protective effects on the retina of mice with diabetes via regulating the pro-antiangiogenic homeostasis composed of HIF-1/VEGFA and PEDF.     

圆锥角膜基底下神经与角膜形态的相关性研究

目的 研究圆锥角膜（KC）基底下神经与角膜形态的相关性。设计 前瞻性比较性病例系列。研究对象 2018年3月至2019年3月北京同仁医院KC患者（KC组）74例74眼,KC顿挫期组25例25眼,正常对照组24例24眼。方法 通过眼部检查及Pentacam眼前节分析仪诊断KC、KC顿挫期及正常角膜。角膜形态参数采用Pentacam的角膜最大曲率值（Kmax）和角膜最薄厚度值（Minpachy）。应用ACCmetrics软件计算由活体激光共聚焦显微镜（IVCM）获得的基底下神经图片上六种基底下神经参数：角膜神经纤维密度（CNFD）、角膜神经分支密度（CNBD）、角膜神经纤维长度（CNFL）、角膜总分支密度（CTBD）、角膜神经纤维面积（CNFA）、角膜神经纤维宽度（CNFW）。分析KC组角膜基底下神经与角膜形态的相关性,并比较各两组间角膜基底下神经参数的差异。主要指标 Kmax、Minpachy、CNFD、CNBD、CNFL、CTBD、CNFA、CNFW。结果 IVCM定性分析观察到KC组角膜基底下神经迂曲度增加、基底下神经纤维密度明显低,偶可见神经呈束状排列。KC组和正常对照组比较,CNFD、CNBD、CNFL和CNFW差异均有统计学意义（P均<0.05）。KC组和顿挫组比较,CNFL和CNFA差异均有统计学意义（P均<0.05）。顿挫组和正常对照组比较,CNFD和CNFL差异均有统计学意义（P均<0.05）。KC组CNFD、CNFL和CNFW分别与Kmax具有相关性（P=0.001、0.001和0.006）, KC组的CNFD、CNBD、CNFL和CNFW分别与Minpachy具有相关性（P=0.01、0.01、0.004和0.02）。结论 KC患者角膜基底下神经的改变可能早于角膜形态的改变,基底下神经随着疾病的进展而变化。CNFD和CNFL可能是诊断早期圆锥角膜的指标。（眼科, 2020, 29： 118-122）     

白内障手术不同方向角膜切口对术后泪膜稳定性及角膜神经损伤修复的影响

目的：分析白内障超声乳化术不同方向的透明角膜切口对年龄相关性白内障（ARC）及糖尿病性白内障（DC）患者泪膜稳定性及角膜神经损伤修复的影响。方法：前瞻性研究。收集2021年9—12月常州市第三人民医院眼科行超声乳化吸除联合人工晶状体（IOL）植入术的白内障患者67例（80眼）,其中ARC患者35例（40眼）,DC患者32例（40眼）。ARC患者按随机数字表法分为2组：Ⅰ组18例（20 眼）行上方透明角膜切口;Ⅱ组17例（20眼）行颞侧透明角膜切口。DC患者按随机数字表法分为2 组：Ⅲ组16例（20眼）行上方透明角膜切口;Ⅳ组16例（20眼）行颞侧透明角膜切口。术前,术后1 周、1个月及3个月时行泪膜破裂时间（BUT）、泪河高度（TMH）、泪液分泌试验Ⅰ（SⅠT）检查;术后1周、1个月及3个月时行眼前节光学相干断层成像扫描（AS-OCT）检查;术后1个月及3个月时行角膜共焦显微镜（CCM）检查。各组术后BUT、TMH、SⅠT与术前比较采用t检验;角膜神经纤维主干密度（CNFD）、角膜神经纤维分支密度（CNBD）组间比较采用单因素方差分析。角膜神经纤维长度（CNFL）、角膜神经纤维宽度（CNFW）组间比较采用非参数Mann-Whitney检验。结果：术后l周、1个月,4组患者BUT、TMH、SⅠT与术前相比差异均有统计学意义（均P<0.05）。术后1周,Ⅰ组与Ⅲ组相比、Ⅱ组与Ⅳ组相比,BUT、TMH、SⅠT值均较大,差异均有统计学意义（均P<0.05）;术后1 个月时,差异无统计学意义（P>0.05）。术后1个月,所有患者完整的长神经纤维均很少;术后3个月,4组均可见完整长神经纤维且可见神经纤维束连接。与术后1个月相比,术后3个月4组患者CNFL、CNFD、CNBD均升高（均P<0.05）。术后1个月Ⅳ组与Ⅲ组相比,CNFL、CNFD、CNBD均较低（均P<0.05）;术后1、3个月,Ⅰ组与Ⅲ组相比、Ⅱ组与Ⅳ组相比,CNFL、CNFD、CNBD均较高,差异均有统计学意义（均P<0.05）。结论：行白内障手术时,DC患者上方角膜切口对神经的损伤较颞侧切口轻。DC患者眼表泪膜损伤及角膜神经损伤比ARC患者修复慢。     

Biomarkers of in vivo limbal stem cell function

PurposeTo evaluate in vivo parameters as biomarkers of limbal stem cell function and to establish an objective system that detects and stage limbal stem cell deficiency (LSCD).MethodsA total of 126 patients (172 eyes) with LSCD and 67 normal subjects (99 eyes) were included in this observational cross-sectional comparative study. Slit-lamp biomicroscopy, in vivo laser scanning confocal microscopy (IVCM), and anterior segment optical coherence tomography (AS-OCT) were performed to obtain the following: clinical score, cell morphology score, basal cell density (BCD), central corneal epithelial thickness (CET), limbal epithelial thickness (LET), total corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and tortuosity coefficient. Their potential correlations with the severity of LSCD were investigated, and cutoff values were determined.ResultsAn increase clinical score correlated with a decrease in central cornea BCD, limbal BCD, CET, mean LET, maximum LET, CNFL, CNFD, CNBD, and tortuosity coefficient. Regression analyses showed that central cornea BCD, CET and CNFL were the best parameters to differentiate LSCD from normal eyes (Coef = 3.123, 3.379, and 2.223; all p < 0.05). The rank correlation analysis showed a similar outcome between the clinical scores and the central cornea BCD (ρ = 0.79), CET (ρ = 0.82), and CNFL (ρ = 0.71). A comprehensive LSCD grading formula based on a combination of these parameters was established.ConclusionsA comprehensive staging system combining clinical presentation, central cornea BCD, CET, and CNFL is established to accurately and objectively diagnose LSCD and stage its severity.     

DR早期视网膜神经纤维层和角膜神经的变化及其相关性

目的:观察无视网膜微血管病变的糖尿病患者的视网膜神经纤维层(RNFL)和角膜神经纤维(CNF)变化,以及两者变化的相关性.方法:收集40例40眼2型糖尿病患者,经散瞳眼底检查未发现糖尿病视网膜病变,均接受光学相干断层扫描(OCT)检查和活体角膜共聚焦显微镜(IVCM)检查.另收集年龄匹配的80例80眼健康正常眼为对照,分为40例40眼只行OCT检查的RNFL对照组和40例40眼只行IVCM检查的CNF对照组.利用OCT观察视乳头上方、下方、颞侧、鼻侧和平均RNFL厚度,用IVCM观察角膜上皮下角膜神经纤维长度和角膜神经密度.结果:糖尿病组的视乳头上方、颞侧、鼻侧及平均RNFL与对照组比较,差异无统计学意义(P>0.05),但视乳头下方RNFL糖尿病组比RNFL对照组减少,差异有统计学意义(P=0.003).糖尿病组的角膜神经纤维长度、角膜神经密度均比CNF对照组减少(P<0.01).糖尿病组中,平均RNFL与角膜神经纤维长度和角膜神经密度呈正相关(r=0.518,P<0.01;r=0.484,P=0.002),下方RNFL与角膜神经纤维长度和角膜神经密度呈正相关(r=0.607,P<0.01;r=0.573,P<0.01).结论:糖尿病患者在未发现糖尿病视网膜病变前同时存在视网膜神经纤维层和角膜神经的丢失,视网膜神经纤维层变薄主要表现在下方象限,视网膜神经纤维层的变薄与角膜神经的减少呈正相关.     

高度近视行不同激光角膜屈光术后角膜神经纤维的修复情况比较

目的： 探讨高度近视患者行飞秒激光小切口角膜基质透镜取出术（ SMILE）、飞秒激光制瓣的准分子 激光原位角膜磨镶术（ FS-LASIK）以及准分子激光角膜上皮瓣下磨镶术（ LASEK）后早中期角膜各区 域上皮下神经纤维的修复情况。 方法： 前瞻性临床研究。选择2018年6月至2020年12月在青岛大学 附属医院眼科就诊并进行屈光手术矫正的高度近视患者55 例（ 110 眼），按手术方式不同分为SMILE 组22 例（ 44 眼）、 FS-LASIK组18 例（ 36 眼）、 LASEK组15 例（ 30 眼）。各组于术后1、 3、 6 个月行激光 共聚焦显微镜检查，观察角膜各区域神经纤维的修复情况。对术后不同时间各组间的神经纤维各 参数的比较采用随机区组设计的单因素方差分析。 结果： 高度近视患者行SMILE术后早期不同区 域的角膜神经密度、分支密度、长度及宽度较FS-LASIK和LASEK术后更佳，修复速度也更快，较 早达到术前水平。而FS-LASIK术后包括角膜瓣在内的不同区域的角膜神经修复情况居于SMILE和 LASEK之间， LASEK术后早期特别是中央区白色瘢痕样混浊明显，且不同区域的角膜修复速度最慢、 质量最差。术后1 个月， SMILE组和FS-LASIK组术后中央的角膜神经密度（ CNFD）、神经纤维长度 （ CNFL）、神经分叉节点密度（ CTBD）明显优于LASEK组，差异均有统计学意义（均P<0.05）； SMILE 组的主要神经分叉节点密度（ CNBD）明显优于FS-LASIK组和LASEK组（ HSD=4.367， P=0.005； HSD=4.237， P=0.008）。术后3 个月， SMILE组中央CNFD、 CNBD、 CNFL明显优于FS-LASIK和 LASEK组（均P<0.05）； LASEK组神经纤维宽度（CNFW）明显优于SMILE和FS-LASIK组（HSD=3.457， P=0.003； HSD=3.668， P=0.004）。术后6 个月， SMILE组中央CNFD、 CNBD以及CNFL均优于FSLASIK和LASEK组（均P<0.05）。 结论： 高度近视患者行激光角膜屈光术后早中期， SMILE各区域的 神经修复情况较FS-LASIK和LASEK均有显著的领先优势。
     

Impacts of Systemic Hypertension on the Macular Microvasculature in Diabetic Patients Without Clinical Diabetic Retinopathy

PurposeTo identify the impact of hypertension (HTN) on macular microvasculature in type 2 diabetes (T2DM) patients without clinical diabetic retinopathy.MethodsIn this retrospective cross-sectional study, subjects were divided into three groups: controls (control group), patients with T2DM (DM group), and patients with both T2DM and HTN (DM + HTN group). The vessel length density (VD) was compared among the groups. Linear regression analyses were performed to identify factors associated with VD.ResultsThe VD in the control, DM, and DM + HTN groups was 20.43 ± 1.16, 19.50 ± 1.45, and 18.19 ± 2.06 mm⁻¹, respectively (P < 0.001). The best-corrected visual acuity (B = −9.30; P = 0.002), duration of T2DM (B = −0.04; P = 0.020), HTN (B = −0.51; P = 0.016), signal strength (B = 1.12; P < 0.001), and ganglion cell–inner plexiform layer thickness (B = 0.06; P < 0.001) were significant factors affecting VD in patients with T2DM. Additionally, the hemoglobin A1c (HbA1c) (B = −0.49; P = 0.016) was significantly associated with VD in patients with both T2DM and HTN.ConclusionsPatients with T2DM had impaired macular microvasculature, and patients with T2DM with HTN exhibited greater impairment of the microvasculature than did patients with T2DM only. Additionally, physicians should be aware that the macular microvasculature would be more vulnerable to hyperglycemic damage under ischemic conditions by HTN.     

The relationship between corneal subbasal nerve density and corneal sensitivity in patients with Fuchs endothelial corneal dystrophy

Purpose:The aim of this study was to investigate the association between alterations in corneal subbasal nerve plexus and tactile corneal sensitivity in patients with Fuchs’ endothelial corneal dystrophy (FECD).Methods:This retrospective, cross-sectional study included 24 (10 M/14 F) patients with FECD and 25 age- and sex-matched (10 M/15 F) healthy subjects as controls. Subjects with FECD were classified as having early (grades 1 and 2) and late (grades 3 and 4) disease. All subjects underwent central corneal tactile sensitivity measurements with the Cochet–Bonnet esthesiometer (Luneau Ophthalmologie, Chartres, France) and subbasal nerve density evaluation using in vivo confocal microscopy (IVCM). Association between corneal nerve plexus density and corneal sensitivity alterations were evaluated using the Mann–Whitney U test and the Spearman correlation test.Results:Compared to healthy subjects (mean age = 60.4 ± 7.5 years), patients with FECD (mean age = 60.6 ± 8.0 years) had worse central corneal sensitivity scores (5.9 ± 0.1 cm vs. 4.2 ± 0.8 cm; P < 0.001), reduced corneal nerve fibers (3.4 ± 1.3 nerves/frame vs. 5.0 ± 0.9 nerves/frame; P < 0.001) and lower corneal subbasal nerve plexus densities (2229.4 ± 364.3 μm/mm² vs. 1901.6 ± 486.8 μm/mm²; P = 0.050). Patients with late stage FECD demonstrated lower subbasal nerve densities as compared to those with early disease (2204.3 ± 313.1 μm/mm² (range = 1523–2552 μm/mm²); 1397.1 ± 227.4 μm/mm² (range = 1120-1834 μm/mm²); P < 0.001). In the FECD group, subbasal nerve density was found to be directly correlated with corneal sensitivity scores (r = 0.457, P = 0.025).Conclusion:Progressive loss of the corneal subbasal nerve plexus appears to be a consistent feature of FECD. Reduction of the corneal nerve plexus parallels the decrease in corneal sensitivity in this patient population.     

Corneal Nerves Alteration Associated with Corneal Complications after Pars Plana Vitrectomy

PurposeTo evaluate the effect of corneal nerves assessment on predicting corneal complications following pars plana vitrectomy (PPV).MethodsIn this prospective single-center cohort study, 94 patients (94 eyes) received PPV, and were divided into postoperative groups with and without corneal complications. All eyes had corneal nerve fiber length (CNFL), corneal nerve fiber density, and branch density of corneal nerve fibers assessed and calculated with Image J preoperatively. Multivariate logistic regression analysis was used to identify corneal nerve fiber parameters that correlated to post-operative corneal complications. Receiver operator characteristic curve analysis was performed to identify the optimal cut-off point of the corneal fibers’ parameters for predicting corneal complications after PPV.ResultsEleven eyes (11.70%) developed corneal complications at 1 week after PPV. There was significant difference between CNFL (19.44 ± 6.88 vs. 26.84 ± 7.53, p = 0.003), corneal nerve fiber density (28.82 ± 9.91 vs. 37.10 ± 10.16, p = 0.013) and branch density of corneal nerve fibers (55.84 ± 21.08 vs. 82.04 ± 31.89, p = 0.01) in two groups, respectively. Receiver operator characteristic analysis showed that the optimal cutoff value of CNFL to predict corneal complications following PPV was <26.495 mm/mm².ConclusionsThe decrease of CNFL may predict corneal complications following PPV. Regular preoperative corneal confocal microscopy test in PPV patients could be considered.     

Corneal sensitivity and morphology of the corneal subbasal nerve plexus in primary congenital glaucoma

Background

To quantify the corneal subbasal nerve density and the total number of nerve fibers in primary congenital glaucoma (PCG) and to evaluate their impact on corneal sensitivity.

Methods

Forty eyes of 26 PCG patients were compared with 40 eyes randomly selected from 40 non-glaucoma patients who populated the control group. Central corneal sensitivity (CCS) was assessed by means of Cochet–Bonnet esthesiometry. The mean subbasal nerve density and the total number of nerve fibers were quantified by laser-scanning confocal microscopy. Normality of data was assessed by Kolmogorov–Smirnov testing. Differences in parameters were assessed with Student''s t-test, while correlations with CSS were assessed with Pearson''s correlation.

Results

Significant differences were identified in the mean subbasal nerve density (2108±692 μm in PCG, 2642±484 μm in controls, P=0.003) and in the total number of nerve fibers (12.3±4.2 in PCG, 15.4±3.1 in controls, P=0.02). Both groups presented comparable mean CCS and tortuosity. Both groups presented strong correlations between CCS and mean nerve density (r=0.57 in PCG, r=0.67 in controls, all P<0.05), and between CCS and total number of nerve fibers (r=0.55 in PCG, r=0.56 in controls, all P<0.05).

Conclusion

PCG exerts significant changes in both the mean subbasal nerve density and the total number of nerve fibers. However, these changes do not appear to affect central corneal sensitivity.     

Bilateral Limbal Stem Cell Alterations in Patients With Unilateral Herpes Simplex Keratitis and Herpes Zoster Ophthalmicus as Shown by In Vivo Confocal Microscopy

PurposeThe purpose of this study was to investigate the limbal changes in the palisades of Vogt (POV) in patients with herpes simplex keratitis (HSK) and herpes zoster ophthalmicus (HZO) with the application of in vivo confocal microscopy (IVCM).MethodsWe enrolled 35 eyes of 35 consecutive patients with HSK and 4 patients with HZO in this observational study. Thirty-five participants were also recruited from a healthy population as the control group. All subjects were examined by IVCM in addition to routine slit-lamp biomicroscopy. The IVCM images of the corneal basal epithelial cells, corneal nerve, and the corneoscleral limbus were acquired and then were analyzed semiquantitatively.ResultsThe rate of absent and atypical POV was significantly higher in the affected eyes of patients with HSK than in the contralateral eyes and eyes of controls (88.57% vs. 65.71% vs. 17.14%, P < 0.01). In the HZO group, the rate of absent and atypical POV was 100% in the affected eyes and 50% in the contralateral eyes. When compared to the contralateral unaffected eyes and control eyes, the average density of the central basal epithelial cells and the sub-basal nerve plexus density and the total number of nerves in the central area of the affected eyes were significantly lower in the HSK group (1541 ± 704.4 vs. 2510 ± 746.8 vs. 3650 ± 746.1 cells/mm², P < 0.0001). Spearman''s rank correlation showed that the presence of absent and atypical POV had a significant negative correlation with central corneal basal epithelial cells (r_s = −0.44979, P < 0.0001), the density of total nerves (r_s = −0.49742, P < 0.0001), and the total nerve numbers (r_s = −0.48437, P < 0.0001). A significant positive correlation was established between the presence of absent and atypical POV and HSK severity in affected eyes in the superior, inferior, nasal, and temporal quadrants (r_s = 0.68940, r_s = 0.78715, r_s = 0.65591, and r_s = 0.75481, respectively, P < 0.0001) and the contralateral eyes (r_s = 0.51636, r_s = 0.36207, r_s = 0.36990, r_s = 0.51241, correspondingly, P < 0.0001).ConclusionsBoth eyes of patients with unilateral HSK and HZO demonstrated a profound and significant loss of limbal stem cells, which may explain the fact that HSK and HZO are risk factors for limbal stem cell deficiency (LSCD) in both eyes. The loss of LSCs was strongly correlated with the sub-basal nerve plexus and central basal epithelial cell alterations as shown by IVCM.     

Clinical features and surgical outcomes of complications of proliferative diabetic retinopathy in young adults with type 1 diabetes mellitus versus type 2 diabetes mellitus - A comparative observational study

Purpose:To evaluate the clinical profile, visual outcomes, and complications among young adult patients with type 1 diabetes mellitus (insulin-dependent DM-T1DM) in comparison with patients with type 2 diabetes mellitus (T2DM) undergoing vitrectomy for complications of proliferative diabetic retinopathy (PDR).Methods:A retrospective review of patients between 18 and 45 years with T1DM undergoing vitrectomy for complications of PDR between June 2017 and June 2019, with a minimum follow-up of 12 months. Consecutive patients between 30 and 45 years with type 2 diabetes (non-insulin-dependent DM-T2DM) who underwent vitrectomy for the same indications were retrospectively enrolled as the control group.Results:There were 42 eyes (28 patients) in the T1DM group and 58 eyes (47 patients) in the T2DM group. The average age at operation was 35.9 ± 6.88 years and 39.8 ± 3.03 years, respectively (P < 0.001). At the end of follow-up, the mean logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) improved from 1.53 ± 0.55 to 1.30 ± 0.93 (P value 0.07) in the T1DM group and from 1.59 ± 0.46 to 1.00 ± 0.78 in the T2DM group (P = 0.0001). The rate of the primary and final reattachment was 76.2% and 88.1% in the T1DM group and 84.5% and 96.6% in the T2DM group. Preoperative macular tractional retinal detachment (MTRD) and neovascular glaucoma (NVG) in both the groups, chronic kidney disease (CKD) and lack of preoperative Pan retinal photocoagulation (PRP) in the T1DM group, hypertension (HTN) and, resurgery in the T2DM group, were risk factors for poor vision at the final follow-up.Conclusion:The visual and anatomic outcomes were poorer in the T1DM patients which could be due to the longer duration of diabetes with worse glycemic control, associated comorbidities like CKD, and a higher incidence of MTRD.     

Corneal endothelial morphology and central corneal thickness in type 2 diabetes mellitus patients

Purpose:This study aimed to examine the corneal endothelial morphology and thickness in patients with Type 2 diabetes mellitus (T2DM) and compare them with age and sex-matched nondiabetic controls.Methods:This hospital-based cross-sectional observational study was conducted in the ophthalmology department of a tertiary hospital consisting of 262 patients (131 with T2DM as cases and 131 without diabetes who served as controls). All patients underwent a comprehensive ocular examination including visual acuity, slit-lamp biomicroscopy, intraocular pressure measurement. Central corneal thickness (CCT), endothelial cell density (ECD), coefficient of variance (CV), and percentage of hexagonal cells (HEX) were compared between the cases and controls. Predictors of corneal endothelial dysfunctions were analyzed. Data analysis was done by Statistical Package for the Social Sciences (SPSS) version 17.0. Chi-square test, Fisher’s exact test, and Spearman’s rho correlation analysis were used as appropriate.Results:Patients with T2DM showed poorer visual acuity and higher intraocular pressure. As compared to controls, patients with T2DM had thicker CCT, lesser ECD, decreased HEX, and higher CV but the differences were statistically nonsignificant. HbA1c levels showed a significant positive correlation with CCT and CV and a negative correlation with ECD. Macroalbuminuria and higher albumin creatinine ratio was associated with an increase in CV in patients with T2DM.Conclusion:Our study showed that poorly controlled patients with T2DM and those with macroalbuminuria have corneal endothelial abnormalities.     

Elliptical versus circular flap configuration in myopic eyes undergoing femtosecond laser in situ keratomileusis surgery: A contralateral eye study

Purpose:To study whether a customized elliptical flap configuration offers any visual, refractive, or biomechanical advantage over the “conventional” circular flaps in patients undergoing myopic laser in situ keratomileusis (LASIK).Methods:A prospective interventional contralateral eye study was undertaken enrolling 290 eyes of 145 myopic patients (≤−6.0D) undergoing LASIK, wherein the corneal flap was created in one eye using a customized elliptical flap configuration versus a conventional circular flap configuration in the other eye. Postoperatively, we compared the visual outcome, change in higher-order aberrations, corneal asphericity, and corneal biomechanics.Results:The visual outcomes, including higher-order aberrations, were comparable between the two groups. Changes in spherical aberration (mean: 0.234–0.331 versus 0.234–0.42; P = 0.644), corneal asphericity (−0.32–0.34 versus − 0.34–0.45; P = 0.42), corneal hysteresis (9.35–7.33 versus 9.4–6.71, P = 0.489), corneal resistance factor (9.71–7.40 versus 10.38–6.9, P = 0.181) were comparable between the elliptical and circular groups, respectively.Conclusion:We evaluated the usefulness of a customized elliptical flap configuration for performing LASIK surgery. Our data suggests that elliptical flaps may be associated with superior visual and biomechanical performance compared to circular flaps. This is certainly relevant in eyes with “borderline” pre-LASIK profile to improve patient satisfaction and safety after surgery.     

Peripapillary retinal nerve fiber layer thickness in patients with iron deficiency anemia

Purpose:To evaluate the effect of iron deficiency anemia (IDA) on peripapillary retinal nerve fiber layer (RNFL) thickness with optical coherence tomography (OCT).Results:Average ages of 102 patients and 49 control subjects were 35.76 ± 10.112 (range, 18–66) years, and 36.08 ± 8.416 (range, 19–57) years (P = 0.850), respectively. The average RNFL thickness was 94.67 ± 9.380 in the anemia group, and 100.22 ± 9.12 in the control group (P = 0.001). Temporal, nasal, and lower quadrant average RNFL thicknesses of IDA group were thinner than the control group (P = 0.001, P = 0.013, P = 0.008). Upper quadrant RNFL thicknesses in IDA and control groups were similar. Correlation analysis revealed positive correlation between mean RNFL thickness and hemoglobin (r = 0.273), iron (r = 0.177), ferritin (r = 0.163), and transferrin saturations (r = 0.185), while a negative correlation was found between total iron binding capacity (r = −0.199) and mean RNFL thickness.Conclusions:Peripapillary RNFL thickness measured by OCT is thinner in adult female patients with IDA. It may have a significant influence on the management of many disorders such as glaucoma and neuro-ophthalmological diseases.     

Corneal endothelial cells and central corneal thickness in patients with neurofibromatosis type 1

Purpose:The aim of this study was to evaluate the morphological properties of corneal endothelial cells and central corneal thickness (CCT) in patients with neurofibromatosis type 1 (NF1) and to compare them with age-matched healthy controls.Methods:Nineteen NF1 patients and 38 healthy individuals were recruited. All participants underwent complete ophthalmological examination as well as noncontact specular microscopy to measure endothelial cell density (ECD), average cell area (AVG), coefficient of variation of cell area (CV), the percentage of hexagonal cells, and CCT. Eyes with previous ocular trauma, inflammation or surgery, and preexisting corneal and ocular surface diseases were excluded.Results:NF1 patients had higher ECD compared to healthy controls of the same age (2764.2 ± 270.4 versus 2570.4 ± 449.2 cells/mm, respectively), although at a borderline level (P = 0.051). Patients with NF1 presented significantly lower CV and AVG when compared to controls (32.9 ± 4.6 versus 37.8 ± 9.5%, P = 0.011 and 364.9 ± 34.4 versus 406.0 ± 107.4 µm, P = 0.038, respectively). The NF1 group had significantly higher hexagonality in comparison with controls (55.7 ± 6.5 versus 50.5 ± 9.9%, P = 0.025). CCT was similar between the two groups (P = 0.955).Conclusion:Our results show that corneal endothelium has more favorable morphological characteristics in NF1 patients compared to healthy individuals of the same age.     

Corneal nerve fiber loss in diabetes with chronic kidney disease

AimsPatients with chronic kidney disease (CKD) in type 2 diabetes typically manifest with severe peripheral neuropathy. Corneal confocal microscopy is a novel technique that may serve as a marker of nerve injury in peripheral neuropathy. This study examines the changes that occur in corneal nerve morphology as a result of peripheral neuropathy due to renal dysfunction in people with type 2 diabetes.MethodsSixty-two participants (mean age, 62 ± 12 years) with type 2 diabetes and 25 age-matched healthy controls underwent a comprehensive assessment of neuropathy using the total neuropathy score (TNS). The corneal sub-basal nerve plexus was imaged using corneal confocal microscopy. Corneal nerve fiber length, fiber density, branch density, total branch density, nerve fractal dimension, inferior whorl length and inferior whorl nerve fractal dimension were quantified. Based on the eGFR, participants were classified into those with diabetic CKD (eGFR < 60; n = 22) and those without CKD (eGFR ≥ 60; n = 40).ResultsParticipants with diabetic CKD had significantly lower corneal nerve fiber density (P = 0.037), length (P = 0.036) and nerve fractal dimension (P = 0.036) compared to those without CKD. Multiple linear regression analysis revealed that reduced corneal nerve fiber density (ß coefficient = 0.098, P = 0.017), length (ß coefficient = 0.006, P = 0.008) and nerve fractal dimension (ß coefficient = 0.001, P = 0.007) was associated with low eGFR levels when adjusted for age, duration of diabetes and severity of neuropathy.ConclusionCorneal confocal microscopy detects corneal nerve loss in patients with diabetic CKD and reduction in corneal nerve parameters is associated with the decline of kidney function.     

Tear Film Cytokine Profile of Patients With the Boston Keratoprosthesis Type 1: Comparing Patients With and Without Glaucoma

PurposeInflammatory cytokines are involved in glaucoma pathogenesis. The purpose is to compare cytokine levels in the tear film of Boston keratoprosthesis (KPro) patients with and without glaucoma, relative to controls, and correlate levels with clinical parameters.MethodsThis cross-sectional study enrolled 58 eyes (58 patients): 41 KPro eyes with glaucoma, 7 KPro eyes without glaucoma, and 10 healthy controls. Twenty-seven cytokines were measured by multiplex bead immunoassay. Intraocular pressure (IOP), cup-to-disk ratio (CDR), retinal nerve fiber layer, visual acuity, topical medications, and angle closure were assessed in all KPro eyes. Cytokine levels between groups were analyzed by nonparametric tests, and correlations with clinical parameters by Spearman''s test.ResultsLevels of TNF-ɑ, IL-1β, FGF-basic, and IFN-ɣ were significantly higher in KPro with glaucoma compared to KPro without (P = 0.020; 0.008; 0.043; 0.018, respectively). KPro groups had similar characteristics and topical antibiotic/steroid regimen. Levels of IL-1Ra, IL-15, VEGF, and RANTES were significantly higher in KPro with glaucoma compared to controls (P < 0.001; = 0.034; < 0.001; = 0.001, respectively). IL-1β and IFN-ɣ levels were positively correlated with CDR (r = 0.309, P = 0.039 and r = 0.452, P = 0.006, respectively) and IOP (r = 0.292, P = 0.047 and r = 0.368, P = 0.023, respectively). TNF-α and FGF-basic levels were positively correlated with CDR (r = 0.348, P = 0.022 and r = 0.344, P = 0.021, respectively).ConclusionsTNF-α, IL-1β, FGF-basic, IFN-ɣ are elevated in tears of KPro patients with glaucoma and correlate with CDR and IOP. These results show, for the first time in humans, concordance with documented elevations of TNF-α and IL-1β in the murine KPro model. Ocular surface inflammation may reflect inflammatory processes of KPro glaucoma.     

Changes in corneal curvature and visual acuity in North Indian adults after pterygium excision with modified sutureless,glueless limbal-conjunctival autograft

Purpose:To identify the exact time point during after following pterygium excision with a modified technique of sutureless, glueless limbal-conjunctival autograft, when stabilization of the change in corneal curvature is achieved; correlate size of pterygium with uncorrected visual acuity and astigmatism at baseline, and assess changes in these parameters postoperatively over time.Methods:This prospective study longitudinally assessed 30 eyes of 30 north Indian adults with primary pterygium encroaching upon ≥1 mm of the cornea pre- and postoperatively at 1 week and then monthly for 4 months, recording uncorrected (UCVA) and best-corrected logMAR visual acuity, astigmatism and keratometry. Results were analyzed using ANOVA, Mauchly’s test of sphericity with Greenhouse–Geisser correction, and post-hoc test using Bonferroni correction. Pearson’s correlation coefficient r > 0.5 was considered clinically significant, and P < 0.05 statistically significant.Results:Pterygium size was well correlated with pre-operative astigmatism (r = 0.867, P < 0.001) and pre-operative UCVA (r = 0.856, P < 0.001). There was mean improvement of 0.43 logMAR units of visual acuity (P < 0.00001), a mean increase of 0.79D of keratometric value for the flatter meridian (P < 0.00001) and a mean reduction of 2.00D of astigmatism (P < 0.00001). At 2-month follow-up, the keratometric value for the flatter meridian approached the final keratometric reading at 4 months such that the difference was not significant (t = 1.185, P = 0.245). There were no significant complications or recurrence during the follow-up period.Conclusion:Pterygium excision with modified autograft reduced corneal astigmatism and improved visual acuity comparable to classical technique. Alteration in corneal curvature stabilizes 2 months after surgery, when spectacle correction can be given to patients.