Protection against corneal hyperosmolarity with soft-contact-lens wear

Hyperosmotic tear stimulates human corneal nerve endings, activates ocular immune response, and elicits dry-eye symptoms. A soft contact lens (SCL) covers the cornea preventing it from experiencing direct tear evaporation and the resulting blink-periodic salinity increases. For the cornea to experience hyperosmolarity due to tear evaporation, salt must transport across the SCL to the post-lens tear film (PoLTF) bathing the cornea. Consequently, limited salt transport across a SCL potentially protects the ocular surface from hyperosmotic tear. In addition, despite lens-wear discomfort sharing common sensations to dry eye, no correlation is available between measured tear hyperosmolarity and SCL-wear discomfort. Lack of documentation is likely because clinical measurements of tear osmolarity during lens wear do not interrogate the tear osmolarity of the PoLTF that actually overlays the cornea. Rather, tear osmolarity is clinically measured in the tear meniscus. For the first time, we mathematically quantify tear osmolarity in the PoLTF and show that it differs significantly from the clinically measured tear-meniscus osmolarity. We show further that aqueous-deficient dry eye and evaporative dry eye both exacerbate the hyperosmolarity of the PoLTF. Nevertheless, depending on lens salt-transport properties (i.e., diffusivity, partition coefficient, and thickness), a SCL can indeed protect against corneal hyperosmolarity by reducing PoLTF salinity to below that of the ocular surface during no-lens wear. Importantly, PoLTF osmolarity for dry-eye patients can be reduced to that of normal eyes with no-lens wear provided that the lens exhibits a low lens-salt diffusivity. Infrequent blinking increases PoLTF osmolarity consistent with lens-wear discomfort. Judicious design of SCL material salt-transport properties can ameliorate corneal hyperosmolarity. Our results confirm the importance of PoLTF osmolarity during SCL wear and indicate a possible relation between PoLTF osmolarity and contact-lens discomfort.     

Conjunctival flap advancement with or without scleral graft for hypotony maculopathy after trabeculectomy

AIM: To introduce a novel technique for transscleral fixation of the PC-IOL that requires no sutures on the IOL haptics. METHODS: Instead of suturing polypropylene onto the IOL haptics, the method simply winds the thread on the haptics. Fifteen eyes of 15 patients underwent this technique and were followed up for more than 18 months. Surgical outcomes and post-operative complications were evaluated and compared with those of the conventional transscleral fixation method. RESULTS: Postoperative cylinder was significantly lower in the thread winding group than in the conventional transscleral fixation method group (-1.02±0.46 diopters vs -1.57±0.77 diopters; P=0.01). Further, no postoperative complications, such as optic capture, IOL dislocation, and hyphema, were detected in the thread winding group. CONCLUSION: We believe that our thread winding technique is better than previously reported methods because it is simple, mechanically stable, and free from suture-related complications.     

不同区域晶状体上皮细胞基因表达差异分析

【目的】比较不同区域猪晶状体上皮细胞的基因表达在转录组水平上的差异。【方法】解剖显微镜下分离晶状体前囊膜，将附着于其上的上皮细胞分为中央（直径为10．56mm）和周边两部分。分别提取两个样本的总RNAs并经PCR扩增，以Cy3和Cy5分别标记扩增的中央与周边部分的cDNA。与含7548个基因的表达谱芯片杂交，经图像分析，生物信息学处理获得基因表达在转录水平差异的相关信息。【结果】中央与周边区域的猪晶状体上皮细胞在转录组水平共鉴定出952个有效表达的基因点，其中差异表达基因261个．以中央区域为参照，周边上皮细胞mRNA上调137个，下调124个。差异表达基因主要涉及的功能有：细胞周期与凋亡、细胞骨架蛋白及细胞外基质、转录、细胞信号分子等。【结论】中央与周边区域猪晶状体上皮细胞基因表达在转录组水平上差异明显。这类差异呈明显的功能聚类。     

白内障超声乳化人工晶体术后视网膜脱离临床分析

目的 探讨超声乳化白内障人工晶体术后视网膜脱离的特点及手术疗效。方法 对16例视网膜脱离患者做常规巩膜扣带术或玻璃体切割联合眼内填充进行回顾性分析。结果 视网膜脱离手术后完全复位14例，一次复位率为87．5％，另2例患者经二次手术后完全复位，视力均有不同程度提高。结论 对该类患者术前应仔细检查，选择合适的手术方式尽早施行手术，以提高疗效。     

紫外线对晶状体上皮细胞损伤的研究进展

紫外线，特别是紫外线B，是老年性白内障的环境致病因素，晶状体上皮细胞生理状态的改变是白内障发生的早期表现。本综述总结了近年来国内外关于紫外线损伤对晶状体上皮细胞影响的研究，以及紫外线对晶状体上皮细胞的生物损伤效用和损伤机制。     

接触镜与泪液形态关系的临床评价

目的 :观察配戴不同种类接触镜后眼表面泪膜的形态、稳定性及泪液量的变化。方法 :对日戴SCL、RGPCL和Ortho KCL的 2 14名近视患者 4 2 8只眼 ,利用表面泪膜观察装置 (DR 1)观察戴镜前后眼表泪液膜和戴镜状态下镜上泪液膜的形态分级 ,同时测定泪膜破裂时间 (BUT)。利用酚红染色棉丝测定SCL戴镜前后的泪液量 ,并用折射仪 (AtagoCL 1)测量SCL含水量的变化。结果 :SCL配戴者随戴镜时间延长 ,BUT明显缩短 (P <0 .0 1) ,RGPCL和Ortho KCL配戴者戴镜 5年以内 ,BUT无明显变化 (P >0 .0 5 )。戴镜后RGPCL ,Ortho KCL和非戴镜正常眼三组间眼表泪膜分级比例差异无显著性 ,SCL组Ⅰ级比例为 6 .5 % ,显著低于其他组(16 .1%～ 2 3.0 % )。镜上泪膜 ,SCL、RGPCL和Ortho KCL三组均以Ⅳ级为主 (分别占 5 4 .4 %、5 3.4 %和 5 1.5 % ) ,SCLⅠ级比例仅 1.9% ,显著低于另二组 (分别占 6 .2 %和 12 .4 % )。SCL配戴者随戴镜时间延长 ,泪液量轻度减少 ,SCL含水量在戴镜 1w后即显著降低。结论 :科学配戴接触镜对泪液膜质量无明显影响 ,但SCL长期使用可能对泪膜有一定干扰作用。     

Modulation of cytokine production from an EpiOcular corneal cell culture model in response to Staphylococcus aureus superantigen

The present study investigated the hypothesis that Staphylococcus aureus enterotoxin B (SEE) produces epithelial cell death and releases inflammatory cytokines that produce stromal infiltration during contact lens induced peripheral ulceration. Epithelial cells were incubated with different doses of SEB for various time periods. Culture supernatants were assayed for cytokines IL- lo, IL-6 and chemotactic agents IL-8 and LTB,. SEE induced the production of IL- I p and IL-8. Epithelial cells exposed for longer periods (48 h) with low concentrations of SEB produced significantly higher levels (N0.02) of IL-Ip and IL-8 (P<0.05) compared t o a 24 h exposure. SEB did not induce the production o f IL-6 and     

The effect of cigarette smoke on the bovine lens

Smoking has recently been identified from epidemiological studies as a possible cause of cataract but the mechanism involved is not known. Therefore, our laboratory has initiated studies aimed at elucidating these mechanisms. Whole bovine lenses were cultured to examine possible effects of cigarette smoke on amino acid uptake and protein synthesis. Cigarette smoke, filtered to remove nicotine and tar which would not reach the eye in vivo, was bubbled through culture medium. Bovine lenses were incubated in this medium in the presence of [¹⁴C]-leucine for four days. A significant decrease in uptake of [¹⁴C]-leucine and a decrease in protein synthesis were found with smoke treated lenses. This is the first demonstration of an effect of cigarette smoke on the lens. Further work is needed to determine how this metabolic upset is mediated and how it could lead to cataract.