角膜入路23-G玻璃体切除在眼外伤的应用

目的观察透明角膜入路的23-G微创玻璃体手术在一期眼外伤处理中的效果。方法回顾性系列病例研究。对26例（26只眼）复杂眼外伤采用角膜入路的晶状体切除及前部玻璃体切除术：在近角膜缘的透明角膜上用23-G穿刺刀做两个切口,分别置微套管,一侧与灌注管相连,另一侧伸入玻切头。通过两个微套管进行角膜入路的晶状体切除及前段玻璃体切除。结果术中无并发症发生,术后随访结束时最佳矫正视力0．5及以上者3只眼（11．54％）,0．1～0．4者8只眼（30．77％）,0．02—0．08者12只眼（46．15％）,数指及以下者3只眼（11．54％）。术后第3天平均眼压为（13．26±4．83）mmHg,术后第7天平均眼压为（14．65±3．91）mmHg（1mmHg=0．133kPa）。18只眼二期植入人工晶状体,9眼经玻璃体视网膜手术处理后,视网膜复位,保留了眼球。结论透明角膜入路的23．G微创玻璃体手术是一期处理眼外伤的有效方法。     

Interactions between ocular surface fluid and cornea related to contact lenses.

PURPOSE: To improve the quantification of damage to the ocular surface, metabolite levels, electrolyte concentrations, and enzyme activities were assayed in corneal epithelium, stroma and tears. METHODS: In rabbits, rinsing or contact lenses were used to induce microtrauma. For more severe trauma, experimental injuries were induced with 1 N NaOH. Human accidents included epithelial lesions and mild chemical burns. Enzymatic test systems and electron dispersive X-ray analyses (EDXA) were employed. Corneal hydration was assessed by wet and dry weights. Interleukins were analysed with ELISA. RESULTS: In contrast to normal eyes, in ocular surface trauma the interaction between tear fluid and cornea played an important part. After wearing contact lenses or rinsing, glucose and lactate levels in the cornea and in tears increased, and ATP and glycogen in the cornea decreased. After epithelial lesions, N-acetylglucose aminidase (NAcGA, E.C.3.2.1.50) was released into the tears. Epithelial defects alone and--much more--rinsing the denuded stromal surface produced an increase of lactate and glucose in tears and a dramatic fall in Na, Cl, and S levels in the stroma. Rinsing with phosphate induced corneal calcification. IL-1 and IL-6 were increased in human corneal buttons from patients with trauma and inflammation. CONCLUSIONS: Biochemical analyses may be useful to quantify trauma to the ocular surface.     

靶向血管内皮生长因子治疗眼新生血管的研究进展

眼新生血管的形成严重破坏眼的结构和功能,引起不同程度的视力障碍,因此研究新生血管的生成机制并寻找有效的治疗方案是目前急需攻克的研究课题.血管内皮生长因子(vascular endothelial growth factor,VEGF)是目前发现的最为强大和专一的刺激内皮细胞增生的因子,在新生血管生成中起着中心作用.通过眼内注射VEGF 受体嵌合蛋白、抗VEGF单克隆抗体、靶向VEGF 小干扰RNA均可不同程度地抑制眼内新生血管生成.本文就靶向VEGF治疗眼新生血管的研究进展进行综述.     

The effect of therapeutic soft contact lenses on antibiotic delivery to the cornea

The effects of high (71%) and low (38.6%) water content lenses on antibiotic delivery to the cornea were studied in rabbits by measuring corneal tobramycin concentrations 1, 2, 4 and 6 hours after topical application at intervals of 15 minutes. In the presence of the low water content lens corneal drug levels were higher than in control corneas for every time point assayed. This difference was only significant at 4 hours (P less than 0.05). In eyes wearing the high water content contact lens corneal drug concentration was also higher at every time point tested except one hour. The difference was significant only at 4 hours (P less than 0.01). The data suggest that in the normal, noninflammed eye, the presence of a therapeutic soft contact lens will not compromise aminoglycoside delivery to the cornea.     

Evidence for N-acetylmannosamine as an ocular receptor for P. aeruginosa adherence to scarified cornea

This study provides evidence for an N-acetylmannosamine (manNac) receptor mediating in vivo bacterial adherence of P. aeruginosa to the scarified corneal epithelial surface. Bacteria, whether exposed to the inhibiting sugar or not, did not adhere immediately after inoculation, but required time in contact with the scarified corneal surface to adhere and adherence increased with time. Organisms were observed primarily adherent to the surface of epithelial cells lining the wound and were less frequently seen on areas of denuded stroma. Saturation of binding sites on the bacterial surface by manNac inhibited attachment of the organisms to newly exposed surface membrane receptors. In vivo protection studies showed excellent correlation with quantitative analysis of scanning electron micrographs, in that the number of adherent organisms at the corneal surface at 60 min following scarification and bacterial inoculation was decreased significantly by prior treatment of the bacteria with manNac when compared with PBS or the other monosaccharides. These data were confirmed by quantitative bacterial culture of excised corneas which had been similarly infected in vivo with PBS or manNac treated organisms.     

Application of miniosmotic pumps for liposomal drug delivery to the ocular lens

The feasibility of using miniosmotic pumps in conjunction with specifically targeted liposomes to deliver agents directly to the ocular lenses of rabbits in vivo was examined in a pilot study. Concanavalin A was used to provide specific targeting of the vesicles to the lenses of the treated eyes. Seven days after pump installation, the animals were sacrificed and tissue samples from both control and treated eyes were examined for the presence of the administered agent. Four animals were treated with liposomally encapsulated Sorbinil and specific delivery to the lenses of the treated eyes was demonstrated by fluorescence spectroscopy. Two other animals were treated with liposomally encapsulated 3H-8-MOP, and specific delivery of the drug to the treated lenses was demonstrated by phosphorescence spectroscopy and by liquid scintillation counting. The drugs delivered to the treated eyes could not be detected in any of the tissues or fluids of the contralateral control eyes. Except for the ocular lens, these agents could not be demonstrated to any substantial degree in the other tissues of the treated eyes.     

Cell penetrating peptide POD mediates delivery of recombinant proteins to retina, cornea and skin

Recently we described a novel cell penetrating peptide, peptide for ocular delivery (POD) that could deliver small molecules including fluorescent dyes into retinal cells. The objective of the current study was to examine whether biologically relevant macromolecules such as proteins, genetically fused with POD could also be delivered into retinal tissues in vivo. We generated a POD-GFP fusion protein and examined its cell and tissue penetrating properties. We found that endogenously expressed POD-GFP fusion protein localized to the nucleus, suggesting that POD acts as a nuclear localization signal. Adenovirus (Ad) vectors expressing POD-GFP fusion protein were constructed and the recombinant protein was purified from Ad-infected human embryonic retinoblasts (HER). Exogenously supplied POD-GFP fusion protein rapidly transduced A549 and HER cells and colocalized in part with markers of late endosomes, from which it could escape. Following subretinal delivery, POD-GFP localized to the retinal pigment epithelium and the photoreceptor cell bodies. When injected into the vitreous, POD-GFP localized to the ganglion cells and the inner nuclear layer of the retina as well as the lens capsule. Topical application of POD-GFP to ocular surfaces resulted in uptake by the corneal epithelium. POD-GFP also transduced non-ocular tissues, including the epidermis of the skin following topical application.     

Presence of Langerhans cells in the central cornea linked to the development of ocular herpes in mice.

Recurrences of herpetic stromal keratitis are believed to be initiated by reactivation of herpes simplex virus infection, probably in the trigeminal ganglion. Genetic features of the virus and the host as well as the immune status of the host influence the outcome of infection. Following infection on the snout with HSV-1, mice with normal corneas usually develop mild anterior segment disease. We studied the induction of herpetic infection in mice that had abnormal corneas, containing center due to trauma or a spontaneous dystrophy. The corneal abnormality led to more frequent herpetic stromal keratitis and more severe anterior chamber reaction. In addition, we found that snout-infected mice with dystrophic corneas had an increased risk of dying from viral infection. Our data suggest that not only the strain of virus and the genetic background of the mouse, but also the state of the cornea itself, can contribute to susceptibility to ocular herpes infection.     

Herpes simplex virus recovery in neural tissues after ocular HSV shedding induced by epinephrine iontophoresis to the rabbit cornea

Ocular HSV-1 shedding from latently infected rabbits was induced by iontophoresis of 0.01% epinephrine into the eye. Anodal Iontophoresis of epinephrine was performed at 0.8 mAmps for 8 min once a day for 3 consecutive days. Shedding was determined by the presence of HSV-1 in the preocular tear film obtained via eye swabs. Bilateral epinephrine iontophoresis performed on selected days during 220-280 days after inoculation resulted in HSV-1 shedding in 75% of the eyes (30/40) and 100% of the rabbits (20/20). Following the induction of ocular HSV-1 shedding, rabbits were killed and selected neural tissues were homogenized. Cell-free preparations were assayed for the presence of infectious virions using primary rabbit kidney cell monolayers. When the tissues were homogenized immediately after death, virus was detected in only one neural tissue, the trigeminal ganglia. However, when the tissues were incubated in vitro for 18-24 hours prior to the homogenization, infectious HSV-1 was recovered from homogenates of the trigeminal ganglion, superior cervical ganglion, the ophthalmic branch of the trigeminal nerve, and the root entry zone of the trigeminal nerve. A relationship was noted between the time of the last ocular shedding and recovery of infectious HSV from the tissue homogenates. Furthermore, a positive correlation in 11 eyes between the recovery of HSV-1 from the perocular tear film and HSV-1 recovery from one or more corresponding neural tissues was found. These results suggested that epinephrine iontophoresis to the cornea triggered an "alteration" in the state of the virus in the neural tissues of the latently infected rabbits and that the change can be related to the induced ocular shedding.     

A rabbit model for assessing the ocular barriers to the transscleral delivery of triamcinolone acetonide

Transscleral delivery of triamcinolone acetonide into the vitreous using sub-Tenon's injections may be a safer alternative to reduce the sight-threatening complications of direct intravitreal injections. However, sub-Tenon's injections have demonstrated low and poorly sustained vitreous drug levels in animal studies. To improve our understanding of the clearance mechanisms of corticosteroids, we evaluated vitreous drug levels following sub-Tenon's injection of triamcinolone acetonide in rabbits with selective elimination of conjunctival lymphatic/blood vessels and the choroid. Pigmented rabbits were given a sub-Tenon's injection of a preservative-free triamcinolone acetonide formulation of either a 10- or 20-mg dose in the superotemporal quadrant. The effect eliminating both conjunctival and choroidal clearance was evaluated by injecting the drug, followed by immediate euthanasia, effectively terminating both lymph and blood flow in the conjunctiva and choroid. To inhibit only the clearance from conjunctival lymphatics/blood vessels of a sub-Tenon's injection of triamcinolone acetonide, a group of rabbits had a 'conjunctival window' created by incising an 7 mmx7 mmx7 mm square through the conjunctiva to bare sclera in the superotemporal quadrant. To eliminate only the clearance of drug from the choroidal circulation, cryotherapy was performed in another group of rabbits creating a chorioretinal scar in the superotemporal quadrant. Following the sub-Tenon's drug injection, the eyes were enucleated in all groups after 3 hr and vitreous drug levels were measured with HPLC. In normal animals, a 10-mg sub-Tenon's injection showed no detectable vitreous drug levels; however, a 20-mg injection showed positive vitreous drug levels. This suggested that collectively, the transscleral clearance mechanisms inhibiting delivery into the vitreous may be saturated with a drug depot that has a higher release rate. A 10-mg sub-Tenon's drug depot was able to deliver drug into the vitreous when both the conjunctival and choroidal drug clearance was eliminated by euthanizing the animal immediately following the drug injection. In rabbits that had only a 'conjunctival window', selectively eliminating conjunctival drug clearance, vitreous drug levels were detected. However, in rabbits that had only cryotherapy, selectively eliminating choroidal drug clearance, vitreous drug levels were not detected suggesting that the conjunctival lymphatics/blood vessels may be an important barrier to the transscleral delivery of triamcinolone acetonide. Variability in the vitreous drug levels between rabbits in each group precluded statistical testing. In summary, the rabbit appeared to demonstrate saturable ocular barriers to transscleral delivery of triamcinolone acetonide into the vitreous following a sub-Tenon's injection. The results suggested that the conjunctival lymphatics/blood vessels may be an important barrier to the delivery of triamcinolone acetonide to the vitreous in this rabbit model. The barrier location and clearance abilities of the ocular tissues are important to consider when developing a successful transscleral drug delivery system. Animal models, retaining the dynamics of blood and lymph flow, may improve the basic understanding of the ocular barriers involved with transscleral drug transport and warrants further investigation.     

眶底爆裂性骨折致眼球运动障碍的上颌窦手术进路治疗

目的 观察上颌窦进路手术治疗眶下壁爆裂性骨折所致眼球运动障碍的临床效果.方法 对12例12只眼眶下壁爆裂性骨折伴复视及眼球运动障碍者,眼眶CT显示:眼外肌眶内软组织嵌顿于眶下壁骨折区,伤后观察2周,复视及眼球运动障碍无明显改善,采用上颌窦进路行眶下壁骨折复位术.术后随诊3～6个月.结果 12例患者术中开放上颌窦后可清晰观察到眶下壁骨折区各个边界及眶内软组织嵌顿情况,术中均将嵌顿在眶底骨折处的眶内组织推送回眶内,眶底骨折复位.术后12例患者中10例各方向眼球运动不受限,无复视,2例正前方及下方无复视,向上方运动轻度受限.术后1例并发上颌窦炎,经上颌窦冲洗治愈.结论 上颌窦进路早期治疗单纯眶下壁爆裂性骨折所致眼球运动障碍是有效的.     

Topical cyclosporine to control ocular surface disease in patients with chronic glaucoma after long-term usage of topical ocular hypotensive medications

Purpose

To evaluate changes in ocular surface and central corneal sub-basal nerve fiber layer (SBNFL) after topical cyclosporin therapy in chronic glaucoma patients on long-term topical antiglaucoma therapy.

Methods

A prospective comparative study of ocular surface evaluation of chronic glaucoma patients on long-term topical therapy treated concurrently with a topical cyclosporine 0.05% twice daily for 6 months and controls was done. The study parameters evaluated at recruitment and at the 6-month follow-up included details of topical antiglaucoma medications, visual acuity, intraocular pressure, ocular surface evaluation parameters (TBUT, Schirmers I, ocular surface staining scores and ocular surface disease (OSD) index score (OSDI)), central corneal sensation (Cochet Bonnett aesthesiometer), and central confocal microscopy to study the SBNFL density (SBNFLD).

Results

Thirty-two eyes of 16 patients with chronic glaucoma and 30 eyes of 15 normal subjects as controls were studied. Mean TBUT, pre/post CsA treatment was 8.67±3.01/12.24±1.83 s (P=0.007). Mean conjunctival/corneal staining scores pre/post CsA treatment were 3.38±1.93/1.50±0.718 (P=0.00) /5.19±1.82/1.81±0.78 (P=0.098), respectively. Mean OSDI pre/post CsA treatment scores were 30.63±14.61/14.76±6.06 (P=0.007). Mean corneal sensations scores pre/post CsA treatment were 4.64±0.46/4.94±0.39 (P=0.002). Central corneal SBNFLD pre and post CsA treatment was 8811.35±2985.29/10335.13±4092.064 μm/mm² (P=0.0001).

Conclusions

Schirmer''s test, ocular surface staining scores, OSDI, corneal sensations, and corneal SBNFLD showed a statistically significant improvement following a 6-month concurrent topical CsA therapy.     

The point-to-point variation of oxygen delivery to a cornea covered by a hydrogel contact lens in the open eye

The amount of oxygen reaching a point on a cornea covered by a stationary hydrogel contact lens depends upon the oxygen transmissibility of that portion of the lens immediately anterior to that point. Calculation of the oxygen flux to the cornea requires that the oxygen tension at the lens-cornea interface be known. Previously published investigations give this oxygen tension for a variety of hydrogel lenses, thereby permitting calculation of areal distribution of oxygen delivery to the cornea. The difference in oxygen flux to the cornea from the lens center to the periphery for an optically powered lens is less extreme than is predicted from center-to-periphery variation in lens thickness. The uniformity of oxygen flux from center to periphery may explain why hydrogel lenses of high optical power can be worn successfully.     

Review: Emerging strategies for antimicrobial drug delivery to the ocular surface: Implications for infectious keratitis

Infectious keratitis is a medical emergency that can cause severe visual morbidity if not treated promptly. Depending upon the causative microorganism, effective management of infectious keratitis requires frequent application of antibacterial, antifungal, or antiviral eye drops, which may have low bioavailability, undesirable side effects, and poor patient compliance. Ocular formulations of antimicrobials that can increase corneal permeation and provide extended presence on ocular surface are being developed. Such formulations include nanoparticles, mucoadhesives, in situ forming hydrogels, and contact lenses. Testing of these formulations in in vitro models and ex vivo excised corneas, and in vivo rabbit testing have demonstrated increased bioavailability and extended presence on the cornea. Many of these formulations have also demonstrated success in treating infectious keratitis in animal models. However, the majority of studies have evaluated fluoroquinolone antibacterials, and more studies are needed to test the delivery of antifungal drugs. Moreover, additional efficacy data in animal models and future studies in humans to determine the duration of inhibitory concentrations of these antimicrobials in tear fluid will be required to prove the effectiveness of these formulations for clinical management of infectious keratitis.     

A topical or oral carbonic anhydrase inhibitor to control ocular hypertension after cataract surgery

PURPOSE: To compare the effects of oral acetozolamide and topical 2% dorzolamide to prevent ocular hypertension after cataract surgery. METHODS: This prospective, randomized study comprised 62 consecutive patients who had extracapsular cataract extraction and posterior chamber intraocular lens implantation. Patients received either oral acetozolamide (Diazomide) 250 mg three times daily or topical dorzolamide 2% (Trusopt) three times daily, for three days. Intraocular pressures (IOP) were measured by Goldmann applanation tonometry preoperatively and 16, 40, 64 hours postoperatively. RESULTS: IOP in the dorzolamide group peaked at 16 hours and had returned to preoperative values by 40 hours. In the acetozolamide group mean IOP was significantly higher than preoperative values at 16, 40 and 64 hours (p<0.05). At all three postoperative measurement times, mean IOP was significantly higher in the acetozolamide group (p<0.05). CONCLUSIONS: Topical dorzolamide 2% offers better IOP control than oral acetozolamide to prevent ocular hypertension after cataract surgery.     

阳离子聚合物介导下白细胞介素1受体拮抗剂基因兔角膜原位转染及其表达

目的 探讨阳离子聚合物即线性聚乙烯亚胺（PEI）介导下兔角膜基质注射PEGFP-IL-1ra质粒进行基因角膜原位转染的有效性和安全性。方法 以人cDNA文库为模板进行聚合酶链反应（PCR）,获得人IL-1ra cDNA片段,构建重组质粒PEGFP-hIL-1ra。以阳离子聚合物为介导转染角膜内皮细胞,通过绿色荧光蛋白（GFP）示踪、蛋白免疫印迹技术检测转染后IL-1ra基因和蛋白的表达。实验组30只Wistar大鼠角膜基质注射PEGFP-hIL-1ra质粒和PEI-in-vivo的混合溶液20μl（含10μg质粒）,对照组15只Wistar大鼠角膜基质注射PEI-in-vivo溶液20μl。注射后1、3、6、14、21d,收集角膜通过HE染色、透射电镜、锥虫蓝-茜素红染色、免疫组织化学观察IL-1ra基因角膜原位转染后的细胞结构和功能的变化。荧光显微镜下追踪IL-1ra-GFP融合蛋白在角膜的表达部位和表达强度。结果 以cDNA文库为模板扩增出hIL-1ra cDNA片段,构建重组质粒PEGFP-hIL-1ra。经PstⅠ和BamHI酶切及DNA测序证实了插入片段方向和大小正确。PEI-in-vitro介导下PEGFP-hIL-1ra转染角膜内皮细胞12h后,可见10％～15％细胞中有GFP荧光表达。Western-blotting检测可见相对分子质量为44000的hIL-1ra-GFP蛋白表达。PEGFP-hIL-1ra质粒和PEI-in-vivo角膜基质注射后1d,角膜上皮基底细胞可见荧光条带,6d时全角膜荧光强度达到高峰,14d开始减弱,21d角膜上皮层尚存微弱荧光。对照组观察期内始终未见绿色荧光。实验组角膜HE染色未见病理性改变,角膜上皮基底细胞层p63抗体阳性;锥虫蓝-茜素红联合染色未见角膜内皮细胞损伤;透射电镜显示角膜各层细胞的细胞质内可见IL-1ra-GFP颗粒,未见细胞器的损害。结论 阳离子聚合物介导下角膜基质注射PEGFP-hIL-1ra质粒可快速、有效地将IL-1ra基因转入角膜并表达,为临床上使用抗炎细胞因子IL-1ra对角膜免疫炎性反应相关疾病进行基因治疗提供了新的技术平台。（中华眼科杂志,2006,42：686-693）     

Voluntary control of long-range motion integration via selective attention to context

Ambiguous stimuli can look different in different contexts. Here we demonstrate that subjective appearance of motion depends not only on current visual input but critically on which aspects of the context are attended. Observers fixated a central oblique test grating flanked by two pairs of orthogonally oriented context gratings arranged in a cross (+) configuration. Each context pair could induce the test stimulus to appear to switch from diagonal motion to either horizontal motion (due to one context pair) or vertical motion (due to the other). Spontaneous switching between these motion states was observed under free viewing. We demonstrate that observers can voluntarily select between specific states when cued to attend selectively to one or other context pair in an alternating manner. Concurrent reports of perceived test stimulus motion depended specifically on which context was currently attended, indicating a high degree of "cued-control" over subjective state via attended context. Further experiments established that the perception was nevertheless still constrained by physical stimulus context as well as by attentional selection among that context. Moreover, the attentional control evident here did not seem reducible solely to local contrast gain modulation of the attended vs. ignored context elements. Selective attention to different parts of the context can evidently resolve the ambiguity of the test grating, with integration arising selectively for those components that are jointly attended. Such selective integration can result in substantial voluntarily controlled changes in phenomenal perception.