A photopolymerized sealant for corneal lacerations

PURPOSE: To determine whether a novel photocrosslinkable polymer synthesized from hyaluronic acid would seal experimental full-thickness corneal lacerations in a rabbit model. METHODS: A solution of hyaluronic acid was modified with methacrylate groups (HA-MA), precipitated, dried, reconstituted in an aqueous solution, and sterilized before use. The viscous polymer solution was applied to 38 of 43 experimental corneal lacerations in rabbits and subsequently irradiated with a low-intensity argon laser beam to produce a clear flexible polysaccharide hydrogel patch. The ability of this sealant to repair corneal lacerations was evaluated in four types of full-thickness, 3-mm corneal wounds (linear, linear + epithelium removed, stellate, and stellate + epithelium removed). Slit-lamp examinations, measurements of intraocular pressure, Seidel tests, and histologic studies were performed at selected intervals to evaluate the wound and determine the rate of healing. RESULTS: Corneal perforations were completely sealed and the anterior chambers had reformed by 6 hours in HA-MA-treated eyes. There was no evidence of leakage at this or later times in 37 of the 38 eyes. Intraocular pressure had risen to near-normal levels by day 7 in all four groups, and the sealant was still present in most eyes at day 7. In contrast, the anterior chambers did not re-form in control eyes (five) with untreated perforations because of aqueous leakage through the wounds. Minimal inflammation was observed clinically or in histologic sections of treated corneas. There was extensive proliferation of stromal cells and formation of new extracellular matrix at the wound edges, which became tightly adherent between days 4 and 7. CONCLUSION: Our novel photocrosslinkable methacrylated hyaluronan polymer sealed 97% (37/38) of the experimental corneal lacerations. HA-MA may prove useful for sealing corneal lacerations in patients and for other sutureless ophthalmic surgical procedures.     

Progress in cataract surgery using microsurgical technique.

A microsurgical technique for cataract extraction is presented. The operations were performed with a corneal incision and a continuous nylon 10-0 suture. This technique is evaluated by the study of 1289 cases, consecutively operated on. The complication rate was very low. Haemorrhage in the anterior chamber was found in 1%. Delayed reformation of the anterior chamber occurred in only two cases. No cases of iris prolapse occurred. The intraocular pressure was not interferred with by the operation. Wound rupture following removal of the suture three months post-operatively occurred in 1%. The advantages of the corneal incision and continuous nylon suture are discussed (less irritation, good and secure wound closure).     

Controlled reduction of postkeratoplasty astigmatism

Corneal transplants were performed in 50 eyes using eight deeply placed interrupted 24 micron (10--0) monofilament nylon sutures followed by a more superficial continuous 16 micron (11--0) monofilament nylon suture placed around the wound in 16 equal bites. After surgery the 24 micron sutures in the steepest corneal meridian based on central and peripheral keratometry were cut. This suture technique permitted the donor cornea to assume its normal shape more rapidly while reducing the induced postkeratoplasty astigmatism. With this technique corneal astigmatism was reduced an average of 3.4 diopters (range 0--10 diopters), which allowed patient to achieve a mean visual acuity at three months of 20/50 and at 11 to 13 months of 20/35. Although this suture technique does not eliminate postkeratoplasty astigmatism, it permits the surgeon to reduce actively high degrees of astigmatism present after corneal transplantation.     

Influence of suture regularity on corneal astigmatism after penetrating keratoplasty

Purpose: To investigate whether suture regularity affects corneal astigmatism after keratoplasty. Methods: Twenty‐one patients undergoing penetrating keratoplasty for various corneal diseases were included in the study. The grafts were sutured in place using a single‐running Nylon 10‐0 suture, taking 24 bites. Immediately after surgery, standard calibrated images of the grafted eye were captured and stored. Using a dedicated image analysis programme, stitches and needle points were identified, and a number of suture regularity variables were calculated. Corneal topographic images were obtained before suture removal (12 months after surgery) and 3 months after suture removal (18 months after surgery). Topographic measures of astigmatism [surface regularity (SRI), surface asymmetry index (SAI) and simulated keratometric astigmatism] were calculated and correlated with the computed suture regularity variables. Results: The average stitch length was 3.04 ± 0.28 mm and the distance between the outer needle points was 2.53 ± 0.09 mm. The SRI was 1.26 ± 0.36 and the SAI was 1.59 ± 0.67 after 12 months; these decreased to 1.03 ± 0.48 and 0.92 ± 0.46 after 18 months, respectively. Corneal astigmatism was 6.38 ± 2.99 and 5.87 ± 3.13 dioptres after 12 and 18 months, respectively. Suture regularity did not affect SAI, SRI or corneal astigmatism significantly 12 months after surgery. Eighteen months after surgery (3 months after suture removal), the standard deviation on the original stitch length was found to significantly increase corneal astigmatism. In addition, the size of the counter‐clockwise angle between stitch and graft radian was correlated significantly with a lower SRI. Conclusion: The origin of corneal astigmatism after penetrating keratoplasty is multifaceted. Regular stitch length and stitch advancement on the surface appears to improve the optical quality of the graft after suture removal. Factors such as stitch depth, suture tension and variations in wound construction might also be important predictors of corneal astigmatism after penetrating keratoplasty.     

纤维蛋白胶治疗兔大的不规则角膜穿通伤

背景 缝线缝合是目前标准的角膜穿通伤治疗方法,缝线缝合的缺点促使人们探索非缝合的手术方法,组织黏合剂是一种有前景的非缝合替代手术方法. 目的 探讨用纤维蛋白胶治疗兔大的不规则角膜穿通伤的效果.方法 18只清洁级健康白色獭兔,按照随机数字表法分成缝合组和黏合组,用15°角膜穿刺刀在角膜非瞳孔区形成V字形、总长度为6 mm的角膜全层穿通伤,缝合组和黏合组分别用10-0缝线对位间断缝合3～5针或用纤维蛋白胶联合临时缝线和治疗性绷带角膜接触镜治疗,每只兔均以右眼为实验眼,左眼为自身对照.比较2个组手术时间,并对术后裂隙灯显微镜观察结果进行比较,分别于术后1、3、8周行角膜组织病理切片评估2个组伤口的愈合修复情况.结果 黏合组的平均手术时间为(3.48±0.48) min,显著低于缝合组的(7.77-±1.30) min,差异有统计学意义(t=9.28,P＜O.01).术后裂隙灯显微镜观察发现,黏合组伤口愈合快且平整.角膜组织病理学检查发现,黏合组伤口愈合规则,炎症反应轻,无新生血管形成;而缝合组纤维排列不整齐,缝线周围有大量炎性细胞及巨噬细胞浸润,炎症反应较重,术后3周发现有新生血管形成.结论 与传统缝线相比,采用纤维蛋白胶联合临时缝线和治疗性绷带角膜接触镜的方法治疗兔大的不规则角膜穿通伤具有操作简单、手术时间短、术后刺激小、炎症反应轻、愈合时间短、伤口愈合规则、无新生血管形成的优点.     

Visual outcome after penetrating keratoplasty with double continuous or combined interrupted and continuous suture wound closure.

We reviewed the consecutive records of 296 patients who underwent corneal transplantation at our institution to compare visual outcome between those who underwent double continuous suture wound closure and those who underwent a combination of interrupted and continuous suture wound closure. Of 156 patients on whom one of these closure techniques was performed, 33 patients satisfied our inclusion and exclusion criteria. Visual outcome between the two groups was compared at three, six, and 12 months. We found significant differences (P less than .05) in average corneal curvature and refractive spherical equivalents (steeper and more myopic, respectively, for double continuous suture wound closure); keratoscopic astigmatism, refractive cylindrical error; and average number of postoperative visits (greater for combined interrupted and continuous suture wound). Visual acuity without correction was significantly better at three months in the group that received double continuous sutures (P = .026). We found no marked difference in best-corrected visual acuity, frequency of graft rejection, requirement for contact lens fit, ratio of refracted vs potential visual acuity, or intraocular pressure. Patients who underwent double continuous suture closure had more rapid visual rehabilitation, had steeper corneas, and less astigmatism than patients who underwent the combined technique suture closure.     

Suture adjustment for postkeratoplasty astigmatism

Excessive corneal astigmatism following penetrating keratoplasty is a frequent problem. A technique that adjusts a single running 10-0 nylon suture after keratoplasty was used in this series of patients. The procedure requires a keratometer, slitlamp, topical anesthesia, and tying forceps. In 52 eyes, with an average of 10.0 diopters of keratometric astigmatism, we adjusted the suture to flatten the steep corneal axis. We were able to reduce astigmatism an average of 7.2 diopters and this remained stable three months post wound revision.     

Scleral fixation without conjunctival dissection

Scleral fixation of intraocular lenses (IOLs) and adjunctive capsular devices can be performed under the protection of a scleral flap. A modification of this technique uses a scleral pocket initiated through a peripheral clear corneal incision. Full-thickness passage of a double-armed suture through the scleral pocket and conjunctiva, with subsequent retrieval of the suture ends through the external incision for tying, facilitates scleral fixation. This modification offers several advantages over traditional methods: It eliminates the need for conjunctival dissection and scleral cauterization; a scleral pocket affords a greater surface area for suture placement through an ab externo or ab interno approach; retrieval of the sutures through the external corneal incision and subsequent tying allows the suture knot to pass under the protective roof of the scleral pocket, negating the need for suture knot rotation; and the architecture of the scleral pocket eliminates the need for sutured wound closure. Suture retrieval and scleral fixation through a corneoscleral pocket offers a refined method for fixation of IOLs and other intraocular adjunctive devices.     

Corneal wound healing in tenascin knockout mouse

PURPOSE: Tenascin (TN) is a large hexameric extracellular matrix glycoprotein that is expressed in developing organs and tumors. It has also been reported that TN is expressed in the embryonic cornea and during corneal wound healing. However, the role of TN in the cornea is not fully known. In this study, the role of TN in corneal wound healing was examined using the TN knockout (KO) mouse. METHODS: Two different injuries (a linear perforation wound and two 10-0 nylon suture wounds) were made separately on the corneas of both TNKO and congenic wild-type mice. The corneal wound healing was compared histologically, and the expression of TN and fibronectin (FN) on the injured cornea was examined immunohistochemically and by immunoblot analysis. RESULTS: Based on histologic analysis, there was no significant difference in the wound healing process between wild-type and TNKO mice in the linear incision experiment. However, the corneal stromata of TNKO mice were compressed prominently and devoid of migrating keratocytes in suture injury, which induced a more significant amount of TN than perforation wounds. Although FN expression on the sutured corneas of TNKO mice was upregulated during suture injury, the amount of FN protein was smaller than that of wild-type mice at the same time points after injury. CONCLUSIONS: In suture wounds, TN appears to enhance the amount of FN expression, and a lack of TN may impair stromal cell migration. TN plays a significant role in corneal wound healing, especially for wounds with mechanical stress.     

Corneal wound dehiscence after penetrating keratoplasty

PURPOSE: To describe the clinical features of corneal wound dehiscence after penetrating keratoplasty (PK) after trauma and suture removal. METHODS: A retrospective review of all eyes needing resuturing in the 5-year period of July 2000 to June 2005 was performed. In total, 76 eyes of 76 patients needed wound resuturing. The indications were early wound leak, wound dehiscence, broken suture, or loose suture. In 29 of the 76 cases, the indication for resuturing after PK was wound dehiscence. Of these, 19 were caused by trauma, and in 10 eyes, dehiscence shortly followed suture removal. RESULTS: The interval between original PK and traumatic wound dehiscence caused by trauma ranged from 15 days to 33 years. In 5 eyes, it was >15 years. Nine eyes (47%) with traumatic dehiscence had final visual acuity better than 6/60, whereas 8 eyes (80%) with suture removal dehiscence had final visual acuity better than 6/18. Most of the dehiscence in the traumatic group was located in the inferior 2 quadrants, in contrast to temporally in the postsuture removal group. The time interval between PK and suture removal in the postsuture removal group was 16 +/- 4 months, and 7 (70%) patients had a continuous suture. Post-suture removal dehiscence was more common when corneal edema was the indication for grafting. CONCLUSIONS: Eyes with traumatic wound dehiscence have worse visual outcome than those with dehiscence after suture removal. Patients should be cautioned about the risks and consequences of wound dehiscence. The suture may be left in place longer in older patients or when corneal edema is the indication for grafting.     

Schwerwiegende Wund- und Nahtinsuffizienzen nach perforierender Keratoplastik

BACKGROUND: With regard to penetrating keratoplasty methods to culture corneal donor tissues, microsurgical techniques, HLA typing and understanding of basic mechanisms in inflammation and especially graft rejection, and postoperative treatment schedules have been improved in recent years. This now enables successful penetrating keratoplasty in many more patients than previously performed. However, in rare cases relevant problems in wound closure may appear. PATIENTS AND METHODS: A standardized treatment protocol was applied to 1,253 penetrating keratoplasties performed in a single center. Patients were continuously followed up. Simple leakage after corneal grafting was not further analyzed if conservative treatment or additional sutures achieved sufficient wound closure. In 21 cases, however, the causes of large wound dehiscence after corneal grafting were analyzed. RESULTS: During the first week early problems in suturing penetrating keratoplasty in five patients were associated with the instability of the recipients' corneal stroma (stromal thinning in keratoconus or corneal herpes, suture problems in keratomalacia, active herpes keratitis, corneal burns, or rheumatic diseases). Long-term complications in 16 patients were associated with alcoholism, herpes keratitis, rheumatic disorders or traumatic suture defects. Overall, nine patients lost functionally or even anatomically one eye because of wound dehiscence after corneal grafting. CONCLUSIONS: When penetrating keratoplasty is indicated, special attention should be given to (1) the compliance of the patient, (2) sufficient treatment of herpes keratitis or other infections, (3) adequate immunosuppression in autoimmune corneal inflammation, (4) double running continuous sutures as primary suture with sometimes additional single sutures to stabilize the graft, and (5) surgery in time.     

Fornix-based trabeculectomy using the 'anchoring' corneal suture technique

Aim: To assess the safety and efficacy of fornix‐based tra­beculectomy with the ‘anchoring’ corneal suture technique in Chinese patients. Methods: A retrospective non‐comparative case series of 66 eyes of 63 Chinese patients who underwent fornix‐based trabeculectomy combined with intraoperative mitomycin C (MMC) 0.4 mg/mL for 2?5 min were studied. Conjunctival wound closure of all eyes was with the anchoring corneal suture technique using a 9?0 nylon suture to prevent leakage at the corneolimbal interface. The success rate, with or without anti‐glaucoma medication, the complication rate and the longevity of the drainage blebs were analyzed. Results: At a mean follow‐up period of 447.36 ± 337.98 days, the mean intraocular pressure decreased from 26.83 ± 7.90 mmHg to 17.74 ± 8.74 mmHg (P < 0.001). The mean glaucoma medication decreased from 2.95 ± 0.98 preoperatively to 1.23 ± 1.41 postoperatively (P < 0.001). Thirty‐one eyes (47.0%) required no anti‐glaucoma medication postoperatively. Twenty eyes (30.3%) had qualified success postoperatively. Eight eyes (12.1%) had early wound leakage that resolved with conservative treatment. Three eyes (4.5%) required surgical repair. One eye (1.5%) had hypotonous maculopathy. No other major complications were encountered. Conclusion: Fornix‐based trabeculectomy with adjunctive mitomycin C employing the anchoring corneal suture technique appears to be both safe and effective in Chinese patients.     

Spontaneous wound dehiscence after removal of single continuous penetrating keratoplasty suture

PURPOSE: To determine the incidence and complications of spontaneous wound dehiscence after removal of a single continuous penetrating keratoplasty (PK) suture. DESIGN: Retrospective consecutive, noncomparative interventional case series. METHODS: Retrospective review of 324 consecutive continuous suture PKs performed between 1992 and 1999. RESULTS: Sixty-nine (21.3%) of 324 PKs reviewed had the continuous suture removed. The average interval for suture removal after PK was 24.5 +/- 15 months (range, 2.8-63.3 months). Five of the 69 eyes (7.2%) developed spontaneous wound dehiscence without direct eye trauma. In the five eyes that developed wound dehiscence, the continuous suture was removed at 24.6 +/- 10.3 months (range, 14-42 months). Dehiscence occurred at 11.6 +/- 6.5 (range, 3-18) days after suture removal. Significant history associated with wound dehiscence included coughing, yawning, falling without trauma to the eye, and spontaneous wound separation. The reasons for suture removal were astigmatism in four of five (80%) patients and a broken suture in one of the five patients. In four of five (80%) patients, the location of wound dehiscence correlated with the steep axis of corneal keratometry before suture removal. Surgical intervention preserved the presuture removal best-corrected visual acuity in four of the five eyes. No eyes with an intact suture spontaneously dehisced. CONCLUSIONS: The rate of spontaneous wound dehiscence after removal of a continuous suture in our series was 7.2%. All spontaneous dehiscences occurred within 2 weeks after suture removal. Older patients, who had PK for corneal edema with postoperative astigmatism and have been using corticosteroids drops for prolonged periods of time, are at higher risk of wound dehiscence. Patients should be monitored closely during the first 2 weeks after removal of a continuous suture for signs of wound separation, especially when suture removal is performed for astigmatism. Patients should be cautioned about the risk and symptoms of wound dehiscence before suture removal to facilitate early recognition and intervention for preservation of best visual potential.     

Intracorneal ring segments for correction of myopia. Results of microsurgery technique

Background and objective. Since May 1998, small incision instruments for the implantation of intrastromal corneal ring segments (ICRS) are available enabling incisions only 1.2 mm in width instead of 1.8 mm to be made. After a follow-up period of 22 months in the conventional group and 8 months in the small incision group, the results of both groups were compared. Patients and methods. Since April 1997, 73 intrastromal corneal ring segments have been implanted, the first 43 ICRS implantations in 29 patients were performed using the conventional technique, the next 30 ICRS implantations in 22 patients were performed with the small incision technique. The average preoperative myopia was ?3.5 D. Results. After 6 months, 66.7% of the patients of both groups achieved the refraction target ±0.5 D. Even on the first postoperative day, the final refraction is achieved and shows stability for 1 year without regression. After 6 months, 80% of the conventionally operated patients and 77.8% of the patients operated on with the small incision technique showed an uncorrected visual acuity of 1.0 or better. With the small incision technique the preparation of the corneal dissection channel in 2/3 corneal stromal depth is significantly easier and can be carried out more safely.. Perforations towards the inner or outer surface of the cornea can be practically excluded. Due to the smaller superficial wound in contrast to the conventional technique, a corneal suture is not necessary. Stromal depth of implantation was more than 50% and in both groups no decentration of 1.0 mm or more occurred. Conclusions. The small incision technique increases the intraoperative safety in the dissection of the stromal lamellae in the correct level. Both techniques are comparable with regards to visual acuity and refraction. The smaller corneal wound does not need a corneal suture. Because of these advantages we have completely switched our technique to the small incisions.     

Deep versus appositional suturing of the scleral pocket incision for astigmatic control in cataract surgery

A study was performed to determine whether alternative suturing techniques of a standard wound play a significant role in the immediate and long-term postoperative course of corneal astigmatism. Two groups of patients had phacoemulsification and posterior chamber lens implantation through a scleral pocket incision closed with a continuous suture. In one group, the sutures were apposed to the posterior edge of the scleral incision; in the second group, deep suture placement designed to incorporate the internal layer of the scleral pocket was used. The deep suture group demonstrated significantly reduced transient iatrogenic astigmatism but the eventual healed astigmatic results were similar for the two groups. The deep suture group developed no filtration blebs; these did occur in three of 50 cases sutured with the appositional technique.     

Fibrin glue in ophthalmology

Suturing is a time consuming task in ophthalmology and suture induced irritation and redness are frequent problems. Postoperative wound infection and corneal graft rejection are examples of possible suture related complications. To prevent these complications, ophthalmic surgeons are switching to sutureless surgery. A number of recent developments have established tissue adhesives like cyanoacrylate glue and fibrin glue as attractive alternatives to sutures. A possible and promising new application for tissue adhesives is to provide a platform for tissue engineering. Currently, tissue glue is being used for conjunctival closure following pterygium and strabismus surgery, forniceal reconstruction surgery, amniotic membrane transplantation, lamellar corneal grafting, closure of corneal perforations and descematoceles, management of conjunctival wound leaks after trabeculectomy, lid surgery, adnexal surgery and as a hemostat to minimise bleeding. The purpose of this review is to discuss the currently available information on fibrin glue.     

Keratoplastik: Lamellieren oder perforieren?

A number of corneal disorders sooner or later call for a decision as to whether corneal grafting is necessary. The problems of the current gold standard treatment, conventional penetrating keratoplasty (PKP), have yet to be fully solved, namely accelerated postoperative endothelial cell loss, endothelial immune reactions and the induction of astigmatism, which depends among other things on the trephination technique used. The use of a hand trephine may lead to different cutting angles between donor and recipient, resulting in increased postoperative astigmatism. This technique is therefore now only used for certain indications. One major advantage of mechanically guided trephine systems, which are now considered standard, is the possibility of trephining the donor disc from the epithelial side to avoid donor oversizing, therefore reducing postoperative astigmatism. Even less astigmatism is induced in keratoconus patients using an Excimer laser for trephination, as this technique does not lead to corneal deformation during trephination. Furthermore, this non-contact method can also be used to trephine unstable corneas. Femtosecond lasers allow the creation not only of straight but also profiled trephination edges, leading to more stable wound healing and hence earlier suture removal.     

屈光性缝合在角膜穿孔伤中的应用

目的探讨应用显微技术及黏弹剂行角膜穿孔伤的屈光性闭合性缝合的临床意义和价值。方法59例（59眼）不同程度的角膜穿孔伤,通过显微技术及黏弹剂的屈光性闭合性缝合,观察临床疗效。结果全部病例伤口均甲级愈合。手术均无严重并发症,视力与术前比较有明显提高。结论屈光性闭合性缝合使角膜形成良好的解剖对位,促进伤口愈合,减少术后散光,提高手术质量,对角膜穿孔伤的预合和功能恢复具有实用价值。