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In 2004, it was the first time that Wollensak and Spoerl had applied physical and chemical cross-linking methods to scleral tissue. They found that the biomechanical strength of cross-linked sclera, induced by riboflavin/ultraviolet A, glyceraldehyde and glutaraldehyde, could be improved and proposed that scleral collagen cross-linking is expected to be a new method for the treatment of pathologic myopia. In recent years, a series of explorations have been made on the effectiveness and adverse reactions of physical and chemical cross-linking in the prevention and treatment of pathologic myopia, including the establishment of various animal models and different myopia modeling methods, the improvement of cross-linking methods, the amelioration of the measurement of biomechanical strength of scleral tissue and the attention of biological parameters such as the thickness of retinal nerve fiber layer and the amplitude of electroretinogram in vivo. Genipin-crosslinking of the scleral collagen combined with posterior scleral contraction/reinforcement has been applied to clinical research. This review summarizes physical cross-linking and the genipin-crosslinking of scleral collagen to explore the effectiveness and safety of the methods in the prevention and treatment of the pathologic myopia.
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Due to the high incidence and the earlier onset age, high myopia has become an important public health problem in China. Posterior scleral reinforcement surgery has been developed for over 60 years in order to control the rapid progression and complications of high myopia. By suturing a certain size of material on the surface of the posterior eyeball, thickness and elasticity modulus of the local sclera significantly increase. As the result, the rapid growth of the axial length and the chorioretinopathy could be alleviated. At present, controversies about its clinical efficacy and safety still exist, so posterior scleral reinforcement surgery has not been widely carried out all over the world. An in-depth analysis of the mechanism, surgical manipulations and materials, the clinical application status of posterior scleral reinforcement surgery on control of high myopia can provide a basis for further standardized application of this surgery
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Pathological myopia, characterized by progressive elongation of the axial length and formation of posterior staphyloma, is accompanied by chorioretinal irreversible degeneration. It is also the focus and biggest challenge of myopia control and blindness prevention. For managing progressive early-onset pathologic myopia and myopic traction maculopathy, episcleral pressurization of macula is a practical option. It can be divided into posterior scleral reinforcement surgery and macular buckling surgery according to the presence or absence of operative top pressure ridge after surgery, both of which are different in terms of implanted materials, procedures and indications. The implanted materials, procedures and indications are different between the two. Under the background of soaring prevalence of myopia, it is necessary to modify and cautiously popularize the techniques of episcleral pressurization of macula to provide high level clinical evidence for management of pathological myopia.
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Myopia is a common eye disease, and pathological myopia is mainly caused by abnormal axial elongation.The weakening of scleral biomechanics is one of the important characteristics of pathological myopia.In recent years, preventing the growth of the eyeball through strengthening the posterior sclera and improving the scleral stiffness has become a primary method to treat pathological myopia.Direct enhancement of scleral stiffness by scleral cross-linking is a new treatment under study, and the main methods of it include scleral collagen crosslinking induced by the photosensitizer riboflavin and ultraviolet-A irradiation, and induced by chemical reagent.People with myopia, especially high myopia, are more likely to suffer from primary open angle glaucoma.Glaucoma and myopia in the early stage are similar in clinical manifestations as well as the pathogenesis, which can promote and influence each other.There are some similarities in strengthening sclera, improving the scleral biomechanical properties, reducing axial elongation and scleral deformation in the treatment of the two diseases.Whether scleral cross-linking can be used as a new treatment of glaucoma and to reduce retinal ganglion cells damage has become a new research hotspot.In this article, the research progress in scleral cross-linking for the treatment of myopia and glaucoma were summarized, and the existing disputes were discussed in order to analyze the future of scleral cross-linking therapy.
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@#AIM:To evaluate the clinical effect of the auxiliary application of posterior scleral reinforcement(PSR)in the vitrectomy of macular hole retinal detachment with over-long axial length.<p>METHODS:A clinical randomized controlled trial was conducted. Patients of macular hole retinal detachment with over-long axial length ≥29mm were randomly divided into two groups. Group A accepted PSR + PPV + silicone oil injection, group B accepted PPV + silicone oil injection. After followed-up one year, the BCVA, the percentage of macular hole closure, cure rate of retinal detachment and reoperation rate were analyzed.<p>RESULTS:Totally 46 eyes were included in the study. The average BCVA of the two groups after treatment was improved. The BCVA of group A changed from 1.61±0.02 to 0.85±0.22(<i>t</i>=10.36, <i>P</i><0.01), and that of group B increased from 1.59±0.04 to 1.08±0.16(<i>t</i>=7.92, <i>P</i><0.01). The improvement of group A was greater than that of group B(<i>t</i>= -2.38, <i>P</i>=0.03). There was no significant change of the axial length before and after operation in both groups(<i>P</i>>0.05). In group A, the healing rate of macular hole was 91%(21/23), and the reoperation rate was 4%(1/23)before silicone oil removal. After silicone oil removal, no patients recurred to retinal detachment. During the follow-up period, silicone oil removal was completed in all eyes. In group B, the closure rate of macular hole was 65%(15/23), the rate of reoperation before silicone oil removal was 35%(8/23), the redetachment rate after silicone oil removal was 26%(6/23), and the rate of the silicone oil removal throughout the follow-up period was 74%(17/23).<p>CONCLUSION: PSR can effectively improve the successful rate of pathological myopic macular holes with retinal detachment and reduce the recurrence and reoperation.
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@#Posterior scleral reinforcement surgery is a common method for the treatment for high myopia, which can strengthen the intensity of sclera and inhibit the progression of high myopia. The posterior scleral reinforcement materials are very important, including biological materials such as pericardium, donor sclera, umbilical cord, dura mater, acellular allograft dermis and so on; non biological synthetic materials such as polyester fiber, polyester mesh sponge and plasma-modified silicone graft and so on. These materials were used in the experimental animals and clinical patients, and showed obvious effect on controlling the progress of high myopia.
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AIM: To analyze the postoperative infection of pathological myopia with pocket scleral reinforcement. ·METHODS:The clinical data of 167 cases of pathological myopia treated with pocket scleral reinforcement in June to December 2014 were analyzed. The postoperative infection rate, the resistance of pathogenic bacteria were analyzed, and the related factors of infection were analyzed. ·RESULTS: A total of 286 eyes were obtained in 167 patients. The infection rate was 6. 3% in 10 patients ( 18 eyes) . There were 30 pathogenic bacteria isolated from the 18 infected eyes, in which were 10 Staphylococcus aureus, 10 Staphylococcus epidermidis, 6 Klebsiella pneumoniae, 4 Pseudomonas aeruginosa infection. Gram positive bacteria showed higher resistance to penicillin, ampicillin and ciprofloxacin, and were sensitive to vancomycin. The resistance rates of gram negative bacteria to cefotaxime were higher, but to imipenem was low. The two groups of patients age, culture level, operation time, the number of operation, intraoperative nursing staff seniority, postoperative medication compliance rate was statistically significant (P<0. 05), which related to the infection after pocket scleral reinforcement. ·CONCLUSION:The infection caused by Staphylococcus aureus is the most common after pocket scleral reinforcement, and it is sensitive to vancomycin, and gram negative bacteria is sensitive to imipenem. Shortening the operation time, using the experienced nursing staff to cooperate, reducing the number of operation and improving the compliance of the patients can reduce the postoperative infection.
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Objective To study curative efficacy of granisetron in treatment of postoperative severe vomiting after posterior scleral reinforcement . Methods 84 patients of posterior scleral reinforcement who received therapy from January 2012 to December 2014 in our hospital were selected as research objects.According to random number table,those patients were divided into the control group (n=100) and the observation group (n=100), the control group were treated with ondansetron hydrochloride at the end of surgery, while the observation group were treated with granisetron at the end of surgery.Then postoperative sedation, analgesia, nausea, vomiting and so on.were compared.Results There were no significant differences in anesthesia time, operation time and remifentanil dosage between the two groups.The Ramsay scores of the observation group were (2.49 ±0.31), (2.23 ±0.34) and (2.10 ±0.28) points at 30 min, 1h and 2h after operation, respectively.In the control group, Ramsay scores were (3.02 ±0.42), (2.84 ±0.37), (2.45 ±0.34) at 30 min, 1h and 2h after operation, lower than the control group.The incidence of nausea and vomiting in the observation group were 9.52% ( 4/32 ) , 11.90% ( 5/42 ) respectively, and there was no significant difference between the two groups in the postoperative analgesia The total incidence of postoperative nausea and vomiting was 30.95% (13/42) and 30.95% (13/42) respectively, which were lower than the control group (P <0.05).Conclusion Granisetron is well for postoperative posterior scleral reinforcement, which can reduce the incidence of postoperative severe vomiting, it’s worthy of application and promotion.
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The rate of blinding caused by high myopic maculopathy is high, vitrectomy is the most common treatment. However, the effectiveness of vitrectomy for high myopic patients who have serious posterior scleral staphyloma is not ideal. Recent years, posterior scleral reinforcement is used as a supplementary method with vitrectomy in clinical, treating for high myopic maculopathy. lt achieves a positive curative effect especially in macular foveoschisis and macular hole cases. ln this article, we introduced a review of history, current situation, material and surgery operand of scleral reinforcement. lt also makes a further discussion of its prospects used in retina surgery.
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Sclera plays an very important role in maintenance of eyeball structure and its functions. The biological and biomechanical properties of sclera is determined by the extra cellular matrix metabolism, the cytokine expression and its own biomechanical properties of scleral fibroblasts. Lots of biological and biomechanical changes in sclera and scleral fibroblasts are the concomitants in the process of myopic development and therapy. The biomechanical studies on sclera and scleral fibroblasts by Mechanics Biology coupling will enable to reveal the physiological function, pathological change and therapeutic mechanism of ocular organ and in this review, such biomechanical studies about sclera and scleral fibroblasts were summarized and discussed.
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Objective To evaluate the biomechanical properties of fibroblasts for rabbit experimental myopia after Posterior Scleral Reinforcement (PSR) treatment, and discuss the mechanism of PSR in myopia treatment as viewed from biomechanics. Method 45 rabbits of three week old were randomly monocular treated by eyelid suture to prepare experimental myopia eye. After 60 days, the experimental myopia eyes were divided into two groups randomly. Group A was treated by PSR. Group B was treated by similar operation without placing reinforce strap. After three months and six month, the fibroblasts from each group were isolated and cultured in vitro respectively. The cultured cells were then determined to be fibroblasts by using immunocyte chemistry method. Micropipette aspiration technique was used to investigate the viscoelastic properties of the fibroblasts from each group with mechanical model of semi infinite somatic cells. ResultsThree months after operation, the viscoelastic properties of the scleral fibroblasts in Group A and Group B exhibit no significant difference (P>0.05) three months and six months as well (P>0.05) after operation with the equilibrium modulus, E∞, and apparent viscosity, μ of the scleral fibroblasts in Group A (E = (361.2± 121.1)Pa、μ=(2928.2±669.4)Pa·s) compared with that in Group B (E =(347.6± 82.1)Pa、μ=(2820.6± 593.5)Pa·s). Neither in Group A nor Group B, the E∞ and μ at different stages after operation have significant difference (P>0.05). The E∞ and μ in transition zone tissues at different stages after operation have no significant difference(P>0.05) either. Conclusions The enhancement of PSR is caused by transition zone tissues and the strip itself.