Histopathology of continuous wave neodymium: yttrium aluminum garnet and diode laser contact transscleral lesions in rabbit ciliary body. A comparative study

Neodymium: yttrium aluminum garnet (Nd:YAG) laser transscleral cyclophotocoagulation has been shown to be an effective method of lowering intraocular pressure (IOP). Transmission and absorption features of diode laser radiation (810 nm) make these new laser sources suitable for production of transscleral thermal lesions. The transscleral effects on rabbit ciliary body of Nd:YAG and diode laser wavelengths were compared using a CW Nd:YAG laser and a CW Aluminum Gallium Arsenide diode laser. Both lasers were delivered by silica optic fibers, 600 microns in diameter. Eight rabbits were treated by applying the optic fiber 0.5 mm from limbus while increasing energy values from 0.2-2 J. The lesions produced at equal energy values underwent gross and histologic and ultrastructural comparison. Gross examination revealed threshold lesions at 1 J energy for the Nd:YAG laser and 0.8 J for the diode laser. The diode laser produced transscleral thermal lesions of the rabbit ciliary body comparable to those achieved by the Nd:YAG laser. The histologic and ultrastructural study showed that diode laser radiation produced more remarkable damage to the ciliary pigmented structures, causing deep coagulation necrosis of the pigmented epithelium, wide disorganization of the collagen in the stroma, and intravascular coagulation phenomena in the ciliary vessels. Before the introduction of these new laser sources in clinical transscleral procedures, further investigation is needed to determine optimal energy levels.     

Treatment parameters for the efficacy of transscleral cyclophotocoagulation in rabbits using a diode laser

PURPOSE: To determine parameters for the efficacy of transscleral cyclophotocoagulation (TSCPC) using a diode laser. METHODS: We performed TSCPC on 74 pigmented rabbits with different exposure powers and varying number of applications, followed by clinical observation and histological examination up to 24 weeks. RESULTS: Based on observation of the clinical course, the most favorable parameters were 600 mW and 36 or 48 applications, which did not cause severe complications and sufficiently lowered intraocular pressure (IOP). Histological examination revealed coagulation of the epitheliums and stroma of the ciliary body at 600 mW. The stroma of the ciliary body was severely damaged at 900 mW. CONCLUSIONS: Transscleral cyclophotocoagulation at 600 mW with a larger number of applications than previously reported did not cause severe complications and effected greater and more lasting lowering of IOP than TSCPC with more intense coagulation and fewer applications.     

国产半导体激光器治疗顽固性青光眼遥的实验研究

目的：评价国产半导体激光器的实用性,了解其对兔青光眼治疗的效果和安全性。方法：用国产半导体激光器对8例兔青光眼实施经巩膜的睫状体光凝术,术后观察其眼压及眼部变化逾3月。结果：激光术后10天起,实验组眼压即下降,有效率达100％,1月时已降至正常范围。无明显并发症,无眼球萎缩。病理检查显示光凝处睫状体上皮及基质均出现凝固性坏死,其程度与激光击射能量有关。结论：国产半导体激光器性能稳定,能有效降低兔青光眼的眼压。其临床应用价值待验证。     

Combined cataract and glaucoma surgery: endoscope-controlled erbium:YAG-laser goniotomy versus trabeculectomy

Background To compare endoscopic infrared laser trabecular ablation and trabeculectomy (both combined with cataract surgery) regarding intraocular pressure (IOP), visual acuity, antiglaucomatous drugs and complications.Methods Seventeen eyes of 14 patients [age 74.7±11.7 years (arithmetic mean ± standard deviation)]—13 with primary open-angle glaucoma (POAG) and four with pseudoexfoliation glaucoma (PEXG)—underwent standard cataract surgery. After lens implantation, a probe (1.1 mm external diameter) with optic and laser fibres and an irrigation tube was introduced through the cataract incision. To perforate Schlemms canal, 15–17 single pulses (16 mJ, 160 s) were applied using a photoablative infrared laser (Er:YAG, =2.94 m). All eyes except one received antiglaucoma treatment. The control group treated with cataract surgery and trabeculectomy consisted of 17 eyes (13 POAG, four PEXG) of 15 patients (age 75.0±5.6 years), each eye received antiglaucoma treatment.Results Mean follow-up was 3 years. The eyes treated with the endoscopic laser showed a mean preoperative IOP of 23.3±4.3 mmHg, which was reduced to 15.0±2.1 mmHg (mean IOP lowering 33.7%) after 3 years. Five eyes needed no medication for IOP-control after the procedure. Two eyes needed further surgery for IOP-control. In the control group, mean IOP was 24.5±2.6 mmHg in the beginning and 17.3±6.2 mmHg after 3 years, corresponding to a 33.3% lowering of IOP. Six eyes needed no medication, four eyes needed further surgery to lower IOP.Conclusions After 3 years follow-up of a small pilot group, combined endoscopic infrared laser surgery with cataract surgery seems to be a safe and effective way to lower IOP. It shows the same ability to lower IOP as combined cataract surgery with trabeculectomy. In addition, there are markedly less complications with the endoscope-controlled photoablative laser procedure.The authors have no proprietary interest in the techniques used. This study was presented in part at the 101st meeting of the Deutsche Ophthalmologische Gesellschaft (DOG), Berlin, 2003.     

兔眼内窥镜与经巩膜睫状体光凝术的组织病理学特点比较

目的比较内窥镜睫状体光凝术（ECP）与经巩膜睫状体光凝术（TSCP）的睫状体组织病理学改变特点,了解ECP的降眼压机制。方法取健康成年青紫蓝兔30只,选择1只眼行ECP,对侧眼行TSCP,另取2只兔为正常对照组。手术后的第1、3、5、7、14、28、42、56灭行裂隙灯及眼压测量。术后第7、14、28、42、56天分别随机抽取6只实验兔处死行组织病理学检查,光镜下观察2组光凝术后睫状体组织结构的改变以及邻近组织的损伤和炎症反应情况。结果与TSCP组相比,ECP组术后眼部炎症反应轻微但品状体混浊。ECP组术后各时间点降低眼压的幅度大于TSCP组（P〈0．01）。ECP组术后早期睫状突水肿、睫状体无色素上皮细胞破坏明显,42d后光镜下可见睫状体上皮细胞排列不规则及睫状突萎缩;TSCP组睫状突水肿、出血、结构破坏,而睫状体上皮细胞层破坏不充分,42d后可见睫状体萎缩、色素上皮和无色素上皮细胞不规则增生、巩膜变薄及睫状体基质瘢痕化。结论与TSCP相比,ECP对睫状突无色素上皮细胞的破坏更彻底,时邻近部位组织损伤轻微,但可引起品状体混浊。     

Contact transscleral ciliary body photodynamic therapy in pigmented rabbits using verteporfin and diode laser: evaluation of treatment parameters

PURPOSE: To evaluate the treatment parameters necessary for achieving ciliary body photodynamic damage, enough to significantly reduce IOP, using verteporfin and a diode laser. DESIGN: Animal study. METHODS: The right eye ciliary body of 30 pigmented rabbits was irradiated using verteporfin (Visudyne) and a diode laser. Photosensitizer dose ranged from 0.375 to 2 mg/kg. Three adjacent laser spots were applied 0.5 mm behind limbus at 12 o'clock position using a contact transscleral technique. The laser power was ranging from 10 to 70 mW and the duration of irradiation from 1 to 5 min per spot. The left eyes of the rabbits were used as controls. Animals were sacrificed 24 hours after the procedure and their eyes were evaluated by means of light and electron microscopy. A step-by-step approach was adopted with adjustment of experimental parameters according to histological findings. The end point was to identify the irradiation parameters necessary for induction of photodynamic damage while minimizing thermal damage. Subsequently, 10 more animals were used in order to verify the effectiveness of these irradiation parameters in reducing the intraocular pressure. RESULTS: The therapy parameters that led to photodynamic effect avoiding thermal damage were laser power of 25 mW, irradiation time of 3 min per spot, and verteporfin dose of 1 mg/kg. Transscleral ciliary body irradiation using these parameters resulted in vascular thrombosis of ciliary vessels and in substantial edema, resulting in separation of the two ciliary epithelium layers. These parameters were applied to 4 rabbits, resulting in a mean IOP reduction of 1.8 mmHg +/- 1.2 that lasted for 4 days. An increase of the laser power to 35 mW tested in 6 additional animals, resulted in mean IOP reduction of 2.2 mmHg +/- 1.2, lasting 6 days; some minimal thermal damage was seen with the later settings. CONCLUSION: The combination of verteporfin and 690 nm diode laser is effective for the induction of ciliary body photodynamic damage, which results in significant but temporary IOP reduction, after transscleral PDT in pigmented rabbits. With appropriate parameter selection, intraocular pressure reduction can be achieved while thermal damage is kept to a minimum.     

A model of chronic hypotony in the rabbit

• Background: Chronic hypotony is an important cause of functional failure after proliferative vitreoretinopathy (PVR) surgery even if the retina is successfully reattached. The purpose of this study was to create a relevant model of chronic hypotony in the rabbit. • Methods: Eighteen pigmented rabbits weighing 3–4 kg were used in our experiment. We performed pars plana lensectomy on 14 eyes of 14 rabbits with a fragmatome and a vitreous cutter. At the end of surgery, we injected 0.2 ml of phosphatebuffered saline containing 100000 cultured rabbit dermal fibroblasts over the epiciliary area. As a control, we performed pars plana lensectomy alone on four eyes of four rabbits. The intraocular pressure (IOP) was measured on days 7, 14, 21, 28. Two rabbits were killed on day 7 and prepared for histology. Two additional rabbits were killed on day 14, and the remaining ten rabbits were killed on day 28. • Results: All 14 eyes following lensectomy and fibroblast injection had an IOP less than 5 mm Hg on each follow-up and a mean of 2.5±0.6 mm Hg (mean±SD) on day 28. Four control eyes with lensectomy alone had an IOP of 7.5±2.1 mm Hg on day 28 (P<0.05). On gross examination, we identified a variety of pathologic changes, including the development of a fibrous translucent epiciliary membrane that caused distortion of ciliary processes, iridociliary adhesion and anterior displacement of the peripheral retina on day 28. Microscopic examination of eyes obtained on day 28 showed changes in the ciliary epithelium that included absence or atrophy of the non-pigmented ciliary epithelium, atrophy and cystic vacuolization of the pigmented ciliary epithelium, and interstitital edema of the ciliary body stroma. • Conclusion: We have created a model of chronic hypotony with epiciliary membrane using cultured fibroblasts in the rabbit. This model may be useful to help elucidate the pathophysiology of chronic hypotony and to investigate potential treatments.     

Ciliary body PDT in pigmented rabbit eyes: effect of single and repeated treatment

PURPOSE. To investigate the morphologic and hypotensive effect of contact transscleral ciliary body PDT in pigmented rabbit eyes. METHODS. The right eyes of 33 pigmented rabbits were irradiated using chloraluminum sulfonated phthalocyanine as photosensitizer and a diode laser (670 nm) as the light source. Twenty-five animals received a single treatment. Eight animals received a second treatment 13 days after the first one. Photosensitizer was administered by means of continuous intravenous infusion. Ciliary body was irradiated transsclerally by means of an optic fiber applied on the corneoscleral limbus. In all cases 14-16 laser applications were performed to cover 360 degrees of the ciliary body. Animals were followed for a maximum of 30 days by means of tonometry and biomicroscopy. Retreatments were performed using the same irradiation protocol. At the end of the follow up time animals were sacrificed and their were eyes prepared for light and electron microscopy. RESULTS. Transscleral ciliary body PDT resulted in significant but temporary reduction of IOP in all cases. The effect lasted about two weeks. Retreatment led to a new significant drop of the IOP, which lasted about two weeks again. In histological examination the initial effect was vascular thrombosis, followed by edema and disintegration of the ciliary epithelial layers. In all cases the appearance of the ciliary body had returned to normal 15 days after irradiation. CONCLUSION. Contact transscleral PDT with the treatment parameters used in this study results in significant but temporary functional and morphological alteration in pigmented rabbits ciliary body.     

Potential Mechanisms of Intraocular Pressure Reduction by Micropulse Transscleral Cyclophotocoagulation in Rabbit Eyes

PurposeTo evaluate the histological changes associated with, and the potential mechanisms of, intraocular pressure (IOP) reduction by micropulse cyclophotocoagulation (MP-CPC) in rabbit eyes.MethodsMP-CPC was performed on the right eyes of Dutch belted rabbits, whereas the left eyes served as controls. The laser power settings were 250, 500, 750, 1000, 1500, and 2000 mW, 10 seconds per sweep, 100 seconds in total. IOP, outflow facility, and uveoscleral outflow tract imaging, using a fluorescent tracer, were examined at one week after MP-CPC. Changes of morphology and protein expressions in the outflow tissues, conjunctiva, and sclera were also evaluated.ResultsSignificant reductions in IOP after MP-CPC were observed at 500 to 1000 mW (P = 0.036 and P = 0.014, respectively). The pre-MP-CPC IOP was 11.35 ± 0.41 mm Hg. At one week after surgery, the respective IOP values in the eyes treated at 500 mW and 1000 mW were 9.45 ± 0.49 mm Hg and 7.4 ± 0.27 mm Hg, respectively. Severe ciliary body damage was observed at 1500 to 2000 mW. MMP1–3 and fibronectin expression levels in the outflow tract and ciliary body were upregulated after MP-CPC. The α-smooth muscle actin (α-SMA) was upregulated at higher power levels. MP-CPC significantly increased uveoscleral outflow, whereas the outflow facility did not change. The α-SMA, collagen, and fibronectin were significantly upregulated in the subconjunctiva and sclera.ConclusionsReactive fibrotic responses were observed in the outflow tract, conjunctiva, and sclera after MP-CPC. A potential mechanism of IOP reduction by MP-CPC in pigmented rabbit eyes may involve increased uveoscleral outflow related to MMP upregulation.     

Selective Laser Trabeculoplasty for Medically Uncontrolled Pseudoexfoliation Glaucoma in Korean Patients

PurposeThis study investigated the efficacy and safety of selective laser trabeculoplasty (SLT) in Korean patients with medically uncontrolled pseudoexfoliation glaucoma (PEXG).MethodsThis retrospective observational study enrolled 43 medically uncontrolled PEXG patients who underwent a 360° SLT and were followed up for at least 12 months after SLT. The intraocular pressure (IOP) before and after SLT at 1 week, 1, 3, 6, and 12 months was evaluated. Treatment success was defined as an IOP reduction of ≥20% from the baseline and an IOP equal to lower than 22 mmHg without additional anti-glaucomatous intervention. Additionally, every follow-up medical record was reviewed to assess any possible side effects of SLT.ResultsBased on the Kaplan-Meier survival analysis, the treatment success rate at 12 months after SLT was 41.9% (18 eyes). For the success group at the 12 months follow-up, SLT showed a mean IOP reduction of 10.3 ± 5.0 mmHg (from 25.6 ± 4.4 to 15.2 ± 2.9 mmHg; 39.3%, p < 0.05). Among the 25 eyes that were considered as the treatment failure group, 14 eyes underwent glaucoma filtering surgeries, four eyes received additional SLT, and further intervention and follow-up was refused for seven eyes. During the overall follow-up period, there were no significant adverse events.ConclusionsSLT is a partially effective and safe procedure for lowering IOP in Korean patients with medically refractory PEXG. Therefore, it can be considered as one of the alternative treatment modalities in patients who are at high risk for conventional filtering surgery.     

A model of chronic hypotony in the rabbit

• Background: Chronic hypotony is an important cause of functional failure after proliferative vitreoretinopathy (PVR) surgery even if the retina is successfully reattached. The purpose of this study was to create a relevant model of chronic hypotony in the rabbit. • Methods: Eighteen pigmented rabbits weighing 3–4 kg were used in our experiment. We performed pars plana lensectomy on 14 eyes of 14 rabbits with a fragmatome and a vitreous cutter. At the end of surgery, we injected 0.2 ml of phosphate- buffered saline containing 100000 cultured rabbit dermal fibroblasts over the epiciliary area. As a control, we performed pars plana lensectomy alone on four eyes of four rabbits. The intraocular pressure (IOP) was measured on days 7, 14, 21, 28. Two rabbits were killed on day 7 and prepared for histology. Two additional rabbits were killed on day 14, and the remaining ten rabbits were killed on day 28. • Results: All 14 eyes following lensectomy and fibroblast injection had an IOP less than 5 mm Hg on each follow-up and a mean of 2.5±0.6 mm Hg (mean±SD) on day 28. Four control eyes with lensectomy alone had an IOP of 7.5±2.1 mm Hg on day 28 (P<0.05). On gross examination, we identified a variety of pathologic changes, including the development of a fibrous translucent epiciliary membrane that caused distortion of ciliary processes, iridociliary adhesion and anterior displacement of the peripheral retina on day 28. Microscopic examination of eyes obtained on day 28 showed changes in the ciliary epithelium that included absence or atrophy of the non-pigmented ciliary epithelium, atrophy and cystic vacuolization of the pigmented ciliary epithelium, and interstitital edema of the ciliary body stroma. • Conclusion: We have created a model of chronic hypotony with epiciliary membrane using cultured fibroblasts in the rabbit. This model may be useful to help elucidate the pathophysiology of chronic hypotony and to investigate potential treatments. Received: 3 January 1997 Revised version received: 23 May 1997 Accepted: 1 July 1997     

Surgical site characteristics after CLASS followed by ultrasound biomicroscopy and clinical grading scale: a 2-year follow-up

ObjectiveThis study describes the imaging of the filtering area in CO₂ laser-assisted sclerectomy surgery (CLASS) using ultrasound biomicroscopy (UBM) combined with the Indiana Bleb Appearance Grading Scale (IBAGS) and evaluates the mechanism by which CLASS lowers the intraocular pressure (IOP).MethodsTwenty-eight cases (28 eyes) of primary open-angle glaucoma that could not be controlled by drugs underwent CLASS. At 1, 3, 6, 12, 18, and 24 months after surgery, IBAGS was used to evaluate the external morphology of the filtering blebs, and UBM was used to describe and measure their internal structure.ResultsDuring the early period after CLASS, most cases showed diffuse filtering blebs with a serious degree of congestion. At the end of follow-up, most cases did not present filtering blebs. All patients showed an intact and thin trabeculodescemetic membrane (TDM) with an average thickness of 0.094 ± 0.017 mm. The scleral reservoir size gradually decreased over time and tended to stabilize after 18 months. At 3 and 6 months after surgery, 53.57% of the patients had abnormalities in the TDM area, and after laser goniopuncture treatment, the scleral reservoir became slightly larger and the IOP decreased. The TDM thickness was not correlated with postoperative IOP, and the scleral reservoir size was negatively correlated with IOP.ConclusionDuring the early phase after CLASS, the subconjunctival and suprachoroidal pathways may be the main mechanisms lowering IOP; over time, internal drainage pathways such as the intrascleral, trabecular-meshwork, and suprachoroidal pathways play greater roles in lowering IOP.Subject terms: Glaucoma, Outcomes research, Eye manifestations     

巩膜单通道睫状突眼内光凝治疗无晶状体青光眼

目的探讨直视下行巩膜单一通道睫状突眼内激光光凝治疗无晶状体眼青光眼的疗效。方法对28例（28眼）无晶状体眼性青光眼作11点位扁平部巩膜穿刺口,3点位透明角膜缘做眼内灌注,术中将810nm、0．5w二极管激光导管经平坦部切口插入,结合巩膜外顶压,根据术前眼压情况选择显微镜直视下进行90°～200°范围光凝。术后观察视力、眼压、眼内组织反应等,平均随访时间8个月。结果术后眼压逐渐下降,与术前眼压（42．34±7．55）术后最后1次随访眼压（18．34±1．92）mmHg比较,差异有统计学意义（F=63．71,P=0．011〈0．05）。结论经巩膜单通道行眼内光凝睫状突治疗无晶状体眼青光眼能有效地降低眼压,减少了并发症。     

经巩膜睫状体光凝治疗难治性青光眼的临床观察

目的:评价半导体激光经巩膜睫状体光凝术治疗难治性青光眼的效果。方法:回顾性分析55例56眼难治性青光眼的临床资料,均行睫状体光凝,术后随访观察并记录眼压、视力、眼部自觉症状以及并发症,随访时间3mo以上。结果:术前平均眼压53.5±18.7mmHg,末次随访平均眼压为19.4±9.6mmHg,术后眼压与术前眼压相比,差别具有统计学意义(P<0.01)。术后44眼视力无变化,2眼视力提高,10眼视力下降;眼痛均消失或缓解;并发症少,主要有葡萄膜炎、前房出血等。结论:睫状体光凝能有效降低难治性青光眼患者的眼压,且并发症少。     

不同点数半导体二极管激光经巩膜睫状体光凝对兔眼压影响的实验研究

目的研究不同点数半导体二极管激光睫状体光凝对兔眼压的影响及其病理变化。方法用波长为810nm半导体二极管激光对2组灰兔进行睫状体光凝,采用相同的能量不同的点数,并设一组对照,记录4周的眼压变化情况及不良反应,4周后取兔眼标本做睫状体的病理切片。结果光凝后2组灰兔的眼压均下降,随时间的增加,眼压有所回升,2组灰兔术前术后眼压变化值比较差异有统计学意义(P<0.01),光凝后睫状体的病理变化主要为睫状上皮的破坏和睫状体基质血管的充血及出血,并且激光的点数越多,对睫状体的破坏程度越严重。结论半导体二极管激光睫状体光凝的降眼压效果和激光击射的点数有关,不同点数的激光对睫状体有不同程度的破坏作用。     

眼内窥镜下睫状体光凝的组织病理学研究

目的 探讨眼内窥镜下睫状体光凝后兔眼睫状体细胞的变化发展过程，为临床研究提供参考资料。方法取20只青紫蓝兔进行眼内窥镜下睫状体光凝，在光凝后即刻、3d、1周、1个月和3个月光镜和透射电镜观察睫状突的结构变化过程。结果光凝后即刻睫状突组织破坏，基质血管扩张。以后组织破坏加重并出现上皮囊肿。随时问推移，睫状体组织结构紊乱，有形成分减少。结论眼内窥镜下睫状体光凝可有效地破坏睫状突结构，并使这种破坏呈不可逆。安全性好，对周围组织无破坏，是一种较为理想的青光眼治疗方法。     

Refractory glaucoma – tube or diode?

BACKGROUND: The aim of the present study was to assess the relative effectiveness of tube surgery and cyclodiode laser in terms of achieving intraocular pressure control. METHODS: A retrospective study was undertaken to compare patients undergoing double plate Molteno tube implantation with patients undergoing diode cyclophotocoagulation. Intraocular pressure (IOP) was documented at 7 days prior to surgery and postoperatively at various time points. Surgical success was defined as a final IOP between 6 (inclusive) and 21 mmHg (inclusive), without the use of topical medication, while 'qualified' success was defined as IOP within the same range with the use of topical medication. RESULTS: Twenty-eight diode patients and 26 tube patients were included for the study. An average follow up of 150 weeks (range = 21-322 weeks) was available. Mean preoperative IOP was 37 +/- 12 mmHg for the tube group and 39 +/- 16 mmHg for the diode group (t = 0.51, P = 0.61). The final IOP was 17 +/- 12 mmHg for the tube group and 21 +/- 13 mmHg for the diode group (t = 0.35, P = 0.73). Surgical success was achieved in 46% of tube eyes and 11% of diode eyes, while qualified success was achieved in 81% of tube eyes compared with 64% of eyes in the diode group. Two eyes which underwent diode became phthisical. CONCLUSIONS: IOP control may be achieved in a greater number of patients with tube surgery. The possible benefits of IOP control in diode patients need to be weighed against the risks of long-term visual loss and the need for multiple re-treatments in this group.     

国产半导体激光对兔睫状体的病理影响

目的：探讨国产半导体激光对兔睫状体的病理学改变。方法：用国产半导体激光对正常兔眼作经巩膜睫状体光凝术后，在光镜，电镜下观察其组织反应，结果：组织病理学检显示光凝处睫状体上皮及间质均出现凝固性坏死，程度与激光击射能量有关，击射区外未发现相似变化，结论：形态学结果提示国产半导体激光对击射区睫状体有破坏作用，对周围组织无影响。     

Application of hyaluronidase after unsuccessful trabeculectomy

Trabeculectomy fails to control the intraocular pressure (IOP) adequately in some cases. The effect of the enzyme hyaluronidase - 300IU Hylase Dessau (commercially available ampuls) - applied in subconjunctival injection in the region above the filtering bleb in case of postoperative rise in IOP following trabeculectomy was studied. Successful IOP control was defined as an IOP below or equal to 20 mmHg with or without medication. The investigation concerned 62 eyes (46 patients) with primary open angle glaucoma (POAG) divided in three groups: Group I - 39 eyes with early postoperative rise in IOP (7–20 days postoperatively), group II - 15 eyes with late rise in IOP (6 months–1 year after surgery), group III - 8 eyes with one previous unsuccessful trabeculectomy. In all examined cases IOP was over 20 mmHg (mean IOP was 26.23 ± 3.46 mmHg) postoperatively before application of hyaluronidase. The follow up period ranged from 6 to 34 months. We found statistically significant lowering in IOP in group I (p < 0.01), group II (p < 0.05) and group III (p < 0.05). Complications related to the use of hyaluronidase were not observed up to now. Postoperative subconjuctival injection of hyaluronidase appears to improve the prognosis following unsuccessful trabeculectomy in POAG patients.     

玻璃体切割术后早期高眼压的UBM临床观察

目的 通过超声生物显微镜（UBM）对玻璃体切割手术前后患眼进行检测比较,探讨玻璃体切割术后早期高眼压的发病机制。方法 应用UBM观察玻璃体切割手术前后患者眼前节结构的变化,分别比较有晶状体组、人工晶状体组术前术后各测量参数的变化。结果 高眼压组术后瞳孔阻滞,睫状体全周脱离、水肿、前旋。参数测量：有晶状体组的高眼压组与正常眼压组前房深度相比差异有统计学意义（t=2.000,P=0.049）,房角开放距离500高眼压组与正常眼压组相比差异有统计学意义（t=2.069,P=0.050）。人工晶状体组的高眼压组与正常眼压组前房深度相比有统计学意义（t=2.066,P=0.050）,高眼压组与正常眼压组睫状体厚度比较差异有统计学意义（t=1.926,P=0.037）。结论 术后睫状体水肿前旋致前房变浅、房角变窄,导致眼压升高,参数测量提示有晶状体高眼压组术后较术前有前房变浅、房角开放程度减小的趋势。