Complications of glaucoma drainage implant surgery

Glaucoma drainage implants play an important role in the management of refractory glaucoma. It may be considered as a primary procedure in eyes with severe scarring of the conjunctiva and the limbus, neovascularization, multiple previous, failed filtering procedures, and severely glaucomatous eyes for which corneal graft is planned. Recommendations have been made regarding improving the biocompatibility of the materials used in the manufacture of these implants. The current state of development of glaucoma drainage implants is likened to that of intraocular lenses in the 1970s. Further development of devices and techniques will only serve to improve our armamentarium and success against glaucoma, specifically refractory glaucoma. Glaucoma posterior tube shunts have proved to be safe, with the majority of complications either nonsight-threatening, spontaneously resolving, or reversible. Considered primarily in the most severe cases of refractory glaucoma, it has otherwise changed the outlook for such patients.     

Recent developments in glaucoma drainage implant surgery

Refractory glaucoma remains a challenging problem for the ophthalmologist. Drainage implant surgery is a valuable and effective option for its treatment. Recent developments in implant design and surgical technique have decreased the incidence and severity of postoperative complications while increasing the efficacy of glaucoma drainage implant devices.     

Ahmed valve drainage implant surgery in the management of paediatric aphakic glaucoma

BACKGROUND: Paediatric aphakic glaucoma presents months or years after cataract surgery in children and is a major long term complication. The results of surgical treatment are poor and many children require multiple and repeat procedures with poor visual outcomes. METHODS: 13 children (19 eyes) had Ahmed valve implantation surgery, nine of the children had previous procedures such as cycloablation or trabeculectomy. Mitomycin was used at surgery in some patients and valve needling with Healon GV and 5-fluorouracil in some blebs after surgery. SF(6) gas was also used at the time of surgery in most children to reform the anterior chamber. RESULTS: 12 of the children (18 eyes) achieved intraocular pressure control of 15 mm Hg or less with a valve alone or with additional medical therapy. CONCLUSION: Ahmed valve implantation surgery alone or in combination with medical therapy is successful and safe in the management of paediatric aphakic glaucoma.     

Outcomes of inferonasal Baerveldt glaucoma drainage implant surgery

PURPOSE: To determine the outcomes of inferonasal Baerveldt glaucoma implant (BGI) surgery. PATIENTS AND METHODS: A retrospective, non-comparative case series of 182 eyes of 182 patients who underwent inferonasal placement of a Baerveldt glaucoma implant. The main outcome measures included intraocular pressure, number of glaucoma medications, best corrected visual acuity, and complications. RESULTS: Patients were followed for an average (+/- SD) of 19 +/- 15 months. Median Snellen visual acuity was unchanged at last follow-up. Intraocular pressure was reduced from a mean (+/- SD) of 28.6 +/- 11.5 mm Hg preoperatively to 13.4 +/- 5.7 mm Hg at most recent follow-up (P < 0.001). The number of antiglaucoma medications was reduced from a mean (+/- SD) of 2.7 +/- 1.3 preoperatively to 1.1 +/- 1.1 at most recent follow-up. Nineteen eyes met our criteria for failure, yielding a cumulative percent survival of 92% at 12 months, 88% at 24 months, and 77% at 44 months. The most common complications were hyphema (14 eyes, 8%), choroidal effusion (12 eyes, 7%), and corneal decompensation (19 eyes, 10%). Endophthalmitis and diplopia occurred rarely (1 eye, <1%; 3 eyes, 2%, respectively). CONCLUSIONS: Inferonasal Baerveldt glaucoma implant placement appears to be a safe and effective surgical option that may be helpful in certain clinical situations.     

Ultrasound biomicroscopy diagnosis of congenital glaucoma

BACKGROUND: In children with congenital glaucoma the assessment of the anterior chamber and the chamber angle might be difficult since scarring and opacities of the cornea are often seen. The purpose of our study was to reveal in vivo--morphology of the anterior segment in patients with congenital glaucoma and opaque cornea. PATIENTS AND METHODS: In 46 eyes of 23 children with different degrees of corneal opacities we performed ultrasoundbiomicroscopy (UBM) of the anterior chamber after having performed a complete ophthalmological examination in general anesthesia. RESULTS: Massive abnormalities of the anterior segment morphology were detected in 5 eyes with completely cloudy cornea. In eyes with partial opacity of the cornea, UBM gave additional information concerning the anterior chamber angle topography, as iris remnants in aniridia, or anterior synechia. CONCLUSION: Especially in cases with extensive corneal opacities the UBM allows us to get morphological and topographic information about the anterior segment and helps to establish an individual strategy for surgical management.     

Long-term results of non-valved Glaucoma drainage implant surgery and glaucoma drainage implant combined with trabeculectomy

Purpose:

The purpose was to investigate the efficacy and complications of nonvalved glaucoma drainage implant (GDI) surgery and GDI combined with trabeculectomy.

Subjects and Methods:

Serial Japanese patients who received GDI were retrospectively investigated. The survival rate of eyes was analyzed using the Kaplan-Meier method, defining death as: (1) Intraocular pressure (IOP) <6 mmHg, or ≥22 mmHg, and <20% reduction of preoperative IOP, (2) additional glaucoma surgery, (3) loss of light perception. Prognostic factors of age, sex, previous surgery, type of glaucoma, synechial closure, preoperative IOP, type of GDI (single-, double-plate Molteno, Baerveldt 350) and GDI combined with trabeculectomy were investigated employing proportional hazards analysis.

Results:

One hundred and twenty-four eyes of 109 patients aged 53.3 ± 7.8 years old were analyzed. Types of GDI were single-plate (15.3%), double-plate Molteno (71.8%), and Baerveldt 350 (12.9%). The results of survival rate analysis were 86.1, 71.1, 71.1, and 64.6% for 1, 3, 5, and 10 years respectively. Thirty-four eyes (27.4%) died because of uncontrolled IOP (19.4%), loss of light perception (5.6%), and additional glaucoma surgery (2.4%). Single-plate Molteno was the only risk factor for failure. Persistent unphysiological hypotony (0.8%) and bullous keratopathy (5.6%) were observed.

Conclusion:

Nonvalved GDI surgery and GDI combined with trabeculectomy using nonabsorbable tube ligature proved to be an excellent device for any type of glaucoma in Japanese patients. Hypotony and corneal endothelial loss are the most serious complication in the long-term results of our patients.     

Ultrasound biomicroscopy of residual vitreous base after vitreoretinal surgery

Residual vitreous base after vitreoretinal surgery was evaluated by ultrasound biomicroscopy (UBM). Twenty aphakic and pseudoaphakic patients (20 eyes) undergoing surgery for different vitreoretinal diseases were evaluated by high-frequency (50 MHz), high-resolution (50 microm) UBM, performed the day before surgery, weekly up to 1 month after surgery and then monthly. One week after surgery, the vitreous remnants were 'hardly visible' in 3 cases, 'visible' in 6 cases and 'highly visible' in 11. At the end of the follow-up (2.2 months), the 'hardly visible' cases increased to 6 and the 'visible' cases to 12, while the 'highly visible' cases decreased to 2. UBM demonstrated that vitreous base remnants were present in spite of accurate surgery; a spontaneous volume reduction of vitreous was observed during the follow-up.     

原发性闭角型青光眼的超声生物测量研究

目的 应用A型眼科超声和超声生物显微镜(ultrasound biomicroscope,UBM)研究原发性闭角型青光眼(primary angle-closure glaucoma,PACG)不同瞳孔直径下眼前节和后房结构的解剖特征.方法 正常对照组24例(48眼)及PACG组24例(48眼)按照检查时瞳孔直径(d)分为以下3组:d ＜2.5 mm组,2.5 mm≤d≤4.0 mm组,d＞4.0 mm组,进行眼轴测量和UBM检查.眼轴长度采用STORZ-A型眼科超声诊断仪测量,眼前节各项参数采用Zeiss-Humphrey-840型UBM检查.结果 PACG眼较正常眼前房浅,眼轴短,小梁网虹膜夹角变小,房角开放距离缩短,睫状突高度减小,巩膜外侧面与虹膜长轴的夹角、与睫状突夹角减小.PACG眼的角膜厚度较正常眼增厚,分别为(584.208±78.210) μm、(577.583±39.681)μm,但差异无统计学意义(P＞0.05).反映瞳孔阻滞的参数虹膜晶状体接触距离差异无统计学意义(P＞0.05).PACG眼与具有正常瞳孔直径的眼相比,瞳孔直径越大,小梁网虹膜夹角越小,根部虹膜越厚,虹膜晶状体接触距离越小,而正常眼的根部虹膜厚度、小梁网虹膜夹角、虹膜晶状体接触距离与瞳孔直径无相关性.结论 PACG眼与正常眼解剖结构在任何瞳孔直径下均不同.PACG眼随瞳孔直径增大,眼前节更为拥挤,睫状体旋前增加房角关闭可能.     

Ultrasound biomicroscopy of intrascleral lake after viscocanalostomy and cataract surgery

PURPOSE: To assess anatomic changes at the sclerectomy site after combined viscocanalostomy and cataract surgery associated with POAG or OH and cataract. METHODS: In a prospective, noncomparative, longitudinal study, we performed ultrasound biomicroscopy (UBM) of the sclerectomy site in 84 eyes at 3, 6, and 12 months after the surgery. Four parameters in UBM findings (area, radial longitudinal length, height of intrascleral space, and meridional length of window) were measured and the IOP level, the number of antiglaucoma medications, and bleb formation were observed for 12 months. RESULTS: Intraocular pressure decreased from 19.8 +/- 3.5 (+/- SD) mm Hg preoperatively to 15.5 +/- 3.0 mm Hg 12 months postoperatively (P < 0.0001). Blebs were formed in 2 of 84 eyes (2.4%) at 1 month, and 1 of 84 eyes (1.2%) after 3 months. The IOP decreased at 3, 6, and 12 months postoperatively by 5.8, 4.8, and 4.3 mm Hg, respectively (P = 0.0016). A significant difference was observed between 3 months and 12 months in area (0.17 and 0.13 mm, respectively, P = 0.0127 using the Bonferroni/Dunn test), longitudinal length (0.89 and 0.72 mm, P = 0.0059), and height (0.21 and 0.15 mm, P < 0.0001), but not in meridional length (0.41 and 0.33 mm). The lake was present in 66.7% of cases at 12 months. CONCLUSION: Combined viscocanalostomy and cataract surgery lowered IOP without bleb formation. Postoperatively, the size of the lake and IOP decreased, suggesting parallel reduction of the two. The lake was undetected ultrasonographically in one third of the cases 1 year postoperatively.     

Ultrasound biomicroscopy and therapy of malignant glaucoma]

BACKGROUND: Malignant glaucoma is a rarely diagnosed condition though it has been known since over one hundred years and understood to be based on an ciliary blockage since thirty years. Now it is possible to visualise pathomechanism of ciliary block by ultrasoundbiomicroscopy. PATIENTS AND METHODS: Between January 1994 and November 1998 thirteen patients with ciliary block glaucoma had been observed. Four underwent ultrasoundbiomicroscopy. RESULTS: Ciliary block glaucoma is caused by obliteration of the posterior chamber. Ultrasoundbiomicroscopy showed, that in phakic eyes the lens, in pseudophakic eyes the capsule together with the anterior vitreous membrane and in aphakic eyes the vitreous alone are the blocking agents. Hyperopia, a narrow iridocorneal angle and ciliary sulcus as well as plateau iris configuration and a history of miotics are the predisposing risks for ciliary block glaucoma, especially after additional surgery such as cataract extraction, iridotomy, iridectomy and trabeculectomy. Clinical features are always a raised intraocular tension accompanied with a flattening of the anterior chamber, which are to be differentiated from an angle closure glaucoma. This is easy, if iridectomy, irido-capsulovitreotomy or pseudophakia are present and difficult in the very rare spontaneous cases. Cycloplegics and YAG-laser iridectomy may break the ciliary block, but the most preferable therapy is lensectomy (phakic eyes) and partial removing of the anterior vitreous and a peripheral sector of lens capsule combined with an iridectomy. This is easily performed with the vitrector via pars plana. CONCLUSIONS: Ultrasoundbiomicroscopy starts to confirm the theories on ciliary block glaucoma and allows to assess the different modes of treatment. The most successful treatment is lens extraction and partial vitreo-capsulo-iridectomy via pars plana.     

应用超声生物显微镜检查及诊断青光眼术后睫状体脱离

目的：探讨青光眼术后睫状体脱离造成浅前房的形态学改变及其临床意义。方法：应用眼科传统B超及超声生物显微镜（ultrasound biomicroscopy,UBM)对青光眼术后睫状体脱离的患眼,健眼形态进行观察并对其测量的相关数据进行统计学分析。结果：UBM对B超不能诊断的睫状体脱离和脉络膜浅脱离,能特异性地进行检查诊断,其特征性表现为：巩膜与睫状体间存在无回声区,睫状体位置前移,前旋,睫状体平坦部向眼中轴部位移动,部分患者可见睫状体平坦部呈层间分离,前房变浅的原因是睫状突向前扭转,导致虹膜根部膨隆,晶状体向前移位,所有睫状体脱离眼均为360度全周脱离,而非某一象限的脱离,不伴有脉络膜脱离的单纯睫状体脱离所致的青光眼术后浅前房,一般不致前房完全消失,保守治疗可奏效,结论：应用UBM检查可以对睫状体脱离造成的青光眼术后浅前房进行明确诊断,为临床治疗提供可靠依据。     

Ultrasound biomicroscopy of the anterior segment after congenital cataract surgery

PURPOSE: To evaluate the structure of the anterior segment after congenital cataract surgery with ultrasound biomicroscopy. METHODS: Ultrasound biomicroscopy was performed on 28 eyes of 15 patients after congenital cataract surgery (age range, 8-27 years; mean, 13.1 +/- 1.1 years), of which 26 eyes had pars plana lensectomy and two eyes had phacoemulsification and aspiration, and on 21 eyes of 11 phakic control subjects who were healthy (age range, 6-17 years; mean, 11.5 +/- 1.1 years). The angle-opening distance at 500 microm was measured on a line perpendicular to the trabecular meshwork 500 microm from the scleral spur, and the trabecular-iris angle was measured. RESULTS: Angle-opening distance at 500 microm in the congenital cataract group ranged from 174 to 920 microm (mean, 424 +/- 28 microm), and in the control group it ranged from 260 to 1,119 microm (mean, 643 +/- 57 microm), a difference that was significantly different (P =.0004, Student t test). The trabecular-iris angle in the congenital cataract group ranged from 30.4 to 66.9 degrees (mean, 41.9 +/- 1.6 degrees) and in the control group ranged from 32.1 to 69.8 degrees (mean, 44.9 +/- 2.5 degrees), a difference that was not significantly different (P =.28, Student t test). This means that there is a tendency for high insertion of the iris in the congenital cataract group, and intraocular pressure was elevated after surgery (including glaucoma and ocular hypertension) in 10 (47.6%) of 21 eyes with high insertion. The pars plicata after congenital cataract surgery was significantly flatter than that of control subjects (P =.0057, Student t test). CONCLUSIONS: Ultrasound biomicroscopy is a useful method for evaluating the anterior segment of eyes with congenital cataract, and complications after cataract surgery can be caused by disorganization of the anterior segment. Patients with abnormalities of the anterior segment should be followed up closely for the development of glaucoma.     

Ultrasound biomicroscopy images: long-term results after deep sclerectomy with collagen implant

PURPOSE: The aim of this study was to understand the long-term outflow pathway mechanisms after deep sclerectomy - when collagen implant is resorbed - using ultrasound biomicroscopy (UBM). METHODS: Forty-three eyes of 32 patients with medically uncontrolled open-angle glaucoma at least 1 year after deep sclerectomy were studied in an observational, non-randomised, consecutive case series. Postoperatively 15 eyes (35.7%) had goniopuncture with the Nd:YAG laser. Four eyes (9.5%) had postoperative subconjunctival injections of mitomycin C and two eyes (4.7%) had an injection of 5-fluorouracil, because of intraocular pressure (IOP) increase. Complete examination and UBM of the filtering site were performed 1-6 years after surgery. The following parameters were assessed: (1) Presence of a subconjunctival filtering bleb; (2) presence and volume of an intrascleral cavity; (3) presence of a suprachoroidal hypoechoic area. RESULTS: Intraocular pressure decreased significantly from 28.1+/-2.5 mmHg preoperatively to 12.4+/-3.8 (range 7-25) mmHg at the time of UBM (at least 1 year after surgery). Forty eyes showed clinically a diffuse filtering bleb. UBM demonstrated a subconjunctival space in all eyes. In 39 eyes (92.8%) an intrascleral cavity was observed. The mean volume of this cavity was 1.8 (range 0.11-6.53) mm(3). In 19 eyes (45.2%) we observed a hypoechoic area in the suprachoroidal space. CONCLUSION: UBM examination demonstrated several aqueous humour drainage pathways. A low-reflective diffuse subconjunctival space meant persistent filtration in all eyes. More than 1 year after surgery 92.8% of eyes had a remaining intrascleral cavity. In almost half of the patients an additional suprachoroidal outflow was observed, significantly correlated with a lower IOP.     

Ultrasound biomicroscopy of eyes undergoing deep sclerectomy with collagen implant.

AIMS--To assess the intraocular pressure (IOP) lowering mechanism of deep sclerectomy with collagen implant (DSCI), a non-penetrating glaucoma surgery. METHODS--Nine eyes of nine patients with medically uncontrolled open angle glaucoma underwent DSCI. Ultrasound biomicroscopy (UBM) of the sclerectomy site was performed 1 month after surgery. The following factors were assessed: length and height of collagen implant, and thickness of the residual trabeculocorneal membrane. RESULTS--Postoperative IOP decreased significantly in all nine eyes from a preoperative mean value of 25.8 (SD 4.8) mm Hg to a postoperative (1 month) mean value of 11.3 (6.3) mm Hg (p = 0.001). In all nine eyes, UBM at 1 month after surgery showed a subconjunctival filtration through the thin trabeculocorneal membrane and through the scleral flap around the collagen implant. In four cases, a hypoechoic area in the suprachoroidal space was observed and might represent ciliary body detachment or be due to suprachoroidal drainage of aqueous humour through the thin deep scleral wall. At 1 month after surgery the mean trabeculocorneal membrane thickness was 110.1 (16.8) microns, and the mean length and height of the collagen implant were 2.3 (0.1) mm and 1.1 (0.1) mm respectively. CONCLUSION--DSCI lowered IOP by allowing aqueous filtration through a thin trabeculocorneal membrane to the subconjunctival space and, eventually, to the suprachoroidal space.