Are there filtering blebs after canaloplasty?

PURPOSE: Aim of the study was to assess the development of filtering blebs after canaloplasty. METHODS: Twenty eyes of 20 consecutive patients receiving canaloplasty were included. All eyes were examined clinically (slit lamp), and by anterior segment optical coherence tomography and high-frequency ultrasound biomicroscopy to detect filtering blebs. Preoperative and postoperative intraocular pressure (IOP) and medications were recorded. No antimetabolites were used at any time. Two success criteria were defined to assess a possible correlation of bleb formation and success: (1) IOP ≤21 mm Hg and minimum 20% IOP reduction without medication and (2) IOP <18 mm Hg without medication. RESULTS: No filtering blebs were detected clinically. One patient had a filtering bleb-like structure as detected by anterior segment optical coherence tomography and ultrasound biomicroscopy. Mean IOP decreased significantly from 22.15±9.5 mm Hg preoperatively to 13.3±9.9 mm Hg at last follow-up (at 245±120.0 d). The number of medications was reduced significantly from 3.15±1.2 preoperatively to 0.55±0.94 postoperatively. Complete success rate was 65% for both success criteria. CONCLUSIONS: Filtering blebs occur rarely after canaloplasty. In canaloplasty, IOP reduction seems to be independent of subconjunctival aqueous drainage, thus, avoiding the problems of conjunctival scarring.

Diurnal and nocturnal intraocular pressure fluctuations after trabeculectomy.

PURPOSE: The aim of this study was to compare diurnal and nocturnal intraocular pressure (IOP) fluctuations before and after trabeculectomy, and to evaluate the potential of trabeculectomy to even out IOP peaks. MATERIALS AND METHODS: Retrospectively, 35 diurnal and nocturnal IOP curves of patients (35 eyes) who underwent trabeculectomy were analyzed. Diurnal and nocturnal IOP profiles were recorded from 06:00 to 23:59 and 00:00 to 06:00, respectively. Follow-up was at least 300 days. Two criteria for success were defined: (1) IOP ≤21 mm Hg and at least a 20% IOP reduction from baseline; (2) <18 mm Hg without medication. RESULTS: The preoperative maximum diurnal and nocturnal IOP (IOP(max)) were 26.5 ± 5.9 and 23.4 ± 5.2 mm Hg, respectively. The postoperative diurnal and nocturnal IOP(max) were 16 ± 4.4 and 16 ± 5.4 mm Hg, respectively. Pre- to postoperative IOP reductions were statistically different (day 40% and night 32%; p < 0.001). Diurnal fluctuation was reduced significantly from 12.1 ± 4.2 mm Hg preoperatively to 5.6 ± 2.2 mm Hg postoperatively (reduction of 54%), and nocturnal fluctuation from 7.1 ± 4.5 to 3.9 ± 4.1 mm Hg (reduction of 46%, statistically insignificant due to large SD), respectively. Success criteria 1 and 2 were achieved in 71 and 54% of patients at daytime and in 63 and 57% at nighttime (no statistically significant difference detectable). Follow-up was 2.1 ± 1.7 years. CONCLUSIONS: Trabeculectomy achieves a leveling of IOP(max) in the diurnal-nocturnal comparison. The preoperative fluctuations could be nearly bisected. Relating to the success criteria, the statistical analysis did not reveal a difference in the diurnal-nocturnal comparison.

The prognostic value of the wuerzburg bleb classification score for the outcome of trabeculectomy.

BACKGROUND: the Wuerzburg bleb classification score (WBCS) aims at an objective and standardized assessment of the developing filtering bleb after trabeculectomy, in order to detect and treat bleb scarring at the earliest possible stage of development. The purpose of this retrospective study was to evaluate the prognostic value of the early postoperative WBCS for the long-term outcome of trabeculectomy. METHODS: the WBCS is a grading system for clinical bleb morphology. It evaluates the following parameters: vascularization, corkscrew vessels, encapsulation and microcysts. The WBCS of 113 eyes of 113 consecutive patients after trabeculectomy was determined 1 day, 1 and 2 weeks, 3, 6 and 12 months after surgery. Complete success was defined as an intra-ocular pressure (IOP) <21 mm Hg and >20% pressure reduction without glaucoma medication after 1 year. RESULTS: a complete success rate of 73.9% and a qualified success rate of 82.4% were achieved 1 year after surgery. The average total bleb score during follow-up in the success group was always higher than in the failure group, but there was no statistically significant difference at any time. The bleb average score for eyes with an IOP of ≤ 12 mm Hg after 2 weeks was significantly higher (p = 0.005) than for eyes with an IOP ≥ 13 mm Hg at the end of follow-up. CONCLUSION: patients with a higher early WBCS postoperatively had a significantly lower IOP 1 year after surgery. However, the study could not reveal a certain prognostic value of the early total bleb score using the WBCS for the long-term complete success of trabeculectomy.

Influence of conjunctival suture removal on the outcome of trabeculectomy.

BACKGROUND: To evaluate the influence of early conjunctival suture removal following trabeculectomy on postoperative outcome. METHODS: In a prospective randomized clinical trial 73 eyes of 69 consecutive patients eligible for primary trabeculectomy were included in the study. Eyes were randomly assigned to a control or intervention group. Trabeculectomy was performed with a fornix-based conjunctival flap and a conjunctival running mattress-suture. In the intervention group, the conjunctival suture was removed 4 weeks postoperatively, in the control group the suture remained in place. Both groups were followed for up to 12 months and best corrected visual acuity (BCVA), refraction, corneal topography, intraocular pressure (IOP), anterior segment and fundus were assessed preoperatively and within a week, 1, 3, 6 and 12 months after surgery. Statistical analysis was performed using SPSS for Windows (t test for independent samples). RESULTS: Trabeculectomy induced similar astigmatism in both groups. Compared to the control group, suture removal seemed to improve BCVA at 6 and 12 months. This was associated with a significantly lower IOP at 6 and 12 months and a significantly higher complete success rate at 12 months (94 vs. 65%, p < 0.001). Astigmatism was not significantly altered by suture removal. CONCLUSION: Conjunctival suture material appears to hamper trabeculectomy success and postoperative visual acuity. This is independent of postoperative astigmatism. Early removal of conjunctival sutures is advisable.

Interobserver variability of the Würzburg bleb classification score.

BACKGROUND: The Würzburg bleb classification score (WBCS) serves to assess filtering blebs in a standardized fashion. The purpose of this prospective masked agreement study was to evaluate the WBCS interobserver variability. METHODS: The WBCS provides a scheme to grade clinical bleb morphology. It evaluates the following parameters: vascularity, corkscrew vessels, encapsulation, microcysts and bleb height. Thus, 113 eyes of 104 consecutive patients at various times after surgery were examined (slit lamp biomicroscopy) by 3 ophthalmologists with each observer being unaware of the findings reported by the others. To calculate the interobserver variability of the WBCS, the interobserver consistency and absolute agreement were determined with an intraclass correlation coefficient (ICC) using a 2-way random model. RESULTS: The ICC values of a single rater's judgment were: vascularity +0.62, corkscrew vessels +0.67, encapsulation +0.63, bleb height +0.53, microcysts +0.52 and total score +0.74. The ICC values of the mean of all 3 raters were: +0.83 vascularity, +0.86 corkscrew vessels, +0.84 encapsulation, +0.77 bleb height, +0.76 microcysts and +0.90 total score. CONCLUSION: The WBCS is a bleb morphology score with high levels of interobserver consistency and absolute agreement in clinical practice.

CO2, excimer and erbium:YAG laser in deep sclerectomy.

PURPOSE: Deep sclerectomy is a non-penetrating filtering procedure that is not generally accepted, as tissue dissection is difficult and varying success rates have been reported. The purpose of the present study was to compare the use of CO2, excimer and erbium:YAG lasers in dissection of the deep corneoscleral lamella. METHODS: In enucleated porcine eyes a superficial lamellar scleral flap of 5 x 5 mm was surgically dissected. The deep lamella was removed using a pulsed erbium:YAG, a CO2 or an excimer laser (10 eyes/group). All eyes were analysed histologically and 3 in each group by scanning electron microscopy (SEM). RESULTS: It is feasible to ablate the deep corneoscleral lamella with the CO2, excimer and erbium:YAG lasers without perforating the anterior chamber. The following histology and SEM showed a smoother surface after dissection with the CO2 and excimer lasers compared to the erbium:YAG laser. There was no thermal damage after excimer laser treatment, compared to a damage zone of 10-30 mum using the erbium laser and one of 70-100 microm with the CO2 laser. CONCLUSIONS: Excimer,erbium:YAG and CO2 lasers allow the microsurgical dissection of the deep lamella. The excimer and CO2 lasers achieve a more regular and smoother tissue surface. The excimer laser has the advantage to dissect without thermal tissue damage.

Long-term results of surgery in childhood glaucoma.

PURPOSE: The aim of this study is to assess the functional results and morphological parameters in children surgically treated for glaucoma. METHODS: Data from 43 patients and 68 eyes who were operated in our department between 1990 and 2002 were collected. This retrospective trial included primary congenital glaucoma (n=36), and secondary glaucoma (n=7) in Rieger-Axenfeld syndrome and Sturge Weber syndrome. Intraocular pressure (IOP), axial length of the eyeball, visual acuity, refractive errors and orthoptic status were analysed. RESULTS: The age of patients at the first surgery was 6.0 +/- 5.3 months (range 0.7 to 28.0 months). The mean period of follow-up was 57.3 +/- 36.8 months (6.0-161.0). The mean number of surgical procedures performed on one eye was 2.5 +/- 2.4 procedures (1-11). The mean IOP before the first surgery was 31.0 +/- 7.9 mmHg (17.5-52.0), and was 15.0 +/- 3.9 mmHg (7.0-28.0) at the last visit. 49 eyes (72.1%) did not need any further medical treatment after the last surgical procedure. The IOP was 18 mmHg or lower without medication in 29 eyes (42.6%) after just one surgical procedure (21 trabeculotomy, 8 combined trabeculotomy/trabeculectomy with or without mitomycin-C). At the first examination, the mean axial length of the eyeball was 22.6 +/- 1.8 mm (the mean normal value at this age is 20.3 +/- 0.7 mm), and was 24.4 +/- 2.0 mm at the last visit (the mean normal value at this age is 22.2 +/- 0.6 mm). The best corrected visual acuity at the last visit was 0.25 +/- 4.6 lines; the normal range of visual acuity at this age is from 0.4 +/- 4.0 lines to 0.8 +/- 3.0 lines. Visual acuity was 0.32 or more in 53.0% of the eyes. Visual acuity was lower than 0.1 in only 15.2% of the eyes. Myopia was present in 57.4% of the eyes with a mean spherical equivalent of -6.1 +/-3.9 dioptres. 15 patients (34.9%) developed strabismus. 22 patients (51.2%) were treated with part-time occlusion. Binocular function as assessed with the Lang-1 test was positive in 17 of 30 patients (56.7%). CONCLUSIONS: Although a good long-term IOP-control can often be achieved in childhood glaucoma, the visual acuity remains below the normal range in most cases despite close orthoptic follow-up.