Effects of Trabecular Meshwork Width and Schlemm’s Canal Area on Intraocular Pressure Reduction in Glaucoma Patients

Purpose@#To evaluate the effects of baseline trabecular meshwork (TM) and Schlemm’s canal (SC) microstructures on intraocular pressure (IOP) reduction amount in treatment-naïve patients with primary open-angle glaucoma (POAG). @*Methods@#A total 69 eyes of POAG patients who had not been treated with IOP-lowering agent were enrolled in this retrospective study. The patients had been prescribed topical IOP-lowering agent and used it for 1 year. The morphologic features of the TM and SC were collected using anterior segment module of spectral-domain optical coherence tomography with enhanced depth imaging at baseline. Images of the nasal and temporal corneoscleral limbus were obtained with serial horizontal enhanced depth imaging B-scans and TM width and SC area were measured in each scan. We investigated the effects of baseline TM and SC microstructures on IOP reduction amount. @*Results@#The baseline IOP of 69 glaucomatous eyes was 17.9 ± 3.8 mmHg, and the mean amount of IOP reduction was 3.5 ± 2.1 mmHg after 1 year. Mean TM widths of nasal and temporal sector were 470.33 ± 80.05 and 479.74 ± 79.59 μm, respectively. SC area was measured as 4,818.50 ± 1,464.28, 4,604.23 ± 1,567.73 μm2 at nasal sector and temporal sector, respectively. The correlation analysis revealed a positive correlation between SC area and average amount of IOP reduction, indicating that the larger baseline SC area, the greater the IOP drop with topical IOP-lowering agents. However, no correlation was found between TM width and IOP lowering amount in patients with POAG. @*Conclusions@#The baseline SC area showed positive correlation with the IOP reduction amount in patients with POAG. This finding suggests that the SC area can be a clinical parameter to predict the IOP reduction amount before using IOP-lowering agents in POAG patient.

Effects of Trabecular Meshwork Width and Schlemm’s Canal Area on Intraocular Pressure Reduction in Glaucoma Patients

Purpose@#To evaluate the effects of baseline trabecular meshwork (TM) and Schlemm’s canal (SC) microstructures on intraocular pressure (IOP) reduction amount in treatment-naïve patients with primary open-angle glaucoma (POAG). @*Methods@#A total 69 eyes of POAG patients who had not been treated with IOP-lowering agent were enrolled in this retrospective study. The patients had been prescribed topical IOP-lowering agent and used it for 1 year. The morphologic features of the TM and SC were collected using anterior segment module of spectral-domain optical coherence tomography with enhanced depth imaging at baseline. Images of the nasal and temporal corneoscleral limbus were obtained with serial horizontal enhanced depth imaging B-scans and TM width and SC area were measured in each scan. We investigated the effects of baseline TM and SC microstructures on IOP reduction amount. @*Results@#The baseline IOP of 69 glaucomatous eyes was 17.9 ± 3.8 mmHg, and the mean amount of IOP reduction was 3.5 ± 2.1 mmHg after 1 year. Mean TM widths of nasal and temporal sector were 470.33 ± 80.05 and 479.74 ± 79.59 μm, respectively. SC area was measured as 4,818.50 ± 1,464.28, 4,604.23 ± 1,567.73 μm2 at nasal sector and temporal sector, respectively. The correlation analysis revealed a positive correlation between SC area and average amount of IOP reduction, indicating that the larger baseline SC area, the greater the IOP drop with topical IOP-lowering agents. However, no correlation was found between TM width and IOP lowering amount in patients with POAG. @*Conclusions@#The baseline SC area showed positive correlation with the IOP reduction amount in patients with POAG. This finding suggests that the SC area can be a clinical parameter to predict the IOP reduction amount before using IOP-lowering agents in POAG patient.

Effect of Head Position and Tube Entry on Corneal Endothelial Cells in Patients with Glaucoma Drainage Implants: A Cross-sectional Study

Purpose@#To investigate the effect of head tilt on the tube position of the Ahmed glaucoma valve (AGV) implanted in patients with glaucoma and to assess how the head tilt-induced alterations of tube parameters and the level of tube entry influence corneal endothelial cell density (ECD). @*Methods@#A total of 29 eyes of 26 patients with AGV implantation were included. Tube-cornea distance, tube-cornea angle, and intracameral tube length were measured using anterior segment optical coherence tomography in three different head positions (neutral, 30° temporalward tilt, and 30° nasalward tilt). The tube entry was assessed using static gonioscopy. ECD was measured using specular microscopy before and after surgery. @*Results@#The mean tube-cornea distance, tube-cornea angle, and intracameral tube length (neutral: 0.87 ± 0.39 mm, 30.56 ± 5.89˚, and 3.10 ± 0.82 mm, respectively) decreased with head tilts (temporalward: 0.82 ± 0.39 mm, 29.27 ± 5.82˚, and 3.04 ± 0.82 mm, respectively; nasalward: 0.83 ± 0.40 mm, 29.61 ± 6.04˚, and 3.05 ± 0.81 mm, respectively; all p < 0.01). The multivariate analyses found age and the tube insertion level to be associated with postoperative changes in the central ECD (p = 0.039 and 0.013, respectively), and the postoperative follow-up period and tube insertion level to be associated with the difference between the inferonasal and superotemporal ECDs (p = 0.034 and 0.007, respectively). @*Conclusions@#Mild alterations of head positions induced changes in the intracameral tube positions of AGV implants; nevertheless, it did not significantly affect ECD loss. However, the eyes with tubes inserted anteriorly to Schwalbe’s line may be more susceptible to corneal ECD loss.

Effect of Head Position and Tube Entry on Corneal Endothelial Cells in Patients with Glaucoma Drainage Implants: A Cross-sectional Study

Purpose@#To investigate the effect of head tilt on the tube position of the Ahmed glaucoma valve (AGV) implanted in patients with glaucoma and to assess how the head tilt-induced alterations of tube parameters and the level of tube entry influence corneal endothelial cell density (ECD). @*Methods@#A total of 29 eyes of 26 patients with AGV implantation were included. Tube-cornea distance, tube-cornea angle, and intracameral tube length were measured using anterior segment optical coherence tomography in three different head positions (neutral, 30° temporalward tilt, and 30° nasalward tilt). The tube entry was assessed using static gonioscopy. ECD was measured using specular microscopy before and after surgery. @*Results@#The mean tube-cornea distance, tube-cornea angle, and intracameral tube length (neutral: 0.87 ± 0.39 mm, 30.56 ± 5.89˚, and 3.10 ± 0.82 mm, respectively) decreased with head tilts (temporalward: 0.82 ± 0.39 mm, 29.27 ± 5.82˚, and 3.04 ± 0.82 mm, respectively; nasalward: 0.83 ± 0.40 mm, 29.61 ± 6.04˚, and 3.05 ± 0.81 mm, respectively; all p < 0.01). The multivariate analyses found age and the tube insertion level to be associated with postoperative changes in the central ECD (p = 0.039 and 0.013, respectively), and the postoperative follow-up period and tube insertion level to be associated with the difference between the inferonasal and superotemporal ECDs (p = 0.034 and 0.007, respectively). @*Conclusions@#Mild alterations of head positions induced changes in the intracameral tube positions of AGV implants; nevertheless, it did not significantly affect ECD loss. However, the eyes with tubes inserted anteriorly to Schwalbe’s line may be more susceptible to corneal ECD loss.

Adherence to Preservative-Free Dorzolamide/Timolol Fixed Combination Assessed by Counting the Unused Single-Dose Units

PURPOSE: To investigate the actual adherence to treatment with preservative-free dorzolamide-timolol fixed combination (DTFC) eyedrops of primary open-angle glaucoma (POAG) patients by counting the number of unused single-dose units of DTFC. METHODS: This study included 34 POAG patients newly prescribed with preservative-free DTFC eyedrops (formulated in single-dose units). The enrolled patients were asked to bring the unused DTFC units on their next visit after 2 weeks of treatment with DTFC. On their second visit, they were asked to complete a questionnaire regarding the self-reported adherence and the number of unused DTFC single-dose units was counted. The actual adherence (%) was calculated by dividing the expected number of used DTFC units by the actual number of used DTFC units. The correlation between the self-reported adherence and the measured adherence was assessed. RESULTS: Twenty-nine (93.5%) patients answered they adhered to the medication by more than 90% and 2 (6.5%) answered they instilled the eyedrops at 80-90% of the dosing schedule. However, after counting the unused DTFC single-dose units, 9 (29.0%) patients showed an actual adherence of <90%. Moreover, the actual adherence of 3 (9.7%) patients was <60%. Unexpectedly, 4 (12.9%) patients showed the actual adherence exceeding 100% (196%, 1 patient; 107-132%, 3 patients). CONCLUSIONS: We demonstrated a large difference between the self-reported and the actual adherence to treatment by counting the unused single-dose units of eyedrops. Preservative-free topical anti-glaucoma medications (formulated in single-dose units) provide clinicians an opportunity to assess the actual adherence of glaucoma patients by counting the unused units of eyedrops.

Characteristics of the Gray Optic Disc Crescent and Associated Factors

PURPOSE: To investigate the characteristics of the gray optic disc crescent and associated factors. METHODS: We retrospectively reviewed stereo fundus photographs of 590 glaucoma patients and 273 non-glaucoma patients. An experienced investigator evaluated the presence or absence of the gray crescent (a crescent-shaped, slate-gray pigmentation on the periphery of the neuroretinal rim) which is entirely inside the scleral crescent. Correlations with age, gender, refractive error, disc diameters, and the presence of glaucoma or peripapillary atrophy were also analyzed. RESULTS: Out of 863 patients, the gray crescent was observed in 166 patients and was found in 19.0% of glaucoma patients and 19.8% of non-glaucoma patients. The gray crescent was most often located temporally (30.1%) and most frequently occurred within only 1 quadrant (63.9%). The prevalence of the gray crescent was not correlated with refractive error (p = 0.61) or the occurrence of glaucomatous optic neuropathy (p = 0.25), but was significantly related to peripapillary atrophy (p < 0.001) and the horizontal diameter of the optic disc (p = 0.001). CONCLUSIONS: The gray optic disc crescent is a common finding within a glaucomatous or non-glaucomatous eye and factors significantly related to occurrence of the gray crescent include peripapillary atrophy and the horizontal diameter of the optic disc. Patients with gray crescent require special attention when the optic disc is examined.

Age and Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography

PURPOSE: To evaluate the association between age and peripapillary retinal nerve fiber layer (RNFL) thickness measured by Cirrus high-definition (HD) spectral domain optical coherence tomography (OCT) in healthy Korean subjects. METHODS: A total of 302 eyes from 155 healthy Korean subjects (age range, 20 to 79 years) underwent RNFL thickness measurements using the Cirrus HD-OCT. Average, quadrant, and clock-hour RNFL thickness parameters were analyzed in terms of age using linear mixed effect models. RESULTS: Average RNFL demonstrated a slope of -2.1 microm per decade of age (p < 0.001). In quadrant analysis, superior (-3.4 microm/decade, p < 0.001) and inferior (-2.9 microm/decade, p < 0.001) quadrants showed steeper slopes, whereas temporal (-1.1 microm/decade, p < 0.001) and nasal (-1.0 microm/decade, p < 0.001) quadrants revealed shallower slopes. Among the 12 clock-hour sectors, clock hours 6 (-4.5 microm/decade, p < 0.001) and 1 (-4.1 microm/decade, p < 0.001) showed the greatest tendency to decline with age; RNFLs of the 3 (-0.2 microm/decade, p = 0.391) and 4 (-0.6 microm/decade, p = 0.052) o'clock hour sectors did not show significant decay. CONCLUSIONS: RNFL thickness was associated with age, especially in superior and inferior areas. The topographic distribution of correlation between age and RNFL thickness was not uniform.

The Efficacy of a Monocular Drug Trial in Normal-Tension Glaucoma

PURPOSE: To evaluate the efficacy of a monocular drug trial in eyes with normal-tension glaucoma (NTG). METHODS: This prospective study enrolled 74 patients with NTG. The monocular drug trial was started using latanoprost 0.005% for one week. If the intraocular pressure (IOP) reduction was greater than 15%, the same medication was administered to both eyes for one month. The unadjusted change and adjusted change (the change in the treated eye minus the change in the contralateral eye) in IOP were evaluated, and the predictors of IOP response were analyzed by multivariate linear regression. RESULTS: Among the initial 74 patients, 31 (41.9%) were included; others were excluded because they did not meet the requisite conditions. The most significant predictors of IOP response in the initial eye and subsequent eye were the baseline IOPs in both eyes (beta = 0.907, 0.771, respectively). The adjusted change in IOP of the initial eye had greater association (beta = 0.589) with the IOP after monocular trial in the initial eye than that of unadjusted IOP change (beta = 0.279). The adjusted change in IOP also had greater predictability (beta = 0.348) for IOP after monocular trial in the subsequent eye than that of the unadjusted IOP change (beta = 0.090). CONCLUSIONS: Although the monocular trial in NTG patients had limited efficacy due to its stringent conditions, it was useful for evaluating the IOP response in the initial eye and for predicting the IOP response in the subsequent eye.

Clinical Validation of Visual Field Index in Glaucoma Patients with Central Visual Field Defects

PURPOSE: To evaluate the glaucoma discrimination ability of visual field index (VFI), a new perimetric index of Humphrey field analyzer II, in glaucoma patients with central and peripheral visual field defects (VFD). METHODS: Humphrey visual field test and OCT were performed in 204 glaucomatous eyes and 70 healthy eyes. The associations of VFI with mean deviation (MD), pattern standard deviation (PSD), and average retinal nerve fiber layer thickness (RNFLT) were analyzed using Pearson's correlation. The diagnostic abilities of the parameters were analyzed using the areas under the receiver operating characteristic curves (AUROC). The AUROC were compared between MD-matched patients with central VFD (at least one point with p 0.05). The AUROC value of VFI was greater than those of the MD and average RNFLT but was not different from that of PSD (p = 0.332) in the central VFD group. However, there were no significant differences between AUROC value of VFI and those of other parameters in the peripheral VFD group (all, p > 0.05). CONCLUSIONS: The results from the present study suggest that VFI may be more useful than MD in diagnosing glaucoma, especially in patients with central VFD.

Comparison and Repeatability of Anterior Segment Parameters Obtained by Galilei and Slit-lamp Optical Coherence Tomography

PURPOSE: To evaluate the repeatability and comparability of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements obtained by Galilei dual Scheimpflug analyzer (Ziemer, Port, Switzerland) and slit-lamp optical coherence tomography (SL-OCT; Heidelberg Engineering, Dossenheim, Germany). METHODS: ACD and CCT were measured by Galilei and SL-OCT in 68 eyes of 68 healthy young subjects. Each measurement was performed 3 times by a single examiner, and the repeatability of 3 consecutive measurements was analyzed. ACD and CCT measurements were compared between the 2 devices. RESULTS: Both Galilei and SL-OCT showed high repeatability (ICCs > or = 0.994) for ACD and CCT measurements. The mean ACD and CCT measured by Galilei were greater than SL-OCT measurements by 0.11 +/- 0.09 mm and 14.01 +/- 7.38 microm, respectively. The 95% limit of agreement values for ACD and CCT measurements were 0.36 mm, 27.66 microm, respectively, and were highly correlated (correlation coefficients > or = 0.89, p < 0.001). CONCLUSIONS: Although the repeatability of each device was high, ACD and CCT obtained by Galilei and SL-OCT were significantly different. These differences should be considered when interpreting ACD and CCT measurements obtained by the 2 devices.

Relationship Between Central Corneal Thickness and Scleral Thickness in Korean Glaucomatous Patients

PURPOSE: To evaluate the correlation between central corneal thickness (CCT) and scleral thickness (ST) in glaucoma patients. METHODS: Seventy-eight eyes of 78 patients with no previous history of intraocular surgery and 23 control eyes were enrolled in the present study. For all eyes, CCT, ST, axial length, anterior chamber depth and refractive error were measured by a single examiner. The correlations among the measurements were analyzed. RESULTS: The mean patient age was 57.32 +/- 9.44 years, and the mean CCT was 532.80 +/- 43.75 microm. The mean CCT of ocular hypertension (576.00 +/- 26.59 microm) was thicker than that of the normal control group (530.30 +/- 35.34 microm, p = 0.028), although the mean STs of the groups were not significantly different. No significant correlation was found between CCT and ST (r = -0.073, p = 0.466). CONCLUSIONS: In the present study, no correlation between CCT and ST was observed. In addition, the STs of the groups were not significantly different.

Scanning Laser Polarimetry and Optical Coherence Tomography for Detection of Retinal Nerve Fiber Layer Defects

PURPOSE: To compare the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and Stratus optical coherence tomography (OCT) to detect photographic retinal nerve fiber layer (RNFL) defects. METHODS: This retrospective cross-sectional study included 45 eyes of 45 consecutive glaucoma patients with RNFL defects in red-free fundus photographs. The superior and inferior temporal quadrants in each eye were included for data analysis separately. The location and presence of RNFL defects seen in red-free fundus photographs were compared with those seen in GDx-VCC deviation maps and OCT RNFL analysis maps for each quadrant. RESULTS: Of the 90 quadrants (45 eyes), 31 (34%) had no apparent RNFL defects, 29 (32%) had focal RNFL defects, and 30 (33%) had diffuse RNFL defects in red-free fundus photographs. The highest agreement between GDx-VCC and red-free photography was 73% when we defined GDx-VCC RNFL defects as a cluster of three or more color-coded squares (p<5%) along the traveling line of the retinal nerve fiber in the GDx-VCC deviation map (kappa value, 0.388; 95% confidence interval (CI), 0.195 to 0.582). The highest agreement between OCT and red-free photography was 85% (kappa value, 0.666; 95% CI, 0.506 to 0.825) when a value of 5% outside the normal limit for the OCT analysis map was used as a cut-off value for OCT RNFL defects. CONCLUSIONS: According to the kappa values, the agreement between GDx-VCC deviation maps and red-free photography was poor, whereas the agreement between OCT analysis maps and red-free photography was good.

Comparison of the Central Retinal Vessel Diameter Between Glaucomatous and Normal Eye

PURPOSE:To compare the diameter of central retinal vessels between patients with normal-tension glaucoma, primary open-angle glaucoma and healthy (control) eyes. METHODS: The authors reviewed 30 eyes of 30 normal-tension glaucoma patients, 20 eyes of 20 primary open-angle glaucoma patients and 30 eyes of normal persons who had no systemic vascular diseases. The diameters of the central retinal arteries and veins were measured and calculated using a revised Parr-Hubbard formula, and results were compared between the groups. RESULTS: The diameter of the central retinal vessel showed no statistical differences between the eyes with normal-tension glaucoma and primary-open angle glaucoma. However, there were significant differences between the eyes of patients with glaucoma and the normal control eyes (p<0.05). Conclusion: The diameter of the central retinal vessels in glaucoma patients were narrower than that in the control group. Our results suggest that the diameter of the central retinal vessels may affect the development of glaucoma both in normal tension and primary open-angle types, or that glaucomatous damage may influence the diameter of the central retinal vessels.

Visual Outcome in Children With Congenital Glaucoma

PURPOSE:To evaluate the prognosis of vision and the development of amblyopia in primary congenital glaucoma patients. METHODS: The author reviewed 38 eyes of 22 primary congenital glaucoma patients and evaluated variables such as age at time of surgery and at the last visit, preoperative IOP, Cup-to-disc(CD) ratio, corneal diameter, refractive error, axial lengths and IOP, CD ratio and visual acuity at the last visit. According to visual acuity, the patients were divided into 3 groups, good (>0.5), fair (0.1~0.5), and poor (<0.1). The amblyopia was defined when BCVA was below 0.8 and no evidence of progression of glaucoma. There were 4 types of amblyopia: deprivation, anisometropic, strabismic and organic. The author compared the 3 groups and evaluated factors affecting the vision as well as the prevalence of amblyopia. RESULTS: There were 17 eyes in the good group, 4 eyes in the fair group and 17 eyes in the poor group (p<0.05). Amblyopia developed in 17 eyes with 7 eyes showing deprivation amblyopia. Anisometropic and organic amblyopia were each found in 4 eyes, and strabismic amblyopia was found in 2 eyes. The postoperative IOP and CD ratio and preoperative CD ratio were significantly lower in the good group than the other groups (p<0.05). CONCLUSIONS: Final VA was poor in 45% of eyes with primary congenital glaucoma, and amblyopia developed in 45% of these eyes. The prognosis for vision may be related to the treatment of glaucoma and amblyopia.

Trabeculectomy for Medically Uncontrolled Acute Primary Angle-Closure Glaucoma

PURPOSE: To evaluate the outcomes of trabeculectomy performed on eyes with medically uncontrolled acute angle closure glaucoma (AACG). METHODS: The authors reviewed 31 eyes of 30 acute primary angle-closure glaucoma patients who had undergone trabeculectomy. The eyes were divided into two groups: eyes which did not respond to medical and/or laser treatment (Group A, 16 eyes) and those which initially responded to medical and/or laser treatment and later had an intraocular pressure (IOP) increase (Group B, 15 eyes). Complete success was defined as a final IOP below 21 mmHg without medication, and qualified success was defined as a final IOP below 21 mmHg with medication. Patients whose postoperative IOP was 22 mmHg or greater on at least two serial measurements or who required additional glaucoma surgery were classified as failures. RESULTS: The mean follow-up was 43.1+/-32.3 months. The five-year qualified success rate was 56.3% in Group A and 100% in Group B (log-rank test, p=0.02). The preoperative IOP was significantly higher in Group A (38.0+/-11.5 mmHg) than in Group B (21.8+/-12.2 mmHg) (p0.05). CONCLUSIONS: The medically uncontrolled AACG appears to have an adverse effect on the outcome of trabeculectomy. Success of trabeculectomy in AACG seems to be inversely related with elevated preoperative intraocular pressure.

Trabeculectomy for Medically Uncontrolled Acute Primary Angle-Closure Glaucoma

PURPOSE: To evaluate the outcomes of trabeculectomy performed on eyes with medically uncontrolled acute angle closure glaucoma (AACG). METHODS: The authors reviewed 31 eyes of 30 acute primary angle-closure glaucoma patients who had undergone trabeculectomy. The eyes were divided into two groups: eyes which did not respond to medical and/or laser treatment (Group A, 16 eyes) and those which initially responded to medical and/or laser treatment and later had an intraocular pressure (IOP) increase (Group B, 15 eyes). Complete success was defined as a final IOP below 21 mmHg without medication, and qualified success was defined as a final IOP below 21 mmHg with medication. Patients whose postoperative IOP was 22 mmHg or greater on at least two serial measurements or who required additional glaucoma surgery were classified as failures. RESULTS: The mean follow-up was 43.1+/-32.3 months. The five-year qualified success rate was 56.3% in Group A and 100% in Group B (log-rank test, p=0.02). The preoperative IOP was significantly higher in Group A (38.0+/-11.5 mmHg) than in Group B (21.8+/-12.2 mmHg) (p0.05). CONCLUSIONS: The medically uncontrolled AACG appears to have an adverse effect on the outcome of trabeculectomy. Success of trabeculectomy in AACG seems to be inversely related with elevated preoperative intraocular pressure.

Changes in RNFL Thickness According to the Myopia in Patients with Glaucoma and Ocular Hypertension

PURPOSE: To evaluate the changes in retinal nerve fiber layer (RNFL) thickness according to the degree of myopia in patients with glaucoma and ocular hypertension. METHODS: Ninety-eight patients (165 eyes) diagnosed with glaucoma or ocular hypertension underwent optical coherence tomography (OCT) and scanning laser polarimetry using variable corneal compensation (GDx-VCC) to analyze the correlation between the degree of myopia and the thickness of the RNFL. A partial correlation coefficient analysis was performed to adjust for various factors such as age, laterality, intraocular pressure, and the mean deviation from visual field test, which can influence the RNFL thickness. RESULTS: The average, nasal, superior, and inferior sectorial RNFL thicknesses measured by OCT significantly decreased with increasing myopia (p<0.05). However, RNFL thickness measured by GDx-VCC was not significantly correlated with the degree of myopia. CONCLUSIONS: The RNFL thickness measured by OCT decreased with increasing myopia in eyes with glaucoma and ocular hypertension.

Pericardium Plug in the Repair of the Corneoscleral Fistula After Ahmed Glaucoma Valve Explantation

We report four cases in which a pericardium (Tutoplast(R)) plug was used to repair a corneoscleral fistula after Ahmed Glaucoma Valve (AGV) explantation. In four cases in which the AGV tube had been exposed, AGV explantation was performed using a pericardium (Tutoplast(R)) plug to seal the defect previously occupied by the tube. After debridement of the fistula, a piece of processed pericardium (Tutoplast(R)), measured 1 mm in width, was plugged into the fistula and secured with two interrupted 10-0 nylon sutures. To control intraocular pressure, a new AGV was implanted elsewhere in case 1, phaco-trabeculectomy was performed concurrently in case 2, cyclophotocoagulation was performed postoperatively in case 3 and anti-glaucomatous medication was added in case 4. No complication related to the fistula developed at the latest follow-up (range: 12~26 months). The pericardium (Tutoplast(R)) plug seems to be an effective method in the repair of corneoscleral fistulas resulting from explantation of glaucoma drainage implants.

The Effect of Flat Anterior Chamber on the Success of Ahmed Valve Implantation

PURPOSE: To evaluate the outcome following Ahmed valve implantation in patients who developed flat anterior chamber. METHODS: The authors reviewed 60 eyes of 60 patients who underwent Ahmed valve implantation and divided these patients into the flat anterior chamber group (18 eyes) and the control group (42 eyes). The influence of clinical variables on the development of flat anterior chamber and the effect of flat anterior chamber on the success of Ahmed valve implantation were evaluated. RESULTS: The preoperative intraocular pressure, age, and the incidence of neovascular glaucoma as a preoperative diagnosis were higher in the flat anterior chamber group than in the control group (p0.05). CONCLUSIONS: The development of a flat anterior chamber after Ahmed valve implantation appeared not to affect the outcome of the surgery.

Peripheral Anterior Synechiae and Ultrasound Biomicroscopic Parameters in Angle-Closure Glaucoma Suspects

PURPOSE: To investigate the correlation between peripheral anterior synechia (PAS) and the quantitative anterior chamber angle parameters measured by ultrasound microscopy (UBM) in angle-closure glaucoma suspect (ACGS) eyes. METHODS: Eyes were defined ACGS as having occludable angles and intraocular pressure less than 21 mm Hg without glaucomatous optic nerve head. The gonioscopic criteria for ACGS were the trabecular meshwork invisible in 3 or more quadrants of the entire angle and the angular width less than 20 degrees by Shaffer classification. Twenty-seven eyes of 20 patients underwent anterior chamber angle and ciliary body imaging with UBM. Angle opening distance (AOD500), angle recess area (ARA), trabecular-ciliary process distance (TCPD) and trabecular-iris angle (TIA) were measured from the UBM images at each quadrant. RESULTS: The AOD500, ARA, and TIA were not significantly different between the eyes with PAS (9 eyes) and without PAS (18 eyes) at each quadrant. However, the TCPD was significantly shorter in the superior quadrant when compared with the eyes without PAS (mean: 405.3+/-70.9 micrometer vs 536.4+/-140.5 micrometer) (p<0.05). CONCLUSIONS: The results suggest that the shorter distance from trabecular meshwork to ciliary body or the anterior placement of ciliary process may play a role in the development of PAS in ACGS eyes.