Canaloplasty in Corticosteroid-Induced Glaucoma. Preliminary Results.

PURPOSE: to present the mid-term results of canaloplasty in a small cohort of corticosteroid glaucoma patients. MATERIAL AND METHODS: Nine eyes from seven patients with various types of corticosteroid glaucoma in maximum medical therapy underwent canaloplasty. Patients underwent complete ophthalmic examination every six months. Success was defined as: post-operative intraocular pressure (IOP) ≤ 21 mmHg and ≤ 16 mmHg without ("complete success"), and with/without medical treatment ("qualified success"). The IOP reduction had to be ≥ 20. The number of medications before and after surgery was considered. The follow-up mean period was 32.7 ± 20.8 months (range 14-72 months). RESULTS: The pre-operative mean IOP was 30.7 ± 7.2 mmHg (range: 24-45). The mean IOP at 6 and 12-month follow-up was 13.1 ± 2.6 mmHg, and 13.7 ± 1.9 mmHg, respectively. Qualified and complete success at 6 and 12 months was 100% for both of the two definitions. The number of medications used preoperatively and at the 12-month follow-up was 4.3 ± 0.7, and 0.2 ± 1.0, respectively. No serious complication was observed. CONCLUSIONS: The mid-term results of canaloplasty in patients with corticosteroid-induced glaucoma appear to be very promising. Canaloplasty should be considered as a possible alternative to filtering surgery in this form of glaucoma, when medical therapy is not sufficient to maintain the IOP within reasonable limits.

Canaloplasty in Open-angle Glaucoma: Mid-term Results From a Multicenter Study.

PURPOSE: To present the mid-term results of a prospective multicenter study on canaloplasty surgery in chronic open-angle glaucoma. MATERIALS AND METHODS: A total of 218 eyes from 197 patients with open-angle glaucoma under maximum tolerated medical therapy underwent canaloplasty within a time period of 42 months in 3 different Italian eye centers. All patients underwent a complete ophthalmic examination every 6 months. The follow-up ranged from 3 to 42 months. RESULTS: The entire procedure according to standard protocol could not be performed in 20 eyes (9.2%). A total of 198 eyes from 178 patients with a mean follow-up of 23.1±10.6 months were taken into consideration. The preoperative mean intraocular pressure (IOP) was 28.4±7.5 mm Hg. The mean IOP at the 2-year follow-up was 15.9±4.7 mm Hg (range, 6 to 40 mm Hg; paired t test; P=0.0001), with a mean reduction from baseline of 44% (range, 11.1% to 82.8%). After 2 years of follow-up, a qualified success rate based on postoperative IOP≤21, ≤18, and ≤16 mm Hg was obtained in 82 (92.1%), 75 (84.3%), and 61 (68.5%) eyes, respectively; a complete success for an IOP≤21, ≤18, and ≤16 mm Hg was obtained in 63 (70.8%), 60 (67.4%), and 53 (59.5%) eyes, respectively. The number of medications used preoperatively and at the 2-year follow-up was 3.2±0.9 and 1.1±1.3, respectively. The most frequently seen complications included: hyphema in 47 eyes (23.7%), Descemet membrane detachment in 11 eyes (5.5%), and IOP spikes >10 mm Hg in 12 cases (6.1%). CONCLUSIONS: Canaloplasty is a quite difficult surgical technique; however, mid-term results are promising. Complications can sometimes occur, but are seldom serious. The main advantage of this promising bleb-less procedure is that physiological humor aqueous outflow is restored.

Corneal Deformation Parameters Provided by the Corvis-ST Pachy-Tonometer in Healthy Subjects and Glaucoma Patients.

PURPOSE: To evaluate precision and accuracy of Corvis-ST, a new noncontact tonometer equipped with a high-speed Scheimpflug technology, which measures intraocular pressure (IOP), central corneal thickness (CCT), and corneal deformation parameters (CDPs). Relationships among IOP, CCT, and CDPs were also assessed. MATERIALS AND METHODS: This prospective, randomized study included 1 eye of 164 subjects (79 controls and 85 glaucoma patients), which underwent IOP measurements taken 3 times with Goldmann applanation tonometry (GAT) and Corvis-ST in random order. Precision was evaluated using intraclass correlation coefficients. Intermethod agreement was assessed using Bland-Altman method. Relationships amongst IOP, CCT and CDPs were evaluated using linear regression analysis. RESULTS: Corvis-ST intraclass correlation coefficients ranged between 0.95 and 0.99 for IOP and CCT; between 0.17 and 0.97 for CDPs. Mean (GAT-Corvis-ST) IOP was 1.4±2.7 mm Hg, which appeared related to IOP and CDPs (P<0.05). CDPs significantly differed between glaucoma patients and controls (P<0.05). GAT and Corvis-ST IOP was related to CCT (P<0.05) and CDPs (P<0.001). CONCLUSIONS: Corvis-ST precision was excellent for IOP and CCT; moderate for CDPs. Corvis-ST underestimated GAT IOP, especially at higher IOP and at lower corneal deformability levels. GAT and Corvis-ST IOP increased in thicker and less deformable corneas. Glaucoma patients showed significantly less deformable corneas than controls.

Repeatability and accuracy of applanation resonance tonometry in healthy subjects and patients with glaucoma.

PURPOSE: To evaluate the repeatability and accuracy of the applanation resonance tonometer (ART) used in the automatic servo-controlled version, and to evaluate the influence of central corneal thickness (CCT) on the ART intraocular pressure (IOP) measurements. METHODS: This prospective, randomized, single-centre study included one eye of 153 subjects (35 healthy volunteers and 118 patients with glaucoma). All participants underwent ultrasonic CCT measurement, followed by IOP evaluation with Goldmann applanation tonometer (GAT) and ART in random order. A single operator measured the IOP with each tonometer three times. Intra-examiner variability was evaluated using the coefficient of variation (CoV), intraclass correlation coefficient (ICC) and test-retest differences. Intermethod agreement was assessed using the Bland-Altman method. Linear regression analysis was used to evaluate the relationship between IOP measurements and CCT. RESULTS: The mean IOP was 17.7 ± 4.4 mmHg with GAT and 20.6 ± 5.3 mmHg with ART (p < 0.001). CoV and ICC were, respectively, 5 ± 3% and 0.99 for GAT, and 8 ± 4% and 0.96 for ART (intermethods differences, p = 0.001). The ART test-retest differences significantly increased with increasing mean IOP (p = 0.003). The mean IOP difference (ART minus GAT) was 3.0 ± 4.0 mmHg, which increased with increasing mean IOP (p < 0.001). Both GAT IOP and ART IOP readings were significantly directly related to the CCT values (p = 0.03 and p = 0.004, respectively; intermethods difference, p = 0.32). CONCLUSIONS: The ART intra-examiner repeatability was excellent, although significantly lower than that of GAT, and decreased at higher IOP levels. ART significantly overestimated GAT IOP measurements, especially at higher IOP range. Both GAT and ART appeared similarly influenced by CCT value.

Canaloplasty after failed trabeculectomy: a possible option.

Canaloplasty is usually indicated for eyes that have not undergone previous filtrating surgery for glaucoma. In some cases, however, "trabeculectomy" can be targeted anterior to the angle components, thus leaving Schlemm's canal integral and untouched. In the past 4 years of performing canaloplasty in our Glaucoma Clinic in Udine, a total of 6 eyes with previous failed trabeculectomy and elevated intraocular pressure (IOP) despite maximum tolerated medical therapy underwent canaloplasty. The preoperative IOP was 32.2±9.6 mm Hg, ranging from 25 to 48 mm Hg. In this group of patients, canaloplasty could be correctly completed in 5 cases; in 1 case, however, Schlemm's canal could not be cannulated for the entire 360-degree circumference, thus surgery was converted into viscocanalostomy. Follow-up ranged between 6 and 28 months (mean, 16.7±9.3 mo). The mean IOP at 6, 12, 18, and 24 months was 17.3, 15.4, 14.7, and 16.3 mm Hg, respectively. The number of medications used before and at the 2-year follow-up was 3.2±1.2 and 2.3±0.5, respectively. Our results suggest that canaloplasty can be considered as a possible surgical option in eyes with failed trabeculectomy showing undamaged Schlemm's canal from previous filtrating surgery.

Optic disc damage staging system.

PURPOSE: To evaluate the optic disc damage staging system (ODDSS); a new clinical method of optic disc (OD) classification based on OD size, neural rim (NR) loss severity and localization. Accuracy, reproducibility, and reliability were studied. Agreement of ODDSS with the Heidelberg-Retina-Tomograph (HRT) results was evaluated. METHODS: One eye of 68 consecutive open-angle glaucoma (POAG) patients and 40 controls underwent standard automated perimetry (SAP), HRT-II, and OD examination using the ODDSS classification by 3 independent graders in this prospective cross-sectional study. Sensitivity, specificity, and area under the receiver operating characteristic curve (AROC) in discriminating between normal and POAG eyes were determined for ODDSS and HRT parameters. ODDSS intraobserver and interobserver agreement and agreement with HRT-Moorfield-Regression-Analysis (MRA) were assessed. RESULTS: ODDSS sensitivity ranged from 72.0% to 89.7%; specificity ranged from 92.5% to 100%. Differences between AROCs for ODDSS (0.89 to 0.94) and for the best-performing HRT parameter (Vertical Cup/Disc Ratio 0.88) were not statistically significant. ODDSS interobserver agreement ranged from 0.33 to 0.78; intraobserver agreement ranged from 0.53 to 0.89. Agreement with HRT-MRA ranged from 0.50 to 0.87. CONCLUSIONS: ODDSS is a new method for assessing, recording, and sharing information about the clinical OD appearance. Our preliminary results show that it provides good sensitivity and specificity in glaucoma detection. The interobserver and intraobserver agreement ranged from fair to good.

Comparisons between Pascal dynamic contour tonometry, the TonoPen, and Goldmann applanation tonometry in patients with glaucoma.

PURPOSE: To compare intraocular pressure (IOP) measurements taken with Pascal dynamic contour tonometry (DCT), the TonoPen and the Goldmann applanation tonometry (GAT). The influence of central corneal thickness (CCT) on IOP measurements taken with Pascal DCT and the TonoPen was evaluated. METHODS: One eye in each of 101 consecutive patients with primary open-angle glaucoma (POAG) underwent ultrasonic CCT measurement and IOP evaluation with GAT, Pascal DCT and the TonoPen in random order. The agreement between results from Pascal DCT and the TonoPen and those of GAT was assessed using the Bland-Altman method. The deviation of Pascal DCT and TonoPen readings from GAT values, corrected for CCT, was calculated and correlated to CCT using a linear regression model. RESULTS: The mean of the differences in IOP measurements was 3.2 +/- 2.4 mmHg for Pascal DCT minus GAT readings and 0.5 +/- 4.5 mmHg for TonoPen minus GAT readings. The 95% confidence interval of differences in IOP measurements was higher between TonoPen and GAT readings (- 6 to 7 mmHg) than between Pascal and GAT readings (0.1-6.8 mmHg). Pascal DCT significantly overestimated IOP compared with GAT, especially for higher IOP readings. Bland-Altman scatterplots showed reasonable inter-method agreement between Pascal DCT and GAT measurements, and poor agreement between TonoPen and GAT measurements. The deviations of Pascal DCT and TonoPen readings from the corrected GAT values were both highly correlated with CCT values (linear regression analysis, p < 0.0001). The mean change in measured IOP for a 10-microm increase in CCT was 0.48 mmHg for Pascal DCT and 0.74 mmHg for the TonoPen. CONCLUSIONS: Agreement with GAT measurements was higher for Pascal DCT than for TonoPen readings; however, Pascal DCT significantly overestimated IOP values compared with GAT. Measurements of IOP obtained with both Pascal DCT and the TonoPen appeared to be influenced by CCT, and this influence appeared to be greater for the latter.

Comparison between GDx VCC scanning laser polarimetry and Stratus OCT optical coherence tomography in the diagnosis of chronic glaucoma.

PURPOSE: To compare the abilities of scanning laser polarimetry with the variable corneal compensator (GDx VCC) with those of optical coherence tomography (Stratus OCT) in discriminating between healthy and early-to-moderate perimetric glaucomatous eyes. METHODS: A total of 95 glaucomatous patients (mean deviation - 3.7 +/- 3.0 dB, pattern standard deviation 4.5 +/- 2.7 dB) and 62 control subjects underwent imaging by the GDx VCC and Stratus OCT using both optic nerve head (ONH) and retinal nerve fibre layer (RNFL) scan protocols. One eye per patient was considered. Sensitivity at > or = 90% specificity and area under the receiver operating characteristic curve (AROC) were calculated for each GDx VCC and Stratus OCT index. RESULTS: The largest AROCs with Stratus OCT were associated with cup : disc area ratio (0.88) for ONH scan indices, and with average thickness (0.84) for RNFL scan indices. The nerve fibre indicator provided the greatest AROC for the GDx VCC indices (0.85). CONCLUSIONS: Both the GDx VCC and Stratus OCT instruments were shown to be useful in the detection of glaucomatous damage. The best performing indices for the GDx VCC and Stratus OCT with both ONH and RNFL scans gave similar AROCs, showing a moderate sensitivity in early-to-moderate glaucoma patients.

Comparison of ICare tonometer with Goldmann applanation tonometer in glaucoma patients.

PURPOSE: To compare the intraocular pressure (IOP) readings taken with the new ICare tonometer and with the Goldmann applanation tonometer (GAT) and to evaluate the influence of central corneal thickness (CCT) on the IOP measurements. PATIENTS AND METHODS: One eye of 178 consecutive patients with primary open-angle glaucoma underwent ultrasonic CCT measurement, followed by IOP evaluation with the GAT and with the ICare tonometer. The deviation of ICare readings from GAT values, corrected according to the Doughty and Zaman formula, was calculated and correlated to CCT by a linear regression model. The agreement between the 2 devices was assessed by use of the Bland-Altman method. RESULTS: The average CCT was 552+/-39 mum. The mean IOP and the mean corrected IOP with GAT were 19.4+/-5.4 mm Hg, and 18.5+/-5.7 mm Hg, respectively. The mean ICare IOP reading was 18.4+/-5.2 mm Hg. The deviations of ICare readings from corrected GAT values were highly correlated with CCT values (r=0.63, P<0.01). Linear regression analysis showed that a CCT change of 10 mum resulted in an ICare reading deviation of 0.7 mm Hg. The Bland-Altman scatter-plot showed a reasonable agreement between the 2 tonometers. CONCLUSIONS: The ICare tonometer can be useful in a routine clinical setting. The IOP readings are quite in accordance with those obtained by GAT. The measurements seemed to be influenced by CCT variations, and thus pachymetry should always be taken into consideration.

Visual field testing with the new Humphrey Matrix: a comparison between the FDT N-30 and Matrix N-30-F tests.

PURPOSE: To determine if the N-30-F test with the new Humphrey Matrix instrument is comparable to the traditional frequency-doubling technology (FDT) N-30 test. METHODS: A sample of 47 eyes from 47 patients (five normal subjects, 27 with ocular hypertension and 15 with glaucoma) underwent visual field (VF) testing with standard automated perimetry, and with FDT, using the FDT N-30 program, and the Matrix N-30-F program (using the same 19 tested points, full-threshold strategy, but with an enhanced algorithm to reduce testing time). The plots, mean deviation (MD), pattern standard deviation (PSD), defect locations and test time were compared. RESULTS: The agreement between the two tests was shown to be good, except for subjects with large VF defects, in which greater PSD values were observed with the FDT test, whereas the Matrix test gave a higher MD and number of abnormal test locations in the total deviation plot. A lack of agreement was also found for the number of abnormal test locations on the pattern deviation plot at any VF loss severity level. The test time for the Matrix test was significantly shorter. CONCLUSION: The FDT N-30 and Matrix N-30-F tests proved to be comparable in cases of early to moderate VF defects.

Staging of functional damage in glaucoma using frequency doubling technology.

PURPOSE: To evaluate three new approaches for staging severity of glaucomatous visual field defects using frequency doubling technology. PATIENTS AND METHODS: One hundred and four patients with either ocular hypertension or chronic glaucoma were tested with both standard automated perimetry (SAP, 30-2 Humphrey threshold test) and frequency doubling technology (N-30 threshold test). Standard automated perimetry results were classified into four groups (normal tests, early defects, moderate defects, and severe defects) using the Glaucoma Staging System. Frequency doubling technology tests were also classified in four groups using three different approaches: frequency doubling technology probability map analysis, considering the number and location of disturbed points, frequency doubling technology MD and PSD indices, graphed on a two-axis diagram (FDT Staging System), and an abnormality score, based on both the statistical significance and the spatial location of depressed points. A control group of 20 eyes from 20 normal subjects was also tested and classified in the same way. The Cohen Kappa was used to compare the level of agreement between the three frequency doubling technology methods of classification and the glaucoma staging system. RESULTS: Measure of agreement was 0.679 using probability map assessment, 0.793 using the frequency doubling technology staging system, and 0.663 using the abnormality score. The specificity rate was 95% for all three methods. CONCLUSIONS: All the studied approaches were able to correctly stage the glaucomatous functional damage, but the frequency doubling technology staging system was the easiest and quickest method. Moreover, it is the only method that supplies information on the characteristics of the defect, without requiring any other time-consuming procedures.