Comparative in vitro flow study of 3 different Ex-PRESS miniature glaucoma device models.

PURPOSE: To determine the flow characteristics of the 3 different models of the Ex-PRESS miniature glaucoma device in a controlled laboratory study. MATERIALS AND METHODS: The 3 different Ex-PRESS models (P-50, R-50, and P-200; Optonol Ltd; now Alcon Lab) were tested using a gravity-driven flow test. Three samples of each of the 3 Ex-PRESS models were subjected to a constant gravitational force of fluid at 5 different pressure levels (5 to 25 mm Hg). Four measurements per sample were taken at each pressure level. The main outcome measure was flow rate (Q) (µL/min). Resistance (R) was calculated by dividing pressure (P) by the measured flow (Q). RESULTS: The flow rate was primarily pressure dependent. The P-200 model (internal diameter 200 µm) showed a statistically significant higher flow rate and lower resistance compared with both the P-50 and R-50 models (internal diameter 50 µm) (P<0.0001). The P-50 and R-50 models demonstrated similar flow rates (P=0.08) despite their difference in tube length (2.64 vs. 2.94 mm). CONCLUSIONS: The 3 models of the Ex-PRESS mini shunt behaved in vitro as simple flow resistors by creating a relatively constant resistance to flow. Tube diameter was the only parameter with significant impact on flow and resistance. All models demonstrated flow rates per unit of pressure much higher than the outflow facility of a healthy human eye.

Optic disc area and diameter of the central retinal vein occlusion fellow eyes, determined by optical coherence tomography.

OBJECTIVE: To investigate the diameters and disc area of central retinal vein occlusion fellow eyes (CRVO fellow eyes), whether there is any small diameter of the particular axis, which predisposing to central retinal vein occlusion (CRVO), or not. MATERIAL AND METHOD: A prospective analytic study between 78 CRVO fellow eye patients and 102 healthy control subjects was evaluated. Fast optic disc scan with Stratus OCT was obtained. RESULTS: Six axes of disc diameters, and disc area were not different between the groups. Analysis of the model excluding glaucoma within the study group (n = 59) revealed the similar outcome. CONCLUSION: Optic disc diameters and size in the CRVO fellow eyes were not different from normal subjects. Optic disc size appears not to be the pathogenesis of CRVO.

24-Hour intraocular pressure control between travoprost/timolol fixed combination, latanoprost/ timolol fixed combination and standard timolol in primary open angle glaucoma and ocular hypertension.

OBJECTIVES: To evaluate the efficacy between Travoprost 0.004%/Timolol 0.5% fixed combination, Latanoprost 0.005%/ Timolol 0.5% fixed combination once a day in the morning and Timolol 0.5% twice a day in a 24-hour intraocular pressure control (IOP). MATERIAL AND METHOD: The patients with primary open angle glaucoma and ocular hypertension was subjected. After 2-4 weeks of washout period, patients with daytime IOP > or = 21 mmHg and < 36 mmHg were admitted to the hospital for 24-hour IOP monitoring every 3-hour interval starting from 9 am to 9 am the next day. The patients were randomly received Travoprost-Timolol fixed combination, Latanoprost-Timolol fixed combination once a day or Timolol twice a day in the studied eyes. Another 24-hour IOP monitoring was taken again 2 weeks later. RESULTS: 59 eyes from 32 patients were subjected. The mean initial IOP at 9 am was 21.6 mmHg. The mean reduction of IOP ranging from 1.6 to 7.3 mmHg for Travoprost-Timolol group, 1.5 to 8.2 mmHg for Latanoprost-Timolol group and 2.2 to 5.6 mmHg for Timolol group. All three groups produced statistically significant reduction (p < 0.05) in mean IOP at all test times except; at 3 am for the Travoprost-Timolol group; at 3 am, 12 midnight-and 6 pm in the Latanoprost-Timolol group; and at 3 am and 9 pm in the Timolol group. The effects of IOP reduction of the combination drugs were greatest between 9 am and 3 pm with the morning dose of both combinations. There was no statistically significant difference in mean IOP reduction at any test time between the 2 combination drug groups but they were both better than Timolol alone at 9 am and 3 pm. CONCLUSION: A fixed combination of Travoprost 0.004% and Timolol 0.5% is as effective as a fixed combination of Latanoprost 0.005% and Timolol 0.5% and are better than Timolol 0.5% in 24-hour IOP control.

Ultrasound biomicroscopy measured anterior and posterior chamber diameters--a novel way to evaluate angle-closure glaucoma.

OBJECTIVE: To investigate anterior and posterior chamber diameters in primary angle-closure (PAC) and to correlate them to the angle opening parameters. MATERIAL AND METHOD: Fifty eyes of PAC and 45 age-matched controls underwent ultrasound biomicroscopy (UBM; model P60, Paradigm Medical Industries Inc., Salt Lake City, UT) scanning. Superior, inferior temporal and nasal angle opening parameters were obtained. Anterior chamber diameter, indicated by angle-to-angle diameter (AAD) and posterior chamber diameter indicated by sulcus-to-sulcus diameter (SSD), were analyzed. RESULTS: Mean age was not different between PAC and controls, 59.80 +/- 9.11 versus 56.33 +/- 13.39, respectively (p = 0.140). PAC demonstrated a relatively smaller eye than the controls; e.g., corneal diameter; anterior chamber depth (ACD) and axial length, (all p < 0.05). AAD was shorter in PAC than the controls, 10.16 +/- 0.58 versus 10.88 +/- 0.55 mm, (p < 0.001). AAD was correlated to PAS extent (r = -0.358), ACD (r = 0.659), SSD (r = 0.636) and scleral spur to iris root insertion (r = 0.505), (all p < 0.001). SSD was also smaller in PAC than controls, 10.16 +/- 0.45 versus 10.52 +/- 0.52 mm, (p = 0.001). CONCLUSION: Crowded anterior segment of PAC can be demonstrated by a novel parameter of AAD and SSD, obtained with a newer model of UBM. The shorter AAD indicates the greater PAS extent and smaller angle. Both parameters are independent to scleral spur, and are simple to evaluate PAC.

Interobserver agreement in the interpretation of single-field digital fundus images for diabetic retinopathy screening.

PURPOSE: To assess agreement among a group of ophthalmic care providers, including ophthalmologists and trained nonphysician personnel, in the interpretation of single-field digital fundus images for diabetic retinopathy screening. DESIGN: Interobserver reliability study. PARTICIPANTS: Twelve ophthalmic care personnel, including 3 retina specialists, 3 general ophthalmologists, 3 ophthalmic nurses, and 3 ophthalmic photographers. METHODS: All participants were to read 400 good single-field digital fundus images of diabetic patients from a community hospital. The nonphysician personnel group read the images 1 month after attending a 2-day intensive instruction course regarding diabetic retinopathy screening. The ophthalmologists read the images without additional training. The 3 retina specialists read the images again together 2 months later to form a consensus regarding retinopathy severity and macular edema for each case. All readers used the Early Treatment Diabetic Retinopathy Study standard photographs as guidelines. MAIN OUTCOME MEASURES: The kappa statistic was used for the reliability assessment of the diabetic retinopathy severity and macular edema, and for the identification of cases that needed referral to ophthalmologists. RESULTS: There is only fair agreement among all readers. The multirater kappa coefficient for retinopathy severity is 0.34; for macular edema, 0.27; and for referral cases, 0.28. Retina specialists have the best agreement among all groups (kappa = 0.58 for retinopathy severity or macular edema, kappa = 0.63 for referrals). There is also fair agreement when all readers are compared with the consensus of retina specialists (kappas = 0.35, 0.28, and 0.29 for retinopathy severity, macular edema, and referrals, respectively), and the retina specialist group also has the best agreement (kappas = 0.63, 0.65, and 0.67 for retinopathy severity, macular edema, and referrals). CONCLUSIONS: Without additional training, retina specialists may be the most reliable personnel to interpret single-field digital fundus images for diabetic retinopathy screening. For other ophthalmic care personnel to achieve comparable reliability, a comprehensive instruction course with specific continuing education is essential. Authorized nonphysician interpreters should be experts, and new standard photographs for single-field digital fundus image interpretation may also be required to improve interobserver reliability.