Gel Stent Versus Trabeculectomy: The Randomized, Multicenter, Gold-Standard Pathway Study (GPS) of Effectiveness and Safety at 12 Months.

PURPOSE: To compare effectiveness and safety of the gel stent to trabeculectomy in open-angle glaucoma (OAG). DESIGN: Prospective, randomized, multicenter, noninferiority study. METHODS: Patients with OAG and intraocular pressure (IOP) 15 to 44 mm Hg on topical IOP-lowering medication were randomized 2:1 to gel stent implantation or trabeculectomy. Primary end point (surgical success): percentage of patients at month 12 achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or secondary surgical intervention (SSI) in a noninferiority test with 24% margins. Secondary end points (month 12) included mean IOP and medication count, postoperative intervention rate, visual recovery, and patient-reported outcomes (PROs). Safety end points included adverse events (AEs). RESULTS: At month 12, the gel stent was statistically noninferior to trabeculectomy (between-treatment difference [Δ], -6.1%; 95% CI, -22.9%, 10.8%); 62.1% and 68.2% achieved the primary end point, respectively (P=.487); mean IOP and medication count reductions from baseline were significant (P<.001); and the IOP change-related Δ (2.8 mm Hg) favored trabeculectomy (P=.024). The gel stent resulted in fewer eyes requiring in-office postoperative interventions (P=.024 after excluding laser suture lysis), faster visual recovery (P≤.048), and greater 6-month improvements in visual function problems (ie, PROs; P≤.022). The most common AEs were reduced visual acuity at any time (gel stent, 38.9%; trabeculectomy, 54.5%) and hypotony (IOP <6 mm Hg at any time) (gel stent, 23.2%; trabeculectomy, 50.0%). CONCLUSIONS: At month 12, the gel stent was statistically noninferior to trabeculectomy, per the percentage of patients achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or SSI. Trabeculectomy achieved a statistically lower mean IOP, numerically lower failure rate, and numerically lower need for supplemental medications. The gel stent resulted in fewer postoperative interventions, better visual recovery, and fewer AEs.

Variance owing to observer, repeat imaging, and fundus camera type on cup-to-disc ratio estimates by stereo planimetry.

OBJECTIVE: To determine and compare variance components in linear cup-to-disc ratio (LCDR) estimates by computer-assisted planimetry by human experts, and automated machine algorithm (digital automated planimetry). DESIGN: Prospective case series for evaluation of planimetry. PARTICIPANTS: Forty-four eyes of 44 consecutive patients from the outpatient Glaucoma Service at University of Iowa with diagnosis of glaucoma or glaucoma suspect were studied. METHODS: Six stereo pairs of optic nerve photographs were taken per eye: 3 repeat stereo pairs using simultaneous fixed-stereo base fundus camera (Nidek 3Dx) and another 3 repeat stereo pairs using sequential variable-stereo base fundus camera (Zeiss). Each optic disc stereo pair was digitized and segmented into cup and rim by 3 glaucoma specialists (computer-assisted planimetry) and using a computer algorithm (digital automated planimetry), and LCDR was calculated for each segmentation (either specialist or algorithm). A linear mixed model was used to estimate mean, SD, and variance components of measurements. MAIN OUTCOME MEASURES: Average LCDR, interobserver, interrepeat, intercamera coefficients of variation (CV) of LCDR and their 95% tolerance limits. RESULTS: There was a significant difference in LCDR estimates among the 3 glaucoma specialists. The interobserver CV of 10.65% was larger than interrepeat (6.7%) or intercamera CV (7.6%). For the algorithm, the LCDR estimate was significantly higher for simultaneous stereo fundus images (Nidek, mean: 0.66) than for sequential stereo fundus images (Zeiss, mean: 0.64), whereas interrepeat CV for Nidek (4.4%) was lower than Zeiss (6.36%); the algorithm's interrepeat and intercamera CV were 5.47% and 7.26%, respectively. CONCLUSIONS: Interobserver variability was the largest source of variation for glaucoma specialists, whereas their interrepeat and intercamera variability is comparable with that of the algorithm. DAP reduces variability on LCDR estimates from simultaneous stereo images, such as the Nidek 3Dx.

Pathological optic-disc cupping.

PURPOSE OF REVIEW: Pathological optic-disc cupping is most often caused by glaucoma, but may be seen in many less-common neuro-ophthalmic conditions. The goal of this article is to examine a host of entities causing optic-disc cupping, present key differentiating characteristics and pathophysiologies, and outline diagnostic approaches. RECENT FINDINGS: Multiple entities not associated with elevated intraocular pressure or glaucomatous optic-nerve disease may result in pathologic optic-nerve excavation. Even with the photography and imaging of today, it is still difficult for the clinician to accurately diagnose other causes of optic-disc cupping. Up to 20% of patients may be misdiagnosed and treated for glaucoma due to misinterpretation of the optic-disc cupping. Newer forms of imaging including optical coherence tomography may assist the clinician in decision making. A scrutinizing history, close observation of disc appearance, and the vasculature will aid in the diagnosis of glaucoma or other entity of optic-disc cupping. SUMMARY: Optic-disc cupping is a consequence of myriad disorders. Knowledge of the anatomy and vasculature of the disc is quintessential to the understanding of how, why, when, and what type of optic-disc cupping occurs in various conditions. Cupping can be seen with neurological processes, including benign tumors, which are treatable. Patient history, visual fields assessment, and funduscopic findings are the key to unlocking the diagnosis of glaucomatous versus nonglaucomatous optic-disc cupping. As clinicians, we must remain vigilant and receptive to the findings of potentially ominous forms of nonglaucomatous optic-disc cupping.

Acute conformational changes in the optic nerve head with rapid intraocular pressure elevation: implications for LASIK surgery.

BACKGROUND AND OBJECTIVE: To investigate the effects of acute intraocular pressure (IOP) elevation on optic disc morphology. PATIENTS AND METHODS: Ophthalmodynamometry was used to increase the IOP of normal, healthy eyes. Confocal scanning laser ophthalmoscopy of the optic nerve head using the Heidelberg Retinal Tomograph II (Heidelberg GmbH, Heidelberg, Germany) and IOP measurements were obtained before, during, and after IOP elevation. RESULTS: Sixteen eyes of 16 normal volunteers (mean age, 32.8 +/- 11.9 years) were enrolled. Rim area, rim volume, cup area, cup volume, cup-to-disc ratio, mean cup depth, maximum cup depth, mean retinal nerve fiber layer (RNFL) thickness, and RNFL cross-sectional area showed significant changes during IOP elevation (all P < .05, paired t test). All measured parameters returned to their original values after pressure resolution (all P > .2) except mean RNFL thickness (P = .03). CONCLUSION: Transient elevation of IOP results in measurable alterations in optic nerve head topography.

Detecting the inner and outer borders of the retinal nerve fiber layer using optical coherence tomography.

BACKGROUND: The purpose of this study was to develop a new algorithm to detect the inner and outer borders of the retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT). METHODS: A program featuring a new algorithm was developed using a commercially available software development environment. The algorithm searches for peaks on each sampling line instead of applying conventional thresholding techniques. All circular peripapillary OCT images obtained at the New York Eye and Ear Infirmary from October 1996 to December 2000 were analyzed using the new and the commercially available algorithms. RESULTS: Four hundred one images of 98 patients were analyzed. The detection error rate (defined as number of scans with five consecutive sampling lines with disrupted RNFL borders) was significantly lower with the new algorithm (25/401 images, 6.2%) than with the commercially available algorithm (70/401 images, 17.5%) (P=0.018, chi-square). CONCLUSION: The new algorithm improved the ability of OCT to detect the borders of the RNFL.

Ultrasound biomicroscopy in uveitis-glaucoma-hyphema syndrome.

PURPOSE: To assess anterior segment anatomy in uveitis-glaucoma- hyphema syndrome. DESIGN: Retrospective case series. METHODS: Nine pseudophakic eyes (nine patients) with complete or incomplete uveitis-glaucoma-hyphema syndrome underwent ultrasound biomicroscopy. RESULTS: Ultrasound biomicroscopy revealed intraocular lens malposition in each case. Of the eight eyes with posterior chamber intraocular lenses, haptics were in contact with the iris pigment epithelium (four eyes) or the pars plicata (three eyes) or prolapsed into the angle recess near a filtration bleb internal ostium (one eye). All other posterior chamber intraocular lens haptics were located in the ciliary sulcus with the exception of two in the capsular bag. Both haptics in the eye with the anterior chamber intraocular lens had eroded into the ciliary body. CONCLUSION: By its ability to detect haptic position, ultrasound biomicroscopy can assist in elucidating the cause of uveitis-glaucoma-hyphema syndrome and in deciding on the course of treatment.