Alfonso Antón

Clinical Assessment of Stereoscopic Optic Disc Photographs for Glaucoma: The European Optic Disc Assessment Trial

PURPOSE To determine the diagnostic accuracy of judging optic disc photographs for glaucoma by ophthalmologists. DESIGN Evaluation of diagnostic test and technology. PARTICIPANTS A total of 243 of 875 invited ophthalmologists in 11 European countries. METHODS We determined how well each participant classified 40 healthy eyes and 48 glaucomatous eyes with varying severity of the disease on stereoscopic slides. Duplicate slides were provided for determining intraobserver agreement. All eyes were also imaged with the GDx with variable corneal compensation (GDx-VCC) (Carl Zeiss Meditec AG, Jena, Germany) and the Heidelberg Retina Tomograph (HRT) I (Heidelberg Engineering GmbH, Heidelberg, Germany). Diagnostic accuracies of clinicians were compared with those of the best machine classifiers. MAIN OUTCOME MEASURES Accuracy of classification, expressed as sensitivity, specificity, and overall accuracy. Intraobserver agreement (kappa). RESULTS The overall diagnostic accuracy of ophthalmologists was 80.5% (standard deviation [SD], 6.8; range, 61.4%-94.3%). The machine classifiers outperformed most observers in diagnostic accuracy; the GDx-VCC nerve fiber indicator and the HRTs best classifier correctly classified 93.2% and 89.8% of eyes, respectively. The intraobserver agreement (kappa) varied between -0.13 and 1.0 and was on average good (0.7). CONCLUSIONS In general, ophthalmologists classify optic disc photographs moderately well for detecting glaucoma. There is, however, large variability in diagnostic accuracy among and agreement within clinicians. Common imaging devices outperform most clinicians in classifying optic discs. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Mapping structural to functional damage in glaucoma with standard automated perimetry and confocal scanning laser ophthalmoscopy

PURPOSE To develop a quantitative method for analysis of the topographic relationship between structural and functional damage in patients with glaucoma. METHODS We studied 26 patients with primary open-angle glaucoma, focal optic disk damage, and focal visual field loss. The visual field was evaluated with automated perimetry, and the optic disk topography was assessed with a confocal scanning laser ophthalmoscope. Topographic measurements were calculated in 10-degree sectors and compared with a normative database (n=52). The topographic relationship of structural damage and functional loss was analyzed. RESULTS Rim area ratio was defined as the ratio of rim area in each 10-degree sector divided by the total rim area. This ratio resulted in the identification of one (46%) or more (54%) clusters of optic disk sectors as outside normal limits in all 26 patients (12 and 14 patients, respectively). Twenty-two patients (84%) with superior hemifield sensitivity loss tended to have inferior rim defects, and vice versa. Nasal visual field defects close to the horizontal midline were matched with damaged rim areas close to the vertical midline. CONCLUSIONS This mapping method allows an objective and quantitative evaluation of the optic disk and visual field in patients with glaucoma and focal damage. Although the topographic relationship between structure and function is characterized by considerable interindividual variability, the identification of certain patterns may be useful to aid in the evaluation of glaucomatous damage.

Prevalence of primary open-angle glaucoma in a Spanish population: the Segovia study.

PurposeTo determine the prevalence of primary open-angle glaucoma (POAG) in Segovia, Spain. MethodsWe conducted a cross-sectional, population-based epidemiologic study, the target population of which was residents of Segovia, Spain, aged 40 to 79 years. A sample of 569 subjects was randomly selected in a stratified manner according to gender and age groups. All participants underwent a complete ophthalmic examination that included measurement of visual acuity and refraction, tonometry, anterior segment biomicroscopy, funduscopy, stereoscopic photographs of the optic nerve head, and automated white-on-white visual field testing. Two independent observers evaluated the optic nerve photographs and visual fields. The diagnosis of POAG was established when any eye had an open angle and a glaucomatous optic nerve and glaucomatous visual field. The prevalence of POAG in the population was estimated from the prevalence in the complete sample and the patients already diagnosed at the only glaucoma service in the city. ResultsThe estimated prevalences (99% confidence interval) in the population were, respectively, 2.1% (1.9–2.3%), and 1.7% (1.6–1.8%) for POAG and ocular hypertension. The prevalence of POAG increased with age (P < 0.005) and tended to be greater (P = 0.054) in men (2.4%) than women (1.7%). ConclusionThe prevalence of POAG in this Segovia population is 2.1%, similar to that estimated in previous studies performed in predominantly Caucasian populations.

Mapping structural damage of the optic disk to visual field defect in glaucoma.

PURPOSE To evaluate the relation between the location of focal visual field defects and optic disk damage in eyes with glaucoma by short-wavelength automated perimetery and confocal scanning laser ophthalmoscopy. METHODS In 14 patients (14 eyes) with open-angle glaucoma, focal optic disk damage, and focal visual field loss, we obtain visual fields with short-wave-length automated perimetry. The short-wavelength automated perimetry visual field was divided into 21 zones, representing retinal nerve fiber layer arcuate bundles. Test points were compared with a normative database. The optic disk was assessed with a confocal scanning laser ophthalmoscope. Optic disk measurements were calculated in 10-degree sectors and compared with a normative database using a new measure, the rim area ratio, which adjusts for individual differences in disk size. RESULTS The mean number (+/-SD) of damaged visual field zones was 3.9 (+/-1.9), and the mean number of damaged rim sectors was 5.0 (+/-2.9). Focal defects on the optic disk and on short-wavelength automated perimetry were topographically related with specific damaged visual field zones corresponding to specific damaged rim sectors. CONCLUSIONS In patients with open-angle glaucoma with focal optic disk damage and focal visual field loss, defects in optic disk and short-wavelength automated perimetry are topographically related. The rim area ratio can be used to identify focal optic nerve defects.

Usefulness of optical coherence tomography parameters of the optic disc and the retinal nerve fiber layer to differentiate glaucomatous, ocular hypertensive, and normal eyes.

PurposeTo assess Stratus optical coherence tomography (OCT) original parameters for identifying glaucomatous damage and to evaluate differences among glaucomatous, ocular hypertensive, and normal eyes. DesignCross-sectional prospective study. Subjects and MethodsThe study was conducted at 2 centers. The study population consisted of 55 normal individuals, 95 patients with ocular hypertension (OHT), and 79 patients with glaucoma. Retinal nerve fiber layer (RNFL) and optic nerve head OCT protocols were used to evaluate all study participants. Measurements taken were RNFL thickness, several ratios, RNFL asymmetry between both eyes, rim volume, rim width, disc area, cup area, rim area, cup/disc (C/D) area ratio, and horizontal and vertical C/D ratios. The main outcome measures were the differences in OCT parameters among groups and the areas under the receiver operating characteristic curves (AROC). ResultsMean RNFL thickness around the disc, and superior and inferior RNFL thickness, were significantly thinner in glaucomatous eyes than in OHT or normal eyes (P<0.001). Rim parameters were significantly smaller in glaucomatous eyes than in normal (P<0.001) and OHT eyes (P=0.01). C/D ratios were significantly greater in glaucomatous eyes than in OHT (P<0.001) and normal (P<0.001) eyes. Significant differences were found between normal and OHT eyes in 7 disc parameters. No difference was found among groups in parameters describing RNFL asymmetry between both eyes. The AROC curves of the other RNFL and disk parameters ranged from 0.741 to 0.85. ConclusionsAlmost all RNFL and disc parameters showed significant differences and discriminated between glaucomatous and normal eyes. There were significant differences in some optic nerve parameters, but no RNFL parameters, between normal and OHT eyes.

Initial Clinical Experience With the CyPass Micro-Stent: Safety and Surgical Outcomes of a Novel Supraciliary Microstent.

Purpose:To evaluate safety and clinical outcomes of a novel supraciliary device, the CyPass Micro-Stent, for surgical treatment of open-angle glaucoma when implanted in conjunction with cataract surgery. Patients and Methods:Subjects (n=142) with open-angle glaucoma and cataract underwent combined phacoemulsification, with intraocular lens insertion, and microstent implantation into the supraciliary space of study eyes (n=167). Two analysis cohorts were prespecified based upon medicated baseline intraocular pressure (IOP): ≥21 mm Hg (cohort 1, n=65) or <21 mm Hg (cohort 2, n=102). Glaucoma medications were discontinued or tapered at surgery, and restarted at investigator discretion. The main postoperative outcome measures were adverse events, IOP changes, and number of IOP-lowering medications. Results:Mean±SD follow-up was 294±121 days. No major intraoperative or postoperative complications occurred. Preoperative baseline mean IOP was 20.2±6.0 mm Hg and mean number of IOP-lowering medications was 2.0±1.1. Cohort 1 showed a 35% decrease in mean IOP and a 49% reduction in mean glaucoma medication usage; cohort 2 demonstrated a 75% reduction in mean medication usage while maintaining mean IOP<21 mm Hg. For all eyes, mean IOP at 12 months was 15.9±3.1 mm Hg (14% reduction from baseline). Early and late postoperative IOP elevation occurred in 1.2% and 1.8% of eyes, respectively. Two subjects developed mild transient hyphema, and none exhibited prolonged inflammation, persistent hypotony, or hypotony maculopathy. Conclusions:CyPass Micro-Stent implantation, combined with cataract surgery, resulted in minimal complications and reduced IOP and IOP-lowering medication use at 12 months postoperatively.

Epidemiology of Refractive Errors in an Adult European Population: The Segovia Study

ABSTRACT Purpose: To determine the prevalence of refractive errors in Segovia, Spain. Methods: A cohort of 569 subjects was randomly selected in a stratified manner according to gender and age in a cross-sectional, population-based epidemiologic study, the target population of which was urban residents aged 40 to 79 years. All participants underwent an ophthalmic examination that included measurement of visual acuity (VA) and refraction, tonometry, anterior segment biomicroscopy, funduscopy, optic nerve head photography, and visual field testing. Of those, 417 subjects were enrolled who met the inclusion criteria of a phakic right eye and VA over 20/40. The prevalence of spherical errors was assessed after calculating the spherical equivalent and defining myopia as −0.5 diopters (D) or less and hyperopia as +0.50 D or more. The prevalence of astigmatism over 0.50 D was evaluated in minus cylinder form. Results: The estimated prevalences (95% confidence interval) of myopia, hyperopia, and astigmatism, in the population were 25.4% (21.5–29.8%) 43.6% (39–48.4%), and 53.5% (48.7–58.2%), respectively. No significant gender difference was found in the prevalence of any refractive errors. The prevalence of myopia or the mean value did not change significantly with age. The mean hyperopia and the mean astigmatism (p < 0.01 for both) and the prevalence increased with increasing age (p < 0.01 for both). Anisometropia of 1 D or more was present in 12.3% (49/396 subjects). Conclusion: More than 60% of the Segovia population over 40 years of age has a refractive error, with 25.4% myopic and 43.6% hyperopic. Astigmatism is present in over half of the population and the types change with age.

Comparison of retinal nerve fiber layer thickness values using Stratus Optical Coherence Tomography and Heidelberg Retina Tomograph-III.

PurposeTo evaluate the usefulness of retinal nerve fiber layer (RNFL) thickness measurements using the Heidelberg Retina Tomograph-III (HRT-III) in normal, ocular hypertensive, and glaucomatous eyes and compare the thickness measurements using HRT-III and Stratus Optical Coherence Tomography-3 (OCT-3). MethodsSixty-nine normal eyes, 60 eyes ocular hypertensive, and 111 glaucomatous were included. All participants underwent visual field, HRT-III, and OCT-3 examinations on the same day. Patients were classified into 3 groups according to intraocular pressure and visual field damage. The sensitivity/specificity of RNFL thickness measurements and RNFL thickness classifications using HRT-III and OCT-3 were calculated. The sensitivity/specificity of the height variation contour (HVC) from the HRT-III were calculated. The receiver operating characteristic curves (ROC) and areas under the ROC were plotted. Agreement was calculated using Bland-Altman method and the κ coefficient. ResultsThe RNFL thickness sensitivity/specificity were 32.4%/87%, for the HRT-III and 72.97%/81.15% for the OCT-3 in relation to the glaucoma diagnosis (least specific criteria). The RNFL thickness sensitivities/specificities were lower in early glaucoma. The areas under the ROC for RNFL measurements were 0.72 using HRT-III, 0.86 with OCT-3 (P=0.001), and 0.54 for the HVC. The RNFL classification κ coefficient was 0.36. Bland-Altman analysis confirmed that the RNFL measurements were not interchangeable. ConclusionsThe sensitivity of RNFL damage detection using HRT-III was lower compared with OCT-3, especially in early glaucoma. RNFL thickness agreement between HRT-III and OCT-3 was only fair. HVC was not useful for glaucoma detection.

Detection of visual-field deterioration by Glaucoma Progression Analysis and Threshold Noiseless Trend programs

Background: To compare the ability of Glaucoma Progression Analysis (GPA) and Threshold Noiseless Trend (TNT) programs to detect visual-field deterioration. Methods: Patients with open-angle glaucoma followed for a minimum of 2 years and a minimum of seven reliable visual fields were included. Progression was assessed subjectively by four masked glaucoma experts, and compared with GPA and TNT results. Each case was judged to be stable, deteriorated or suspicious of deterioration Results: A total of 56 eyes of 42 patients were followed with a mean of 7.8 (SD 1.0) tests over an average of 5.5 (1.04) years. Interobserver agreement to detect progression was good (mean kappa = 0.57). Progression was detected in 10–19 eyes by the experts, in six by GPA and in 24 by TNT. Using the consensus expert opinion as the gold standard (four clinicians detected progression), the GPA sensitivity and specificity were 75% and 83%, respectively, while the TNT sensitivity and specificity was 100% and 77%, respectively. Conclusion: TNT showed greater concordance with the experts than GPA in the detection of visual-field deterioration. GPA showed a high specificity but lower sensitivity, mainly detecting cases of high focality and pronounced mean defect slopes.

Patterns of optic disk damage in patients with early focal visual field loss.

PURPOSE To study the patterns of structural damage of the optic disk in patients with early focal visual field loss using a confocal scanning laser ophthalmoscope. METHODS Thirty-nine subjects with repeatable early focal visual field loss were included. The Heidelberg Retina Tomograph (Heidelberg Engineering, Heidelberg, Germany) was used to obtain topographic optic disk measurements. For analysis of structural damage, the topographic measurements were divided into 36 10-degree sectors. Sector analysis was performed using sector rim area to sector disk area ratio. Patients were assigned to one of three groups based on the measurement of the optic disk damage: (1) diffuse disk damage; (2) focal disk damage; or (3) no detectable disk damage. RESULTS Approximately half of the patients with early focal glaucomatous visual field loss showed diffuse optic disk damage, one quarter to one third had focal damage, and one sixth had no detectable damage. Optic disk area was smallest in the no-detectable-damage group (1.71 + 0.19 mm2), followed by the focal-damage group (2.06 + 0.54 mm2), and was largest in the diffuse damage group (2.29 + 0.48 mm2; P = .22). CONCLUSION In patients with early focal glaucomatous visual field loss, observable optic disk damage can be diffuse, focal, or undetectable. The Heidelberg Retina Tomograph may be capable of detecting different patterns of diffuse or focal structural damage.