R. Morbio

Vascular risk factors for primary open angle glaucoma: The Egna-Neumarkt Study

OBJECTIVE To assess the impact of vascular risk factors on the prevalence of primary open angle glaucoma. DESIGN Population-based cross-sectional study. PARTICIPANTS Four thousand two hundred ninety-seven patients more than 40 years of age underwent a complete ocular examination in the context of the Egna-Neumarkt Glaucoma Study. INTERVENTION Ocular examinations were performed by trained, quality-controlled ophthalmologists according to a predefined standardized protocol including medical interview, blood pressure reading, applanation tonometry, computerized perimetry, and optic nerve head examination. MAIN OUTCOME MEASURES Prevalences of ocular hypertension, primary open-angle glaucoma, normal-tension glaucoma, and other types of glaucoma were determined. Correlation coefficients were calculated for the association between systemic blood pressure and age-adjusted intraocular pressure (IOP) and between age and both intraocular and systemic blood pressures. Odds ratios were computed to assess the risk of primary open-angle glaucoma and normal-tension glaucoma in relation to systemic hypertension or antihypertensive medication, blood pressure levels, diastolic perfusion pressure, and a number of other cardiovascular risk factors. RESULTS A positive correlation was found between systemic blood pressure and IOP, and an association was found between diagnosis of primary open-angle glaucoma and systemic hypertension. Lower diastolic perfusion pressure is associated with a marked, progressive increase in the frequency of hypertensive glaucoma. No relationship was found between systemic diseases of vascular origin and glaucoma. CONCLUSIONS Our data are in line with those reported in other recent epidemiologic studies and show that reduced diastolic perfusion pressure is an important risk factor for primary open-angle glaucoma.

Ultrasound biomicroscopy and intraocular-pressure-lowering mechanisms of deep sclerectomy with reticulated hyaluronic acid implant

Purpose: To evaluate the anatomic characteristics and intraocular pressure (IOP) lowering mechanisms of deep sclerectomy with reticulated hyaluronic acid implant (DS with RHAI) using ultrasound biomicroscopy (UBM). Setting: Eye Clinic, Department of Neurological and Vision Sciences, University of Verona, Verona, Italy. Methods: Thirty patients with primary open‐angle glaucoma not controlled by medical therapy had DS with RHAI in 1 eye. A complete ocular examination and UBM study were performed 1, 3, 6, and 12 months postoperatively and thereafter at 6 month intervals. Eleven parameters were evaluated, the most important of which were IOP, surgical success in lowering IOP to 21 mm Hg or less with or without additional medical therapy, UBM appearance of the site of DS with RHAI, size of the decompression space, presence of a filtering bleb and supraciliary hypoechoic area, and scleral reflectivity around the decompression space. Results: After a mean follow‐up of 11.4 months ± 4.7 (SD), the mean percentage reduction in IOP compared to preoperatively was 38% (from 26 ± 4.5 mm Hg to 16.2 ± 3.8 mm Hg; P = .0001). Twenty‐four patients (80%) had an IOP less than 21 mm Hg; however, 7 of these eyes (23%) required additional IOP‐lowering medical therapy. The operation failed in 6 patients (20%) despite additional therapy. Ultrasound biomicroscopy revealed a reduction in the size of the decompression space from 6 months postoperatively and its disappearance in 2 cases. The difference in size at the last follow‐up and at 1 month postoperatively (maximum length 2.41 ± 1.02 mm versus 3.53 ± 0.51 mm) was significant (P = .0001). At the last examination, a filtering bleb was present in 18 patients (60%), a supraciliary hypoechoic area in 18 (60%), and hyporeflectivity of the scleral tissue around the decompression space in 14 (47%). These 3 UBM characteristics were detected singly and in various combinations. The simultaneous presence of all 3 characteristics in the same eye correlated significantly with a higher surgical success rate (P = .004). Conclusions: Ultrasound biomicroscopy showed that filtering bleb formation was frequent in eyes having DS with RHAI but that it was not the only surgically induced IOP‐lowering mechanism. Increased uveoscleral and transscleral filtration may be equally important.

The Relationship between Intraocular Pressure and Glaucoma in a Defined Population

Purpose: To provide data on the prevalence of ocular hypertension and glaucoma and on the diagnostic validity of tonometry. Methods: In this cross-sectional, population-based study, 4,927 subjects over 40 years of age were examined. Each subject underwent a complete ocular examination as part of the Egna-Neumarkt Glaucoma Study. These examinations were carried out by trained, quality-controlled ophthalmologists, according to a predetermined standard protocol that included a medical interview, applanation tonometry, computerized perimetry, optic nerve head examination and other ocular measurements. The following data were recorded: mean IOP, prevalence of ocular hypertension, primary open-angle glaucoma and normal tension glaucoma. Sensitivity, specificity and the predictive value of the tonometric test, as well as the distribution of IOP in the different groups were also determined. Results: The overall prevalence of ocular hypertension, hypertensive primary open-angle glaucoma and normal tension glaucoma corresponded to 2.1, 1.4 and 0.6%, respectively. Other types of glaucoma accounted for a further 0.9%. The sensitivity and specificity of the tonometric test in recognizing glaucoma (cut-off between 21 and 22 mm Hg) were, respectively, 80.1 and 97.8%. The predictive values of the positivity and negativity of the test were 52.1 and 99.4%, respectively. Conclusions: The prevalence of ocular hypertension and glaucoma was similar to that found in several recent epidemiological studies. Tonometry alone is obviously not sufficient to ascertain or to exclude the presence of glaucoma; its diagnostic validity however is high and should never be underestimated. An elevated IOP is the main risk factor for glaucoma, with the degree of risk increasing as the level of IOP increases.

Comparison of Dynamic Contour Tonometry and Goldmann Applanation Tonometry in Deep Lamellar and Penetrating Keratoplasties

PURPOSE To compare the measurements of intraocular pressure (IOP) with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes with corneal graft and to evaluate the influence of corneal thickness (CCT), corneal curvature (CC), and astigmatism on these methods. DESIGN Prospective, observational cross-sectional study. METHODS Eighteen eyes of 18 patients after penetrating keratoplasty (PKP) and 14 eyes of 14 patients after deep lamellar keratoplasty (DLKP) underwent IOP evaluation with DCT and GAT, and measurements of CCT, CC, and astigmatism. Bland-Altman plots were used to evaluate the agreement between tonometers. Multivariate regression analysis was used to evaluate the influence of ocular structural factors and running suture on IOP measurements obtained with both tonometers. RESULTS IOP values obtained by DCT and GAT were strongly correlated in all eyes (r = .91; P < .001). DCT values measured 2.5 +/- 1.7 mm Hg higher than GAT readings (P < .001). A reduction of the mean IOP difference between DCT and GAT with an increase in IOP values (P < .001) was found. Regression analysis showed no effect of CCT, CC, astigmatism, and running suture on both DCT and GAT readings, either in DLKP or in PKP eyes. CONCLUSIONS We found a good overall correlation between both tonometers but the agreement between instruments differs in high or low IOP ranges. The wide and varying 95% limits of agreement between DCT and GAT indicates that DCT provides IOP measurements on deep lamellar and penetrating keratoplasties which can be used in the clinical practice.

Does Nerve Fiber layer thickness correlate with visual field defects in glaucoma : A study with the Nerve Fiber Analyzer

The Nerve Fiber Analyzer, a confocal scanning laser ophthalmoscope, was used to measure the thickness of the retinal nerve fiber layer (NFL) in a glaucoma population. The authors studied the correlation between NFL thickness and the perimetric defects. The NFL was found to be statistically thinner in comparison to a normal control group of subjects. The correlation between the perimetric index MD and the NFA was statistically significant only for the lower quadrant of retinal NFL. The correspondence between thinner NFL and perimetric defects was investigated.

Simultaneous bilateral acute angle-closure glaucoma in a patient with subarachnoid hemorrhage.

PurposeTo present an unusual case of simultaneous bilateral acute angle-closure (AAC) glaucoma in a patient with subarachnoid hemorrhage due to an aneurysm involving the right middle cerebral artery. MethodsA 60-year-old woman with a clinically inexplicable bilateral nonreacting mydriasis after brain surgery underwent an ophthalmologic consultancy. The bilateral mydriasis was diagnosed as an unusual clinical presentation of simultaneous bilateral AAC glaucoma. One week after the AAC was bilaterally resolved, the patient underwent echographic examination because of the outbreak of a unilateral relapsed ocular hypertensive attack that required an ultrasound biomicroscopy (UBM) to be accurately diagnosed and treated. ResultsThe bilateral AAC regressed completely after pharmacologic therapy. UBM evaluation of the eye with recurrence of the angle-closure glaucoma attack was necessary to confirm the diagnosis of unilateral relapsed angle-closure glaucoma due to an unresolved pupillary block. A viscoelastic-aided opening of the angle and peripheral surgical iridectomy were performed. UBM and tonometry were performed intraoperatively to confirm the success of the surgical treatment. ConclusionsThe UBM allowed us to identify the pupillary block as the main mechanism involved in the pathogenesis of this unusual case of simultaneous bilateral AAC glaucoma. Despite the fact that drug-induced supraciliary uveal effusion and mydriasis due to surgical anesthesia have been frequently reported to contribute to this complication, we presumed that simultaneous intravenous administration of sedative drugs and adrenergic agonists, in a patient with individual biometric predisposing factors to the angle-closure, created the anatomic conditions which induced the pupillary block with obliteration of the trabeculum.

SD-OCT Choroidal Thickness in Advanced Primary Open-Angle Glaucoma

Purpose: To assess the choroidal thickness in advanced primary open-angle glaucoma (POAG) comparing patients affected by advanced glaucoma and normal subject using spectral domain optical coherence tomography (SD-OCT). Methods: In total, 35 eyes of 35 patients affected by POAG with advanced perimetric defect (mean deviation worse than −12 dB) were prospectively enrolled and underwent a complete ophthalmologic examination, including enhanced depth imaging SD-OCT. One eye of 35 healthy subjects served as control group. Choroidal thickness was measured at the subfoveal location, at 0.5, 1.0, and 2.0 mm nasal and temporal to the fovea. Primary outcome measure was the identification of different choroidal thickness between advanced glaucoma patients and normal subjects. Results: Glaucoma and control group were homogenous for age, sex, and axial length (P>0.05 in all cases). A significant difference was found in the subfoveal choroidal thickness (SFCT) adjusted for age and axial length between glaucoma and control eyes (P=0.042); in glaucoma patients the mean adjusted SFCT was 209.90 &mgr;m compared with 234.78 &mgr;m in control subjects. Both temporal and nasal choroidal thickness measurements followed the same SFCT trend, even if only temporal ones were statistically significant. We also found that SFCT decreased with age and increased axial length (P=0.007 and 0.001, respectively). Sex and intraocular pressure did not significantly influence the choroidal thickness (P=0.87 and 0.35, respectively). Conclusions: Patients affected by advanced POAG damage have a thinner choroidal thickness compared with normal subjects, using SD-OCT. We also confirmed that age and axial length were the main factors affecting choroidal thickness in these patients.

Visual Field Defects and Normal Nerve Fiber Layer: May They Coexist in Primary Open-Angle Glaucoma?

The retinal nerve fiber layer (RNFL) is the anatomical structure most sensitive to glaucoma injury. Before a functional loss such as a visual field defect is displayed, a large number of nerve fibers can be damaged. However, there are glaucoma patients in which an apparently normal RNFL coexists with evident visual field defects. A total of 54 eyes affected with primary open-angle glaucoma were studied. Visual field was examined with the Humphrey Field Analyzer (Zeiss) using program 30-2. The Nerve Fiber Analyzer II (Laser Diagnostic Technologies) was used to study the RNFL of these patients. Mean deviation of the visual field ranged from 6 to 31 dB in all eyes that were examined. The average thickness of the RNFL ranged from 20 to 90 μm. According to our previous experience 75 μm was fixed as the cutoff between normal and pathological values of RNFL thickness. We identified 5 eyes with a RNFL thickness over 75 μm and a visual field with a mean deviation over 6 dB; 9% of the studied eyes were found to have a visual field defect with no changes in RNFL. We conclude that not all subjects have the same number of fibers at birth and that it is therefore possible to underestimate the RNFL changes. Our study illustrates that the concept of normal and altered has to be considered as a relative one for all the aspects characterizing the glaucomatous disease.

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Der diesjährige, mit sFr. 60000.– dotierte Preis der Alfred-VogtStiftung zur Förderung der Augenheilkunde wurde geteilt und zu gleichen Teilen durch die Schweizerische Ophthalmologische Gesellschaft (SOG/SSO) am 17.9.1999 in Montreux verliehen an die Herren Matthias Böhnke und Barry R. Masters, Universitäts-Augenklinik Bern, für deren Arbeit ‹‹Konfokale Mikroskopie der Kornea›› sowie an die Arbeitsgruppe Elena Korvatska, Francis L.P. Munier, Daniel F. Schorderet und Mitarbeiter, Universitäts-Augenklinik Lausanne, für deren Arbeit zur Genetik autosomal dominant vererbter Hornhauterkrankungen. Der Preis ist die höchste schweizerische Auszeichnung, die auf dem Gebiet der Augenheilkunde und ihrer Grenzgebiete verliehen werden kann. Eine Anerkennungsgabe der Alfred-Vogt-Stiftung von sFr. 10000.– ging an Herrn Josef Lang, Zürich, für seine Monographie über Stereopsis (räumliches Sehen) und in Anerkennung seiner grossen, lebenslangen Arbeit für die Schielbehandlung.