A European Perspective on Costs and Cost Effectiveness of Ophthalmic Combinations in the Treatment of Open-Angle Glaucoma

Purpose

Efficacy, safety, and cost implications are important considerations when choosing an ophthalmic treatment. Fixed-combination glaucoma medications containing brimonidine 0.2% and timolol 0.5%, or dorzolamide 2% and timolol 0.5%, were compared with brimonidine 0.2% and dorzolamide 2% that were used as adjunctive therapy to timolol 0.5%.

Methods

A literature review was conducted to determine the outcome parameters of intraocular pressure reduction and tolerability after 3 months of use of brimonidine or dorzolamide, each together with timolol as a fixed-combination or in concomitant therapy. Modelled cost-minimization and cost-effectiveness analyses were performed to investigate the economic consequences of ophthalmic therapy with brimonidine, dorzolamide, and timolol from a societal perspective.

Results

The literature review found that brimonidine and dorzolamide used as fixed combinations with timolol as well as in adjunctive therapy to timolol were equally effective and safe. Furthermore, in the European countries studied, the fixed combination of brimonidine/timolol represented a less costly option when compared to the fixed combination of dorzolamide/timolol evaluated over both a 3-month and a 12-month horizon.

Conclusions

Brimonidine used as a fixed-combination therapy with timolol provided better cost value than dorzolamide/timolol in all the countries studied. For most countries, the fixed combination of brimonidine and timolol also provided better cost value than adjunctive therapy with brimonidine, which was more cost effective than adjunctive therapy with dorzolamide.

Diagnostic ability of Humphrey perimetry, Octopus perimetry, and optical coherence tomography for glaucomatous optic neuropathy

PurposeTo evaluate and compare the diagnostic accuracy of the Humphrey Field Analyzer (HFA), Octopus perimetry, and Cirrus OCT for glaucomatous optic neuropathy.MethodsEighty-eight healthy individuals and 150 open-angle glaucoma patients were consecutive and prospectively selected. Eligibility criteria for the glaucoma group were intraocular pressure ≥21 mm Hg and glaucomatous optic nerve head morphology. All subjects underwent a reliable standard automated perimetry with the HFA and Octopus perimeter, and were imaged with the Cirrus OCT. Receiver-operating characteristic (ROC) curves were plotted for the threshold values and main indices of the HFA and Octopus, the peripapillary retinal nerve fiber layer thicknesses, and the optic nerve head parameters. Sensitivities at 85 and 95% fixed-specificities were also calculated. The best areas under the ROC curves (AUCs) were compared using the DeLong method.ResultsIn the glaucoma group, mean deviation (MD) was -5.42±4.6 dB for HFA and 3.90±3.6 dB for Octopus. The MD of the HFA (0.966; P<0.001), mean sensitivity of the Octopus (0.941; P<0.001), and average cup-to-disc (C/D) ratio measured by the Cirrus OCT (0.958; P<0.001) had the largest AUCs for each test studied. There were no significant differences among them. Sensitivities at 95% fixed-specificity were 82% for pattern standard deviation of the HFA, 81.3% for average C/D ratio of OCT, and 80% for the MD of the Octopus.ConclusionsHFA, Octopus, and Cirrus OCT demonstrated similar diagnostic accuracies for glaucomatous optic neuropathy. Visual field and OCT provide supplementary information and thus these tests are not interchangeable.

Retinal Sensitivity in Patients with Type I Diabetes without Retinopathy or with Minor Retinal Changes

Objective: To evaluate the ability of short-wavelength automated perimetry (SWAP) for the detection of visual impairment in patients with type I diabetes without retinopathy or with minor retinal vascular changes. Design: Comparative cross-sectional study. Participants: 30 eyes of 30 healthy subjects and 73 eyes of 73 patients with type I diabetes mellitus were studied. Methods: Ophthalmic examination of diabetic patients showed no retinopathy or minimal changes (less than 5 microaneurisms in each eye) with no previous laser treatment. All patients were examined by means of the SWAP 24-2 strategy. Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared between both groups. Results: There were differences in the clusters of altered points between both groups (p=0.004). SWAP MD was lower in the diabetic group than in the controls (-2.89 dB vs. -0.20 dB, p<0.001). SWAP PSD also differed between both groups (2.50 dB in control group, 3.12 dB in the diabetic group, p=0.003). In the diabetic group, mean period from the onset of diabetes was 12.6±6.7 years and minimal vascular changes were observed in the retina of 18 eyes (24.7%), while 55 had no lesions (75.3%). No differences in SWAP changes were found between patients without and with minimal diabetic retinopathy. Conclusions: Retinal sensitivity assessed by SWAP is depressed in patients with type I diabetes regardless of the presence of retinal vascular changes.

[Finding of retinal nerve fiber layer hypertrophy in ataxia of Charlevoix-Saguenay patients]

PURPOSE/METHODS

To present the neuro-ophthalmology examination in 5 spastic ataxia of Charlevoix-Saguenay (ARSACS) patients showing significant increases in retinal nerve fiber layer (RNFL) thickness.

RESULTS/CONCLUSIONS

All patients showed abnormal visual fields, normal optic discs with increased visibility of RNFL in color stereo-photographs, normal examination with Heidelberg Retina Tomography instrument, and moderate to markedly increased RNFL thickness in Cirrus Optical Coherence Tomography evaluation (average thickness: 119 to 220 microns). We found evidence that RNFL hypertrophy may be an alternative funduscopic finding to the hypermyelinated retinal fibers in previous reports. A revision of ARSACS diagnostic criteria, particularly with regard to retinal alterations, is necessary.

Three-dimensional geometries representing the retinal nerve fiber layer in multiple sclerosis, optic neuritis, and healthy eyes

BACKGROUND

To represent and interpret the three-dimensional (3D) geometry and the distribution of the axonal damage to the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS) compared with healthy subjects. To analyze alterations in RNFL morphology in eyes of MS patients with or without previous episodes of optic neuritis (ON).

METHODS

MS patients (n = 122) and age-matched healthy subjects (n = 108) were enrolled. The Spectralis optical coherence tomography system was used to determine the circumpapillary RNFL thickness. The 768 RNFL thickness measurements were used to evaluate thickness measurements in patients with or without antecedent ON and to design a 3D reconstruction of the RNFL thickness representing the mechanobiologic tissue response to neurodegeneration caused by MS and ON episodes.

RESULTS

RNFL thickness was decreased in MS patients, and was higher in the MS group with previous ON. Statistical analysis and 3D RNFL reconstruction revealed greater damage to the ganglionar cells in the superonasal RNFL area (101.77 µm in MS vs. 125.47 µm in healthy subjects) and in the inferotemporal RNFL (119.05 µm in MS eyes and 149.26 µm in healthy eyes).

CONCLUSIONS

The 3D representation of RNFL thickness based on measurements allows physicians to better observe damage in the temporal areas, especially in patients with previous ON.

[Functional relationship between retinal sensitivity threshold values assessed by standard automated perimetry in glaucoma]

OBJECTIVE

To study the correlation between the sensitivity threshold values of the different points assessed by the Humphrey visual field analyzer (24-2 Swedish interactive threshold algorithm [SITA] standard strategy) in glaucoma patients.

SUBJECTS, MATERIAL AND METHODS

Prospective cross-sectorial study. One-hundred and four eyes of 104 glaucoma patients, defined by the appearance of the optic nerve head, were evaluated. Retinal threshold sensitivity points of standard automated perimetry (SA) with SITA standard 24-2 program were obtained. The upper and the lower hemifields were studied separately. Pearson correlation coefficients were calculated between the mean threshold sensitivity value at each point of the visual hemifield and the rest of the threshold points in the same hemifield.

RESULTS

Perimetric correlation maps between retinal threshold sensitivity values in the same hemifield were obtained. Most of the points showed moderate to high correlations (r≥0.65. P<0.001) with neighboring points and distant points in the same hemifield.

CONCLUSIONS

There is a functional relationship between neighboring and distant points in Humphrey Visual Field Analyzer (SITA Standard 24-2) in glaucoma patients. This correlation is related to the anatomical arrangement of ganglion cell axons. This fact enables perimetric patterns of glaucoma defects to be obtained.

Short-term changes in the optic nerve head and visual field after trabeculectomy

AIMS OR PURPOSE: To evaluate short-term changes in optic nerve head topography and visual field induced by surgical reduction of intraocular pressure.

METHODS

A prospective study was performed on 56 eyes of 56 patients with uncontrolled primary open-angle glaucoma despite maximum medical therapy, which underwent trabeculectomy. Optic nerve head evaluations by means of Heidelberg Retina Tomograph, and visual field tests were performed pre-operatively, and at 3 and 6 months after surgery. Differences in intraocular pressure, visual field indices, and Heidelberg Retina Tomograph parameters were evaluated with the t-test for paired data. A linear regression model was calculated to analyze the relationship between intraocular pressure reduction and visual field changes, and optic nerve head changes.

RESULTS

Mean intraocular pressure decreased from 24.4 ± 5.0 mm Hg to 12.1 ± 3.1 mm Hg (month 3, P<0.001), and 10.6 ± 2.8 mm Hg (month 6, P<0.001) after trabeculectomy. Mean retinal nerve fiber layer thickness (baseline, 0.19 ± 0.034; month 3, 0.24 ± 0.039, P=0.05; month 6, 0.21 ± 0.037, P=0.05) showed a statistical significant change compared with baseline values.

CONCLUSIONS

In this 6-months study, a significant increase in retinal nerve fiber layer thickness was detected after glaucoma filtration surgery.

[Ability of Heidelberg Retina Tomograph III to predict progression in patients with early glaucoma or suspected primary open-angle glaucoma]

PURPOSE

To study the ability of Heidelberg Retina Tomography III (HRT 3) measurements to predict perimetry changes in patients with early glaucoma or suspected primary open-angle glaucoma.

MATERIAL AND METHODS

One hundred and thirty two eyes with early glaucoma or suspected glaucoma with no changes in basal perimetry were prospectively selected and periodically evaluated over five years. The eyes were divided in two groups depending on the presence or absence of progression (changes in glaucoma perimetry). The association between morphometric parameters and baseline HRT 3 indices, glaucoma probability score (GPS) and Moorefield's Regression Analysis (MRA), and perimetry progression were studied using Cox multivariate regression analyses. Kaplan-Meier curves were used to illustrate the results.

RESULTS

Forty-eight eyes (36.36%) showed perimetry progression. Perimetry progression showed higher correlations with the disc area (p = 0.001), the cup area (p = 0.002) and the vertical cup disc area (p = 0.001). Multivariate regression analyses showed that eyes with baseline MRA or baseline GPA changes were at a higher risk of having perimetry abnormalities and a faster progression.

CONCLUSIONS

MRA and GPA indices are useful to predict perimetry progression in patients with early primary open-angle glaucoma or suspected glaucoma. These indices can be used as risk markers of functional progression in glaucoma.

[Relationship between standard automated perimetry and optic nerve head topography performed with the Heidelberg Retina Tomograph]

PURPOSE

To determine the correlations between optic nerve head (ONH) parameters measured with the Heidelberg Retina Tomograph (HRT), and the main outcomes of standard automated perimetry (SAP) in normal, ocular hypertensive, glaucoma suspects and glaucomatous subjects.

METHODS

Four hundred and twenty-three patients were enrolled in the study and classified into four groups depending on baseline intraocular pressure, optic nerve head morphology, and SAP results: 87 normal eyes, 192 ocular hypertensive eyes, 70 glaucoma suspects and 74 glaucomatous eyes. In the different diagnostic groups, Pearson's correlation coefficients were calculated between ONH parameters and mean deviation, pattern standard deviation (PSD), number of altered points in each quadrant of the visual field (superior-nasal, inferior-nasal, superior-temporal and inferior-temporal), number of points altered at different probability levels, and threshold values at each point of SAP.

RESULTS

In the normal and ocular hypertensive groups, only a few weak correlations were found between HRT and SAP parameters. The strength and number of significant correlations increased in the suspected glaucoma group. The glaucoma group had the strongest correlations, particularly between cup/disc ratio and rim/disc ratio with MD (r=0.479) and between rim area and PSD (r=0.444).

CONCLUSIONS

Weak to moderate correlations were found between some ONH parameters obtained with the HRT and SAP results in the glaucoma group.

[Relationship between standard automated perimetry and retinal nerve fiber layer parameters measured with laser polarimetry]

PURPOSE

To determine the relationship between the structural parameters of the retinal nerve fiber layer (RNFL) obtained by using the scanning laser polarimetry with variable corneal compensation (GDx VCC) and the results of standard automated perimetry (SAP), in normal, ocular hypertensive, preperimetric glaucomas and glaucoma subjects.

METHODS

A total of 423 eyes of 423 consecutive subjects were prospectively included in the study and classified depending on the basal intraocular pressure, optic nerve head appearance and SAP results into four groups: 87 normal eyes, 192 ocular hypertensive eyes, 70 preperimetric glaucomas and 74 glaucomatous eyes. Pearson's correlation coefficients, between mean deviation (MD), pattern standard deviation, number of points altered in each quadrant, and number of points altered at different probability levels of SAP and structural parameters of RNFL obtained by using GDx VCC, were calculated in the different diagnostic groups. In the glaucoma group correlations between the 52 points tested by 24- 2 SITA standard and GDx parameters were also calculated. Regression curves were plotted for the strongest correlations.

RESULTS

Weak or non-significant correlations were found in the normal, ocular hypertensive and preperimetric glaucoma groups. However, the glaucoma group presented weak to moderate correlations between several GDx VCC parameters and the SAP variables analysed. The strongest correlation was observed between the standard deviation TSNIT and the MD (0.460).

CONCLUSIONS

RNFL parameters measured with the GDx VCC presented weak to moderate correlations with the visual field indices and the number of altered points in the glaucoma group.

Structure-function relationship depends on glaucoma severity

BACKGROUND/AIMS

To determine the structure-function relationship throughout the different stages of glaucoma.

METHODS

SUBJECTS

228 controls and 1007 suspected, early, moderate, or advanced glaucomas. In controls, Pearson coefficient of variation (PCV) of standard automated perimetry mean sensitivity (SAP-MS) and global mean retinal nerve fibre layer thickness (RNFL, Heidelberg Retina Tomograph) were calculated. Piecewise linear regression was used to evaluate if the data were related better to two separate regression lines in all population.

RESULTS

PCV for SAP-MS and RNFL was 6.19% and 29.27%, respectively. For SAP-MS >22.42 dB (piecewise linear regression-obtained breakpoint, p<0.05), the logarithmic and linear relationships between SAP-MS and mean RNFL thickness were not different (r = 0.182, r = 0.185 respectively; p = 0.950). For SAP-MS <22.42 dB, the logarithmic and linear relationships between SAP-MS and mean RNFL thickness were not different (r = 0.353, r = 0.344 respectively; p = 0.884).

CONCLUSION

The logarithmic and linear relationships between SAP-MS and mean RNFL thickness did not differ when individuals were stratified using the piecewise linear regression-obtained cut-off point. The curvilinear relationship between the morphological and perimetric results may be due to the wide variability in normal morphology and limitations in the dynamic range of the morphological tests in cases with moderate and severe defects.

Optic nerve head changes in early glaucoma: a comparison between stereophotography and Heidelberg retina tomography

OBJECTIVE

To evaluate and compare the diagnostic accuracy of the Heidelberg retina tomograph (HRT) version 3 with that of glaucoma specialists using stereophotography in discriminating between normal eyes and patients with early glaucomatous visual field loss.

METHODS

A total of 105 eyes of 105 individuals were prospectively and consecutively recruited. The sample comprised 51 normal and 54 early glaucomatous eyes, as defined by intraocular pressure and standard automated perimetry results, regardless of optic disc appearance. Receiver operating characteristic (ROC) curves were plotted for the HRT3 parameters and a linear discriminant function (LDF) developed in our hospital. Best sensitivity-specificity pairs were compared between the HRT3 parameters, with the highest areas under the ROC curve (AUCs) and evaluation of optic disc stereophotographs. Agreement between methods for measuring vertical cup-to-disc ratio was evaluated with the Bland-Altman plot.

RESULTS

The average visual field mean deviation was -2.90 dB. The HRT3 parameters with the largest AUCs were our LDF (0.900), rim volume (0.883), and vertical cup/disk ratio (0.880), with no significant differences between these parameters. Sensitivity-specificity pairs were 79.6-100% (clinical evaluation), 83.3-86.3% (our LDF), 64.8-96.1% (final glaucoma probability score), and 68.5-90.2% (global Moorfields regression analysis).

CONCLUSIONS

The diagnostic accuracy for differentiating normal eyes from those with early visual field defects was similar between clinical evaluation of the optic disc and evaluation with the HRT3. The use of our LDF increased the sensitivity-specificity balance with respect to the HRT-provided parameters. The diagnostic accuracy of the HRT classifications was comparable to that of an experienced glaucoma specialist.

[Optic nerve head parameters as measured by confocal scanning laser (Heidelberg Retina Tomograph II) in normal, ocular hypertensive and glaucomatous subjects]

PURPOSE

To compare the optic nerve parameters measured by confocal scanning laser in normal, ocular hypertensive and glaucomatous eyes; and in groups of ocular hypertensive eyes, classification of these according to the optic nerve appearance and to short-wavelength automated perimetry (SWAP) results.

METHODS

101 eyes of 101 normal subjects, 247 eyes of 247 ocular hypertensive subjects and 102 eyes of 102 glaucomatous subjects were studied. Subjects were classified based on intraocular pressure and standard automated perimetry (AP) performance. Hypertensive subjects were classified into ocular hypertensive and preperimetric glaucoma, and into ocular hypertensive with normal SWAP and hypertensive with pathological SWAP findings. Every patient underwent evaluation of the optic nerve, AP, SWAP and confocal scanning laser ophthalmoscopy (HRT II), resulting in the acquisition of topographic parameters of the optic nerve, which were then compared between the different groups.

RESULTS

Significant differences (p<0.05) were found between normal subjects and glaucomatous eyes in all optic nerve parameters except disc area (2.23/2.1), height variation contour (0.41/0.39) and average variability (0.05/0.04). Ocular hypertensive eyes showed an overlap when compared with normal and glaucoma groups. No differences were found between normal subjects and those with ocular hypertension in mean retinal nerve fiber layer thickness (0.24/0.24) or between those with ocular hypertension and glaucoma in mean cup depth (0.28/0.3). Nevertheless, when those with ocular hypertension were segregated based on clinical evaluation of optic nerve or SWAP performance, the ability to define the presence of structural glaucoma damage improved significantly.

CONCLUSIONS

HRT enables moderate discrimination between normal, ocular hypertensive and glaucoma subjects. The use of diagnostic tests to detect early glaucomatous damage (such as short-wavelength automated perimetry) in ocular hypertensive eyes improves the ability of HRT to discriminate glaucoma.

[Diagnostic ability of GDx VCC for glaucoma diagnosis]

PURPOSE

To assess the diagnostic ability of scanning laser polarimetry (GDx VCC) to differentiate between normal and glaucomatous eyes.

METHODS

417 eyes of 417 consecutive subjects were prospectively selected. They were classified into 60 healthy controls, 218 ocular hypertensive eyes, 68 glaucoma suspects, and 71 glaucomatous eyes, depending on intraocular pressure, optic nerve head morphology and standard automated perimetry results. All underwent a scanning laser polarimetry with the GDx VCC. Retinal nerve fiber layer (RNFL) parameters of the GDx-VCC were compared among the four groups. Receiver operating characteristic (ROC) curves were plotted between normal and glaucomatous eyes. The best parameters were defined according to the area under the ROC curve and the best sensitivity/specificity balance.

RESULTS

Most parameters of GDx-VCC exhibited differences between the glaucoma group and the rest of the groups. Some parameters were also different between healthy patients and glaucoma suspects. The best parameter was the nerve fiber indicator (NFI; area under the ROC curve: 0.876). NFI, superior normalized area, and inferior normalized area yielded the highest sensitivities at 85% and 90% fixed specificity.

CONCLUSIONS

Most RNFL parameters measured with the GDx-VCC provided good diagnostic ability for open-angle glaucoma. The best GDx-VCC parameter in differentiating between normal and glaucomatous eyes was the NFI.

[Evaluation of four new discriminant functions for HRT II in glaucoma diagnosis]

PURPOSE

To assess the diagnostic usefulness of four linear discriminant functions for Heidelberg retina tomograph (HRT) II obtained in our population.

METHODS

450 eyes of 450 patients were studied. Eyes were classified as those of healthy subjects (101), those with ocular hypertension (126), those suspected to have glaucoma (121) or those with glaucoma (103). Intraocular pressure, optic nerve head appearance in stereophotographs, and standard automated perimetry results were assessed. ANOVAs among the groups were calculated for all global parameters and the 4 formulas. Receiver operating characteristic (ROC) curves were plotted for the 4 multivariate functions designed in our hospital and the areas under the ROC curves were compared. Sensitivity at 80% and 90% fixed specificities were also calculated.

RESULTS

All functions discriminated well between healthy and glaucoma suspects, and between healthy and glaucomatous eyes. At 90% fixed specificity, sensitivities ranged from 54% to 60% in differentiating between healthy and glaucoma suspects, and from 65% to 68% in discriminating between control and glaucoma subjects. No differences were found between the areas under the ROC curves of these functions.

CONCLUSIONS

The evaluated linear discriminant functions increased the diagnostic ability of HRT II isolated parameters in detecting glaucoma. These functions performed better than the HRT-provided discriminant functions.

A cost-effectiveness analysis of fixed-combination therapies in patients with open-angle glaucoma: a European perspective

OBJECTIVE

To compare the efficacy and cost implications of the use of the intraocular pressure-lowering prostaglandin analogues bimatoprost, travoprost, and latanoprost as fixed-combination therapies with timolol, a beta-adrenergic receptor antagonist.

METHODS

A decision analytic cost-effectiveness model was constructed. Since no head-to-head studies comparing the three treatment options exist, the analysis was based on an indirect comparison. Hence, the model was based on efficacy data from five randomized, controlled, clinical studies. The studies were comparable with respect to study design, time horizon, patient population and type of end point presented. The measure of effectiveness was the percentage reduction of the intraocular pressure level from baseline. The cost evaluated was the cost of medication and clinical visits to the ophthalmologist. All drug costs were market prices inclusive of value-added tax, and visit costs were priced using official physician fees. Cost-effectiveness analyses were carried out in five European countries: Spain, Italy, United Kingdom, Norway and Sweden. The time horizon for the analyses was 3 months.

RESULTS

The analysis showed that fixed-combination bimatoprost/timolol was more effective and less costly than fixed-combination travoprost/timolol and fixed-combination latanoprost/timolol in three out of the five countries analyzed. In two countries, bimatoprost/timolol was less costly than latanoprost/timolol, and cost the same as travoprost/timolol.

CONCLUSIONS

This cost-effectiveness analysis showed that the fixed combination of bimatoprost 0.03%/timolol 0.5% administered once daily was a cost-effective treatment option for patients with primary open-angle glaucoma. This study was limited by available clinical data: without a head-to-head trial, indirect comparisons were necessary. In the United Kingdom, Sweden, Norway, Italy, and Spain, from a health service viewpoint, bimatoprost/timolol was a slightly more effective as well as less costly treatment strategy when compared to both travoprost/timolol and latanoprost/timolol.

[Importance of central corneal thickness when studying ocular hypertensive eyes, glaucoma suspects and preperimetric glaucomatous eyes]

PURPOSE

To compare the central corneal thickness, measured with an ultrasound pachymeter, in normal subjects, those with ocular hypertension, glaucoma suspects and patients with preperimetric glaucoma.

METHODS

61 normal eyes (control group), 131 eyes with ocular hypertension, 62 glaucoma suspects (optic nerve head morphology compatible with glaucoma) and 36 patients with preperimetric glaucoma (abnormal short-wavelength automated perimetry) were prospectively and consecutively selected. Scatter plots of central corneal thickness, against the intraocular pressure values were calculated for each of the study groups. Ultrasound pachymetry measurements were compared between those with normal eyes and the other groups.

RESULTS

Ocular hypertensive subjects had higher pachymetry values than the control group (p=0.009). No differences were found in the central corneal thickness between normal eyes and those who were glaucoma suspects, and between normal and preperimetric glaucomatous eyes. A mild direct logarithmic correlation was evident between central corneal thickness and the Goldmann tonometry result in the ocular hypertensive group.

CONCLUSIONS

Ocular hypertensive subjects had thicker corneas than the other groups studied. Glaucoma suspects and preperimetric glaucoma patients had similar corneal thickness to the control group.

[Correlation between standard automated perimetry global indices and Heidelberg Retina Tomograph II parameters]

PURPOSE

To correlate the optic nerve head topographic parameters measured by the Heidelberg Retina Tomograph II (HRT) with the perimetric indices of standard automated perimetry (SAP).

METHODS

This study included 101 normal subjects, 247 ocular hypertensive eyes (increased intraocular pressure with normal SAP) and 102 glaucomatous subjects (IOP above 21 mm Hg and abnormal standard automated perimetry). Only one eye was randomly chosen from each subject for the study. The visual field was evaluated by means of Humphrey Field Analyzer (24-2 full threshold strategy). The HRT II (Heidelberg Engineering) was used to acquire and measure the optic disc topographic parameters. Pearson correlations between topographic data and perimetric indices were performed for the total sample and each group of patients. The distribution of values obtained in the samples was normal.

RESULTS

A significant correlation was found between several optic disc parameters and the global indices of SAP. Rim area, rim volume, cup/disc area ratio, rim/disc area ratio, cup shape measurement, RNFL cross-sectional area, and discriminant functions FSM and RB, showed the strongest correlation with the visual field indices in the total and glaucoma groups (RIM AREA: total group: r=0.32; p=4.14x10(-11)/glaucoma group: r=0.28; p=0.004. RIM VOLUME: total group: r=0.26; p=1.55x10(-7)/glaucoma group: r=0.26; p=0.006). The ocular hypertensive group showed few significant correlations.

CONCLUSIONS

The correlations found between standard automated perimetry and HRT defined topographic parameters allow a better understanding of glaucomatous damage and make decision-making easier.

[Relationship between standard automated perimetry and HRT, OCT and GDx in normal, ocular hypertensive and glaucomatous subjects]

PURPOSE

To determine the correlations between structural parameters of the optic nerve head and the retinal nerve fiber layer (RNFL) obtained by using a Heidelberg Retina Tomograph II (HRT II), optic coherence tomography (OCT), and laser polarimetry (GDX-VCC) and the perimetric indices of standard automated perimetry (SAP) in normal, ocular hypertensive and glaucomatous subjects.

METHODS

Three hundred and eighty-nine patients were enrolled in the study and classified into three separate groups: 43 with normal eyes, 274 with ocular hypertensive eyes and 72 with glaucomatous eyes. Subjects were classified according to the basal intraocular pressure and the SAP results. Pearson's correlation coefficients were calculated between the global perimetric indices, mean deviation (MD) and pattern standard deviation (PSD), and structural parameters of the RNFL and optic disc obtained by using HRT II, OCT and GDX-VCC in the different diagnostic groups.

RESULTS

Mild to moderate correlations were found between the structural parameters measured by HRT, OCT and GDX and the global perimetric indices, in the glaucoma group. Mild or no significant correlations were found in the normal and ocular hypertensive groups. Correlations were stronger for MD than for PSD. Parameters based on the study of the retinal nerve fiber layer showed stronger correlations than those based on the study of the optic nerve head.

CONCLUSIONS

The relationship between structural and functional measurements in glaucoma is weak and therefore the results of these ancillary tests should be interpreted together to increase diagnostic accuracy.

[Retinal toxicity following chloroquine therapy]

CASE REPORT

Two cases of bilateral ocular toxicity following chloroquine therapy in two women with systemic lupus erythematosus are presented.

DISCUSSION

Retinal toxicity due to chloroquine is an uncommon iatrogenic disease. It is dose-dependent. New cases are still being described despite the application of ophthalmic screening techniques.

[Diagnostic ability of stratus optical coherence tomography (OCT) in pre-perimetric glaucoma diagnosis]

OBJECTIVE

To compare retinal nerve fiber layer (RNFL) measurements performed with Stratus OCT 3000 in normal, ocular hypertensive, pre-perimetric and glaucomatous eyes.

METHODS

98 normal subjects, 156 ocular hypertensives with short-wavelength automated perimetry (SWAP), 21 ocular hypertensives with altered SWAP (pre-perimetric glaucoma) and 66 glaucomatous eyes were included in the study. Diagnostic groups were classified based on intraocular pressure, optic nerve head appearance, achromatic automatic perimetry and SWAP. RNFL parameters were obtained using a Stratus OCT 3000 (Humphrey Zeiss instruments). RNFL measurements were compared among the groups.

RESULTS

RNFL average thickness, superior, inferior and nasal quadrant thickness, and each 12 clock-hour positions except for H9, H10 and H11 showed significant differences between glaucomatous and pre-perimetric glaucoma eyes. RNFL average thickness, inferior quadrant and H10 clock-hour position showed significant differences between normal and ocular hypertensive subjects. Pre-perimetric glaucomas and ocular hypertensives showed differences in H11 clock-hour position exclusively.

CONCLUSION

RNFL measurements performed using Stratus OCT showed differences between the study groups. OCT may be as useful as SWAP in early glaucoma diagnosis.

[Diagnostic usefulness of optical coherence tomography (OCT), scanning laser tomography (HRT-II) and laser polarimetry (GDx) in open-angle glaucoma]

PURPOSE

To evaluate the diagnostic ability of three digital imaging technologies (HRT-II, OCT and GDx VCC) in detecting glaucomatous damage.

METHODS

A total of 427 eyes from 427 subjects were included in this cross-sectional study. Each subject was classified as healthy, ocular hypertensive or glaucomatous, according to intraocular pressure levels, standard automated perimetry and optic disc morphology. All of them underwent examination by means of HRT, OCT and GDx VCC. Receiver operating characteristic (ROC) curves were plotted and sensitivities at fixed specificities (85% and 95%) were calculated for each parameter assessed.

RESULTS

The parameters with the higher diagnostic ability were: FSM discriminant function from HRT-II (AUC=0.899), retinal nerve fiber layer average thickness from OCT (AUC=0.929) and NFI from GDx VCC (AUC=0.879), with no statistically significant differences between them.

CONCLUSION

The HRT-II, OCT and GDx VCC provide measurements of the retinal nerve fiber layer and the optic nerve head with high discriminating ability in open-angle glaucoma.

[Reproducibility of optic nerve head and retinal nerve fiber layer thickness measurements using optical coherence tomography]

PURPOSE

To evaluate the reproducibility of repeated quantitative measurements of optic nerve head topography and retinal nerve fiber layer thickness.

METHODS

This study included 32 normal subjects, 41 patients with ocular hypertension and 33 patients with glaucoma. The study groups were defined by the intraocular pressure levels, optic disc stereo-photographs and perimetric performance. Optic disc and retinal nerve fiber layer assessments were performed by ocular coherence tomography (OCT III, Zeiss Instruments). OCT examination was repeated three times in each subject and the coefficient of variability was elaborated for each parameter and group of the study, and compared among them.

RESULTS

The average retinal nerve fiber layer thickness measurement showed the best reproducibility figures with a coefficient of variability of 5.9%. The inferior quadrant and the 10, 6 and 7 clock-hours (coefficients of variability 6.3%, 7.4%, 7.5% and 8.6% respectively) showed higher reproducibility. The optic nerve head assessment showed the best reproducibility for the cup-to-disc ratios (vertical, horizontal and area ratios), with a coefficient of variability of 5.0%, 4.2% and 6.6% respectively. Although differences among groups were barely statistically significant, the glaucoma group showed coefficients of variability higher than the other two groups.

CONCLUSIONS

Optic nerve head analysis and retinal nerve fiber layer thickness can be reproducibly assessed by OCT. The reproducibility of the device supports its potential use for ocular hypertension follow-up, although its use in glaucoma patients may present difficulties in some parameters.

[Sector-based analysis of the distribution of the neuroretinal rim by confocal scanning laser in the diagnosis of glaucoma]

PURPOSE

To evaluate the diagnostic ability of the Moorfields regression analysis (MRA; neuroretinal rim sector-based analysis) by means of confocal scanning laser.

METHODS

200 eyes were included in this study: 101 normal subjects and 99 glaucoma patients (standard automated perimetry with glaucomatous defects -MD or CPSD with p<0.02 or a cluster of three or more points with p<0.05 or a cluster of two or more points with p<0.01 or abnormal Glaucoma Hemifield Test). All subjects underwent a full ophthalmic evaluation, visual field evaluation by means of a Humphrey Field Analyzer, 24-2 full threshold strategy, and optic disc topography by Heidelberg retina tomograph (HRT-II). The outcome parameters were sensitivity and specificity of the MRA for each sector.

RESULTS

The highest sensitivity in detecting structural defects based on MRA (p<0.05) was observed in the nasal-superior sector (48%) and nasal-inferior sector (45%); however the highest specificity was found in the temporal-superior (98%) and inferior (98%) sectors. The highest sensitivity for MRA (p<0.01) was found in the temporal-inferior sector (31%) and nasal-superior sector (30%) while the temporal-superior and inferior-sectors showed the highest specificity (100%). The diagnosis of glaucoma based on the presence of any sector alteration showed sensitivity figures of 67% with p<0.05 and 46% with p<0.01 and specificity values of 84% with p<0.05 and 96% with p<0.01.

CONCLUSIONS

The analysis of the distribution of the neuroretinal rim by means of HRT-II contributes effectively to the diagnosis of glaucoma based on perimetry in a sample derived from a Spanish population.

[Benefit of scanning laser ophthalmoscopy for detecting retinal nerve fiber layer defects in patients with intraocular hypertension]

PURPOSE

To compare the ability to identify RNFL alterations between standard images and SLO images in a group of patients suffering from ocular hypertension.

METHODS

We evaluated RNFL in sixty patients with ocular hypertension and with normal perimetry, by using standard photography and SLO. Two different independent observers evaluated the images on two different ocassions.

RESULTS

We studied 118 eyes, twelve eyes were rejected because of the low quality of the images. Four cases of diffuse atrophy and five patients with wedge shaped defects were observed using both methods. Statistical analysis showed no differences between both exploration techniques or between observers.

CONCLUSIONS

RNFL study with SLO seems to be at least as reliable as standard photography as a method to evaluate RNFL defects. SLO has also proved to be much easier, and faster than traditional methods.

Glaucomatous damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects

PURPOSE

To determine the glaucomatous visual field damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects, and to compare the frequency of diffuse visual field losses and localized defects.

METHODS

157 eyes of 157 ocular hypertensive subjects who met the selection criteria (intraocular pressure greater than 21 mm Hg and normal standard visual fields) were studied. SWAP was done with a modified Humphrey Field Analyzer. Total (TD) and Pattern Deviation (PD) probability maps were calculated for SWAP. The frequency of abnormlities in the TD and PD were determined, analyzing the visual field loss components.

RESULTS

The involvement of the test points was more frequent on the TD plots than on the PD plots for all levels of defects (p< 0.001). The glaucomatous defects also showed certain topographical distribution.

CONCLUSIONS

A diffuse sensitivity component of visual field loss was found at all SWAP defect depths in glaucoma suspects.

An in vitro system from Plasmodium falciparum active in endogenous mRNA translation

An in vitro translation system has been prepared from Plasmodium falciparum by saponin lysis of infected-erythrocytes to free parasites which were homogeneized with glass beads, centrifuged to obtain a S-30 fraction followed by Sephadex G-25 gel filtration. This treatment produced a system with very low contamination of host proteins (<1%). The system, optimized for Mg2+ and K+, translates endogenous mRNA and is active for 80 min which suggests that their protein factors and mRNA are quite stable.