Profile of Lipoprotein Subclasses in Chinese Primary Open-Angle Glaucoma Patients

To investigate the plasma lipoprotein subclasses in patients with primary open-angle glaucoma (POAG), a total of 20 Chinese POAG patients on intraocular pressure (IOP)-lowering treatment and 20 age-matched control subjects were recruited. Based on the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), the study subjects were divided into elevated- and normal-level subgroups. The plasma lipoprotein, lipoprotein subclasses, and oxidized LDL (oxLDL) levels were quantitatively measured. The discrimination potential of the lipoproteins was evaluated using the area under the receiver operating characteristic curve (AUC), and their correlation with clinical parameters was also evaluated. Compared to the control subjects with elevated TC and/or LDL-C levels, the levels of TC, LDL-C, non-high-density lipoprotein cholesterol (non-HDL), LDL subclass LDL3 and small dense LDL (sdLDL), and oxLDL were significantly higher in POAG patients with elevated TC and/or LDL-C levels. No differences in any lipoproteins or the subclasses were found between the POAG patients and control subjects with normal TC and LDL-C levels. Moderate-to-good performance of TC, LDL-C, non-HDL, LDL3, sdLDL, and oxLDL was found in discriminating between the POAG patients and control subjects with elevated TC and/or LDL-C levels (AUC: 0.710-0.950). Significant negative correlations between LDL3 and sdLDL with retinal nerve fiber layer (RNFL) thickness in the superior quadrant and between LDL3 and average RNFL thickness were observed in POAG patients with elevated TC and/or LDL-C levels. This study revealed a significant elevation of plasma lipoproteins, especially the LDL subclasses, in POAG patients with elevated TC and/or LDL-C levels, providing insights on monitoring specific lipoproteins in POAG patients with elevated TC and/or LDL-C.

Choroidal vascular index in patients with open angle glaucoma and preperimetric glaucoma

PURPOSE

To evaluate choroidal structural changes in glaucoma using choroidal vascularity index (CVI) compared to healthy subjects.

METHODS

This retrospective study included 56 patients with open angle glaucoma (OAG), 50 patients with preperimetric glaucoma (PPG) and 50 age-matched healthy eyes. Choroidal images were binarized into luminal area (LA) and stromal area. CVI was defined as the ratio of LA to total circumscribed choroid area (TCA). Mean choroidal thickness (CT) and mean CVI between glaucoma patients and healthy subjects were compared.

RESULTS

OAG and PPG eyes showed smaller LA (0.45 ± 0.13 ㎟ vs. 0.47 ± 0.11 ㎟, p = 0.04). In multivariate regression analysis, CVI of both OAG (64.34±0.19%, p = 0.001) and PPG (65.37±0.15%, p = 0.001) were significantly lower than healthy eyes (68.81±0.14%).

CONCLUSION

Eyes with glaucoma demonstrated reduced CVI compared with healthy eyes. CVI may be a potential noninvasive tool for studying vascular dysfunction in glaucoma.

Ellipsoid Zone Change According to Glaucoma Stage Advancement

PURPOSE

To compare retinal photoreceptor ellipsoid zone (EZ) intensity between normal eyes and those with different stages of glaucoma.

DESIGN

Retrospective cross-sectional study.

METHODS

The study included 37 normal, 38 preperimetric glaucoma, 39 mild-to-moderate glaucoma (visual field [VF] mean deviation [MD]: -7.7 ± 2.0 dB), and 36 severe glaucoma eyes (VF MD: -17.8 ± 3.2 dB). The subjects underwent high-resolution horizontal and vertical line scans through the fovea by spectral-domain optical coherence tomography (SD-OCT). Image processing software was employed to quantify the intensity of the first and second hyperreflective bands corresponding with the external limiting membrane (ELM) and EZ. In order to account for the brightness variation among scans, the relative EZ intensity as the ratio of the second to first reflective band (EZ/ELM) was determined.

RESULTS

The relative EZ intensity in severe glaucoma eyes was significantly lower than in mild-to-moderate glaucoma eyes (2.46 ± 0.38 vs 3.15 ± 0.43, P < .001); also, it was lower in mild-to-moderate than in preperimetric glaucoma eyes (3.15 ± 0.43 vs 3.86 ± 0.44, P < .001). However, the comparison between preperimetric glaucoma and normal eyes showed no significant difference (3.86 ± 0.44 vs 4.06 ± 0.40, P = .751). In 75 glaucomatous eyes with VF defect, there was a significant correlation between relative EZ intensity and VF MD (r = 0.83 and P < .001).

CONCLUSIONS

According to SD-OCT, relative EZ intensity reduction occurs in the mild-to-moderate and severe glaucoma stages. These findings suggest, at least provisionally, that in the course of glaucoma progression, mitochondrial changes in the inner segments of photoreceptors occur. Further investigation is warranted to evaluate the potential clinical significance of EZ intensity reduction in glaucoma.

Evaluation of the Brusini Glaucoma Staging System for Follow-Up in Glaucoma

Background

Brusini developed a new interpretation system for Octopus and Humphrey automated perimeters that is based on mean defect (MD) and corrected loss variance (CLV) or corrected pattern standard deviation (CPSD). This study tested the performance of Brusini's glaucoma staging system (GSS) in staging and follow-up.

Methods

Retrospectively, 610 visual fields of 64 eyes of open-angle glaucoma patients were analyzed with Brusini GSS and compared with Aulhorn-Karmeyer stages and by PeriData 7.0 trend analysis.

Results

Follow-up was comparable to PeriData 7.0 trend analysis in 97%. Change was observed in 41% of eyes, i.e., initial improvement (19% eyes), deterioration (16%), and after an initial improvement, either deterioration (11%) or a stable period (5%). No change was seen in 59% of the eyes, of which 30% showed small and 19% high long-term fluctuation (LF) due to fatigue effect, poor cooperation of patient, impaired reliability, or short-term fluctuation (SF) greater than 1.7 dB. However, for 8% of the eyes there was no apparent reason for high LF.

Conclusions

Brusini GSS is useful for staging and recommended for follow-up evaluation of visual fields in glaucoma.

Simplifying "target" intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma

Lowering of intraocular pressure is currently the only therapeutic measure for Glaucoma management. Many longterm, randomized trials have shown the efficacy of lowering IOP, either by a percentage of baseline, or to a specified level. This has lead to the concept of 'Target" IOP, a range of IOP on therapy, that would stabilize the Glaucoma/prevent further visual field loss, without significantly affecting a patient's quality of life. A clinical staging of Glaucoma by optic nerve head evaluation and perimetric parameters, allows a patient's eye to be categorized as having - mild, moderate or severe Glaucomatous damage. An initial attempt should be made to achieve the following IOP range for both POAG or PACG after an iridotomy. In mild glaucoma the initial target IOP range could be kept as 15-17 mmHg, for moderate glaucoma 12-15 mmHg and in the severe stage of glaucomatous damage 10-12 mmHg. Factoring in baseline IOP, age, vascular perfusion parameters, and change on perimetry or imaging during follow up, this range may be reassessed over 6 months to a year. "Target" IOP requires further lowering when the patient continues to progress or develops a systemic disease such as a TIA. Conversely, in the event of a very elderly or sick patient with stable nerve and visual field over time, the target IOP could be raised and medications reduced. An appropriate use of medications/laser/surgery to achieve such a "Target" IOP range in POAG or PACG can maintain visual fields and quality of life, preventing Glaucoma blindness.

Estimation of the Disc Damage Likelihood Scale in primary open-angle glaucoma: the Glaucoma Stereo Analysis Study

Purpose

The Glaucoma Stereo Analysis Study (GSAS), a cross-sectional multicenter collaborative study, used a stereo fundus camera (nonmyd WX) to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients. We examined the associations between the Disc Damage Likelihood Scale (DDLS), a grading system for estimating glaucomatous ONH damage, and each parameter.

Methods

The study included 187 eyes of 187 patients with primary open-angle glaucoma or normal-tension glaucoma. ONH morphological parameters including the DDLS stage were calculated with prototype analysis software. Three independent graders classified each optic disc appearance into four different types: focal ischemic, myopic glaucomatous, senile sclerotic, and generalized enlargement. The correlations between the DDLS and patient characteristics or each ONH parameter were analyzed with Spearman’s rank correlation coefficient.

Results

The DDLS was correlated positively with baseline intraocular pressure and visual field pattern standard deviation, and negatively with visual field mean deviation. The DDLS was strongly correlated with vertical cup-to-disc ratio and horizontal cup-to-disc ratio positively, and with minimum rim-disc ratio negatively. The mean DDLS stage in the myopic glaucomatous type tended to be higher than the scores in other types.

Conclusion

The DDLS obtained through three-dimensional ONH analysis correlates well with the severity of glaucomatous ONH and visual field damage.

Characteristic correlations of the structure-function relationship in different glaucomatous disc types

PURPOSE

To investigate the influence of the optic disc type on the overall and regional correlation between structure and function in open angle glaucoma (OAG).

METHODS

We divided 144 eyes of 144 patients with OAG into four groups according to Nicolela et al.'s classification of optic disc type: focal ischemic (FI), myopic glaucomatous (MY), senile sclerotic (SS), and generalized enlargement (GE). We measured the circumpapillary retinal nerve fiber layer thickness (cpRNFLT) with the 3D OCT-2000 and the mean deviation (MD) with the Humphrey Field Analyzer in each group and determined the influence of the disc type on these parameters with the Spearman rank correlation.

RESULTS

We found that cpRNFLT and MD were significantly correlated in the MY (r = 0.61, P < 0.001), GE (r = 0.62, P < 0.001), and SS groups (r = 0.52, P = 0.002), but not in the FI group (r = 0.25, P = 0.130). The region of the optic disc with the highest correlation coefficient between structure and function differed according to the disc type.

CONCLUSIONS

The correlation between cpRNFLT and MD varied according to the optic disc morphology in OAG. This suggests that different disc types have characteristic regional variations in the correlation between structure and function. The disc type should therefore be considered in investigations of the correlation between structure and function in glaucoma.

Direct cost and predictive factors for treatment in patients with ocular hypertension or early, moderate and advanced primary open-angle glaucoma: the CoGIS study in Germany

BACKGROUND

The main objectives of this analysis were to assess the treatment costs and to identify major cost drivers and factors predicting direct costs in German patients with ocular hypertension (OHT) or primary open-angle glaucoma (POAG).

METHODS

This non-interventional cross-sectional study was conducted in two university hospitals and 13 ophthalmology practices in Germany regions (Bavaria, Rhineland-Palatinate, North Rhine-Westphalia, Hamburg and Mecklenburg-Western Pomerania) between May 2009 and January 2010 to assess resource utilisation in patients with OHT (ICD-10: 40.0) or POAG (ICD-10: 40.1) at early, moderate or advanced stages, according to the European Glaucoma Society classification Guidelines. Treatment patterns and direct costs were evaluated retrospectively for 5 years. Resource utilisation data (medication, hospitalisation, outpatient surgery, visits to ophthalmologists) were abstracted from the charts, and unit costs were applied to estimate direct costs per year (in Euros, 2009), calculated from the perspective of the statutory health insurance in Germany (Gesetzliche Krankenversicherung). Factors predicting costs were assessed in multivariate regression analysis.

RESULTS

One hundred and fifty-four patients (17.5% OHT, 27.9% early, 22.7% moderate, and 31.8% advanced POAG), on average 67 years old (SD 11) were included in the study. Average total annual direct costs per patient for OHT were <euro>226 (SD 117), for early POAG <euro>423 (SD 647), moderate <euro>493 (SD 385) and advanced POAG <euro>809 (SD 877). Glaucoma-related medications and hospitalisation represented the two major components of direct costs, increasing with the progression of glaucoma. In addition to treatment switches (p = 0.0001), factors predictive of an increase in total direct costs included the number of hospital interventions (p < 0.0001), disease-state changes since the start of treatment (p = 0.05), and current disease state (p = 0.05).

CONCLUSIONS

Direct costs of treatment are higher in glaucoma compared to OHT and further increase in more severe glaucoma states. Additional treatment changes are major contributing factors to the increased treatment costs of glaucoma. If intraocular pressure can be controlled over the long term, progression to moderate and advanced states avoided, and patients remain on initial treatments, treatment costs could decline due to reduced and less expensive healthcare resource utilisation.

Performance of time-domain and spectral-domain Optical Coherence Tomography for glaucoma screening

Purpose

To investigate the measures of validity for selective or population screening of the time-domain Stratus and the spectral-domain Cirrus Optical Coherence Tomography (OCT) imaging techniques in a population-based sample and in clinical glaucoma patients at different stages of glaucoma.

Patients and methods

A random sample of 307 subjects living in two rural areas in southern Sweden, and a random sample of 394 clinical glaucoma patients were selected. A large battery of examinations, including Stratus and Cirrus OCT was performed. OCT retinal nerve fibre layer (RNFL) thickness analyses for average thickness, quadrant and clock-hour sectors were compared with normative significance limits available in the instruments.

Results

The population-based sample included 129 healthy and nine glaucoma subjects, and the sample of clinical glaucoma patients included 138 patients. Specificity and positive predictive values were generally better with Stratus than for Cirrus, and sensitivity was generally better with Cirrus. With the average RNFL thickness parameter, Stratus reached 100% specificity and a positive predictive value of 100% and 68% sensitivity in the whole group of the clinical glaucoma patients, but sensitivity was only 28% among the earliest stage glaucoma patients. Sensitivity increased considerably when relying on the quadrant sector parameter, while specificity decreased only marginally.

Conclusion

Stratus, with high specificity and positive predictive values, seemed to be best of choice for screening purposes, while Cirrus, with high sensitivity, was the better choice for early detection.

Risk factors for incident open-angle glaucoma: a population-based 20-year follow-up study

PURPOSE

To study the effect of potential risk factors on the development of open-angle glaucoma (OAG) in a population in which pseudoexfoliation (PEX) is a common finding.

METHODS

In 1984-1986, a population-based survey of 760 people aged 65-74 years was conducted in the municipality of Tierp, Sweden. From 1988 to 2006, a follow-up study of the 530 people with normal visual fields has been in progress. To increase the cohort, 273 ophthalmic outpatients were enroled. Reliable visual fields were available for 679 people, representing 6 126 person-years at risk. A time-weighted mean intraocular pressure (IOP) for all visits was calculated.

RESULTS

Sixty-four subjects developed definite OAG, 29 of whom were exposed to PEX. Risk factors associated with OAG were higher age, a positive family history, increased IOP and PEX. The age-standardized rate ratio (SRR) was 14.8 times (95% confidence interval [CI] 7.92-27.8) greater in subjects with mean IOP ≥ 20 mmHg than in those with mean IOP <20 mmHg. When subjects with IOP < 20 mmHg at baseline were affected by PEX, the SRR increased 5.01-fold (95% CI 1.97-12.8), compared with the unaffected group. However, when mean IOP at follow-up was taken into account, there was no relationship between OAG and PEX as a distinct risk factor. Among participants in the population survey, 69% of all cases were attributable to a mean IOP ≥ 20 mmHg.

CONCLUSION

Increased IOP and PEX were serious risk factors for incident OAG. The effect of PEX was mediated by increased IOP.

Diagnostic classification of retinal nerve fiber layer measurement in myopic eyes: a comparison between time-domain and spectral-domain optical coherence tomography

PURPOSE

To evaluate and compare the diagnostic classification of retinal nerve fiber layer (RNFL) measurement between time-domain and spectral-domain optical coherence tomography (OCT) in myopic eyes.

DESIGN

Prospective, observational study.

METHODS

A total of 97 eyes from 97 healthy myopic subjects were included. The RNFL in each eye was imaged sequentially with the Stratus OCT and the Cirrus HD-OCT (Carl Zeiss Meditec). With reference to the built-in normative database, the number of abnormal diagnostic classifications (borderline or outside normal limits) in each OCT device was analyzed and compared using the likelihood ratio chi-square test. Multiple logistic regression analysis was performed to evaluate factors associated with abnormal diagnostic classification.

RESULTS

The Cirrus HD-OCT classified a significantly higher percentage of eyes as outside normal limits/borderline in at least 1 clock hour (Stratus, 14.4%/24.8%; Cirrus, 21.6%/34.1%; all P < .01). RNFL measurement at 1 (23.6%) and 2 o'clock (23.5%) of all eyes was the most frequent location classified as abnormal by the Cirrus HD-OCT and the Stratus OCT, respectively. Eyes with smaller optic disc and longer axial length were more likely to have abnormal diagnostic classification.

CONCLUSIONS

In myopic eyes, Cirrus HD-OCT was more likely to have abnormal diagnostic classification than the Stratus OCT.

[Is normal-tension glaucoma different from primary open-angle glaucoma]

Based on the clinical consideration, Chinese glaucoma specialist reached a consensus (2008) that normal-tension glaucoma (NTG) is a subtype of primary open-angle glaucoma (POAG), and the dividing line is whether the intraocular pressure (IOP) more than 21 mm Hg or not. But it is still a controversial problem in the world that whether NTG is different from POAG or not. Some studies have confirmed that the pathogenesis of optic neuropathy, clinical features, risk factors for glaucomatous optic neuropathy progression and treatment strategy in NTG are different from those of POAG, indicating that they may be two different disorders.

Diagnostic accuracy of Heidelberg Retina Tomograph III classifications in a Turkish primary open-angle glaucoma population

PURPOSE

This study aimed to evaluate the diagnostic accuracy of Moorfields regression analysis (MRA) and the glaucoma probability score (GPS) in primary open-angle glaucoma (POAG) and to measure the level of agreement between the two algorithms in classifying eyes as normal or abnormal in a Turkish population.

METHODS

We prospectively selected 184 healthy subjects and 158 subjects with POAG, who underwent an ophthalmological examination, visual field analysis and imaging with the Heidelberg Retina Tomograph II, using HRT III software, Version 3.0. The diagnostic accuracies of the two classifications were measured when the borderline was taken as either normal (highest specificity criteria) or abnormal (highest sensitivity criteria). The agreement between them was calculated using the unweighted kappa (kappa) coefficient.

RESULTS

Optic nerve head topographic parameters showed statistically significant differences between the control and POAG groups (p < 0.001). The parameters with the highest area under the receiver operating characteristic curves were global GPS (0.86), cup : disc area (0.85), rim : disc area (0.85) and vertical cup : disc (0.85). According to the highest specificity criteria, MRA had a sensitivity of 67.7% and a specificity of 95.1%, whereas the GPS had a sensitivity of 70.9% and a specificity of 88.0%. According to the highest sensitivity criteria, MRA had a sensitivity of 81.0% and a specificity of 75.0%, whereas the GPS had a sensitivity of 89.2% and a specificity of 57.6%. A moderate agreement of 68% (233 eyes) with a kappa coefficient of 0.51 was found between MRA and the GPS.

CONCLUSIONS

The GPS automated classification showed similar sensitivity to MRA, but considerably lower specificity, when applied in a Turkish population.

[Effect of vasoactive drugs on visual functions and ocular hemodynamics in patients with primary open-angle glaucoma]

The effect of cavinton forte on visual functions and ocular hemodynamics was studied in patients with primary open-angle glaucoma (POAG). Fifty-three patients (97 eyes) aged 45 to 75 years (mean age 66.3 +/- 3.7 years) who had POAG were examined. A study group comprised 38 patients (67 eyes, including 24 with Stage Ia POAG, 27 with Stage IIa, 16 with Stage IIIa). All these patients took cavinton forte (10 mg) thrice daily for 2 months. A control group consisted of 15 patients (30 eyes) receiving no vasoactive agents. In these patients, intraocular pressure was normalized and it was in the range of 15 to 21 mm Hg after Goldmann. The use of the vasoactive drug cavinton forte improved and stabilized visual functions in POAG patients with normalized intraocular pressure, which is particularly important with advanced POAG. Increased blood flow velocity in the ocular arteries after a course of therapy with cavinton forte suggests a better retinal blood supply, which is a favorable marker for the prediction of the disease.

Risk Factors and Open-angle Glaucoma: Classification and Application

Decades of epidemiologic research into open-angle glaucoma have elucidated several risk factors related in some way to the disease. As more and more risk factors are identified, however, assessing their individual and collective contributions in a particular patient is becoming increasingly complicated. To help organize our knowledge of risk in glaucoma we first review some concepts of risk and then propose a scheme that places known risk factors into categories (state of the individual, ocular anatomy and physiology, signs of disease, non-glaucoma medications, and personal behaviors) and also indicates how each factor interacts with disease (incidence, prevalence, progression, therapy.) We also describe methods for using risk factors in clinical practice and describe ways that a large and complex body of knowledge can be applied to individual patients.

Inherited, familial and sporadic primary open-angle glaucoma

The U.S. surgeon general has recently launched a campaign to promote the awareness of the medical value of family history. Further attention should be paid to familial aggregation. Accordingly, we suggest that primary open-angle glaucoma (POAG) be classified into inherited, familial and sporadic categories. The three classes of POAG differ not only in inheritance pattern and familial aggregation but also in methodology and outcome of gene mapping. Inherited POAG follows Mendelian inheritance and has been linked to seven chromosomal loci to date by linkage analysis. Familial POAG does not show a clear pattern of Mendelian inheritance and is typically studied by sib-pair analysis and family-based association analysis, although the results often require replication in multiple samples. Interestingly, many sporadic POAG cases carry known POAG-causing mutations, suggesting genetic predisposition as well. Based on published data, we estimated that inherited and familial POAG cases may account for approximately 72% of all POAG cases. We further formulated a mathematic model to estimate disease prevalence and mutation frequency taking both ethnic background and familial aggregation into consideration.

CONCLUSION

POAG appears to be mainly caused by genetic predisposition in interaction with other risk factors such as age. The suggested classification of POAG may serve as a useful guide in clinical practice and genetic studies where ethnic background and familial aggregation must be taken into consideration.

The impact of glaucoma coding in a large claims database

PURPOSE

Coding variation and its impact on identified populations is a major concern in database analyses. We assessed potential differences in demographics and healthcare charges among patients with open-angle glaucoma identified through different International Classification of Diseases, Ninth Revision (ICD-9) coding algorithms.

DESIGN

Retrospective database analysis.

METHODS

Three glaucoma cohorts were identified based on hierarchical inclusion of patients with >/=2 glaucoma ICD-9 codes (PharMetrics, Inc, Watertown, Massachusetts, USA, 1998 to 2003). Descriptive statistics and healthcare charges were assessed for each cohort.

RESULTS

The three cohorts included 64,380, 14,705, and 4,225 unique patients each. Although significant differences in age, gender, region, payer type, product type, and medical comorbidities existed among the three cohorts, these differences had little impact on resource consumption when the cohorts were combined, given the smaller number of patients outside of the primary cohort.

CONCLUSIONS

Glaucoma coding variation in administrative data sets has limited impact on analyses of resource consumption among open-angle glaucoma patients.

Myocilin Gly252Arg mutation and glaucoma of intermediate severity in Caucasian individuals

OBJECTIVE

To determine the phenotype of an Australian pedigree with the myocilin (MYOC) Gly252Arg mutation, comparing it with other pedigrees carrying the same mutation.

METHODS

All recruited subjects underwent a comprehensive clinical examination, including optic disc assessment, applanation tonometry, and visual field measurement. Mutation analysis was performed through direct sequencing. Haplotype analysis was performed using microsatellite markers around the MYOC gene.

RESULTS

Eight Gly252Arg mutation carriers with glaucoma were identified from the same pedigree. Carriers' mean +/- SD age at diagnosis was 46.3 +/- 11.4 years (range, 31-60 years). Highest recorded intraocular pressure ranged from 27 to 42 mm Hg (mean +/- SD, 32.4 +/- 5.6 mm Hg). Cup-disc ratios in the worst eye ranged from 0.6 to 0.9. Six of the 8 individuals had undergone filtration surgery. A common founding haplotype between MY5 and D1S218 was found for Caucasian individuals tested with this mutation. One subject was compound heterozygotic for the MYOC Gly252Arg mutation and a novel MYOC Gly244Val variant.

CONCLUSIONS

Although a common founder for Gly252Arg across Caucasian subjects was found, the phenotype from this Australian MYOC mutation-carrying pedigree is less severe than previously described. The severity of glaucoma caused by the Gly252Arg mutation may be similar to the Thr377Met MYOC mutation, yet is more severe than the most common Gln368Stop mutation.

CLINICAL RELEVANCE

Since its implication in glaucoma, much work has been performed investigating the clinical features of MYOC-related glaucoma. Given the strong genotype-phenotype correlations with MYOC disease-causing variants, health care professionals armed with such molecular information are able to accurately counsel patients on their likely disease course. Our work suggests that the disease associated with MYOC Gly252Arg is less severe than previously described in other pedigrees with this specific mutation.

Measurement of anterior lens growth after acute primary angle-closure glaucoma

BACKGROUND

To develop Canadian guidelines for the management of primary open-angle glaucoma and provide a quick and practical reference for physicians in the office setting.

METHODS

A Canadian Glaucoma Strategy began with a review of the literature and existing guidelines, as well as consultation with glaucoma specialists and general ophthalmologists across Canada. The resulting information was assessed by a panel of glaucoma experts and general ophthalmologists at the Canadian Glaucoma Strategy Forum to distill what was learned and construct the algorithms of care.

RESULTS

A Canadian Glaucoma Strategy was developed in 4 algorithms. First, patients are diagnosed on the basis of risk assessment and clinical findings. The staging algorithm is designed to determine the disease stage, while the treatment and follow-up algorithms focus on control of intraocular pressure and continuing patient follow-up.

INTERPRETATION

A Canadian Glaucoma Strategy is a practical series of algorithms that can be at hand in the office setting, providing the general ophthalmologist with an up-to-date guide for the management of patients with glaucoma concerns.

Prevalence and Clinical Characteristics of Glaucoma in Adult Chinese: A Population-Based Study in Liwan District, Guangzhou

PURPOSE

To assess the prevalence and mechanism of glaucoma in adults living in an urban area of southern China.

METHODS

Random clustering sampling was used to identify adults aged 50 years and over in Liwan District, Guangzhou. Glaucoma was diagnosed with the ISGEO (International Society of Geographical and Epidemiological Ophthalmology) classification scheme. All subjects underwent gonioscopy.

RESULTS

In the study, 1504 subjects (75.3% participation rate) were examined, with a crude prevalence of all glaucoma of 3.8% (95% confidence interval [CI], 2.8%-4.8%). Primary open-angle glaucoma (POAG) was found in 2.1% (95% CI, 1.4%-2.8%) and primary angle-closure glaucoma (PACG) in 1.5% (95% CI, 0.8%-2.1%). The prevalence of all glaucoma was significantly higher in older people and men.

CONCLUSIONS

POAG was more common than PACG in this southern Chinese population, with rates similar to those reported in Chinese Singaporeans. The age-adjusted rate of POAG was similar to that found in European-derived populations, but PACG was more common among Chinese, indicating that there is a large burden of glaucoma in the Chinese people.

Diagnostic Capability of Optical Coherence Tomography in Evaluating the Degree of Glaucomatous Retinal Nerve Fiber Damage

PURPOSE

To evaluate the role and ability of optical coherence tomography (OCT) to detect differences in peripapillary retinal nerve fiber layer (RNFL) thickness between normal and glaucomatous eyes and also between different severities of glaucoma.

METHOD

This cross-sectional observational study included 160 eyes of 160 healthy subjects and 134 eyes of 134 patients with primary open-angle glaucoma (POAG). Peripapillary RNFL thickness was measured on OCT using the fast RNFL thickness protocol. The RNFL thickness parameters used for evaluation included average RNFL thickness and inferior, superior, nasal, and temporal RNFL thickness. The glaucomatous eyes were subdivided into three subgroups on the basis of visual field defects and a fourth subgroup of eyes blinded by glaucoma. RNFL thickness parameters were compared among the normal eyes and the glaucoma subgroups. Correlation of global visual field indices with RNFL thickness parameters was also performed.

RESULTS

The average RNFL in control subjects, early glaucoma, moderate glaucoma, severe glaucoma, and blind glaucoma were 102.30 +/- 10.34, 77.68 +/- 15.7, 66.07 +/- 15.5, 53.65 +/- 14.2, and 44.93 +/- 4.95 microm, respectively. There was a significant difference in all RNFL thickness parameters between normal and all glaucoma subgroups (P < 0.001). Average and inferior RNFL thicknesses showed the highest area under the receiver operating characteristic curve, with 0.905 and 0.862 for normal versus early glaucoma, 0.705 and 0.722 for early versus moderate glaucoma, 0.737 and 0.717 for moderate versus severe glaucoma, and 0.635 and 0.584 for severe versus blind glaucoma. Both mean deviation (MD) and corrected pattern standard deviation (CPSD) showed a significant correlation with all the RNFL thickness parameters in eyes with glaucoma (P < 0.001).

CONCLUSIONS

RNFL thickness measured on OCT may serve as useful adjuncts in accurately and more objectively distinguishing normal from glaucomatous eyes, even in the early stages of glaucoma and may help to differentiate various severities of glaucoma. Average and inferior RNFL thicknesses are among the most efficient parameters for distinguishing such a differentiation. RNFL thicknesses in eyes blinded by glaucoma provide an estimate of the component of the RNFL thickness, which is not related to visual function.

Correlation Between Intraocular Pressure, Central Corneal Thickness, Stage of Glaucoma, and Demographic Patient Data

PURPOSE

To determine the correlation of central corneal thickness (CCT) to Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT, PASCAL), and to glaucoma stage as assessed by cup-to-disc ratio (CDR).

DESIGN

Prospective, cross-sectional tricenter observation study.

PATIENTS AND METHODS

From three glaucoma specialty practices a sample of 406 independent eyes was included. After ultrasound pachymetry, intraocular pressure was measured using PASCAL and Goldmann applanation tonometry and cup-to-disc ration was reassessed. Demographic data were included in the multivariate analysis.

RESULTS

Mean corneal thickness was 540 microm. African Americans and normal-tension glaucoma patients showed the lowest values (518 microm and 522 microm, respectively). These values were significantly thinner than the central corneal thickness of Caucasians (549 microm) and ocular hypertensives (564 microm). Intraocular pressure assessed by Goldmann applanation tonometry shows a significant correlation with central corneal thickness (r = 0.068, P < 0.001), whereas PASCAL is not significantly associated with central corneal thickness (r < 0.001, P = 0.997). Increased IOP is significantly correlated with large ocular pulse amplitudes (r = 0.13, P < 0.001), which is predominantly seen in ocular hypertensives. A significant negative correlation was detected between cup-to-disc ratio and central corneal thickness (r = 0.102, P < 0.001).

CONCLUSION

Glaucoma patients with thin central corneal thickness are more likely to be found at an advanced stage of the disease and among those with normal-tension glaucoma and black African ancestry. Underestimation of intraocular pressure by Goldmann applanation tonometry could be one causative factor.

Enhanced Glaucoma Staging System (GSS 2) for classifying functional damage in glaucoma

PURPOSE

To introduce a new method, derived from the Glaucoma Staging System (GSS), for classifying glaucomatous visual field defects.

PATIENTS AND METHODS

Four sample groups composed respectively of 471 (sample #1), 128 (sample #2), 185 (sample #3), and 131 (sample #4) patients with either ocular hypertension or chronic glaucoma were considered. The GSS 2 uses both the MD and CPSD/CLV or PSD/LV perimetric indices to classify visual field defect in 6 stages and in 3 types (generalized, localized, and mixed). The formulas were determined using sample #1. A new borderline stage was created, on the basis of sample #2. The relationship between the PSD/LV and CPSD/CLV values was studied on sample #3 to verify the possibility of using the uncorrected indices instead of the CPSD/CLV. The relationship with other classification methods was studied on sample #4.

RESULTS

The GSS 2 showed a strong level of association with the AGIS and the Hodapp-Parrish-Anderson methods in staging defect severity. A good correlation was also found with a classification based on the Bebie curve.

CONCLUSIONS

The GSS 2 was able to correctly classify both damage severity and perimetric defect type in the sample studied, using either the corrected or uncorrected visual field indices. It is a quick and easy method, and its formulas can be introduced in any software.

Coding of glaucoma for patients with uveitis in the medicare database

PURPOSE

To investigate possible causes for, and implications of, variations in coding of glaucoma for patients with uveitis in the Medicare database.

PATIENTS AND METHODS

We identified 6,391 patients coded with one of several ICD-9 codes designating a form of uveitis from a 5% sample of the 1999 Medicare database. The proportion of patients with uveitis codes who also had codes for uveitic glaucoma, primary open-angle glaucoma (POAG), or unspecified open-angle glaucoma (OAG) were determined. The proportion with codes for argon laser trabeculoplasty (ALT), trabeculectomy, visual field examinations, fundus photographs, and gonioscopy were calculated in three groups: patients with both uveitis and uveitic glaucoma; those with both uveitis and POAG; and those with both uveitis and unspecified open-angle glaucoma. Summaries of the total allowed reimbursement related to eye visits and to eye codes were determined.

RESULTS

Of the 6,391 patients with uveitis who were studied, 1,260 (19.7%) also had the code for POAG; 412 (6.4%) had the code for OAG; and 117 (1.8%) had the code for uveitic glaucoma. Visual field testing was less common among patients with uveitic glaucoma (37%) than among those with POAG/uveitis (46%) or OAG/uveitis (44%) (P < 0.001). There were no statistically significant differences among the three groups in the amount of total reimbursement related to eye services or eye codes.

CONCLUSIONS

The code for POAG appears to be used in lieu of uveitic glaucoma in many cases. Discrepancies are probably not influenced by expected reimbursements, as much as by a lack of understanding about the available ICD-9 codes.

Categorizing the stage of glaucoma from pre-diagnosis to end-stage disease

PURPOSE

To provide a reliable, comprehensive staging system to assess glaucoma stage in the absence of an universally accepted glaucoma staging system (GSS) on the basis of visual field results.

DESIGN

Literature review and GSS adaptation.

METHODS

After a review of published GSSs was conducted, the Bascom Palmer (Hodapp-Anderson-Parrish) GSS was selected as an appropriate platform for a retrospective GSS on the basis of visual fields. The system was modified by a panel of glaucoma specialists, and additional modifications were made after pilot testing to cover the full range of disease progression, from preglaucoma diagnosis to complete blindness; the ordered stages reflect the typical progression of glaucoma.

RESULTS

The GSS is comprised of six ordered stages and is on the basis of the Humphrey visual field. The completed GSS was validated by reviewing patient charts from 12 US glaucoma centers.

CONCLUSIONS

The GSS allows accurate staging of 100% of glaucoma on the basis of visual fields and other data, enabling evaluation of disease progression and resource utilization at various glaucoma stages. Additionally, treatment costs may be assigned to determine cost-effectiveness of treatment. Research utilizing the GSS has found that cost of care increases with increasing disease severity. The GSS may be used as the basis for creating treatment guidelines, which have the potential to delay glaucoma progression and lower treatment costs.

Development and comparison of automated classifiers for glaucoma diagnosis using Stratus optical coherence tomography

PURPOSE

To develop and compare the ability of several automated classifiers to differentiate between normal and glaucomatous eyes based on the quantitative assessment of summary data reports from Stratus optical coherence tomography (OCT; Carl Zeiss Meditec Inc., Dublin, CA) in a Chinese population in Taiwan.

METHODS

One randomly selected eye from each of 89 patients with glaucoma and each of 100 age- and sex-matched normal individuals were included in the study. Measurements of glaucoma variables (retinal nerve fiber layer thickness and optic nerve head analysis results) were obtained by Stratus OCT. With the Stratus OCT parameters used as input, receiver operative characteristic (ROC) curves were generated by three methods, to classify eyes as either glaucomatous or normal: linear discriminant analysis (LDA), Mahalanobis distance (MD), and artificial neural network (ANN). The area under the ROC curve was optimized by principal component analysis (PCA). Classification accuracy was determined by cross validation.

RESULTS

The average visual field mean deviation was -0.7 +/- 0.6 dB in the normal group and -2.7 +/- 1.9 dB in the glaucoma group. The areas under the ROC curves were 0.824 (LDA), 0.849 (MD), 0.821 (ANN), 0.915 (LDA with PCA), 0.991 (MD with PCA), and 0.874 (ANN with PCA).

CONCLUSIONS

With Stratus OCT parameters used as input, automated classifiers show promise for discriminating between glaucomatous and normal eyes. MD measured from multivariate data can predict the severity of glaucoma through the construction of a measurement space. After PCA, implementation results show that the Mahalanobis space created by MD surpasses LDA and ANN in diagnosing glaucoma.

Optical coherence tomography machine learning classifiers for glaucoma detection: a preliminary study

PURPOSE

Machine-learning classifiers are trained computerized systems with the ability to detect the relationship between multiple input parameters and a diagnosis. The present study investigated whether the use of machine-learning classifiers improves optical coherence tomography (OCT) glaucoma detection.

METHODS

Forty-seven patients with glaucoma (47 eyes) and 42 healthy subjects (42 eyes) were included in this cross-sectional study. Of the glaucoma patients, 27 had early disease (visual field mean deviation [MD] > or = -6 dB) and 20 had advanced glaucoma (MD < -6 dB). Machine-learning classifiers were trained to discriminate between glaucomatous and healthy eyes using parameters derived from OCT output. The classifiers were trained with all 38 parameters as well as with only 8 parameters that correlated best with the visual field MD. Five classifiers were tested: linear discriminant analysis, support vector machine, recursive partitioning and regression tree, generalized linear model, and generalized additive model. For the last two classifiers, a backward feature selection was used to find the minimal number of parameters that resulted in the best and most simple prediction. The cross-validated receiver operating characteristic (ROC) curve and accuracies were calculated.

RESULTS

The largest area under the ROC curve (AROC) for glaucoma detection was achieved with the support vector machine using eight parameters (0.981). The sensitivity at 80% and 95% specificity was 97.9% and 92.5%, respectively. This classifier also performed best when judged by cross-validated accuracy (0.966). The best classification between early glaucoma and advanced glaucoma was obtained with the generalized additive model using only three parameters (AROC = 0.854).

CONCLUSIONS

Automated machine classifiers of OCT data might be useful for enhancing the utility of this technology for detecting glaucomatous abnormality.

[Ocular structural and functional disturbances, typical for open-angle glaucoma, are the basis for the development of its present-day classification]

A major breakthrough in the development of clinical studies of the structures and functions of the optic disk (OD) has allowed one to notice the earliest manifestations of open-angle glaucoma (OAG). Along with this, consideration of the data accumulated in the literature on the role of risk factors of glaucoma and on the variants of the clinical course of the disease has enabled the author to suggest to update the OAG classification developed 30 years ago. The proposed schemes use just the procedures currently recommended by the International Glaucoma Association as the most informative ones.

Patterns of glaucomatous visual field progression identified by three progression criteria

PURPOSE

To determine typical patterns of repeatable glaucomatous visual field progression.

DESIGN

Retrospective analysis of data obtained from two prospective studies.

METHODS

Included were 72 eyes of 72 patients tested up to six times over 2 years, and 40 eyes of 40 patients followed annually for up to 12 years. Each patient had two abnormal baseline visual fields, abnormal optic nerves, and serial fields. Progression was identified using three methods: by glaucoma change probability using total deviation (GCP-TD) and pattern deviation (GCP-PD) plots and by a clinical criteria. Progression was categorized as deepening or expansion of an existing scotoma, or a new scotoma.

RESULTS

The percentage of eyes repeatably progressed ranged from 17% to 27%. The most common pattern of progression was a deepening of an existing scotoma in the annual group, followed by expansion. With two follow-ups required, percentages for deepening only were 20% (clinical classifier). A combination of expansion and deepening was most common for the GCP criteria: 15% (GCP-TD classifier), and 10% (GCP-PD classifier) for the annual group. For the semiannual group, deepening was most common with the clinical criteria (11% of eyes), and deepening with expansion was most common by GCP criteria (14%, GCP-TD and GCP-PD). No eyes showed repeatable new scotomas.

CONCLUSIONS

Glaucomatous visual fields progress in the area of the visual field where baseline testing showed an existing scotoma. Follow-up testing might be improved by concentrating on already defective locations and using sparser test patterns or screening algorithms in normal areas of the visual field.

Genetics and bioinformatics of primary open angle glaucoma: an Indian perspective

Glaucoma is the second largest blinding disorder, after cataract, affecting about 67 million people worldwide. In India about 1.5 million people are blind due to glaucoma. Primary open angle glaucoma is the major sub-type of glaucoma affecting all ages and is genetically complex. Myocilin and optineurin are two different genes that have been implicated for primary open angle glaucoma. This review is focused on the studies being conducted in India on primary open angle glaucoma to identify the molecular defects and new directions undertaken using bioinformatic approaches towards a better understanding of the disease.

Relationship between Indices of Humphrey Perimetry and Frequency Doubling Technology Perimetry in Glaucoma

PURPOSE

To study whether the correlation between indices of Humphrey perimetry and Frequency Doubling Technology (FDT) perimetry differs in the early and later stages of glaucoma.

METHODS

This study included 200 eyes of 200 patients with primary open-angle glaucoma or normal-tension glaucoma. The eyes were classified into the early and later stages by the median value (-4.51 dB) (Classification 1; n = 100 and 100, respectively) or the average value of the maximum and minimum values (-11.90 dB) (Classification 2; n = 165 and 35, respectively) of mean deviation (MD) obtained from a set of measurements with the Humphrey Full-Threshold 30-2 program in all eyes. The correlation between MD (H-MD) or pattern standard deviation (PSD) (H-PSD), as obtained from another set of measurements with the Humphrey Full-Threshold 30-2 program, and MD (F-MD) or PSD (F-PSD), as calculated by the Full-Threshold N-30 program of FDT perimetry, were evaluated using linear regression analysis.

RESULTS

Overall, H-MD and H-PSD significantly correlated with F-MD (r = 0.713; P < 0.001) and F-PSD (r = 0.731; P < 0.001), respectively. In each of Classifications 1 and 2, H-MD and H-PSD significantly correlated with F-MD and F-PSD, respectively, both in the early and later stages. However, in each classification, the correlation between H-MD and F-MD differed significantly between the two stages (Classification 1; P < 0.001; Classification 2, P = 0.003), while the correlation between H-PSD and F-PSD did not differ significantly between the two stages.

CONCLUSION

The degree of correlation between H-MD and F-MD differed between the early and later stages of glaucoma.

Korrelation zwischen der konfokalen Tomographie des Nervus opticus (HRT) und der perimetrischen Frequenzverdoppelungstechnik (FDT)

PURPOSE AND METHODS

To correlate the five phases of optic nerve (ON) damage staging, as assessed by means of confocal tomography (HRT) with the five stages of visual field, assessed by conventional perimetry (standard automatic perimetry, SAP) and classified in five stages according to the "GLAUCOMA STAGING SYSTEM". The second step was to correlate the same optic nerve staging system with the results of the visual field tested with non-conventional perimetry using the frequency doubling technology (FDT) employing the Humphrey-Zeiss and Welch-Allyn perimeter. The five stages of FDT visual field data evolution were classified according to the new "FDT STAGING SYSTEM".

MATERIAL

58 visual fields of 58 consecutive selected patients with either ocular hypertension or glaucoma with an age-range between 15 and 65 years.

METHOD

Visual field examination was performed with conventional (Octopus G2 threshold test) and non-conventional perimetry (FDT N30 threshold test), and the ON was assessed with confocal tomography (Heidelberg Retina Tomograph).

RESULTS

In 40 % of the visual fields tested normal with conventional perimetry, non-conventional perimetry (FDT) detected glaucomatous visual field defects corresponding topographically with the optic nerve damage revealed by HRT.

CONCLUSIONS

New non-conventional perimetric techniques such as FDT enable the very early detection of visual field defects topographically correlated to optic nerve damage.

[In-vivo measurement of autofluorescence in the parapapillary atrophic zone of optic discs with and without glaucomatous atrophy]

BACKGROUND

To assess the level of autofluorescence (lipofuscin) of atrophic parapapillary zones in different stages of glaucomatous optic disc atrophy.

METHODS

Controlled cross-sectional prospective analysis of 79 consecutive eyes (15 normals as controls, 26 with ocular hypertension, 38 with primary open angle glaucoma). Eyes with retinal diseases or retinal pigment epithelial pathologies were excluded. The confocal scanning laser ophthalmoscope (HRA, Heidelberg Retina Angiograph) was used after lipofuscin excitation with argon blue laser (488 nm) to detect parapapillary autofluorescence in a spectrum above 500 nm. Size, extension of the parapapillary autofluorescent area and its mean distance to the optic nerve head were measured using the HRA standard software. Additional optic nerve head photographs taken with the 15 degrees Zeiss telecentric fundus camera (30 degrees camera with 2 x magnifier) were examined by two experienced ophthalmologists to determine the stage of glaucomatous optic disc atrophy (stages 0 to 4).

RESULTS

Very small autofluorescent areas were found in vital discs (optic nerve glaucoma stage 0) in the parapapillary atrophic area (0.08 +/- 0.12 mm (2)) in contrast to glaucomatous discs in stage 1 (0.24 +/- 0.26 mm (2)) and stages 2, 3 and 4 (0.59 +/- 1.29 mm (2), logistic regression analysis r = 0.71; P = 0.029). The circular extension of the autofluorescent area correlated borderlined with the stage of the glaucomatous disc atrophy (higher glaucoma stages: r = 0.82; P = 0.09). The autofluorescent area was larger in OHT than in controls (0.11 mm (2) vs. 0.04 mm (2), P < 0.03). The circular extension of the autofluorescent area was longer in OHT than in controls (0.5 mm vs. 1.15 mm, P < 0.04).

CONCLUSIONS

As a sign of pronounced lipofuscin accumulation in the parapapillary atrophic zone higher degrees of fundus autofluorescence can be detected in OHT and manifest primary open angle glaucoma in contrast to normals. The lipofuscin accumulation is correlated with the stage of progression of glaucoma and the stage of optic disc atrophy. The detection of active parapapillary autofluorescent areas especially in OHT may offer the ophthalmologist an important tool for early diagnosis.

Sequential classification in glaucoma diagnosis

BACKGROUND

Large-scale screening in glaucoma diagnosis is expensive and time consuming. Sequential classification strategies can provide an effective combination of time-efficiency and diagnostic accuracy for glaucoma screening.

METHODS

In a cross-sectional clinical study, a sequential diagnostic strategy, based on several psychophysical and electrophysiological tests, was evaluated on measurements from 595 eyes from 310 patients with primary open-angle glaucoma, and 419 eyes from 213 control subjects (age range 18-70 years in each group). Patients and controls successively underwent up to five psychophysical and electrophysiological diagnostic tests. Optic disc morphometry was taken as gold standard. Adapting group sequential techniques, sensitivity and specificity for the whole diagnostic program were controlled, allotting overall error rates of 10%. The criteria for the diagnostic process were developed in a learning sample (677 eyes) and verified in a validation sample (337 eyes).

RESULTS

In the validation sample, 62.0% of the examined eyes could be classified, using a sequential 15-min two-step program. An overall 13.6% "gain" of saved time, compared to non-sequential discriminant analysis, was achieved without loss of diagnostic accuracy. A sequential 45-min five-step program classified 68.8% of the whole sample before morphometry, saving approximately 39% of examination time, compared to taking the complete discriminant score.

CONCLUSION

Especially in screening, where the use of time-consuming and complicated diagnostic procedures is restricted, the implementation of testing programs based on group sequential strategies might be a promising means of saving personnel resources and reducing inconvenience for patients.

Syndroma: glaucoma pigmentatum primarium--pigmented glaucoma

In this study pigmented glaucoma was diagnosed in 29 out of 4350 patients suffering from glaucoma. In clinical analysis of those cases main attention was put on Krukenberg spindle with emphasis on the process and reason of its development. In all cases of Krukenberg spindle moderate myopia and myopic astigmatism were present. The main axis of the spindle lies in the principal meridian of corneal astigmatism. The principal meridian of the anterior cornea surface corresponds with the axis of the principal meridian of the posterior corneal surface. The higher degree of astigmatism more pronounced Krukenberg spindle. This corresponds to a number of cases in which the spindle is hardly recognisable in the astigmatism, of only +/- 0.25 to +/- 0.50 Dcyl. The axis of meridian corresponds to direct astigmatism (from 110 degrees to 70 degrees). The authors conclude that there is no pigmented Krukenberg spindle without myopic astigmatism. It is for this reason and because of the inheritance factor that this type of glaucoma should be considered primary glaucoma and a separate clinical entity.

Is open-angle glaucoma associated with early menopause? The Rotterdam Study

The authors examined the association between age at menopause and open-angle glaucoma among women aged > or = 55 years in the population-based Rotterdam Study (1990--1993). Information on age and type of menopause was obtained by interview. Subjects (n = 3,078) were stratified into three categories according to age at menopause: <45 years, 45--49 years, and > or = 50 years, with the last group serving as the reference group. Diagnosis of open-angle glaucoma was based on the presence of a glaucomatous visual field defect and glaucomatous optic neuropathy. Open-angle glaucoma was diagnosed in 78 women with a natural menopause and 15 women with an artificial menopause. In the category of natural menopause, women who went through menopause before reaching the age of 45 years had a higher risk of open-angle glaucoma than the reference group (odds ratio = 2.6; 95% confidence interval: 1.5, 4.8), after adjustment for age and use of hormone replacement therapy. Among women who went through menopause between the ages of 45 and 49 years, the odds ratio was 1.1 (95% confidence interval: 0.7, 2.0). These findings suggest that early menopause is associated with a higher risk of open-angle glaucoma.

Comparative study of retinal nerve fiber layer loss in normal-tension glaucoma and chronic open-angle glaucoma

PURPOSE

To clarify whether loss of the retinal nerve fiber layer in normal-tension glaucoma (NTG) differs from that in chronic open-angle glaucoma (COAG).

METHODS

Using a scanning laser polarimeter, retinal nerve fiber layer thickness (RNFLT) was measured in 21 patients with NTG, 21 patients with COAG and 21 normal controls. The three groups were matched for age, and the NTG and COAG groups were matched for visual field loss.

RESULTS

The mean RNFLT was significantly less in the NTG than in the control group and less in the COAG than in the controls and NTG group. Although the correlations between the parameters of RNFLT and homotopic visual field measurements were significant in COAG, none of the correlations were significant in NTG.

CONCLUSIONS

The present results suggest that loss of the retinal nerve fiber layer in NTG differs from that in COAG.

Transforming growth factor beta 2 levels in the aqueous humor in different types of glaucoma and the relation to filtering bleb development

PURPOSE

To investigate the transforming growth factor beta 2 (TGF-beta 2) levels and total protein levels in the aqueous humor of eyes with different types of glaucoma [primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PSX), juvenile glaucoma (JG)], and the relation to filtering bleb development after trabeculectomy.

METHODS

Aqueous humor was collected at the beginning of surgery from 52 eyes with glaucoma (29 POAG eyes, 17 PSX eyes, 6 JG eyes) and from 29 control eyes that underwent cataract operation. TGF-beta 2 levels (intrinsically activated and total TGF-beta 2) using ELISA methods as well as total protein concentrations of the aqueous humor were determined. All preoperative clinical data of the glaucoma eyes (age, gender, IOP, previous treatment, type of surgery) were compared with the TGF-beta 2 levels. In 40 of these eyes, the postoperative follow-up (filtering bleb development, need for intervention, IOP) was correlated to the preoperatively determined TGF-beta 2 levels.

RESULTS

TGF-beta 2 levels were increased in nearly half of the eyes with POAG and in most of the eyes with JG, but in eyes with PSX, TGF-beta 2 levels were within the normal range. No correlation between TGF-beta 2 levels and age, gender, IOP, previous treatment, or type of surgery, or between TGF-beta 2 levels and protein levels in aqueous humor, was found. Correlation between bleb formation and TGF-beta 2 levels revealed that all but two of the POAG eyes with good clinical outcome (type 1 bleb) had normal levels of activated TGF-beta 2. Of the 13 eyes that needed postoperative intervention (type 2 and type 3 bleb), 8 had high and 5 had normal TGF-beta 2 levels.

CONCLUSIONS

PSX eyes differ from POAG and JG eyes not only by their clinical or biomicroscopic appearance, but also by their normal TGF-beta 2 levels in aqueous humor. The fact that most of the POAG eyes with favorable bleb development had normal TGF-beta 2 levels indicated that there might be some relationship between bleb formation and TGF-beta 2 levels. On the other hand, the fact that eyes with less favorable bleb development had both low and high TGF-beta 2 levels indicated that other factors are also involved in the scarring of the filtration bleb.

Evaluation of the Brusini glaucoma staging system for typing and staging of perimetric results

BACKGROUND

Brusini's recently introduced glaucoma staging system (GSS) categorizes visual-field damages into different types (i.e. generalized, mixed and localized) and classifies them into stages similar to those of Aulhorn-Karmeyer. Basically, the Brusini GSS is a scatterplot of mean defect (x-axis) and corrected loss variance (CLV; y-axis). The Brusini GSS charts are claimed to be simple to understand due to their 2-dimensional spatial representation and there is no subjective interpretation necessary, since their numerical presentation provides an objective evaluation. Inter- and intraindividual comparisons are, thus, provided 'at a glance'.

METHODS

Retrospectively, 610 visual fields (Octopus 201, Program G1) for each eye of 32 glaucoma patients were inspected on screen with PeriData 7.0. The performance of the Brusini GSS was evaluated in terms of typing of visual-field defect and staging as defined by the Aulhorn-Karmeyer classification.

RESULTS

Typing of defects into 'normal' and various degrees of generalized and localized damage agreed with PeriData in 89% of fields; 5% were wrongly classified as normal by the Brusini GSS. The type of visual defect showed in 1.3% fields as marked and in 5% a minor discrepancy. Most of the 11% of nonagreement was due to high short-term fluctuation. Agreement could potentially be enhanced by using loss variance instead of CLV Staging of visual-field defects with Brusini GSS charts was in agreement with the Aulhorn-Karmeyer classification in 73% of fields.

CONCLUSION

The authors recommend the Brusini GSS because of its simplicity to concisely describe visual-field damage for clinical use as well as research work and because of the remarkably good agreement with the well-known Aulhorn-Karmeyer classification.

Changing views on open-angle glaucoma: definitions and prevalences--The Rotterdam Study

PURPOSE

To create a quantitative basis for diagnostic criteria for open-angle glaucoma (OAG), to propose an epidemiologic definition for OAG based on these, and to determine the prevalence of OAG in a general white population.

METHODS

Of the 7983 subjects 55 years of age or older participating in the population-based Rotterdam Study, 6756 subjects participated in the ophthalmic part of this study (6281 subjects living independently and 475 in nursing homes). The criteria for the diagnosis of OAG were based on ophthalmoscopic and semiautomated Imagenet estimations of the optic disc such as vertical cup-to-disc ratio (VCDR), minimal width of neural rim, or asymmetry in VCDR between both eyes, and visual field testing with kinetic Goldmann perimetry. All criteria for the diagnosis of OAG were assessed in a masked way independently of each other.

RESULTS

Mean VCDR on ophthalmoscopy was 0.3 and with Imagenet 0.49, and the 97.5th percentile for both was 0.7. The prevalence of glaucomatous visual field defects was 1.5%. Overall prevalence of definite OAG in the independently living subjects was 0.8% (95% confidence interval [CI] 0.6, 1.0; 50 cases). Prevalence of OAG in men was double that in women (odds ratio 2.1; 95% CI 1.2, 3.6). Different commonly used criteria for diagnosis of OAG resulted in prevalence figures ranging from 0.1% to 1.2%.

CONCLUSIONS

The overall prevalence of OAG in the present study was comparable to most population-based studies. However, prevalence figures differed by a factor of 12 when their criteria for OAG were applied to this population. A definition for definite OAG is proposed: a glaucomatous optic neuropathy in eyes with open angles in the absence of history or signs of secondary glaucoma characterized by glaucomatous changes based on the 97.5 percentile for this population together with glaucomatous visual field loss. In the absence of the latter or of a visual field test, it is proposed to speak of probable OAG based on the 99.5th or possible OAG based on the 97.5th percentiles of glaucomatous disc changes for a population under study.

Open-angle glaucoma in an urban population in southern India: the Andhra Pradesh eye disease study

OBJECTIVE

To assess the prevalence and features of open-angle glaucoma in an urban population in southern India.

DESIGN

A population-based cross-sectional study.

PARTICIPANTS

A total of 2522 persons (85.4% of those eligible) of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.

TESTING

The participants underwent an interview and detailed eye examination that included logarithm of minimum angle of resolution visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, dilatation, cataract grading, and stereoscopic fundus evaluation. Automated Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) and optic disc photography were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more.

MAIN OUTCOME MEASURES

Definite primary open-angle glaucoma (POAG) was defined as obvious glaucomatous optic disc damage and visual field loss in the presence of an open-angle, and suspected POAG was defined as suspected glaucomatous optic disc damage without definite visual field loss. Ocular hypertension (OHT) was defined as IOP of 22 mmHg or more without glaucomatous optic disc damage or visual field loss in the presence of an open-angle. Glaucomatous optic disc damage or IOP of 22 mmHg or more secondary to an obvious cause and with an open-angle was defined as secondary open-angle glaucoma.

RESULTS

Definite POAG, suspected POAG, and OHT were present in 27, 14, and 7 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval) of 1.62% (0.77%-2.48%), 0.79% (0.39%-1.41%), and 0.32% (0.10%-0.78%) in those 30 years of age or older, and 2.56% (1.22%-3.91%), 1.11% (0.43%-1.78%), and 0.42% (0.11%-1.12%) in those 40 years of age or older, respectively. The prevalence of POAG increased significantly with age using multivariate analysis (P < 0.001). Only two of 27 participants (7.4%) with definite POAG had been previously diagnosed and treated, and 66.7% of the previously undiagnosed had IOP less than 22 mmHg. Fourteen of 27 participants (51.9%) with definite POAG had severe glaucomatous damage based on optic disc and visual field criteria, of which five participants (18.5%) had at least one blind eye as a result of POAG (all with best-corrected distance visual acuity less than 20/400 or central visual field less than 10 degrees); the other 13 participants (48.1%) had moderate glaucomatous damage. Because visual fields and optic disc photography were not performed on all participants, the prevalence of POAG may have been underestimated. Secondary open-angle glaucoma was present in one participant as a result of angle recession.

CONCLUSIONS

The prevalence of open-angle glaucoma in this urban population in southern India is at least as much as that reported recently from white populations in developed countries. However, the vast majority of persons with glaucoma were undiagnosed in this population, and a large proportion of those having definite POAG already had severe glaucomatous damage.

Comparative study of retinal nerve fiber layer damage in Japanese patients with normal- and high-tension glaucoma

PURPOSE

To look for possible differences in the pattern of retinal nerve fiber layer (RNFL) damage induced by normal- and high-tension glaucoma.

METHODS

The study included randomly selected eyes from 27 patients with open-angle, high-tension glaucoma (mean age, 54.7 +/- 15.0 years; range 21-74 years) and from 19 age-matched patients with normal-tension glaucoma (mean age, 55.7 +/- 11.9 years; range 35-83 years). Eyes were examined using scanning laser polarimetry.

RESULTS

The ratio between the superior and inferior quadrant thickness, or symmetry, was significantly lower in patients with high-tension glaucoma (1.00 +/- 0.22) than in patients with normal-tension glaucoma (1.18 +/- 0.32). Similarly, the ratio of the superior to the nasal quadrant thickness was significantly lower in patients with high-tension glaucoma (1.56 +/- 0.38) than in patients with normal-tension glaucoma (1.80 +/- 0.29). No statistically significant differences in the other parameters were detected between the two groups.

CONCLUSION

These results show that the pattern of RNFL change is different in patients with high- and low-tension glaucoma. The thickness of the RNFL is reduced symmetrically in the superior and inferior quadrants in high-tension glaucoma, whereas a more localized defect on the inferior RNFL occurs in normal-tension glaucoma.

Influence of myopic disc shape on the diagnostic precision of the Heidelberg Retina Tomograph

PURPOSE

To investigate the diagnostic capability of a glaucoma diagnostic classification program for the Heidelberg Retina Tomograph (HRT) in eyes with myopic disc shapes.

METHODS

Sixty-six normal subjects (66 eyes) and 78 open-angle glaucoma patients (78 eyes) were enrolled. The eyes were divided into two groups; those eyes with myopic and those with nonmyopic disc shapes. The classification was based on clinical judgment made after the examination of stereophotographs of the discs without considering the refractive errors. The agreement between the classification program and the clinical diagnosis was evaluated for sensitivity, specificity, and diagnostic precision. The influence of the disc shape on the HRT topographic parameters was evaluated.

RESULTS

The sensitivity, specificity, and diagnostic precision of the HRT were 83%, 95%, and 89% in eyes with nonmyopic disc shapes, but 71%, 96%, and 83% in those with myopic disc shapes. Rim volume, height variation contour, mean retinal fiber nerve layer (RNFL) thickness, and RNFL cross-section area were significantly larger in eyes with myopic disc shapes than in eyes with nonmyopic discs, regardless of the clinical diagnosis.

CONCLUSIONS

The classification program should be modified to take into account the myopic disc shape in order to improve its capability to make more accurate diagnosis of glaucoma possible.

The definition of normal-tension glaucoma

PURPOSE

To evaluate the consistency of the definition of normal-tension glaucoma (NTG).

METHODS

All articles about NTG published between 1973 and 1997 from three clinical journals of ophthalmology were identified by a literature search. They were reviewed to determine criteria used to define NTG, including optic nerve assessment and intraocular pressure (IOP) requirements.

RESULTS

There were 63 articles identified that defined the disease entity NTG, including 30 published between 1973 and 1992 and 33 published between 1993 and 1997. Maximum IOP values acceptable for designation as NTG ranged from 17 mmHg to 26 mmHg. A significantly greater proportion of studies published during the last 5 years required maximum IOP values < or = 21 mmHg. Inclusion criteria based on structural characteristics of the glaucomatous optic disc or on the glaucomatous visual field were present in 55 (87%) and 56 (89%) articles, respectively. Of the seven articles that listed specific features classifying a disc as glaucomatous, seven (100%) were published within the last 5 years. Of the 13 articles that listed specific features classifying a field as glaucomatous, 9 (69%) were published within the last 5 years.

CONCLUSION

The criteria used to define NTG during the last 25 years have been highly variable. However, publications during the last 5 years have been more likely to require a maximum IOP < or = 21 mmHg and to describe specific features of the glaucomatous optic disc and visual field.