Glaucomatous Field Research Articles

Glaucoma Progression Detection: Agreement, Sensitivity, and Specificity of Expert Visual Field Evaluation, Event Analysis, and Trend Analysis

To assess sensitivity, specificity, and agreement among automated event analysis, automated trend analysis, and expert evaluation to detect glaucoma progression. This was a prospective study that included 37 eyes with a follow-up of 36 months. All had glaucomatous disks and fields and performed reliable visual fields every 6 months. Each series of fields was assessed with 3 different methods: subjective assessment by 2 independent teams of glaucoma experts, glaucoma/guided progression analysis (GPA) event analysis, and GPA (visual field index-based) trend analysis. Kappa agreement coefficient between methods and sensitivity and specificity for each method using expert opinion as gold standard were calculated. The incidence of glaucoma progression was 16% to 18% in 3 years but only 3 cases showed progression with all 3 methods. Kappa agreement coefficient was high (k=0.82) between subjective expert assessment and GPA event analysis, and only moderate between these two and GPA trend analysis (k=0.57). Sensitivity and specificity for GPA event and GPA trend analysis were 71% and 96%, and 57% and 93%, respectively. The 3 methods detected similar numbers of progressing cases. The GPA event analysis and expert subjective assessment showed high agreement between them and moderate agreement with GPA trend analysis. In a period of 3 years, both methods of GPA analysis offered high specificity, event analysis showed 83% sensitivity, and trend analysis had a 66% sensitivity.

Patterns of Damage in Chronic Angle-Closure Glaucoma Compared to Primary Open-Angle Glaucoma

To compare patterns of damage in chronic angle-closure glaucoma (CACG) to a control group of patients with primary open-angle glaucoma (POAG). Retrospective cross-sectional study. setting: Academic tertiary-care glaucoma clinic. study population: Thirty-two eyes of 32 patients with CACG and good-quality Heidelberg Retina Tomograph (HRT) images (pixel standard deviation <50 μm) and stereoscopic disc photographs within 1 year of a visual field showing reproducible glaucomatous field loss (mean deviation ≥-15.0 dB) were enrolled. Control eyes with POAG meeting similar criteria and matched for severity of field loss (±1 dB) and race were selected. outcome measures: Presence of focal rim loss (≤1 clock hour), HRT stereometric parameters, and extent and location of field loss. The average mean deviation was -5.1 dB in both groups. Patients with CACG were more hyperopic (0.6 ± 0.4 vs -1.4 ± 0.5 D; P < .001) and had higher IOP at the time of imaging (15.8 ± 0.8 vs 13.9 ± 0.9 mm Hg; P = .015). Focal disc damage was not less frequent in PACG eyes (19% vs 24%; P = .545). Eyes with PACG had smaller cup area, cup volume, and mean cup depth and larger rim/disc area ratio (P < .05 for all), which persisted after adjusting for disc size, age, refractive error, and IOP. The average (±SD) number of abnormal test locations was similar in the 2 groups (P = .709), although CACG eyes were less likely to have paracentral points involved (47% vs 72%; P = .04). Patterns of glaucomatous damage seem to be different in CACG compared with POAG. This difference in patterns of damage may adversely affect detection of early disease or its progression in CACG.

Glaucoma-like optic neuropathy in patients with intracranial tumours

To examine frequency and associated factors of glaucoma-like appearance of the optic nerve head in patients with intrasellar, suprasellar or parasellar tumours. This retrospective clinical observational study included patients who were consecutively treated for intrasellar tumours (n = 143), suprasellar tumours (n = 321), parasellar tumours (n = 36) or retrosellar tumour (n = 1), and all of whom had undergone fundus photography and full-threshold visual field examination. The tumour spectrum included 336 pituitary gland tumours, 32 meningiomas, 89 craniopharyngiomas, 9 chiasmal gliomas and 35 other types of tumours or lesions. An age-matched control group was formed from the population-based Beijing Eye Study. Using fundus photographs and visual field examinations, glaucoma was defined by a neuroretinal rim shape not following the ISNT rule (Disc glaucoma group) and by an abnormal rim shape plus glaucoma-like visual field defects (Field glaucoma group). Type and size of the tumours were assessed on neuroradiological images. Five-hundred and one patients fulfilled the inclusion criteria. Disc glaucoma and Field glaucoma were detected significantly more frequently in the study population [34 (6.8%) patients and 31 (6.3%) patients, respectively] than in the population-based control group of the same ethnicity (1.3% ± 0.5%; p < 0.001). In multivariate analysis, presence of Disc glaucoma [odds ratio (OR) = 2.64; p = 0.016] and presence of Field glaucoma (OR = 3.01; p = 0.027) were significantly associated with tumour location [suprasellar > parasellar > intrasellar]. The same held true for tumour width (OR = 1.08; p = 0.002; and OR = 1.08; p = 0.003, respectively). Large perisellar tumours were associated with a glaucoma-like appearance of the optic nerve head in eyes. It may diagnostically and pathogenetically be of importance.

Glaucoma‐like optic neuropathy in patients with intracranial tumors

Abstract Purpose To examine frequency and associated factors of a glaucoma‐like appearance of the optic nerve head in patients with intrasellar, suprasellar or parasellar tumors. Methods The study included patients who were consectutively treated for intrasellar tumors (n=143), suprasellar tumors (n=321), parasellar tumors (n=36), or retrosellar tumor (n=1), and all of whom had undergone fundus photography and full‐threshold visual field examination. An age‐matched control group was formed from the population‐based Beijing Eye Study. Glaucoma was defined by neuroretinal rim shape plus glaucoma‐like visual field defects. Results Five‐hundred and one patients fulfilled the inclusion criteria. Disc‐Glaucoma and Field Glaucoma were detected significantly more frequently in the study population (34 (6.8±1.1%) patients and 31 (6.3±1.1%) patients, respectively) than in the population‐based control group of the same ethnicity (1.3% ± 0.5% (0.3%‐2.3%); P&lt;0.001). In multivariate analysis, presence of Disc‐Glaucoma and Field‐Glaucoma was significantly associated with tumor location (suprasellar &gt; parasellar &gt; intrasellar (OR=2.64; P=0.016; and OR=3.01; P=0.027, resp.)) and tumor width (OR=1.08; P=0.002; and OR=1.08; P=0.003, resp.). Conclusion Large perisellar tumors were associated with a glaucoma‐like appearance of the optic nerve head in eyes. It may diagnostically and pathogenetically be of importance and may give insight into the pathogenesis of normal‐pressure glaucoma.

Using the OHTS‐EGPS risk calculator with OctopusTM visual field testing

Abstract Purpose Assessing risk in ocular hypertensive (OHT)patients is not only of clinical importance for the patients with regard to their possible glaucomatous field damage but has major repercussions on their quality of life when making decisions about the use of eye drops for longer periods. Clinicians are not that good in estimating the risk hence the need for instruments to help them make a more evidence‐based decision. The EGPS group states that a methodological difference “ of using in a quarter of the patients another type of perimeter could explain the Hasard Ratio for the Pattern Standard Deviation (PSD) of 1.66 in EGPS and 1.27 in OHTS .Hence our interest to recalculate a conversion of the Octopus G1 program ( mostly used for glaucoma ) to the Humphrey 30‐2 in a Group of ocular hypertensives conform the inclusions of the OHTS thus providing a way to use the calculator more accurately. Methods 50 OHT patients recruited using the OHTS criteria were tested both with the Humphrey 30‐2 program and the Octopus G1 program. The Humphrey PSD values were plotted against the square root of the Loss of Variance (sLV) and a conversion formula was calculated Results Our data generated the following conversion formula: Y = 0.4X + 1.1 Conclusion Our conversion permits a proper use of the risk calculator in OHT patients. There has been an attempt to convert the values from Humphrey 30‐2 to Octopus 32 by Monhart based on the results of a study by Langerhorst. Another approach could be based on the algorithm described by Zeyen using HFA 24‐2 and G1 Octopus but proves difficult to use in daily practice. EGPS simply used "converted" indices by taking the square root of LV for PSD. Our formula is based on the same population as OHTS but yields different results

Spatial Pattern of Glaucomatous Visual Field Loss Obtained with Regionally Condensed Stimulus Arrangements

To assess the spatial distribution of glaucomatous visual field defects (VFDs) obtained with regionally condensed stimulus arrangements. Sixty-three eyes of 63 glaucoma subjects were examined with threshold-estimating automated static perimetry (full threshold 4-2-1 dB strategy with at least three reversals) on an automatic campimeter or a full-field perimeter. Stimuli were added by the examiner to regionally enhance spatial resolution in regions that were suspicious for a glaucomatous VFD. These regions were characterized by contiguous local VFDs, attributable to the retinal nerve fiber bundle course according to the impression of the examiner. The added stimulus locations were subsets of a predefined, dense perimetric grid. All VFD locations with P < 0.05 (total deviation plots) were assessed by superimposing the visual field records of all participants. Glaucomatous VFD loss occurred more frequently in the upper than in the lower hemifield, with a typical retinal nerve fiber-related pattern and a preference of the nasal step region. More than 50% of the eyes with predominantly mild to moderate glaucomatous field loss showed defective locations in the immediate superior paracentral region within an eccentricity of 3°. Conventional thresholding white-on-white perimetry with regionally enhanced spatial resolution reveals that glaucomatous visual field loss affects the immediate paracentral area, especially the upper hemifield, in many eyes with only mild to moderate glaucomatous visual field loss. Detailed knowledge about the spatial pattern and the local frequency distribution of glaucomatous VFDs is an essential prerequisite for creating regionally condensed stimulus arrangements for adequate detection and follow-up of functional glaucomatous damage.

New approach for the glaucoma detection with pupil perimetry

To calculate the pattern deviation for identifying abnormal points of pupil perimetry, and also to evaluate the grayscale display for distinguishing glaucomatous pupil field loss (abnormal test points) from normal pupil field (normal test points). Fourteen patients ranging in age from 51 to 80 years, who had normal-tension glaucoma (6 eyes) and primary open-angle glaucoma (8 eyes) were tested. Pupil perimetry (Kowa & Hamamatsu, Japan) was used to objectively measure the visual field. Also, to obtain a subjective visual field, the analysis was performed with a Humphrey Field Analyzer (30-2, Full threshold program, Carl Zeiss Meditec, Dublin). Of the 76 test points, the 22 surrounding points and the 3 points corresponding to the blind spot are excluded; and among the remaining 51 points, the 85th percentile value of pupil perimetry was calculated. The abnormal and normal test points were recorded, and the amount of positive or negative deviation of each test point from the normal median value for the corresponding test points was determined. We also used this technique to identify the value for distinguishing glaucomatous pupil field loss from the normal pupil field. This study could be improved by calculating the sensitivity and specificity of a certain cut-off value between the normative data and the glaucoma patients. The value for identifying both abnormal and normal test points was a negative deviation of -4. Based on these results, pupil perimetry gray scales were determined: white (< -3), 25% gray (from -4 to -8), 50% gray (from -9 to -13), 75% gray (from -14 to -18) and black (> -19). Glaucomatous pupil field losses were generally distinguished from the normal pupil field by use of a gray scale. Our studies demonstrated that, when a deviation of > -4 was regarded as an abnormal value, the detection of pupil perimetry exhibited improvement in glaucoma patients.

Natural History of Open-Angle Glaucoma

This article, based on the Early Manifest Glaucoma Trial (EMGT), provides prospective natural history data on progression of glaucomatous field defects in 3 of the most common glaucoma types. Cohort of EMGT patients randomized to the untreated control group and followed up to the time of progression, when treatment could be initiated. We evaluated 118 control patients: 46 with high-tension glaucoma (HTG), 57 with normal-tension glaucoma (NTG), and 15 with pseudoexfoliation glaucoma (PEXG). Visual fields were tested every 3 months with the Humphrey 30-2 Full Threshold test program. Linear regression analyses of the perimetric mean deviation (MD) values were performed, and the rate of progression was defined as the regression coefficient in decibels per year. Percentages of progressed eyes and time to progression were determined using EMGT event-based predetermined progression criteria derived from Glaucoma Change Probability Maps. The median and interquartile rates of visual function loss were -0.40 (1.05) dB/year overall and -0.46 (1.61) in HTG, -0.22 (0.65) in NTG, and -1.13 (6.13) in PEXG. Thus, interpatient variability was large. Mean rates were considerably higher than medians: -1.08 dB/year overall, -1.31 in HTG, -0.36 in NTG, and -3.13 in PEXG. Differences in median visual function progression rates among groups were statistically significant (NTG vs. HTG, P = 0.003; PEXG vs. non-PEXG, P<0.001). Progression was considerably and significantly faster in older than in younger patients (P = 0.002). By 6 years, 68% of patients had progressed overall, 74% of those with HTG, 56% of those with NTG, and 93% of those with PEXG (P = 0.012). Median time to progression also differed considerably among groups: 19.5 months in PEXG, 44.8 months in HTG, and particularly 61.1 months in NTG (P<0.0001). In this 6-year follow-up study, the median untreated rate of progression corresponded to advancing from normal visual function to blindness in approximately 70 years, whereas on the basis of the mean rate, visual function would show the same deterioration in approximately 25 years. Large differences existed among patients and different glaucoma types, with PEXG progressing considerably faster than HTG, and NTG progressing at the lowest rate.

Quantifying Retinal Nerve Fiber Layer Loss in Glaucoma Using a Model of Unilateral Hypertensive Pseudoexfoliation Syndrome

To correlate the amount of glaucomatous field loss with amount of retinal nerve fiber layer (RNFL) loss using a novel model consisting of eyes of subjects with pseudoexfoliation syndrome (PXS) in 1 eye only with elevated intraocular pressure, using the fellow eye as a marker of baseline healthy anatomy, allowing precise correlation by elimination of intersubject anatomic variation. In each eye with PXS we recorded standard automated perimetry mean deviation and the percentage loss of Stratus optical coherence tomography - RNFL thickness relative to the fellow non-PXS eye, and correlated these 2 measurements. Twenty-six subjects with unilateral hypertensive PXS were enrolled. Twelve of 26 eyes had glaucomatous visual field loss. In eyes without field defect there was a broad range of RNFL thickness loss from almost none to nearly 50%. In some of these eyes whereas RNFL thickness was within normal limits it was clearly reduced compared with the fellow eye. All eyes with field defect except one had lost greater than 50% RNFL thickness. This model of unilateral hypertensive PXS allows correlation of functional and structural loss in glaucoma while eliminating interindividual anatomic variability. It suggests that optical coherence tomography can have an important role in the diagnosis and management of early glaucoma before visual field loss is detected.

Fitness to drive in glaucoma patients‐ Preliminary study results

Abstract Purpose To develop a useful binocular 30° visual field criterion to predict safe driving behaviour in glaucoma patients by comparing perimetric data with an actual driving test on the road. Methods The sample will consist of 200 driving glaucoma patients, recruited in 2 university based glaucoma clinics (Ghent and Leuven, Belgium). Inclusion criteria are glaucomatous optic disc damage and/or glaucomatous field defects. Exclusion criteria are concomitant ocular disease, cataract &gt; LOCS 2, systemic disease or medication affecting the visual field. Data collection will include demographic and medical data, driving habits, and Mini Mental Status. A complete ophthalmic examination wil be done including Goldmann, SAP and Esterman visual field testing. In addition, UFOV test, stereopsis and contrast sensitivity testing will be performed. All subjects will perform an on the road driving test with a driving expert of the Belgian Institute for Traffic Safety. Subjects can pass, fail, or pass the test with limitations. An attempt will be made to develop an algorithm of visual field abnormalities that predict as accurately as possible the outcome of the practical driving test. Results Preliminary results of the first 50 included patients will be presented.

Otago Glaucoma Surgery Outcome Study: long‐term results of 841 trabeculectomies

To describe the long-term outcomes of trabeculectomies performed at Dunedin Hospital and followed in the Otago Glaucoma Surgery Outcome Study. Prospective non-comparative case series of 841 eyes of 607 patients who had first trabeculectomies for primary open- or closed-angle glaucoma at Dunedin Hospital between 1976 and 2005 and followed for a mean of 7.5 years (standard deviation 6.0). The probability of a trabeculectomy controlling the intraocular pressure at 21 mmHg or less at 1, 10 and 20 years was 0.96 (95% confidence interval [CI] 0.95, 0.97), 0.86 (95% CI 0.83, 0.89) and 0.79 (95% CI 0.74, 0.83), respectively. Visual acuity was maintained or improved between preoperative assessment and final follow up in 68% of cases. The probability of not being blind following trabeculectomy at 1, 10 and 20 years was 0.98 (95% CI 0.96, 0.98), 0.83 (95% CI 0.80, 0.87) and 0.70 (95% CI 0.64, 0.76), respectively. The proportion of those with glaucomatous field loss increased during follow up from 16% (44/283) at 0-5 years to 50% (10/20) for those with 21 or more years of follow up. A repeat drainage procedure was required in 65 eyes (8%) (56 Molteno implant insertions and 9 repeat trabeculectomies). Intraocular pressure was well controlled by trabeculectomy; however, a steady decline in intraocular pressure control, visual acuity and visual field occurred during follow up.

Tilted disc syndrome may mimic false visual field deterioration

Tilted disc syndrome is a congenital anomaly of the eye characterized by mostly upper temporal visual field defects. The aim of the present study was to evaluate the effect of gradual myopic correction in the improvement of visual field defects associated with tilted disc syndrome. The visual field was examined in 38 eyes of 24 patients using standard Goldmann perimetry. The isoptres IV-4e, I-4e, I-3e and I-2e were plotted. The defective isoptres were tested again with gradually increasing myopic correction until no further change was noted. The most common type of defect was a relative upper temporal defect (19 eyes). Temporal relative defects were found in five eyes, upper altitudinal field defects in six eyes, an enlarged blind spot in four eyes, and an inferior field defect in one eye. The visual field defect partly or totally disappeared with increased myopic correction in 18 (50%) eyes. The mean improvement was 17.0 +/- 6.2 degrees and the mean additional myopic correction was 3.1 +/- 1.5 D. Even a small change in near correction during visual field examination may imply worsened or improved visual field defects in tilted disc syndrome. To prevent a false interpretation of field deterioration in a patient with tilted disc syndrome and glaucoma, visual field assessment should include examination with the myopic correction that provides the maximal improvement of the defective visual field.

Canadian Glaucoma Study

To determine systemic and ocular risk factors for visual field progression in open-angle glaucoma. In the Canadian Glaucoma Study, a multicenter prospective longitudinal study of 258 patients (131 men and 127 women; median age, 65.0 years), baseline systemic measures included assessment of peripheral vasospasm and markers for hematopathology, coagulopathy, and immunopathology. Patients were followed up at 4-month intervals with perimetry, optic disc imaging, and a standardized interventional protocol for intraocular pressure control. Univariate and proportional hazards models were used to identify factors that predicted progression. Visual field progression with standard automated perimetry. Median follow-up was 5.3 years, with 167 patients (64.7%) completing 5 years or more and 67 patients (26.0%) completing 7 years or more. Abnormal baseline anticardiolipin antibody levels (hazard ratio [HR], 3.86; 95% confidence interval [CI], 1.60-9.31), higher baseline age (HR per year, 1.04; 95% CI, 1.01-1.07), female sex (HR, 1.94; 95% CI, 1.09-3.46), and higher mean follow-up intraocular pressure (HR per 1 mm Hg, 1.19; 95% CI, 1.05-1.36) before progression were associated with progression. The Canadian Glaucoma Study identified 4 independent predictive factors for glaucomatous field progression. Application to Clinical Practice While confirming the importance of intraocular pressure in glaucoma progression, this study determined other risk factors that merit awareness.

Influence of Diabetes on the Validity Glaucoma Screening by Frequency Doubling Perimetry: A Hospital-Based Study in Oman

A hospital-based study was conducted in 2007 in Oman to determine the validity of frequency doubling perimetry (FDP). The authors have compared the ability of FDP to detect glaucoma among patients with and without diabetes. This was a validity study of the screening procedure. An ophthalmologist and an optometrist examined Omani persons >30 years of age with and without diabetes. They determined glaucomatous field changes by using FDP. The glaucoma specialist labeled the eye and the person as suffering from glaucoma if two criteria were present: (1) optic cup disc and other retinal changes suggestive of glaucoma and (2) field changes on automated perimeter suggestive of glaucoma. Ocular pressure was measured with a Tono-Pen (Medtronic Ophthalmics, Jacksonville, FL). We calculated the validity of glaucoma screening by FDP among persons both with diabetes and without diabetes. We examined 111 eyes of 56 Omani patients (55 eyes of 28 patients with diabetes and 56 eyes of 28 persons without diabetes). Two persons had a history of glaucoma in both eyes. Glaucoma screening by FDP detected five eyes (two eyes of patients with diabetes and three eyes of persons without diabetes) with glaucoma. The specificity of glaucoma screening among those with and without diabetes was 97.4% and 97.3%, respectively. The sensitivity was 6% and 11%, respectively, in these two groups. Validity of glaucoma screening by FDP is not different among those with and without diabetes. In countries with high rates of diabetes, FDP could be used as a first-level screening tool for glaucoma.

Is open‐angle glaucoma caused by impaired cerebrospinal fluid circulation: around the optic nerve?

Chronic open-angle glaucoma is the most frequent type of glaucoma and a leading cause for blindness. The role of intraocular pressure (IOP) in the pathogenesis of open-angle glaucoma has been challenged by patients with typical glaucomatous optic disc changes and visual field loss in whom the IOP never exceeded normal values (normal-tension glaucoma), as well as by patients with persistently elevated IOP who do not develop glaucomatous disc or field changes. Recent research has demonstrated that the cerebrospinal fluid (CSF) is not evenly distributed in all CSF spaces and that the subarachnoid space of the optic nerve can turn into a CSF compartment on its own. The biochemical components in this optic nerve compartment can differ markedly from normal CSF and some of its components (such as L-PGDS) may produce a toxic effect on the optic nerve and may therefore play an important role in the pathophysiology of open-angle glaucoma.

381 Un suivi à long terme des effets des béta-bloquants sur les patients atteints de glaucome

The purpose of this prospective, comparative, non randomized study was to evaluate the influence of betaxolol and timolol on the visual function and IOP in the patients with primary open angle glaucoma. The study was performed in the University Eye Clinic Sarajevo in the period from June 2003 to March 2005. 20 patients were treated with 0,25% betaxolol, and 23 patients were treated with 0,5% timolol. Of this 43 patients, 33 could be followed up in a 35 months period. Inclusion criteria: subject >35 years old with POAG; both eyes of subjects followed through study, patients with glaucomatous field defect on Octopus, CLV> 4 dB; no visual acuity less than 0,4 and IOP>21mmHg. Exclusion criteria: patients with systemic disease, pathologic myopia, ocular disorders, and those with contraindication to beta-blockers, neurological disease, eye and head trauma previously. Each examination included visual field measurement, slit lamp examination, intraocular pressure, fundoscopy, blood pressure measurement. Automated perimetry was performed with Octopus G1 program (baseline, 6, 12, 18, 35 month). Of the 43 patients initially enrolled, 10 patients discontinued treatment. Patients were initially comparable in terms of IOP, MS and MD. Both drug lowered IOP. The reduction in IOP in timolol treated group was more pronounced than in the group of patients treated with betaxolol, but the difference was not statistically significant. The visual field improved during the first 12 months and remained more or less stable for the rest of observation period. Patients treated with betaxolol had statistically significant lower averaged mean defects (p<0,05). We may suppose that selective beta 1-blockers have better effects on blood flow of optic nerve head than non-selective beta-blockers and on that way protect ganglion cells and nerve fibers. That in suggested after analysis of visual field. In few publication were publicized some results as we have found but this neuroprotective effect was not explained. The treatment of glaucoma patients is a challenge. It is well known that elevated IOP is a risk factor for progressing visual field damage. Despite well-controlled IOP, visual field damage could be find. Our results indicate that locally applied beta-blockers are reducing IOP over a long period. Timolol tended to have a better effect on IOP than did betaxolol, but betaxolol had a better influence on the visual field.

Classifying Patterns of Localized Glaucomatous Visual Field Defects on Automated Perimetry

To classify the classic patterns of glaucomatous visual field defects on automated perimetry and to study their proximity to fixation. Cross-sectional observational study. About 1120 full threshold 30-2 reliable visual fields of glaucoma patients were analyzed by 2 glaucomatologists. Classically described patterns of visual field defects were identified on the pattern deviation plot and definitions proposed. Interreader agreement between 3 independent (not involved in the classification) readers was determined. Proximity to fixation of the different patterns was assessed. Interreader agreement with 3 readers was found to be 93% or more between any 2 readers using the present system of classification. Central fixation was seen to be involved in 45% of the glaucomatous visual field defects studied overall. The proposed definitions of topographical glaucomatous field defects based on the pattern deviation probability plot are simple to use in clinical practice with good interreader agreement.

Change in Optic Nerve Head Topography in Progression of Early Glaucoma

Purpose: To investigate the clinical manifestation and the structural optic disc changes according to the development of reproducible visual field defects in a group of preperimetric patients converting to early glaucoma. Methods: Standard automated perimetry (Humphrey Field Analyzer) was performed every six months in 294 preperimetric patients. Each subject was classified as either converter or non-converter according to glaucomatous visual field changes, and the clinical manifestations were analyzed retrospectively. Sequential optic disc images were obtained using the TopSS scanning laser ophthalmoscope (TopSSTM) and optic disc parameters were measured to determine if any change had occurred. Results: A total of 44 eyes from 44 subjects (14.9%) in 294 patients subsequently developed early glaucomatous field loss (converters). The progression rate of visual field defect is 0.43dB/year. In respect to age, sex, refractive error, and diabetes mellitus, no significant differences were observed. Elevated IOP, hypertension, and family history of glaucoma were detected more frequently in the converter group than in the non-converter group. Among TopSS parameters, cup-to-disc ratio, effective area, volume above, maximum slope, and neuroretinal rim area showed statistically significant change. Changes of the neuroretinal rim were prominent in superior and inferior sectors. Conclusions: Among TopSS parameters, cup-to-disc ratio, effective area, volume above, and neuroretinal rim are useful in detecting the progression of glaucoma. Furthermore, neuroretinal rim changes in each sector may provide clinically relevant information in detecting and monitoring the progression of glaucoma.

Glaucoma detection using different Stratus optical coherence tomography protocols

To examine and compare the diagnostic accuracy of retinal nerve fibre layer (RNFL) thickness measurements using different Stratus optical coherence tomography (OCT) scanning protocols. Stratus OCT data for 90 healthy subjects and 62 glaucoma patients with mild or moderate visual field loss were prospectively collected and analysed using four RNFL thickness protocols that differed in terms of image resolution and number of scans. Cut-off levels corrected for age and refractive error were defined by reference values derived from an independent normal database. Sensitivity and specificity were calculated for average RNFL thickness for the full circle scan, and for the quadrant and clock hour circle scan sectors at p < 5% and p < 1% cut-off values. Regular- and high-resolution images performed equally well, and single best-quality scans were as good as the average of three scans to distinguish between healthy and glaucomatous eyes. Full circle RNFL thickness yielded similar or better diagnostic accuracy than that of sectors. Sensitivities ranged from 84% to 87% and specificities from 89% to 93% for full circle RNFL thickness at the p < 5% cut-off level. The abilities of four different Stratus OCT RNFL thickness protocols to distinguish between eyes with predominantly mild glaucomatous field loss and healthy eyes were very similar. Thus diagnostic accuracy did not differ between high- and regular-resolution protocols, nor between global (full circle) and localized (sector) OCT parameters, which suggests a diffuse component in early glaucomatous RNFL damage.

Nerve Fiber Layer Thickness in Glaucoma Patients With Asymmetric Hemifield Visual Field Loss

To investigate the presence of retinal nerve fiber layer (RNFL) thinning and determine the relationship between RNFL thickness and visual field sensitivity loss in glaucoma patients with asymmetric hemifield visual field loss. Thirty glaucoma patients with asymmetric hemifield visual field loss and 30 normal control subjects were included in the study. RNFL thickness was measured by optical coherence tomography and visual field sensitivity was measured by automated perimetry. Glaucoma patients with advanced visual field loss restricted to 1 hemifield and early or absent glaucomatous field loss in the other hemifield on the basis of the visual field data were included. Visual field sensitivity and mean deviation (MD) were averaged separately in each of the 2 hemifields. The hemifields in each eye were categorized as early (MD>or=-6 dB) and advanced (MD<-6 dB) glaucomatous hemifields. RNFL thickness measurements in corresponding (eg, superior peripapillary quadrant with inferior hemifield) advanced glaucomatous hemifields (59+/-16 microm) were significantly (P<0.001) lower than in corresponding early glaucomatous hemifields (90+/-25 microm). The mean RNFL thickness in corresponding advanced and early glaucomatous hemifields were significantly lower than in normal control subjects (P<0.0001). On the basis of the normative database supplied by optical coherence tomography software, 100% and 43% of eyes had abnormal RNFL thickness in corresponding advanced and early glaucomatous hemifields, respectively. A linear correlation was found between RNFL thickness and MD in the early (r=0.6; P<0.001) and advanced (r=0.5; P=0.007) glaucomatous hemifields. RNFL thinning was present in corresponding hemifields of glaucomatous eyes with minimal visual field defect and correlated with visual field sensitivity loss. Measurement of RNFL thickness has potential for detection of early nerve fiber loss owing to glaucoma.