Diabetes in primary open-angle glaucoma patients with inferior visual field defects

We reviewed the charts of 144 randomly selected patients with primary open-angle glaucoma who had Aulhorn's stage 1, 2, or 3 visual field defects to investigate whether primary open-angle glaucoma patients with predominantly inferior visual field defects had a higher prevalence of diabetes mellitus than primary open-angle glaucoma patients without such visual field defects. Of the 59 patients with mainly inferior visual field defects in one or both eyes, 19 (32%) had diabetes mellitus, while 11 of 85 (13%) patients without such defects had diabetes mellitus. This difference was statistically significant (P = 0.0096). These results suggest that primary open-angle glaucoma patients with predominantly inferior visual field defects in one or both eyes are more likely to have diabetes and that such patients with no known history of diabetes may benefit from glucose tolerance testing to detect occult impaired glucose tolerance or diabetes mellitus.     

Foveal dysfunction and central visual field loss in glaucoma

OBJECTIVE: To determine whether foveal function distal to the ganglion cell layer is an independent predictor of central visual field function in glaucoma. SETTING: University affiliated hospital and private practice. PARTICIPANTS: Twenty-seven eyes (27 patients) with normal-pressure glaucoma, 10 eyes (10 patients) with primary open-angle glaucoma, and 47 eyes of 47 matched normal volunteers. INTERVENTION AND MAIN OUTCOME MEASURES: Foveal cone electroretinogram (ERG) amplitude, relative optic cup to disc area and their relations to Humphrey full-threshold 30-2 visual field central 4-point mean total deviation (C4MTD) and pattern deviation (C4MPD). RESULTS: Foveal cone ERG amplitude was subnormal in 14 (37.8%) of the 37 glaucomatous eyes and lower in the glaucoma group compared with normal eyes (P<.01). The C4MTD and C4MPD were lower in glaucomatous eyes with subnormal amplitudes compared with those with normal amplitudes (P<.01 and P<.05, respectively). Amplitude was directly correlated with C4MTD (P<.01) and C4MPD (P<.01). Relative optic cup to disc area was inversely correlated with C4MTD (P<.001) and C4MPD (P<.001). Partial correlation analysis revealed that amplitude and relative optic cup to disc area were independent predictors of C4MTD and C4MPD. CONCLUSION: Foveal function distal to the ganglion cell layer and optic disc cupping independently predict central visual field function in glaucoma.     

Mathematical optimization of glaucoma visual field screening protocols

There is potential for significantly shortening the time required for visual field screening protocols by a precise specification of the number, exact location, and sequence of points to be tested. Through statistical and mathematical methods, protocols have been developed for maximizing the probability of detecting at least one visual field defect in a subject who is a risk for early glaucomatous field loss. The mathematical formulation was derived in a generalized manner so that it could be applied to most kinetically or statically determined visual field screening methods.     

Frequency of asymmetric visual field defects in normal-tension and high-tension glaucoma

OBJECTIVE: The purpose of the study was to evaluate the frequency of asymmetric visual field loss at presentation in patients with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG). DESIGN: A retrospective cross-sectional study design was used. PARTICIPANTS: Four hundred and three NTG patients and 337 consecutive HTG patients (consecutive diagnoses between 1986 and 1996). INTERVENTION: Analysis of the frequency of unilateral field loss presentations in NTG and HTG. The visual fields of fellow eyes were compared to determine the side of more severe field loss. For the NTG patients, the relationship between the side with greater field loss and corresponding intraocular pressure (IOP) was investigated. MAIN OUTCOME MEASURES: Humphrey field analyzer mean defect (MD) and mean diurnal IOP. RESULTS: In the NTG group, 101 (25%) patients presented with unilateral field loss. The proportion of cases with unilateral field loss decreased with increasing age of presentation (chi-square test for trend = 26.9; P < 0.0001). Sixty-four percent of the patients had unilateral field loss in the left eye. Sixty-eight percent of the cases with bilateral field loss had a higher MD in the left eye. The diurnal IOP was estimated as 0.23 +/- 0.068 mmHg (mean +/- SE) higher in the left eye (P = 0.001). In the HTG group, 104 (31%) patients presented with unilateral field loss. The proportion of cases with unilateral field loss decreased with increasing age of presentation (chi-square test for trend = 4.6; P = 0.03). Right and left eyes had an equal chance of having field loss in unilateral cases and of being the side of more advanced field damage in bilateral cases. CONCLUSIONS: The frequency of cases with unilateral field loss was similar in HTG and NTG patients. Patients with unilateral field loss at presentation were more likely to be at the younger end of the age range. In the NTG population we studied, the left eye was more frequently the side of onset of field loss and 2.1 times more likely to present with a greater field defect than the right eye. In HTG patients, right and left eyes showed an equal chance of being the side of onset of field damage and the more affected side.     

Effects of bifemelane hydrochloride on atherosclerosis in aged rats fed low-calcium diets

The preventative effects of bifemelane (4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride) on atherosclerosis in aged rats fed low-calcium diets were investigated. Male 18-month-old Wistar rats were maintained for 90 days on the following: (A) standard diet (n = 7), (B) low calcium, low magnesium, high aluminium diet (n = 8), (C) standard diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6), (D) low calcium and magnesium, high aluminium diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6). All groups were give these diets and water ad lib for 90 days, after which blood samples were taken from the abdominal aorta and samples of aorta were examined for atherosclerotic changes. The serum concentrations of the following were determined: calcium, magnesium, zinc, aluminium, inorganic phosphorus, cholesterol, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, lactate dehydrogenase, cholinesterase, creatine phosphokinase, blood urea nitrogen and N-terminal parathyroid hormone. The only significant differences between the groups in serum chemistry were reduced concentrations of cholinesterase and magnesium in groups B and D, increased aluminium in group B, and increased N-terminal parathyroid hormone in groups B and D. In groups C and D the atherosclerosis was much improved compared with that in groups A and B. It appears that bifemelane largely prevents atherosclerosis caused by calcium deposition in the arteries of rats fed low-calcium diets, due to its effect in maintaining magnesium and calcium in bones.     

Improving the prediction of visual field progression in glaucoma using spatial processing

AIMS: To estimate the cost of population screening for haemochromatosis in Australia and to compare the cost of alternative screening strategies. METHODS: The costs of screening for haemochromatosis were analysed in a hypothetical study using transferrin saturation as the primary screening test, with confirmation of the diagnosis by either liver biopsy or DNA testing for the recently-described haemochromatosis gene. RESULTS: Screening, with confirmation of the diagnosis by liver biopsy, would cost between US$5079 and US$8813 per case detected (excluding administrative costs), depending on the screening strategy (Aust$ = US$0.80). If a DNA test were used instead of liver biopsy, the cost would be reduced to an estimated US$3954-US$4410 per case. This would be further reduced to US$2457 by detection of additional cases by screening family members. The least costly strategy utilised a transferrin saturation threshold of 55% and DNA testing for confirmation of the diagnosis; however, a transferrin saturation threshold of 45% increased the cost only marginally. The initial screening step (transferrin saturation) accounted for 74%-94% of the estimated cost of the screening programme. CONCLUSIONS: Screening for haemochromatosis using transferrin saturation involves relatively modest costs which may be recovered if complications of haemochromatosis can be prevented by early detection and treatment. The most cost-effective strategies utilised transferrin saturation for initial screening, followed by DNA testing. Reduction in the cost of transferrin saturation would lead to a significant reduction in total screening costs. Additional benefits of a screening programme include detection of other iron overload disorders and iron deficiency.     

Influence of refraction on the visual field defects in normal tension glaucoma and primary open angle glaucoma eyes

The prevalence of normal tension glaucoma (NTG) or primary open angle glaucoma (POAG) is higher in myopic populations and the prevalence of myopia and NTG is relatively high in the Japanese. To evaluate the influence of myopic refractive error on the central visual field defect in NTG eyes, the data obtained from NTG eyes with the Humphrey Visual Field Analyser were analysed in comparison with those from POAG eyes. One hundred and twenty NTG eyes and one hundred and ninety-seven POAG eyes were included. All of them had clear ocular media, but no myopic degeneration in the fundus. Multiple linear regression analysis was performed with a dependent variable of the deviation of the measured threshold value from normal reference value (total deviation, STATPAC) and independent variables of refractive error and mean deviation (STATPAC). Myopic power was found to be positively correlated with the depression in the lower papillo-macular area in both NTG and POAG eyes, and it was negatively correlated with the depression in an upper arcuate area extending just nasal to the fixation only in NTG eyes.     

Association between watershed zone and visual field defect in normal tension glaucoma

In order to evaluate the association between the watershed zone and glaucomatous optic damage, we performed indocyanine green fluorescence angiography with a scanning laser ophthalmoscope in 54 eyes of 27 patients with normal tension glaucoma. The visual field indices were measured with a Humphrey Field Analyzer. We identified 8 eyes (14.8%) of 7 patients with a watershed zone not including the optic nerve head (type I), 32 eyes (59.3%) of 20 patients with the zone partially including the optic nerve head (type II), and 14 eyes (26.0%) of 10 patients with the zone including the optic nerve head (type III). Of the total of 27 patients, 10 patients (37.0%) had different types in each eye. In these patients, the mean deviation (MD) of visual field indices was worse in the eye with the watershed zone which included a larger part of the optic disc than in the contralateral eye (p < 0.05). Conversely, the eye with worse MD than the contralateral eye had a watershed zone which included a larger part of the optic disc than the other eye (p < 0.05). The location of watershed zone appeared to influence the progression of the visual field defect.     

A comparative study of visual field damage in low-tension and primary open-angle glaucoma

Methods to encapsulate biological materials are now widely used. Sometimes bioencapsulation is considered as a universal technique conducting to identical results independently on the biological material used. For instance, a similar behavior is frequently waited for different strains of immobilized microorganisms without taking into account substantial differences in its physiological and morphological characteristics. Often interactions with the matrix support are also neglected. Thus, some concepts developed throughout all these years working in bioencapsulation merits to be revisited.     

Blue-on-yellow visual field and retinal nerve fiber layer in ocular hypertension and glaucoma

BACKGROUND AND OBJECTIVE: It has been suggested that the clinically detectable changes of the blue-on-yellow (B/Y) visual field and retinal nerve fiber layer (RNFL) may precede standard white-on-white (W/W) visual field defects in the progression of glaucoma. The aim of this study was to test the relationship between the results of B/Y visual fields and semiquantitative RNFL evaluation in corresponding areas and to determine how the B/Y visual fields and RNFL scores label the normal W/W perimetry hemifields in patients with glaucoma and ocular hypertension. DESIGN: A cohort study. PARTICIPANTS AND METHODS: Monochromatic RNFL photographs of 32 normal subjects and 29 patients with ocular hypertension and different stages of glaucoma were assessed in a masked fashion. The B/Y and W/W visual fields (program 30-2) were examined with a Humphrey perimeter. The results of both visual fields were adjusted for the patients' age and lens transmission index measured with a lens fluorometer. MAIN OUTCOME MEASURE: Mean deviation (MD) of visual field and semiquantitative score of RNFL loss were measured. RESULTS: The total and hemifield MD values of B/Y and W/W visual field showed a statistically significant correlation with diffuse and overall score of RNFL loss in corresponding areas. The hemifield MD values of B/Y perimetry obtained from "normal" W/W hemifields of patients with early glaucoma were well correlated (r = -0.56) with respective RNFL loss scores found to be abnormal in 84% of hemispheres. The difference between the hemifield MD values of B/Y perimetry obtained from normal W/WAN hemifields of patients with ocular hypertension and patients with early glaucoma was not statistically significant (analysis of variance). The respective B/Y hemifield data of normal subjects were statistically significantly different from the data of patients with ocular hypertension and early glaucoma. CONCLUSIONS: The hemifield MD values of B/Y perimetry correlate well with semiquantitative scores of RNFL loss obtained from the corresponding hemisphere. The B/Y perimetry as well as RNFL assessment may show glaucomatous defects in a hemifield found to be normal on W/W perimetry. In subjects with ocular hypertension, the functional damage detected by B/Y perimetry may, in some cases, precede RNFL defects on conversion to glaucoma.     

Influence of axial length on visual field defects in primary open-angle glaucoma

With the high frequency of myopia in Taiwan, potential complications or associated conditions, such as glaucoma, are of great concern. To investigate the role of axial length in glaucoma, we enrolled 307 primary open-angle glaucoma (POAG) patients from 1986 through 1996. For the control group, 124 persons were recruited from a survey of a non-glaucoma population and the Ophthalmology Out-patient Department of the National Taiwan University Hospital. Routine eye examination, stereophotography of the optic disc, automated visual field tests, and A-scan ultrasonography were performed on each patient. The Glaucoma Hemifield test was used for analysis of visual field results. The mean axial length was longer in the POAG group than in the control group, especially in the younger age groups (40-59 yr). The POAG group was divided into a short-axial-length (SAL, axial length < 26 mm) group and a long-axial-length (LAL, axial length > or = 26 mm) group. Both subgroups had the deepest visual field defects in the upper and lower nasal areas. The LAL group had deeper visual field defects and the defects were more frequently involved in all sectors analyzed than the SAL group defects. The upper visual field had deteriorated more in the SAL group, whereas the depth of scotoma was similar in the upper and lower hemifields in the LAL group. Our results support the idea that glaucoma patients have a longer axial length than people without glaucoma, and that visual field defects are more pronounced in patients with LAL than in those with SAL.     

Patterns of visual field progression in patients with retinitis pigmentosa

OBJECTIVE: The purpose of the study was to determine whether distinct patterns of visual field progression are present in patients with retinitis pigmentosa (RP) and to evaluate the correlation between these patterns, if present, and different genetic subtypes of RP. DESIGN: A retrospective analysis of patterns of visual field progression in RP was performed. PARTICIPANTS: Visual fields of 162 patients with RP, including 55 with type 2 Usher syndrome, who had at least 3 Goldmann visual field examinations during a period of at least 3 years were reviewed. MAIN OUTCOME MEASURES: Goldmann visual fields. RESULTS: Visual fields of 86 patients could be classified into one of three specific patterns of visual field progression. Pattern I included those patients with a progressive concentric loss of visual fields; pattern II included those with visual field loss that began superiorly and subsequently developed an arcuate scotoma that progressed either from the nasal (IIA) or the temporal (IIB and IIC) side; and pattern III included patients whose visual field loss was characterized initially by a complete or incomplete midperipheral "ring scotoma" that broke through into the periphery. The end stage of all these patterns was a residual central visual field, sometimes also associated with a small peripheral island. In 53 of the 162 patients, the pattern of visual field loss could not be categorized because of an advanced stage of field loss at the time of the initial examination. CONCLUSIONS: Distinctive patterns of visual field progression can be observed in patients with retinitis pigmentosa and type 2 Usher syndrome. There were no intrafamilial variations in the pattern of visual field loss in our data on 24 patients from 11 families. Within certain genetic subtypes, there was a predilection for a preponderance of a specific pattern of visual field progression. Future studies may be able to correlate these patterns of visual field loss with different genetic mutations. A greater understanding as to why certain patterns of field loss exist could potentially provide greater insight into the various pathogenetic mechanism(s) by which photoreceptor cells degenerate in this group of patients.     

In vivo morphometry of the lamina cribrosa and its relation to visual field loss in glaucoma

Academic medical centers (i.e., teaching hospitals) and academic medical practices are under pressure to control costs to compete with for-profit health care institutions. The authors explain how academic physician managers who want to control costs wisely must first understand the cost structure of the medical center or practice and compare that structure with those of for-profit institutions. Doing this requires a firm understanding of how to use a valuable tool, financial statement analysis, to assess an institution's health and performance. Such analysis consists of calculating a variety of financial ratios (e.g., operating income divided by revenues; net income divided by total assets) and then comparing them with the corresponding ratios that are considered industry norms. Three types of financial statements (defined in detail) lend themselves to this approach: the balance sheet, income statement, and statement of cash flows. The authors define standard financial ratios, point out their uses and limitations, and emphasize that a ratio's meaning derives from comparing it with the corresponding benchmark ratio in the industry as a whole. Ratios should be used not as the end point of assessing financial status, but as ways to identify possible problems that require further investigation. Analysis of trends of ratios over time within an institution is a complementary approach. The authors then discuss the use of ratios in three standard types of institutional evaluation: of performance, of liquidity and leverage, and of strategic planning. In addition, they present the financial statement of a fictitious academic medical center as an example of how to use ratios for financial statement analysis. The authors emphasize that the key to using the ratios they discuss and hundreds of others is first to decide what question needs answering and then to choose the relevant ratios to provide a basis for finding the answer.     

Clinical use of a new method for visual field damage classification in glaucoma

Eighty-five consecutively seen HIV-positive persons with oral candidiasis were evaluated for clinical characteristics, staging of HIV disease, quantitation of candidal colony formation, and response to systemic antifungal treatment with Nizoral (ketoconazole). Fifty-five had CD4 counts less than 200. There was an inconsistent association between clinical signs, patient symptoms, CD4 counts, and candidal colony-forming units. However, there was a trend toward higher colony-forming unit counts (> 500) in patients with lower CD4 cells (< 200). Sixty-five patients had a complete clinical response to the ketoconazole treatment (200 mg daily for 7 days), even though 81% of posttreatment cultures remained positive. Nonsmokers were more likely to respond to antifungal treatment when compared with smokers, and there was a slight tendency for complete responses when colony-forming unit counts were low. The most common lesion presentation was a combination of the white (pseudomembranous) and red (erythematous) forms. Forty-nine percent had complaints of pain. The variable responses indicated the importance of flexible dose-time and drug considerations in antifungal management. Candida albicans was the predominant species.     

Quantitative estimation of retinal nerve fiber layer height in glaucoma and the relationship with optic nerve head topography and visual field

During the evolution of normal cells into cancer cells, the occurrence of multiple mutations results in genetic instability. Mutations in DNA repair genes such as those of mismatch and excision repair predispose the carriers of these mutations to cancer by increasing the level of genomic instability. A variety of chromosome aberrations, such as abnormal ploidy, whole chromosome loss or chromosome amplification are commonly observed in cancer cells. From one cell division to the next, mammalian cells pass through an organized series of controlled events referred to as the cell cycle. In order to pursue an ordered series of molecular events, the initiation of an event during cell cycle progression is dependent on the successful completion of an earlier event. The cell cycle is divided into two major phases, namely, M(mitotic) phase and interphase. Interphase can be further divided into three distinct phases termed G1 (gap 1), S(DNA synthesis) and G2(gap2) phases (Fig. 1). Along with the machinery that promotes cell cycle progression, cells are also equipped with cell cycle checkpoints that ensure correct ordering of events in the cell cycle. The idea of "the cell cycle checkpoint" was first introduced by Hartwell and Weinert (1989) as "the arrest of a cell at a particular phase of the cycle due to a lack of appropriate signals for cell cycle progression". Until the checkpoint machinery receives the appropriate signal, the cell will not be allowed to make transition from one phase of the cell cycle to the next. Thus, the major role of checkpoint control is to minimize somatic genetic alterations and/or events affecting cellular survival. When one or more components of a cell cycle checkpoint are mutated, the chances of genetic instability during one round of the cell cycle increase accordingly with consequent acceleration of cellular evolution from the normal to the cancerous state. Therefore, mutations in checkpoint controls may predispose cells to cancer by causing genomic instability. In this review, I will focus on the potential roles of cell cycle checkpoints in the progression of malignancy.     

Early detection of visual field progression in glaucoma: a comparison of PROGRESSOR and STATPAC 2

AIM: To compare the performance of PROGRESSOR (pointwise linear regression) and STATPAC 2 (comparison with baseline values) in detecting early deterioration in the visual fields of glaucoma patients. METHODS: Visual field series from 19 untreated normal tension glaucoma eyes which were deteriorating on clinical grounds were analysed by PROGRESSOR and STATPAC 2. Progression criteria for PROGRESSOR were (1) inner points: slope < -1 dB/year, p < 0.05 and (2) edge points: slope < -2 dB/year, p < 0.05. Criteria for STATPAC 2 were p < 0.05 change probability for any point on three consecutive fields. Detection time was defined as the time interval between the initial field and the first field in which at least one progressing point was identified. Detection times produced by the two techniques were compared. RESULTS: PROGRESSOR and STATPAC 2 agreed on progression in all 19 eyes. Mean detection time for PROGRESSOR was 1.077 (SD 0.985) years and for STATPAC 2 was 2.161 (1.357) years. PROGRESSOR detected progression sooner than STATPAC 2 in 18 eyes (p < 0.01), Wilcoxon matched pairs signed rank test). PROGRESSOR detected progression earlier by a mean of 1.085 (0.936) years. CONCLUSIONS: PROGRESSOR consistently detected progression earlier than STATPAC 2. The PROGRESSOR software is a useful tool for the early detection of visual field deterioration in glaucoma.     

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

The role of cysteinylglycine S-conjugate dipeptidases in the intrahepatic mercapturic acid pathway was investigated in rat liver. Subcellular compartmentation studies and liver perfusions were performed using monochlorobimane and bimane S-conjugates as model compounds. The major part (over 95%) of total hepatic cysteinylglycine S-conjugate dipeptidase activity was located in the cytosol. Lower specific activity appeared in the canalicular plasma membrane fraction. Similar hepatic localization of dipeptidase activity was seen in the guinea pig. In intact rat liver perfused with monochlorobimane, the major products were the glutathione S-conjugate (mBSG) and the cysteinylglycine S-conjugate (mBCG) in bile. Minor amounts of the cysteine S-conjugate (mBCys) and the mercapturic acid (mBNAc) were formed, indicating a limitation in further metabolism of the dipeptide S-conjugate in the biliary space. However, when the dipeptide S-conjugate was offered to the sinusoidal space in liver perfusions, substantial uptake and conversion to mBNAc was observed, and only trace amounts of the infused dipeptide appeared in bile. The data suggest that cytosolic cysteinylglycine S-conjugate dipeptidase as identified here is involved in hepatic mercapturic acid formation from sinusoidal cysteinylglycine S-conjugates. This is especially of significance for species such as guinea pig and human, in which dipeptide S-conjugates are generated in the sinusoidal domain of the liver due to the presence of high gamma-glutamyltranspeptidase activity.