Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguish between normal and glaucomatous optic nerve heads, and between glaucomatous subjects with and without field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjects with elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10); subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects with glaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degrees image series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the 14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume above reference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) height variation contour (variation in relative nerve fibre layer height at the disc margin). Data were analysed using analysis of covariance, with age as the covariate. RESULTS: Volume above reference, third moment in contour, and mean height contour were significantly different between each of the three diagnostic groups (p < 0.001). Height variation contour showed no significant difference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variables measuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1) subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerve heads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality. This study did not directly assess the ability of the HRT to identify patients at risk of developing glaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will be in the documentation of change within an individual over time.     

The role of early trabeculectomy in the control of chronic simple glaucoma

Seventy patients of bilateral chronic simple glaucoma with a mean age of 59.7 years, an intra-ocular pressure over 25 mmg Hg, optic disc cupping, and without visual field loss were selected. The eye with higher intra-ocular pressure or the larger optic disc cup was treated by early trabeculectomy while the other eye of the same patient was subjected to medical therapy with topical beta blockers for 3 years (without any surgical treatment). Both the eyes of 70 patients were compared after 3 years. Eyes which had undergone trabeculectomy had a mean intra-ocular pressure of 11.7 mm Hg against 18 mm Hg in the medically treated eyes. Surgically treated eyes had decrease in the mean cup : disc ratio (from 0.54 : 1 to 0.48 : 1) whereas medically treated eyes showed an increase from 0.41:1 to 0.51: 1. Visual field loss occurred in 3/70 operated eyes and in 27/70 medically treated eyes. Twenty-one of 70 treated eyes developed cataract and 12 of these required cataract surgery. Only 18/70 medically treated eyes developed cataracts but none of these required cataract surgery. Early trabeculectomy in cases of chronic simple glaucoma resulted in a large reduction of intra-ocular pressure and consequently reduced the size of optic disc cup and the chances of visual field loss.     

Trabeculectomy with releasable sutures: a prospective, randomized pilot study

OBJECTIVE: To compare the short-term and long-term efficacy of using releasable sutures vs conventional interrupted sutures for scleral flap suturing in trabeculectomy. DESIGN: A prospective randomized study. SETTING: A university-affiliated referral eye hospital. PATIENTS: Thirty consecutive patients requiring trabeculectomy for uncontrolled primary glaucoma. INTERVENTION: Fifteen patients underwent trabeculectomy with permanent interrupted sutures; the same number underwent trabeculectomy with releasable sutures. MAIN OUTCOME MEASURES: Incidence of short-term shallowing of anterior chamber or hypotony and related complications, and long-term intraocular pressure control and bleb score. RESULTS: The mean percentage reduction in intraocular pressure on day 1 in the group with releasable sutures was 55.2%, while only a 0.8% reduction in anterior chamber depth was noted. This compared with figures of 59.3% and 10.1%, respectively, in the group without releasable sutures. Hypotony (intraocular pressure < or =6 mm Hg) was noted in 8 (53%) of cases without releasable sutures and 3 (20%) of cases with releasable sutures. Shallow anterior chamber (central anterior chamber depth, < or =1 mm) was noted in 5 (33%) of cases without releasable sutures and 1 (7%) of cases with releasable sutures. The mean +/- SD final bleb score was 5.4 +/- 0.3 in the group with releasable sutures compared with 4.2 +/- 0.6 in the group without releasable sutures (P<.001). The mean +/- SD final intraocular pressure at the end of 12 months was 16.9 +/- 1.2 mm Hg in the group without releasable sutures and 15.0 +/- 0.9 mm Hg in the group with releasable sutures (P<.001). Final intraocular pressure was controlled (intraocular pressure < or =21 mm Hg) in all patients in the group with releasable sutures, giving a success rate of 100%, and in 12 patients in the group without releasable sutures, giving a success rate of 80%. CONCLUSIONS: Use of releasable sutures is an effective way at no extra cost or instrumentation to maximize the long-term bleb score and lower intraocular pressure, and to minimize the short-term complications of trabeculectomy.     

Clinicopathological characteristics of skipping lymph node metastases in patients with colorectal cancer

We evaluated the optic disc in 77 eyes of 77 normal volunteers using a scanning laser tomograph (Heidelberg Retina Tomograph: HRT, version 1.11). Particular attention was paid to age, refractive error, and disc size. The topographic parameters included: cup area, C/D area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean RNFL thickness, and RNFL cross section area. There was a significant decline in mean RNFL thickness and RNFL cross section area with increase in age (p < 0.05). The mean and maximum cup depths were significantly deeper in myopic eyes (p < 0.05). Large discs had large values of cup area, C/D area ratio, rim area, cup volume, mean cup depth, cup shape measure (p < 0.01), and maximum cup depth (p < 0.05). Large discs had small values of mean RNFL thickness and RNFL cross section area. Rim volume was independent of age, refractive error, or disc area.     

Aging changes of the optic nerve head in relation to open angle glaucoma

AIMS: To determine the age related changes in optic nerve head structure in a group of normal subjects and assess the significance of any changes in relation to those found in open angle glaucoma. METHODS: A group of 88 white volunteers and friends and spouses of patients with a normal visual field and normal intraocular pressure was studied. Two different imaging and measurement devices were used (computer assisted planimetry and scanning laser ophthalmoscopy), and the results from each were compared. Measurements were made of the optic disc, optic cup, and neuroretinal rim areas, and the vertical optic disc diameter and cup/disc diameter ratio. RESULTS: Neuroretinal rim area declined at the rate of between 0.28% and 0.39% per year. Vertical optic cup diameter and optic cup area increased with age. The mean cup/disc diameter ratio increased by about 0.1 between the ages of 30 and 70 years. CONCLUSIONS: Age related changes are significant and measurable, and should be taken into account when assessing the glaucoma suspect, and when estimating the rate of progression of glaucomatous optic neuropathy in patients with established disease.     

Determination of the degree of stenosis of the internal carotid artery in the surgical specimen after eversion TEA: comparison with angiography and c-w-Doppler ultrasound

PURPOSE: To compare the ability of clinicians to detect change in the photographic appearance of the optic disk with the performance of a system for digitized image analysis. METHODS: In 11 monkey eyes, a Topcon Imagenet System was used to acquire eight digitized image pairs and four stereoscopic photographs at an intraocular pressure of 10 mm Hg, and then, again, 45 minutes after intraocular pressure was increased to 45 mm Hg. We recently reported detection of global (ten of 11 eyes) and regional (11 of 11 eyes) change in the digitized images of these eyes by using two new statistical strategies for optic disk analysis. For the current study, we evaluated the ability of three clinicians (the authors) to detect a change within the stereoscopic photographs of these 11 optic disks. For each eye, the eight stereoscopic photographs (four at intraocular pressure of 10 mm Hg and four at intraocular pressure of 45 mm Hg) were developed as stereoscopic slides and arranged into four pairs (10/10, 45/45, 10/45, and 45/10 mm Hg). Thus, two pairs represented no change in intraocular pressure (10/10 and 45/45 mm Hg) and the other two pairs represented either an increase or a decrease in intraocular pressure (10/45 and 45/10 mm Hg). The 44 pairs of stereoscopic slides (four pairs for each of 11 eyes) were masked then randomly mixed. On two separate occasions, each clinician evaluated each pair of stereoscopic slides for the presence of absence of optic disk change. RESULTS: Reproducibility between the two readings of each clinician ranged from .50 to .64 (kappa statistic). Clinicians correctly detected change (as detected by image analysis) within 45% to 64% of the 10/45 and 45/10 pairs of stereoscopic slides. Clinicians correctly indentified no change within 86% to 100% of the 10/10- and 45/45-mm Hg pairs of stereoscopic slides. Clinicians correctly identified no change significantly more often than change (P < .01, chi 2 test). Change was not detected consistently by all three clinicians in any of the 11 eyes. CONCLUSION: In a controlled experimental setting, digitized image acquisition with extensive secondary statistical analysis more sensitively detected small short-term changes in the surface of the optic disks of monkeys than did three masked clinicians.     

Determination of long-life radiocesiums Cs-134 and Cs-137 in food by gamma-ray spectrometry: summary of collaborative study

PURPOSE: The authors evaluated the ability of a confocal scanning laser ophthalmoscope to detect glaucomatous visual field loss by using their previously described discriminant formula on a prospectively obtained cohort. The relationship of optic disc size to diagnostic classification was also evaluated. METHODS: One eye was chosen randomly from each of 153 subjects. Sixty control eyes had intraocular pressure less than 21 mmHg and normal visual fields; 93 glaucomatous eyes had intraocular pressure greater than 21 mmHg and abnormal visual fields. The optic disc status purposely was not used for classification purposes. All subjects were examined with the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering GMBH, Heidelberg, Germany) and Humphrey Perimeter, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA). Visual fields were considered abnormal by the authors' previously published criteria. The HRT classification used age, adjusted cup shape measure, rim volume, and height variation contour to classify the optic disc as normal or glaucomatous. Then the authors assessed the sensitivity, specificity, and diagnostic precision for the entire group, and for three subsets classified by disc area: disc area less than 2 mm2, between 2 and 3 mm2, and more than 3 mm2. RESULTS: The entire group had a sensitivity, specificity, and diagnostic precision of 74%, 88%, and 80%, respectively. The specificity was 83% when disc area was less than 2 mm2 and improved to 89% when disc area was more than 2 mm2. The sensitivity tended to improve from 65% to 79%, and to 83% if the disc area increased, but the difference was not statistically significant. CONCLUSIONS: In a prospective cohort of patients, the HRT discriminant analysis formula was capable of detecting glaucomatous visual field loss with good precision. Unusually small optic discs continue to present diagnostic difficulties.     

Effect of local administration of mitomycin C on intraocular pressure

BACKGROUND: Animal studies suggest that the decrease of intraocular pressure after application of mitomycin C is particularly mediated by toxic effects on the substance of ciliary body. Moreover it has been shown that the concentration of mitomycin C after topical application in the aqueous humour is as high when performing fistulating surgery. In this prospective study we wanted to investigate whether the topical application of mitomycin C would result in a significant decrease of intraocular pressure. PATIENTS AND METHODS: Forty-one eyes of 41 patients underwent pterygium surgery using a bare sclera technique. Afterwards phototherapeutic keratectomy with the excimer laser (193 nm) was performed in the area of the excision. In hospital mitomycin C eye drops (0.02%) were given twice daily for four days. The intraocular pressure of treated and untreated eyes was measured with applanation tonometry at least three times per day preoperatively, postoperatively at the fourteenth day and after 6 month. RESULTS: Mean intraocular pressure of the treated eyes was preoperatively 15.73 +/- 2.35 mm Hg, 14 days postoperatively 15.92 +/- 2.79 mm Hg and at the last examination 15.86 +/- 2.39 mm Hg. For untreated eyes the mean intraocular pressure was preoperatively 15.70 +/- 2.04 mm Hg, after 14 days 15.76 +/- 2.96 mm Hg and at the last examination 15.89 +/- 2.67 mm Hg. Consequently there was no statistically significant change of intraocular pressure in the eyes treated with mitomycin C. Furthermore there were no significant differences of intraocular pressure between treated and untreated eyes at any time of postoperative check-up. CONCLUSION: The short-term local application of mitomycin C did not result in a detectable change of intraocular pressure and is therefore probably an alternative to intraoperative application during filtration surgery.     

Influence of optic disc size on the sensitivity of the Heidelberg Retina Tomograph

PURPOSE: The aim of this study was to evaluate the influence of optic disc size on the ability of variables generated by the Heidelberg Retina Tomograph, software version 1.11, to distinguish glaucoma patients from normals in a cross-sectional study. PATIENTS AND METHODS: For evaluation of the optic disc with the Heidelberg Retina Tomograph, eyes of 87 normals and 61 glaucoma patients were selected. Disc area, volume above reference, rim area, cup area, cup volume, third moment in contour and the mean retinal nerve fibre layer thickness at the border of the optic disc were selected for evaluation. The sensitivity at 80% specificity of these variables was calculated under three conditions: (1) no correction for disc size; (2) calculation in the following disc size ranges: class I (1.0-2.0 mm2), class II (2.0-2.5 mm2), class III (2.5-3.15 mm2) and class IV (3.15-5.0 mm2); (3) calculation globally, taking into account the different disc sizes of the four classes. RESULTS: Neuroretinal rim area, cup area and volume, third moment and nerve fibre layer thickness were significantly and positively correlated with optic disc size in normals. Neuroretinal rim volume measurements were statistically independent of optic disc size. Sensitivity was lowest when the size of the optic disc was not considered. Sensitivity increased when evaluated in four optic disc size classes. With growing optic disc size sensitivity of the retinal nerve fibre layer increased and third moment value decreased. Cup volume and area had their lowest sensitivity for large optic discs. The area of the neuroretinal rim was the only variable which showed similar sensitivity values under all three conditions. CONCLUSIONS: The sensitivities of HRT variables varied with optic disc size. Evaluation of their sensitivity requires the definition of optic disc classes or statistical correction for the size of the optic disc.     

Prosthetic arteriovenous fistulas and venous anastomotic stenosis: influence of a high flow velocity on the development of intimal hyperplasia

OBJECTIVE: To search a sensitive parameter for the early diagnosis of primary open angle glaucoma (POAG). METHOD: A system of computerized image analysis was used to acquire images of the optic nerve head of patients with POAG, suspect glaucoma (SG) and of normal persons. Each of these groups contained 31 eyes of 31 cases. The mean relative depths of disc rim and cup at different areas in the optic nerve head were measured. All these patients were followed up for four to six months, and the changes of the mean depths of every sector were compared between each pair of the three groups with statistic analysis. RESULTS: The mean depth of the neural rim and cup of each sector and that of total rim and total cup of POAG and SG patients were all deeper than that of normal controls. The mean depths of neural rim of the superior sector, inferior sector and the total rim area of POAG were deeper than that of SG patients. Compared to their first measurements, the changes of mean depths of neural rim of superior sector and total neural rim area of POAG patients were more prominent than that of normal controls and SG. We also compared the relative depth of the total rim area in the different areas in the optic nerve head with other two dimensional optic disc parameters such as cup/disc ratio, etc. CONCLUSION: Our study suggests that three-dimensional stereoscopic measurement of the surface of optic nerve head and follow-up be of paramount importance in the early diagnosis of POAG patients.     

The Chiropractic Outcome Study: pain, functional ability and satisfaction with care

BACKGROUND: Elevation of intraocular pressure in the supine position has been previously described in literature. Aim of this study is to investigate the elevation of intraocular pressure in normal tension glaucoma and its effect on the morphology of the optic disc, visual field function and capillary blood flow of the retina and optic disc. PATIENTS AND METHODS: 56 eyes of 28 preperimetric and advanced normal tension glaucoma patients were prospectively evaluated. Ten eyes of ten normal patients served as a control group for the measurements of the intraocular pressure. In the course of a 24-h pressure profile applanation tonometry was performed in the morning in a supine and three and ten minutes later in a sitting position with Draeger's and Goldmann's tonometers. Arterial blood pressure was measured at the same time. The optic disc's morphology was evaluated by stereo photographs and Laser Scanning Tomography. As a sensory test computer perimetry was used. Capillary blood flow was measured at defined areas of the retina and optic disc. An intraocular pressure above 21 mm Hg in the supine position was used as a criterium to define two groups of normal tension glaucoma patients. RESULTS: In the supine position a statistically significant elevation of intraocular pressure was observed in 24 normal tension glaucoma patients by 6.2 +/- 2.8 mm Hg up to 21.8 +/- 3 mm Hg. Diastolic blood pressure in the supine position (80 +/- 10.5 mm Hg) was significantly lower than in the sitting position (94 +/- 11 mm Hg, p = 0.021). 12 of 28 normal tension glaucoma patients showed an intraocular pressure lower than 22 mm Hg in the supine position. In these patients a tendency towards a higher incidence for the occurrence of optic disc haemorrhages and significantly higher values for blood flow (p < 0.0005) and volume (p < 0.005) in the retina and optic nerve head could be shown. In this group of normal pressure glaucoma patients a higher incidence of migraine and vasospastic complaints was reported in the patients' history. CONCLUSION: In this study some normal tension glaucoma patients showed intraocular pressures in the supine position higher than 21 mm Hg and a lower diastolic arterial pressure. The higher incidence of haemorrhages and higher values for flow and volume parameters of the optic disc in normal tension glaucoma patients with an intraocular pressure lower than 22 mm Hg implicate the existence of two entities: real and pseudo normal tension glaucomas.     

Fornix-based trabeculectomy with mitomycin-C

BACKGROUND AND OBJECTIVE: Mitomycin-C (MMC) has been shown to improve the surgical success of trabeculectomy; however, the advantages of MMC have been evaluated almost entirely as an adjunct to limbal-based trabeculectomy. This study evaluated the efficacy and safety of fornix-based trabeculectomy with MMC for glaucomatous patients. PATIENTS AND METHODS: Between January 1993 and April 1995, 71 patients underwent fornix-based trabeculectomy with topical application of 0.4 mg/ml of MMC for 3 minutes. The conjunctiva-Tenon's capsule flap was spread over the limbus and sutured in order to create a visible crease with a water-tight closure. The mean follow-up time was 14.5 months. RESULTS: The mean intraocular pressure (IOP) before surgery was 32.4 +/- 9.7 mm Hg. The average postoperative IOP was 14.04 +/- 9.57 mm Hg. An IOP of 20 mm Hg or less was observed in 57 eyes (80%). Postoperatively, 37 eyes (52%) required no additional medical therapy. One month after surgery, only 2 patients had wound leakage with hypotony and choroidal detachment. Two eyes (3%) had suprachoroidal hemorrhage with loss of vision. A conjunctival "buttonhole" occurred in 2 eyes (3%), but only 1 persisted more than a month. CONCLUSIONS: Fornix-based trabeculectomy using intraoperative application of 0.4 mg/ml of MMC for 3 minutes was found to be as safe and effective as limbal-based trabeculectomy with MMC.     

Reduction in number of corpora amylacea with advancing histological changes of glaucoma

Retina and optic nerve of eyes enucleated due to an iris ring melanoma or a malignant melanoma of the ciliary body were studied to investigate the correlation between corpora amylacea count and glaucoma stages. Ten eyes from ten patients [age: 62.3 +/- 13.0 (mean +/- SD); range 43-84 years] were used for the present study. Eight eyes had shown elevated intraocular pressure readings preoperatively. The corpora amylacea count was correlated with histomorphometric changes of the intra- and parapapillary region. The corpora amylacea count of the retinal ganglion cells decreased significantly with increased histological ratio of cup to disc, decreased retinal nerve fiber layer thickness, and increased optic cup depth. There was no significant correlation between the corpora amylacea count of the bipolar cells and each histomorphometric datum. These results suggest that the corpora amylacea of the retinal ganglion cells decrease in number with advancing histological changes of secondary glaucoma.     

The effect of hyperthermia on aqueous humor dynamics in rabbits

Hyperthermia increased intraocular pressure (Po) by approximately 5 mm Hg in rabbit eyes. This increase was not associated with changes in plasma osmolarity, blood lactate, or pH. Episcleral venous pressure (Pv) decreased from a baseline of 11 +/- 1 mm Hg(mean +/- SEM) to 8 +/- 1 mm Hg after one hour of hyperthermia. Outflow facility (c) as measured by tonography remained unchanged. Aqueous humor flow [c(Po - Pv)] as estimated by tonography increased by about 126%. The elevation of intraocular pressure was not prevented by aspirin pretreatment nor altered by unilateral optic nerve transection.     

Endophthalmitis after filtering surgery with mitomycin

OBJECTIVE: To identify the incidence, causative organisms, and clinical outcomes of eyes with bleb-associated endophthalmitis after glaucoma filtering procedures with adjunctive mitomycin. METHODS: Retrospective analysis of 773 consecutive eyes that underwent glaucoma filtering surgery at the Bascom Palmer Eye Institute, Miami, Fla. The course of 609 eyes from 485 patients with a minimum of 3 months of follow-up were reviewed. RESULTS: Mean follow-up was 16.0 +/- 11.5 months (range, 3-48 months). Of the 609 eyes, 13 (2.1%) developed bleb-associated endophthalmitis an average of 18.5 +/- 13.2 months after surgery (range, 1-45 months). The incidence of bleb-associated endophthalmitis was significantly greater after inferior trabeculectomy (7.8% per patient-year) than after superior trabeculectomy (1.3% per patient-year) by Kaplan-Meier estimates (P = .02, log rank test). The cumulative incidence was 13% for inferior limbal blebs and 1.6% for superior limbal blebs. Nine (69.2%) of the 13 eyes were culture positive. Streptococcus sanguis and Haemophilus influenzae (6/13 [46.2%]) were the most frequent causative organisms. The mean increase in intraocular pressure after endophthalmitis treatment was 1.2 mm Hg, with a mean decrease in visual acuity of 1.42 logMAR units. Eight (61.5%) of the 13 eyes had a final acuity of 20/400 or better. CONCLUSIONS: The incidence of bleb-associated endophthalmitis after guarded filtering surgery performed with adjunctive mitomycin is higher than the reported rate in eyes undergoing filtering surgery without the use of antifibrotic agents (0.2%-1.5%). Inferior limbal trabeculectomy carries the highest risk of infection. Eyes with mitomycin blebs maintained excellent filtration capacity. However, after treatment of the infection, the visual outcomes were generally poor.     

PDGF and TGF-beta induce cell shape changes in invertebrate immunocytes via specific cell surface receptors

BACKGROUND: To compare neuroretinal rim area measurements by confocal scanning laser tomography and planimetric evaluation of optic disc photographs. METHODS: For 221 patients with primary and secondary open angle glaucoma, 72 subjects with ocular hypertension, and 139 normal subjects, the optic disc was morphometrically analysed by the confocal scanning laser tomograph HRT (Heidelberg retina tomograph) and by planimetric evaluation of stereo colour optic disc photographs. RESULTS: Absolute rim area and rim to disc area were significantly (p < 0.0001) larger with the HRT than with planimetric evaluation of photographs. Differences between the two methods were significantly (p < 0.01) larger in normal eyes with small cupping than in normal eyes with large cupping, and differences were significantly (p < 0.01) larger in glaucomatous eyes with marked nerve damage than in glaucomatous eyes with moderate nerve damage. Coefficients of correlations between rim measurements of both methods were R2 = 0.60 for rim to disc area and R2 = 0.33 for absolute rim area. Planimetric measurements of rim area correlated significantly (p < 0.05) better than HRT determinations of rim area with mean visual field defect and retinal nerve fibre layer visibility. CONCLUSIONS: Measurements of absolute rim area and rim to disc area are significantly larger with the HRT compared with planimetry of disc photographs. Differences between both methods depend on disc area, cup size and glaucoma stage. The reason may be that the HRT measures the retinal vessel trunk as part of the neuroretinal rim. The differences between both methods, which should be taken into account if disc measurements performed by both methods are compared with each other, may not influence the main advantage of the HRT--that is, morphological follow up examination of patients with glaucoma.     

Analysis of depressive symptomatology in mood disorders

BACKGROUND: At this time little information is available about the relationship between glaucomatous visual field defects and impaired blood flow in the optic nerve head. The purpose of this study was to examine blood flow of the juxtapapillary retina and the rim area of the optic nerve head in primary open-angle glaucoma with a borderline visual defect. METHODS: Juxtapapillary retinal and neuroretinal rim area blood flow was measured by scanning laser Doppler flowmetry (SLDF). The visual field was evaluated by static perimetry (Octopus-G1). The optic nerve head was assessed on 15 degrees color stereo photographs. We examined 116 eyes of 91 patients with POAG with controlled IOP and 66 eyes of 44 healthy individuals. The POAG group was divided into eyes with a mean defect lower than 2 dB (POAG group I) and in eyes with a mean defect equal to or greater than 2 dB (POAG group II). The mean age of POAG group I and POAG group II was 55 +/- 11 years and 57 +/- 10 years, respectively. The mean age of the control group was 45 +/- 15 years. The eyes of POAG group I had an average C/D ratio of 0.71 +/- 0.18 with an average mean defect of the visual field of 0.97 +/- 0.68 dB; the eyes of POAG group II had an average C/D ratio of 0.80 +/- 0.17 with an average mean defect of the visual field of 8.2 +/- 6.0 dB. The intraocular pressure on the day of measurement in POAG group I was 18.2 +/- 3.7 mmHg, in POAG group II 17.6 +/- 4.0 mmHg, and in the control group 15.1 +/- 2.5 mmHg. For statistical analysis, age-matched groups of 32 normal eyes of 32 subjects (mean age 52 +/- 10 years) were compared to 18 glaucomatous eyes of 18 patients (POAG group I, mean age 55 +/- 11 years) and 59 glaucomatous eyes of 59 patients (POAG group II, mean age 55 +/- 10 years). RESULTS: In the eyes of POAG group I and POAG group II, both juxtapapillary retinal blood flow and neuroretinal rim area blood flow were significantly decreased compared to an age-matched control group: neuroretinal rim area "flow" POAG group I -65%, POAG group II -66%; juxtapapillary retina "flow" POAG group I -52%, POAG group II -44%. All eyes of the POAG group I (MD < 2 dB) and 56 of 61 eyes of the POAG group II (MD > = 2 dB) showed a retinal perfusion lower than the 90% percentile of normal blood flow. We found no correlation between reduction of juxtapapillary or papillary blood flow and mean defect in POAG eyes. CONCLUSION: Glaucomatous eyes with no defects or borderline visual field defects as well as glaucomatous eyes in an advanced disease stage show significantly decreased optic nerve head and juxtapapillary retinal capillary blood flow.     

The bait in the Rubisco mousetrap

The authors present an account on their first results of trabeculectomy with releasable sutures, as described by Osher. The intraocular pressure before operation was on average 21.7 mm Hg (23-40 mm Hg). During the last visit (on average 2.8 months after operation) it was 13.5 mm Hg (13-15 mm Hg), incl. six eyes without treatment. Only in two eyes during the early postoperative period a shallower anterior chamber was observed. The authors recommend more extensive use of the technique of releasable suture in trabeculectomy.     

Impact of antibiotic resistance on chemotherapy for pneumococcal infections

PURPOSE: To detect the mechanism of intraocular pressure elevation during hemodialysis. METHODS: We measured intraocular pressure, as well as serum osmolality and plasma CO2 pressure, every 30 min during hemodialysis, in 5 eyes with severely compromised aqueous outflow facility (Group A) from 4 renal failure patients. The same measurements were repeated on the same eyes using intravenous hyperosmotic Glyceol to prevent a rapid change in serum osmolality. We also measured the same parameters on 8 eyes with normal aqueous outflow facility (Group B) from 5 patients. The mean +/- SE of percent changes in each parameter was used for the statistical analysis. RESULTS: In Group A, the mean percent change of intraocular pressure increased significantly after 90 min, with the exception of the change at 180 min. The mean percent change of serum osmolality decreased significantly after starting dialysis. A negative correlation in the mean percent change of intraocular pressure with serum osmolality was detected (r = -0.759, r < 0.0001). The administration of intravenous hyperosmotic agent prevented significant changes in not only serum osmolality but also intraocular pressure. In Group B, the mean percent change in intraocular pressure showed no significant difference at any time, although the change in serum osmolality decreased significantly. CONCLUSION: A remarkable rise in intraocular pressure occurs during hemodialysis in eyes with an impaired aqueous outflow, when serum osmolality decreases rapidly.     

Unilateral testing of utricular function

PURPOSE: To examine acquired pit of the optic nerve as a risk factor for progression of glaucoma. METHODS: In a retrospective longitudinal study, 25 open-angle glaucoma patients with acquired pit of the optic nerve were compared with a group of 24 open-angle glaucoma patients without acquired pit of the optic nerve. The patients were matched for age, mean intraocular pressure, baseline ratio of neuroretinal rim area to disk area, visual field damage, and duration of follow-up. Serial optic disk photographs and visual fields of both groups were evaluated by three independent observers for glaucomatous progression. RESULTS: Of 46 acquired pits of the optic nerve in 37 eyes of 25 patients, 36 pits were located inferiorly (76%) and 11 superiorly (24%; P < .001). Progression of optic disk damage occurred in 16 patients (64%) in the group with acquired pit and in three patients (12.5%) in the group without acquired pit (P < .001). Progression of visual field loss occurred in 14 patients (56%) in the group with acquired pit and in six (25%) in the group without pit (P=.04). Bilateral acquired pit of the optic nerve was present in 12 patients (48%). Disk hemorrhages were observed more frequently in the group with acquired pit (10 eyes, 40%) compared with the group without pit (two eyes, 8%; P=.02). CONCLUSION: Among patients with glaucoma, patients with acquired pit of the optic nerve represent a subgroup who are at increased risk for progressive optic disk damage and visual field loss.