Trabeculectomy training in England: are we safe at training? Two year surgical outcomes.

OBJECTIVES: To define the safety profile of trainee trabeculectomy surgery in the United Kingdom. Surgical exposure for trainees in England is limited due to service requirements, the European working time directive constraints and increasing sub-specialisation of glaucoma surgery. Limited knowledge exists on the outcomes of supervised glaucoma surgery. The aim is to determine the safety of supervised trabeculectomy surgery performed by trainee ophthalmologists. METHODS: Retrospective case note review of all patients that had trabeculectomy surgery with MMC by consultant and trainee surgeons across multiple UK centres. All eyes have 2-year follow up. Success was determined using WGA guidelines. Two-tailed p values were obtained using Fisher's exact test to ascertain statistical significance between groups. MAIN OUTCOME MEASURES: intraocular pressure, visual acuity, success and failure rates. RESULTS: 324 eyes were reviewed. 211 (66.4%) cases were performed by glaucoma consultants, 107(33.6%) by trainee ophthalmologists. The majority of eyes in each group were undergoing surgery for POAG. Post-operative IOP control showed no significant difference between consultant and trainee groups at year 1 and year 2. Success rates showed no significant difference between consultant and trainee cases. Failure rates at year 1 showed a significant difference between the two groups. No significant difference was seen at year 2. The trainee group had significantly more complications, when compared with the consultant group. Snellen visual acuity loss was not statistically significant between the two groups at the 2 year time point. CONCLUSIONS: The outcomes of supervised trainee trabeculectomy compare favourably with consultant cases after 2 year follow up. Trainee cases had higher complication rates than consultant cases. Bleb leaks are a common complication of trainee cases, where closer supervision may be required. There is potential for surgical simulation to help increase the success of such cases. These findings may encourage trainee participation in glaucoma surgery.

In vivo oximetry of human bulbar conjunctival and episcleral microvasculature using snapshot multispectral imaging.

Multispectral imaging (MSI) is a well-established technique for non-invasive oximetry of retinal blood vessels, which has contributed to the understanding of a variety of retinal conditions, including glaucoma, diabetes, vessel occlusion, and retinal auto-regulation. We report the first study to use snapshot multi-spectral imaging (SMSI) for oximetry of the bulbar conjunctival and episcleral microvasculature in the anterior segment of the eye. We report the oxygen dynamics of the bulbar conjunctival and episcleral microvasculature at normoxia and at acute mild hypoxia conditions. A retinal-fundus camera fitted with a custom Image-Replicating Imaging Spectrometer was used to image the bulbar conjunctival and episcleral microvasculature in ten healthy human subjects at normoxia (21% Fraction of Inspired Oxygen [FiO2]) and acute mild hypoxia (15% FiO2) conditions. Eyelid closure was used to control oxygen diffusion between ambient air and the sclera surface. Four subjects were imaged for 30 seconds immediately following eyelid opening. Vessel diameter and Optical Density Ratio (ODR: a direct proxy for oxygen saturation) of vessels was computed automatically. Oximetry capability was validated using a simple phantom that mimicked the scleral vasculature. Acute mild hypoxia resulted in a decrease in blood oxygen saturation (SO2) (i.e. an increase in ODR) when compared with normoxia in both bulbar conjunctival (p < 0.001) and episcleral vessels (p = 0.03). Average episcleral diameter increased from 78.9 ± 8.7 µm (mean ± standard deviation) at normoxia to 97.6 ± 14.3 µm at hypoxia (p = 0.02). Diameters of bulbar conjunctival vessels showed no significant change from 80.1 ± 7.6 µm at normoxia to 80.6 ± 7.0 µm at hypoxia (p = 0.89). When exposed to ambient air, hypoxic bulbar conjunctival vessels rapidly reoxygenated due to oxygen diffusion from ambient air. Reoxygenation occured in an exponential manner, and SO2 reached normoxia baseline levels. The average ½ time to full reoxygenation was 3.4 ± 1.4 s. As a consequence of oxygen diffusion, bulbar conjunctival vessels will be highly oxygenated (i.e. close to 100% SO2) when exposed to ambient air. Episcleral vessels were not observed to undergo any significant oxygen diffusion, instead behaving similarly to pulse oximetry measurements. This is the first study to the image oxygen dynamics of bulbar conjunctival and episcleral microvasculature, and consequently, the first study to directly observe the rapid reoxygenation of hypoxic bulbar conjunctival vessels when exposed to ambient air. Oximetry of bulbar conjunctival vessels could potentially provide insight into conditions where oxygen dynamics of the microvasculature are not fully understood, such as diabetes, sickle-cell diseases, and dry-eye syndrome. Oximetry in the bulbar conjunctival and episcleral microvasculature could be complimentary or alternative to retinal oximetry.

Oxygen saturation measurements of the retinal vasculature in treated asymmetrical primary open-angle glaucoma using hyperspectral imaging.

PURPOSE: To determine whether there are differences in retinal vascular oxygen saturation measurements, estimated using a hyperspectral fundus camera, between normal eyes and treated eyes of subjects with asymmetrical primary open-angle glaucoma (POAG). METHODS: A noninvasive hyperspectral fundus camera was used to acquire spectral images of the retina at wavelengths between 556 and 650 nm in 2-nm increments. In total, 14 normal eyes and both eyes of 11 treated POAG subjects were imaged and analyzed using algorithms that use the spectral variation of the optical densities of blood vessels to estimate the oxygen saturation of blood within the retinal vasculature. In the treated POAG group, each of the eyes were categorized, based on the mean deviation of the Humphrey visual-field analyzer result, as either more-advanced or less-advanced, glaucomatous eyes. Unpaired t-tests (two-tailed) with Welch's correction were used to compare the mean oxygen saturation between the normal subjects and the treated POAG subgroups. RESULTS: In less-advanced and more-advanced-treated POAG eyes, mean retinal venular oxygen saturations (48.2±21.6% and 42.6±18.8%, respectively) were significantly higher than in normal eyes (27.9±9.9%; P=0.03 and 0.01, respectively). Arteriolar oxygen saturation was not significantly different between normal eyes and treated POAG eyes. CONCLUSIONS: The increased oxygen saturation of the retinal venules in advanced-treated POAG eyes may indicate reduced metabolic consumption of oxygen in the inner retinal tissues.

Portsmouth visual field database: an audit of glaucoma progression.

AIM: To explore visual field (VF) progression in a cohort of secondary care-treated glaucoma and ocular hypertensive (OHT) patients. METHODS: We extracted VFs from our database drawn from our normal clinical practice. VF series from 4177 eyes from 2208 patients who had five or more VFs were obtained, the 'better' eye was selected and the rate of VF progression was calculated using mean deviation (MD) data. RESULTS: The median rate of progression for the whole sample was -0.1 dB/year (interquartile range (IQR) -4 to 0 dB/year) over a median of 6.7 years (IQR 4.9-8.7). Of 2208 patients, 477 (21.2%) progressed at > -0.5 dB/year; 46 (2.1%) progressed at >-2.0 dB/year. Of those with a 'final MD' of worse than -10 dB (N=244) in their better eye; 14.0% were 'fast progressors' (>-2 dB/year), 33.7% 'moderate progressors' (-1 to -2 dB/year), and 28.8% 'slow progressors' (-0.3 dB to -1 dB/year). Of those with 'initial MD' better than -3 dB and those with worse than -3 dB, 31/1679 (1.8%) and 213/529 (40.3%) respectively, had a final MD of worse than -10 dB. CONCLUSION: Fast progressors, while important, are relatively rare. Moderate and slow progressors make up the majority of the progressing population within this data set. The risk of significant visual loss is much higher in those with initial damage. With increasing life expectancy, moderate and slow progressors may become increasingly clinically important.

Spectral imaging of the retina.

INTRODUCTION: The work described here involved the use of a modified fundus camera to obtain sequential hyperspectral images of the retina in 14 normal volunteers and in 1 illustrative patient with a retinal vascular occlusion. METHODS: The paper describes analysis techniques, which allow oximetry within retinal vessels; these results are presented as retinal oximetry maps. RESULTS: Using spectral images, with wavelengths between 556 and 650 nm, the mean oxygen saturation (OS) value in temporal retinal arterioles in normal volunteers was 104.3 (± 16.7), and in normal temporal retinal venules was 34.8 (± 17.8). These values are comparable to those quoted in the literature, although, the venular saturations are slightly lower than those values found by other authors; explanations are offered for these differences. DISCUSSION: The described imaging and analysis techniques produce a clinically useful map of retinal oximetric values. The results from normal volunteers and from one illustrative patient are presented. Further developments, including the recent development of a 'snapshot' spectral camera, promises enhanced non-invasive retinal vessel oximetry mapping.

Ultrasound reduces the minimum effective local anaesthetic volume compared with peripheral nerve stimulation for interscalene block.

BACKGROUND: Previous studies have demonstrated that lower local anaesthetic (LA) volumes can be used for ultrasound (US)-guided interscalene brachial plexus block (ISB). However, no study has examined whether US can reduce the volume required when compared with nerve stimulation (NS) for ISB. Our aim was to do this by comparing the minimum effective analgesic volumes (MEAVs). METHODS: After ethics approval and informed consent, patients undergoing shoulder surgery were recruited to this randomized, double-blind, up-down sequential allocation study. The volume used for both US and NS was dependent upon the success or failure of the previous block. Success was defined as a verbal rating score of 0/10, 30 min after surgery. Ten needle passes were allowed before defaulting to the opposite group. Patients received general anaesthesia. Pain scores and analgesic consumption were assessed by a blinded observer. Statistical comparisons of continuous variables were performed using Student's t-test and Mann-Whitney U-test as appropriate. Categorical variables were analysed using χ² test. MEAV values were estimated using log-transformed up-down independent pairs analysis and probit regression. Significance was assumed at P<0.05 (two-sided). RESULTS: The MEAV required to provide effective analgesia was significantly (P=0.034) reduced to 0.9 ml [95% confidence interval (CI) 0.3-2.8] in the US group from 5.4 ml (95% CI 3.4-8.6) in the NS group. Fewer needle passes were needed to identify the brachial plexus with US (1 vs 3; P<0.0001) and patients had less pain at 30 min after surgery (P=0.03). CONCLUSIONS: US reduces the number of attempts, LA volume, and postoperative pain when compared with NS for ISB.

A hybrid tool for reaching and grasping rehabilitation: the ArmeoFES.

Many research groups are currently working with robotic devices for hand grasp rehabilitation and restoration. A common problem in this area is the fact that existing and commercially available robotic exoskeletons are able to provide gravity compensation of the shoulder and elbow but do not provide any support for the grasping and releasing movements of the hand. The lack of a flexible support technology for the hand reduces the possible ways in which clinicians can deal with the issue of a personalized, effective rehabilitation. This paper presents new software that allows FES assisted grasping to integrate with the ArmeoSpring (Hocoma AG). The system uses a Man-In-The-Loop control approach, whereby surface EMG signals from proximal muscles are used to trigger and modulate multichannel FES applied to distal muscles, thus allowing patient induced and strength adapted movement control of the hand. Combining volitionally controlled FES with arm-weight-compensation allows early adoption of FES assisted therapy for patients, augmenting their functionalities and extending training capabilities with the ArmeoSpring.

Experimental data checker: better information for organic chemists.

An experimental data checker has been developed that reads, analyses, and cross-correlates experimental information copied and pasted from authors' manuscripts, which will be useful for authors, referees, editors and readers of papers reporting new molecular information, and which makes possible a quantification of the accuracy of journals' data.

Interobserver agreement on visual field progression in glaucoma: a comparison of methods.

AIM: To examine the level of agreement between clinicians in assessing progressive deterioration in visual field series using two different methods of analysis. METHODS: Each visual field series satisfied the following criteria: more than 19 reliable fields, patient age over 40 years, macular threshold at least 30 dB. The first three fields in each series were excluded to minimise learning effects: the following 16 were studied. Five expert clinicians assessed the progression status of each series using both standard Humphrey printouts and pointwise linear regression (PROGRESSOR). The level of agreement between the clinicians was evaluated using a weighted kappa statistic. RESULTS: A total of 432 tests comprising 27 visual field series of 16 tests each were assessed by the clinicians. The level of agreement on progression status between the clinicians was always higher when they used PROGRESSOR (median kappa = 0.59) than when they used Humphrey printouts (median kappa = 0.32). This was statistically significant (p = 0.006, Wilcoxon matched pairs signed rank sum test). CONCLUSIONS: Agreement between expert clinicians about visual field progression status is poor when standard Humphrey printouts are used, even when the field series studied are long and consist solely of reliable fields. Under these ideal conditions, clinicians agree more closely about patients' visual field progression status when using PROGRESSOR than when inspecting series of Humphrey printouts.

Evidence for genetic heterogeneity within eight glaucoma families, with the GLC1A Gln368STOP mutation being an important phenotypic modifier.

OBJECTIVE: To investigate the phenotype and age-related penetrance of primary open-angle glaucoma (POAG) in Australian families with the most common Myocilin mutation (Gln368STOP). DESIGN: Cross-sectional genetic study. PARTICIPANTS: Eight pedigrees carrying the Gln368STOP mutation were ascertained from 1730 consecutive cases of POAG in the Glaucoma Inheritance Study in Tasmania. METHODS: Index cases and available family members were examined for signs of glaucoma, and the presence of the GLC1A Gln368STOP mutation was ascertained by single-strand conformation polymorphism analysis and subsequent direct sequencing. RESULTS: From the eight pedigrees, 29 Gln368STOP mutation-carrying individuals with either ocular hypertension (OHT) or POAG were found, with a mean age at diagnosis of 52.4 +/- 12.9 years and a mean peak intraocular pressure (IOP) of 28.4 +/- 4.7 mmHg. A further 11 mutation carriers older than 40 years have been studied, who as yet show no signs of OHT or POAG. Within the 8 pedigrees, a further 31 individuals with OHT or POAG were identified who did not carry the Gln368STOP mutation. For these individuals the mean age at diagnosis was higher (62.3 +/- 13.7 years, P < 0.01), and the mean peak IOP was lower (25.4 +/- 6.4 mmHg, P = 0.01). For Gln368STOP carriers, age-related penetrance for OHT or POAG was 72% at age 40 years and 82% at age 65 years. A positive family history of POAG was present in all index cases. Five of the eight pedigrees had a positive family history on both maternal and paternal sides. Seven of the eight pedigrees had one or more individuals with POAG who did not carry the mutation. Eight of the 29 Gln368STOP carriers with OHT or POAG had undergone trabeculectomy. CONCLUSIONS: The GLC1A Gln368STOP mutation is associated with POAG, which in the pedigrees studied is of a younger age of onset and higher peak IOP than non-mutation glaucoma cases. In addition, Gln368STOP mutation glaucoma cases were more likely to have undergone glaucoma drainage surgery. We have not observed simple autosomal dominant inheritance patterns for POAG in these pedigrees. Other factors, as yet uncharacterized, are involved in expression of the POAG phenotype in Gln368STOP pedigrees.

Accuracy and implications of a reported family history of glaucoma: experience from the Glaucoma Inheritance Study in Tasmania.

OBJECTIVES: To ascertain the prevalence of previously undiagnosed primary open-angle glaucoma (POAG) within 5 large POAG pedigrees and to evaluate the reliability of a reported family history of glaucoma within these pedigrees. METHODS: The Glaucoma Inheritance Study in Tasmania (GIST) identified several large adult POAG pedigrees. Intraocular pressure (IOP), optic disc stereophotography, and automated perimetry were performed on all adult pedigree members. Participants were classified as normal (IOP <22 mm Hg and normal optic disc and field); glaucoma suspect (normal field, but an IOP >/=22 mm Hg and/or suspicious optic disc); or POAG (field defect and glaucomatous optic disc). Some individuals with POAG had been previously diagnosed by their local ophthalmologist; others were diagnosed as a result of the GIST project. Family members with a prior diagnosis of POAG were asked to report if they were aware of any relatives with POAG. This reported family history was then directly compared with the actual pedigree (before the diagnosis of new cases) to calculate agreement. MAIN OUTCOME MEASURE: The rate of glaucoma in pedigrees and percentage of previously diagnosed glaucoma cases who were aware of the positive family history of POAG. RESULTS: Four hundred forty-two subjects (mean age, 54 years [range, 13-97 years]) from 5 pedigrees were examined: 316 subjects (71%) were normal, 47 (11%) were previously diagnosed with POAG, and 8 (2%) were previously diagnosed glaucoma suspects; 30 cases (7%) of POAG and 41 suspects (9%) were newly diagnosed as a direct result of the GIST examination. Of the 47 previously diagnosed POAG cases, 41 were questioned about their prior knowledge of any family history and 11 (27%) were unaware of their family history of POAG. CONCLUSIONS: Examination of all adult subjects from POAG families yields new cases. Even in large POAG pedigrees, 27% of previously diagnosed POAG patients were unaware of their positive family history. These findings suggest that a higher percentage of adult POAG may be inherited than hitherto reported. Arch Ophthalmol. 2000;118:900-904

Theoretical perspectives on suicide in gay men with AIDS.

Suicide among gay men with AIDS constitutes a significant theoretical and practical problem. In order to understand this problem it is necessary to consider the specific circumstances that surround these individuals. Whilst there are many theories of suicide with which to address the problem, few are able to capture the special context within which gay men with AIDS live. This article explores three broad concepts from the theoretical literature on suicide that have explanatory potential in this unique context. The three concepts are: the search for meaning in the midst of suffering, Shneidman's [Shneidman, E., 1985. Definition of Suicide. John Wiley, New York] notion of unendurable psychological pain, and hopelessness. This article attempts to demonstrate how these three concepts can incorporate the experiences of gay men with AIDS and contribute to understanding the problem of suicide in this population.

Severity and stability of glaucoma: patient perception compared with objective measurement.

OBJECTIVE: To elucidate the relationship between the subjective assessment in patients with glaucoma of (1) the severity of their visual loss, and (2) any deterioration in their visual function and their objective visual fields as measured by computed perimetry. DESIGN: First, patients completed a questionnaire relating to perceived visual disability and underwent binocular visual field testing. Second, a separate group of patients answered a question about perceived visual deterioration: their monocular visual field tests were analyzed retrospectively by pointwise linear regression to establish stability or deterioration. SETTING: The Glaucoma Service of a specialist eye hospital, which is a tertiary referral center and serves the local community. SUBJECTS: One hundred twenty-three patients with glaucoma including 62 for the severity arm of the study and 61 for the progression arm. MAIN OUTCOME MEASURES: Questionnaire responses, Esterman binocular disability score, and objective visual field deterioration. RESULTS: Questions strongly associated with Esterman binocular disability scores related to bumping into things, problems with stairs, and finding things that have been dropped. There was a strong association between perceived visual deterioration and measured bilateral visual field deterioration (P<.01). CONCLUSIONS: There is a strong association between some types of perceived visual disability and the severity of binocular field loss. A patient who notices gradual visual deterioration is twice as likely to have bilateral visual field deterioration as not. The findings in this sample of patients with mild-to-moderate glaucoma challenge the belief that glaucoma is an insidious process in which the symptoms do not appear until the end stage of the disease.

Simulating binocular visual field status in glaucoma.

AIMS: To simulate the central binocular visual field using results from merged left and right monocular Humphrey fields. To assess the agreement between the simulation and the binocular Humphrey Esterman visual field test (EVFT). METHOD: 59 consecutive patients with bilateral glaucoma each recorded Humphrey 24-2 fields for both eyes and binocular EVFT on the same visit. EVFT results were used to identify patients exhibiting at least one defect (< 10 dB) within the central 20 degrees of the binocular field. This criterion is relevant to a patient's legal fitness to drive in the UK. Individual sensitivity values from monocular fields are merged to generate a simulated central binocular field. Results are displayed as a grey scale and as symbols representing defects at the < 10 dB level. Agreement between patients failing the criterion using the simulation and the EVFT was evaluated. RESULTS: Substantial agreement was observed between the methods in classifying patients with at least one defect (< 10 dB) within the central binocular field (kappa 0.81; SE 0.09). Patients failing this criterion using the EVFT results were identified by the binocular simulation with high levels of sensitivity (100%) and specificity (86%). CONCLUSIONS: Excellent agreement exists between the simulated binocular results and EVFT in classifying glaucomatous patients with central binocular defects. A rapid estimate of a patient's central binocular field and visual functional capacity can be ascertained without extra perimetric examination.

High spatial resolution automated perimetry in glaucoma.

BACKGROUND: Automated perimetry is of fundamental importance in assessing visual function in glaucoma. A technique was evaluated to perform high spatial resolution automated perimetry to allow a more detailed assessment of the luminance sensitivity in selected regions of the visual field than is possible with conventional perimetry. METHOD: High spatial resolution perimetry was performed using a Humphrey automated perimeter by measuring luminance sensitivity across a 9 by 9 degree custom grid of 100 test locations with a separation between adjacent locations of 1 degree. Quantitative analysis of the raw and Gaussian filtered thresholds was performed to assess the repeatability of the technique in normals, glaucoma suspects, and glaucoma patients. RESULTS: The testing protocol was well tolerated by all subjects. High spatial resolution perimetry in glaucomatous eyes demonstrated fine luminance sensitivity loss not suspected with conventional perimetry. High spatial resolution perimetry also demonstrated reproducible areas of sensitivity loss in some glaucomatous eyes in areas of the visual field which appear normal with conventional programmes. The repeatability of the technique correlated with mean threshold sensitivity and was substantially improved to clinically acceptable levels by Gaussian filtering the thresholds. CONCLUSION: This technique of high spatial resolution perimetry allows the practical assessment of selected regions of the visual field at higher resolution than conventional perimetry, and may be clinically useful in glaucoma.