Compliance: clear communication's critical.
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Antihypertensive Agents↗
Biomedical subjects
A F Spencer
Publications and source records attributed to A F Spencer.
The effectiveness of the Heidelberg Retina Tomograph and laser diagnostic glaucoma scanning system (GDx) in detecting and monitoring glaucoma.
OBJECTIVES: To determine the potential of optic nerve head tomography [Heidelberg Retina Tomograph (HRT)] and scanning laser polarimetry (GDx) for identifying patients with glaucomatous visual field loss. DESIGN: Examinations were performed with the HRT, GDx and Humphrey Field Analyzer (HFA). Glaucoma was defined by the presence of a field defect. Patients within the cross-sectional groups underwent a single examination, whereas patients in the longitudinal groups were examined 6 monthly, for an average of 3.5 years. SETTING: Manchester Royal Eye Hospital, UK. PARTICIPANTS: Patients with primary open angle glaucoma (POAG) or who were at risk of developing glaucoma. INTERVENTIONS: The diagnostic accuracies of the HRT and GDx were compared; specificity was set at 95%. The rate of change was determined by linear regression. To estimate the clinical application of the instruments, the proportion of an unselected group of patients on whom the examinations could be performed was calculated. Additionally, the time taken to perform and process each examination was measured. MAIN OUTCOME MEASURES: The ability of the techniques to identify cases showing deterioration. The level of agreement and applicability of the techniques. Time taken to perform and process each examination. RESULTS: From the cross-sectional group, the maximum sensitivities of the HRT and GDx were 59% and 45%, respectively (at 95% specificity). From the two longitudinal cohorts, the level of agreement between the three instruments for identification of the development and deterioration of POAG was low. The applicability of the techniques was 80% (HRT), 88% (GDx) and 98% (HFA). The length of time to perform a full examination with each instrument was 12.3, 11.8 and 28.3 minutes, respectively. Agreement of HRT and GDx parameters between and within observers was largely good. CONCLUSIONS: There is poor agreement for detection of glaucoma between the HFA, HRT and GDx. The techniques are amenable to use in the clinical environment, but no single examination has sufficient diagnostic precision to be used in isolation; also, the imaging techniques were not universally applicable. Neither the HRT nor GDx should be viewed as a replacement for visual field examination. Further research is needed into why most patients within the longitudinal arms of the study showed very little deterioration and into determining aspects of the structure versus function relationship in glaucoma that may explain why any one technique fails to detect a proportion of cases.
Adult↗
Community refinement of glaucoma referrals.
AIM: To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS. METHODS: Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patient's GP was informed in all cases. RESULTS: The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately 17 pounds sterling per patient. CONCLUSION: Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.
Community Health Services↗
Unilateral nasal hemianopsia secondary to posterior subcapsular cataract.
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Cataract↗
Long term results of diode laser cycloablation in complex glaucoma using the Zeiss Visulas II system.
AIM: To investigate the safety and efficacy of the Zeiss Visulas II diode laser system in the reduction of intraocular pressure (IOP) in patients with complex glaucoma. METHODS: The authors analysed the medical records of patients who underwent trans-scleral diode laser cycloablation (TDC) at the Manchester Royal Eye Hospital during a 34 month period. 55 eyes of 53 patients with complex glaucoma were followed up for a period of 12-52 months (mean 23.1 months) after initial treatment with the Zeiss Visulas II diode laser system. RESULTS: Mean pretreatment IOP was 35.8 mm Hg (range 22-64 mm Hg). At the last examination, mean IOP was 17.3 mm Hg (range 0-40 mm Hg). After treatment, 45 eyes (82%) had an IOP between 5 and 22 mm Hg; in 46 eyes (84%) the preoperative IOP had been reduced by 30% or more. The mean number of treatment sessions was 1.7 (range 1-6). At the last follow up appointment, the mean number of glaucoma medications was reduced from 2.1 to 1.6 (p<0.05). In 10 eyes (18%), post-treatment visual acuity (VA) was worse than pretreatment VA by 2 or more lines. CONCLUSIONS: Treatment with the Zeiss Visulas II diode laser system can be safely repeated in order to achieve the target IOP. Treatment outcomes in this study were similar to those from previously published work using the Iris Medical Oculight SLx laser.
Adolescent↗
An evaluation of the administration of sub-Tenon local anaesthesia by a nurse practitioner.
AIM: To evaluate the administration of sub-Tenon local anaesthesia (LA) by a nurse practitioner. METHODS: 106 consecutive patients listed for cataract surgery were given sub-Tenon's anaesthesia by a nurse practitioner. The surgical procedure was performed within 15 minutes of the administration of the LA. Pain, state and adequacy of anaesthesia, appearance of the eye, and patient anxiety were measured. Patients' experiences of this new nursing role were gained through interview. RESULTS: At the beginning of surgery, few patients showed eye movement in any of the four quadrants and the surgeons reported that akinesia was inadequate in only seven (7.1%) cases. Three patients (3.3%) gave a pain score of 3 out of 10 or above during surgery whereas the surgeons assessed the pain relief to be inadequate in eight (8.1%) cases. Five (5.3%) patients required a top up of anaesthesia and 51 (39.8%) patients developed conjunctival chemosis in two or more quadrants. Overall, patients' comments indicate that they were pleased with the new service. CONCLUSION: The results suggest that nurse practitioner delivered sub-Tenon LA is an effective and safe method of LA administration for cataract surgery.
Adult↗
Agreement between ophthalmologists and optometrists in optic disc assessment: training implications for glaucoma co-management.
BACKGROUND: Many studies have estimated observer variability for optic disc assessment among experts, but there are few data on agreement between optometrists and ophthalmologists. The aim of this study is to report inter- and intraobserver agreement among optometrists and ophthalmologists in optic disc assessment and discuss the implications for glaucoma co-management. METHODS: Twelve observers (six optometrists and six ophthalmologists) graded 48 stereo-pairs of optic disc photographs from 48 patients on two separate occasions. Observers graded the vertical C/D ratio, the narrowest rim width and the presence/absence of disc haemorrhage. Agreement was assessed by calculating the standard deviation (SD) of differences and the kappa statistic, within and between observers. Systematic differences in grading between and within individuals were described by calculating mean differences. RESULTS: Intra-observer agreement is "substantial" and significantly better than inter-observer agreement for all disc features (P<0.0001). Intra-observer agreement is comparable for optometrists and ophthalmologists with regard to C/D ratio estimates. Although some optometrists show close agreement with ophthalmologists, overall agreement between optometrists and ophthalmologists is significantly worse than agreement among ophthalmologists alone for vertical C/D ratio (P=0.002) and disc haemorrhage (P=0.02). There are fewer inter-observer mean differences that differ significantly from zero among ophthalmologists (7%) than among optometrists (67%; chi2=11.63, P<0.001) or between optometrists and ophthalmologists (69%; chi2=16.7, P<0.001). There is evidence of systematic under-reading of C/D ratios by less experienced optometrists. CONCLUSION: Although individual optometrists can show good agreement with ophthalmologists on disc grading, the variation in individual performance indicates that training and accreditation in disc assessment is an essential prerequisite for participation by optometrists in glaucoma co-management.
Clinical Competence↗
Misalignment of flexible iris hook retractors for small pupil cataract surgery: effects on pupil circumference.
A graphical method was used to assess the effect on pupil shape and circumference of various flexible iris hook malpositions. Results confirmed that all hook malpositions necessitate increased pupil stretching to create space to perform a capsulorhexis of a given diameter. This method also confirmed that the addition of a fifth hook to create a pentagonal pupil reduces pupil stretching by 17%. A simple method of marking the limbus before hook insertion to ensure equidistant hook separation and thus minimize pupil stretching is suggested.
Cataract Extraction↗
Reproducibility of volumetric macular measurements in diabetic patients with the Heidelberg Retina Tomograph.
AIMS: To quantify diabetic macular edema by confocal scanning laser ophthalmoscopy and assess its usefulness by determining the reproducibility of topographic measurements at the macula. METHODS: The volumes above reference plane bound by a 2 mm diameter circle centred on the fovea were measured by two observers. The reference plane was adjusted to the lowest point of the height variation of the contour line. The reproducibility of this technique was assessed in 20 eyes of 20 diabetic patients of which 8 eyes had macular edema. Three HRT scans of each eye were obtained. The measurements of volume above reference plane of each scan were repeated three times. RESULTS: For all diabetic eyes, the intra scan coefficients of variability measured 14.71% to 21.21%, the inter scan coefficient of variability was 30.46%. The average standard deviations were 0.053 mm3 for one examination per scan, 0.047 mm3 for two examinations per scan and 0.044 mm3 for three examinations per scan. Linear regression demonstrated an increase in standard deviation with greater volumetric measurements (p < 0.001). We found good correlation (r = 0.959, p < 0.001) and strong agreement between the two observer's findings for all 20 eyes. For the 8 eyes with macular edema, the coefficients of variability were similar to those calculated for all 20 eyes. The average SD for one examination per scan were 0.078 mm3, 0.069 mm3 for two examinations per scan and 0.062 mm3 for three examinations per scan. We found good correlation (r = 0.945, p < 0.001) and strong agreement between the two observer's findings in eyes with edema. CONCLUSION: The reproducibility of this technique has been demonstrated in diabetic eyes. This may have useful clinical applications for the quantification of diabetic macular edema and monitoring of laser therapy.
Adult↗
"Cyclodiode": results of a standard protocol.
AIMS: To analyse the results of intraocular pressure (IOP) reduction in refractory glaucoma following diode laser cyclophotocoagulation with a repeatable standard protocol. METHODS: 58 eyes of 53 patients were followed for 6-37 months (mean 19 months) after initial cyclodiode treatment. RESULTS: Mean (SD) pretreatment IOP for the 58 eyes was 33.0 mm Hg (10.7) reducing at final index visit to 16.7 mm Hg (7.8) (p < 0.0001). The mean antiglaucoma medication score per eye was significantly reduced from 2.4 (0.8) to 1.4 (1.0) at last index visit (p < 0.0001) with 91% of patients able to stop oral acetazolamide. 45% of eyes required more than one treatment and the overall mean per eye was 1.6 (range 1-5). Of eyes with visual acuity 6/60 or better pretreatment, 12 (32%) lost more than two lines of Snellen acuity and two eyes with poorer acuity initially dropped to NPL. Poor visual outcome was associated with the presence of diabetic retinopathy. Hypotony (IOP < 5 mm Hg) was noted in two eyes at the last index visit although neither had specific signs of the same. No phthisis was seen. CONCLUSION: The simple treatment protocol, repeated if necessary, appears relatively safe and effective at lowering IOP in eyes with refractory glaucoma.
Adolescent↗
An unusual side effect of Dorzolamide.
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Antihypertensive Agents↗
Repeatability and reproducibility of optic disc measurement with the Zeiss 4-mirror contact lens.
BACKGROUND: A simple clinical quantitative method of optic disc diameter measurement using a 4-mirror gonioscope contact lens has been described recently. METHODS: Intraobserver and interobserver variations are assessed on 77 eyes of 41 patients. Of these eyes, 63 had refractive errors within 3 diopters of emmetropia. The disc was measured by projecting a slit beam of known height onto the disc. RESULTS: Intraobserver variation: the coefficient of variation was 3.04% for observer 1 (experienced) and 4.76% for observer 2 (novice). The mean of the three measurements by the two observers was not significantly different (P=0.2318). For observer 1, the mean variance of the eyes with higher refractive errors did not differ significantly from the eyes with lower refractive errors. Interobserver variation: the coefficient of variation was 4.52%. The measurements for the novice were slightly larger the smallest discs and slightly smaller for the largest discs (regression analysis P=0.0209). CONCLUSION: Repeatability and reproducibility for this method are comparable with other methods of measurement. Until experienced with the technique, the authors recommend that the mean of three readings is used.
Glaucoma↗
Optic disc height measurement with the Zeiss 4-mirror contact lens and 78 dioptre lens compared.
Measurements of optic disc diameter with the Zeiss 4-mirror contact lens and 78 dioptre (D) lens, made by projecting a slit-beam of known height onto the image of the disc, were compared with planimetric measurements in 30 eyes. The 78 D lens measurements were significantly larger than both the Zeiss lens and planimetric measurements (p < 0.0001 and p = 0.0047 respectively). The measurements using the Zeiss lens and planimetry did not differ significantly. Compared with planimetry, for the 24 eyes within 3 D of emmetropia, the correlation was greater for the Zeiss (r = 0.8591) than for the 78 D lens (r = 0.7148). The Zeiss lens also showed better agreement and less scatter of results compared with the 78 D lens (standard error of the mean +/- 0.0373 mm for the Zeiss and +/- 0.0418 mm for the 78 D lens). The Zeiss contact lens measurements of optic disc diameter show stronger correlation and better agreement with planimetry than measurements using a 78 D lens.
Contact Lenses↗
Comparison of a simple ophthalmoscopic and planimetric measurement of glaucomatous neuroretinal rim areas.
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Glaucoma↗
Intraocular pressure control following microtrabeculectomy.
The use of the Kelly Descemet's membrane punch enables the glaucoma surgeon to perform smaller trabeculectomies. The outcome of 'microtrabeculectomy' employing a 2 x 2 mm superficial scleral flap and a 0.75 mm internal osteum was evaluated on 65 eyes of 50 patients (mean age 70 years). The operation site was nasal in left eyes and temporal in right eyes. In the 56 eyes where 5-fluorouracil was not used, the mean intraocular pressure (IOP) on diagnosis was 33.4 mmHg, the mean pre-operative IOP being 25.1 mmHg. After a mean follow-up of 13.4 months (minimum 3 months) following surgery, the mean IOP was 13.4 mmHg with 88% of eyes controlled at < 21 mmHg on no medications. Nasally sited microtrabeculectomies resulted in lower IOPs than temporally sited procedures (11.8 vs 14.9 mmHg, p = 0.003) at last follow-up visit.
Adult↗
Optic disc measurement: a comparison of indirect ophthalmoscopic methods.
AIMS: Two methods of indirect ophthalmoscopic estimation of optic disc size, the 78 dioptre lens and optic disc biometer were evaluated. METHODS: Twenty nine eyes of 29 patients were measured by both methods and compared with optic disc size calculated using the three planimetric corrections described by Bengtsson and Krakau. RESULTS: The closest agreement with the clinical measurements was found using correction 3. There was a significant difference between both the 78 D lens (p < 0.0001) and the biometer (p = 0.0027) and the planimetric results. There was also a significant difference between the two clinical methods (p < 0.0001). Both methods showed acceptable intraobserver variation (CoV 2.45% and 3.13% respectively). CONCLUSION: Overall, both methods give larger measurements than planimetry; the 78 D lens by 0.41 mm and the biometer by 0.15 mm. Neither method gives a satisfactory estimation of optic disc size when compared with planimetry.
Biometry↗
Vertical optic disk diameter: discrepancy between planimetric and SLO measurements.
PURPOSE: To compare measurements of the vertical diameter of the optic disk using the Heidelberg Retinal Tomograph (HRT) and planimetric methods. METHODS: On the HRT, three measurements of the vertical disk diameter were made on 32 eyes from a composite image using the circle draw facility and were compared with three measurements of the central image of the 32 tomographic cuts. These were repeated by a second observer. Measurements were compared with those obtained from photographs using the three corrections described by Bengtsson and Krakau. RESULTS: For the HRT, there was minimal intraobserver variation, coefficient of variation (1.515% to 1.882% for the two observers). Interobserver variation was also small (CoV 1.969%). The authors found the closest agreement with the HRT measurements using regression analysis was obtained using correction 3 (r = 0.8258). HRT measurements were significantly smaller (P < 0.0001) by a constant amount of 0.13 mm across the range of optic disk size. There was a significant difference between the HRT measurement of the composite image and the central cut (P = 0.0003 for observer 1). CONCLUSIONS: HRT measurements are significantly smaller than those from photographs and, therefore, are not interchangeable.
Glaucoma↗
Optic disc measurement with the Zeiss four mirror contact lens.
A knowledge of the optic disc size may be of value when assessing the glaucoma suspect. The vertical diameter of the optic disc was measured using a Zeiss four mirror gonioscope and a 900 Haag-Streit slit-lamp in one eye of 39 patients, 32 with refractive errors within 3 dioptres of emmetropia. The disc was measured by projecting a slit beam of known height onto the image of the disc. A magnification factor for the contact lens was calculated from first principles and disc height recalculated. These measurements were compared with those obtained by photographic methods using the corrections suggested by Bengtsson and Krakau. In the analysis on the 32 eyes within 3 dioptres of emmetropia the best correlation with clinical measurements was obtained with correction 3 using spectacle refraction and keratometry (r = 0.8614). The contact lens measurement was within plus or minus 0.1 mm of the photographic measurement in 67% of cases and plus or minus 0.2 mm in all cases. This simple method is advocated for the routine assessment of optic disc size.
Contact Lenses↗