Direct healthcare costs of glaucoma treatment.

AIMS: To report the complete lifetime direct healthcare costs of glaucoma treatment in a database of 1136 patients attending the Glaucoma Clinic at Glasgow Royal Infirmary, Glasgow, UK. METHOD: The database was interrogated to identify all patients who had initiated treatment at the Glaucoma Clinic at Glasgow Royal Infirmary, and who had subsequently died of natural causes. The healthcare resource use based cost assessment was based on two aspects of the direct National Health Service cost: drug costs (prescribed medications) and non-drug costs (inpatient or outpatient/and surgical or procedure costs). RESULTS: 106 patients (53 men, 53 women) were identified for whom there were lifetime treatment data. The mean lifespan of the patients was 80.5 years, and the mean number of years attending the glaucoma clinic was 7.05 years (range 1-22 years). The mean cost of glaucoma treatment over the lifetime of the patients was £3001, with an annual mean cost per patient of £475. Non-drug and drug costs made up 66% and 34% respectively, of the lifetime costs. CONCLUSIONS: This is the only study to directly assess the lifetime treatment costs of glaucoma. Awareness of the costs of glaucoma treatment may be of increased importance in these financially challenging times.

Persistence of glaucoma medical therapy in the Glasgow Glaucoma Database.

AIMS: To report the persistence of glaucoma medical therapy in a database of 1006 patients with ocular hypertension (OHT), normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) attending the Glaucoma Clinic at Glasgow Royal Infirmary, Glasgow, UK. METHOD: Analyses have been carried out using specially written queries to generate reports relating to initial treatment choice and persistence for individual drugs. Queries were investigated in the database time period from 16 February 1982 to 11 February 2009. When investigating drug persistence, the results from the database were split into two distinct time periods from 1997 to 2001 and from 2002 to 2009 to reflect the available treatment options used. RESULTS: The number of patients with each diagnosis was as follows: POAG 608; OHT 246; NTG 152. The Kaplan-Meier estimate for mean persistence from 1997 to 2001 (time to treatment discontinuation) of latanoprost was 58.8 ± 1.95 months, timolol was 41.8 ± 3.94 months, brimonidine was 24.1 ± 3.05 months, and betaxolol was 22.9 ± 2.04 months. The Kaplan-Meier estimate for mean persistence from 2002 to 2009 of latanoprost (time to treatment discontinuation) was 52.0 ± 2.26 months, bimatoprost was 25.8 ± 2.89 months, and travoprost was 23.0 ± 1.27 months. The Kaplan-Meier estimate for mean persistence of latanoprost (time to treatment change) was 37.5 ± 2.47 months, travoprost was 30.2 ± 2.70 months, and bimatoprost was 17.5 ± 2.88 months. CONCLUSION: The introduction of the first prostaglandin analogue, latanoprost, dramatically improved treatment persistence for glaucoma patients. In the current prostaglandin-rich treatment environment, these data do not show any significant differences between prostaglandins with respect to treatment persistence.

Surveillance of glaucoma medical therapy in a Glasgow teaching hospital: 26 years' experience.

AIMS: To report the initial findings of a unique database of 956 patients with ocular hypertension (OHT), normal tension glaucoma (NTG) and primary open angle glaucoma (POAG) attending the Glaucoma Clinic at Glasgow Royal Infirmary, Glasgow, UK. METHOD: The database contains retrospective data from 1981 and prospective data from 1999. Analyses have been carried out using specially written queries to generate reports relating to prescription trends and reasons for treatment discontinuation. RESULTS: The database included the following numbers of patients: POAG 580; OHT 242; NTG 134. Of 2928 treatment-change episodes recorded, failure to reach or maintain a target intraocular pressure (IOP) accounted for 51.9%, while adverse effects accounted for 22.1%. Use of latanoprost has increased sharply since 1996, and that of brimonidine, betaxolol and dorzolamide has declined significantly. Bimatoprost had a higher rate of discontinuation due to adverse effects (25%) than travoprost (16.3%) or latanoprost (12.4%), but this was only statistically significant between latanoprost and bimatoprost (p = 0.0038). In 2000 the database informed the introduction of a new treatment protocol that resulted in a fall in discontinuations due to adverse effects by almost two-thirds. CONCLUSION: A large and unique treatment database has been established at the Glaucoma Clinic of Glasgow Royal Infirmary. Containing data spanning a 26-year period, it promises to be an invaluable resource for audit and research. It has already demonstrated its worth by informing changes in prescribing practice that have resulted in direct patient benefit.

The use of a "cheese-wire" suture in trabeculectomy.

AIM: To report a preliminary study on the safety and efficacy of the use of a cheese-wire suture in trabeculectomy. PATIENTS AND METHODS: The case notes of 32 eyes of 25 patients with medically uncontrolled glaucoma who underwent trabeculectomy with cheese-wire suture at Stobhill Hospital, Glasgow, UK, between July 2001 and September 2002 were studied retrospectively. Diagnoses included primary open angle glaucoma (n = 24), normal tension glaucoma (n = 3), angle closure glaucoma (n = 2), ocular hypertension (n = 1), angle recession glaucoma (n = 1) and combined mechanism glaucoma (n = 1). The mean presenting intraocular pressure (IOP) was 29.5 mm Hg and mean intraocular pressure before operation was 23.5 mm Hg OUTCOME MEASURES: Success was defined as lowering of IOP by at least 15% compared with IOP before removal. RESULTS: A total of 20 eyes (62%) underwent removal of the cheese-wire suture. 17 eyes (85%) underwent removal for therapeutic reasons (failing/failed blebs) and three eyes (15%) underwent suture removal as the suture loops were exposed. The timing of removal was between 2 weeks and 12 months following surgery. A successful outcome was seen in 12/17 (70%) eyes in the eyes that had therapeutic suture removal. 15 eyes had undergone previous surgical interventions (trabeculectomy n = 12, extracapsular cataract extraction n = 1 and laser peripheral iridotomies n = 2). Mean IOP before removal was 23.66 mm Hg and mean IOP immediately following removal was 11.33 mm Hg. Of the 32 eyes that underwent trabeculectomy with cheese-wire suture, 24 eyes had intraoperative mitomycin C and one eye had 5-fluorouracil. The remaining seven eyes did not have any antimetabolites. Early complications related to the surgical procedure included conjunctival haematoma in one eye (3%), corneal abrasion in one eye (3%), wound leak in five eyes (15%), shallow anterior chamber in one eye (3%), hyphaema in six eyes (18%), choroidal effusion in six eyes (18%) and raised IOP in two eyes (6%). Late complications of suture exposure occurred in three eyes (9%). Complications related to removal of the cheese-wire suture included suture breakage in two eyes (10%), hypotony in one eye (5%) and transient hyphaema in one eye (5%). CONCLUSION: The use of cheese-wire suture in trabeculectomy appears to be safe and may provide an alternative strategy in the management of bleb failure.

Alphagan allergy may increase the propensity for multiple eye-drop allergy.

AIMS: Since its introduction in 1996, brimonidine tartrate 0.2% ophthalmic solution (Alphagan, Allergan) twice daily has become established as an effective intra ocular pressure-lowering treatment. While the efficacy of Alphagan cannot be questioned, we gained the clinical impression that the drug has an unacceptably high rate of allergy. Of greater concern, we suspected that patients suffering from local Alphagan allergy had a higher rate of allergy to subsequently used topical preparations. We analysed data from a large scale study of glaucoma patients to establish whether our suspicions were correct. SUBJECTS AND METHODS: We have created a database of the entire glaucoma treatment histories for consecutive patients attending a single consultant's clinics (DMIM) at Glasgow Royal Infirmary between May 1999 and September 2001. All have undergone medical treatment for primary open angle glaucoma, ocular hypertension, or normal tension glaucoma. Patients with any other form of glaucoma, and patients in whom a full record of treatment was not available were excluded from the study. RESULTS: Alphagan was discontinued due to allergy on 73 per 100,000 patient treatment days. This was a far higher frequency than for other preparations. In patients allergic to both Alphagan and another preparation (Timoptol, Trusopt and Xalatan), the mean interval between the first and second allergy was shorter when Alphagan allergy occurred first. This was statistically significant in Timoptol and Trusopt cross-reactivity. CONCLUSIONS: Alphagan has high allergenicity, and may increase the likelihood of allergy to subsequently used preparations.

Associations between passive immunity and morbidity and mortality in dairy heifers in Florida, USA.

A prospective cohort study was undertaken to determine calf-level factors that affected calf health status between birth and 6 months of age. A convenience sample of approximately 3300 female Holstein calves born in 1991 on two large Florida dairy farms was used for the study. Data collected on each calf at birth included farm of origin, weight, height at the pelvis, birth date, and serum total protein (a measure of colostral immunoglobulin absorption). Birth season was dichotomized into summer and winter using meteorological data collected by University of Florida Agricultural Research Stations. Health data including date of initial treatment and number of treatments were collected for the diseases diarrhea, omphalitis, septicemia and pneumonia. All calves were followed for 6 months. Cumulative incidences of mortality and occurrence of diarrhea, omphalitis, septicemia and pneumonia were 0.12, 0.35, 0.11, 0.24 and 0.21, respectively. Serum total protein (TP) was a significant risk factor for mortality. The association of TP and mortality was quadratic and showed a dramatic decrease in mortality as TP increased from 4.0 to 5.0 g/dl, a small improvement from 5.0 to 6.0 g/dl and virtually no improvement in mortality rates as TP increased over 6.0 g/dl. The hazard mortality ratio was constant from birth to six months, indicating that the increased risk of mortality associated with low levels of TP was evident through six months of age. No interactions between TP, farm, season, or birth weight were found in these analyses. Serum total protein concentration was a significant risk factor for the occurrences, age of onset and severity of septicemia and pneumonia. The association between TP and septicemia was linear and an interaction with birth season was found. The association between TP and pneumonia was quadratic, and in contrast to the TP-and-septicemia relationship, the morbidity hazard ratio for pneumonia was not constant over the time measured; that is, colostral immunity protected the calf from developing pneumonia early in life, but this effect disappeared as the calf got older. Total protein was not a significant risk factor for diarrhea or omphalitis.

Calf and disease factors affecting growth in female Holstein calves in Florida, USA.

A prospective cohort study was undertaken to determine calf-level factors that affect performance (growth) between birth and 14 months of age in a convenience sample of approximately 3300 female Holstein calves born in 1991 on two large Florida dairy farms. Data collected on each calf at birth included farm of origin, birth date, weight, height at the pelvis, and serum total protein (a measure of colostral immunoglobulin absorption). Birth season was dichotomized into summer and winter using meteorological data collected by University of Florida Agricultural Research Stations. Data collected at approximately 6 and 14 months of age included age, weight, height at the pelvis, and height at the withers. Growth in weight and stature (height) was calculated for each growth period; growth period 1 (GP1) = birth to 6 months, and growth period 2 (GP2) = 6 to 14 months. Health data collected included data of initial treatment and number of treatments for the diseases diarrhea, omphalitis, septicemia, pneumonia and keratoconjunctivitis. After adjusting for disease occurrence, passive transfer of colostral immunoglobulins had no significant effect on body weight gain or pelvic height growth. Season of birth and occurrence of diarrhea, septicemia and respiratory disease were significant variables decreasing heifer growth (height and weight) in GP1. These variables plus farm, birth weight and exact age when '6 month' data were collected explained 20% and 31% of the variation in body weight gain and pelvic height growth, respectively, in GP1. The number of days treated for pneumonia before 6 months of age significantly decreased average daily weight gain in GP2 (P < 0.025), but did not affect stature growth. Treatment for pneumonia after 6 months of age did not significantly affect weight or height gain after age 6 months. Neither omphalitis nor keratoconjunctivitis explained variability in growth in either of the growth periods.

1997 Volvo Award winner in clinical studies. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation.

STUDY DESIGN: This prospective study analyzed the influence of transpedicular instrumented on the operative treatment of patients with degenerative spondylolisthesis and spinal stenosis. OBJECTIVES: To determine whether the addition of transpedicular instrumented improves the clinical outcome and fusion rate of patients undergoing posterolateral fusion after decompression for spinal stenosis with concomitant degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Decompression is often necessary in the treatment of symptomatic patients who have degenerative spondylolisthesis and spinal stenosis. Results of recent studies demonstrated that outcomes are significantly improved if posterolateral arthrodesis is performed at the listhesed level. A meta-analysis of the literature concluded that adjunctive spinal instrumentation for this procedure can enhance the fusion rate, although the effect on clinical outcome remains uncertain. METHODS: Seventy-six patients who had symptomatic spinal stenosis associated with degenerative lumbar spondylolisthesis were prospectively studied. All patients underwent posterior decompression with concomitant posterolateral intertransverse process arthrodesis. The patients were randomized to a segmental transpedicular instrumented or noninstrumented group. RESULTS: Sixty-seven patients were available for a 2-year follow-up. Clinical outcome was excellent or good in 76% of the patients in whom instrumentation was placed and in 85% of those in whom no instrumentation was placed (P = 0.45). Successful arthrodesis occurred in 82% of the instrumented cases versus 45% of the noninstrumented cases (P = 0.0015). Overall, successful fusion did not influence patient outcome (P = 0.435). CONCLUSIONS: In patients undergoing single-level posterolateral fusion for degenerative spondylolisthesis with spinal stenosis, the use of pedicle screws may lead to a higher fusion rate, but clinical outcome shows no improvement in pain in the back and lower limbs.

Efficacy of closed wound suction drainage after single-level lumbar laminectomy.

The use of closed suction drainage after spinal surgery remains controversial. The purpose of this study was to determine the indications for closed suction drainage after single-level lumbar surgery. Two hundred patients who were scheduled to undergo single-level lumbar surgery without fusion were prospectively randomized into two groups. One group had a closed wound suction drain placed deep to the lumbodorsal fascia before routine closure, whereas the second group had no drain placed. Hemostasis was achieved in all patients before the surgeon had knowledge of the randomization outcome. All drains were removed on the 2nd postoperative day, and the amount of drainage was recorded. After surgery, the patients were evaluated for signs and symptoms of continued wound drainage, hematoma/seroma formation, and/or infection as well as evidence of an acquired neurologic deficit. One hundred three patients had a drain placed before closure and two patients developed postoperative wound infection, both of which were successfully treated with orally administered antibiotics. Of the 97 patients who had no drain placed after the surgical procedure, one patient developed a postoperative wound infection that was treated with surgical incision and drainage, as well as intravenously administered antibiotics. Statistical analysis revealed that the presence or absence of a drain did not affect the postoperative infection rate. No new neurologic deficits occurred in any postoperative patient. The use of drains in single-level lumbar laminectomy without fusion did not affect patient outcome. There was no significant difference in the rate of infection or wound healing and no patient developed a postoperative neurologic deficit.

Objective detection of hemifield and quadrantic field defects by visual evoked cortical potentials.

AIMS/BACKGROUND: An objective method for detecting hemifield and quadrantic visual field defects has been developed using steady state visual evoked cortical potentials (VECPs), an adaptive noise canceller (ANC), and Hotelling's t2 statistic. The purpose of this study was to determine the sensitivity and specificity of the technique. METHODS: Nine subjects (mean age 44 years) were investigated with field loss due to a variety of causes including both anterior and posterior visual pathway lesions. Dynamic perimetry was performed by means of a Goldmann or Tübingen perimeter. VECP recordings were made from each visual field quadrant (23 degrees X 23 degrees) by means of a steady state reversing checkerboard (7.7 rev/s). The central 5 degrees of the visual field and the vertical and horizontal meridians were masked during these measurements. Recordings were made from three electrode sites, positioned over the visual cortex, relative to a mid frontal electrode. Each recording lasted 2 minutes, during which time fixation was monitored. The data from each recording were divided into 4 second segments, and the amplitude and phase of the VECP signal measured using the ANC. Hotelling's t2 statistic was applied to determine the probability of signal detection. Receiver operating characteristic curves were used to find the optimum signal detection threshold for identification of the visual field defects. RESULTS: The results of the study confirmed patterns of subjective visual field loss. The technique had a sensitivity and a specificity of 81% and 85%, respectively, for detecting 'non-seeing' areas in the inferior visual field, and 82% and 89%, respectively, for detecting 'non-seeing' areas in the superior visual field. CONCLUSION: These results demonstrate that the technique is of potential clinical value to ophthalmologists and neurologists when subjective perimetry is not possible.

Determination of the neuroretinal rim area using the horizontal and vertical disc and cup diameters.

BACKGROUND: This study evaluated whether the neuroretinal rim area can be calculated on the basis of the horizontal and vertical diameters of the optic disc and cup applying the formula of an ellipse. METHODS: Color stereo optic disc photographs of 587 normal subjects and 1193 patients with glaucoma were morphometrically examined. In a first method, the areas of the optic disc and cup were planimetrically measured and the area of the neuroretinal rim was determined as optic disc area minus cup area. In a second method, the optic disc and cup were assumed to have an elliptical shape. Their areas were calculated by applying the formula of an ellipse, taking into account their horizontal and vertical diameters. As in the first method, the rim area was then determined as disc area minus cup area. RESULTS: The values of the neuroretinal rim area as measured using the first method differed by 0.05 +/- 0.05 mm2 from the values as calculated by the second method. The average error was 2.8 +/- 2.9% for the normal group and 8.2 +/- 20.8% for the glaucoma patients. It increased with decreasing neuroretinal rim area and increasing mean visual field defect. CONCLUSIONS: For clinical purposes, the neuroretinal rim area can be determined on the basis of the horizontal and vertical diameters of the optic disc and cup. The horizontal and vertical disc and cup diameters being determinable upon ophthalmoscopy, this finding is important for the direct measurement of optic disc morphology during any ophthalmoscopic examination.

Phosphatase production and activity in Citrobacter freundii and a naturally occurring, heavy-metal-accumulating Citrobacter sp.

The ability of a naturally occurring Citrobacter sp. to accumulate cadmium has been attributed to cellular precipitation of CdHPO4, utilizing HPO4(2-) liberated via the activity of an overproduced, Cd-resistant acid-type phosphatase. Phosphatase production and heavy metal accumulation by batch cultures of this strain (N14) and a phosphatase-deficient mutant were compared with two reference strains of Citrobacter freundii. Only strain N14 expressed a high level of acid phosphatase and accumulated lanthanum and uranyl ion enzymically. Acid phosphatase is regulated via carbon-starvation; although the C. freundii strains overexpressed phosphatase activity in carbon-limiting continuous culture, this was approximately 20-fold less than the activity of strain N14 grown similarly. Citrobacter strain N14 was originally isolated from a metal-contaminated soil environment; phosphatase overproduction and metal accumulation were postulated as a detoxification mechanism. However, application of Cd-stress, and enrichment for Cd-resistant C. freundii ('training'), reduced the phosphatase activity of this organism by about 50% as compared to Cd-unstressed cultures. The acid phosphatase of C. freundii and Citrobacter N14 had a similar pattern of resistance to some diagnostic reagents. The enzyme of the latter is similar to the PhoN acid phosphatase of Salmonella typhimurium described by other workers; the results are discussed with respect to the known phosphatases of the enterobacteria.

Palpable unilateral sacral prominence as a clinical sign of lower limb anisomelia: a pilot study.

OBJECTIVE: To examine the role of oblique-axis sacral torsion in the presence of true or apparent short leg. DESIGN: Prospective blind trial of eighteen subjects. SETTING: A suburban chiropractic practice, a hospital and a university campus. SUBJECTS: Of 33 subjects selected, 27 completed the study, 8 exhibited elimination criteria, and 1 X-ray was nondiagnostic. MAIN RESULTS: 3 x 3 contingency table showed the presence of unilateral sacral prominence as statistically significant (p > .001) in subjects with LLI. The incidence of unilateral sacral prominence on the short leg side was also significant (p > .05). Weighted kappa confirmed both (alpha > .001). CONCLUSIONS: Oblique-axis sacral torsion may play a role in intrapelvic adaptation to anisomelia of the lower limb; further examination of this prospect is warranted.

Quantitative assessment of the blue-light hazard during indirect ophthalmoscopy and the increase in the "safe" operating period achieved using a yellow lens.

PURPOSE: The indirect ophthalmoscope presents a blue-light hazard with the potential for causing photochemical injury to the retina. In this study, this hazard was assessed with respect to the threshold limit values (TLVs) recently adopted by the American Conference of Governmental Industrial Hygienists. METHOD: Spectral radiometric measurements were made from a standard indirect ophthalmoscope headset used in conjunction with either a clear or a yellow lens. The results were weighted spectrally with the published blue-light hazard function. RESULTS: When the clear lens was used, the TLV was exceeded after approximately 2.5 minutes. The yellow lens filtered out the more hazardous blue wavelengths of light and this increased the "safe" operating period by a factor of approximately 20. CONCLUSION: In clinical practice, with a clear lens, the TLV could be exceeded easily if the patient is subjected to prolonged or repeated examination because the blue-light hazard is additive in a linear manner for periods as long as 3 hours with a potential for a cumulative effect over longer periods. Furthermore, some ophthalmic patients, such as those with aphakia, are less tolerant of blue-light than healthy subjects. In the interests of patient safety, it is recommended that yellow lenses are considered for use for routine indirect ophthalmoscopy.

Passive reduction of spondylolisthesis on the operating room table: a prospective study.

Translational motion of low-grade spondylolisthesis is traditionally assessed with lateral flexion and extension radiographs. Maximum motion in an unanesthetized patient may be limited by patient cooperation, pain, or muscle spasm. Twenty-four patients with degenerative or isthmic spondylolisthesis were assessed with preoperative lateral flexion and extension radiographs. A lateral radiograph was obtained on the operating room table after administering an anesthetic, exposing the spine, and performing a laminectomy. The percentage slip decreased from 24 to 15 to 6% on flexion, extension, and intraoperative lateral radiographs, respectively (p < 0.001). The amount of reduction did not correlate with disc height, slip angle, slip level, or type of spondylolisthesis. Many low-grade spondylolisthesis deformities reduce almost completely on the operating table. Translational motion of spondylolisthesis is greater than preoperative flexion and extension radiographs indicate.

A personal computer-based visual evoked potential stimulus and recording system.

A system for recording electroretinograms and visual evoked cortical potentials has been constructed with the use of a personal computer and a digital signal processing card. The system is based on widely available commercial hardware. It has been designed to be capable of performing routine visual electrophysiology as well as allowing the development of novel visual stimuli and signal detection techniques. The system enables both transient and steady-state stimulation rates. Pattern stimuli can be presented in pattern-reversal, pattern-onset, pattern-offset or motion-onset modes. In addition to conventional signal averaging, the digital signal processing card can also provide on-line Fourier analysis and is facilitating the development of adaptive filtering techniques for the detection of steady-state visual evoked cortical potentials. This versatile system is in regular clinical use for the measurement of electroretinograms and visual evoked cortical potentials.

Optic disc interpretation in glaucoma: is confidence misplaced?

A photographic questionnaire has been used to investigate whether or not clinicians have realistic expectations of their ability to distinguish optic discs associated with glaucomatous visual field loss from discs of healthy eyes. The questionnaire consisting of 30 non-stereoscopic fundus photographs from 15 patients was administered to 40 ophthalmologists of varying experience and 10 optometrists. Each group displayed large discrepancies between their expected and achieved scores suggesting that clinicians may overestimate their ability to recognize the glaucomatous optic disc. This could lead to diagnostic errors especially in cases where tonometric and visual field parameters are considered equivocal. An over-reliance on the cup/disc ratio appeared to be the most likely cause of error.

Diagnosis and treatment of discogenic low back pain.

Low back pain (LBP) is very prevalent in the general population. Treatment of nonradicular back pain, in the absence of deformity, continues to be controversial. Recently, anatomic dissections, magnetic resonance imaging studies, and the use of provocative discograms (pain-related response during the injection similar to the typical pattern of pain reported prior to the procedure) have contributed to our understanding of the etiology of discogenic back pain. Various techniques of spine fusion, with and without instrumentation, have altered the natural history of LBP unresponsive to conservative treatment. This review discusses the etiology and diagnosis of discogenic back pain and the treatment options available to the spine surgeon.