Policy implications of regional variations in eye disease detection and treatment on Prince Edward Island: a repeated cross-sectional analysis, 2010-2012.

BACKGROUND: In Canada, government insurance covers eye care services provided by ophthalmologists and other physicians. However, government coverage for services provided by optometrists, non-medical school trained primary eye care providers, varies regionally. Little is known about the impact of a funding model in which ophthalmologist services are government-insured but services provided by optometrists are not, on eye care utilization and eye disease detection and treatment. We aimed to address this question by examining geographic variations in eye care service utilization on Prince Edward Island (PEI). METHODS: PEI physician-billing data from 2010 to 2012 was analyzed across five distinct geographic regions (Charlottetown, Summerside, Prince, Queens & Kings and Stratford). The residential location of patients and practice locations of eye care providers were identified using the first three digits of their respective postal code. Age-standardized rates were computed for comparisons across different regions. RESULTS: There were six ophthalmologists practicing on PEI, five with offices in Charlottetown. Twenty optometrists practiced on the island with offices across the province. Stratford is closest and Prince farthest from Charlottetown. Age-standardized utilization rates of ophthalmologists per 100 populations were 10.44 in Charlottetown and 10.90 in Stratford, which was significantly higher than in other regions (7.74-8.92; p < 0.05). The disparities were most pronounced amongst the elderly. The prevalence of glaucoma visits was higher in Charlottetown (6.10%) and Stratford (6.38%) and lower in other regions. A similar pattern was observed for the prevalence of cataract visits. While the prevalence of diabetes visits was higher in Prince and Summerside, the utilization of ophthalmologists by people with diabetes was almost twice as high in Charlottetown (6.49%) than in Prince (3.88%). CONCLUSIONS: The observed discrepancies in vision care utilization across geographic regions were likely attributed to barriers in accessing government-insured, geographically concentrated ophthalmologists, as opposed to a reflection of the true differences in eye disease occurrence. The lower prevalence of glaucoma visits in regions farther away from ophthalmologist offices may result in delayed detection and blindness in this population. Encouraging ophthalmologists to work in other areas of the province and/or to publicly fund services provided by optometrists may mitigate the observed disparities. TRIAL REGISTRATION: Not applicable.

Survey of equine castration techniques, preferences and outcomes among Australian veterinarians.

OBJECTIVES: (1) To collect the perceptions of veterinarians performing equine castrations in Australia on techniques, preferences and outcomes, (2) to investigate veterinarian use and experience with the Henderson castrating instrument and (3) to investigate potential associations between demographics, castration methods and techniques, and complications. DESIGN: Online survey of members of the Australian Veterinary Association's Special Interest Group, Equine Veterinarians Australia (EVA). METHODS: A link to the survey was included in the EVA e-newsletter and practices on the EVA website were contacted by telephone and follow-up email. Fisher's exact test was used to determine associations between ligation and complications. A generalised linear model with a negative binomial family was used to determine associations between count response variables and categorical independent variables. RESULTS: Responses were obtained from 138 veterinarians (response rate, 13.1%) who performed 5330 castrations over 12 months. Castrations were most commonly performed in the field, on anaesthetised horses, using emasculators, via an open approach and without ligation of the spermatic cord. Estimated complications after use of emasculators were swelling (25%), haemorrhage (5%) and infection (5%). The Henderson instrument was used by approximately 10% of respondents and its use for castration was associated with fewer reports of postoperative swelling compared with emasculators (P = 0.002). Rates of evisceration with the Henderson and emasculator methods were comparable (0.43% and 0.9%, respectively). CONCLUSION: Castration preferences varied widely among survey participants. Reported complication types and rates were comparable to those reported previously in other countries. Perceptions that the Henderson instrument was associated with less swelling should be investigated further via a prospective controlled investigation.

Pharmacokinetic and pharmacodynamic effects of two omeprazole formulations on stomach pH and gastric ulcer scores.

REASONS FOR PERFORMING THE STUDY: Limited data are available on the relative pharmacokinetics and pharmacodynamics of different omeprazole formulations. OBJECTIVES: To compare pharmacokinetic and pharmacodynamic effects of a novel omeprazole formulation against a currently registered product. STUDY DESIGN: Masked 2 period, 2 treatment crossover. METHODS: Twelve clinically healthy horses were studied over two 6-day treatment periods. Horses were randomly assigned to receive a novel omeprazole paste (Ulcershield: ULS) or a currently registered reference omeprazole product (OMO). Gastric pH was measured continuously for 10 h on the day prior to commencing treatment (Day -1) and after 6 days of oral treatment (Day 5) using in situ antimony pH probes within an indwelling nasogastric tube. Plasma pharmacokinetics were determined on Days 0 and 6. RESULTS: Treatment significantly (P<0.005) increased gastric pH on Day 5, compared to results obtained prior to treatment (Day -1) and there was no significant difference between products (P = 0.773). Similarly, comparison of median hourly gastric pH (P = 0.593), mean gastric pH (P = 0.154), percentage time pH<4 (P = 0.259) and area under the time-gastric pH response curve (P = 0.734) did not discriminate between products. Both treatments resulted in significantly lower gastric ulcer severity scores (both P = 0.004), with no difference between treatments (P = 0.688). Comparison of mean log area under time-plasma concentration curves demonstrated that, although the lower limit of the 90% confidence interval was within the -20% limit for bioequivalence, the upper limit was exceeded, suggesting that the test product could have greater bioavailability than the reference product. MAIN LIMITATIONS: The small sample size, large interhorse plasma omeprazole concentrations, and low bioavailability of omeprazole impacted the sensitivity of the bioequivalence analysis. CONCLUSIONS: ULS matched or slightly exceeded OMO plasma concentrations. Both products resulted in equivalent increases in gastric pH, gastric pH profiles and decrease in gastric ulcer scores. Thus, ULS was pharmacodynamically equivalent to OMO and was associated with an equivalent beneficial effect on gastric squamous mucosal ulceration.

Oesophageal lumen pH in yearling horses and effects of management and administration of omeprazole.

BACKGROUND: In human subjects, arytenoid chondritis can be caused by chemical trauma of mucosa attributable to gastro-oesophageal reflux. Although a similar process may be involved in the aetiopathogenesis of arytenoid chondritis in horses, the oesophageal lumen pH in this species is poorly understood. OBJECTIVES: To determine if gastro-oesophageal reflux occurs in horses by characterising oesophageal lumen pH. STUDY DESIGN: Blinded, randomised, placebo-controlled, crossover, experimental study. METHODS: Luminal oesophageal pH in six yearling horses was recorded over four 24 h periods using an ambulatory pH recorder attached to a catheter with two electrodes (proximal and distal) inserted into the oesophagus. Recordings of pH were made during three management protocols. Initially, horses grazed in a paddock (Protocol A). Horses were then moved to stables to simulate sale preparation of Thoroughbred yearlings, and were given either omeprazole (Protocol B) or placebo paste (Protocol C) orally once per day. Protocol A was repeated for each horse (after a 13 day washout period) between Protocols B and C. Summary statistics described pH range and frequency of pH changes. Associations with predictor variables were investigated using linear mixed-effects models. Data are presented as the mean ± s.d. RESULTS: Oesophageal lumen pH ranged from 4.90 to 9.70 (7.36 ± 0.27 and 7.18 ± 0.24 for the proximal and distal electrodes, respectively) and varied frequently (1.2 ± 0.9 changes/min and 0.8 ± 0.8 changes/min for the proximal and distal electrodes, respectively). Oesophageal lumen pH was associated with time since concentrate feeding, activity and time of day, but not with treatment of omeprazole. MAIN LIMITATIONS: A small number of horses were used and measurement periods were limited. CONCLUSIONS: Gastro-oesophageal reflux occurs in clinically normal yearling horses. Although omeprazole had no detectable effect, oesophageal lumen pH recorded during this study did not fall within the therapeutic range of omeprazole.

Can high-resolution peripheral quantitative computed tomography imaging of subchondral and cortical bone predict condylar fracture in Thoroughbred racehorses?

REASONS FOR PERFORMING STUDY: High-resolution 3D imaging may improve the prediction and/or early identification of condylar fractures of the distal metacarpus/tarsus and reduce the frequency of breakdown injury in racehorses. OBJECTIVES: To test the hypotheses that horses suffering condylar fractures have higher bone volume fraction (BV/TV) of the distal metacarpal epiphysis, greater subchondral bone thickness at the fracture site and higher second moment of inertia in the metacarpal midshaft as identified with high-resolution 3D imaging. STUDY DESIGN: Cross-sectional study using cadaver material. METHODS: Thoroughbreds that died on racetracks were grouped as: 1) horses with third metacarpal (McIII) fractures with a condylar component (cases, n = 13); 2) horses with no limb fracture (controls, n = 8); 3) horses with fractures in other bones or suspensory apparatus disruption (other fatal injuries, n = 16). The palmar condyles of McIII and the midshaft were examined with high resolution peripheral quantitative computed tomography (HR-pQCT). Statistical analysis included logistic regression and Spearman's correlation. RESULTS: There were no significant differences in BV/TV of distal McIII and second moment of inertia of the midshaft between cases and controls. Epiphyseal bone BV/TV was greater in injured limbs of horses with any fatal limb injury (Groups 1 and 3 combined) compared with controls (odds ratio = 1.20, 95% confidence interval 1.01-1.42, P = 0.034). An epiphyseal BV/TV>0.742 resulted in a sensitivity of 82.8% and specificity of 62.5% in identifying horses with fatal limb injury. In horses without condylar fracture, increased subchondral bone thickness was associated with palmar osteochondral disease lesions in the adjacent condyle (rs = 0.65, P<0.001). CONCLUSIONS: Increased BV/TV of the distal metacarpus may have some value for identifying horses at risk of any fatal breakdown injury but not metacarpal condylar fractures. Measurement of parasagittal groove subchondral bone thickness is complicated by adjacent palmar osteochondral disease lesions. Thus, high-resolution imaging of the distal metacarpus appears to have limited ability to identify horses at risk of condylar fractures.

Clinical significance of optic disc progression by topographic change analysis maps in glaucoma: an 8-year follow-up study.

Aim. To investigate the ability of Heidelberg Retina Tomograph (HRT3) Topographic Change Analysis (TCA) map to predict the subsequent development of clinical change, in patients with glaucoma. Materials. 61 eyes of 61 patients, which, from a retrospective review were defined as stable on optic nerve head (ONH) stereophotographs and visual field (VF), were enrolled in a prospective study. Eyes were classified as TCA-stable or TCA-progressed based on the TCA map. All patients underwent HRT3, VF, and ONH stereophotography at 9-12 months intervals. Clinical glaucoma progression was determined by masked assessment of ONH stereophotographs and VF Guided Progression Analysis. Results. The median (IQR) total HRT follow-up period was 8.1 (7.3, 9.1) years, which included a median retrospective and prospective follow-up time of 3.9 (3.1, 5.0) and 4.0 (3.5, 4.7) years, respectively. In the TCA-stable eyes, VF and/or photographic progression occurred in 5/13 (38.4%) eyes compared to 11/48 (22.9%) of the TCA-progressed eyes. There was no statistically significant association between TCA progression and clinically relevant (photographic and/or VF) progression (hazard ratio, 1.18; P = 0.762). The observed median time to clinical progression from enrollment was significantly shorter in the TCA-progressed group compared to the TCA-stable group (P = 0.04). Conclusion. Our results indicate that the commercially available TCA progression criteria do not adequately predict subsequent photographic and/or VF progression.

Patterns of scintigraphic uptake in the fetlock joint of Thoroughbred racehorses and the effect of increased radiopharmaceutical uptake in the distal metacarpal/tarsal condyle on performance.

REASONS FOR PERFORMING STUDY: The effect of palmar osteochondral disease lesions on performance of Thoroughbred (TB) racehorses is unclear. There is a need to describe patterns of radiopharmaceutical uptake (IRU) in fetlock joints of TB racehorses and to evaluate post scintigraphy performance. HYPOTHESES: IRU in the metacarpal (MC) and metatarsal (MT) condyles is more common than IRU in the parasagittal grooves and is associated with poorer post diagnosis performance than controls. METHODS: Location of IRU within the fetlock region was identified and graded subjectively in TB racehorses. Performance variables were determined from race records for horses with moderate/marked MC/MT condylar IRU (cases), other horses undergoing scintigraphy (scintigraphy controls) and age/sex matched controls from the last race in which a case participated (controls). Statistical analyses included quantile regression, Fisher's exact test, Kaplan-Meier survival curves, log-rank test and Cox regression. RESULTS: Metacarpal/MT condylar IRU was identified in 103/220 horses with only 3/220 having parasagittal IRU. Moderate/marked IRU was identified in the MC and MT condylar regions in 62 and 39 horses, respectively, with palmaromedial and plantarolateral IRU most common. Fore- and hindlimb cases had fewer starts, reduced earnings (P<0.001) and reduced earnings/start than controls respectively. Cases were more likely to return to racing later than controls following a rest period. Cases were older than scintigraphy controls. CONCLUSIONS: In TB racehorses presenting for lameness MC/MT condylar IRU is the most common abnormality identified within the fetlock joint. Racehorses with moderate/marked condylar IRU have a shortened racing career, are less successful than age/sex matched controls and are older than other racehorses presented for scintigraphy. POTENTIAL RELEVANCE: Overload of the MC/MT condyles is a common and significant problem in TB racehorses that is readily identified with scintigraphy. Scintigraphy of horses that are lame or performing poorly is less useful for screening for potential condylar fractures.

T-shaped malformation of the ventral colon in a Thoroughbred filly with colic.

A 4-month-old Thoroughbred filly presented for abdominal pain was diagnosed with a T-shaped malformation of the ventral colon at exploratory laparotomy. Following resection and anastomosis of the large colon, no further episodes of abdominal pain occurred during a 12-month follow-up. Acute dehiscence of the linea alba occurred as a complication of the initial laparotomy, but was successfully managed following additional surgical repair. T-shaped malformation of the ventral colon has not previously been reported and is considered a congenital malformation of mesocolon formation.

Medial collateral ligament desmitis of the distal interphalangeal joint in the hindlimb of a horse: treatment with cast immobilisation.

A 12-year-old show-jumping mare was presented for investigation of a chronic hindlimb lameness of 16 weeks duration. Perineural anaesthesia and ultrasonography localised the lesion to the medial collateral ligament of the distal interphalangeal joint of the left hindlimb. Treatment consisted of a heavily padded distal limb cast for 6 weeks, strict box rest and a strictly regulated hand walking program. Serial ultrasonographic examinations were performed throughout the rehabilitation period. Collateral ligament desmitis of the distal interphalangeal joint is a commonly diagnosed condition of the forelimb; however, hindlimb collateral ligament desmitis has been rarely reported. Ultrasonographic examination in this case was an invaluable diagnostic and follow-up tool. Immobilisation of the foot by means of a heavily padded distal limb cast allowed excellent healing of the ligament and is presented as a novel treatment for collateral ligament desmitis. At the time of writing the mare had returned to her previous level of exercise and was showing no signs of lameness.

Cataract surgery rates in Ontario, Canada, from 1992 to 2004: more surgeries with fewer ophthalmologists.

BACKGROUND: To evaluate trends in cataract surgeries in Ontario between 1992 and 2004. METHODS: A retrospective analysis of the number of cataract surgeries performed in Ontario from April 1992 to March 2005. The estimated prevalence of cataract and cataract surgeries per 1000 persons at risk was calculated. RESULTS: The number of cataract surgeries in Ontario increased from 44,943 in 1992 to 109,506 in 2004 (143.6%, 12.08% annual increase). The number of cataract surgeries per 1000 patients at risk of cataract increased from 64.6 in 1992 to 115.65 in 2004 (79%, 4.97% increase per year). This rate was strongly positively correlated with time and with the increase in the Ontario population (r = 0.920 and r = 0.922, respectively; p < 0.001). The number of ophthalmologists increased by 5.3% from 1992 to 1997 and then decreased by 2.9% by 2004. This change was not correlated with the cataract surgery rates (r = 0.475; p = 0.10). However, the number of ophthalmologists per million population decreased by 13.4% between 1992 and 2004. This number had a statistically negative correlation with cataract surgery rates (r = -0.757; p < 0.01). INTERPRETATION: There has been a significant increase in the number of cataract surgeries in Ontario despite a decrease in the number of ophthalmologists per million population.

Prospective study comparing lidocaine 2% jelly versus sub-Tenon's anaesthesia for trabeculectomy surgery.

AIMS: To compare the analgesic properties of lidocaine 2% jelly versus sub-Tenon's anaesthesia with lidocaine 2% without adrenaline (epinephrine) for trabeculectomy surgery. METHODS: A prospective randomised clinical trial. 59 consecutive patients scheduled for trabeculectomy at the Toronto Western Hospital were randomly assigned to topical unpreserved lidocaine 2% jelly or sub-Tenon's anaesthesia with 2% lidocaine. Both groups received a standardised sedative consisting of midazolam, fentanyl. and/or propofol. The visual analogue scale was utilised to measure intraoperative pain. Patient comfort, physician assessment of intraoperative patient compliance, volume of local anaesthetic used, need for supplemental anaesthesia, and any complications were recorded. The two groups were compared using the Student's t test. RESULTS: The sub-Tenon's anaesthesia group and the lidocaine 2% jelly group did not vary significantly in subjective pain score (18.3 (SD 16.2) v 19.8 (12.4) respectively, p = 0.739) and surgeons' satisfaction scale (3.6 (0.7) and 3.8 (0.6) respectively, p = 0.328). Four patients required additional anaesthesia, all of them in the sub-Tenon's group. CONCLUSION: Topical lidocaine 2% jelly is as effective as sub-Tenon's anaesthesia for pain control in patients undergoing trabeculectomy. Lidocaine 2% jelly is similar to sub-Tenon's anaesthesia in patient comfort and surgeon satisfaction.

The effect of simulated obstructive apnoea on intraocular pressure and pulsatile ocular blood flow in healthy young adults.

AIM: To investigate the effect of negative inspiratory effort, as generated by the Mueller manoeuvre, on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in healthy young adults. METHODS: Seven volunteers with no history of systemic or ocular disease were recruited (mean age 30.7 years, range 25-40 years, M/F: 4/3). After initial instruction and practice of the Mueller manoeuvre, baseline measurements of IOP and POBF were obtained for both eyes after 10 and 15 minutes of rest, respectively, in the supine position. Thereafter, the Mueller manoeuvre was performed creating a mouthpiece pressure of -20 cm H(2)O, for at least 15 seconds followed by a 5 minute rest. The manoeuvre was repeated with a mouthpiece pressure of -40 cm H(2)O. IOP and POBF were measured 5-15 seconds into the manoeuvre for both -20 cm H(2)O (M2A) and -40 cm H(2)O (M4A) and directly upon recovery (after two respiratory cycles) from each manoeuvre (M2B, M4B). Baseline measurements were compared using paired t test, whereas manoeuvre induced changes in IOP and POBF were analysed individually using repeated measures ANOVA with Student-Newman Keuls post hoc analyses. Linear regression analysis was used to investigate a dose-response effect. RESULTS: No significant differences were found between baseline measurements so they were subsequently pooled. There was a significant decrease in IOP for M2B (-9.2%, p<0.05), M4A (-13.8%, p<0.05), and M4B (-15.6%, p<0.05), relative to baseline. A dose-response relation was found for the effect of mouthpiece pressure on measurements 5-10 seconds into the manoeuvre (M2A and M4A, r = 0.54, p = 0.045). There was a trend of increased POBF relative to baseline for all measurements; however, significance was reached for M4B only (p = 0.039). CONCLUSION: It was shown that forced inspiratory efforts as generated by the Mueller manoeuvre are associated with a dose dependent decrease in IOP and a concomitant increase in pulsatile ocular blood flow.

Surgical repair of skull fractures in four horses using cuttable bone plates.

Three horses with severely comminuted, open facial bone fractures and one horse with a comminuted, open orbital rim fracture were referred for treatment. Severe facial bone asymmetry and epistaxis were apparent in all cases and subcutaneous emphysema was present in two, however physical and neurological examinations were otherwise normal. Radiography and endoscopy were of some use in assessing the degree of damage, although the true extent of the damage was more apparent at surgery. Surgical reduction of the fractures was recommended to maximise cosmetic and functional outcome. After surgical debridement and reduction of the fractures the bone fragments remained unstable and were not amenable to stabilisation with interfragmentary wires alone, so 2 mm cuttable bone plates were used to maintain fracture alignment. Screw migration occurred in three horses and in one of these horses the plate had to be removed. Other complications were minor and in all horses the fractures healed with good cosmetic and functional outcome. The use of cuttable bone plates should be considered as a reasonable alternative to inter-fragmentary wiring for unstable, comminuted fractures of the facial bones, even where fractures are open.

The long-term fluctuation of the visual field in stable glaucoma.

PURPOSE: To determine, in stable glaucoma, the characteristics of the between-examination variability of the visual field recorded with the Humphrey Field Analyser (HFA; Humphrey Systems, Dublin, CA) using the homogeneous, LF(Ho), and heterogeneous, LF(He), components of the long-term fluctuation (LF), thereby providing a technique for separating progressive loss from fluctuation in sensitivity. METHODS: The LF components were calculated using a two-factor analysis of variance (ANOVA) with replications and were determined between each pair of three successive HFA program 30-2 fields for each patient from two groups, each containing 30 patients with primary open-angle glaucoma. The interval between examinations for the first group was 6 to 9 months and for the second group was 3 weeks. RESULTS: The group mean values for LF(Ho) ranged from 1.50 to 2.19 dB and for LF(He) from 1.70 to 2.05 dB. The average difference between examinations was within +/-0.35 dB for each component, and the 95% limits of agreement for the two groups, respectively, were +/- 2.31 and +/- 2.39 dB for the LF(Ho) and +/- 2.36 and +/- 2.09 dB for the LF(He). The estimate of the 90% confidence limit for the LF(Ho) was 3.30 dB and for the LF(He), 3.60 dB. Little relationship was present between the LF components and the modulus differences in mean deviation (MD), the corrected pattern SD (CPSD), or the mean MD, mean short-term fluctuation, and mean CPSD, of the two fields. CONCLUSIONS: Estimation of the LF components and of the corresponding confidence limits yields an expression of the normal between-examination variability of two consecutive fields that can be used as a reliability index. A value outside the confidence limits indicates the necessity for a confirmatory follow-up field.

Long-term results of transscleral Nd:YAG cyclophotocoagulation for refractory glaucoma postpenetrating keratoplasty.

PURPOSE: To determine the effects of noncontact transscleral Nd:YAG cyclophotocoagulation (NCTY) in the treatment of refractory glaucoma postpenetrating keratoplasty (PKP) with respect to intraocular pressure (IOP), corneal graft survival, and reduction of glaucoma medications. METHODS: The records of all patients treated with NCTY for refractory glaucoma after PKP at the authors' institution over an 11-year interval were reviewed. The LASAG noncontact Nd:YAG laser (Lasag AG; Thun, Switzerland) was used. Approximately 40 laser applications were delivered per eye. Visual acuity, IOP, glaucoma medications, and corneal graft clarity were evaluated. RESULTS: Fifty-two eyes met the inclusion criterion. The mean pretreatment IOP was 38.7+/-11.9 mm Hg. The mean posttreatment IOP was 15.8+/-9.7 mm Hg. From life table analysis, the probability of having a posttreatment IOP of 21 mm Hg or less with or without medication was 70% at 1 year and 63% at 5 years. The probability of a graft remaining clear was 79% at 1 year and 56% at 5 years. In 85% of patients the visual acuity remained stable, in 11% the visual acuity improved, and in 4% the visual acuity deteriorated after treatment. One patient developed hypotony. Twenty patients (36.5%) were able to discontinue one or more glaucoma medications posttreatment. CONCLUSION: In this group of patients with PKP glaucoma, NCTY effectively lowered IOP over the long term, with 36.5% of patients discontinuing one or more glaucoma medications. There was, however, a significant incidence of graft failure at 5 years.

The genetic aspects of adult-onset glaucoma: a perspective from the Greater Toronto area.

BACKGROUND: The myocilin gene is the first glaucoma gene to be associated with primary open-angle glaucoma (POAG). The hereditary subset of POAG and the role of the myocilin gene in our population are not clearly defined. Identification of cases of hereditary glaucoma and a better appreciation of the role of the myocilin gene may allow earlier diagnosis of the disease and optimize management of those at risk for glaucoma. METHODS: Patients were recruited from university glaucoma practices in the Greater Toronto area from 1996 to 1998. Pedigree analysis and DNA banking were performed for each participant. Mutational analysis of the myocilin gene by means of single-strand conformation polymorphism analysis and direct sequencing was completed for 140 probands with POAG of diverse ethnic background. RESULTS: A total of 103 patients (55.7%) had a family history of glaucoma. Disease-causing mutations of the myocilin gene were observed in 7 (5.0%) of the 140 probands, which accounted for 6.5% (5/77) of the familial cases. Most mutations were associated with familial disease, which implies a 50% risk of transmission of a high-risk factor for glaucoma. INTERPRETATION: The hereditary subset of POAG is significant, and heritable glaucoma should always be suspected. In spite of the diversity of the ethnic background of our subjects, the observed prevalence of myocilin gene mutations was comparable to that previously reported, and such mutations do not appear to spare any ethnic group.

Interobserver agreement of Heidelberg retina tomograph parameters.

PURPOSE: To measure the interobserver agreement of Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) parameters as a result of different observers' contour line placement. METHODS: The optic nerve heads of 50 patients with glaucoma were imaged with the HRT. Five observers traced each disc margin with a contour line. Each observer was masked to the contour line tracings of the other observers, and there was no formal discussion as to where to place the contour line. The following stereometric parameters were calculated for each image for each observer: disc area, mean height of contour, cup shape, rim volume using the standard reference plane from software version 1.11, rim volume using a reference plane of 320 microns below the retinal plane, and volume above curved surface. Agreement between the five observers was tested for each parameter using intraclass correlation coefficients (ICCs). RESULTS: Interobserver agreement between the five observers was substantial for both rim volumes (ICC = 0.73) and for disc area (ICC = 0.67). Agreement was almost perfect for mean height of contour (ICC = 0.94), cup shape (ICC = 0.92), and volume above curved surface (ICC = 0.83). CONCLUSION: The interobserver agreement for the HRT parameters was substantial to almost perfect, indicating that the HRT results as defined by the five observers were interchangeable.

Is a tight patch necessary after trabeculectomy?

AIMS: To determine if post-trabeculectomy patching reduces the prevalence of shallow/flat anterior chambers and pain. METHODS: 435 eyes were prospectively randomised to either a double patch with tape or no patch with tape group. RESULTS: There was no statistically significant difference in flat or shallow anterior chamber rates or pain symptoms between the patch and no patch groups. CONCLUSION: There is no benefit to patching the post-trabeculectomy eye.