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.

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.

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.

Functional analyses of two newly identified PITX2 mutants reveal a novel molecular mechanism for Axenfeld-Rieger syndrome.

The specific role of PITX2 in the pathogenesis of anterior segment dysgenesis has yet to be clearly defined. We provide here new insight into PITX2 pathogenesis through mutational and functional analyses. Three PITX2 mutations were found in a screen of 38 unrelated individuals affected with anterior segment anomalies (8%). All three mutations were found among the 21 individuals affected with Axenfeld-Rieger syndrome (ARS). We have identified two novel mutations, a valine-->leucine (V45L) missense mutation at position 45 within the PITX2 homeodomain, and a seven amino acid duplication (7aaDup) of residues 6-12 of the homeodomain. DNA-binding studies of the two mutant PITX2 proteins demonstrated a <10-fold reduction in the DNA-binding activity of the V45L mutant, and a >100-fold reduction in activity of the 7aaDup mutant. Luciferase reporter assays showed a >200% increase in PITX2 transactivation activity of the V45L mutant, while the 7aaDup mutant was unable to transactivate at detectable levels. Our analyses of the V45L PITX2 mutant reveal that the DNA-binding domain of PITX2 can influence transactivation activity independently of DNA binding. Furthermore, our findings expand the hypothesis that the amount of residual PITX2 activity underlies the variable severity of ocular phenotypes that result from PITX2 mutation. For the first time, we present evidence that increased PITX2 activity may underlie the severe ARS ocular phenotype. We conclude that increased activity of one PITX2 allele may be as physiologically disruptive as a mutation that nullifies a PITX2 allele, with either condition resulting in ARS.

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.

Efficacy of brimonidine 0.2% as adjunctive therapy for patients with glaucoma inadequately controlled with otherwise maximal medical therapy.

PURPOSE: To evaluate the clinical efficacy and tolerability of brimonidine tartrate 0.2% twice daily as adjunctive therapy for glaucoma patients inadequately controlled with otherwise maximal tolerated medical therapy. DESIGN: Retrospective, noncomparative, case series. PARTICIPANTS: Ninety-six patients were identified from the authors' tertiary glaucoma practice who were treated with brimonidine. Their glaucoma was uncontrolled despite maximal tolerated medical therapy before receiving brimonidine, and some had previously undergone argon laser trabeculoplasty or filtration surgery. The patients were subdivided according to their glaucoma diagnosis: open-angle (OAG), angle-closure (ACG), mixed mechanism, and congenital glaucoma. Both the short- (about 2 weeks) and long-term results were evaluated. Twenty-two patients were excluded because additional medication changes were made at the time of introduction of brimonidine. INTERVENTION: Brimonidine was added to the existing regimen of glaucoma medication. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) was recorded at all follow-up dates, together with visual field examination and optic disc evaluation twice yearly. RESULTS: There were 44 OAG, 20 ACG, 6 mixed mechanism, and 4 congenital glaucoma patients. Mean pretreatment IOP, mean short-term post-treatment IOP, and mean short-term IOP reduction (percentage) were 23.10 +/- 5.21 mmHg, 18.49 +/- 4.77 mmHg, and 4.6 mmHg (20%) for OAG; 22.80 +/- 5.70 mmHg, 18.65 +/- 5.75 mmHg, and 4.15 mmHg (18%) for ACG; 25.00 +/- 10.32 mmHg, 21.00 +/- 12.12 mmHg, and 4.0 mmHg (16%) for mixed mechanism; and 26.00 +/- 4.97 mmHg, 17.75 +/- 4.57 mmHg, and 8.25 mmHg (32%) for congenital glaucoma, respectively. Mean long-term follow-up was 204 days for OAG and 213 days for ACG. Of the initially controlled OAG and ACG patients, at 3 months 96% and 100%, at 6 months 80% and 77%, and at 9 months 58% and 44%, respectively, were still controlled. Six patients discontinued brimonidine, three of these owing to allergy. CONCLUSION: As adjunctive therapy, brimonidine achieved a short-term IOP reduction of 16%-32% in this patient population; 77%-80% of initially controlled patients were still controlled after 6 months. Brimonidine was well tolerated.

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.

Agreement in assessing glaucomatous discs in a clinical teaching setting with stereoscopic disc photographs, planimetry, and laser scanning tomography.

PURPOSE: Agreement between three observers--two recently trained fellows and their supervisor--was measured using estimations of cup/disc ratio from stereoscopic optic nerve head photographs and planimetric measurements of cup/disc ratio. Agreement between the clinicians' planimetric measurements of cup/disc ratio and laser scanning tomographic measurements of cup/disc ratio also was assessed. METHODS: From 16 stereoscopic optic nerve head photographs of 16 subjects, the three observers performed clinical estimations of horizontal and vertical cup/disc ratios and planimetric measurements of cup/disc ratios. Interobserver agreement was measured using intraclass correlation coefficients (ICCs). Agreement between the planimetric cup/disc ratios and laser scanning tomographic cup/disc ratios obtained with the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) also was measured using ICCs. The difference between the planimetric and HRT cup/disc ratios was calculated. RESULTS: The agreement between observers for clinical estimations from stereoscopic optic nerve head photographs (ICC = 0.74 horizontally and 0.83 vertically) was substantial. Agreement between the observers' planimetric measurements of cup/disc ratio was substantial (ICC = 0.79). Agreement between HRT cup/disc ratio and each observer's planimetric cup/disc ratio was moderate (ICC = 0.57-0.65), with large confidence intervals. The cup/disc ratio measured with HRT was an average of 0.07 to 0.11 larger than the planimetric cup/disc ratio. CONCLUSION: Substantial agreement between observers can be achieved when estimating cup/disc ratio with stereoscopic optic nerve head photographs and with planimetric measurements of cup/disc ratios, provided there is a standard protocol and sufficient training period. Good agreement is critical in a teaching institution to ensure accurate follow-up care of patients with glaucoma, especially if patients are examined by different clinicians. Laser scanning tomography is a more repeatable and objective method, which may provide further standardization of optic nerve head assessments. Future studies will determine the reference plane that optimizes agreement between the HRT findings and each clinician's estimations.

Analysis of myocilin mutations in 1703 glaucoma patients from five different populations.

A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.

Retinitis pigmentosa, nanophthalmos, and optic disc drusen: a case report.

OBJECTIVE: Although the associations of retinitis pigmentosa (RP) with nanophthalmos/microphthalmos and RP with optic disc drusen have previously been recognized, the concurrence of all three features, as far as the authors are aware, has not previously been reported. DESIGN: Case report. RESULTS: The authors report a sporadic case of nanophthalmos, RP, and optic nerve drusen with the additional complication of chronic angle closure glaucoma. CONCLUSIONS: Visual loss may be secondary to the complications of nanophthalmos, RP, or optic nerve drusen. Chronic angle closure may be caused by choroidal effusion with serous retinal detachment, which may, in turn, cause a pseudo-RP picture. It is therefore important to recognize the possible association of true RP with nanophthalmos as a cause for visual deterioration.

Ultrasound biomicroscopic quantitative analysis of light-dark changes associated with pupillary block.

PURPOSE: To quantitatively analyze the changes in anterior chamber angle and iris configuration induced by varying illumination in patients with narrow angles and pupillary block. METHODS: Twenty-four eyes of 24 patients with pupillary block (mean age, 52.5 years) had ultrasound biomicroscopic images of the angle and iris structures obtained superiorly, nasally, inferiorly, and temporally. Images were performed in the light and the dark. We measured the angle opening distance, iris thickness, iris chord length, iris-lens touch, and iris curvature. RESULTS: Changes in iris and angle configuration occurred within a few seconds of a change in lighting. The mean dark measurements were statistically significantly less than the mean light measurements for angle opening distance (96 +/- 18 vs 185 +/- 26 microm, P = .0001), iris chord length (2,505 +/- 61 vs 3,001 +/- 69 microm, P = .0001), and iris-lens touch (350 +/- 20 vs 693 +/- 35 microm, P = .0001). The mean dark measurements were statistically significantly greater than the mean light measurements for iris thickness at 500 microm from the scleral spur (367 +/- 10 vs 307 +/- 25 microm, P = .0001), and 1,500 microm from the scleral spur (404 +/- 14 vs 347 +/- 12 microm, P = .0001). Iris curvature in all four quadrants was statistically significantly greater in the dark than the light. CONCLUSIONS: This study quantitatively confirms that angle narrowing in the dark in eyes with pupillary block is associated with iris shortening, increased iris thickness, and increased iris convexity. Iris-lens touch is relatively small in pupillary block and decreases with dilation. Angle narrowing with dilation is not related to increased iris-lens touch and occurs promptly without requiring time for aqueous pressure buildup behind the iris.

Imaging zonular abnormalities using ultrasound biomicroscopy.

OBJECTIVES: To evaluate the use of ultrasound biomicroscopy (UBM) in detecting ciliary zonular defects and to describe the UBM signs of such defects. METHODS: Eighteen eyes of 18 patients with clinically suspected zonular abnormalities were evaluated using UBM. Predisposing factors included pseudoexfoliation, congenital spherophakia, surgical procedure, trauma, and the Marfan syndrome. RESULTS: Of 18 eyes, 11 showed UBM evidence of missing zonules and 11 showed evidence of zonular stretch. Four of the 18 eyes had both missing and stretched zonular fibers. All of the eyes examined showed increased lenticular sphericity in the area of zonular disorder. Nine eyes showed ciliary body flattening. Pupillary block was seen in 5 patients, and angle crowding due to direct iridal rotation was noted in 3. CONCLUSIONS: Ultrasound biomicroscopy can detect zonular loss and stretching directly. Increased lenticular sphericity and ciliary body flattening are signs of zonular defects. Angle closure mechanisms include pupillary block and direct iridal rotation.