Structure-function correlations of glaucoma in Filipinos

Introduction@#To determine the structure-function correlations of glaucoma in Filipinos using the average peripapillary retinal nerve fiber layer (RNFL) thickness and rim area (RA) of the spectral-domain optical coherence tomography (SD-OCT) and mean defect (MD), pattern standard deviation (PSD), and visual field (VF) clusters of standard automated perimetry (SAP)@*Methods@#Consecutive tests consisting of SD-OCT, SAP, and disc photos were reviewed and selected based on abnormalities in VFs or OCTs or both. Each set of tests was classified as to VF defect type and severity. Mean threshold of VF clusters, MD, and PSD were correlated with average and sectoral RNFL thicknesses and RA. @*Results@#One hundred eighty-six (168) eyes of 121 patients with mean age of 60.2 ± 14.7 years had an average MD, PSD, RNFL thickness, RA of -9.5 ± 8.5 dB, 5.4 ± 3.3 dB, 75.9 ± 15.9 μm, and 0.9 ± 0.4 mm2, respectively. Among VF tests, 23.1% were normal, 16.5% had early, 9.1% moderate, 12.4% advanced, and 8.3% severe glaucoma damage. Most common VF defect types were central islands, combined, and paracentral (16.5%, 14.4%, and 12.2%, respectively). The most commonly affected RNFL segments were inferior, followed by superior, and combined superior and inferior (51.2%, 47.1, and 34%, respectively). Among the OCT parameters, RNFL thickness and RA were strongly correlated (p<0.0001). Between the VF and OCT parameters, the strongest correlation was between the clusters of superior VF defects and the 6-8 o’clock RNFL thinning, followed by the inferior VF defects and the 12-1 o’clock RNFL thinning. Inferior RNFL thinning was strongly correlated with MD and PSD. @*Conclusion@#Among Filipino glaucomatous eyes monitored with SD-OCT and SAP, correlation was strongest between the superior VF defects and the infero-temporal RNFL thinning.

Andragogic principles in case-based discussion among medical interns in a tertiary hospital

Background@#Andragogy, the theory of adult learning is relevant to medical education especially in the clinical internship learning context. It focuses on the students, faculty, and patients interacting together while developing competencies as future practitioners. Medical interns are active adult learners, enhancing their development of knowledge, skills, and positive attitudes, and pursuing professionalism as they participate in case-based discussions (CBD).@*Objectives@#The study sought to identify the basic principles of andragogy while medical interns participate in case-based discussions including the end-of-course satisfaction. It also determined the selected demographic factors associated with the andragogic principles. @*Methodology@#Respondents included 80 interns by convenience sampling who rotated at the Department of Ophthalmology and Visual Sciences in a tertiary referral hospital. The study used a combination of descriptive quantitative and qualitative research design. A valid instrument using the Adult Learning Principles Design Elements Questionnaire (ALPDEQ) was used to measure the medical intern's andragogic orientation as well as end-of-course satisfaction. A direct, non-participant observation of case-based discussions conducted at the department was done by the researcher and research associate. @*Results and Conclusion@#The occurrence of andragogic principles specifically motivation, experience, need to know, readiness, and self-directedness was observed during the conduct of case-based discussion. There was no association between principles of andragogy and demographic factors such as age, gender, civil status, medical school, preparatory medical course, and place of origin. CBD is an effective learning strategy, which provides medical interns adequate venues to be self-directed and apply the principles of andragogy in a workplace-based setting.

Should slow release Glaucoma Medications replace eye drops?

@#Instilling glaucoma eye drops has been the mainstay in glaucoma management for many years, be it as initial treatment or as adjunct to laser or filtering surgeries. There are different classes of glaucoma eye drops, with different mechanisms of action to lower the intraocular pressure (IOP), either by improving the outflow facility or by suppressing the aqueous production, singly or as combination therapy. Many of these eye drops can lower the IOP by as much as 35% when given either once or twice a day. Successful treatment outcomes for chronic diseases such as glaucoma, however, require daily use of glaucoma eye drops to minimize disease progression.

Fluorophotometric measurements of aqueous-humor flow in post-YAG laser iridotomy for acute angle closure

Objective@#This study compared the rates of aqueous-humor flow and trabecular outflow in eyes that had undergone YAG laser iridotomy (LI) for primary-acute-angleclosure (PAC) attack and primary-angle-closure suspect (PACS).@*Methods@#Patients who had PAC attack in one eye and narrow occludable angles (PACS) in the other eye that had undergone YAG LI were recruited. All underwent complete ophthalmologic examination including gonioscopy, ultrasonic pachymetry, A scan, and fluorophotometry to determine the rate of aqueous-humor flow. The Goldmann equation was used to compute the outflow facility using the values of aqueous flow and intraocular pressure (IOP).@*Results@#Fifty eyes of 25 patients were included, 25 of which had PAC attack and 25 were PACS. The central corneal thickness (CCT), anterior-chamber depth, and anterior-chamber volume of the 2 groups were comparable. PAC-attack eyes had significantly higher IOP (18.4 mm Hg) than the PACS (14.12 mm Hg) (p = 0.001). The mean rate of aqueous flow was 2.50 ± 0.94 µL/min and 2.89 ± 1.17 µL/min in the PAC and PACS respectively (p = 0.20). The mean aqueous-outflow facility was 0.29 ± 0.18 µL/min and 0.59 ± 0.37 µL/min respectively (p = 0.0008).@*Conclusion@#A significantly lower aqueous-outflow facility was demonstrated by fluorophotometry among eyes with PAC. Despite the anatomically open angles, they continued to have higher IOPs.

Predictors for failure of primary trabeculectomy

Objective@#This study determined the success and failure rates of primary trabeculectomy in a university hospital and identified the factors predictive of failure. A retrospective, nested case-control study was conducted involving primary trabeculectomies done in a university hospital from January 2005 to December 2007 with at least one year of follow-up. Depending on the outcomes, patients were classified as cases or controls. Cases were those with failed trabeculectomies defined as intraocular pressure (IOP) >21 mm Hg in all patients and >15 mm Hg in advanced glaucoma at 1 year follow-up. Eyes requiring further glaucoma surgery were also considered failure. Controls were those with successful trabeculectomies defined as IOP <21 mm Hg in all patients and <16 mm Hg in advanced glaucoma, and at least 20% reduction from the presenting IOP and on no more than 2 antiglaucoma medications at one-year follow-up. Preoperative, intraoperative, and postoperative variables were collected and analyzed by bivariate analyses and multiple logistic regression.@*Results@#At one-year follow-up, the success rate was 79.8%. Age at the time of surgery, gender, eye laterality, presence of diabetes, history of intraocular surgery, previous laser treatment, maximum IOP, glaucoma diagnosis, and total number and duration of preoperative antiglaucoma medications were not shown to affect outcome of surgery. Variations in the intraoperative technique, including conjunctival flap approach, location and shape of the scleral flap, suturing technique, and surgeon’s competency were not associated with outcome. Postoperative IOP at 1 month, 3 months, and 6 months were predictors of successful outcome at 1 year. Postoperative subconjunctival 5FU injection, bleb manipulation, and laser suture lysis did not alter outcome.@*Conclusion@#Early postoperative IOP at 1 month is already predictive of the outcome of primary trabeculectomy at 1 year.

Correlation of structure and function in glaucoma

Objective@#This study assessed the relationship of two structural tests, optic-disc photography and optical coherence tomography (OCT), and a functional test, standard achromatic perimetry (SAP), in the diagnosis of glaucoma.@*Methods@#A retrospective review of charts from the database of a private glaucoma specialist and the glaucoma clinic of a tertiary hospital was done. The participants were longitudinally evaluated and had comprehensive eye examination, imaging, and functional testing. Optic-disc photographs, OCTs, and SAPs were interpreted and evaluated separately, and then correlated with each other by two glaucoma experts working individually. Sensitivities, specificities, and predictive values were obtained for each diagnostic test and in combination. Kappa statistics were used for interobserver agreement.@*Results@#Three hundred sixty-seven eyes of 188 patients were included in the study. Fifty-eight patients were diagnosed as normal, 130 had glaucoma. OCT had the highest sensitivity and specificity at 70.7% and 76.6%, followed by SAP at 72.4% and 53.5% respectively. Optic-disc photos had the lowest sensitivity and specificity at 55.8% and 54.4% respectively, and the lowest interobserver agreement (kappa = 0.50-0.61). The predictive values of the 3 tests increased to 82% with good interobserver agreement (kappa = 0.68-0.78) when correlated with each other.@*Conclusion@#The correlation of structural and functional tests increased the accuracy of diagnosing glaucoma. These examinations offered complementary information and, when used in conjunction with comprehensive clinical evaluation, guided the clinician in the proper management of patients with glaucoma.

Reliability analyses of the GDx nerve-fiber analyzer

Objectives: The scanning laser polarimetry, exemplified by the GDx 400 (Laser Diagnostic Technologies, San Diego, CA, USA) nerve-fiber analyzer, allows noninvasive quantitative assessment of the retinal nerve-fiber layer. This study determined the reliability of the GDx 400 in taking repeat measurements by different operators and at different sessions in a sample of normal and glaucoma patients Methods: Patients with and without glaucoma underwent a complete eye evaluation, automated achromatic perimetry, scanning laser polarimetry, and optic-disc photography. Retinal nerve-fiber layer (RNFL) measurements were obtained for each group of patients by two trained operators who were masked as to the status of the study eye. Four measurements were obtained for each study eye in the same session and in another session. Reliability measures using intraclass correlation coefficient of five preselected GDx parameters were obtained Results: The study recruited 355 patients (171 normal, 184 glaucomatous) ages 30 to 78 years. Intraclass correlation coefficients within operator same session (0.84-0.95), within operator different sessions (0.78-0.93), between operators same session (0.79-0.94), and between operators different sessions (0.80-0.94) were excellent. The reliability measures for the second session (0.79-0.94) were higher than for the first session (0.79-0.87) even for measurements taken by the same operator Conclusion: The GDx 400 nerve-fiber analyzer has good reliability measures and can be used to monitor changes in the RNFL thickness over time. Change in measurements exceeding 20 percent from baseline should be considered as possible progression. (Author)