Perceived usefulness and ease of use of fundoscopy by medical students: a randomised crossover trial of six technologies (eFOCUS 1).

BACKGROUND: Fundoscopy outside ophthalmology is in decline, and the technical demands of the traditional direct ophthalmoscope examination are likely contributing. Alternative fundoscopy technologies are increasingly available, yet valid comparisons between fundoscopy technologies are lacking. We aimed to assess medical students' perceptions of usefulness and ease of use of traditional and contemporary fundus-viewing technologies including smartphone fundoscopy. METHODS: One hundred forty-six second-year medical students participated in a cross-sectional, randomised, cross-over study of fundoscopy methods. Medical students completed small group training sessions using six current fundoscopy technologies including: a non-mydriatic fundus camera; two types of direct fundoscopy; and three types of smartphone fundoscopy. A novel survey of perceived usefulness and ease of use was then completed by students. RESULTS: Repeated-measures ANOVA found students rated both the perceived usefulness (p< 0.001) and ease of use (p< 0.001) of smartphone fundoscopy significantly higher than both the non-mydriatic camera and direct fundoscopy. CONCLUSIONS: Smartphone fundoscopy was found to be significantly more useful and easier to use than other modalities. Educators should optimise student access to novel fundoscopy technologies such as smartphone fundoscopy which may mitigate the technical challenges of fundoscopy and reinvigorate use of this valuable clinical examination.

Differentiation of Autoimmune Pancreatitis from Pancreatic Cancer Remains Challenging.

BACKGROUND: Autoimmune pancreatitis (AIP) is an uncommon form of chronic pancreatitis. Whilst being corticosteroid responsive, AIP often masquerades radiologically as pancreatic neoplasia. Our aim is to appraise demographic, radiological and histological features in our cohort in order to differentiate AIP from pancreatic malignancy. METHODS: Clinical, biochemical, histological and radiological details of all AIP patients 1997-2016 were analysed. The initial imaging was re-reviewed according to international guidelines by three blinded independent radiologists to evaluate features associated with autoimmune pancreatitis and pancreatic cancer. RESULTS: There were a total of 45 patients: 25 in type 1 (55.5%), 14 type 2 (31.1%) and 6 AIP otherwise not specified (13.3%). The median (IQR) age was 57 (51-70) years. Thirty patients (66.6%) were male. Twenty-six patients (57.8%) had resection for suspected malignancy and one for symptomatic chronic pancreatitis. Three had histologically proven malignancy with concurrent AIP. Two patients died from recurrent pancreatic cancer following resection. Multidisciplinary team review based on radiology and clinical history dictated management. Resected patients (vs. non-resected group) were older (64 vs. 53, p = 0.003) and more frequently had co-existing autoimmune pathologies (22.2 vs. 55.6%, p = 0.022). Resected patients also presented with less classical radiological features of AIP, which are halo sign (0/25 vs. 3/17, p = 0.029) and loss of pancreatic clefts (18/25 vs. 17/17, p = 0.017). There were no differences in demographic features other than age. CONCLUSION: Despite international guidelines for diagnosing AIP, differentiation from pancreatic cancer remains challenging. Resection remains an important treatment option in suspected cancer or where conservative treatment fails.

Can acoustic radiation force imaging of the liver and spleen predict the presence of gastroesophageal varices?

AIM: To determine whether acoustic radiation force imaging (ARFI) of the liver/spleen could be used in patients with cirrhosis to predict the presence of gastroesophageal varices (GOVs). MATERIALS AND METHODS: Fifty-eight patients with cirrhosis who were undergoing 6-monthly ultrasound examinations for hepatoma surveillance and who were due to have oesophagogastroduodenoscopy (OGD) within 6 months of their ultrasound were recruited. During routine ultrasound, the patient's liver and spleen were also assessed using ARFI. Other clinical parameters (platelet count, spleen size, and transient elastography measurements) were also collected. Logistic regression was used to determine which variables were significantly associated with presence or absence of varices univariably and multivariably RESULTS: Fourteen patients (24%) had GOVs. Patients with GOVs had higher ARFI measurements in the liver and spleen than patients without GOVs (liver: 2.39 versus 2.13, spleen: 2.89 versus 2.82), but these results were not statistically significant (odds ratio=1.75, 95% confidence interval [CI]=0.82, 3.91 and odds ratio=1.12, 95% CI=0.33, 3.97, respectively). The platelet/splenic ratio, in comparison, was associated with the presence or absence of GOVs in multivariate analysis (odds ratio=0.32, 95% CI=0.008, 0.91). CONCLUSION: Although patients with GOVs had overall higher ARFI liver and spleen results, this was not statistically significant. As such, ARFI cannot yet replace OGD in predicting GOVs in this patient group.

Circumferential resection margin (CRM) positivity after MRI assessment and adjuvant treatment in 189 patients undergoing rectal cancer resection.

PURPOSE: The management of rectal cancer relies on accurate MRI staging. Multi-modal treatments can downstage rectal cancer prior to surgery and may have an effect on MRI accuracy. We aim to correlate the findings of MRI staging of rectal cancer with histological analysis, the effect of neoadjuvant therapy on this and the implications of circumferential resection margin (CRM) positivity following neoadjuvant therapy. METHODS: An analysis of histological data and radiological staging of all cases of rectal cancer in a single centre between 2006 and 2011 were conducted. RESULTS: Two hundred forty-one patients had histologically proved rectal cancer during the study period. One hundred eighty-two patients underwent resection. Median age was 66.6 years, and male to female ratio was 13:5. R1 resection rate was 11.1%. MRI assessments of the circumferential resection margin in patients without neoadjuvant radiotherapy were 93.6 and 88.1% in patients who underwent neoadjuvant radiotherapy. Eighteen patients had predicted positive margins following chemoradiotherapy, of which 38.9% had an involved CRM on histological analysis. CONCLUSIONS: MRI assessment of the circumferential resection margin in rectal cancer is associated with high accuracy. Neoadjuvant chemoradiotherapy has a detrimental effect on this accuracy, although accuracy remains high. In the presence of persistently predicted positive margins, complete resection remains achievable but may necessitate a more radical approach to resection.

Automated analysis of cellular change in histological sections.

An image analysis computer has been used to count and measure goblet cells in the epithelium of the bronchiolar tree of rats exposed to sulfur dioxide vapor. A technique was developed which enabled a bioassay of the irritant effects of the gas.

Racial Differences in Accepting Pegfilgrastim Onpro Kit (On-Body Injector) Use Among Cancer Patients.

Background: 1.1.Neulasta Onpro kit eliminates need for additional clinic visit after chemotherapy. Given the racially diverse population in our institution, we investigated acceptance of Onpro kit among patients on chemotherapy. Research Design and Methods: 1.2.Single-institution, retrospective review conducted in patients with GI tumors who received Onpro kit within 1 hour of completion of systemic chemotherapy from Jan 2014 through Jan 2018. Clinic/nursing notes and pharmacy records were reviewed to identify patients who refused Onpro kit and to discern reasons for refusal, including racial reason. Results: 1.3.Total 238 orders for kit were voided amongst 68 patients (Caucasian 41; African American 7; Spanish 3; Asian 17). Overall, 15/68 patients refused kit (22%) of these 87% were Asian. The reasons for refusal included dislike of bulky attachment to skin, request to place kit on stomach instead of arm, trepidation over unwitnessed administration of drug, fear of reaction, disposal at home, fear of pain, lack of confirmation of proper dose administration, and need for MRI. Conclusions: 1.4.While Onpro kit is an attractive alternative, 22% of patients with voided orders, mainly of Asian race, declined its application. We believe the current study represents the first look at important racial differences in accepting Onpro kit. Consideration of patients' cultural heritage, race, ethnicity and education may facilitate communication between physicians and patients to achieve optimal cancer care.

When does the 'learning curve' of innovative interventions become questionable practice?

Demand for less invasive surgical intervention has increased in recent years resulting in surgeons occasionally being pressurised into adopting new techniques before evidence of safety and efficacy has been established. Unlike pharmaceutical research, most innovative surgical procedures enter surgical practice without regulatory oversight. This anomaly was recently highlighted in the 'Bristol Report' resulting in a recommendation that unproven therapies or surgical techniques be subjected to ethical overview or independent oversight. When a novel technique is introduced, the surgeon will find himself/herself gaining proficiency and experience on suitable patients. Hence the surgeon embarks on a 'learning curve'. A learning curve can be defined as a graphic representation showing the relationship between experience with a procedure and outcome. Studies demonstrate that learning curves generally 'flatten out' as experience increases, resulting in fewer complications and less of a need to convert to the standard procedure. In addition to lack of regulatory oversight, it is this learning curve that gives rise to many ethical and legal dilemmas. This paper considers the ethical issues relating to a surgeon's candour and clinical equipoise, the legal standard of care in a negligence action and the ethical and legal implications regarding risk disclosure during informed consent. The paper concludes by considering a more patient centred approach where new and innovative therapies are being considered in order to ensure good medical practice and avoid litigation for allegations of negligence or breach of human rights.

Measured and perceived indices of fluid balance in professional athletes. The use and impact of hydration assessment strategies.

BACKGROUND: To determine athletes perceived and measured indices of fluid balance during training and the influence of hydration strategy use on these parameters. METHODS: Thirty-three professional rugby union players completed a 120 minute training session in hot conditions (35°C, 40% relative humidity). Pre-training hydration status, sweat loss, fluid intake and changes in body mass (BM) were obtained. The use of hydration assessment techniques and players perceptions of fluid intake and sweat loss were obtained via a questionnaire. RESULTS: The majority of players (78%) used urine colour to determine pre-training hydration status but the use of hydration assessment techniques did not influence pre-training hydration status (1.025 ± 0.005 vs. 1.023 ± 0.013 g.ml-1, P = .811). Players underestimated sweat loss (73 ± 17%) to a greater extent than fluid intake (37 ± 28%) which resulted in players perceiving they were in positive fluid balance (0.5 ± 0.8% BM) rather than the measured negative fluid balance (-1.0 ± 0.7% BM). Forty-eight percent of players used hydration monitoring strategies during exercise but no player used changes in BM to help guide fluid replacement. CONCLUSION: Players have difficulty perceiving fluid intake and sweat loss during training. However, the use of hydration monitoring techniques did not affect fluid balance before or during training.

Meta-analysis of randomised controlled trials comparing latanoprost with brimonidine in the treatment of open-angle glaucoma, ocular hypertension or normal-tension glaucoma.

AIM: To compare the efficacy and tolerability of latanoprost versus brimonidine in the treatment of open-angle glaucoma, ocular hypertension or normal-tension glaucoma. METHOD: Systematic review of randomised controlled trials comparing latanoprost and brimondine, identified by searches including Medline, Embase and Cochrane Controlled Trials Register. Two reviewers independently assessed trials for eligibility and quality and extracted data. Data were synthesised (random effects model) and expressed as the absolute mean intraocular pressure (IOP) reduction difference from baseline to end point for efficacy and relative risk for adverse events. Subgroup analysis and regression were used to explore heterogeneity according to patient characteristics, trial design and quality. RESULTS: 15 publications reporting on 14 trials (1784 participants) were included for meta-analysis. IOP reduction favoured latanoprost (weighted mean difference (WMD) = 1.10 mm Hg (95% confidence interval (CI) 0.57 to 1.63)). Significant heterogeneity was present (chi(2)(13) = 38.29, p = 0.001, I(2) = 66.0%). Subgroup analysis showed greater WMD for studies where data were analysed from end points >6 months duration, cross-over design, open-angle glaucoma or ocular hypertension and monotherapy. Multiple regression showed no significant association of WMD with trial duration (t(9) = 1.92, p = 0.09), trial design (t(9) = 1.79, p = 0.11), trial quality (t(9) = -0.46, p = 0.66), or monotherapy or adjunctive therapy (t(9) = -2.14, p = 0.06). Fatigue was less commonly associated with latanoprost (RR = 0.27, 95% CI 0.08 to 0.88). Publication bias was not evident on visual inspection of a funnel plot. CONCLUSION: Latanoprost is more effective than brimonidine as monotherapy in lowering IOP. Brimonidine is associated with a higher rate of fatigue.

Trypan blue identifies antimetabolite treatment area in trabeculectomy.

AIM: Colourless solutions of mitomycin C (MMC) and 5-fluorouracil (5-FU) are widely used during trabeculectomy to inhibit postoperative scarring. The poor visibility of these agents on the eye has several drawbacks including the inability to accurately assess the area of treatment. This study examined the utility of using trypan blue dye to colour antimetabolites used during trabeculectomy and the effect of trypan blue on antimetabolite cytotoxicity in vitro. METHODS: For in vitro experiments, MMC (0.4 mg/ml) and 5-FU (25 mg/ml) were reconstituted with or without trypan blue. A lactate dehydrogenase release assay was used to measure drug induced cell death and viable cell number 7 days after treatment. For clinical assessment, trypan blue 0.1% was added to MMC and 5-FU to final concentrations of between 0.01% and 0.05%. The mixture was applied to Tenon's capsule and sclera via pre-wet or into dry 5x8 mm sponges (MMC and 5-FU) for 3 minutes or by direct subconjunctival injection after completion of surgery (5-FU). Twenty two consecutive patients undergoing trabeculectomy either with or without trypan blue were followed for 2 years postoperatively. RESULTS: The addition of 0.05% trypan blue to MMC or 5-FU did not alter MMC induced cell death or the number of viable fibroblast in vitro. In vivo, trypan blue clearly delineated the antimetabolite treatment area and facilitated control of excess antimetabolite at the wound margins as well as sponge removal. With direct subconjunctival injection, total staining area varied for a given volume with location of the needle tip. Any leakage from the injection site could be easily seen. No adverse effects attributable to trypan blue were found in 2 years of follow up. CONCLUSIONS: Trypan blue permits delineation of antimetabolite/tissue interactions without affecting cytoxicity for the assays investigated. Trypan blue can be used to visualise antimetabolite soaked sponges, estimate treatment area, and show areas of unintended tissue contact during trabeculectomy. The addition of trypan blue to antimetabolites has potential benefits in clinical, research, and teaching aspects of ocular surgery and therapy.

Asymmetry in optic disc parameters: the Blue Mountains Eye Study.

PURPOSE: To examine asymmetry in vertical optic disc parameters among subjects classified as normal, as having ocular hypertension (OH), and as having open-angle glaucoma (OAG) in a population-based sample. METHODS: The Blue Mountains Eye Study examined 3654 people aged 49 to 97 years, including 2929 normal subjects, 118 with OH, and 79 with OAG in the groups of interest for the asymmetry study. Optic disc parameters were measured in a masked manner from stereo optic disc photographs. RESULTS: Vertical disc diameter asymmetry (the absolute value of left minus right disc diameters) was similar among normal, OH, and OAG groups (median, 0.07-0.08 mm). Vertical cup- disc ratio asymmetry was higher in patients with OAG (median, 0.11) than in normal subjects (median, 0.06; P < 0.0001) and in those with OH (median, 0.05; P < 0.0001) but was similar between normal subjects and patients with OH (P = 0.17). A cup- disc ratio asymmetry of 0.2 or more was found in 24% of patients with OAG, compared with 1% of patients with OH and 6% of normal subjects. Corresponding rates for cup- disc ratio asymmetry of 0.3 or more in these three groups were 10%, 0%, and 1%, respectively. Using multiple linear regression, cup-disc ratio asymmetry was associated with disc diameter asymmetry and intraocular pressure asymmetry. However, these two factors explained only 3% of the variability of cup- disc ratio asymmetry and 20% of cup diameter asymmetry. CONCLUSIONS: Despite differences between the OAG group and either the OH or normal groups, asymmetry alone was not useful in identifying patients with OAG. At all levels of asymmetry, subjects were more likely to be classified as normal than with OH or OAG.

Transplantation of adult living donor kidneys into infants and small children.

HYPOTHESIS: We hypothesized that improved outcomes following renal transplantation in high-risk infants and small children primarily are due to advances in immunosuppression and accurate diagnosis of rejection. Optimizing renal allograft perfusion is critical to achieving good early graft function and decreasing early graft loss. DESIGN: Twenty-eight consecutive recipients (weighing <20 kg) of adult living donor kidneys transplanted at our center from 1984 to 1999 were reviewed. Two groups were identified based on differing immunosuppression protocols and clinical surveillance. Actuarial graft and patient survival reported at 1, 3, and 5 years were compared for group 1 (1984-1991) and group 2 (1992-1999). Graft losses, categorized as immunologic or nonimmunologic, and the incidences of delayed graft function, vascular thrombosis, and rejection were compared. RESULTS: Graft and patient survival in group 1 (n = 13) at 1, 3, and 5 years was 77% and 92%, 54% and 85%, and 54% and 85%, respectively. In group 2, all 15 patients are alive with functioning grafts to date. Immunologic graft loss occurred in 5 of 13 patients in group 1 who developed chronic rejection. Nonimmunologic causes (vascular thrombosis [2 patients]) and patient death [1]) resulted in early graft failure within 2 weeks in 3 of 13 patients in group 1. The overall incidences of delayed graft function (10.7%) and thrombosis (7.1%) were low and did not differ between groups. Percutaneous renal biopsy was used more frequently in group 2 to evaluate graft dysfunction and guide treatment. CONCLUSIONS: We conclude that improved overall graft and patient survival in group 2 is owing to advances in immunosuppression and better treatment of rejection. Percutaneous renal biopsy allows prompt and accurate histological diagnosis of graft dysfunction. Surgical technique and aggressive fluid management aimed at maximizing renal allograft perfusion is critical in optimizing early graft function and decreasing vascular complications.

The effect of endotoxin on intestinal mucosal permeability to bacteria in vitro.

OBJECTIVE: To examine the role of the intestinal mucosa in bacterial translocation, in vitro bacterial passage across ileal mucosal segments mounted in Ussing chambers were studied in control and endotoxin (lipopolysaccharide)-treated rats. DESIGN: Experimental study. MATERIALS AND METHODS: Three groups of rats were studied. The experimental group received an intraperitoneal injection of lipopolysaccharide, while controls received an equivalent volume of saline solution; a third group received no treatment. Twenty-four hours later, all groups underwent laparotomy and organ culture to assess bacterial translocation. At the same time, a segment of mucosa from the terminal ileum of each animal was mounted in a Ussing chamber, and the transmucosal passage of labeled Escherichia coli from the luminal to serosal surface was assessed by results of serial cultures. RESULTS: In vivo bacterial translocation occurred in 100% of the lipopolysaccharide-treated animals, significantly higher than the incidence seen in controls (25%; P < .05). In vitro passage of labeled E coli across ileal mucosa in the Ussing chamber occurred in 78% of lipopolysaccharide-treated animals, while in controls transmucosal passage was seen in only 14% (P < .05). Histologic examination of mucosa from both groups using light and transmission electron microscopy demonstrated no structural differences between groups. CONCLUSIONS: Increased permeability to bacteria at the mucosal level contributes to the bacterial translocation seen in endotoxemia.

Delayed primary repair of esophageal atresia with tracheoesophageal fistula: is it worth the wait?

OBJECTIVE: To characterize a successful approach to the management of infants with long-gap esophageal atresia (EA) with tracheoesophageal fistula (TEF), significant prematurity with respiratory distress syndrome (RDS), or both, so as to preserve the native esophagus. DESIGN: A review of the medical records and office charts of a cohort of patients with EA and TEF. SETTING: A tertiary care children's hospital affiliated with a major university. PATIENTS: A total of 118 children with EA and TEF admitted from February 1986 through December 1996. All of the patients diagnosed as having EA and TEF during this period were included. INTERVENTION: Of the 118 infants, 88 received primary repair of EA and TEF within 48 hours of birth. An additional 23 children had the TEF divided and a gastrostomy placed secondary to (1) severe RDS and prematurity (n = 6), (2) long-gap EA (gap length > 4 cm or the upper pouch above the thoracic inlet (n = 10), or (3) associated cardiac defects (n = 7). Delayed primary EA repair was done when the RDS resolved or the gap length was 2 cm or less. MAIN OUTCOME MEASURES: Successful anastomosis of native esophagus. Comparison of incidence of gastroesophageal reflux, anastomotic complications, or survival between groups undergoing primary or delayed repair. RESULTS: Primary EA was accomplished in 88 patients. Delayed EA was successfully accomplished in 18 of the 19 surviving patients within 5 months, thereby preserving the native esophagus in all surviving infants. There was no difference in anastomotic complications, gastroesophageal reflux, or survival when the delayed group was compared with those who had a primary repair. CONCLUSIONS: Using delayed EA repair, all children with EA and TEF, regardless of gap length, can have their esophagus preserved. The primary cause of mortality was the association of a severe cardiac anomaly with EA and TEF.

Quantitative and morphologic analysis of bacterial translocation in neonates.

OBJECTIVE: To elucidate the mechanisms of bacterial translocation in animals fed a conventional formula by correlating transmucosal bacterial passage in vitro with the structural characteristics of the neonatal intestinal mucosa. DESIGN: Newborn rabbits were randomized to receive a conventional formula or breast milk. Bacterial translocation to the mesenteric lymph nodes, liver, and spleen was quantitated after 7 days, and transmucosal passage of bacteria was measured in vitro using the Ussing chamber. The mucosal membranes were examined by light, transmission electron, and confocal laser scanning microscopy. RESULTS: Bacterial passage was rarely seen in the breast milk-fed animals in contrast to the formula-fed animals. Unlike the normal-appearing membranes from breast milk-fed animals, the epithelial cells of formula-fed animals were vacuolated but healthy, with normal polarization and microvillus border by confocal laser scanning microscopy. Villi of formula-fed animals were less densely packed than those of the breast milk-fed animals. Bacterial adhesion, internalization, and transmucosal passage were seen only in membranes from formula-fed animals. Transmission electron microscopy demonstrated bacteria incorporating into the epithelial surface through an active phagocytic process, with rearrangement of the actin cytoskeleton. Once internalized, these bacteria were seen within the cytoplasmic vacuoles and subsequently in the submucosa. No bacteria passed between epithelial cells. CONCLUSION: Morphological changes in the intestinal mucosa of formula-fed newborn rabbits may increase permeability to bacteria.

Metabolic effects of neuropeptide Y injections into the paraventricular nucleus of the hypothalamus.

The metabolic effects of single injections of neuropeptide Y (NPY) into the paraventricular hypothalamus were investigated in an open-circuit calorimeter. Wistar rats were tested, with no food available during the tests. Over the dose range of 10-156 pmol NPY had large effects on respiratory quotient (RQ) while having no effect on energy expenditure or locomotor activity. The effects of NPY on RQ were unusual both in respect to their dose-response and time-dose-response characteristics. The lowest dose (10 pmol) produced a very low latency reduction in RQ which indicates a decreased utilization of carbohydrates as an energy substrate. The next higher dose (20 pmol) had no effect, whereas the next three doses (39, 78 and 156 pmol) produced increases in RQ which indicate an increased utilization of carbohydrates as an energy substrate. Surprisingly, the latencies of the increased RQs were dose-dependent over the range of 30 min to 20 h with the highest dose producing the longest latency effect. The finding of a positive relation of dose to response latency over a time range of from a few minutes to 20 h is unprecedented and appears to represent a neuromodulatory effect of NPY that acts in concert with its neurotransmitter effects. These data highlight the central role of NPY in modulating energy substrate utilization and indicate the importance of elucidating time-dose-response relationships when investigating the effects of NPY.

Optic disk size in open-angle glaucoma: the Blue Mountains Eye Study.

PURPOSE: To compare optic disk size in eyes of subjects classified as normal with the eyes of subjects with open-angle glaucoma, ocular hypertension, or pseudoexfoliation syndrome in an older population-based sample. METHODS: The Blue Mountains Eye Study examined 3,654 subjects. Vertical disk diameter was measured from stereoscopic disk photographs, and we used spherical equivalent refraction to correct for magnification. Analyses used all eyes in a general estimating equation model. RESULTS: Mean disk diameter was 1.556 mm in glaucomatous eyes, significantly different (P <.05) than normal eyes (1.506 mm) and eyes with ocular hypertension (1.494 mm) or pseudoexfoliation (1.501 mm). CONCLUSIONS: Patients with glaucoma have slightly larger optic disks than nonglaucomatous subjects.

Female reproductive factors and open angle glaucoma: the Blue Mountains Eye Study.

AIMS: To determine whether endogenous oestrogen exposures are associated with open angle glaucoma (OAG). METHODS: The Blue Mountains Eye Study examined 2072 women aged 49-97 years during 1992-4. Questions about female reproductive factors included age at menarche and menopause, parity, and use of hormone replacement therapy. Applanation tonometry, visual field tests, and stereo-optic disc photographs were performed. OAG was diagnosed when glaucomatous visual fields matched optic disc changes. Ocular hypertension (OH) was defined in the absence of glaucoma, but with intraocular pressure >or=22 mm Hg. RESULTS: A significantly increased OAG risk with later (>13 years) compared with earlier (or=50 years), adjusted OR = 1.7; CI: 0.7 to 3.8, and for shorter duration of endogenous oestrogen exposure (<30 years), adjusted OR = 1.8; CI: 0.6 to 5.3. Increasing parity was associated with an increased risk of OAG (p = 0.03) and decreased risk of OH (p = 0.03). CONCLUSION: The modest associations found in relation to late menarche and increased parity do not allow the exclusion of a possible role for endogenous female hormones in the pathogenesis of OAG.

The effect of optic disc diameter on vertical cup to disc ratio percentiles in a population based cohort: the Blue Mountains Eye Study.

OBJECTIVE: The 97.5th percentile for vertical cup to disc ratio (VCDR) has been proposed as a useful tool to assist in the diagnosis of glaucoma in population studies. Previous reports of VCDR percentiles have either not been adjusted for disc size or have been calculated by regression analysis from small hospital based cohorts. The authors' aim was to generate VCDR percentiles in a large, population based sample. METHODS: Data were collected from 3654 individuals, aged 49 years or older, living in the Blue Mountains, west of Sydney. Vertical disc diameter and VCDR were determined by planimetry from stereo optic disc photographs. The distribution of VCDR and percentiles (95th, 97.5th, 99th) were calculated. RESULTS: 6678 eyes were included in the analysis. Median cup to disc ratio, 95th, 97.5th, and 99th percentile increased with vertical optic disc diameter in a linear fashion. An increase of 0.2 in median VCDR (0.35 to 0.55) was observed between small (1.1-1.3 mm) and large (1.8-2.0 mm) optic discs. An equivalent increase of 0.2 (0.59 to 0.74) was observed for the 97.5th percentile from small to large discs. CONCLUSION: VCDR percentiles for a "normal" population, adjusted for vertical optic disc diameter are presented. One quarter of all discs fell within the small or large disc categories highlighting the importance for estimating optic disc size. These data may assist in the diagnosis of glaucoma in clinical practice as well as providing a normative database. Sole use of VCDR percentile cut offs in defining glaucoma cases in population surveys requires further validation.