Refractive error magnitude and variability: Relation to age / Magnitud y variabilidad del error refractivo: relación con la edad

Purpose: To investigate mean ocular refraction (MOR) and astigmatism, over the human age range and compare severity of refractive error to earlier studies from clinical populations having large age ranges. Methods: For this descriptive study patient age, refractive error and history of surgery affecting refraction were abstracted from the Waterloo Eye Study database (WatES). Average MOR, standard deviation of MOR and astigmatism were assessed in relation to age. Refractive distributions for developmental age groups were determined. MOR standard deviation relative to average MOR was evaluated. Data from earlier clinically based studies with similar age ranges were compared to WatES. Results: Right eye refractive errors were available for 5933 patients with no history of surgery affecting refraction. Average MOR varied with age. Children < 1 yr of age were the most hyperopic (+1.79 D) and the highest magnitude of myopia was found at 27 yrs (-2.86 D). MOR distributions were leptokurtic, and negatively skewed. The mode varied with age group. MOR variability increased with increasing myopia. Average astigmatism increased gradually to age 60 after which it increased at a faster rate. By 85+ years it was 1.25 D. J0 power vector became increasingly negative with age. J45 power vector values remained close to zero but variability increased at approximately 70 years. In relation to comparable earlier studies, WatES data were most myopic. Conclusions: Mean ocular refraction and refractive error distribution vary with age. The highest magnitude of myopia is found in young adults. Similar to prevalence, the severity of myopia also appears to have increased since 1931

Objetivo: Estudiar la refracción ocular media (MOR) y el astigmatismo a lo largo del rango de la vida humana, y comparar la magnitud del error refractivo con estudios previos sobre poblaciones clínicas con rangos de edad amplios. Métodos: Para este estudio descriptivo, se extrajeron de la base de datos Waterloo Eye Study (WatES) la edad del paciente, el error refractivo y el historial de cirugía con repercusión en la refracción. Se evaluaron la MOR media, la desviación estándar de MOR y el astigmatismo con relación a la edad. Se calcularon las distribuciones refractivas para los grupos de edad evolutiva. Se evaluó la desviación estándar de MOR con respecto a MOR media. Se compararon los datos de los estudios clínicos previos con los rangos de edad similares de WatES. Resultados: Se dispuso de los errores refractivos del ojo derecho de 5.933 pacientes sin historial de cirugía con repercusión en la refracción. La MOR media sufrió variaciones con la edad. Los niños con edad <1 año reflejaron mayor hipermetropía (+1,79 D), encontrándose el mayor valor de miopía a los 27 años (-2,86 D). Las distribuciones de MOR fueron leptocúrticas, y negativamente sesgadas. La moda varió con el grupo de edad. La variabilidad de MOR se incrementó al aumentar la miopía. El astigmatismo medio aumentó gradualmente hasta los 60 años, pasados los cuales se incrementó a mayor velocidad. A los 85 años, o más, su valor fue de 1,25D. El vector de potencia J0 se modificó hacia valores más negativos con la edad. Los valores del vector de potencia J45 fueron cercanos a 0, aunque su variabilidad se incrementó a los 70 años, aproximadamente. Con relación a los estudios previos comparables, los datos WatES fueron más miópicos. Conclusiones: La refracción ocular media y la distribución del error refractivo varían con la edad. La mayor magnitud de la miopía se encontró en los adultos jóvenes. Al igual que la prevalencia, la gravedad de la miopía parece haberse incrementado desde 1931

Refractive error magnitude and variability: Relation to age.

PURPOSE: To investigate mean ocular refraction (MOR) and astigmatism, over the human age range and compare severity of refractive error to earlier studies from clinical populations having large age ranges. METHODS: For this descriptive study patient age, refractive error and history of surgery affecting refraction were abstracted from the Waterloo Eye Study database (WatES). Average MOR, standard deviation of MOR and astigmatism were assessed in relation to age. Refractive distributions for developmental age groups were determined. MOR standard deviation relative to average MOR was evaluated. Data from earlier clinically based studies with similar age ranges were compared to WatES. RESULTS: Right eye refractive errors were available for 5933 patients with no history of surgery affecting refraction. Average MOR varied with age. Children <1 yr of age were the most hyperopic (+1.79D) and the highest magnitude of myopia was found at 27yrs (-2.86D). MOR distributions were leptokurtic, and negatively skewed. The mode varied with age group. MOR variability increased with increasing myopia. Average astigmatism increased gradually to age 60 after which it increased at a faster rate. By 85+ years it was 1.25D. J0 power vector became increasingly negative with age. J45 power vector values remained close to zero but variability increased at approximately 70 years. In relation to comparable earlier studies, WatES data were most myopic. CONCLUSIONS: Mean ocular refraction and refractive error distribution vary with age. The highest magnitude of myopia is found in young adults. Similar to prevalence, the severity of myopia also appears to have increased since 1931.

Visual and binocular status in elementary school children with a reading problem / Estado visual y binocular en niños de primaria con dificultades lectoras

Purpose: This descriptive study provides a summary of the binocular anomalies seen in elementary school children identified with reading problems. Methods: A retrospective chart review of all children identified with reading problems and seen by the University of Waterloo, Optometry Clinic, from September 2012 to June 2013. Results: Files of 121 children (mean age 8.6 years, range 6-14 years) were reviewed. No significant refractive error was found in 81% of children. Five and 8 children were identified as strabismic at distance and near respectively. Phoria test revealed 90% and 65% of patients had normal distance and near phoria. Near point of convergencia (NPC) was < 5cm in 68% of children, and 77% had stereoacuity of ≤40seconds of arc. More than 50% of the children had normal fusional vergence ranges except for near positive fusional vergencce (base out) break (46%). Tests for accommodation showed 91% of children were normal for binocular facility, and approximately 70% of children had an expected accuracy of accommodation. Conclusion: Findings indicate that some children with an identified reading problem also present with abnormal binocular test results compared to published normal values. Further investigation should be performed to investigate the relationship between binocular vision function and reading performance

Objetivo: Este estudio descriptivo aporta un resumen de las anomalías binoculares observadas en niños de primaria en los que se identificaron problemas de lectura. Métodos: Revisión retrospectiva de las historias clínicas de todos los niños en los que se identificaron problemas de lectura, examinados en la Universidad de Waterloo, Clínica de Optometría, desde Septiembre de 2012 a Junio de 2013. Resultados: Se revisaron las historias de 121 niños (edad media 8,6 años, rango 6-14 años). No se encontró ningún error refractivo significativo en el 81% de los niños. Se identificaron cinco y ocho niños con estrabismo de visión lejana y cercana, respectivamente. La prueba de foria reveló que el 90% y 65% de los pacientes padecían foria en rango de normalidad para lejos y cerca. El punto próximo de convergencia (PPC) fue < 5cm en el 68% de los niños, y el 77% reflejó estereoagudeza ≤ 40 segundos de arco. Más del 50% de los niños tenía rangos de vergencia fusional normal, excepto para el punto de rotura de vergencia fusional positiva de cerca (46%). Las pruebas de acomodación reflejaron que el 91% de los niños tenía una flexibilidad binocular normal, y aproximadamente el 70% de los niños tenía una precisión de acomodación con arreglo a lo previsto. Conclusión: Los hallazgos indican que algunos niños con dificultades lectoras identificadas presentan también alteraciones en los resultados de las pruebas binoculares, en comparación a los valores normales publicados. Deberá investigarse más con respecto a la relación entre la función de la visión binocular y el rendimiento lector

Visual and binocular status in elementary school children with a reading problem.

PURPOSE: This descriptive study provides a summary of the binocular anomalies seen in elementary school children identified with reading problems. METHODS: A retrospective chart review of all children identified with reading problems and seen by the University of Waterloo, Optometry Clinic, from September 2012 to June 2013. RESULTS: Files of 121 children (mean age 8.6 years, range 6-14 years) were reviewed. No significant refractive error was found in 81% of children. Five and 8 children were identified as strabismic at distance and near respectively. Phoria test revealed 90% and 65% of patients had normal distance and near phoria. Near point of convergencia (NPC) was <5cm in 68% of children, and 77% had stereoacuity of ≤40seconds of arc. More than 50% of the children had normal fusional vergence ranges except for near positive fusional vergencce (base out) break (46%). Tests for accommodation showed 91% of children were normal for binocular facility, and approximately 70% of children had an expected accuracy of accommodation. CONCLUSION: Findings indicate that some children with an identified reading problem also present with abnormal binocular test results compared to published normal values. Further investigation should be performed to investigate the relationship between binocular vision function and reading performance.

Value of Routine Eye Examinations in Asymptomatic Patients.

PURPOSE: To determine if routine eye examinations in asymptomatic patients result in spectacle prescription change, new critical diagnosis, or new management of existing conditions. We also investigate whether age and time between assessments (assessment interval) impact detection rates. METHODS: The Waterloo Eye Study (WatES) database was created from a retrospective file review of 6397 patients seen at the University of Waterloo Optometry Clinic. Significant changes since the previous assessment (significant change) were defined as a change in spectacle prescription, presence of a new critical diagnosis, or a new management. Significant change, assessment interval, and age were extracted from the database for all asymptomatic patients presenting for a routine eye examination. The frequency of patients with significant change and the median assessment interval were determined for different age groups. RESULTS: Of 2656 asymptomatic patients, 1078 (41%) patients had spectacle prescription changes, 434 (16%) patients had new critical diagnoses, 809 (31%) patients had new managements, and 1535 (58%) patients had at least one of these (significant change). Median assessment intervals were 2.9 and 2.8 years for age groups 40 to <65 years and 20 to <40 years, respectively, approximately 1.5 years for patients 7 to <20, and between 1 and 1.5 years for patients <7 or >64. Controlling for assessment interval and sex, increasing age was associated with having a significant change (OR = 1.03, 95% CI 1.029-1.037). Similarly, controlling for age and sex, increased assessment interval was associated with having a significant change (OR = 1.06, 95% CI 1.02-1.11). CONCLUSIONS: In asymptomatic patients, comprehensive routine optometric eye examinations detect a significant number of new eye conditions and/or result in management changes. The number detected increases with age and assessment interval.

Evidence-based practice instruction by faculty members and librarians in North American optometry and ophthalmology programs.

North American optometry and ophthalmology faculty members and vision science librarians were surveyed online (14% response rate) about teaching evidence-based practice (EBP). Similar to studies of other health care programs, all five EBP steps (Ask, Acquire, Appraise, Apply, Assess) were taught to varying degrees. Optometry and ophthalmology EBP educators may want to place further emphasis on (1) the Apply and Assess steps, (2) faculty- and student-generated questions and self-assessment in clinical settings, (3) online teaching strategies, (4) programmatic integration of EBP learning objectives, and (5) collaboration between faculty members and librarians.

Increase in myopia prevalence in clinic-based populations across a century.

PURPOSE: The study's aim was to report prevalence estimates and age-related trends in refractive error in a clinic-based series and compare them to results from studies of a similar nature conducted since 1892. METHODS: Refractive error, patient age, and sex were collected from the files of all patients seen at the University of Waterloo School of Optometry and Vision Science clinic between January 2007 and January 2008. Patients were categorized as having myopia (<-0.5D mean ocular refraction [MOR]), hyperopia (>0.5D MOR), emmetropia, astigmatism (<-0.5D), and/or anisometropia (>1.0D difference between eyes). The prevalence of all refractive components was determined overall and in 1- and 5-year age groups, and then compared to data from older clinic-based studies. Refractive trends over time were noted. The prevalence of myopia and hyperopia were compared to older studies. RESULTS: The lowest prevalence of myopia was 5% at 0 to 5 years of age, after which it increased to 72% at 20 to 30 years of age and then decreased to 22% in patients older than 70 years. A myopic peak occurred at 24 years of age. The prevalence of hyperopia followed opposite trends with a minimum prevalence of 6% at 25 to 30 years of age. Peaks in emmetropia prevalence were 55% at 5 to 10 years of age and 37% at 45 to 50 years of age. The prevalence of astigmatism and anisometropia increased with age. The Waterloo Eye Study showed a higher prevalence of myopia across all ages compared to the older studies with a peak prevalence of 72% compared to 21% in the oldest (Herrnheiser) study from 1892. CONCLUSIONS: In the last 100 years, there appears to have been a myopic shift in clinic-based populations and myopia prevalence appears to follow a predictable pattern with age.

Eye examinations improve visual acuity across ages.

OBJECTIVE: To investigate changes in distance best corrected visual acuity (BCVA) relative to presenting visual acuity (PVA) as a function of age and the number of years between eye examinations. DESIGN: Retrospective cross-sectional study. PARTICIPANTS: 6397 patient files at a large Canadian Optometric Clinic. METHODS: A retrospective file review of patients aged 4 to 93 years from the University of Waterloo, Optometry Clinic was conducted. Mean decimal PVA values were calculated for all patients grouped by year of age, and a function was fit to these data using nonlinear regression. The same was done for BCVA and the functions were compared. In addition, the mean logMAR difference between PVA and BCVA was determined for patients grouped by the length of time between the study visual assessment and their previous visual assessment independent of patient age. RESULTS: Right and left eye functions were not significantly different from each other for either PVA or BCVA. BCVA functions were significantly greater than PVA functions for both right (F[3174] = 194.7, p < 0.0001) and left (F[3174] = 206.0, p < 0.0001) eyes. PVA differed (≥1 line) from BCVA in at least 1 eye in 70% (n = 4054) of patients. The difference between BCVA and PVA increased as the length of time between assessments increased from 0.075 logMAR for <1 year to 0.107 logMAR for ≥5 years. CONCLUSIONS: Refractive testing resulted in an improvement in BCVA over PVA in the majority of patients, over a wide range of ages.

Binocular vision and eye movement disorders in older adults.

PURPOSE: To determine the prevalence of binocular vision (BV) and eye movement disorders in a clinic population of older adults. METHODS: Retrospective clinic data were abstracted from files of 500 older patients seen at the University of Waterloo Optometry Clinic over a 1-year period. Stratified sampling gave equal numbers of patients in the 60 to 69, 70 to 79, and 80+ age groups. Data included age, general and ocular history and symptoms, use of antidepressants, a habit of smoking, refraction, visual acuity, BV and eye movement status for the most recent full oculo-visual assessment, and an assessment 10 years prior. The prevalence of any BV or eye movement abnormal test (AT) result, defined as a test result outside the normal range, was determined. This included strabismus (any) or phoria; incomitancy; poor pursuits; and remote near point of convergence (NPC). The prevalence of significant BV disorders (diagnostic entities, i.e., a clinical condition that may need treatment and may have functional implications) was also determined. RESULTS: The prevalence of any BV or eye movement at was 41%, 44%, and 51% in the 60 to 69, 70 to 79, and 80+ age groups, respectively. These figures were lower for 10 years earlier: 31%, 36%, and 40% for ages 50 to 59, 60 to 69, and 70+, respectively. The prevalence of any BV or eye movement disorder was 27%, 30%, and 38% for the three age groups and 17%, 19%, and 24% for 10 years prior. Age and use of antidepressants most commonly predicted BV or eye movement AT or disorder. CONCLUSIONS: BV disorders are common among older adults.

Age-related cataract is associated with type 2 diabetes and statin use.

PURPOSE: Diabetes has been shown to be a risk factor for age-related (AR) cataract. As statins (HMG-CoA reductase inhibitors) are now commonly prescribed for patients with type 2 diabetes, their impact on AR cataract prevalence should be considered. This study determines associations between AR cataract, type 2 diabetes, and reported statin use in a large optometric clinic population. METHODS: In all, 6397 patient files (ages <1-93 years) were reviewed. Overall prevalence of statin use was calculated for patients with type 2 diabetes (n = 452) and without diabetes (n = 5884). Multivariable logistic regression analysis for AR cataract was performed controlling for patient sex, smoking, high blood pressure, type 2 diabetes, and statin use. RESULTS: The prevalence of statin use (in patients aged >38 years) was 56% for those with type 2 diabetes and 16% for those without diabetes. Type 2 diabetes was significantly associated with nuclear sclerosis (OR = 1.62, 1.14-2.29) and cortical cataract (OR = 1.37, 1.02-1.83). Statin use was associated with nuclear sclerosis (OR = 1.48, 1.09-2.00) and posterior subcapsular cataract (OR = 1.48, 1.07-2.04). The 50% probability of cataract in statin users occurred at age 51.7 and 54.9 years in patients with type 2 diabetes and without diabetes, respectively. In non-statin users, it was significantly later at age 55.1 and 57.3 years for patients with type 2 diabetes and without diabetes, respectively (p < 0.001). CONCLUSIONS: In this population, statin use was substantially higher in patients with type 2 diabetes and was associated with AR cataracts. Further long-term study is warranted to recommend monitoring of crystalline lenses in patients with type 2 diabetes benefiting from statins.

Evaluation of the clinical maxim: "If it ain't broke, don't fix it".

PURPOSE: A significant number of patients return to optometric practice dissatisfied with their spectacles. An important question is whether any of these cases are preventable. There are several different clinical maxims that are used to modify the subjective refraction when determining the refractive prescription. These maxims aim to improve patient comfort and adaptation and thereby reduce patient dissatisfaction with new spectacles. They are not based on research evidence, but rather on expert opinion gained from clinical experience. The aim of this study was to retrospectively analyze a large number of case records of dissatisfied patients to assess the possible usefulness of the prescribing maxim "if it ain't broke, don't fix it." METHODS: Three hundred eighteen non-tolerance cases from a university-based Canadian optometric clinic were categorized by a focus group of optometrists. Three prescribing categories were defined and comprised cases in which application of the proposed maxim may have prevented the recheck eye examination; a more limited application of the maxim for one working distance may have been appropriate; and finally scenarios in which the maxim did not work in that the practitioner was judged to have initially followed the maxim, yet patient dissatisfaction was still reported. The remaining unallocated records comprised prescribing situations outside the scope of this study. RESULTS: Approximately 32% of non-tolerance cases were judged to have been preventable by use of the proposed maxim. Furthermore, an additional 10% reduction in recheck cases may have been possible by a more liberal interpretation of the maxim. Conversely, 4% of cases were deemed to comprise scenarios in which the maxim was followed yet the patient returned later to report problems with their spectacles. CONCLUSIONS: The prescribing maxim "if it ain't broke, don't fix it" appears to have a role in reducing recheck eye examinations and improving patient satisfaction with new spectacles.

Modifications made to the refractive result when prescribing spectacles.

PURPOSE: The purpose of this study was to determine how optometric practitioners modify the subjective refractive result when prescribing spectacles. METHODS: Refractive data were gathered for patient visits at the School of Optometry, University of Waterloo, between January 2007 and January 2008. The entering prescription, subjective refraction, and exiting prescription were analyzed from 5001 records for patients aged ≥ 7 years. RESULTS: The refraction was modified to create the prescription in at least one eye in 45% of cases; specifically, 27% of cases for the sphere power, 18% for the cylinder power, 25% for the cylinder axis, and 21% for the add. Significant differences, defined as ≥ 0.50 D in sphere, cylinder, or add power or a change in axis of 15° for cylinders < 1 D, 10° for cylinders between 1 and ≤ 2, and 5° for cylinders >2, were made in at least one eye in 17% of cases; specifically 9% of cases for the sphere power, 6% for the cylinder power, 6% for the cylinder axis, and 5% for the add. Spheres were more likely to be modified in the minus direction (weaker plus and stronger minus power) (18 vs. 11%), cylinder powers reduced (14 vs. 5%), and adds increased in power (12 vs. 8%). Modifications to create the exiting prescription were made to be closer or the same as the entering prescription 97% of the time. However, modifications were such that the entering prescription was duplicated exactly only 0.7% of the time. CONCLUSIONS: Optometric practitioners routinely modify the subjective refraction to create the prescription. Small modifications are common, whereas larger modifications are used more sparingly. Because there is a significant amount of clinical judgment involved in determining the refractive prescription, reliance on automated or subjective refraction alone would not be prudent.

Modeling the prevalence of age-related cataract: Waterloo eye study.

PURPOSE: To report on the prevalence of age-related (AR) cataract in an optometric clinic population including male and female subgroups. METHODS: Retrospective patient file data reviewed for the Waterloo Eye Study database included age, sex, date of lens extraction (LE), and presence of AR cataract [nuclear sclerosis (NS), cortical cataracts (CC), posterior subcapsular (PSC) or associated LE]. Prevalence (%) was calculated for overall AR cataract, NS, CC, PSC, and bilateral LE for all Waterloo Eye Study patients. Logistic regression analysis was used to create age functions for overall AR prevalence and for significant differences in cataract types for males and females. The distribution of homogeneous and mixed cataract and mean age of first LE were determined for males and females. RESULTS: The prevalence of all AR, NS, CC, PSC, and bilateral LE was 35.3, 28.8, 9.9, 3.6, and 14.0%, respectively. Being female was associated with an increased prevalence of CC (odds ratio = 1.54, 95% confidence interval, 1.27 to 1.88) and bilateral LE (odds ratio = 1.41, 95% confidence interval, 1.09 to 1.84). Females reached 50% prevalence earlier than men for CC (76.7 vs. 82.6 years, p 0.05) and bilateral LE (84.6 vs. 90.5 years, p 0.05). Males had an earlier age of first LE than females (70.4 vs. 73.2 years; p 0.01). CONCLUSIONS: Logistic regression modeling indicates that being female in this optometric clinic population was associated with an increased prevalence of CC, mixed cataract, surgical intervention, and later age of first LE. These data are important for public health planning.

Prescribing for hyperopia in childhood and teenage by academic optometrists.

PURPOSE: The purpose of this study was to examine the prescribing patterns of academic optometrists for infants, children, and teenagers with hyperopia and the factors that affected the decision to prescribe. A comparison was made to published guidelines for prescribing for hyperopia in children. METHODS: The Waterloo Eye Study (WatES) database is a database of all patients attending the Primary Care Clinic or the Pediatric Clinic at the School of Optometry, University of Waterloo, between February 2007 and January 2008. Records for 698 patients aged from birth to 19 years with hyperopia but without strabismus or significant anisometropia were extracted. They were analyzed to determine the factors that predicted whether a child was prescribed spectacles and the 50% prescribing points for hyperopia and astigmatism according to age. RESULTS: Univariate analysis showed that the level of hyperopia, astigmatism, age, distance, and near phoria and presence of symptoms were associated with the prescription of spectacles (p < 0.05). Multivariate analysis showed that the prescription of spectacles was predicted by age, highest sphere (either right or left eye), highest cylinder, the presence of symptoms, and distance phoria. Among 0 to 3 year olds, all the children with 5 D or more of hyperopia had been prescribed spectacles. Among the 4 to 6 year olds, this point was 3.25 D; and for the 7 to 19 year olds, it was 2.25 D. The levels at which 50% of the population had been prescribed spectacles was 3.7, 1.8, and 1.1 D for the 0 to 3 year olds, 4 to 6 year olds, and 7 to 19 year olds, respectively. There was frequently a difference between the refraction and the prescription such that the younger children, in particular, were often under corrected for both hyperopia and astigmatism. CONCLUSIONS: The optometrists in this academic setting appear to follow the available optometric guidelines for prescribing for hyperopia. They tend to prescribe for lower levels of hyperopia than U.S. ophthalmologists.

Waterloo Eye Study: data abstraction and population representation.

PURPOSE: To determine data quality in the Waterloo Eye Study (WatES) and compare the WatES age/sex distribution to the general population. METHODS: Six thousand three hundred ninety-seven clinic files were reviewed at the University of Waterloo, School of Optometry. Abstracted information included patient age, sex, presenting chief complaint, entering spectacle prescription, refraction, binocular vision, and disease data. Mean age and age distributions were determined for the entire study group and both sexes. These results were compared with Statistics Canada (2006) estimates and information on Canadian optometric practices. Inter- and intraabstractor reliability was determined through double entry of 425 and 50 files, respectively; the Cohen kappa statistic (K) was calculated for qualitative data and the intraclass correlation coefficient (ICC) for quantitative data. Availability of data within the files was determined through missing data rates. RESULTS: The age of the patients in the WatES ranged from 0.2 to 93.9 years (mean age, 42.5 years), with all age groups younger than 85 years well represented. Females comprised 54.1% and males 45.9% of the study group. There were more older patients (>65 years) and younger patients (<10 years) than in the population at large. K values were highest for demographic information (e.g., sex, 0.96) and averaged slightly less for most clinical data requiring some abstractor interpretation (0.71 to 1.00). The two lowest interabstractor values, migraine (0.41) and smoking (0.26), had low reporting frequencies and definition ambiguity between abstractors. Intraclass correlation coefficient values were >0.90 for all but one continuous data type. Missing data rates were <2% for all but near phoria, which was 7.4%. CONCLUSIONS: The WatES database includes patients from all age groups and both sexes. It provides a fair representation of optometric patients in Canada. Its large sample size, good interabstractor repeatability, and low missing data rates demonstrates sufficient data quality for future analysis.

Comparison of alternate cover test reliability at near in non-strabismus between experienced and novice examiners.

PURPOSE: The purpose of this study was to determine the reliability of the prism neutralized alternate cover test (ACT) used to measure near phoria in non-strabismic participants as measured by experienced and novice examiners and to compare the values to results obtained by eye tracking. METHODS: Two experienced optometrists and two optometry students performed the ACT at 40 cm on 50 non-strabismic participants. The ACT was then repeated with the subjects wearing an eye tracker. The saccade amplitude of the eye movement recordings was used to determine the phoria. The reliability was determined using Bland-Altman analysis to determine the mean of the differences in the groups and the 95% limits of agreement. RESULTS: The phoria range determined by the eye tracker was between 6 pd eso and 19 pd exo. The mean of the difference in values and 95% limits of agreement between the experienced examiners was 0.7 +/- 3.0 pd; between the novice examiners was -0.1 +/- 4.4 pd; between the experienced and novice examiners was 0.8 +/- 3.5 pd; between the eye tracker and the experienced examiners was 0.6 +/- 3.5 pd; between the eye tracker and novice examiners was 1.4 +/- 3.6 pd. CONCLUSIONS: The mean differences of the ACT result between experienced examiners, novice examiners, and the eye tracker, were not clinically meaningful. However, the 95% limits of agreement were quite high (+/-3.0-4.4 pd). This information is useful for clinical decision making, student education and student evaluation.

What healthcare students do with what they don't know: the socializing power of 'uncertainty' in the case presentation.

Healthcare students learn to manage clinical uncertainty amid the tensions that emerge between clinical omniscience and the 'truth for now' realities of the knowledge explosion in healthcare. The case presentation provides a portal to viewing the practitioner's ability to manage uncertainty. We examined the communicative features of uncertainty in 31 novice optometry case presentations and considered how these features contributed to the development of professional identity in optometry students. We also reflected on how these features compared with our earlier study of medical students' case presentations. Optometry students, like their counterparts in medicine, displayed a novice rhetoric of uncertainty that focused on personal deficits in knowledge. While optometry and medical students shared aspects of this rhetoric (seeking guidance and deflecting criticism), optometry students displayed instances of owning limits while medical students displayed instances of proving competence. We found that the nature of this novice rhetoric was shaped by professional identity (a tendency to assume an attitude of moral authority or defer to a higher authority) and the clinical setting (inpatient versus outpatient settings). More explicit discussions regarding uncertainty may help the novice unlock the code of contextual forces that cue the savvy member of the community to sanctioned discursive strategies.

Tensions in the field: teaching standards of practice in optometry case presentations.

PURPOSE: Professional identity formation and its relationship to case presentations were studied in an optometry school's onsite clinic. METHODS: Eight optometry students and six faculty optometrists were audio-recorded during 31 oral case presentations and the teaching exchanges related to them. Using convenience sampling, interviews were audio-recorded of four of the students and four of the optometrists from the field observations. After transcribing these audio-recordings, the research team members applied a grounded theory method to identify, test, and revise emergent themes. The theme reported herein pertains to communicating standards of practice. RESULTS: Faculty optometrists demonstrated three ways of communicating standards of practice to optometry students during case presentations: Official Way, Our Way, and My Way. Although there were differences between these standards, the rationale for the disparities was rarely explicitly articulated by the instructors to the students. Without this information, the incongruity among the standards was left to the students to interpret on their own. CONCLUSIONS: The risk created by faculty not articulating the rationale underlying standards of practice was that students misinterpreted the optometrists' ways as idiosyncratic. Thus, opportunities were missed in the educational setting to assist students in making responsible decisions, locating their position in practice, and shaping their professional identity. Competing responsibilities of patient care and student education left instructors with little time to articulate rationale for standards of practice. Therefore, educators must reflect on innovative ways to bring into relief the logic behind their actions when working with novices.