Assessing professional competence in optometry - a review of the development and validity of the written component of the competency in optometry examination (COE).

BACKGROUND: Credentialing assessment for overseas-educated optometrists seeking registration in Australia and New Zealand is administered by the Optometry Council of Australia and New Zealand. The aim was to review the validation and outcomes of the written components of this exam to demonstrate credentialing meets entry-level competency standards. METHODS: The Competency in Optometry Examination consists of two written and two clinical parts. Part 1 of the written exam comprises multiple choice questions (MCQ) covering basic and clinical science, while Part 2 has 18 short answer questions (SAQ) examining diagnosis and management. Candidates must pass both written components to progress to the clinical exam. Validity was evaluated using Kane's framework for scoring (marking criteria, item analysis), generalization (blueprint), extrapolation (standard setting), and implications (outcome, including pass rates). A competency-based blueprint, the Optometry Australia Entry-level Competency Standards for Optometry 2014, guided question selection with the number of items weighted towards key competencies. A standard setting exercise, last conducted in 2017, was used to determine the minimum standard for both written exams. Item response theory (Rasch) was used to analyse exams, produce reliability metrics, apply consistent standards to the results, calibrate difficulty across exams, and score candidates. RESULTS: Data is reported on 12 administrations of the written examination since 2014. Of the 193 candidates who sat the exam over the study period, 133 (68.9%) passed and moved on to the practical component. Ninety-one (47.2%) passed both the MCQ and SAQ exams on their first attempt. The MCQ exam has displayed consistently high reliability (reliability index range 0.71 to 0.93, average 0.88) across all 12 administrations. Prior to September 2017 the SAQ had a set cutscore of 50%, and the difficulty of the exam was variable. Since the introduction of Rasch analysis to calibrate difficulty across exams, the reliability and power of the SAQ exam has been consistently high (separation index range 0.82 to 0.93, average 0.86). CONCLUSIONS: The findings from collective evidence support the validity of the written components (MCQ and SAQ) of the credentialing of the competency of overseas-educated optometrists in Australia and New Zealand.

Design of the low vision quality-of-life questionnaire (LVQOL) and measuring the outcome of low-vision rehabilitation.

PURPOSE: To design and validate a vision-specific quality-of-life assessment tool to be used in a clinical setting to evaluate low-vision rehabilitation strategy and management. METHODS: Previous vision-related questionnaires were assessed by low-vision rehabilitation professionals and patients for relevance and coverage. The 74 items selected were pretested to ensure correct interpretation. One hundred and fifty patients with low vision completed the chosen questions on four occasions to allow the selection of the most appropriate items. The vision-specific quality of life of patients with low vision was compared with that of 70 age-matched and gender-matched patients with normal vision and before and after low-vision rehabilitation in 278 patients. RESULTS: Items that were unreliable, internally inconsistent, redundant, or not relevant were excluded, resulting in the 25-item Low Vision Quality-of-Life Questionnaire (LVQOL). Completion of the LVQOL results in a summed score between 0 (a low quality of life) and 125 (a high quality of life). The LVQOL has a high internal consistency (alpha = 0.88) and good reliability (0.72). The average LVQOL score for a population with low vision (60.9 +/- 25.1) was significantly lower than the average score of those with normal vision (100.3 +/- 20.8). Rehabilitation improved the LVQOL score of those with low vision by an average of 6.8 +/- 15.6 (17%). CONCLUSIONS: The LVQOL was shown to be an internally consistent, reliable, and fast method for measuring the vision-specific quality of life of the visually impaired in a clinical setting. It is able to quantify the quality of life of those with low vision and is useful in determining the effects of low-vision rehabilitation.

Implementation methods for vision related quality of life questionnaires.

AIM: To determine the most reliable and consistent method and time interval over which to implement a vision impairment quality of life assessment tool. METHODS: 117 patients with low vision aged 9-101 years were assigned into three age, sex, and visual function matched groups (n = 39 in each) to answer the Low Vision Quality of Life (LVQOL) questionnaire by post, telephone, or in person. The LVQOL questionnaire was completed on four occasions, each separated by four weeks. RESULTS: Postal implementation was the most cost effective method, showed the highest internal consistency of LVQOL items, but resulted in a lower apparent quality of life score than either telephone or in-person interviews (p<0.001). There was no difference in test-retest reliability between the three methods of implementation (p = 0.12). The profile of LVQOL scores showed a trend towards reduced quality of life scores 3 months after the baseline measures, although this was not significant. CONCLUSION: Posting may be the method of choice for clinical measurement of vision related quality of life. Patients with greater visual impairment were no less likely to complete a questionnaire when implemented by post and there was no apparent bias from other people assisting them. The quality of life measure can occur at any time up to 2 months after low vision rehabilitation for the progressive nature of conditions causing low vision not to cause a decreased baseline score. The LVQOL was shown to be a highly internally consistent and reliable method for measuring quality of life in the visually impaired.

The practical near acuity chart (PNAC) and prediction of visual ability at near.

OBJECTIVE: To improve on present reading chart designs, providing a quick and accurate method to measure the near acuity threshold, of particular importance with low vision patients. DESIGN: The Practical Near Acuity Chart (PNAC) uses a single paragraph with 3 simple related words on each line (12 lower case letters). The line print size decreases in a logMAR progression (N80-N5). METHODS: The time taken to measure near acuity of 53 subjects aged 9-91 years with the PNAC and Bailey-Lovie near chart was recorded and compared to their distance acuity (Bailey-Lovie chart), contrast sensitivity (Melbourne Edge Test) and ability to read extracts of newsprint. RESULTS: There was no difference in near acuity threshold using related or un-related words. There was a high correlation (r = 0.97) between near acuity measured with the PNAC and Bailey-Lovie charts. However, the time taken to measure near acuity was significantly faster with the PNAC (32 +/- 2 s vs 76 +/- 4 s, p < 0.001). Near acuity measured with either chart was highly correlated (p < 0.001) to distance acuity (r = 0.74), contrast sensitivity (r = 0.62) and ability to read newsprint (r = 0.87). The PNAC was shown to have high test-reliable (r = 0.99). CONCLUSIONS: The PNAC offers a quick but accurate way to measure near acuity and shows a high degree of correlation with distance acuity, contrast sensitivity and the ability to read newsprint.

Contrast is enhanced by yellow lenses because of selective reduction of short-wavelength light.

PURPOSE: Although many studies have shown a subjective preference for yellow lenses, there has been little success in determining the clinical nature of this benefit. METHOD: Contrast sensitivity, color vision, accommodative-convergence, and visual acuity were measured in a group of 20 young subjects along with subjective rating of their perception through clear control lenses (380-nm cut-off), yellow lenses (450-nm cut-off), dark yellow lenses (511-nm cut-off), and orange lenses (527-nm cut-off). RESULTS: A systematic detriment to color vision was found to occur with increasing cut-off wavelength of the yellow lenses (p < 0.001) and this was significantly correlated to subjective ratings of color (r = -0.66) and brightness (r = -0.34). Perceived brightness significantly improved for the yellow (450-nm cut-off) lens only (p < 0.001). Although tinted lenses reduced contrast sensitivity to a white on black grating, there was a significant improvement in low to midrange spatial frequencies when measured using a white-on-blue grating. CONCLUSIONS: The detriment in color vision caused by yellow-colored lenses enhances contrast when viewing bright objects against a blue-based background, such as the sky. Contrast of overlying objects is enhanced is due to the selective reduction of short-wavelength light by the yellow lenses.

The changing face of the visually impaired: the Kooyong low vision clinic's past, present, and future.

PURPOSE: To demonstrate the changes that have occurred in a developed world low vision population over the past three decades and to examine the present rehabilitation of the visually impaired attending a multi-disciplinary low vision clinic. METHODS: A retrospective examination of the 22,860 patients attending the low vision clinic at Kooyong since its inauguration in 1972 to 1996 allowed the extraction of information on their age, gender, living status, and primary condition causing low vision. A prospective unified study of 590 patients attending the clinic over a 6-month period in 1998 examined the demographics of the present low vision population and what rehabilitation they received. RESULTS: The average age of patients attending the low vision clinic has steadily increased, with 87% over the age of 60 years in the mid-1990s compared to 71% in the mid-1970s. The percentage of female patients attending the clinic has also steadily risen over the past three decades (from 59 to 66%), as has the percentage of patients living alone (from 23 to 41%). The main change in the conditions causing visual impairment in the clinic's low vision population has been the increase in age-related macular degeneration (ARMD). The average presenting distance acuity was 6/38, improving to 6/30(-1) with refraction. One-third of the patients could manage N5 print with the aid of +4.00 near addition lenses or less. Over one-half were prescribed magnification aids, with 19% having need for 2 or more to accomplish their desired visual tasks. Two-thirds of the patients made use of staff from multiple disciplines during their visual rehabilitation. CONCLUSIONS: The low vision population has changed over the past three decades. Major changes that have implications on low vision rehabilitation services are the increasing age of the patients and the preponderance of ARMD.

Specific causes of death in miners and ex-miners of the Rhondda Fach 1950-80.

The specific causes of death for miners and ex-miners of the Rhondda Fach have been examined in detail using the data base provided by the 30 year follow up. The main findings are the lower specific mortality for those with category A, compared with those with categories 0, 1, 2, and 3, for all circulatory diseases (particularly ischaemic heart disease) and the raised mortality for gastric cancer. These results are surprising because a high proportion of those with, especially, categories 2 and 3 developed category A during the 30 years but fail to show the specific death rates typical of those with category A. Possible reasons for this are discussed and an explanation put forward.

Mortality of men in the Rhondda Fach 1950-80.

In a 30 year follow up study of 8526 men aged 20 and over in the Rhondda Fach 99.9% of the population was traced. Generally, the results are similar to those found in a 20 year follow up of the same subjects. Miners and ex-miners had an excess mortality compared with non-miners, but within the former only those who had had categories B and C pneumoconiosis showed a raised mortality. Category A pneumoconiosis was not associated with any excess compared with other miners and ex-miners. Two further aspects of the data relating to gastric cancer and progressive massive fibrosis will be examined in later reports.

The relevance in adults of air-flow obstruction, but not of mucus hypersecretion, to mortality from chronic lung disease. Results from 20 years of prospective observation.

From 1954 to 1961, pulmonary function was assessed in 2,718 British men by forced expiratory maneuvers, and mucus hypersecretion and smoking habits were assessed by questionnaires. In 20 to 25 yr of follow-up, 104 men (all of whom had smoked) died of chronic obstructive pulmonary disease (COPD). The risk of death from COPD was strongly correlated with the initial degree of air-flow obstruction. Among men with similar initial air-flow obstruction, however, age-specific COPD death rates were not significantly related to initial mucus hypersecretion, supporting the concept that air-flow obstruction and mucus hypersecretion are largely independent disease processes. A moderate relationship existed between initial mucus hypersecretion and subsequent lung cancer mortality, but it is not known whether this was due solely to a common correlation of both conditions with the effective degree of exposure of the large bronchi to causative factors such as tobacco smoke.

Are coalminers, with low "risk factors" for ischaemic heart disease at greater risk of developing progressive massive fibrosis?

Coalminers with "A" shadows (the first stage of progressive massive fibrosis (PMF)) have a similar standardised mortality ratio (SMR) to those without PMF, and those with A shadows have a much higher specific mortality from pneumoconiosis. It is therefore argued that either A shadows confer immunity against some other disease(s) or that those developing A shadows are selected on the basis of increased life expectancy. These two hypotheses were investigated and as the selection hypothesis appeared promising further studies were made to discover which specific cause of death might be associated with this selection. This, surprisingly, appeared to be ischaemic heart disease.