Compliance with methodological standards when evaluating ophthalmic diagnostic tests.
(9/577)
PURPOSE: To draw attention to the importance of methodological standards when carrying out evaluations of ophthalmic diagnostic tests by reviewing the extent of compliance with these standards in reports of evaluations published within the ophthalmic literature. METHODS: Twenty published evaluations of ophthalmic screening/diagnostic tests or technologies were independently assessed by two reviewers for compliance with the following methodological standards: specification of the spectrum composition for populations used in the evaluation, analysis of pertinent subgroups, avoidance of work-up (verification) bias, avoidance of review bias, presentation of precision of results for test accuracy, presentation of indeterminate test results, and presentation of test reproducibility. RESULTS: Compliance ranged from just 10% (95%CI, 1%-32%) for presentation of test reproducibility data and avoidance of review bias to 70% (95%CI, 46%-88%) for avoidance of work-up bias and presentation of indeterminate test results. Only 5 of the 20 evaluations complied with four or more of the methodological standards and none with more than five of the standards. CONCLUSIONS: The evaluations of ophthalmic diagnostic tests discussed in this article show limited compliance with accepted methodological standards but are no worse than previously described for evaluations published in general medical journals. Adherence to these standards by researchers can improve the study design and reporting of evaluations of new diagnostic techniques. Limited compliance, combined with a lack of awareness of the standards among users of research evidence, may lead to the inappropriate adoption of new diagnostic technologies, with a consequent waste of health care resources. (+info)
Screening for refractive errors in children: accuracy of the hand held refractor Retinomax to screen for astigmatism.
(10/577)
AIMS: To assess the reliability of the hand held automated refractor Retinomax in measuring astigmatism in non-cycloplegic conditions. To assess the accuracy of Retinomax in diagnosing abnormal astigmatism in non-cycloplegic refractive screening of children between 9 and 36 months. METHODS: Among 1205 children undergoing a non-cycloplegic refractive screening with Retinomax, 299 (25%) had repeated non-cycloplegic measurements, 302 (25%) were refracted under cycloplegia using the same refractor, and 88 (7%) using retinoscopy or an automated on table refractor. The reproducibility of non-cycloplegic cylinder measurement was assessed by comparing the cylindrical power and axis values in the 299 repeated measurements without cycloplegia. The influence of the quick mode on cylinder measurement was analysed by comparing the cylinder and axis value in 93 repeated measurements without cycloplegia where normal mode was used in one measurement and quick mode in the other. Predictive values of the refractive screening were calculated for three different thresholds of manifest astigmatism (> or = 1.5, > or = 1.75, and > or = 2 D) considering as a true positive case an astigmatism > or = 2 D under cycloplegic condition (measured by retinoscopy, on table, or hand held refractor). RESULTS: The 95% limits of agreement between two repeated manifest cylinder measurements with Retinomax attained levels slightly less than plus or minus 1 D. The 95% limits of agreement for the axis were plus or minus 46 degrees. The comparison of non-cycloplegic measurements in the quick and normal mode showed no significant difference and 95% limits of agreement plus or minus 0.75 D. The mean difference between non-cycloplegic and cycloplegic cylinder values measured by Retinomax reached 0.17 D and was statistically significant. Manifest thresholds of > or = 1.5 D, > or = 1.75 D, > or = 2 D cylinder value diagnosed 2 D of astigmatism under cyclplegia respectively with 71-84%, 59-80%, 51-54% of sensitivity (right eye-left eye) and 90-92%, 95%, 98% of specificity. CONCLUSION: Without cycloplegia, Retinomax is able to measure cylinder power with the same reproducibility as cycloplegic retinoscopy. No significant difference was found in the cylinder values obtained with the quick and the normal modes. Therefore, the quick mode of measurement is recommended as it is more feasible in children. No difference, which is significant from a screening point of view, exists between the non-cycloplegic and the cycloplegic cylinder value (< 0.25 D). Retinomax diagnoses abnormal astigmatism (> or = 2 D) in a non-cycloplegic refractive screening at preschool ages with 51-84% sensitivity rates and 98-90% specificity rates, depending on the chosen threshold of manifest astigmatism. If 2 D of manifest astigmatism is chosen as a positive test, the positive predictive value of the screening reaches 81-84% and the negative predictive value 91-90% (right eye-left eye). (+info)
Endoscopy of the lacrimal system.
(11/577)
BACKGROUND/AIM: Until recently, diagnosis of disorders of the lacrimal system has depended on digital dacryocystography and on clinical examinations such as the fluorescein dye test, lacrimal probing, and irrigation. The lacrimal system and its mucous membranes can now be viewed directly with a lacrimal endoscope. While the first endoscopes were rigid and limited by poor picture quality in axial illuminations, the new generation of endoscopes are a great leap forward for new diagnostic and therapeutic approaches. METHODS: 132 patients ranging in age from 8 months to 73 years with nasolacrimal obstruction were referred to the lacrimal department. Diagnostic lacrimal imaging utilising various small calibre endoscopes less than 0.5 mm in external diameter was performed. The endoscopes are coupled to specially designed lacrimal probes as well as a CCD camera and a video recorder. The imaging was performed during standard lacrimal probing and irrigation in an outpatient clinic setting in 120 of 132 patients RESULTS: All patients reported the pain of endoscopy as being similar to that of standard lacrimal probing and irrigation. No adverse effects such as bleeding or lacrimal perforation were noted. Endoscopic manipulation was not too difficult and the picture quality, depth of focus, and illumination were satisfactory in all cases. The most common site of stenosis was the nasolacrimal duct (59 patients), followed by the lacrimal sac (39 patients) and the canaliculi (34 patients). In 25 patients, partial obstruction, rather than complete stenosis, was visualised as a narrow lumen, which widened during irrigation. In 14 of 28 patients, obstruction was due to canalicular submucosal folds and was removed with laser. In addition, the colour and consistency of the lining mucosa correlated with type of obstruction. Normal mucosa is smooth and light pink in colour. Inflammatory changes manifest as thickened and reddish grey mucosa. More complete stenosis is shown as fibrotic plaques with grey white inelastic membranes. CONCLUSION: Lacrimal endoscopy is a new, non-invasive method used to view directly and localise obstructions precisely. It allows differentiation between inflammatory, partial, and complete stenosis. Endoscopy enables one to choose the appropriate surgical therapy for patients. Patients tolerated the procedure well without any adverse reactions or effects. While it may not replace standard probing and irrigation, this technique is an extremely useful adjunct in determining the proper surgical modality, ease, and tolerance of the endoscopic manipulation by patients, and obtaining sharp and clear images of the nasolacrimal outflow system anatomy and pathology. Differentiation of various types of obstruction by precise location and severity can be achieved. (+info)
Non-communication between ophthalmologists and optometrists.
(12/577)
Many patients seen in the British hospital eye service are referred by high-street optometrists; and, if the optometrist is to receive feedback from the ophthalmologist, the patient should consent to disclosure of medical information. On the referral form (revised GOS 18) there is a space for this purpose. We investigated the level of communication by asking optometrists in our hospital catchment area about their use of the GOS 18 form and by examining the medical records of all new patients seen in the eye outpatient department in one month. 79 optometrists (55%) returned the questionnaire. 54 routinely used the GOS 18; and, of these, 10 said they obtained patient consent always, 23 sometimes and 21 never. 158 of 555 sets of medical notes contained an optometrist's referral, 107 of them on the revised GOS 18; and patient consent had been recorded on 17 of these forms. Ophthalmologists responded to the optometrist in 2/17 (12%) cases where consent had been obtained and 15/90 (17%) where it had not. Ophthalmologists could provide much better feedback to optometrists. The GOS 18 form could be used more effectively; and there is no reason why patient consent to disclosure of medical information should not be obtained by ophthalmologists as well as by optometrists. (+info)
Ophthalmology's future in the next decade: a historical and comparative perspective.
(13/577)
PURPOSE: To gain a historical and comparative perspective about the future of ophthalmology within the profession of medicine. METHODS: A literature search is made of disciplines other than medicine (history, sociology, philosophy, economics, and ethics) in order to assess factors responsible for survival and healthiness of a profession. The "learned" professions (medicine, law, and theology) are assessed. Other "professional" careers valued by society (sports and classical music) are reviewed. RESULTS: From the perspective of other disciplines, the future of ophthalmology is seen as vulnerable and fragile. Survival of professions, be they classically or economically defined, is linked to societal needs, a profession's unique commitment and ability to provide services to society, and the profession's maintenance of knowledge as well as skill-based services. Historical evidence has shown erosion of a profession's power consequent to capitalist influences, government influences, access of skills by less trained individuals, and elitist posturing by a profession. Comparative evidence has shown societal acceptance of an escalation of salaries for designated superstars, increasing roles and influence of managerial personnel, and trivialization of values other than economic ones. CONCLUSION: Attention to historical and comparative trends by individual ophthalmologists as well as associations representing ophthalmologists is mandatory if ophthalmology as we know it is to survive within the profession of medicine. (+info)
A value analysis model applied to the management of amblyopia.
(14/577)
PURPOSE: To assess the value of amblyopia-related services by utilizing a health value model (HVM). Cost and quality criteria are evaluated in accordance with the interests of patients, physicians, and purchasers. METHODS: We applied an HVM to a hypothetical statistical ("median") child with amblyopia whose visual acuity is 20/80 and to a group of children with amblyopia who are managed by our practice. We applied the model to calculate the value of these services by evaluating the responses of patients and physicians and relating these responses to clinical outcomes. RESULTS: The consensus value of care for the hypothetical median child was calculated to be 0.406 (of 1.000). For those children managed in our practice, the calculated value is 0.682. Clinically, 79% achieved 20/40 or better visual acuity, and the mean final visual acuity was 0.2 logMAR (20/32). Value appraisals revealed significant concerns about the financial aspects of amblyopia-related services, particularly among physicians. Patients rated services more positively than did physicians. CONCLUSIONS: Amblyopia care is difficult, sustained, and important work that requires substantial sensitivity to and support of children and families. Compliance and early detection are essential to success. The value of amblyopia services is rated significantly higher by patients than by physicians. Relative to the measured value, amblyopia care is undercompensated. The HVM is useful to appraise clinical service delivery and its variation. The costs of failure and the benefits of success are high; high-value amblyopia care yields substantial dividends and should be commensurately compensated in the marketplace. (+info)
Evidence-based medicine regarding the prevention of retinal detachment.
(15/577)
PURPOSE: To assess the quality of information in the literature regarding the prevention of retinal detachment in an effort to establish appropriate practice guidelines. METHODS: A panel of vitreoretinal experts performed a literature review of all publications in the English language for articles about prevention of retinal detachment. These article were then used to prepare recommendations for patient care in an American Academy of Ophthalmology "Preferred Practice Pattern" (PPP). Each recommendation was rated according to its importance in the care process and the strength of evidence supporting the given recommendation. RESULTS: Most recommendations were given a rating of "A" (most important to patient care). Only a single publication was graded as Level I (providing strong evidence in support of a recommendation), and this was not a prospective trial. Of the few publications rated as Level II (substantial evidence), most were studies documenting a lack of treatment benefit. Because of an absence of Level I and Level II studies in the literature, Level III (consensus of expert opinion) was the basis for most recommendations in the PPP. CONCLUSION: The current literature regarding prevention of retinal detachment does not provide sufficient information to strongly support prophylactic treatment of lesions other than symptomatic flap tears. Prospective randomized trials of prophylactic therapy are indicated. Eyes highly predisposed to retinal detachment should be considered for such studies. (+info)
A new digital optic disc stereo camera: intraobserver and interobserver repeatability of optic disc measurements.
(16/577)
AIMS: To investigate the intraobserver and interobserver repeatability of optic disc measurement using a new digital optic disc stereo camera. METHODS: 112 consecutive new patients presenting to a glaucoma service had dilated optic disc photography performed using a new digital stereo camera (Discam, Marcher Enterprises Ltd, Hereford). The images were analysed by two masked observers using a stereo viewer and computer simulated stereopsis. Vertical and horizontal cup:disc ratios (CDR), cup area:disc area, and cup circumference:disc circumference were computed. Intraobserver and interobserver repeatability analyses were performed. Intraclass correlation coefficients (ICC) and 95% tolerance for change (TC) were computed. RESULTS: 220 optic discs were photographed, of which 196 were suitable for analysis (10 were of poor image quality and 14 had anomalous discs). Mean age of patients was 65 years, 60 were male and 48 female. For intraobserver measurements of: horizontal CDR, ICC = 0.94, TC = 0.11 (15% of range); vertical CDR, ICC = 0.92, TC = 0.14 (16% of range); cup area:disc area, ICC = 0.95, TC = 0.10 (13% of range), and cup circumference:disc circumference, ICC = 0.95, TC = 0.09 (14% of range). For interobserver measurements of: horizontal CDR, ICC = 0.89, TC = 0.14 (19% of range); vertical CDR, ICC = 0.90, TC = 0.14 (16% of range); cup area:disc area, ICC = 0.92, TC = 0.13 (16% of range), and cup circumference:disc circumference, ICC = 0.90, TC = 0.12 (17% of range). Systematic bias between observers was within acceptable limits. CONCLUSIONS: Digital stereo disc photography and analysis provide repeatable measures of optic disc variables. The results compare favourably with ophthalmoscopic and stereophotographic methods of assessment of the optic disc. (+info)