ABSTRACT
OBJECTIVE: To report the frequency and severity of optical coherence tomography (OCT) retinal thickness measurement errors and to describe parameters that predict these errors. DESIGN: Observational case series. PARTICIPANTS: Two hundred consecutive patients undergoing OCT imaging. METHODS: One eye (primary) from each of 200 consecutive patients undergoing Stratus OCT imaging (Carl Zeiss Meditec, Dublin, CA) with radial lines or fast macular thickness-based acquisition protocols was selected for review by 2 graders. On each of the line scans, graders evaluated the position of the automated retinal boundary lines (inner retinal surface and retinal pigment epithelium band) used by the OCT machine for thickness calculations and graded the positioning on a 6-point subjective, categorical error scale to generate an error score. The presence of thickness errors was correlated with various parameters, including the analysis confidence assessment reported by the OCT software, disease diagnosis, retinal morphologic features, the foveal center thickness standard deviation (FCTSD), and the FCTSD-to-foveal center thickness (FCT) ratio. MAIN OUTCOME MEASURE: Average OCT retinal thickness error score. RESULTS: Errors of retinal boundary detection and thickness measurement were observed in 92% of eyes, but were severe in only 13.5% of eyes. The identification of an error or low analysis confidence by the OCT software was strongly associated with the severity of the retinal thickness errors. A higher FCTSD-to-FCT ratio and presence of subretinal fluid also were associated with more severe errors. Retinal cysts and a diagnosis of retinal vascular disease such as diabetic macular edema were less likely to be associated with significant errors. CONCLUSIONS: Retinal thickness measurement errors occur frequently with current OCT segmentation and analysis algorithms. Severe errors are more frequent in eyes with subretinal pathologic features, but generally are detected by the OCT software. A high FCTSD-to-FCT ratio (>0.1) also may alert the clinician to the possibility of thickness errors. Clinical studies, particularly those pertaining to subretinal diseases, should consider these errors when incorporating OCT imaging in the study design.
Subject(s)
Diagnostic Errors , Diagnostic Techniques, Ophthalmological , Retina/pathology , Retinal Diseases/diagnosis , Tomography, Optical Coherence , HumansABSTRACT
The present study compared differences in subjective and objective performance in completely-in-the-canal (CIC) hearing aids with conventional uniform 1.5 mm parallel vents and another with a reverse horn vent where the diameter increased from 1.5 mm on the lateral faceplate to 3 mm on the medial opening of the hearing aid. Nine hearing-impaired persons with a high-frequency hearing loss participated. The test battery included unaided in situ thresholds, amount of available gain before feedback, speech in quiet, speech in noise (HINT), subjective ratings of hollowness and tolerance, objective measures of the occlusion effect, and real-ear aided response. Results showed less available gain before feedback but less occlusion effect for subjective ratings and objective measures with the reverse horn vent. This type of vent design may be useful to increase the effective vent diameter of custom (including CIC) hearing aids.
Subject(s)
Ear Canal/physiology , Hearing Aids , Hearing Loss, High-Frequency/rehabilitation , Speech Perception , Aged , Audiometry, Speech , Auditory Threshold , Equipment Design , Female , Humans , Male , Middle AgedABSTRACT
Se presenta el caso de un paciente varón de 26 años, con cuadro de fiebre, ascitis y dolor abdominal, infectado con el virus de la Inminodeficiencia Humana (HIV). Los estudios de ayuda diagnóstica (laboratorio, Rayos X, ecografía, etc.) fueron en su totalidad negativos; pero dada la alta incidencia de tuberculosis en nuestro medio, se planteó el dignóstico presuntivo de peritonitis tuberculosa. La respuesta clínica al tratamiento específico fue excelente, siendo dado de alta en buen estado general. Se efectuó el seguimiento del paciente durante tres meses hasta su reingreso, trece días después falleció con un cuadro de meningitis, cuya etiología no se pudo confirmar
