Cross-Camera External Validation for Artificial Intelligence Software in Diagnosis of Diabetic Retinopathy.

Aims: To investigate the applicability of deep learning image assessment software VeriSee DR to different color fundus cameras for the screening of diabetic retinopathy (DR). Methods: Color fundus images of diabetes patients taken with three different nonmydriatic fundus cameras, including 477 Topcon TRC-NW400, 459 Topcon TRC-NW8 series, and 471 Kowa nonmyd 8 series that were judged as "gradable" by one ophthalmologist were enrolled for validation. VeriSee DR was then used for the diagnosis of referable DR according to the International Clinical Diabetic Retinopathy Disease Severity Scale. Gradability, sensitivity, and specificity were calculated for each camera model. Results: All images (100%) from the three camera models were gradable for VeriSee DR. The sensitivity for diagnosing referable DR in the TRC-NW400, TRC-NW8, and non-myd 8 series was 89.3%, 94.6%, and 95.7%, respectively, while the specificity was 94.2%, 90.4%, and 89.3%, respectively. Neither the sensitivity nor the specificity differed significantly between these camera models and the original camera model used for VeriSee DR development (p = 0.40, p = 0.065, respectively). Conclusions: VeriSee DR was applicable to a variety of color fundus cameras with 100% agreement with ophthalmologists in terms of gradability and good sensitivity and specificity for the diagnosis of referable DR.

El oftalmoscopio sin espejo de Welch-Allyn / The mirrorless ophthalmoscope de Welch-Allyn

No disponible

Ability of MultiColor scanning laser ophthalmoscope to detect non-glaucomatous retinal nerve fiber layer defects in eyes with retinal diseases.

PURPOSE: To compare the ability of ocular fundus images obtained by Spectralis MultiColor scanning laser ophthalmoscope (MC-SLO) to that obtained by conventional color fundus images (CF) in detecting non-glaucomatous nerve fiber layer defects (NFLDs). METHODS: A cross-sectional, retrospective study. Patients with retinal diseases who had ocular examination with both the MC-SLO and CF instruments at the Kagoshima University from December 2016 to February 2017 were studied. Eyes that had NFLDs with non-glaucomatous optic discs were analyzed. The visibility of the NFLDs was classified into three grades: grade 0, not visible; grade 1, barely visible; and grade 2, clearly visible. The NFLD grade for blue, green, and red scanning lights of the MC-SLO, merged images with three wavelengths and the color and red-free images were determined by two ophthalmologists. These scores were compared by Steel-Dwass tests. RESULTS: Thirty-one eyes of 26 patients with a mean age of 63.1 ± 11.2 years were studied. There were 14 eyes with diabetic retinopathy, 11 eyes with age-related macular degeneration, 3 eyes with a branch retinal vein occlusion, and 3 eyes with an epiretinal membrane/macular hole. Both the intra-rater (0.631-0.790) and inter-rater (0.637-0.733) agreements were good. NFLDs were detected by the blue wavelength in all cases and by green wavelength and merged wavelengths in 90.3% of the images. The mean NFLD grade was 1.58 ± 0.49 for blue light images, 1.13 ± 0.54 for green light images, 0.07 ± 0.24 for red light images, and 1.16 ± 0.56 for merged images. The NFLD score for blue wavelength was significantly higher than that for green and red wavelength images (P < 0.05 and P < 0.01) but not significantly higher than that for the merged images. NFLDs were detected in 12 eyes (38.7%) in the color images and 16 eyes (51.6%) in the red-free images. The NFLD score for the CF and the red-free image was 0.41 ± 0.55 and 0.70 ± 0.67 which is significantly lower than that of blue MC-SLO images. CONCLUSION: The images obtained by MC-SLO are superior to that obtained by CF in detecting NFLDs in eyes with retinal diseases. We recommend MC-SLO imaging to screen for NFLDs in eyes with retinal diseases.

Combined high contrast and wide field of view in the scanning laser ophthalmoscope through dual detection of light paths.

We demonstrate a multimode detection system in a scanning laser ophthalmoscope (SLO) that enables simultaneous operation in confocal, indirect, and direct modes to permit an agile trade between image contrast and optical sensitivity across the retinal field of view to optimize the overall imaging performance, enabling increased contrast in very wide-field operation. We demonstrate the method on a wide-field SLO employing a hybrid pinhole at its image plane, to yield a twofold increase in vasculature contrast in the central retina compared to its conventional direct mode while retaining high-quality imaging across a wide field of the retina, of up to 200 deg and 20 µm on-axis resolution.

Improving Retinal Image Quality Using Registration with an SIFT Algorithm in Quasi-Confocal Line Scanning Ophthalmoscope.

When high-magnification images are taken with a quasi-confocal line scanning ophthalmoscope (LSO), the quality of images always suffers from Gaussian noise, and the signal to noise ratio (SNR) is very low for a safer laser illumination. In addition, motions of the retina severely affect the stabilization of the real-time video resulting in significant distortions or warped images. We describe a scale-invariant feature transform (SIFT) algorithm to automatically abstract corner points with subpixel resolution and match these points in sequential images using an affine transformation. Once n images are aligned and averaged, the noise level drops by a factor of [Formula: see text] and the image quality is improved. The improvement of image quality is independent of the acquisition method as long as the image is not warped, particularly severely during confocal scanning. Consequently, even better results can be expected by implementing this image processing technique on higher resolution images.

Comparing the utility of the non-mydriatic fundus camera to the direct ophthalmoscope for medical education.

Visualization of the fundus is an important component of any ophthalmologic exam. Students are taught to visualize the fundus using a direct handheld ophthalmoscope. However, this device has many limitations, which may be a detriment to medical education and patient care. The invention of the non-mydriatic automatic fundus camera could significantly improve medical education. Our study examined the ability of a group of 5 medical students to visualize pathology and form a diagnosis with a traditional handheld ophthalmoscope and an automatic fundus camera. With the direct ophthalmoscope, none of the students were able to visualize the macula, a crucial aspect of the ophthalmologic exam. With the automatic fundus camera, all students were able to visualize the fundus. The latter modality also increased the proportion of students that was able to correctly diagnose the patients with diabetic retinopathy, 100% vs 40%. On average, students were also more confident in their ability to visualize basic retinal anatomy with the automatic fundus camera, 9.6/10 vs 6.4/10. Thus, incorporating the non-mydriatic automatic fundus camera into medical education, alongside the handheld ophthalmoscope, has the potential to improve both learning outcomes and patient care.

Prevalence of disc cupping in non-glaucomatous eyes.

This study assessed optic disc size and cupping, using a commercially available ophthalmoscope, in order to show norms of these values for clinical practice. Subjects were office-workers referred from their respective workplaces for a routine medical examination, which included eye examination. The optic disc size was classified as small, medium or large, for having a diameter < 1.0, 1.0-1.5, or > 1.5 times (respectively) the diameter of the ophthalmoscope's selected light spot on the posterior pole. The cupping was classified as the ratio of the vertical cupping diameter and the vertical disc diameter on a relative decimal scale from 0.0 to 1.0.This study included 184 subjects with a mean age of 40.5 ± 9.5 years; 149 (81%) were males. Their mean ocular pressure was 12.4 ± 1.5 mmHg (range 10-17 mmHg). There was a high correlation between optic disc sizes and cupping in the right and left eyes (Pearson Correlation r = 0.866, p < 0.001); therefore, for simplicity only the data for right eyes are presented. According to our definition, the optic discs in these eyes comprised 27 (14.7%) small, 141 (76.6%) medium and 16 (8.7%) large. The small optic discs were rarely cupped, and the large optic discs were always cupped. Optic disc cupping greater than 0.7 was rarely found and should be suspect of glaucoma. Clinical doctors should be aware of this and refer those subjects with abnormal cupping to the specialist.

Prevalence of disc cupping in non-glaucomatous eyes

This study assessed optic disc size and cupping, using a commercially available ophthalmoscope, in order to show norms of these values for clinical practice. Subjects were office-workers referred from their respective workplaces for a routine medical examination, which included eye examination. The optic disc size was classified as small, medium or large, for having a diameter < 1.0, 1.0-1.5, or > 1.5 times (respectively) the diameter of the ophthalmoscope's selected light spot on the posterior pole. The cupping was classified as the ratio of the vertical cupping diameter and the vertical disc diameter on a relative decimal scale from 0.0 to 1.0.This study included 184 subjects with a mean age of 40.5 ± 9.5 years; 149 (81%) were males. Their mean ocular pressure was 12.4 ± 1.5 mmHg (range 10-17 mmHg). There was a high correlation between optic disc sizes and cupping in the right and left eyes (Pearson Correlation r = 0.866, p < 0.001); therefore, for simplicity only the data for right eyes are presented. According to our definition, the optic discs in these eyes comprised 27 (14.7%) small, 141 (76.6%) medium and 16 (8.7%) large. The small optic discs were rarely cupped, and the large optic discs were always cupped. Optic disc cupping greater than 0.7 was rarely found and should be suspect of glaucoma. Clinical doctors should be aware of this and refer those subjects with abnormal cupping to the specialist.

Este estudio fue concebido para desarrollar normas clínicas sobre el tamaño y la excavación de la papila usando un simple oftalmoscopio en una población emétrope sin glaucoma. Los sujetos fueron oficinistas enviados al Centro Médico San Luis para un chequeo general de salud que incluye el examen oftalmológico. El tamaño de la papila o disco óptico fue clasificado en tres diámetros (pequeño, mediano y grande) comparando con el tamaño de la proyección retinal de la luz de un oftalmoscopio de bolsillo. La excavación papilar fue clasificada como la relación entre el diámetro horizontal de la excavación y el diámetro horizontal de la papila en escala decimal de 0.0 a 1.0. El estudio incluye 184 sujetos (edad media de 40.5 ± 9.5 años) y 149 (81%) fueron varones. Su presión ocular promedio fue de 12.4 ± 1.5 mmHg (entre 10-17 mmHg). La correlación tanto de los tamaños de disco óptico como de su excavación, fue alta entre ambos ojos (Correlación de Pearson, r = 0.866, p < 0.001) de modo que se presentan solamente datos de los ojos derechos. Según nuestra definición de tamaños papilares hubo 27 (14.7%) papilas pequeñas, 141 (76.6%) medianas y 16 (8.7%) grandes. Las papilas pequeñas rara vez tuvieron excavación y las grandes estuvieron siempre excavadas. Fue raro hallar papilas ópticas con una excavación mayor a 0.7, las que deberían hacer sospechar una lesión por glaucoma. Los clínicos avezados en oftalmoscopia deberían tener esto en cuenta para referir los sujetos con excavaciones grandes al especialista para su estudio oftalmológico.

The reliability of parafoveal cone density measurements.

BACKGROUND: Adaptive optics scanning light ophthalmoscopy (AOSLO) enables direct visualisation of the cone mosaic, with metrics such as cone density and cell spacing used to assess the integrity or health of the mosaic. Here we examined the interobserver and inter-instrument reliability of cone density measurements. METHODS: For the interobserver reliability study, 30 subjects with no vision-limiting pathology were imaged. Three image sequences were acquired at a single parafoveal location and aligned to ensure that the three images were from the same retinal location. Ten observers used a semiautomated algorithm to identify the cones in each image, and this was repeated three times for each image. To assess inter-instrument reliability, 20 subjects were imaged at eight parafoveal locations on one AOSLO, followed by the same set of locations on the second AOSLO. A single observer manually aligned the pairs of images and used the semiautomated algorithm to identify the cones in each image. RESULTS: Based on a factorial study design model and a variance components model, the interobserver study's largest contribution to variability was the subject (95.72%) while the observer's contribution was only 1.03%. For the inter-instrument study, an average cone density intraclass correlation coefficient (ICC) of between 0.931 and 0.975 was calculated. CONCLUSIONS: With the AOSLOs used here, reliable cone density measurements can be obtained between observers and between instruments. Additional work is needed to determine how these results vary with differences in image quality.

Accuracy of the Heidelberg Spectralis in the alignment between near-infrared image and tomographic scan in a model eye: a multicenter study.

PURPOSE: To evaluate temporal changes and predictors of accuracy in the alignment between simultaneous near-infrared image and optical coherence tomography (OCT) scan on the Heidelberg Spectralis using a model eye. DESIGN: Laboratory investigation. METHODS: After calibrating the device, 6 sites performed weekly testing of the alignment for 12 weeks using a model eye. The maximum error was compared with multiple variables to evaluate predictors of inaccurate alignment. Variables included the number of weekly scanned patients, total number of OCT scans and B-scans performed, room temperature and its variation, and working time of the scanning laser. A 4-week extension study was subsequently performed to analyze short-term changes in the alignment. RESULTS: The average maximum error in the alignment was 15 ± 6 µm; the greatest error was 35 µm. The error increased significantly at week 1 (P = .01), specifically after the second imaging study (P < .05); reached a maximum after the eighth patient (P < .001); and then varied randomly over time. Predictors for inaccurate alignment were temperature variation and scans per patient (P < .001). For each 1 unit of increase in temperature variation, the estimated increase in maximum error was 1.26 µm. For the average number of scans per patient, each increase of 1 unit increased the error by 0.34 µm. CONCLUSION: Overall, the accuracy of the Heidelberg Spectralis was excellent. The greatest error happened in the first week after calibration, and specifically after the second imaging study. To improve the accuracy, room temperature should be kept stable and unnecessary scans should be avoided. The alignment of the device does not need to be checked on a regular basis in the clinical setting, but it should be checked after every other patient for more precise research purposes.

Adaptive optics scanning laser ophthalmoscope-based microperimetry.

PURPOSE: To develop and test the application of an adaptive optics scanning laser ophthalmoscope (AOSLO) with eye tracking for high-resolution microperimetric testing. METHODS: An AOSLO was used to conduct simultaneous high-resolution retinal imaging and visual function testing in six normal subjects. Visual sensitivity was measured at test locations between the fovea and 5.0° eccentricity via an increment threshold approach using a 40-trial, yes-no adaptive Bayesian staircase procedure (QUEST). A high-speed eye tracking algorithm enabled real-time video stabilization and the delivery of diffraction-limited Goldmann I-sized stimuli (diameter = 6.5 arc min = ∼32 µm; λ = 680 nm) to targeted retinal loci for 200 ms. Test locations were selected either manually by the examiner or automatically using Fourier-based image registration. Cone spacing was assessed at each test location and sensitivity was plotted against retinal eccentricity. Finally, a 4.2 arc min stimulus was used to probe the angioscotoma associated with a blood vessel located at 2.5° eccentricity. RESULTS: Visual sensitivity decreases with eccentricity at a rate of -1.32 dB/deg (R = 0.60). The vertical and horizontal errors of the targeted stimulus delivery algorithm averaged 0.81 and 0.89 arc min (∼4 µm), respectively. Based on a predetermined exclusion criterion, the stimulus was successfully delivered to its targeted location in 90.1% of all trials. Automated recovery of test locations afforded the repeat testing of the same set of cones over a period of 3 months. Thresholds measured over a parafoveal blood vessel were 1.96 times higher (p < 0.05; one-tailed t-test) than those measured in directly adjacent retina. CONCLUSIONS: AOSLO-based microperimetry has the potential to test visual sensitivity with fine retinotopic precision. Automated recovery of previously tested locations allows these measures to be tracked longitudinally. This approach can be implemented by researchers interested in establishing the functional correlates of photoreceptor mosaic structure in patients with retinal disease.

Optic disc assessment in the emergency department: a comparative study between the PanOptic and direct ophthalmoscopes.

Optic disc assessment is an essential part of the neurological examination of acutely unwell patients. This study compares the PanOptic ophthalmoscope with the direct ophthalmoscope for accuracy of diagnosis and ease of use. Patient satisfaction was also compared for the two instruments. A single-masked prospective observational study was carried out. The authors showed that the PanOptic ophthalmoscope was more sensitive (p=0.03) and specific (p=0.03) than the direct ophthalmoscope. The PanOptic ophthalmoscope was preferred by both doctors (p=0.001) and patients (p=0.04) in terms of comfort and ease of use.

Factors affecting the variability of the Heidelberg Retina Tomograph III measurements in newly diagnosed glaucoma patients.

PURPOSE: To determine factors associated with the test-retest variability of optic nerve head (ONH) topography measurements with confocal scanning laser ophthalmoscopy (CSLO) in newly diagnosed glaucomatous patients. METHODS: Consecutive patients with newly diagnosed primary open-angle glaucoma were prospectively enrolled. Patients presenting with any ocular disease other than glaucoma were excluded. All patients underwent CSLO using the Heidelberg Retina Tomograph III (HRT-III) in one randomly selected eye (three consecutive scans; performed by the same examiner). For each Heidelberg Retina Tomograph III parameter, repeatability was assessed using within subject standard deviation (Sw) and coefficient of variation (CVw), repeatability coefficient (RC) and intraclass correlation coefficient (ICC). Scatter plots and regression lines were constructed to identify which factors influenced test-retest measurement variability. RESULTS: A total of 32 patients were included (mean age, 65.4 ± 13.8 years). Most patients were female (65%) and white (50%). Among all Heidelberg Retina Tomograph III parameters evaluated, rim area and mean cup depth had the best measurement repeatability. Vertical cup-to-disc ratio (CDR, as determined by optic disc stereophotograph examination) was significantly associated (R²=0.21, p<0.01) with test-retest measurement variability. Eyes with larger CDR showed less variable measurements. Other factors, including age, disc area, central corneal thickness and intraocular pressure were not significant (p>0.14). CONCLUSION: Heidelberg Retina Tomograph III showed good test-retest repeatability for all ONH topographic measurements, mainly for rim area and mean cup depth. Test-retest repeatability seemed to improve with increasing CDR. These findings suggest that HRT-III topographic measurements should be cautiously interpreted when evaluating longitudinally glaucoma patients with early structural damage (small CDR).

Factors affecting the variability of the Heidelberg Retina Tomograph III measurements in newly diagnosed glaucoma patients / Fatores associados com a variabilidade das medidas do Heidelberg Retina Tomograph III em pacientes com glaucoma recém-diagnosticados

PURPOSE: To determine factors associated with the test-retest variability of optic nerve head (ONH) topography measurements with confocal scanning laser ophthalmoscopy (CSLO) in newly diagnosed glaucomatous patients. METHODS: Consecutive patients with newly diagnosed primary open-angle glaucoma were prospectively enrolled. Patients presenting with any ocular disease other than glaucoma were excluded. All patients underwent CSLO using the Heidelberg Retina Tomograph III (HRT-III) in one randomly selected eye (three consecutive scans; performed by the same examiner). For each Heidelberg Retina Tomograph III parameter, repeatability was assessed using within subject standard deviation (Sw) and coefficient of variation (CVw), repeatability coefficient (RC) and intraclass correlation coefficient (ICC). Scatter plots and regression lines were constructed to identify which factors influenced test-retest measurement variability. RESULTS: A total of 32 patients were included (mean age, 65.4 ± 13.8 years). Most patients were female (65 percent) and white (50 percent). Among all Heidelberg Retina Tomograph III parameters evaluated, rim area and mean cup depth had the best measurement repeatability. Vertical cup-to-disc ratio (CDR, as determined by optic disc stereophotograph examination) was significantly associated (R²=0.21, p<0.01) with test-retest measurement variability. Eyes with larger CDR showed less variable measurements. Other factors, including age, disc area, central corneal thickness and intraocular pressure were not significant (p>0.14). CONCLUSION: Heidelberg Retina Tomograph III showed good test-retest repeatability for all ONH topographic measurements, mainly for rim area and mean cup depth. Test-retest repeatability seemed to improve with increasing CDR. These findings suggest that HRT-III topographic measurements should be cautiously interpreted when evaluating longitudinally glaucoma patients with early structural damage (small CDR).

OBJETIVO: Determinar os fatores associados à variabilidade (teste-reteste) das medidas topográficas da cabeça do nervo óptico (CNO) utilizando a oftalmoscopia confocal de varredura a laser (CSLO) em pacientes com glaucoma recém-diagnosticados. MÉTODOS: Neste estudo, pacientes com glaucoma primário de ângulo aberto recém-diagnosticados foram prospectivamente incluídos. Aqueles que apresentassem outras doenças oculares (exceto glaucoma) foram excluídos. Todos os pacientes incluídos no estudo foram submetidos à CSLO usando o aparelho Heidelberg Retina Tomograph III (HRT-III) em um olho aleatoriamente selecionado (três exames consecutivos realizados pelo mesmo examinador). Para cada parâmetro do Heidelberg Retina Tomograph III, a repetibilidade foi avaliada através dos seguintes indicadores: desvio padrão (DP) e coeficiente de variação (CV) individual, coeficiente de repetibilidade (CR) e coeficiente de correlação intraclasse (CCI). Diagramas de dispersão e linhas de regressão foram construídos para identificar quais fatores poderiam influenciar a variabilidade das medidas. RESULTADOS: Trinta e dois pacientes foram incluídos no estudo (idade média, 65,4 ± 13,8 anos). A maior parte era composta por mulheres (65 por cento) e pacientes brancos (50 por cento). Dentre os parâmetros de Heidelberg Retina Tomograph III avaliados, a área da rima e a profundidade média da escavação apresentaram os melhores valores de repetibilidade. A relação escavação/disco (E/D) vertical (baseada na análise de estereofotografia do disco óptico), foi significativamente associada (R²=0.21, p<0.01) com a variabilidade teste-reteste. Pacientes com relação E/D maiores apresentaram medidas menos variáveis. Outros fatores como idade, área do disco, espessura corneana central e pressão intraocular não foram significativas (p>0,14). CONCLUSÃO: O Heidelberg Retina Tomograph III mostrou boa repetibilidade (teste-reteste) para todos os parâmetros topográficos da CNO avaliados, principalmente em relação à área da rima e à profundidade média da escavação. A repetibilidade teste-reteste apresentou melhores resultados com o aumento da relação E/D. Esses achados sugerem que as medidas topográficas do Heidelberg Retina Tomograph III devem ser interpretadas com cautela quando avaliarmos longitudinalmente pacientes glaucomatosos com dano estrutural inicial (relação E/D menor).

Image quality characteristics of a novel colour scanning digital ophthalmoscope (SDO) compared with fundus photography.

PURPOSE: To establish a set of quality parameters for grading image quality and apply those to evaluate the fundus image quality obtained by a new scanning digital ophthalmoscope (SDO) compared with standard slide photography. METHODS: On visual analogue scales a total of eight image characteristics were defined: overall quality, contrast, colour brilliance, focus (sharpness), resolution and details, noise, artefacts and validity of clinical assessment. Grading was repeated after 4 months to assess repeatability. Fundus images of 23 patients imaged digitally by SDO and by Zeiss 450FF fundus camera using Kodak film were graded side-by-side by three graders. Lens opacity was quantified with the Interzeag Lens Opacity Meter 701. RESULTS: For all of the eight scales of image quality, good repeatability within the graders (mean Kendall's W 0.69) was obtained after 4 months. Inter-grader agreement ranged between 0.31 and 0.66. Despite the SDO's limited nominal image resolution of 720 x 576 pixels, the Zeiss FF 450 camera performed better in only two of the subscales - noise (p = 0.001) and artefacts (p = 0.01). Lens opacities significantly influenced only the two subscales 'resolution' and 'details', which deteriorated with increasing media opacities for both imaging systems. CONCLUSIONS: Distinct scales to grade image characteristics of different origin were developed and validated. Overall SDO digital imaging was found to provide fundus pictures of a similarly high level of quality as expert photography on slides.

[Meta-analysis of diagnostic capability of frequency-doubling technology (FDT) for primary glaucoma].

OBJECTIVE: To evaluate the overall diagnostic capabilities of frequency-doubling technology (FDT) in patients of primary glaucoma, with standard automated perimetry (SAP) and/or optic disc appearance as the gold standard. METHODS: A comprehensive electric search in MEDLINE, EMBASE, Cochrane Library, BIOSIS, Previews, HMIC, IPA, OVID, CNKI, CBMdisc, VIP information, CMCC, CCPD, SSreader and 21dmedia and a manual search in related textbooks, journals, congress articles and their references were performed to identify relevant English and Chinese language articles. Criteria for adaptability were established according to validity criteria for diagnostic research published by the Cochrane Methods Group on Screening and Diagnostic Tests. Quality of the included articles was assessed and relevant materials were extracted for studying. Statistical analysis was performed with Meta Test version 0.6 software. Heterogeneity of the included articles was tested, which was used to select appropriate effect model to calculate pooled weighted sensitivity and specificity. Summary Receiver Operating Characteristic (SROC) curve was established and the area under the curve (AUC) was calculated. Finally, sensitivity analysis was performed. RESULTS: Fifteen English articles (21 studies) of 206 retrieved articles were included in the present study, with a total of 3172 patients. The reported sensitivity of FDT ranged from 0.51 to 1.00, and specificity from 0.58 to 1.00. The pooled weighted sensitivity and specificity for FDT with 95% confidence intervals (95% CI) after correction for standard error were 0.86 (0.80 - 0.90), 0.87 (0.81 - 0.91), respectively. The AUC of SROC was 93.01%. Sensitivity analysis demonstrated no disproportionate influences of individual study. CONCLUSIONS: The included articles are of good quality and FDT can be a highly efficient diagnostic test for primary glaucoma based on Meta-analysis. However, a high quality perspective study is still required for further analysis.

The effectiveness of the Heidelberg Retina Tomograph and laser diagnostic glaucoma scanning system (GDx) in detecting and monitoring glaucoma.

OBJECTIVES: To determine the potential of optic nerve head tomography [Heidelberg Retina Tomograph (HRT)] and scanning laser polarimetry (GDx) for identifying patients with glaucomatous visual field loss. DESIGN: Examinations were performed with the HRT, GDx and Humphrey Field Analyzer (HFA). Glaucoma was defined by the presence of a field defect. Patients within the cross-sectional groups underwent a single examination, whereas patients in the longitudinal groups were examined 6 monthly, for an average of 3.5 years. SETTING: Manchester Royal Eye Hospital, UK. PARTICIPANTS: Patients with primary open angle glaucoma (POAG) or who were at risk of developing glaucoma. INTERVENTIONS: The diagnostic accuracies of the HRT and GDx were compared; specificity was set at 95%. The rate of change was determined by linear regression. To estimate the clinical application of the instruments, the proportion of an unselected group of patients on whom the examinations could be performed was calculated. Additionally, the time taken to perform and process each examination was measured. MAIN OUTCOME MEASURES: The ability of the techniques to identify cases showing deterioration. The level of agreement and applicability of the techniques. Time taken to perform and process each examination. RESULTS: From the cross-sectional group, the maximum sensitivities of the HRT and GDx were 59% and 45%, respectively (at 95% specificity). From the two longitudinal cohorts, the level of agreement between the three instruments for identification of the development and deterioration of POAG was low. The applicability of the techniques was 80% (HRT), 88% (GDx) and 98% (HFA). The length of time to perform a full examination with each instrument was 12.3, 11.8 and 28.3 minutes, respectively. Agreement of HRT and GDx parameters between and within observers was largely good. CONCLUSIONS: There is poor agreement for detection of glaucoma between the HFA, HRT and GDx. The techniques are amenable to use in the clinical environment, but no single examination has sufficient diagnostic precision to be used in isolation; also, the imaging techniques were not universally applicable. Neither the HRT nor GDx should be viewed as a replacement for visual field examination. Further research is needed into why most patients within the longitudinal arms of the study showed very little deterioration and into determining aspects of the structure versus function relationship in glaucoma that may explain why any one technique fails to detect a proportion of cases.

A novel instrument for assessing the retinal red reflex for non-ophthalmic health professionals.

BACKGROUND: The direct ophthalmoscope is the standard instrument for assessing retinal red reflexes when screening for cataract, however, it is expensive and often not available to non-ophthalmic health professionals. The pen torch ophthalmoscope is a new economic alternative for this purpose. This study aimed to determine its accuracy in assessing retinal red reflexes and to compare it to the direct ophthalmoscope. It is anticipated that this instrument will be useful in detecting both congenital and adult type cataracts. METHODS: Eighteen health professionals evaluated the retinal red reflexes of 68 subjects at the Dunedin Hospital Eye Clinic with both the direct ophthalmoscope and the pen torch ophthalmoscope. Three groups of seven, six and five observers assessed both eyes of 24, 21 and 23 subjects, respectively, resulting in 1,574 examinations. RESULTS: Compared to the direct ophthalmoscope, the pen torch ophthalmoscope exhibited lower sensitivity (68 per cent versus 75 per cent), but higher specificity (72 per cent versus 63 per cent) and lower over-referral (false positive) rates by nine per cent. The positive predictive value in respect to identifying for cataract was better for the pen torch ophthalmoscope (71 per cent) than for the direct ophthalmoscope (66 per cent), while the negative predictive value was slightly worse (70 per cent and 73 per cent, respectively). When compared to the direct ophthalmoscope, 15/18 observers felt the pen torch ophthalmoscope was accurate enough, one felt it was just as good and two did not respond. CONCLUSIONS: This pilot study demonstrates that the pen torch ophthalmoscope is comparable to the direct ophthalmoscope in detecting abnormal retinal red reflexes in adults with cataracts. At six per cent of the cost of a direct ophthalmoscope, it may appeal to non-ophthalmic health professionals in developed and developing countries. It may also increase the frequency of screening for cataract in children and adults. Further development and study of this pen torch ophthalmoscope prototype is warranted.

Intraobserver repeatability of macula measurements by confocal scanning laser tomography.

PURPOSE: To assess the repeatability of macula measurements provided by the Heidelberg Retina Tomograph II (HRT II) in normal subjects, patients with diabetic macular edema (DME), and patients with choroidal neovascularization (CNV). DESIGN: Prospective, observational case. SETTING: Institutional-based study. PATIENT POPULATION: Ten normal eyes, 14 eyes with DME, and 14 eyes with CNV. OBSERVATIONAL PROCEDURE: Three scans within a single day. An additional three scans of each of the 10 normal eyes on a different day. MAIN OUTCOME MEASURES: Bland and Altman analysis for a 0.25 mm, 0.50 mm, and 0.75 mm radius circle. RESULTS: Variability and repeatability of the measurements were not related to circle size for either group of patients. Coefficient of variability values of the normal group and a 0.50-mm radius circle were 17%, 5.7%, and 6.1% for mean surface height, signal width, and edema index, respectively. The corresponding values were 15.6%, 10%, and 10% for the DME group, and 10.5%, 7.4%, and 8.5% for the CNV group. The 95% confidence interval of the difference between single observations across days of the normal group was +/-106 microm, +/-80 microm, and +/-0.10 for mean surface height, signal width, and edema index, respectively. When three scans were combined, the corresponding values were +/-61.5 microm, +/-46.7 microm, and +/-0.06. CONCLUSIONS: The repeatability and variability of measurements of normal subjects, patients with DME, and patients with CNV were determined. Differences between the three groups exist and are important for diagnosing a pathologic condition or measuring the effect of various treatments.

Adjustment of guidelines for exposure of the eye to optical radiation from ocular instruments: statement from a task group of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

A variety of optical and electro-optical instruments are used for both diagnostic and therapeutic applications to the human eye. These generally expose ocular structures to either coherent or incoherent optical radiation (ultraviolet, visible, or infrared radiation) under unique conditions. We convert both laser and incoherent exposure guidelines derived for normal exposure conditions to the application of ophthalmic sources.