The Effects of Study Design and Spectrum Bias on the Evaluation of Diagnostic Accuracy of Confocal Scanning Laser Ophthalmoscopy in Glaucoma

Medeiros, Felipe A.; Ng, Diana; Zangwill, Linda M.; Sample, Pamela A.; Bowd, Christopher; Weinreb, Robert N.

doi:10.1167/iovs.06-0618

Cited by 67 publications

(52 citation statements)

References 32 publications

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“…Such a design has been shown to inflate the actual diagnostic ability of a test. 30,31 Another limitation, in general to all studies in glaucoma is the lack of reference standard for diagnosing the disease. Our glaucoma cohort included patients with evidence of both structural changes in optic disc and correlating visual field changes.…”

Section: Discussionmentioning

confidence: 99%

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma

Rao

Jonnadula

Addepalli

et al. 2011

Eye

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Purpose To compare the diagnostic abilities of peripapillary retinal nerve fiber layer (RNFL) and macular inner retina (MIR) measurements by spectral domain optical coherence tomography (SD-OCT) in Indian eyes early glaucoma. Methods In an observational, cross-sectional study, 125 eyes of 64 normal subjects and 91 eyes of 59 early glaucoma patients underwent RNFL and MIR imaging with SD-OCT. Glaucomatous eyes had characteristic optic nerve and RNFL abnormalities and correlating visual field defects and a mean deviation of better than or equal to -6 dB on standard automated perimetry. Areas under the receiver operating characteristic curves (AUC), sensitivities at a fixed specificity and likelihood ratios (LRs) were estimated for all RNFL and MIR parameters. Results The AUCs for the RNFL parameters ranged from 0.537 for the temporal quadrant thickness to 0.821 for the inferior quadrant RNFL thickness. AUCs for the MIR parameters ranged from 0.603 for the superior minus inferior MIR thickness average to 0.908 for ganglion cell complex focal loss volume (GCC-FLV). AUC for the best MIR parameter (GCC-FLV) was significantly better (Po0.001) than that of the best RNFL parameter (inferior quadrant thickness). The sensitivities of these parameters at high specificity of 95%, however, were comparable (52.7% vs 58.2%). Evaluation of the LRs showed that outside normal limits results of most of the RNFL and MIR parameters were associated with large effects on the post-test probability of disease. Conclusion MIR parameters with RTVue SD-OCT were as good as the RNFL parameters to detect early glaucoma.

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Section: Discussionmentioning

confidence: 99%

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma

Rao

Jonnadula

Addepalli

et al. 2011

Eye

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“…In previous studies, normal subjects had no suspicious findings of disease and were generally required to have normal optic discs, whereas in our study, normal subjects had optic discs with a suspicious appearance, making it more difficult for the diagnostic test to differentiate them from diseased subjects. In fact, a recent study by Medeiros et al 10 evaluating the impact of design-related bias in studies of diagnostic tests in glaucoma found that studies with a case-control design including patients with well-established disease and a separate group of normal (unsuspected) control subjects resulted in substantial overestimation of the test's performance.…”

Section: Discussionmentioning

confidence: 99%

“…The final diagnosis based on longitudinal follow-up can then be used as a reference standard with which the results of the imaging instruments are to be compared. 10,11 In the present study, we compared the RNFL and optic disc topographic assessment by SLP and CSLO, respectively, to detect glaucomatous damage in patients suspected of having the disease. Long-term follow-up was used to establish diagnosis in these patients and as a reference standard for comparison of results.…”

Section: Nih-pa Author Manuscriptmentioning

confidence: 99%

“…One of these technologies, scanning laser polarimetry (SLP), provides quantitative estimates of RNFL thickness.1 , 2 Another, confocal scanning laser ophthalmoscopy (CSLO), evaluates the topography of the optic disc, although it also can provide indirect estimates of RNFL integrity.3 , 4 Numerous studies have evaluated and compared the ability of these instruments to discriminate patients with repeatable glaucomatous VF loss from healthy subjects.4 -8 However, estimates of diagnostic accuracy of imaging instruments obtained from these studies are not directly applicable to the evaluation of those patients suspected of having glaucoma without confirmed VF loss. 9,10 The conduct of studies evaluating glaucoma suspects has been limited by the inexistence of a perfect reference standard that could be used to diagnose disease at a single point in time without relying on VFs. Unfortunately, there are no sensitive and specific glaucoma biomarkers, and it is difficult, if not impossible, to ascertain the true diagnosis in a patient suspected of having glaucoma, based on a single evaluation.…”

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Comparison of Retinal Nerve Fiber Layer and Optic Disc Imaging for Diagnosing Glaucoma in Patients Suspected of Having the Disease

et al. 2008

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Purpose-To compare retinal nerve fiber layer (RNFL) and optic disc topographic imaging for detection of optic nerve damage in patients suspected of having glaucoma. Design-Observational cohort study.Participants-A cohort of 82 patients suspected of having glaucoma based on the appearance of the optic nerve.Methods-All patients were imaged using the GDx VCC scanning laser polarimeter and HRT (software version 3.0) confocal scanning laser ophthalmoscope. All patients had normal standard automated perimetry visual fields at the time of imaging and were classified based on history of documented stereophotographic evidence of progressive glaucomatous change in the appearance of the optic nerve occurring before the imaging sessions.Main Outcome Measures-Areas under the receiver operating characteristic (ROC) curves were used to evaluate the diagnostic accuracies of GDx VCC and the HRT.Results-Forty eyes with progressive glaucomatous optic nerve change were included in the glaucoma group, and 42 eyes without any evidence of progressive damage to the optic nerve followed untreated for an average time of 8.97±3.08 years were included in the normal group. The area under the ROC curve for the best parameter from GDx VCC (nerve fiber indicator [NFI]) was significantly larger than that of the best parameter from the HRT (rim volume) (0.83 vs. 0.70; P = 0.044). The NFI parameter also had a larger ROC curve area than that of the contour line-independent parameter glaucoma probability score (0.83 vs. 0.68; P = 0.023). Assuming borderline results as normal, the Moorfields regression analysis classification had a sensitivity of 48% for specificity of 69%. For a similar specificity (70%), the parameter NFI had a significantly larger sensitivity (83%) (P = 0.003).Conclusions-Retinal nerve fiber layer imaging with GDx VCC had a superior performance versus topographic optic disc assessment with the HRT for detecting early damage in patients suspected of having glaucoma. For glaucoma diagnosis, these results suggest that GDx VCC may offer advantage over the HRT when these tests are combined with clinical examination of the optic nerve.To diagnose disease, a clinician integrates the constellation of symptoms and/or signs of a presenting patient and then assigns a level of certainty regarding its presence. In the case of glaucoma evaluation, the process generally starts with the medical interview and history. It is NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript followed by clinical examination, which generally includes slit-lamp examination, intraocular pressure (IOP) measurement, and optic nerve examination. After this information is collected, the clinician hypothesizes about the chance that glaucoma is present and can order additional tests, such as the visual field (VF).It is not unusual for a patient to present with suspicious appearance of the optic disc and normal or inconclusive VF tests. In this situation, additional testing, such as optic disc and/or retinal nerve fiber layer (RNFL) imaging,...

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“…It is not possible to rule-out the diagnosis of glaucoma completely in suspect eyes unless followed up for a reasonable period of time. Medeiros et al 39 have therefore advocated the use of progressive optic disc change over follow-up examinations as the reference standard for glaucoma. This possibility of including a few preperimetric glaucoma cases in the control cohort, affecting the comparison of diagnostic abilities between SDOCT and GDx ECC should therefore be kept in mind.…”

Section: Discussionmentioning

confidence: 99%

Retinal nerve fiber layer evaluation of spectral domain optical coherence tomograph and scanning laser polarimeter to diagnose glaucoma

Rao

Yadav

Addepalli

et al. 2014

Eye

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Purpose To compare the abilities of retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting glaucoma. Methods In a cross-sectional study, 215 eyes of 165 subjects (106 eyes of 79 glaucoma patients and 109 eyes of 86 controls) referred by general ophthalmologists for glaucoma evaluation underwent RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT to discriminate glaucoma eyes from control eyes was compared with that of GDx ECC using area under operating characteristic curves (AUCs), sensitivities at fixed specificities, and likelihood ratios (LRs). Results AUC of the average RNFL thickness of SDOCT to differentiate glaucoma from control eyes (0.868) was comparable (P ¼ 0.32) to that of GDx ECC (0.855). Sensitivity at 95% specificity was 63.2% for average RNFL thickness of SDOCT and 48.1% for the average RNFL measurement of GDx ECC. LRs of outside normal limits category of SDOCT parameters ranged between 5.6 and 7.7 while the same of GDx ECC parameters ranged between 3.1 and 3.7. LRs of within normal limits category of SDOCT parameters ranged between 0.18 and 0.24 while the same of GDx ECC parameters ranged between 0.20 and 0.32. Conclusion Though AUCs and sensitivities at fixed specificities were comparable between the RNFL parameters of SDOCT and GDx ECC in diagnosing glaucoma, LRs indicated that the RNFL parameters of SDOCT were better in 'ruling in' glaucoma.

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The Effects of Study Design and Spectrum Bias on the Evaluation of Diagnostic Accuracy of Confocal Scanning Laser Ophthalmoscopy in Glaucoma

Cited by 67 publications

References 32 publications

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma

Comparison of Retinal Nerve Fiber Layer and Optic Disc Imaging for Diagnosing Glaucoma in Patients Suspected of Having the Disease

Retinal nerve fiber layer evaluation of spectral domain optical coherence tomograph and scanning laser polarimeter to diagnose glaucoma

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