Diagnostic performance of modern imaging instruments in glaucoma screening.

AIM: To evaluate the applicability of imaging devices (spectral-domain optical coherence tomography (Cirrus SD-OCT), scanning laser polarimetry (GDx) and scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph, HRT3)) for glaucoma screening in a middle-aged unselected population. METHODS: Participants of the population-based Northern Finland Birth Cohort Eye Study, aged 45 to 49 years, underwent a comprehensive eye examination including modern imaging with five methods (retinal nerve fibre layer (RNFL) and macular ganglion cell layer +inner plexiform layer (GCIPL) analysis and their combination with SD-OCT, GDx and HRT). The performance of the automated classification of the imaging devices was assessed using a clinical glaucoma diagnosis as reference, that is, the '2 out of 3' rule based on the evaluation of optic nerve head and RNFL photographs and visual fields. RESULTS: We examined 6060 eyes of 3039 subjects; in the clinical evaluation, glaucomatous damage was found in 33 subjects (1.1%) in 43 eyes. The following sensitivities were obtained; RNFL analysis (53%), GCIPL analysis (50%), OCT combination analysis (61%), GDx (56%) and HRT (31%) with corresponding specificities of 95%, 92%, 90%, 88% and 96%. The area under the curve values were 0.76, 0.73, 0.75, 0.75 and 0.73, respectively. Post-test probabilities of glaucoma after positive imaging finding with each of these methods in this unselected population were 11%, 7%, 6%, 5% and 7%, respectively. CONCLUSION: Screening capabilities of the OCT, GDx and HRT were rather similar. The accuracy of all evaluated parameters was only moderate and thus screening with these parameters alone is not reliable.

Prevalence of glaucoma in the Northern Finland Birth Cohort Eye Study.

PURPOSE: To report the prevalence of glaucoma in the Northern Finland Birth Cohort (NFBC) Eye Study. METHODS: Subjects of the population-based Northern Finland 1966 Birth Cohort (NFBC), aged 45-49 years at the time of the field examination, were randomized to eye screening (50%) and control (50%) groups. The eye examination protocol included best corrected visual acuity (BCVA), measurements of intraocular pressure and central corneal thickness, Humphrey 24-2 perimetry, stereoscopic optic nerve head (ONH) and retinal nerve fibre layer (RNFL) photography and imaging with optical coherence tomography (OCT), scanning laser polarimetry (GDx) and scanning laser ophthalmoscopy (HRT). The diagnosis of glaucoma was made by two independent general ophthalmologists and three independent glaucoma experts based on the evaluation of the ONH and RNFL photographs and the visual fields. RESULTS: Totally, 10 321 subjects of the NFBC main study were alive in Finland in 2011, and they were randomized to the NFBC Eye Study group (n = 5155) and the control group (n = 5166). Of the randomized subjects, 3039 of 5155 (59%) responded and had sufficient data for the study. Glaucoma was suspected in 172 subjects (5.7%) at the first phase of the evaluation protocol. The interobserver agreement between two screening ophthalmologists was moderately good (kappa value 0.54 [95% confidence intervals (CI) 0.46-0.61]). Finally, definite glaucoma was found in 33 subjects (1.1% [95% CI 0.8-1.5]). CONCLUSION: The study provides up-to-date information on the prevalence of glaucoma in a middle-aged Caucasian population in Finland. The baseline data reported here allows the evaluation of the cost-effectiveness of screening later on.

Relationship between retinal vessel diameter with both retinal nerve fibre layer thickness and optic nerve head parameters in middle-aged Caucasians: the Northern Finland Birth Cohort Eye study.

PURPOSE: To study the normal relationship between retinal vessel diameter (RVD) with retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters in a cohort of middle-aged Caucasians. METHODS: We investigated 3070 individuals (6140 eyes). Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were measured in the right eye using a semi-automated computer-assisted program. Retinal nerve fibre layer (RNFL) thickness and ONH parameters were assessed with Heidelberg retinal tomography (HRT). RESULTS: Data from 2217 persons were analysed including RNFL, CRAE, CRVE, sex, body mass index, mean arterial pressure, diabetes status, smoking status, optic disc area, rim area, spherical refraction and intraocular pressure. A larger RVD was associated with a thicker mean global RNFL thickness especially in global and inferior segments of the retina and with larger optic discs. Each 10 µm increase in the retinal arteriolar calibre was associated with a 5.58 µm increase in mean global RNFL thickness; the corresponding value for a 10 µm increase in venular calibre was 3.79 µm (p < 0.001 for both). Retinal venular calibre displayed consistent associations with RNFL thickness in both genders (p < 0.001 for all), whereas the association of arteriolar calibre and RNFL was more prominent in men (p < 0.001). CONCLUSION: We found strong associations between larger RVD and thicker RNFL in all subjects. This study helps to clarify the association between RVD, RNFL thickness and ONH parameters and provides normal values for middle-aged Caucasians that will help in future studies investigating the role of vascular aetiology in systemic and eye diseases.