ABSTRACT
BackgroundGlaucoma is an optic neuropathy caused by structural damage of the optic nerve,and its early diagnosis is critical for arresting the irreversible damage of visual function. Optical coherence tomography (OCT) allows an early diagnosis of glaucoma by the measurements of the optic disc and retinal nerve fiber parameters. Objective This study was carried out to evaluate the effects of optic disc tomography and the measurement of the retinal nerve fiber layer (RNFL)thickness by spectral-domain OCT on the diagnosis of glaucomatous eye. MethodsIt was a noninterventional, cross-sectionalstudy. The optic disctopographic parameters and total and regional RNFL thickness were measured by RTVue OCT in 62 normal eyes and 67 glaucomatous eyes. The area under the receiver operating characteristic curve( ROC ) was used to assess the ability to differentiate glaucoma eyes from normal eyes of each testing parameter. This trial complied with the Helsinki Declaration and was approved by the Clinical Trial Ethic Committee of Beijing TongrenHospital. All of the participants signed the written informed consent before any medical examination. Results In the comparison of demography ,the ages of patients, the mean deficiency( MD ) and pattern standard difference( PSD ) of perimetry were obviously larger in the glaucoma group, primary open angle glaucoma ( POAG ) group and primary closure-angle glaucoma(PACG) group than those of normal controls( P＜0. 01 ). No significant differences were found in the disc area between a total glaucoma group, POAG group or PACG group and normal group ( P =0. 101,0. 741 and 0. 652, respectively) ;however, the average RNFL thickness between normal eyes and glaucomatous eyes were significantly different( 109. 758 μm versus 79. 539 μm, P＜0. 01 ). Among the eight regions around the optic disc, the thickest RNFL located at the inferotemporal( 150. 109 μm) and superotemporal( 146. 105 μm) regions in normal eyes,and at the superotemporal( 104. 354 μm) and inferotemporal( 102. 436 μm) regions in glaucomatous eyes. Both in normal and glaucomatous eyes,the thinnest RNFL located at the nasal(NU+NL) and temporal(TU + TL) regions. For optic disc topographic parameters,the highest ROC were observed in rim volume( ROC--0. 850,0. 841 and 0. 862 in total glaucoma,POAG and PACG, respectively) and vertical cup/disc ratio( ROC =0. 840,0. 849 and 0. 830 in total glaucoma,POAG and PACG,respectively), and the sensitivities for specificity cutoff set at 80％ were 73.1％ and 76. 1％ in total glaucoma,73.0％ and 81.1％ in POAG and 73.3％ and 70.0％ in PACG, respectively. For RNFL thickness ,the highest ROC was observed in average RNFL( ROC =0. 925,0. 910 and 0. 942 in total glaucoma, POAG and PACG,respectively) ,and the sensitivities for specificity cutoff set at 80％ were 89. 6％ ,89.2％ and 90. 0％ in total glaucoma,POAG and PACG, respectively. Among the eight regions around the optic disc, RNFL thickness of region IT achieved the highest ROC, RNFL thickness of region TU and TL had the lowest ROC. Conclusions RTVue OCT appears to be of fair discriminating ability in distinguishing normal from glaucomatous eyes. RTVue OCT shows promise for the diagnosis of glaucoma.
ABSTRACT
<p><b>BACKGROUND</b>Measurement of anterior segment parameters plays an important role in diagnosis and treatment of glaucoma. The objective of this study was to evaluate the repeatability and reproducibility of anterior chamber volume (ACV) measurements with rotating scheimpflug camera (RSC) and to examine agreement with anterior segment optical coherence tomography (AS-OCT).</p><p><b>METHODS</b>Thirty nine healthy normal subjects were recruited from the Eye Center of Tongren Hospital. ACV was measured using RSC and AS-OCT in a randomly selected eye for each subject. For RSC measurements, both automatic and manual ACV measurements and 2 independent operators' ACV measurements were obtained. All subjects were invited for 3 visits within a week to evaluate repeatability and reproducibility of ACV measurement by RSC. Agreement was evaluated between RSC and AS-OCT.</p><p><b>RESULTS</b>Good repeatability and reproducibility were found for both automatic and manual ACV measurements obtained by RSC. For intrasession repeatability, coefficient of variation (CVw) and intraclass correlation coefficient (ICC) values for automatic were 3.52% and 0.98; the values for manual were 3.44% and 0.97, respectively. For intersession reproducibility, the respective CVw and ICC values were 3.96% and 0.96. Good agreement was also found in 2 operators for both automatic and manual ACV measurements; nevertheless, poor agreement was found between RSC and AS-OCT (95% confidence interval (CI) for agreement of automatic RSC measurement versus AS-OCT were -96.3 to 72.8 microl and 95% CI for agreement of manual RSC measurement versus AS-OCT were between -41.7 to 10.1 microl).</p><p><b>CONCLUSIONS</b>Both RSC automatic and manual ACV measurements showed good repeatability and reproducibility, and showed comparable agreement between 2 independent operators, but poor agreement was found between RSC and AS-OCT.</p>