Análise descritiva do disco óptico e da camada de fibras nervosas da retina utilizando tomografia de coerência óptica em olhos portadores de megalopapilas e em olhos normais

Abstract

TITLE: DESCRIPTIVE ANALYSIS OF OPTIC DISC AND RETINAL NERVE FIBER LAYER USING OPTICAL COHERENCE TOMOGRAPHY IN MEGALOPAPILLA EYES AND NORMAL EYES OBJECTIVES: To evaluate the optic disc and retinal nerve fiber layer (RNFL) thickness in megalopapilla cases by confocal scanning laser ophthalmoscopy (CSLO) and Time-domain optical coherence tomography (TD-OCT). To assess the importance of these measurements in diagnosing megalopapilla. To evaluate the eyetracking-based follow-up (EBF) function in the reproducibility of the peripapillary retinal nerve fiber layer (RNFL) thickness measurements in healthy subjects obtained with Fourier-domain optical coherence tomography (FD-OCT). MATERIAL AND METHODS: This research consists of two descriptive studies. In the first one 59 eyes (30 patients) diagnosed as megalopapilla were submitted to CSLO examinations with the Heidelberg Retina Tomograph (HRTII, Heidelberg Engineering). Thickness of the RNFL around the optic disc was measured with StratusTM OCT, version 4.0.1 (Stratus OCT; Carl Zeiss Meditec). A descriptive analysis was made using SPSS (version 12.0; SPSS Inc., Chicago, IL) statistical software. In the second study, 30 eyes were imaged on FD-OCT device at the same visit by two examiners. Circular scans centered on the optic disc, in high-speed mode with the automatic real time mean module, were used. After acquisition of the first scan (baseline), two additional peripapillary scans were obtained by each examiner, without and with the EBF function activated. Intraclass correlation coefficient (ICC) and repeatability coefficient (RC) were calculated. RESULTS: The mean global optic disc area (±SD) for all eyes with megalopapilla was 3.28 (± 0.53) mm² and was not statistically different among races (P 0.159) or sex (P 0.108). The average RNFL thickness was 102.50 (±12.68) m. In normal eyes, mean (±SD) global RNFL thickness was 105.1 (±9.5) m on HS mode and 105.4 (±9.6) m on HR mode. Interobserver analysis for global RNFL thickness revealed an intraclass correlation coefficient (ICC) 0.96 for all but the HR mode without the use of EBF function (ICC=0.73). Intraobserver analysis for global RNFL thickness revealed an ICC > 0.98 for all but the HR mode without the use of EBF function (ICC=0.86). The interobserver and intraobserver analysis revealed the lowest ICC values for the temporal region on both HS and HR modes. Higher ICC values were obtained with the HS mode and when the EBF function was activated, especially using the HR mode. CONCLUSIONS: Megalopapilla is a congenital anomaly of the optic nerve which features disc area above the normal range values, as well as an increase in cup-to-disc ratio, considered by these features, important differential diagnosis of glaucomatous neuropathy. However, it has RNFL thickness within normal limits as measured by TD-OCT. In a sample of normal eyes, assessed by FD-OCT, the EBF function had no significant influence in the reproducibility of the global peripapillary RNFL thickness measurements in healthy subjects on HS mode. However, the reproducibility of global peripapillary RNFL thickness measurements on HR mode, and the peripapillary RNFL thickness measurements in the temporal and temporal superior regions, in HS and HR modes, were greater with the EBF function.