The volume of peripapillary vessels within the retinal nerve fibre layer: an optical coherence tomography angiography study of normal subjects

2017 ◽  
Vol 102 (5) ◽  
pp. 611-621 ◽  
Author(s):  
Davide Allegrini ◽  
Giovanni Montesano ◽  
Paolo Fogagnolo ◽  
Alfredo Pece ◽  
Roberta Riva ◽  
...  

Background/aimsTo investigate the contribution of vascular volume calculated by optical coherence tomography angiography (OCTA) to the measurement of peripapillary retinal nerve fibre layer (RNFL) thickness.MethodsWe used OCTA scans to build volumetric maps of the RNFL angiograms by thresholding the decorrelation images and summing the number of white pixels along the z-axis at each location. We used these maps to calculate the contribution of the vascular tissue to the RNFL thickness.ResultsWe analysed 51 eyes from 36 subjects. The mean RNFL volume calculated on the peripapillary region was 0.607±0.045 mm3 and the mean vessel volume was 0.217±0.035 mm3, with a mean vessel/total RNFL ratio of 35.627%±3.942%. When evaluated in the peripapillary circular section, the total contribution of the vascular tissue to the global RNFL thickness was 29.071%±3.945%. The superior and inferior sectors showed the highest percentage of vascular tissue within the RNFL circular profile (31.369% and 34.788% respectively).ConclusionsWe found that the vascular contribution to the RNFL thickness is 29.07±3.945%. This is much higher than what has been reported from calculations made on the structural OCT alone (13% reported by Hood et al and 11.3%±1.6% for the Cirrus OCT and 11.8%±1.4% for the Spectralis OCT reported by Patel et al). We conclude that evaluation of the vascular tissue contribution to the RNFL thickness with OCTA might be useful when performing precise quantification of the neuronal tissue.

2014 ◽  
Vol 6 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Madhu Thapa ◽  
Safal Khanal ◽  
Gulsan B Shrestha ◽  
Ananda K Sharma

Objective: To determine the normal values for peripapillary retinal nerve fibre layer thickness (RNFL) measured by spectral domain optical coherence tomography (SD- OCT) in a healthy Nepalese population and to compare the RNFL thicknesses between the genders and among the various age groups.Material and methods: One hundred and fifty six eyes of 156 healthy Nepalese subjects (66 males and 88 females) of various age groups were enrolled in this observational, cross-sectional, hospital-based study. The peripapillary RNFL of the randomly chosen eye of each subject was imaged with a high resolution SD-OCT (Spectralis HRA+OCT, Heidelberg Engineering). The RNFL thickness was measured around the optic nerve head using 16 automatically averaged, consecutive, circular B scans with a 3.4 mm diameter and compared between the genders and among the various age groups.Results: The mean age of the subjects was 38.94 ± 17.00 years (range - 14 to 76 years). The average peripapillary RNFL was found to be 102.64 ± 9.56 μm (95 % CI 97.01 - 101.93). The mean ± SD peripapillary RNFL measurements at the superior, nasal, inferior and temporal sectors in the study population were 129.51 ± 15.09 μm, 76.55 ± 12.02 μm, 134.53 ± 17.19 μm and 70.74 ± 15.53 μm respectively. The average RNFL thickness was 99.47 ± 10.18 μm in the male whereas it was 105.09 ± 8.31 μm in the female participants. The RNFL decreased by 2.26 μm per age per decade.  Conclusion: The Average RNFL thickness is 102.64 ± 9.56 μm in the Nepalese population. Gender and age related variation in the RNFL could serve as a useful guideline in the diagnosis of glaucoma in our population.DOI: http://dx.doi.org/10.3126/nepjoph.v6i2.11709Nepal J Ophthalmol 2014; 6(12): 131-139 


Author(s):  
Michael Reich ◽  
Jan Lübke ◽  
Lutz Joachimsen ◽  
Julia Stifter ◽  
Sebastian Küchlin ◽  
...  

Abstract Purpose To evaluate peripapillary retinal nerve fibre layer (RNFL) thickness measured by spectral domain optical coherence tomography (OCT) in patients with Stargardt disease (STGD). Methods A cross-sectional, monocentric, observational case-control study. Twenty patients (39 eyes) with ABCA4 mutations graded according to the Fishman STGD classification were included. RNFL measurement was performed using Heidelberg Spectralis SD-OCT. RNFL thickness in STGD patients was compared to age-matched data of healthy individuals provided by the device’s manufacturer. A manual readjustment of the optic disc-fovea angle was performed when needed. Results The mean age at first diagnosis of STGD was 22.9 years (range 9 to 50) and 39.1 years (range 18 to 74) at the time of examination. Thirty-nine percent of eyes (15 eyes) needed manual adjustment of the optic disc-fovea angle due to malfixation of the patients during OCT. The temporal quadrant corresponding to the macula showed a RNFL 16% thinner than controls (mean − 12 μm, 95%CI − 9 to −15 μm). However, global RNFL thickness did not differ from controls due to increased RNFL thickness of 12% in the nasal sectors. Duration and stage of STGD were not correlated to thinner RNFL. Conclusion STGD seems to be associated with thinner peripapillary RNFL in the sector of axons projecting to the degenerated macular area. It is yet unclear as to whether this results from anterograde transneuronal degeneration of direct injury to retinal ganglion cells.


2021 ◽  
Vol 9 (01) ◽  
pp. 62-71
Author(s):  
S. Mounica ◽  
◽  
B.V. Kranthi ◽  
M. Lakshmi Sarvani ◽  
◽  
...  

Purpose: The purpose of our study is to compare the average peripapillary retinal nerve fibre layer thickness by cirrus HD-Optical coherence tomography in emmetropic, axial myopic and axial hyperopic cases. Materials And Methods: Total of 120 subjects aged between 10 to 50 years were enrolled in this study, divided into 3 groups with 40 in each, namely group 1 - emmetropia, group 2- myopia >2.5 D and group 3-hypermetropia>2.5 D. In which, 58 (48.3%) were females and 62 (51.7%) were males. This study was done in the Department of Ophthalmology, Santhiram Medical College Hospital Nandyal,from October 2019 to March 2020. The average as well as quadratic assessment of peripapillary RNFL thickness by cirrus-HD optical coherence tomography and comparison among these 3 groups. Observation And Results: In our study, average peripapillary RNFL thickness between emmetropic, myopic and hyperopic groups was found to be statistically significant. The average peripapillary RNFL thickness was thickest in the hyperopic group (102.95 ± 5.629, n=40), followed by the emmetropic group (102.55 ± 5.505, n=40), and then the myopic group (83.38 ± 3.726, n=40) (all P<0.0001) . And in all four RNFL quadrants, myopic group showed thinning when compared to Emmetropic and hyperopic group (p<0.001).But hyperopic group showed thicker RNFL than emmetropic group only in temporal quadrants in right eye(p<0.001)and nasal and superior quadrants in left eye (p=0.017) Conclusion: In our study, average as well as in all the four quadrants peripapillary RNFL thickness shows highly significant results between emmetropia, myopia and hyperopia. When compared with emmetropia, RNFL thickness being thinnest in myopic group, and slightly thicker RNFL thickness in hyperopic group.


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