Abstract
Purpose :
The role of Optical Coherence Tomography (OCT) macula scans in glaucoma has been extensively investigated. However, to date, despite the establishment of state-of-the-art retinal imaging technology, only subjective and qualitative analyses can be performed for macula scans in glaucoma.
In this study we propose a novel method to objectively assess glaucoma progression based on the Longitudinal Analysis of the Poster Pole (LaPo).
Methods :
40 eyes from 20 patients attending the Glaucoma clinic at the Western Eye Hospital in London were retrospectively assessed over a period of 3 years with visits interval of 4-6 months. Conventional Posterior Pole (PPole) scanning protocol and Peripapillary RNFL protocol were acquired using Heidelberg Spectralis SD-OCT. Longitudinal measurements of Total Retina (TR) , Retinal Nerve Fiber Layer (RNFL) and Ganglion Cells Layer (GCL) thickness were performed from the 8X8 grid (64 super pixels) centered on the foveal pit after automated layer segmentation. Thickness gradients and Lineal regression analyses were calculated for all 64 super pixels in each eye over time using “R” software (https://www.R-project.org). All data are expressed as mean ± SD. P<0.05 was considered as significant.
Results :
Linear regression analysis of individual super pixel showed that LaPo can detect progression significantly earlier that RNFL peripapillary scan in 90.4% (whole retina: 3.8 ±0.8 visits vs 6 ±0.9 visits, p<0.0001), 96% (RNFL: 3.7 ±0.6 visits vs 5.6 ±0.6 visits, p<0.0001) and 83% (GCL: 4 ±0.8 visits vs 5.6 ±0.7 visits, p<0.01) of eyes. Topographic gradient analysis of individual super pixel showed also consistent supero-temporal thinning of the TR, RNFL and GCL beyond the peripapillary circle scan in 78% of progressing eyes.
Conclusions :
In this study we have shown a novel method for objectively quantify glaucoma progression using the Heidelberg Spectralis PPole scanning protocol. In agreement with the literature, we suggest that macular thickness changes are a potential biomarker for glaucoma diagnosis and progression. Indeed, our methodology could contribute to the early identification of progressing patients and may also have a role in glaucoma surveillance schemes. Further studies are needed to optimize this methodology for glaucoma care.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.