Anales de la RANM

247 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 Laura Morales An RANM. 2021;138(03): 246 - 255 ASSOCIATION BETWEEN VASCULAR AND STRUCTURAL PARAMETERS The recent development of Optical Coherence Tomography Angiography (OCTA) offers in vivo information of the retinal and choroidal microvas- culature in different regions (1). This non-invasive technique, using contrast imaging, allow us to obtain a quantitative assessment of the optic nerve head (ONH), peripapillary and macular microvas- cularity (2). It has been reported that glaucoma patients present a decrease of these vascular parameters (3). Previous studies reported that OCTA optic nerve head (ONH) vessel density measurements are associated with the severity of glaucoma and a strong correlation has been demonstrated between structural and vascular parameters. Indeed, lower ONH perfusion has also been related to a thinner macular ganglion cell complex and lower macular vessel density in adults with glaucoma (4,5). In normal children (6), OCTA parameters were reported in several articles. However poor informa- tion is available about the peripapillary and macular microvasculature in the literature in childhood glaucoma. Primary Congenital Glaucoma (PCG) is a rare disease but it is an important cause of vision loss in children. The diagnosis of PCG is based on clinical criteria. However, in the last years the introduc- tion of new devices such as optical coherence tomography (OCT), has proved to be useful for the management of paediatric glaucoma (7) as it provides objective retinal nerve fiber layer (RNFL) thickness and ganglion cell complex measure- ments (1). Recently, reduced peripapillary vascular parameters were reported in juvenile glaucoma using OCTA (8), however no information about changes on retinal micro vascularity were reported in PCG. This study was designed to determine the associa- tion of structural and vascular parameters using Cirrus OCT and OCTA, in patients diagnosed with primary congenital glaucoma. Study participant Observational and cross-sectional study. A total of 40 patients diagnosed with PCG were recruited. This study protocol adhered to the tenets of the Declaration of Helsinki and was approved by the Ethics Committee of the Hospital (a National Reference Centre for infant glaucoma). All participants aged 18 years or older, signed a written informed consent and it was obtained from the parents or legal guardians of partici- pants younger than this age (all children gave their verbal consent to participate in our study). 40 children diagnosed with PCG were recruited. Diagnostic criteria for PCG according to the Childhood Glaucoma Research Network classifi- cation are (9): IOP > 22 mmHg, clinical sings of glaucoma such as enlarged corneal diameter, Haab’s striae and glaucomatous appearance of the optic nerve head. Those included eyes had sufficient visual acuity for fixation, BCVA equal or higher than 0.05, good ocular media transparency and no other previous ocular surgery excepting glaucoma surgeries. The presence of nystagmus or leukoma was an exclusion criterion. All study participants underwent a comprehen- sive ophthalmologic examination by a single experienced examiner (LMF).The ophthalmic exam included: best-corrected visual acuity (BCVA) using decimal Snellen scale, and refractive state expressed as spherical equivalent (SE; cycloplegic refraction), intraocular pressure using the portable version of the Goldmann tonometer (Perkins,....), dilated fundus examination including cup-to-disc ratio determined by the same examiner (LMF), OCT and OCTA measurements using Cirrus OCT (HD-OCT 5000; Carl Zeiss Meditec, Inc., Dublin, CA, USA). When both eyes were eligible, only one eye was randomly selected (using a randomization web www. randomization.com ). OCTA measurements SD-OCT Cirrus ((Cirrus, HD-OCT 5000; Carl Zeiss Meditec, Inc., Dublin, CA, USA) was used to acquire macular and peripapillary scans. (11). The device´s software Angioplex TM (version 10.0, Carl Zeiss Meditec) includes the algorithm “optical microan- giography” (OMAG). This software with FDA approval, offers automatic measurements of vascular parameters in the superficial retinal plexus. All scans were performed using eye- tracking, by the same operator (LMF) with pupil dilation in a dark room on the same day as the other tests. Only good-quality scans with a signal strength index (SSI) >8 were included. Figure 1 shows the scan areas and the segmentations. Peripapillary scans (4.5x4.5mm) were performed for each patient, centred on the optic nerve. Automatically, Angioplex TM analyse the superfi- cial microvasculature located between an inner circle with a radius of 2mm and an outer circle with a 4.50 mm radius both centred on the ONH, divided on four quadrants: superior, inferior, temporal and nasal. Two peripapillary parame- ters were recorded: peripapillary perfusion density (pPD) and flux index (FI) for the global and quadrants (superior, temporal, inferior and nasal). pPD (the total area of perfused radial peripapillary capillary vasculature per unit area, %); and FI (a parameter between 0 and 1 representing the average decorrelation signal, no units) (figure 1.a.). INTRODUCTION MATERIAL AND METHODS