ABSTRACT
Purpose: The purpose was to study the dimensions of the foveal avascular zone (FAZ) using Heidelberg Retinal Angiogram-2 (HRA-2; Heidelberg Engineering GmBH, Dossenheim, Germany). Materials and Methods: An observational study of the FAZ area and circumference was done with fundus fluorescein angiography (FFA) using HRA-2 in 31 normal individuals. The FAZ was studied using both contrast-adjusted and nonadjusted methods. Contrast adjustment was done to obtain better visualization of the finer capillaries around the fovea enabling more precise measurements of the FAZ in normal eyes. Results: The mean area of the FAZ calculated by the contrast-adjusted method was 0.2753 mm2 (±0.074) and the mean circumference was 2.22 mm (±0.048). By the conventional method, the area and circumference of the FAZ were 0.6241 mm2 (±0.177) and 3.23 mm (±0.454), respectively. Conclusion: The measurements of area and circumference of FAZ using contrast-adjusted methods were significantly smaller than the conventional method.
Subject(s)
Adult , Capillaries/diagnostic imaging , Female , Fluorescein Angiography , Fovea Centralis/anatomy & histology , Fovea Centralis/blood supply , Fundus Oculi , Humans , Male , Reference Values , Retinal Vessels/diagnostic imaging , Young AdultSubject(s)
Arteries/anatomy & histology , Skull/anatomy & histology , Frontal Sinus/anatomy & histology , Maxillary Sinus/anatomy & histology , Nasal Bone/anatomy & histology , Nasal Cavity/anatomy & histology , Nose/anatomy & histology , Orbit/anatomy & histology , Paranasal Sinuses/anatomy & histology , Turbinates/anatomy & histology , Skull Base/anatomy & histology , Ethmoid Bone/anatomy & histology , Fovea Centralis/anatomy & histology , Nasal Cavity/innervation , Nasal Cavity/surgery , Nasal Septum/anatomy & histology , Nasal Septum/innervation , Paranasal Sinuses/surgery , Sphenoid Sinus/anatomy & histologyABSTRACT
Foi investigada a existência de áster, uma estrutura radiada formada por axônios que transitam pela camada nuclear interna e presente na área central da retina de algumas espécies de aves foveadas, principalmente nas de atividade predatória. Na retina de outra aves, mamíferos e répteis estudados, a referida estrutura näo foi encontrada. O áster foi evidenciado através de técnicas histológicas variadas e de microscopia eletrônica de transmissäo