Session Title: Imaging IV
Session Date/Time: Sunday 20/09/2015 | 11:00-13:00
Paper Time: 12:20
First Author: : L.BobergAns DENMARK
Co Author(s): : M. Larsen P. Mitchell B. Gopinath J. Wang I. Munch
PURPOSE:To study the distribution of Gunn dots on the vitreoretinal interface as seen on fundus photographs in a large sample of adolescent children.
Westmead Millinnium Institute, Centre for Vision Research, Sydney, Australia.
Red-free, digital fundus photography (four-field 50° non-stereoscopic) was performed in 2286 children aged 11 to14 years who completed a detailed eye examination in the 2004-2005 school year. Gunn dots were manually marked and counted within an ETDRS grid centered on the optic disc and assessed semi-quantitatively outside the grid. Associations with ocular and systemic parameters previously collected in the Sydney Myopia Study were investigated including the average retinal nerve fiber layer thickness (RNFL) assessed by time-domain optical coherence tomography.
One or more Gunn dots were seen in at least one eye in 82.5% of the 2286 children (mean age=12.7 years, 50.6% boys). The prevalence was comparable between boys and girls. The median number of Gunn dots per eye (mean of both eyes) was 46 (range 0 to 482). The majority of dots were observed inferior of the disc (49.3 %) and superior of the disc (45.6%) with only 0.4% of dots being found temporal of to the disc and 4.6% nasal of the disc. Gunn dots were associated with darker iris color, with an odds ratio (OR) of 2.99 (CI95: 1.81-4.94), P<0.0001 when comparing children with dark brown eyes with children with blue eyes in an analysis adjusted for age, sex, RNFL, refraction, ethnicity and axial length. In the same analysis, a thinner average RNFL reduced the odds of having Gunn dots to an OR of 0.68 (CI95: 0.49-0-93), P=0.0161 when comparing children in the 1st quartile of RNFL thickness (60µm-97µm) with children in the 4th quartile of RNFL thickness (111µm-163µm). Gender, age, refraction and axial length were not associated with the presence of Gunn dots.
Gunn dots were visible on fundus photographs in the majority of 11-14 year old children and were most prevalent inferiorly and superiorly of the optic disc. The presence of Gunn dots (≥ 1) in either eye was associated with darker iris pigmentation and a thicker RNFL. The clinical significance of Gunn dots, which are believed to represent the footplates of Müller cells, remains to be elucidated.