Topographical distribution of choroidal naevi in the ocular fundus

Abstract

Objective: To analyse the topographical distribution of choroidal naevi and to visualise their location in the ocular fundus. Methods: Data on the size and location of 210 choroidal naevi were converted into a database of two-dimensional retinal charts by means of computer-drawing software. The geometric centre of each lesion was entered into corresponding sectors of the retinal chart. The location of the naevi was computationally visualised by merging the fundus drawings and displaying the number of overlapping lesions on colour-coded contour maps. Results: Five naevi were located exactly between two fundus sectors, and were therefore excluded from the distribution analysis. Ten naevi (5%) were located anterior and 195 (95%) posterior to the equator. A total of 104 naevi (51%) were located in the temporal and 101 (49%) in the nasal hemisphere, and the distribution between the superior and inferior hemisphere was 104 (51%) and 101 (49%), respectively. The distribution did not differ significantly between genders, age groups, or between right and left eyes. More naevi with a diameter of >3 mm were located in the temporal hemisphere (P=0.0004) and anterior to the equator (P=0.006) compared with those with a diameter of ≤3 mm. A similar distribution was found for naevi with overlying drusen. Conclusions: Choroidal naevi are uniformly concentrated in the centre of the posterior pole without any significant nasotemporal or superoinferior asymmetry. However, large naevi occur significantly more often in the temporal hemisphere and more anteriorly compared with small lesions. © 2009 Macmillan Publishers Limited All rights reserved.