Automated static perimetry in myopes with peripapillary crescents--Part II.

Central visual fields were investigated by automated static perimetry, using programs 30-2 and 30-1 of the Humphrey Field Analyzer (HFA), in a group of healthy myopic individuals with peripapillary crescents and tigroid fundus changes only. Results were compared with 'non-myopic' and 'myopic subjects without crescents' control groups. The sample comprised 122 young, healthy volunteers between the ages of 18.5 and 35.4 years, free from any ocular or systemic disease, with refractive errors ranging from +4.00 to -25.75 D. Linear regression results are presented and may be useful in predicting the global indices mean deviation (MD) and mean sensitivity (MS), given either the axial length or ocular refraction, for medium and high myopes. Analysis of the HFA printouts revealed significantly depressed locations in all subject groups. However, locations identified at the 2, 1 and 0.5% probability levels were observed more frequently and more commonly in the myopes with peripapillary crescents than in the control groups. In this non-glaucomatous sample, four myopes had a borderline glaucoma hemifield test and two fell outside normal limits of this test. The superior hemifield, particularly the upper temporal quadrant, appeared to be most affected. Enlargement of the blind spot occurred in some subjects. Several possible explanations are suggested for the visual field sensitivity reduction in myopia.