[Changes in the static visual field of patients with low and medium myopia]

Myopia is associated with many diverse changes in the structure and function of the eye. Determination of the visual field belongs to the diagnostic arsenal used for detection and monitoring of such alterations. It is well established that myopia is accompanied by changes in the kinetic visual field. Recently, static visual field examinations are gaining wider acceptance as they represent the most sensitive and reliable approach to early changes in myopia. However, only a few papers on static perimetry in myopia have been published and the results are conflicting. No publications have appeared in Polish medical press. Therefore, we decided to investigate which alterations occur in the static visual field of patients with myopia. We enrolled 32 men and 58 women (180 eyes) aged 19 to 34 (mean 23 years) and formed three groups (I-III) of 30 subjects each: (I) control (without any refractive anomaly); (II) low myopia (average refractive error -2.0 D sph. +/- SD of 1.0); and (III) medium myopia (average refractive error -5.6 Dsph +/- SD of 1.2). Myopia was defined as a refractive error of value < or = -0.5 D, with low myopia not exceeding 4.0 D, and medium myopia between -4 and -8 D. Inclusion criteria were: full visual acuity with/without correction, astigmatism < 0.75 D cyl., intraocular pressure < 21 mm Hg, and no eye pathology other than myopia. A full panel of ophthalmologic tests was carried out, including repeat static perimetry (central 30 degrees) with Medmont M600 perimeter. Appropriate lenses were used during the tests. Average Defect (AD), Pattern Defect (PD), Mean Sensitivity (MS), and Fluctuation (F) values were recorded. Static visual field was assessed with the repeat examination only. Spearman's rank correlation coefficient, Kendall's tau, Gamma and linear correlations were analyzed. P values of less than 0.05 were considered statistically significant. A reduction in AD among subjects with low (P < 0.03) and medium (P < 0.03) myopia was found. There were no significant alterations in PD (Tab. 1). Elevation of myopia leads to reduction in AD (P < 0.0003) (Fig. 1), reduction in MS (P < 0.004) (Fig. 2), as well as increase in F (P < 0.04) (Fig. 3).

Low and medium myopia may produce significant alterations in the visual field.