How to change highcharts opacity on hover?

How can I change the opacity of a point on hover in Highcharts?

I am currently using the following, although it is very slow and laggy since I am running the points hex colour to convert it to RGBA. I am using a heatmap chart type.

plotOptions: {
    series: {
        point: {
            events: {
                mouseOver: function () {
                    var newColor = hexToRgb(this.color);
                    var formattedColor = "rgba(" + newColor.r + "," + newColor.g + "," + newColor.b + ",0.7)";
                    this.oldColor = this.color;
                    this.update({
                        color: formattedColor
                    });
                },
                mouseOut: function () {
                    this.update({
                        color: this.oldColor,
                    });
                }
            }
        }
    }
}

Is there any easier approach to this?