What is the standard distance between the segments in fused double segment multifocals?

The standard distance between the segments in fused double segment multifocals is typically 13-14mm. This measurement reflects the common practice in lens design, where the placement of the segments allows for effective visual transition between different focal areas, particularly for individuals who require both distance and near vision correction. The 13-14mm distance is chosen to provide adequate space for each segment while ensuring that the user can easily navigate between the segments for improved visual comfort and functionality. This distance is crucial in preventing any visual overlap or interruption, allowing for a smoother experience in daily activities that involve both near and far vision tasks.