Subretinal Surgery Ab Externo: A Novel Approach to Access the Subretinal Space Without the Need for Retinotomy.

A standard 23-gauge or 25-gauge valved trocar is positioned externally next to the sclera at an area corresponding to the most elevated retina. During internal visualization, the trocar is advanced at an angle of 15°, penetrating the sclera and the choroid, and entering the subretinal space (Figure 2). Once it has been visually confirmed that the cannula entered the subretinal space, the trocar is removed and the cannula remains in the subretinal space. Controlled access of the subretinal space has now been achieved. There will be no drainage of the subretinal fluid because the valve of the cannula prohibits this.