Improved visualization of macular hole lesions with laser biomicroscopy

We have developed instrumentation to improve the visualization of fine vitreoretinal structures at the macula during slit-lamp biomicroscopy. The instrument, mounted on a slit-lamp microscope, used a green helium-neon laser to deliver a narrow beam, 15 micron(s) in width and 2 mm in length. The intersection of the laser slit with the ocular structures was viewed at an angle, as in conventional slit-lamp biomicroscopy. The instrument was used to examine patients with idiopathic macular holes or cysts. The results indicated that the new illumination was superior due to the narrow width of the beam, the enhanced brightness, and the monochromacy in green, which reduced background scatter. These advantages allowed for visualization of fine retinal structures that are difficult to detect with conventional slit-lamp biomicroscopy. The findings in patients with idiopathic macular hole demonstrated that the operculum was located approximately 500 micron(s) anterior to the surrounding retina and moved minimally. This suggested that the operculum may be supported by partially detached posterior vitreous cortex, and that a macular hole is the result of tangential traction followed by axial traction caused by a contracted and detached cortical vitreous gel.