Effects of pseudophakic lens capsule opacification on optical coherence tomography of the macula

To report observations on the influence of posterior lens capsule opacification on optical coherence tomographic imaging quality and measurements of macular thickness.

The retrospective study included 13 eyes in 12 patients of which 2 eyes had a healthy macula and 11 eyes had maculopathy. In all eyes posterior lens capsule fibrosis was present. A clinical examination including biomicroscopy of the macula and an in-vivo macular optical coherence tomography (OCT) before and after YAG-laser membranotomy had been performed.

Foveal retinal thickness before and after membranotomy were highly correlated (R = 0.98), and no systematic difference was found between values obtained before vs. after membranotomy (mean thickness 318.7 +/- 92.7 microm vs. 322.2 +/- 97.4 microm; p = 0.221). The signal-to-noise ratio increased in 11 out of 13 eyes after membranotomy (mean signal-to-noise ratio before 47.1 +/- 6.6 dB vs. 52.6 +/- 4.0 dB after; p = 0.004, the change ranging from -1.5 dB to 17 dB).

The qualitative effect of the posterior lens capsule opacification on the OCT-scan consists primarily of a loss of signal and consequently of intraretinal detail, whereas total foveal retinal thickness seems to be reliably assessed even when posterior lens capsule opacification interfering with the biomicroscopic evaluation of retinal edema are present. YAG-laser membranotomy results in a measurable improvement in the OCT signal-to-noise ratio, but OCT seems to yield reliable measurements of foveal retinal thickness before treatment. Consequently the OCT seems to reliably diagnose a macular thickening although not the type of this until after removal of the posterior lens capsule opacification.