Tangential vitreous traction: a possible mechanism of development of cystoid macular edema in retinitis pigmentosa

Abstract

We report the possible mechanism of development of cystoid macular edema (CME) in retinitis pigmentosa (RP) in the case of a 68-year-old woman with RP and CME in the right eye and resolving CME in the left eye. Spectral domain optical coherence tomography showed CME and posterior vitreoschisis in the nasal quadrant of the fundus without a posterior vitreous detachment (PVD). This vitreous pathology suggested bilateral thickening and shrinkage of the posterior vitreous cortex. In the right eye, CME was evident with no vitreofoveal separation. However, in the left eye, minimal change was seen in the CME associated with a focal shallow PVD over the fovea. The best-corrected visual acuity (BCVA) in the left eye increased to 0.3 from 0.15 7 years after the first visit. Tangential vitreous traction on the macula may have caused the CME in the right eye. The shallow PVD over the fovea might have released the tangential vitreous traction from the fovea, induced spontaneous resolution of the CME, and improved the BCVA in the left eye.

Keywords: cystoid macular edema; optical coherence tomography; posterior vitreoschisis; posterior vitreous detachment; retinitis pigmentosa.

Figure 1

Fundus appearance of the right A) and left B) eyes. The bone spicule deposits are clustered just anterior to the posterior pole. The cystoid macular edema is unremarkable in this photograph of both eyes. The white line indicates the optical coherence tomography scan line in Figure 4.

Figure 2

The electroretinogram (ERG) of the current case compared with that of a normal eye. The patient has no ERG responses, including flash, cone, rod, and 30-Hz flicker.

Figure 3

Goldmann kinetic perimetry indicates the marked constriction of the V-4 isopter and the inferior peripheral remaining visual field.

Figure 4

Spectral domain optical coherence tomography images of the right A) and left B) eyes. In the right eye, cystoid macular edema (CME) at the fovea and posterior vitreoschisis (arrow) in the nasal quadrant is seen without a posterior vitreous detachment (PVD). In the left eye, minimal CME at the fovea with a focal PVD (arrowhead) and posterior vitreoschisis (arrow) in the nasal quadrant are seen.