JAN 30, 2013
The authors of this correspondence say their research supports the findings of a study that identified some degree of posterior vitreous detachment (PVD) in 59.2 percent of eyes one month after cataract surgery and 71.4 percent after three months. Their preliminary and unpublished experimental and clinical results found that during uneventful phacoemulsification, a noteworthy amount of fluid passes through the zonules from the anterior chamber to the vitreous cavity, and this fluid could cause a hydrodissection of the anterior hyaloid. An anterior vitreous detachment (AVD) occurs with hydratation of the vitreous that, along with ocular movements, leads to the development of anatomic and biochemical changes including liquefaction, which may help explain the mechanism of PVD. They conclude that early PVD after phacoemulsification may be associated with the development of retinal tears and detachment.
The published study ran in the April 2012 issue of the American Journal of Ophthalmology and prospectively examined early changes at the vitreoretinal interface using optical coherence tomography (OCT) and ultrasound after uneventful phacoemulsification in consecutive patients. The study's authors concluded that, "OCT yields insights into the evolution of early-stage PVDs following uneventful phacoemulsification surgery. OCT both identifies more cases of vitreoretinal separation than other detection methods and discloses the dynamics of the vitreoretinal interface changes in the postoperative course."
The authors of the correspondence have conducted unpublished research to evaluate the possible passage of fluid from the anterior chamber to the vitreous cavity through the zonules during uneventful phacoemulsification and its possible role in the development of pseudophakic retinal detachment. They conducted two tests: 1) magnetic resonance imaging (MRI) was used to examine permeability of the zonular diaphragm in 10 pig eyes that underwent gadolinium-assisted phacoemulsification; and 2) ultrasound biomicroscopy (UBM) was performed in 10 patients before and after phacoemulsification to test the effect of the fluid on the zonular-anterior hyaloidal diaphragm.
MRI showed that gadolinium passed through the zonules, and the amount of gadolinium passing through the zonules depended on the height of the bottle during phacoemulsification. In addition, UBM findings demonstrated AVD of various degrees in all 10 patients who underwent phacoemulsification.