We read with interest the recent article by Ivastinovic and associates titled “Evolution of early changes at the vitreoretinal interface after cataract surgery determined by optical coherence tomography and ultrasonography.” The authors are to be commended for reporting the results of a prospective consecutive study to evaluate the onset of posterior vitreous detachment (PVD), including early changes at the vitreoretinal interface after uneventful phacoemulsification in nonmyopic eyes using optical coherence tomography (OCT) and ultrasound.
Dr Ivastinovic and associates found that some degree of PVD was noted in 59.2% of eyes 1 month after surgery and in 71.4% of eyes 3 months after surgery. In patients older than 70 years some degree of PVD was diagnosed in 92.3% compared with 47.8% in patients younger than 70 years. They 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. Age over 70 years was associated with an increased onset of postoperative PVD.”
Our studies support the findings of Dr Ivastinovic and associates. We have previously reported a study entitled “Fluid dynamics in the anterior chamber: Its possible role in pseudophakic retinal detachment after uneventful phacoemulsification” (Yepez JB, unpublished data, May 2010). The purpose of our report was to evaluate the possible passage of fluid from the anterior chamber to the vitreous cavity through the zonules during an uneventful phacoemulsification, and its possible role in the development of pseudophakic retinal detachment. Two tests were used to demonstrate the passage of fluid through the zonules (previously shown clinically during vitrectomy by Ikeda and associates and Yepez and associates ) during an uneventful phacoemulsification: 1) magnetic resonance imaging (MRI) was used to test 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. We found with MRI 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 anterior vitreous detachment (AVD) of various degrees in all 10 patients who underwent phacoemulsification.
According to our preliminary experimental and clinical results, we concluded that during an uneventful phacoemulsification an important 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; and an 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. Early PVD after phacoemulsification may be associated with the development of retinal tears and retinal detachment.