We recently reported about the prevalence of posterior vitreous detachment (PVD) after cataract surgery. The study showed that uneventful phacoemulsification in eyes with complete vitreoretinal attachment induces some degree of PVD in 71.4% within 3 months after the surgery. The status of the posterior vitreous cortex (PVC) was evaluated with both optical coherence tomography (OCT) and ultrasound. PVD was classified further in stages. Accordingly, stage 1 was defined as perifoveal detachment of PVC in 1 to 3 quadrants of the macula; stage 2 was defined as PVC detachment in all quadrants with persisting attachment to the fovea and optic nerve disc; stage 3 was defined as complete detachment of PVC from the macula and optic nerve disc, but remaining attachment to the midperiphery of the retina; and stage 4 was defined as complete vitreoretinal detachment from the posterior pole.
We subsequently evaluated the prevalence of PVD 1 year after phacoemulsification in the same cohort of patients we initially enrolled in the previous study. This was a prospective study approved by the Ethics Committee of the Medical University Graz. Informed consent was obtained from all participants before inclusion in the study. Of 49 patients enrolled in the initial study, 35 patients agreed to participate in the 1-year evaluation. Their average age was 71.9 ± 8.7 years; 18 of them were female and 17 were male. We observed some degree of PVD in all eyes. PVD stage 1 was detected in 5 eyes (14.3%), stage 2 was detected in 7 eyes (20%), stage 3 was detected in 4 eyes (11.4%), and stage 4 was detected in 19 eyes (54.3%). In comparison, 3 months after surgery, stage 1 was observed in 12.2% of eyes, stage 2 was detected in 20.4% of eyes, stage 3 was detected in 6.1% of eyes, and stage 4 was detected in 32.6% of eyes. The progression of PVD toward a higher stage throughout the 1-year follow-up was significant ( P = .005, Cochran-Q test). The distance between the PVC and the inner retina was evaluated with OCT and averaged 87.7 ± 29.9 μm in stage 1, 232 ± 62.5 μm in stage 2, and 558.2 ± 83.3 μm in stage 3. PVD stage 4 could be detected only with ultrasound; the distance was not measured.
Our observation substantially differs from a previous report showing a postoperative PVD rate of 58.6% within 1 year after uneventful phacoemulsification. In that study, PVD was assessed biomicroscopically and with ultrasound according to standards at that time. OCT, however, was shown to be a valuable tool for detection of very early PVD stages. In our study, PVD was evaluated with ultrasound and complementary OCT. Hence, the difference in postoperative PVD rates of 41.6% among the studies is attributable to the PVD assessment method. In detail, a considerable proportion of 12 eyes (34.3%) had PVD stage 1 or 2. According to our experience, these stages would have remained undetected without OCT. In summary, using complementary OCT for PVD assessment reveals substantially higher PVD rates than previously reported.