Measurement of the posterior precortical vitreous pocket in fellow eyes with posterior vitreous detachment and macular holes.

摘要

PURPOSE: To evaluate the premacular vitreous zone of liquefaction (the posterior precortical vitreous pocket [PPVP]) using contact B-scan ultrasonography and to compare the size of the observed PPVP in fellow eyes with posterior vitreous detachment (PVD) as compared with fellow eyes with macular holes. METHODS: Patients with a fellow eye having a PVD or macular hole but not having a PVD in the examined eye were evaluated with contact B-scan ultrasonography to measure the PPVP. RESULTS: The mean age +/- SD of the 19 patients was 63.9 +/- 7.8 years. There were 13 patients in the PVD group and 6 in the macular hole group. All patients in the macular hole group had a vitreous detachment in the macular region of the eye with the macular hole. There was no difference in the mean age (P = 0.44, independent samples t test) or mean refractive error (P = 0.56) of the two groups. The PPVP was seen to be round to ovoid in shape with a mean anteroposterior dimension of 8.4 mm and a mean horizontal dimension of 9.2 mm for all patients. The mean anteroposterior measurement was 7.6 mm in the PVD group versus 10.3 mm in the macular hole group, a difference that was significant (P = 0.004, independent samples t test). In a similar manner, the mean horizontal dimension was 8.2 mm in the PVD group and 11.1 mm in the macular hole group, a difference that was significant (P = 0.031). CONCLUSIONS: The PPVP was larger in fellow eyes in the macular hole group. The larger PPVP would be expected to cause a greater degree of force concentration and a more pronounced shifting of the direction of the force vector for anteroposterior tensile stress to one being more tangential to the surface of the retina in these patients.