Differences in ocular dimensions between normal and dry eyes.

Assessment of ocular dimensions is essential for ophthalmic surgeons because these values must be determined before scheduling excimer laser refractive and cataract surgeries. Dry eye seems to affect central corneal thickness (CCT) values, but it is not clear if it affects anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and axial length values. Following on from this, we measured the CCT, ACD, LT, VCD and axial length of 64 healthy eyes (51.20%) and 61 dry eyes (48.80%). CCT was measured with scanning-slit corneal topography (Orbscan Topography System II, Orbscan, Inc., Salt Lake City, UT, USA) and ACD, LT, VCD and axial length with a 10-MHz A-mode ultrasound device (Compuscan; Storz, St. Louis, MO, USA). There were no significant differences in ACD (P=0.588), LT (P=0.739), VCD (P=0.568) and axial length (P=0.199) between normal and dry eyes. Nevertheless, the differences in CCT between normal (549+/-34 microm) and dry eyes (527+/-30 microm) were significant (P<0.001). In sum, it seems that only the CCT values are significantly lower in subjects with dry eye.