Azusa Kusuhara

Comparison of Pentacam Scheimpflug Camera with Ultrasound Pachymetry and Noncontact Specular Microscopy in Measuring Central Corneal Thickness

Purpose: Although central corneal thickness (CCT) can be measured by several methods, interchangeability of different modalities has not been fully investigated. CCT is known to correlate with intraocular pressure (IOP). The aim of this study was to evaluate the agreement of Pentacam Scheimpflug system with noncontact specular microscopy (NCSM) and ultrasound (US) pachymetry in measuring CCT and the relation between IOP taken with Goldmann applanation tonometer (GAT) and the CCT measured with these three methods. Methods: The right eyes of 135 enrolled persons without antiglaucoma drug use (100 females and 35 males), who comprised 32 patients with primary open-angle glaucoma, 14 with ocular hypertension, 45 with primary angle-closure glaucoma, and 44 controls, were studied. Intermethod comparison of CCT was made by the 95% limits of agreement analysis according to Bland and Altman. Linear regression analysis was used to assess the relationship between IOP and CCT taken with each modality. Results: The mean CCT (±SD) taken with Scheimpflug, US, and NCSM was 559.49 ± 38.44 μ m, 553.01 ± 39.33 μ m, and 552.04 ± 42.95 μ m, respectively. The average values of CCT taken with the three instruments were not significantly different (one-factor ANOVA; p = 0.26), although the marginal mean difference between Scheimpflug and US or NCSM was statistically significant (paired t test; p = 0.0009 and 0.005, respectively). The 95% limits of agreement were 6.47 ± 43.21 μm between Scheimpflug and US, 7.45 ± 58.86 μ m between Scheimpflug and NCSM, and 0.98 ± 51.69 μ m between US and NCSM. There was a positive association between IOP and CCT measured with US or NCSM, whereas there was no correlation between IOP and CCT measured with Scheimpflug. Conclusions: Although CCT values measured with Scheimpflug, US, and NCSM are closely similar, clinicians should keep in mind that these methods are not simply interchangeable.

Retinal Nerve Fiber Layer Thickness in Optic Tract Syndrome

BackgroundOptic tract syndrome (OTS) is characterized by incongruous homonymous hemianopia and a perpendicular pattern of bilateral optic atrophy due to the optic tract lesion. However, loss of retinal nerve fiber layer thickness (RNFLT) associated with OTS has not been quantitatively assessed.CaseA 20-year-old woman with blunt head trauma showed normal visual acuity, color vision, ocular motility, and intraocular pressure. Because of a relative afferent pupillary defect in her left eye and left-sided homonymous hemianopia, we suspected right-sided optic tract damage, although magnetic resonance imaging detected no intracranial lesion.ObservationsUsing optical coherence tomography (OCT), the RNFLT of this case was measured at 31 months after the trauma and compared with age-matched normal controls (n = 41). Nasal, temporal, superior, and inferior quadrant RNFLT was reduced by 22%, 21%, 5%, and 46% in the right eye and 76%, 64%, 25%, and 27% in the left eye, respectively. The reduction was > 3 × the standard deviation of the normal mean values in the nasal and temporal quadrants of the left eye and in the inferior quadrant of the right eye.ConclusionsOCT can determine the RNFLT reduction corresponding to the characteristic patterns of optic atrophy of OTS. Jpn J Ophthalmol 2005;49:294–296

Quantification of retinal nerve fiber layer thickness reduction associated with a relative afferent pupillary defect in asymmetric glaucoma

Aim: The relative afferent pupillary defect (RAPD) is an important clinical sign of asymmetrical retinal ganglion cell and axonal damage. Although glaucoma essentially affects bilateral eyes, a subset of patients manifests asymmetrical glaucomatous optic neuropathy (GON), which exhibits an RPAD in the more advanced eyes. However, the degree to which axonal loss occurs before an RAPD is clinically detectable has not been substantiated. The purpose of this study is to assess the relationship between the depth of a clinically detectable RAPD and the reduction ratio of retinal nerve fiber layer (RNFL) thickness in the more advanced eyes relative to that in the contralateral less advanced eyes of patients with asymmetrical GON. Methods: Enrolled were 29 consecutive glaucoma patients with the clinically detectable RAPD. An RAPD was quantified by placing log-scaled neutral density filters over the less advanced eyes while performing the swinging flashlight test. Average RNFL thickness was determined using the Fast RNFL thickness programme of optical coherence tomography 3000. Correlation coefficient and Linear regression analyses were used in assessing the relationship between the RAPD and the ratio of RNFL thickness in the more advanced eyes relative to that in the less advanced. Results: RAPD ranged from 0.6 to 2.4 log units. The log-scaled RAPD had a statistically significantly inversed correlation with the average RNFL thickness ratio (rs = −0.729, p<0.0001). Linear regression analysis found an equation that the average RNFL thickness ratio in the more affected eyes relative to that in the less advanced (%)  = (0.827−0.169×RAPD (log units))×100 (R2 = 0.557, p<0.0001). Conclusions: When an RAPD is clinically detected, the RNFL thickness in the more advanced eyes was in average reduced to about 73% of that in the less advanced.