Analysis of Various Artifacts Produced by Spectral-Domain Optical Coherence Tomography Based on Macular Pathologies

PURPOSE: To report the frequency, severity and various types of artifacts associated with spectral-domain optical coherence tomography (SD-OCT) based on macular pathologies. METHODS: Data was collected retrospectively from 116 eyes of 116 subjects. SD-OCT (3D-1000, Topcon Corp., Japan) imaging was performed in 40 healthy eyes, 45 eyes with intraretinal pathology (IRP) and 31 eyes with subretinal pathology (SRP). The scan protocol was 12x6 mm radial scan. The frequency and types of artifacts were investigated in each scan and were analyzed based on macular disease. Additionally, the effect of artifacts on the measurement of macular thickness was studied. RESULTS: Errors occurred in 77 eyes (66.38%). Inner retinal boundary misidentification (IRBM) was the most common error (25.86%), with the frequencies of other types of artifacts being 10.34% for off-center fixation, 15.52% for degraded image and 8.6% for outer retinal boundary misidentification (ORBM). The overall error rate of SD-OCT in the retinal pathology group was much higher than that in the normal group. Macular thickness was underestimated in the IRP group because the outer retinal boundary of the IRP group tended to be misidentified toward the inner retina (p<0.01). CONCLUSIONS: SD-OCT can frequently cause various types of artifacts in patients with macular disease. When interpreting OCT images, the artifacts of SD-OCT should be considered in order to obtain accurate macular thickness and to prevent erroneous clinical decisions.

Ultrastructure of Rapidly Proliferating Preretinal Membrane of Very Extensive Ischemic Diabetic Retinopathy

PURPOSE: Using transmission electron microscopy (TEM), we studied the ultrastructures of rapidly proliferating preretinal membranes of young patients with very extensive ischemic proliferative diabetic retinopathy and diabetes with uncontrollable blood sugar level. METHODS: Nine cases of preretinal membranes were obtained from six eyes of five patients with rapidly progressed proliferative diabetic retinopathy (mean age, 35 years) during vitrectomy. We obtained each preretinal membrane bimanually as one single sheet membrane using intraocular scissors and forceps. Each tissue was fixed in 3% glutaraldehyde in the operating room. All specimens were prepared and studied using TEM. RESULTS: The preretinal membranes were composed of blood vessels and some interstitial cells. The blood vessels within the preretinal membranes varied in developmental stages, from the immature stage to the mature stage. The blood vessels were highly active, in that primitive cells showed a large nucleus and prominent chromatin clumping with abundant cytoplasm. Highly active fibroblast-like cells were also noted. CONCLUSIONS: We observed highly active angiogenesis in preretinal membranes, which rapidly proliferated in cases of severe retinal ischemia in young diabetes patients. This is the first report of such a finding, which may help to explain the poor prognosis of this disease modality.

Position-induced Cyclotorsion under Monocular Fixation

PURPOSE: To determine whether cyclotorsion occurs when a patient moves from the seating to supine position fixating with one eye. METHODS: The axis of astigmatism was measured with the handheld automated refractometer (Retinomax K-plus, Nikon, Japan) in 33 eyes having more than -1.0D cylinder in seated and supine positions under monocular fixation. RESULTS: There was a cyclotorsional deviation in 30 eyes (90.90%). Excyclotorsion was shown in 22 eyes (66.67%) and incyclotorsion in 8 (24.24%). Seventeen eyes (51.50%) had a torsional deviation less than 4 degrees, 5 eyes (15.15%) from 5 to 6 degrees, 7 eyes (21.21%) from 7 to 14 degrees and one eye greater than 15 degrees. CONCLUSIONS: Positionally induced cyclotorsion occurs under fixation with one eye simulating refractive surgery. Surgeons should therefore make an effort to align the wavefront measurement to the ablation onto the cornea.

Accuracy of Optic Disc Parameters Obtained by the Heidelberg Retina Tomograph in the Diagnosis of Glaucoma

PURPOSE: To determine which optic disc topographic parameters, obtained by the Heidelberg Retina Tomograph (HRT), are most useful to distinguish normal eyes from those with early to moderate glaucomatous visual field defects. METHODS: From each of 92 normal subjects and 154 patients with primary open-angle glaucoma one randomly selected eye was studied. The Humphrey perimeter, program C 30-2 visual fields, and 13 HRT parameters (software 2.01, includes rim to disc area ratio) were utilized. Because some of the optic disc parameters depend on the optic disc area, these parameters were corrected for the effect of disc area. The total glaucoma group was divided into three subgroups according to the visual field defects: early (mean deviation [MD] >-6 dB, 65 eyes), moderate (MD -6 to -12 dB, 49 eyes), and severe (MD <-12 dB, 40 eyes) glaucoma groups. RESULTS: In eyes with early glaucoma (MD = -3.43 +/- 1.60 dB), the sensitivity, specificity, accuracy, and areas under the receiver operating characteristic curve were, respectively: rim area (69%, 71%, 70%, 0.802), rim to disc area ratio (69%, 72%, 71%, 0.799), cup area (72%, 70%, 71%, 0.789) and cup to disc area ratio (69%, 70%, 69%, 0.790). In eyes with moderate glaucoma (MD = -8.75 +/- 1.88 dB), they were, respectively: rim area (78%, 86%, 83%, 0.872), rim to disc area ratio (76%, 86%, 82%, 0.869), cup area (76%, 87%, 83%, 0.864) and cup to disc area ratio (78%, 84%, 82%, 0.862). There was considerable overlap in HRT parameters between the normal and early glaucoma groups. CONCLUSIONS: The diagnostic value of single optic disc parameter had its limitations in the diagnosis of early stage glaucoma.

CD40 Activation Protects Dendritic Cells from Anticancer Drug-Induced Apoptosis

Dendritic cells (DCs) play a critical role in various immune responses involving CD4 T cells and have been used to generate anti-tumor immunity. Chemotherapy induces severe side effects including immunosuppression in patients with cancer. Although immunosuppression has been studied, the effects of anticancer drugs on DCs are not fully determined. In this study, we demonstrated that CD40 activation strongly protected DCs from 5-fluorouracil (5-FU) or mitomycin C-induced apoptosis. DC- specific surface markers, including CD11c and major histocompatibility complex (MHC) class II, were used for identifying DCs. CD 40 activation with anti-CD40 mAb significantly enhanced the viability of DCs treated with 5-FU or mitomycin C, assayed by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide). Fluorescence staining and analysis clearly confirmed the enhancing effect of anti-CD40 mAb on the viability of DCs, suggesting that CD40 activation may transduce critical signals for the viability of DCs. Annexin V staining assay showed that CD40 significantly protected DCs from 5-FU or mitomycin C-induced apoptosis. Taken together, this study shows that CD40 activation with anti-CD40 mAb has strong anti-apoptosis effect on DCs, suggesting that CD40 activation may overcome the immunosuppression, especially downregulation of number and function of DCs in chemotherapy- treated cancer patients.