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Objective: To study how customizing the peripapillary scan diameter on the basis of optic nerve head (ONH) diameter affects retinal nerve fiber layer (RNFL) thickness measurements using Stratus optical coherence tomography (OCT)., Methods: Retinal nerve fiber layer was examined using 1 fixed-diameter circular scan (3.4 mm) and 2 customized-diameter scans (at 0.5 mm and 1 mm from the ONH edge) in 81 healthy subjects., Results: Using fixed-diameter scans, the mean RNFL thickness increased with larger ONH vertical diameters (r = 0.3425, P =.002), whereas using customized-diameter scans, negative correlations were detected (r = -0.3004 [P =.006] at 0.5 mm and r = -0.2369 [P =.03] at 1 mm from the ONH edge). The mean values obtained by customized-diameter scans showed lower standard deviations in most measurements, meaning a tendency toward lower interindividual variability., Conclusions: When RNFL thickness is measured at a constant distance from the ONH edge, larger discs exhibit a thinner RNFL. Hence, the correlation between large discs and thicker RNFLs observed using the standard fixed-diameter scan probably represents a technical artifact reflecting the shorter distance between the scan and the ONH edge. A new normative database, stratified not only on the basis of age but also on the basis of ONH size, is suggested.

Objective: To investigate the ability of optical coherence tomography (OCT) to assess changes in retinal nerve fiber layer (RNFL) thickness in optic disc edema., Methods: Prospective observational case series in a private eye clinic (Centro Salus). Twelve consecutive eyes (9 patients) with optic disc edema were analyzed, including 6 patients with anterior ischemic optic neuropathy, 1 patient with multiple sclerosis-associated papillitis, and 2 patients with bilateral papilledema. Peripapillary scans of the RNFL were obtained using Stratus OCT (software version 3.0; Carl Zeiss Meditec, Dublin, Calif). Repeated measurements were performed in 7 patients during a follow-up ranging from 8 to 30 weeks. The main outcome was RNFL thickness measurement., Results: Optical coherence tomography detected and quantified diffuse thickening of the RNFL. Compared with eyes in a control group of 75 healthy subjects, eyes with optic disc edema showed a significant increase in the mean RNFL thickness in all quadrants (temporal, P = .002; superior, P<.001; nasal, P<.001; and inferior, P<.001). In patients who were followed up, progressive thinning was observed as the disease evolved toward optic atrophy or clinical resolution., Conclusions: Optical coherence tomography can identify and measure RNFL edema. This ability of OCT may help elucidate pathophysiological mechanisms in optic disc edema and provide a valuable aid to clinicians.

Aim: To investigate whether retinal nerve fiber layer (RNFL) thickness, as measured by optical coherence tomography (OCT), is influenced by pupil size and cataract., Methods: RNFL thickness was measured by means of Stratus OCT (RNFL Thickness 3.4 acquisition protocol) in a group of consecutive patients undergoing phacoemulsification and intraocular lens implantation. Measurements were taken preoperatively without pupil dilation (PR1), preoperatively with pupil dilation (PR2), and 1 month postoperatively without pupil dilation., Results: Twenty-five eyes of 25 patients were enrolled in the study and underwent statistical analysis. Pupil dilation caused RNFL thickness measurements to increase slightly in PR2 compared with PR1; the difference showed to be statistically significant in the 360-degree average measurement (P=0.0456) and in the nasal quadrant (P=0.032), but not in the remaining quadrants. Postoperative measurements were higher than those of PR1 in all quadrants (temporal P=0.011; superior P=0.0098; nasal P<0.0001; inferior P=0.0081) and in 360 degrees average (P<0.0001), suggesting that the presence of cataract significantly influences RNFL thickness as measured by Stratus OCT. More advanced degrees of lens opacity were correlated to a higher decrease in RNFL thickness values (r=0.4071, P=0.0434)., Conclusions: While pupil size only marginally affects RNFL measurements performed by Stratus OCT, the presence and degree of cataract seem to have a significant impact. This effect should be taken in consideration when using this technology for the diagnosis of glaucoma and other neuro-ophthalmologic disorders possibly affecting the RNFL.

Background and Objective: To assess the ability of optical coherence tomography to visualize the inferior tear meniscus and measure its height., Patients and Methods: Twenty-seven eyes (27 patients) with aqueous tear deficiency were compared with 20 eyes (20 patients) with normal tear secretion (control group). After the instrument was focused on the ocular surface, a 4-mm long vertical scan, centered on the lower tear meniscus at corneal 6 o'clock hours, was obtained using optical coherence tomography. Tear meniscus height was measured by means of an external application., Results: Mean tear meniscus height was significantly lower (P < .0001) in patients with aqueous tear deficiency (mean +/- standard deviation: 0.13 +/- 0.07 mm) than in the control group (mean +/- standard deviation: 0.25 +/- 0.08 mm)., Conclusion: Optical coherence tomography can be used to noninvasively visualize the inferior tear meniscus. This method seems able to discriminate between patients with normal and dry eyes when measuring tear meniscus height.

Purpose: To assess the ability of standard optical coherence tomography to visualize filtering blebs after glaucoma surgery., Methods: A prospective interventional case series was conducted in a private practice. Twenty-nine eyes of 24 patients (21 with good, 2 with fair and 6 with poor intraocular pressure [IOP] control) were investigated. After the focus was manually adjusted on the conjunctiva, blebs were scanned perpendicularly to the limbus., Results: Hyporeflective fluid-filled spaces were detected in 19 out of the 21 eyes with good IOP. Within this group, blebs were classified into three different categories according to their optical coherence tomography pattern: type A (featuring a thick wall and a single large fluid-filled space), type B (featuring a thin wall and multiple large fluid-filled spaces) and type C (featuring multiple, irregular and flattened fluid-filled spaces). Fluid-filled spaces were not observed in three out of the six eyes with poor IOP control. Trabeculectomy without antimetabolites was associated with type A blebs (P = 0.015, Fisher's exact test), mitomycin-C trabeculectomy with type B blebs (P = 0.0025) and mitomycin-C phacotrabeculectomy with type C blebs (P = 0.0173)., Conclusions: Although it was not developed to evaluate the anterior segment of the eye, standard optical coherence tomography can visualize filtering blebs and reveal interesting details of their morphology. Clinicians using optical coherence tomography to diagnose glaucoma can take advantage of this ability of the instrument to obtain more information about their patients in the postoperative course of trabeculectomy and phacotrabeculectomy.

Purpose: To study retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (StratusOCT) in patients with Leber's hereditary optic neuropathy (LHON)., Design: Cross-sectional study., Participants And/or Controls: Thirty-eight patients with LHON were analyzed and compared with an age-matched control group of 75 patients. Patients with LHON were classified as having early LHON (E-LHON, n = 8) when the duration of the disease was shorter than 6 months and atrophic LHON (A-LHON, n = 30) when the duration was longer than 6 months., Methods: The fast RNFL thickness (3.4) scan acquisition protocol was used., Main Outcome Measure: Retinal nerve fiber layer thickness as measured by StratusOCT., Results: Compared with the control group, eyes with E-LHON showed a thicker RNFL in the 360 degrees average measurement (P<0.01) and in the superior (P<0.01), nasal (P<0.05), and inferior quadrants (P<0.05); no significant changes were detected in the temporal quadrant. Eyes with A-LHON revealed a thinner RNFL in all measurements (P<0.001); the fibers of the nasal quadrant showed the lowest amount of reduction (38% vs. 42%-49.8% in the other quadrants). In cases with A-LHON and visual recovery, RNFL was significantly thicker in all measurements (P<0.001), except the temporal quadrant, with respect to A-LHON without visual recovery., Conclusions: On the basis of OCT data, the RNFL is thickened in E-LHON and severely thinned in A-LHON. RNFL is likely to be partially preserved in A-LHON with visual recovery. The temporal fibers (papillomacular bundle) are the first and most severely affected; the nasal fibers seem to be partially spared in the late stage of the disease.