Tip Line Research Articles

Fault on–off versus coseismic fluids reaction

The fault activation (fault on) interrupts the enduring fault locking (fault off) and marks the end of a seismic cycle in which the brittle-ductile transition (BDT) acts as a sort of switch. We suggest that the fluid flow rates differ during the different periods of the seismic cycle (interseismic, pre-seismic, coseismic and post-seismic) and in particular as a function of the tectonic style. Regional examples indicate that tectonic-related fluids anomalies depend on the stage of the tectonic cycle and the tectonic style. Although it is difficult to model an increasing permeability with depth and several BDT transitions plus independent acquicludes may occur in the crust, we devised the simplest numerical model of a fault constantly shearing in the ductile deeper crust while being locked in the brittle shallow layer, with variable homogeneous permeabilities. The results indicate different behaviors in the three main tectonic settings. In tensional tectonics, a stretched band antithetic to the normal fault forms above the BDT during the interseismic period. Fractures close and fluids are expelled during the coseismic stage. The mechanism reverses in compressional tectonics. During the interseismic stage, an over-compressed band forms above the BDT. The band dilates while rebounding in the coseismic stage and attracts fluids locally. At the tip lines along strike-slip faults, two couples of subvertical bands show different behavior, one in dilation/compression and one in compression/dilation. This deformation pattern inverts during the coseismic stage. Sometimes a pre-seismic stage in which fluids start moving may be observed and could potentially become a precursor.

Pathophysiology of macular hole and diagnostic tools

AbstractPurpose Our understanding of the pathophysiology of macular hole development has evolved as the diagnostic tools at our disposal have become increasingly sophisticated. Methods Critical review of current published literature regarding pathogenesis of macular hole formation and an appraisal of modern imaging tools such as SD‐OCT, SLO‐microperimetry in diagnosis and prognostication. Results Perifoveal PVD with vitreomacular adhesion and vitreoschisis allow cortical vitreous to remain on the retinal surface and act as a scaffold for cell proliferation.The presence of a contiguous photoreceptor inner/outer segment (IS/OS) line indicating well‐restored photoreceptor cells is increasingly becoming a measure of functional success. Combined SD‐OCT and SLO microperimetry studies suspect that ILM peeling may reduce retinal sensitivity. Conclusions Macular hole size seems to be among the best prognostic factors available, however several computerised algorithms as well as the presence or absence of an intact IS/OS layer may correlate with visual outcome. Changes in retinal morphology such as the length of the foveal cone outer segment tips line defect may prognosticate visual acuity after macular hole closure.

3D seismic analysis of the structure and evolution of a salt-influenced normal fault zone: A test of competing fault growth models

In this paper we determine the structure and evolution of a normal fault system by applying qualitative and quantitative fault analysis techniques to a 3D seismic reflection dataset from the Suez Rift, Egypt. Our analysis indicates that the October Fault Zone is composed of two fault systems that are locally decoupled across a salt-bearing interval of Late Miocene (Messinian) age. The sub-salt system offsets pre-rift crystalline basement, and was active during the Late Oligocene-early Middle Miocene. It is composed of four, planar, NW–SE-striking segments that are hard- linked by N–S-striking segments, and up to 2 km of displacement occurs at top basement, suggesting that this fault system nucleated at or, more likely, below this structural level. The supra-salt system was active during the Pliocene-Holocene, and is composed of four, NW–SE-striking, listric fault segments, which are soft-linked by unbreached relay zones. Segments in the supra-salt fault system nucleated within Pliocene strata and have maximum throws of up to 482 m. Locally, the segments of the supra-salt fault system breach the Messinian salt to hard-link downwards with the underlying, sub-salt fault system, thus forming the upper part of a fault zone composed of: (i) a single, amalgamated fault system below the salt and (ii) a fault system composed of multiple soft-linked segments above the salt. Analysis of throw-distance (T-x) and throw-depth (T-z) plots for the supra-salt fault system, isopach maps of the associated growth strata and backstripping of intervening relay zones indicates that these faults rapidly established their lengths during the early stages of their slip history. The fault tips were then effectively ‘pinned’ and the faults accumulated displacement via predominantly downward propagation. We interpret that the October Fault Zone had the following evolutionary trend; (i) growth of the sub-salt fault system during the Oligocene-to-early Middle Miocene; (ii) cessation of activity on the sub-salt fault system during the Middle Miocene-to-?Early Pliocene; (iii) stretching of the sub- and supra-salt intervals during Pliocene regional extension, which resulted in mild reactivation of the sub-salt fault system and nucleation of the segmented supra-salt fault system, which at this time was geometrically decoupled from the sub-salt fault system; and (iv) Pliocene-to-Holocene growth of the supra-salt fault system by downwards vertical tip line propagation, which resulted in downward breaching of the salt and dip-linkage with the sub-salt fault system. The structure of the October Fault Zone and the rapid establishment of supra-salt fault lengths are compatible with the predictions of the coherent fault model, although we note that individual segments in the supra-salt array grew in accordance with the isolated fault model. Our study thereby indicates that both coherent and isolated fault models may be applicable to the growth of kilometre-scale, basin-bounding faults. Furthermore, we highlight the role that fault reactivation and dip-linkage in mechanically layered sequences can play in controlling the three-dimensional geometry of normal faults.

Objective Assessment of Foveal Cone Loss Ratio in Surgically Closed Macular Holes Using Adaptive Optics Scanning Laser Ophthalmoscopy

PurposeTo use adaptive optics scanning laser ophthalmoscopy (AO-SLO) to quantify cone loss ratio in the foveola in order to assess foveal cone status and to investigate relationships between foveal structural abnormalities and visual function in patients with macular hole (MH) after surgery.MethodsWe evaluated 10 normal eyes of 10 healthy volunteers and 19 eyes of 18 patients in whom anatomically successful MH closure had been performed. All subjects underwent a comprehensive ophthalmologic examination that included measurements of spectral-domain optical coherence tomography and AO-SLO.ResultsOn AO-SLO regular cone mosaic was seen in all normal eyes whereas dark regions suggesting cone loss were seen in all eyes after MH repair. Visual acuity was better in eyes without dark regions at the center of the fovea than in eyes with them (P = 0.001). Cone loss ratio in the foveola correlated with postoperative visual acuity (P<0.001), mean foveal sensitivity (P = 0.029), thinner inner and outer segments at the center of the fovea (P = 0.002), larger size of the disrupted inner and outer segment junction line (P = 0.018), and cone outer segment tip line (P<0.001). Cone loss ratio in the foveola was significantly greater in eyes that had moderately reflective foveal lesions after surgery (P = 0.006).ConclusionsAO-SLO is a useful means of assessing foveal cone damage objectively and quantitatively. The location and extent of cone damage, especially if it involves the foveola, is an important factor determining visual function after MH surgery.

PHOTORECEPTOR OUTER SEGMENT ABNORMALITIES AND RETINAL SENSITIVITY IN ACUTE ZONAL OCCULT OUTER RETINOPATHY

To investigate the relationship between retinal function and photoreceptor abnormalities in eyes with acute zonal occult outer retinopathy. Five patients with acute zonal occult outer retinopathy underwent complete ophthalmologic examination, including spectral-domain optical coherence tomography. Spectral-domain optical coherence tomography findings were compared with retinal sensitivity measured by microperimetry. Spectral-domain optical coherence tomography images revealed disruptions in the inner segment/outer segment junction line in four of five eyes and disruptions in the outer segment (OS) tip lines in all eyes. Mean retinal sensitivity was 15.1 ± 3.6 dB in the intact OS tip regions and 6.0 ± 6.3 dB in disrupted regions (P < 0.001). In all eyes, disruption of the OS tip lines was also seen in regions of reduced retinal sensitivity, although the inner segment/outer segment was intact. Within the intact inner segment/outer segment regions, mean retinal sensitivity was 7.5 ± 6.7 dB at locations of OS tip disruption and 15.1 ± 3.6 dB at intact OS tip locations (P < 0.001). Structural abnormalities in the photoreceptors were correlated with visual function in eyes with acute zonal occult outer retinopathy. Loss of photoreceptor OS, as indicated by disruptions of the OS tip lines on spectral-domain optical coherence tomography, may represent the primary lesion in acute zonal occult outer retinopathy.

Outer Retinal Morphology and Visual Function in Patients With Idiopathic Epiretinal Membrane

To determine the relationship between the morphology of the fovea and visual acuity in patients with an untreated idiopathic epiretinal membrane (ERM). We examined 52 eyes of 45 patients diagnosed with an ERM. The morphology of the foveal area was determined by spectral-domain optical coherence tomography. The relationships between the best-corrected visual acuity (BCVA) and 8 optical coherence tomography features, central retinal thickness, cone outer segment tip (COST) line, photoreceptor inner/outer segment (IS/OS) junction line, foveal bulge of the IS/OS line, external limiting membrane, inner limiting membrane, foveal pit, and ERM over the foveal center, were evaluated. Multiple regression analysis showed that intact COST line, IS/OS junction line, and external limiting membrane independently and significantly contributed to the BCVA. The standardized partial regression coefficient β was 0.415 for the COST line, 0.287 for the IS/OS junction line, and 0.247 for the external limiting membrane. However, the other features, eg, foveal bulge, inner limiting membrane, foveal pit, and ERM, were not significantly associated with the BCVA. The central retinal thickness was significantly correlated with the BCVA (r2=0.274; P< .01). At an early stage of an ERM, only the photoreceptor structures are significantly associated with the BCVA, and the appearance of the COST line was most highly associated. Detailed examinations of the photoreceptor structures using optical coherence tomography may help find photoreceptor dysfunction in cases of idiopathic ERM.

Analysis of macular cone photoreceptors in a case of occult macular dystrophy

PurposeTo investigate changes in cone photoreceptors with adaptive optics (AO) fundus imaging and spectral domain optical coherence tomography (SD-OCT) in a case of occult macular dystrophy (OMD).Patient and methodsBoth eyes of a 42-year-old woman diagnosed with OMD were examined. We used an AO fundus camera to obtain images of cone photoreceptors in the macula of the OMD subject and five healthy control subjects. Correlations between the AO images and the SD-OCT images were examined. Cone photoreceptors in eight areas in the macula of OMD and healthy control subjects were analyzed and compared.ResultsSD-OCT showed a loss of the cone outer-segment tips line outside of the fovea in both eyes of the subject with OMD. The left eye with decreased visual acuity showed a discontinuous photoreceptor inner-segment and outer-segment line and cone outer-segment tips line at the fovea in SD-OCT and loss of cone mosaics as a dark spot in the AO image. In panoramic AO images and cone-density maps, less cone density was observed in a ring-like region outside the fovea than in the peripheral retina. In most of the areas examined, the cone densities were lower in the OMD eyes than in the healthy control eyes.ConclusionsCone densities in the macula of the OMD patient were greatly decreased. AO images were found to be useful to evaluate morphologic changes in cone photoreceptors in patients with OMD.

Prescriber Education on Opioids

Letters18 December 2012Prescriber Education on OpioidsWilliam C. Becker, MD and David A. Fiellin, MDWilliam C. Becker, MDFrom Yale University School of Medicine, New Haven, CT 06520-8056.Search for more papers by this author and David A. Fiellin, MDFrom Yale University School of Medicine, New Haven, CT 06520-8056.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-157-12-201212180-00019 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail IN RESPONSE:We appreciate Dr. Webster's points and agree that curbing abuse of, addiction to, and overdose deaths from prescription opioids and other controlled substances will require more than provider education. Regarding “pill mills”—a major focus of the Drug Enforcement Administration's efforts—anonymous tip lines have been established in counties with unusually high levels of opioid prescribing. The expansion of such programs should be considered (1). We have a professional and, in some states, a legally mandated duty to report unethical or frankly criminal activity (2).We agree that a national prescription monitoring program makes sense; overcoming logistical barriers to linking ...

Follow‐up study of MEWDS using adaptive optics retinal imaging

AbstractPurpose To study the effects of pathological damage in cone photoreceptor outer segments (OS) on the visibility of cones in adaptive optics (AO) images.Methods Four patients with multiple evanescent white dot syndrome (MEWDS) underwent multimodal retinal imaging using optical coherence tomography (OCT), scanning laser ophthalmoscopy (SLO). AO images were acquired with a field of 4 x 4 deg at eccentricities ranging from 0 to 8 deg from fovea using an infrared flood‐illumination AO camera (rtx1, Imagine Eyes, France). Cone phoreceptor density was measured and analyzed in comparison to the findings from the other imaging modalities. The procedure was repeated at a follow‐up visit after one month. One patient had 3 additional follow‐up examinations over a 10‐month time.Results OCT images showed irregularities and disruptions in the OS tip line. Local thinning of the OS layer was observed in several areas of the macula. AO images revealed marked decreases in the density of detectable cones in the exact same regions. The measured cone density was superior to 30000 cells per mm2 in the areas of normal OS length and dropped to less than 10000 cells per mm2 in the regions of shortened OS. The locations of cone mosaic defects in the AO images also corresponded with hypo‐fluorescent areas observed in the late phase of ICG angiography. During clinical recovery, the progressive return of the IS/OS and the OS tip lines to a normal layered structure in OCT images was correlated to an increase in cone density in AO images.Conclusion AO imaging facilitates detection and monitoring of damage and recovery of the photoreceptor OS during MEWDS. The visibility of cones in AO images seems to be strongly dependent on OS structure and length.

Correlation of Integrity of Cone Outer Segment Tips Line With Retinal Sensitivity After Half-dose Photodynamic Therapy for Chronic Central Serous Chorioretinopathy

To investigate the relationship between the integrity of the photoreceptor microstructures and retinal sensitivity after half-dose photodynamic therapy (PDT) in eyes with chronic central serous chorioretinopathy (CSC). Prospective, noncomparative, interventional case series. Thirteen eyes of 13 patients with chronic CSC who had received half-dose verteporfin PDT were studied. The best-corrected visual acuity (BCVA), macular retinal sensitivity in the central 12 degrees, and optical coherence tomographic (OCT) findings were evaluated at baseline and at 1, 3, 6, and 12 months after the half-dose PDT. The integrities of the external limiting membrane (ELM), the inner segment/outer segment junction (IS/OS) line, and the cone outer segment tips (COST) line were determined. The retinal sensitivity was determined by MP-1 microperimetry. The serous retinal detachment (SRD) was completely resolved in 11 eyes at 1 month and in 1 eye at 3 months. The remaining eye had a persistent SRD throughout the follow-up period. The mean retinal sensitivity was significantly better at 1, 3, 6, and 12 months after the half-dose PDT than at baseline. Before the PDT, 12 eyes had a continuous ELM and 1 eye had a fragmented ELM. The number of eyes with an intact IS/OS line and COST line increased with increasing post-PDT time. At 12 months after PDT, the IS/OS line was detected in 11 eyes and the COST line in 6 eyes. At 6 and 12 months, the retinal sensitivity was significantly higher in eyes with an intact COST line and IS/OS lines than in eyes with an intact IS/OS line only. However, no difference was found in the visual acuity of these 2 groups. The 1 eye with a persistent SRD and another eye with fragmented ELM and absent IS/OS and COST lines through the follow-up periods were associated with poor retinal sensitivity of 8.5 dB and 10.9 dB respectively. Our findings show that there is a significant improvement in the macular sensitivity after half-dose PDT in eyes with chronic CSC. The improvement was correlated with the recovery of the IS/OS and COST lines at 6 and 12 months.

Navigating the New

Navigating the New Mike Meginnis (bio) NewPages, Casey Hill, Publisher. http://www.newpages.com We use the word “blog” as if it were a genre when, really, it is a means of managing content. It says far more about what the site’s administrators see than what the readers do. Of course, you can put anything in a blog—popular contents include fiction, poetry, gobbledygook, news, commentary, polemic, memories, and press releases. If we were to choose one of these categories as most characteristic of the NewPages blog, then it would have to be the press release. The typical post announces the launch of a new magazine, the winners of a contest, or, very occasionally, the publication of a new book from an obscure press, offering the key facts and a quote about how excited the editors are to be sharing these words or what makes this particular project special. These posts seem to be edited versions of public announcements. To the NewPages contributors’ credit, they do an admirable job of trimming much of the empty, self-congratulatory language that characterizes such press releases, rendering them actually readable and potentially useful. It’s not entirely clear how the press releases are selected for publication on the blog. (Is there an email tip line? I don’t see one.) They may be culled from creative writing listservs or the inboxes of the blog’s contributors. Regardless, the results are eclectic: you might expect that a clearinghouse for official statements would be mostly populated with information about Ploughshares and Tin House and The Missouri Review—i.e., operations who can afford to pay people for the intentional manufacture of publicity—but you’re more likely to learn about something new on any given visit than to be reminded of some established literary quantity. On the one hand, this means that there are a lot of stories about things that you are sure to find completely uninteresting. Monthly online journals with weirdly specific editorial missions seem to launch weekly, and NewPages finds room for most of them. On the other hand, this constant sharing of new opportunities is what NewPages is for. Experienced writers familiar with literary magazines and small presses know NewPages. After all, NewPages is not really a blog—it is a comprehensive reference website with many useful lists. They list publications, presses, contests, calls for submissions, creative writing programs, and more. Once you have a sense of what you’re looking for and where your own writing fits in among the rest, this other, larger NewPages becomes easy to manage in spite of a structure and interface that has probably seen little change since the site’s 1999 launch. Initially, however, it can be quite overwhelming, with too much information to process and too little context to help the uninitiated writer. The blog does not provide this context (it lacks the necessary editorial voice, avoiding opinion and controversy as carefully as some lit blogs cultivate the same). Rather, it offers each day one or several entryways to communities and sub-communities that can provide this context. Visitors to the larger NewPages site who feel overwhelmed with all it offers might begin by reading a month of the blog’s content (this will not take too long) and opening, in new tabs, any links that even briefly catch their interest. Most of these will turn out to be duds. Those that retain interest will of course vary according to taste. And this is the point. Once you’ve figured out where your interests lie as a writer, the NewPages blog has largely served its purpose. You can use that knowledge to help you focus your navigation of the site’s other offerings, while other blogs and forums more suited to your particular tastes will most likely replace this general-purpose blog in your daily rotation. But you have to start somewhere, and the NewPages blog offers a better starting point than most, protected by its eclecticism from much of the myopia that more focused communities tend to encourage. The NewPages blog is, like the larger site, very strictly a resource for writers. Even the section of the site that reviews literary...

CLINICAL CHARACTERISTICS OF OCCULT MACULAR DYSTROPHY IN FAMILY WITH MUTATION OF RP1L1 GENE

To report the clinical characteristics of occult macular dystrophy (OMD) in members of one family with a mutation of the RP1L1 gene. Fourteen members with a p.Arg45Trp mutation in the RP1L1 gene were examined. The visual acuity, visual fields, fundus photographs, fluorescein angiograms, full-field electroretinograms, multifocal electroretinograms, and optical coherence tomographic images were examined. The clinical symptoms and signs and course of the disease were documented. All the members with the RP1L1 mutation except one woman had ocular symptoms and signs of OMD. The fundus was normal in all the patients during the entire follow-up period except in one patient with diabetic retinopathy. Optical coherence tomography detected the early morphologic abnormalities both in the photoreceptor inner/outer segment line and cone outer segment tip line. However, the multifocal electroretinograms were more reliable in detecting minimal macular dysfunction at an early stage of OMD. The abnormalities in the multifocal electroretinograms and optical coherence tomography observed in the OMD patients of different durations strongly support the contribution of RP1L1 mutation to the presence of this disease.

Correlation between Length of Foveal Cone Outer Segment Tips Line Defect and Visual Acuity after Macular Hole Closure

To determine whether the postoperative length of the photoreceptor cone outer segment tips (COST) line defect is significantly correlated with best-corrected visual acuity (BCVA) after macular hole closure. Retrospective, consecutive, observational case series. Fifty-one eyes of 51 patients with a surgically closed macular hole were studied. Spectral-domain optical coherence tomography (SD-OCT) was used to obtain images of the foveal area, and the lengths of the COST line defect were measured in the images obtained 1, 3, 6, 9, and 12 months after macular hole surgery. The correlation between the length of COST line defect and the BCVA was determined. The lengths of the COST line defect, the inner segment/outer segment (IS/OS) junction defect, the external limiting membrane (ELM) line defect in the SD-OCT images, and the BCVA. The COST line defect was gradually restored centripetally 1 to 12 months postoperatively. The length of the COST line defect was significantly correlated with the BCVA at 1, 3, 6, 9, and 12 months postoperatively (P < 0.001). Forward stepwise regression analyses showed that the postoperative BCVA was significantly correlated with the length of the COST line defect (P < 0.001) but not with that of the IS/OS junction and ELM line defects after 6 months. The preoperative length of the COST line defect was significantly correlated with postoperative BCVA at 12 months (P = 0.020), but the length of the IS/OS junction and ELM line defects was not. The preoperative length of the COST line defect was significantly longer than the fluid cuff diameter of the macular hole (P = 0.020), indicating that the influence of the elevated neurosensory retina at the fluid cuff on the SD-OCT signals of the COST line was probably minimal. The postoperative BCVA at 12 months can be calculated by the following regression equation: BCVA = 0.00020 × (length of preoperative COST line defect [μm]) - 0.23 (F value = 15.4; P < 0.001). The recovery of the foveal COST line defect is related to visual recovery after macular hole closure. The length of the preoperative COST line defect may predict the BCVA after macular hole surgery.

Mechanics, slip behavior, and seismic potential of corrugated dip‐slip faults

To better understand the mechanics and seismic potential of nonplanar fault surfaces, we present results from a suite of numerical models of faults with sinusoidal corrugations in the downdip direction. Systematic variations in corrugation wavelength, amplitude, and loading angle are introduced to determine the effects on slip behavior and seismic moment release. We find that corrugated faults, in general, slip less than planar faults. Changes in slip behavior are nearly scale‐independent and are dominantly controlled by the amplitude/wavelength of corrugations. Model results suggest that obliquely loaded corrugated faults accumulate less strike slip than a planar fault with the same tip line dimensions and average orientation. This result implies that slip direction is not a reliable indicator of regional stress direction and may at least partially explain repeated, nearly pure dip‐slip coseismic events at oblique plate boundaries. Though the scalar seismic moment release is always less for corrugated fault surfaces due to a greater reduction in slip compared to increased surface area, for geologically reasonable corrugation geometries, changes in total scalar moment release are not significantly different than planar faults. Techniques that utilize highly simplified fault geometries may therefore accurately reproduce scalar moment release but will nonetheless incorrectly predict coseismic slip magnitudes and distributions, as well as regional stress orientations.

Strain compatibility and fault linkage in relay zones on normal faults

Relay zones on normal faults are unlikely to have tabular geometries as depicted in idealised models. Rotation of a relay ramp between non-parallel and non-planar relay-bounding faults will inevitably lead to strain compatibility problems causing open gaps or overlaps within the relay zone. Linkage of relay-bounding faults does not evolve from a single branch point. Rather, linkage occurs at multiple points along the fault tip lines giving rise to initially discontinuous branch lines. Where linkage occurs along a discontinuous slip-aligned branch line, displacement at different levels within the relay zone is partitioned between variable amounts of ramp rotation and slip across the branch line. The linking fault propagates when strain compatibility can no longer be maintained by continuous deformation processes, such as thickening or thinning of incompetent layers within the relay ramp. Step-like changes in vertical displacement vs. distance (d − x) profiles on horizons containing apparently intact relay ramps are probably indicative of incipient breaching and can be used predict the presence of a slip-aligned branch line in the sub-surface. Despite the complexity of the strain distribution within relay zones, the total vertical displacement across the relay remains geometrically coherent at all levels.

Comparison of Screening Procedures in Hydroxychloroquine Toxicity

To compare different screening procedures for hydroxychloroquine sulfate (Plaquenil) toxicity at different stages of damage. Ten patients were studied using 10-2 automated fields, multifocal electroretinography, spectral domain optical coherence tomography (SD-OCT), and fundus autofluorescence. All 10 patients used hydroxychloroquine for more than 6 years, and those with severe toxicity had been overdosed. Fundus examination findings were normal except for the patients with severe toxicity. All the patients showed parafoveal field loss, but this was sometimes subtle. Multifocal electroretinography demonstrated parafoveal weakness in the milder cases. The SD-OCT subfield thickness plots showed a ring of parafoveal thinning in all the patients. The SD-OCT cross-sections showed parafoveal loss of the inner segment-outer segment and cone outer segment tip lines at early stages of toxicity, progressing to parafoveal thinning of the outer nuclear layer and eventually to retinal pigment epithelium damage. There was a ring of autofluorescence in most patients. Overdosage with hydroxychloroquine seemed a significant risk factor for toxicity. Different individuals were more or less sensitive to different tests. Fields can be sensitive but only if read with a low threshold for change. Hydroxychloroquine causes early parafoveal loss of the outer segment lines on SD-OCT, with the first changes often evident in the inferotemporal quadrant. Parafoveal thinning of the outer nuclear layer follows, before retinal pigment epithelium damage is visible. Careful screening with multiple tests can detect toxic damage before prominent loss of the outer nuclear layer.

Highly Reflective Foveal Region in Optical Coherence Tomography in Eyes with Vitreomacular Traction or Epiretinal Membrane

To report the optical coherence tomography (OCT) findings in eyes with vitreomacular traction (VMT) or with an epiretinal membrane (ERM). Retrospective case series. Fifty-four eyes of 45 consecutive patients with subjective visual disturbances resulting from VMT or idiopathic ERM were studied. The morphologic features of the photoreceptor layer at the foveal center were determined and the central foveal thickness (CFT) was measured by spectral-domain (SD) OCT. The morphologic characteristics of the foveal region observed by SD OCT. A roundish or diffuse highly reflective region was observed between the photoreceptor inner segment/outer segment junction line and the cone outer segment tip line at the center of the fovea. This highly reflective region was present in 7 of 7 cases of VMT and 30 of 47 cases of ERM. In the ERM cases, the mean CFT of the cases with the highly reflective region was significantly thicker than that in cases without it. The highly reflective region disappeared when the inward traction on the fovea was released surgically or spontaneously. The highly reflective region is a characteristic sign observed in the OCT images of eyes with VMT and ERM, and it has been termed the cotton ball sign after its appearance. The presence of the cotton ball sign indicates an inward traction on the fovea and may be a predictor of visual impairment.

Foveal Cone Outer Segment Tips Line and Disruption Artifacts in Spectral-Domain Optical Coherence Tomographic Images of Normal Eyes

To determine the incidence of a continuous cone outer segment tips (COST) line at the fovea in spectral-domain optical coherence tomographic (SD-OCT) images of normal eyes. Prospective, interventional case series. Forty-six right eyes of 46 normal individuals with visual acuities (VA) ≥20/20 were studied. SD-OCT images were obtained with a Cirrus HD-OCT instrument with both the standard 5-line raster and the high-definition (HD) 5-line raster scan modes. Images with signal strengths weaker than 5 (on a scale from 0 to 10) were excluded. The appearances of the COST line, photoreceptor inner segment/outer segment (IS/OS) junction, and external limiting membrane (ELM) line were determined in a masked way. The incidence of eyes with an intact foveal COST line was about 95%, and the incidence was not significantly associated with the age, sex, refractive error, signal strength, horizontal or vertical scans, and the use of either the standard or HD scans. Fragmented COST lines appeared to be attributable to blocking artifacts caused by a hyperreflectivity at the foveal surface because the COST fragmentation had corresponding fragmentation of the ELM and IS/OS junction lines. The correlation between a fragmented COST line and the hyperreflectivity on the retinal surface was significant for the vertical HD scans (P = .011) but not for the vertical standard, horizontal standard, or horizontal HD scans. Commercial SD-OCT instruments can detect the COST line. Fragmentations of the COST lines in normal eyes are most likely artifacts caused by a parabolic reflection of a surface hyperreflectivity of the foveal pit.

Significant Correlation Between Visual Acuity and Recovery of Foveal Cone Microstructures After Macular Hole Surgery

To determine whether a recovery of the microstructures of the foveal photoreceptors after macular hole closure is correlated with best-corrected visual acuity (BCVA). Retrospective, consecutive, observational case series. Single-center academic practice. Forty-one eyes of 41 patients with surgically closed macular holes. OBSERVATIONAL PROCEDURES: The presence and intactness of the cone outer segment tips (COST) line were determined by spectral-domain optical coherence tomography and compared with the presence of the inner segment/outer segment (IS/OS) junction and the external limiting membrane (ELM) at 1, 3, 6, 9, and 12 months after the macular hole surgery. The correlation between the integrity of the foveal photoreceptor microstructures and the BCVA. A distinct COST line was first seen at 6 months after the surgery. A distinct or irregular COST line was observed only in eyes with an intact IS/OS junction and ELM. Eyes with a distinct or irregular COST line had significantly better BCVA than those with a disrupted COST line in eyes with an intact IS/OS junction and ELM at 12 months (P = .030). The BCVA was ≥20/25 at 12 months in 91% of the eyes with a distinct or irregular COST line but in only 44% of the eyes without a COST line (P = .015). The significant correlation between the BCVA and a distinct or irregular COST line after successful macular hole surgery indicates that the recovery of foveal cone microstructure is associated with good postoperative BCVA.

Selective Abnormality of Cone Outer Segment Tip Line in Acute Zonal Occult Outer Retinopathy as Observed by Spectral-Domain Optical Coherence Tomography

Selective Abnormality of Cone Outer Segment Tip Line in Acute Zonal Occult Outer Retinopathy as Observed by Spectral-Domain Optical Coherence Tomography