The intrinsically restructured fovea is correlated with contrast sensitivity loss in Parkinson's disease.

Foveal structure that is specified by the thickness, depth and the overall shape of the fovea is a promising tool to qualify and quantify retinal pathology in Parkinson's disease. To determine the model variable that is best suited for discriminating Parkinson's disease eyes from those of healthy controls and to assess correlations between impaired contrast sensitivity and foveal shape we characterized the fovea in 48 Parkinson's disease patients and 45 control subjects by optical coherence tomography (OCT). The model quantifies structural changes in the fovea of Parkinson's disease patients that are correlated with a decline in contrast sensitivity. Retinal foveal remodeling may serve as a parameter for vision deficits in Parkinson's disease. Whether foveal remodeling reflects dopaminergic driven pathology or rather both dopaminergic and non-dopaminergic pathology has to be investigated in longitudinal studies.

A novel retinal biomarker for Parkinson's disease: Quantifying the foveal pit with optical coherence tomography.

BACKGROUND: Optical coherence tomography offers a potential biomarker tool in Parkinson's disease (PD). A mathematical model quantifying symmetry, breadth, and depth of the fovea was applied. METHODS: Nintey-six subjects (72 PD and 24 healthy controls) were included in the study. Macular scans of each eye were obtained on two different optical coherence tomography devices: Cirrus and RTVue. RESULTS: The variables corresponding to the cardinal gradients of the fovea were the most sensitive indicators of PD for both devices. Principal component analysis distinguished 65% of PD patients from controls on Cirrus, 57% on RTVue. CONCLUSION: Parkinson's disease shallows the superior/inferior and to a lesser degree nasal-temporal foveal slope. The symmetry, breadth, and depth model fits optical coherence tomography data derived from two different devices, and it is proposed as a diagnostic tool in PD.

Buried disc drusen have hypo-reflective appearance on SD-OCT.

PURPOSE: Buried disc drusen are an important differential diagnosis for papilledema. Spectral domain optical coherence tomography (SD-OCT) affords clinicians with new non-invasive opportunities to probe below the surface of the optic nerve. Clinicians may use the knowledge of this appearance to rule out buried disc drusen in patients with irregular optic nerve borders or a bulging, hyperemic appearance. METHODS: SD-OCTs were obtained in a patient with one surfacing disc druse, identifying the nature of the appearance of this disc druse and others in this and the contralateral eye when imaged with this technology. B-scan ultrasonography was used to confirm the presence of disc drusen. Additional scans in multiple patients with confirmed buried drusen were obtained for comparison. RESULTS: Drusen appear as rounded hyporeflectant areas on SD-OCT, similar in appearance to blood vessels. They share the appearance of cysts but show a fine hyperreflective border anteriorly. These same discrete hyporeflective areas were found at various depths within optic nerve heads with confirmed buried disc drusen. CONCLUSIONS: The hyporeflective appearance may not be anticipated by clinicians, as B-scans show calcified drusen as hyperreflective on echo. It is hypothesized that the hyporeflectant appearance of drusen is due to a constancy in refractive index through the druse, as OCT detects changes in optical reflectivity. Thus, drusen are likely dense and homogenous. SD-OCT may be more useful in those patients with buried disc drusen which are not calcified as B-scan often contributes little in such cases.

Panoramic autofluorescence: highlighting retinal pathology.

PURPOSE: Recent technological advances in fundus autofluorescence (FAF) are providing new opportunities for insight into retinal physiology and pathophysiology. FAF provides distinctly different imaging information than standard photography or color separation. A review of the basis for this imaging technology is included to help the clinician understand how to interpret FAF images. Cases are presented to illustrate image interpretation. METHODS: Optos, which manufactures equipment for simultaneous panoramic imaging, has recently outfitted several units with AF capabilities. Six cases are presented in which panoramic autofluorescent (PAF) images highlight retinal pathology, using Optos' Ultra-Widefield technology. Supportive imaging technologies, such as Optomap® images and spectral domain optical coherence tomography (SD-OCT), are used to assist in the clinical interpretation of retinal pathology detected on PAF. RESULTS: Hypofluorescent regions on FAF are identified to occur along with a disruption in the photoreceptors and/or retinal pigment epithelium, as borne out on SD-OCT. Hyperfluorescent regions on FAF occur at the advancing zones of retinal degeneration, indicating impending damage. PAF enables such inferences to be made in retinal areas which lie beyond the reach of SD-OCT imaging. PAF also enhances clinical pattern recognition over a large area and in comparison with the fellow eye. Symmetric retinal degenerations often occur with genetic conditions, such as retinitis pigmentosa, and may impel the clinician to recommend genetic testing. CONCLUSIONS: Autofluorescent ophthalmoscopy is a non-invasive procedure that can detect changes in metabolic activity at the retinal pigment epithelium before clinical ophthalmoscopy. Already, AF is being used as an adjunct technology to fluorescein angiography in cases of age-related macular degeneration. Both hyper- and hypoautofluorescent changes are indicative of pathology. Peripheral retinal abnormalities may precede central retinal impacts, potentially providing early signs for intervention before impacting visual acuity. The panoramic image enhances clinical pattern recognition over a large area and in comparison between eyes. Optos' Ultra-Widefield technology is capable of capturing high-resolution images of the peripheral retina without requiring dilation.

Pervasive ocular anomalies in posterior microphthalmos.

BACKGROUND: Posterior microphthalmos is a relatively rare condition that has been reported to coexist with several other ophthalmic conditions. However, to the best of the authors' knowledge, there are no previous reports that have found posterior microphthalmos and refractive, binocular, retinal, and neurologic considerations, along with a possible hereditary component. The following report documents the coexistence of posterior microphthalmos with severe hyperopia, esotropia, macular folds, and optic nerve hypoplasia in a pair of siblings. CASE REPORT: A 9-year-old Hispanic girl presented for a comprehensive eye examination. Best-corrected visual acuity (VA) was reduced in both eyes with poorer VA in the right eye. Binocular testing found a small angle constant right esotropia (ET). On dilated fundus examination, a peculiar, elevated, dolphin-shaped folding of the macula was identified, the right eye greater than the left eye, that extended toward an anomalous optic nerve head in both eyes (OU), presumed to be a disc hypoplasia. The patient's brother, who also exhibited severe hyperopia and ET, presented with a similar acuity reduction, a nearly identical folded macular appearance, the right eye more so than the left eye, and a probable optic nerve hypoplasia. Pachymetry, ultrasonography, and ocular coherence tomography imaging of both siblings found thickened corneas in the presence of posterior microphthalmos OU and macular folds affecting only the retina, leaving the choroid and sclera unaffected. CONCLUSIONS: Posterior microphthalmos may exist in the presence of ocular anomalies along with refractive, binocular, retinal, neurologic, and genetic considerations. In this case, optical coherence tomography provided information on the internal morphology of the macular folds, which helped direct the differential diagnosis. The similar presentation among siblings supports a hereditary component that warrants further investigation.

Novice Reviewers Retain High Sensitivity and Specificity of Posterior Segment Disease Identification with iWellnessExam™.

Introduction. Four novices to Spectral Domain Optical Coherence Tomography (SD-OCT) image review were provided a brief lecture on the interpretation of iVue iWellnessExam™ findings (available on iVue® SD-OCT, Optovue, Inc., Fremont, CA). For a cohort of 126 (Confirmed) Normal, 101 (Confirmed) Disease subjects, iWellnessExam™ OD, OS, and OU reports were provided. Each novice independently reviewed and sorted the subjects into one of four categories: normal, retinal disease, optic nerve (ON) disease, and retinal + ON disease. Their accuracy is compared between the novices and with an expert reviewer. Results. Posterior segment disease was properly detected by novices with sensitivities of 90.6%, any disease; 84.3%, retinal disease; 88.0%, ON disease; expert sensitivity: 96.0%, 95.5%, and 90.0%, respectively; specificity: 84.3%, novices; 99.2%, expert. Novice accuracy correlates best with clinical exposure and amount of time spent reviewing each image set. The novices' negative predictive value was 92.0% (i.e., very few false negatives). Conclusions. Novices can be trained to screen for posterior segment disease efficiently and effectively using iWellnessExam™ data, with high sensitivity, while maintaining high specificity. Novice reviewer accuracy covaries with both clinical exposure and time spent per image set. These findings support exploration of training nonophthalmic technicians in a primary medical care setting.

Glaucoma without cupping.

BACKGROUND: Although glaucoma can exist with normal intraocular pressures (IOPs), clinicians still rely on the presence of a large cup to "flag" suspects, regardless of IOP, whereas a small cup at the same pressure level is often ignored. High-tech instruments offer a new dimension of evaluation in the objective assessment of structure when subjective tests of function and/or ophthalmoscopic observations are equivocal. CASE REPORTS: Thirteen cases are presented and show evidence of glaucoma based on glaucomatous visual-field defects, often with steadily rising intraocular pressures and retinal nerve fiber layer loss. Surprisingly, these patients maintained small C/D ratios. Accordingly, ophthalmoscopy and/or disk topography classified these disks as normal. CONCLUSIONS: Although unrecognized in virtually the entire world's ophthalmic literature, normal cup glaucoma is a real clinical entity. At least half the normal cup glaucoma cases presented herein have disk drusen (obvious, subtle, or occult), while others are highly myopic and/or have documented IOP spikes. Several of the cases defy classification and explanation at the present time.

Sensitivity and specificity of the iVue iWellnessExam™ in detecting retinal and optic nerve disorders.

BACKGROUND: The purpose of this study was to assess the specificity and sensitivity of the iWellnessExam™ screening protocol available on iVue® spectral domain optical coherence tomography (SD-OCT), in a cohort of confirmed normal subjects and subjects with confirmed disease. METHODS: In total, 126 of 132 confirmed normal subjects and 101 of 107 subjects with confirmed disease were included for analysis. Of the patients with confirmed disease, 67 had retinal disease, 50 had optic nerve disease, and 16 had both retinal and optic nerve pathology. All subjects were screened on the iWellnessExam protocol. Screen shots of the OD, OS, and OU comparison data were obtained and deidentified for reviewer analysis. Based on these data alone, each subject was sorted by a well trained eye care clinician into one of four categories (1, normal; 2, retinal disease; 3, optic nerve disease; 4, retinal and optic nerve disease). RESULTS: Of the confirmed normal subjects, 125 of 126 were correctly identified as normal (specificity 99%). Retinal and/or optic nerve disease was correctly detected in 97 of 101 patients with confirmed disease (category 2, 3, 4), retinal pathology was correctly detected in 64 of 67 patients with retinal disease (category 2, 4), and optic nerve pathology was properly detected in 45 of 50 patients with optic nerve disease (category 3, 4), with a sensitivity of 96%, 95.5%, and 90%, respectively. CONCLUSION: The iWellnessExam offers the health care provider an excellent method for identifying eyes at risk using very reliable technology. High specificity and sensitivity was obtained when reviewed by a well trained eye care clinician. It would be valuable to repeat the study with a novice and/or student clinician reviewing the same data set to ascertain interobserver variability, as well as the impact of clinical experience on accurate referral, based on the screening data.

Discordance between structure and function in glaucoma: Possible anatomical explanations.

PURPOSE: The aim of this study was to analyze glaucomatous eyes that show discordance between structure and function and hypothesize plausible anatomical explanations for discordance. METHODS: Fifty eyes from 50 consecutive subjects with glaucoma (which was diagnosed according to multicenter criteria) were studied. One eye from each subject was selected randomly for inclusion, counterbalancing right eye (O.D.) and left eye (O.S.). By comparing the available structural information (from clinical disc assessment as well as GDx retinal nerve fiber layer [RNFL] measurements) to the Swedish Interactive Threshold Algorithm (SITA) Standard 24-2 (SS24-2) visual field results, study eyes were assigned to the following categories: (1) positive structure-function correlation, (2) structural abnormalities with no functional deficits, and (3) functional abnormalities with no structural deficits. Structure and function also were compared on a statistical basis, utilizing the nerve fiber indicator (NFI) of the GDx and the mean deviation (MD) and pattern standard deviation (PSD) of SS24-2 visual fields. RESULTS: Forty-four eyes were classified in category 1, 5 eyes in category 2, and 1 eye in category 3. Scatter plots showing the relationship between the NFI and MD and between the NFI and PSD depict a positive correlation in the 44 category 1 eyes with R(2) values of 0.465 and 0.322, respectively. The remaining 6 eyes with discordant structural and functional findings were analyzed in detail. CONCLUSION: The majority (88%) of glaucoma cases show concordance between structural loss and functional deficits. The primary proposed explanations for discordance include (1) visual field sampling and test selection limitations (i.e., the SS24-2 samples only axons that are anatomically connected to photoreceptors in the central retina, whereas the GDx samples virtually all axons) and (2) GDx measurement limitations in the papillo-macula bundle (i.e., the GDx has difficulty differentiating the normally thin RNFL from the pathologically even thinner RNFL). Tests of both structure and function are recommended in glaucoma suspects and patients, as neither mode is capable of identifying all glaucomatous deficits. Due to the apparent diagnostic benefit that the peripheral functional data may provide, we strongly recommend that future studies evaluating the structure-function relationship in glaucoma record peripheral (60-4) visual fields for all subjects at the outset of the study.