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At least 19 recordsLinked to original sources
PubMed2006

Optic disk size and optic disk-to-fovea distance in preterm and full-term infants.

PURPOSE: Few studies have assessed optic disk and retinal morphology in infants. Here the optic disk and optic disk-to-fovea distance were measured in preterm and full-term infants in vivo. METHODS: Optic disk (OD) dimensions and the center-to-center distance between the OD and the macula were measured using digital imaging in infants undergoing routine ophthalmic examinations. Postmenstrual age of the mother at the time of examination ranged from 32 to 50 weeks. From each image, the OD-to-fovea distance (ODF) and the OD height (ODH) and OD width (ODW) were measured. RESULTS: In 51 retinal images from 51 infants, mean +/- SD values obtained were 4.4 +/- 0.4 mm (ODF), 1.41 +/- 0.1 9 mm (ODH), and 1.05 +/- 0.13 mm (ODW). These dimensions did not change significantly over the age range studied. The mean value for the ratio between ODF and mean OD diameter (ODF/DD) was 3.76. CONCLUSIONS: Results of this in vivo study suggest that though the optic nerve head diameter increases by more than 50%, only limited growth occurs at the highly organized area of the posterior pole from birth to adulthood. This study discusses the finding of a large-angle kappa in infants and the use of a disk macula/disk diameter ratio in the diagnosis of optic nerve hypoplasia.

Birth Weight↗
PubMed2006

Comparison of retinal nerve fiber layer thickness and optic disk algorithms with optical coherence tomography to detect glaucoma.

PURPOSE: To compare the performance of the retinal nerve fiber layer (RNFL) thickness and optic disk algorithms as determined by optical coherence tomography to detect glaucoma. DESIGN: Observational cross-sectional study. METHODS: setting: Academic tertiary-care center. study population: One eye from 42 control subjects and 65 patients with open-angle glaucoma with visual acuity of > or =20/40, and no other ocular pathologic condition. observation procedures: Two optical coherence tomography algorithms were used: "fast RNFL thickness" and "fast optic disk." main outcome measures: Area under the receiver operating characteristic curves and sensitivities at fixed specificities were used. Discriminating ability of the average RNFL thickness and RNFL thickness in clock-hour sectors and quadrants was compared with the parameters that were derived from the fast optic disk algorithm. Classification and regression trees were used to determine the best combination of parameters for the detection of glaucoma. RESULTS: The average visual field mean deviation (+/-SD) was 0.0 +/- 1.3 and -5.3 +/- 5.0 dB in the control and glaucoma groups, respectively. The RNFL thickness at the 7 o'clock sector, inferior quadrant, and the vertical C/D ratio had the highest area under the receiver operating characteristic curves (0.93 +/- 0.02, 0.92 +/- 0.03, and 0.90 +/- 0.03, respectively). At 90% specificity, the best sensitivities (+/-SE) from each algorithm were 86% +/- 3% for RNFL thickness at the 7 o'clock sector and 79% +/- 4% for horizontal integrated rim width (estimated rim area). The combination of inferior quadrant RNFL thickness and vertical C/D ratio achieved the best classification (misclassification rate, 6.2%). CONCLUSION: The fast optic disk algorithm performs as well as the fast RNFL thickness algorithm for discrimination of glaucoma from normal eyes. A combination of the two algorithms may provide enhanced diagnostic performance.

Adult↗
PubMed1993

Differences of retinal nerve fiber layer thickness between normal and glaucoma-like optic disks (physiological cups) matched by optic disk area.

We matched by disk area size 23 eyes of patients with glaucoma-like disks (physiological cups) with normal ocular pressures and no visual field loss with 23 eyes of normal subjects. Using stereophotogrammetry we found a significant decrease in retinal nerve fiber layer thickness in the eyes with glaucoma-like disks compared to the normal eyes (P = 0.0081), especially in the nasal quadrant (18.1%). A similar significant decrease was noted in the neuroretinal rim area and a significant increase in cup volume, area, depth and slope for the total disk and its quadrants. The use of computerized image analysis also showed a significant increase in pallor area for glaucoma-like disks compared to normal disks. Eyes with glaucoma-like disks or physiological cups showed evidence of an optic neuropathy and may be manifesting the same damage to the optic nerve occurring in high pressure open angle glaucoma.

Aged↗
PubMed1984

Enlargement of the optic disk in childhood optic nerve tumors.

Two children, a 9-year-old girl and an 8-month-old girl, were first examined because of unilateral proptosis. Both children were found to have unilateral optic nerve glioma, accompanied in the second case by neurofibromatosis. Two years after Patient 1 was first examined, the initial findings of thin vertical retinal striae and a gray opacification of the peripapillary retina had resolved. The enlarged left optic disk had an average diameter of 2 mm while that of the normal right optic disk was 1.6 mm. The disk-arteriolar ratio was R.E.:16:1 and L.E.: 20:1. Four years later, the patient's visual acuity was still 20/20 in both eyes and the only visual field abnormality was an enlarged blind spot corresponding to the enlarged left optic nerve head. Fundus photographs, orbital echography, and computed tomography showed no change in the size or location of the optic nerve glioma during the six-year follow-up period. In Case 2, the initial intraocular pressure was higher in the proptotic right eye than in the left eye (25 vs 19 mm Hg), but subsequent intraocular pressures were within normal limits and approximately equal in the two eyes. The disk-arteriolar ratio was R.E.:21:1 and L.E.: 18:1 and the cup-disk ratio was R.E.: 0.7 and L.E.: 0.3. Computed tomography disclosed an enlarged right retrobulbar optic nerve, a superior orbital fissure that was much larger on the right than on the left, and a larger cavernous sinus on the right. The right sphenoid bone was partially absent. Despite mild developmental delay, the patient's visual acuity apparently remained normal and the ophthalmologic findings did not change significantly during the 18-month follow-up period.

Child↗
PubMedDate not supplied

Optic disk drusen.

Optic disk drusen occur in 3.4 to 24 per 1,000 population and are bilateral in approximately 75%. Disturbance in the axonal metabolism in the presence of a small scleral canal--regardless of eyelength--is considered responsible for the development. The drusen increase in size, becoming more visible with age due to continuing calcium apposition, and they are associated with visual field defects in a considerable number of patients. Patients do not usually notice these defects, despite their progressive nature over the years, and this indicates an insidious course. A correct diagnosis of optic disk drusen is mandatory, although effective treatment is not yet available. It is most important to differentiate optic disk drusen from papilledema in order to avoid unnecessary neurological examinations, but also to avoid overlooking genuine neurologic disorders. Because optic disk drusen can cause severe visual field defects, patients require individual consultation regarding work issues and whether or not to drive. Optic disk drusen can be accompanied by vascular complications as well. In some cases these vascular changes--for example, choroidal neovascularization--are treatable. Patients with optic disk drusen should undergo regular visual field, IOP, and nerve fiber layer examinations. In patients with deteriorating visual field and borderline IOP, we recommend antiglaucomatous therapy.

Diagnosis, Differential↗
PubMed1993

Converting to an optical disk system.

Optical disk technology is a move to the future. It is an exciting time to brave the new frontiers and change from a manual to an optical disk system. Since the technology is so new in health care environments and because each facility is unique, there is no "right" way to do optical imaging. Opportunities flourish to "do it your way." The process is challenging and time consuming, but the rewards of providing health information users with a quality record system make the investment worthwhile. Complete, thorough planning and education will ease the transition to tomorrow's system. Stop dreaming, make a commitment, and move forward--optical disk systems in health care are achievable successes!

Capital Expenditures↗
PubMedDate not supplied

[Optic disk drusen].

Optic disk drusen (ODD) is a much more prevalent condition than it is usually considered. It is important to recognize ODD in order to escape serious neurosurgical interventions and rule out the development of optic neuropathy leading to grave visual dysfunction. Three cases with ODD are described. The authors conclude that it is an acquired disease, which can be bi- and unilateral. Initial diagnosis "suspected congestive optic disk of both eyes" was erroneous in all cases and it was replaced by "pseudocongestion" because of ODD. A characteristic symptom of ODD is narrowing of visual field borders and presence of scotomas in the lower half of central visual field. Since ODD are a manifestation of progressive optic neuropathy leading to disorders in the central visual field, dedystrophic and (if necessary) ophthalmo-hypotensive therapy is to be carried out.

Adolescent↗
PubMed1977

The histologic basis of optic disk pallor in experimental optic atrophy.

We studied the clinical and microscopic appearances of the optic nerve head in squirrel monkeys with optic nerve degeneration produced by optic nerve transection at the orbital apex. The ophthalmoscopic development of optic disk pallor coincided with the loss of nerve fiber bundles and the rearrangement of the remaining disk astrocytes into dense parallel layers across the nerve head. No astrocytic mitoses were observed and the estimated volume of astrocytes increased only slightly from normal. Among the astrocytes in atrophic disks, many capillaries had patent lumens and ultrastructurally normal endothelial cells. Pallor of the optic disk seems to result from a decrease in the transmission of light into the cytoarchitecture of the atrophic nerve head, not from the absence of capillaries or from extensive astrocytic proliferation.

Animals↗
PubMedDate not supplied

Optic disk manifestation in diabetic eyes with low serum albumin: late fluorescein staining and high blood flow velocities in the optic disk.

PURPOSE: To evaluate ocular findings and blood flow characteristics in diabetes mellitus (DM) patients with low serum albumin (ALB). METHODS: We studied 106 eyes of 53 type II DM patients without proliferative diabetic retinopathy and panretinal photocoagulation. All underwent standard ophthalmic examinations, color Doppler imaging, and serum ALB measurements. The patients were divided into Group 1 (34 cases) with a serum ALB > or =3.8 g/dl and Group 2 (19 cases) with ALB<3.8 g/dl. RESULTS: All of the optic disks appeared normal by Ophthalmoscopy except one case with the lowest serum ALB. The number of optic disks showing late fluorescein staining was significantly higher in Group 2 than in Group 1. Peak systolic velocities in the central retinal artery (CRA, P=0.02) and central retinal vein (CRV, P<0.001) were significantly higher in Group 2, and significantly correlated with the serum ALB value (CRA; r=0.41, P=0.003 and CRV; r=0.60, P<0.001). CONCLUSIONS: We suggest that low serum ALB enhances the permeability of the vessels in or around the optic disk and induces subclinical optic disk edema, which is characterized by late fluorescein staining and high blood flow velocities in the CRA and CRV.

Aged↗
PubMed1988

Operational radiologic image archive on digital optical disks.

A digital optical disk archive for storage of computed radiographic, computed tomographic, magnetic resonance, ultrasonographic, and digitized film radiographic images was installed. In the system, digital images enter a minicomputer, are temporarily stored on magnetic disks, and are archived onto write-once read-many optical disks at their full resolution. A pictorial index of minified images is maintained for each patient. After 8 months of operation, 49,400 megabytes of images had been retained on 19 optical disks stored, after January 1987, in a mechanical jukebox-style optical disk library. The success rate for archival capture of images during the initial period was 96.6%. The failures were due to overfilling of the magnetic disk, a problem addressed through the addition of a second magnetic disk unit. There were no medium-related image errors during the early period. Problems resulting from the slow speed of optical disk systems were addressed operationally by initiating recall of a patient's archived images from the optical to the faster magnetic disk as soon as the system received a request to acquire a new image. Also, optical disk retrieval times are expected to improve with technologic development.

Electronic Data Processing↗
PubMed1988

Optic disk size in ischemic optic neuropathy.

We measured the horizontal diameter, vertical diameter, and area of the optic disk in fellow eyes of patients with unilateral nonarteritic ischemic optic neuropathy and in control eyes without ocular disease. The fellow eyes of patients with anterior ischemic optic neuropathy had a smaller horizontal than vertical disk diameter (P less than .05), a difference not present in controls. Both the horizontal disk diameter and the disk area were significantly smaller in fellow eyes of patients with anterior ischemic optic neuropathy than in controls (P less than .05). There was no statistical difference in the vertical disk diameters between the two groups. Our findings suggest that a small disk area along with a horizontal shortening of the scleral canal can lead to crowding of optic nerve fibers, predisposing to a circulatory compromise of the optic nerve head in non-arteritic anterior ischemic optic neuropathy.

Adult↗
PubMed1990

The optic disk in anterior ischemic optic neuropathy associated with retinal artery occlusion.

Two patients who had retinal artery occlusion associated with impaired peripapillary choroidal circulation were followed up ophthalmoscopically, to evaluate the appearance of the optic disk. The first patient showed central retinal artery occlusion, and the second patient demonstrated branch retinal artery occlusion. A peripapillary choroidal filling defect was noted in both cases by fluorescein angiography, suggesting an association with anterior ischemic optic neuropathy. The first patient exhibited optic atrophy without demonstrating pale disk edema. The second patient showed pale disk edema, but a sectorial defect of disk swelling was noted in the quadrant that corresponded to the area affected by branch retinal artery occlusion.

Aged↗
PubMed2005

Compact description of substrate-related aberrations in high numerical-aperture optical disk readout.

Optical disks are read out by focusing a beam of high numerical aperture (NA) through the substrate. Deviations of the thickness from the nominal value result in spherical aberration; tilting the substrate results in coma. Exact analytical expressions for the rms aberration per micrometer thickness mismatch (for spherical aberration) and per degree tilt (for coma) are derived. The paraxial estimates for these sensitivities proportional to NA4 (spherical aberration) and NA3 (coma) underestimate the exact values by a factor of approximately 2 for the value NA = 0.85, corresponding to the new Blu-ray disk format. Expansion of the aberration function in Zernike aberrations shows that the exact aberration functions are well described by the lowest-order Zernike spherical aberration (A40) and coma (A31) term for all but the very highest NA values.

Journal Article↗
PubMed1986

The correlation between cup-disk ratio, neuroretinal rim area, and optic disk area measured by the video-ophthalmograph (Rodenstock analyzer) and clinical measurement.

The video-ophthalmograph (Rodenstock analyzer) records the topography of the optic disk via simultaneous stereoscopic video images which are stored and analyzed with the help of a microcomputer. We performed a prospective study of 49 eyes of 49 patients to compare the vertical cup-disk ratio, the horizontal cup-disk ratio, the neuroretinal rim area, and the optic disk area obtained with the video-ophthalmograph with those obtained with manual analysis of black-and-white stereoscopic photographs. The correlation coefficients were 0.67, for vertical cup-disk ratio (P = .0000), 0.63 for horizontal cup-disk ratio (P = .0000), 0.72 for neuroretinal rim area (P = .0000), and 0.89 for optic disk area (P = .0000).

Computers↗