Ординатура / Офтальмология / Английские материалы / Field of Vision A Manual and Atlas of Perimetry_Barton, Benatar_2003

DISCUSSION

Field description: Inferior arcuate defect with inferiorly enlarged blind spot OS.

Localization: Optic nerve.

Pathology: Optic disc vasculitis.

Confrontation fields were normal.

Fluorescein angiography confirmed mild disc edema with late disc leakage. Together with the cotton wool spot and nerve fiber layer hemorrhage, this suggested an optic disc vasculitis. The arcuate defect is the result of focal ischemia of the nerve fiber layer at the location of the cotton wool spot (arrow), which corresponds to the site of the inferior enlargement of the blind spot.

The features of optic disc vasculitis are the sudden onset of unilateral mild visual impairment in a relatively young adult, with relatively preserved acuity despite optic disc edema and enlarged retinal veins. The patient would correspond to what Hayreh has called “type 1” optic disc vasculitis, with exudates on the disc or peripapillary retina and minor degrees of nerve fiber layer hemorrhages (10). Other terms used for this include papillophlebitis, or benign retinal vasculitis. The cause is unclear. Mononuclear cell infiltrates within the wall of the central retinal artery and surrounding the central retinal vein were identified in one case (11). Usually no underlying systemic inflammatory disorder is found. Steroids are recommended by some, but the course is benign with recovery over many months (10). With time and without specific treatment, this patient’s signs gradually resolved and her visual field defect improved over the next year..

DISCUSSION

Field description: Inferior perifoveal scotoma OS.

Localization: Retina.

Pathology: Branch retinal arterial occlusion.

Confrontation testing showed a perifoveal scotoma OS to red targets, also apparent on the Amsler grid.

The patient has a defect within the central 5°, but acuity is normal, hence the fovea is spared, making this a central perifoveal defect. The defect is clearly monocular, and only partly respects the horizontal meridian, in the more peripheral extent of the defect. It is an

unusual defect and an unusual presentation for a retinal artery occlusion, but fundoscopy clearly showed a small plaque at the terminus of an arteriole in the region of the abnormality. Focal electroretinography confirmed a zone of nonfunctioning retina in this region also. Investigations for young stroke were done (see Case 9), with negative results. Field defects associated with hallucinations suggest a release phenomenon, but release requires that an area of the field have lost visual input from both eyes. This is clearly not the case here. One can speculate that his hallucinations may be due to some retinal instability in surviving neuronal elements, possibly more likely given the relatively minimal nature of his ischemic defect.

HISTORY AND EXAM

This 44-yr-old man had an 18-year history of non-Hodgkin lymphoma involving the abdomen, pelvis, and cervical nodes, and, in the prior year, pulmonary involvement. For 2 weeks he had unusual frontal headaches daily and for 3 days painless blurred vision OS.

Visual acuity was 20/20 OD and 20/30 OS. Color vision was normal. There was no RAPD. Fundoscopy showed a few pale raised choroidal lesions in the left eye in the temporal retina.

DISCUSSION

Field description: Relative nasal scotoma OS, partially refractive. Localization: Retina/choroid.

Pathology: Choroidal metastasis from lymphoma.

Confrontation testing showed nasal blurring for hand comparison, but red targets appeared normal in this region.

Note that the patient’s nasal field defect does not respect the horizontal meridian or appear arcuate in shape. This points away from the optic nerve, which can be involved by lymphoma. Part of the defect shrinks with use of a +3.00 sphere, indicating that some of it is refractive in origin, from elevation of the retina out of the plane of focus. Choroidal metastasis was confirmed with an orbital ultrasound, which shows this elevation (arrow).

The choroid may be involved by metastatic non-Hodgkin lymphoma as well as primary central nervous system (CNS) lymphoma (14). With metastatic non-Hodgkin lymphoma, there is typically concurrent involvement of the brain parenchyma, though not present in this patient. The lymphoma initially involves the space between the choroid and the retinal pigment epithelium and the vitreous becomes cloudy, being filled with inflammatory and neoplastic cells. Definitive diagnosis of choroidal lymphoma can be made by cytologic examination of a vitreous aspiration. This procedure is particularly useful when primary CNS lymphoma is suspected, but there is no focal lesion amenable to biopsy and lumbar puncture fails to reveal malignant cells. With combined involvement of the brain parenchyma and the choroid, treatment consists of whole brain and ocular irradiation. If isolated to the eye, ocular irradiation is the treatment of choice.

HISTORY AND EXAM

This 53-yr-old man described a 25-year history of episodes of flashes of light lasting 10–15 seconds occurring on awakening and with transition between light and dark environments. These had become gradually more frequent over a few years. He also noted

some diminution of his peripheral vision, especially at night, and a periodic flickering sensation in his peripheral vision. There was no relevant family history. Visual acuity was 20/20 OD and 20/25 OS. Ishihara color plates were 13/14 OU.

DISCUSSION

Field description: Bilateral hemi-ring scotomata predominantly in the temporal fields.

Localization: Retina.

Pathology: Retinitis pigmentosa.

Confrontation fields showed decreased finger counting in the temporal fields.

Note that these temporal field deficits do not respect the vertical meridian (cf. Case 65) and spare the far periphery. Fundoscopy (shown here) showed spicules of pigment and attenuated arterioles in the retinal periphery. Full-field electroretinograms (ERGs) were reduced OU, consistent with the diagnosis of retinitis pigmentosa.

Retinitis pigmentosa is a term that encompasses a range of genetically heterogeneous diffuse photoreceptor-retinal pigment epithelial disorders. The inheritance pattern is vari-

able, with autosomal dominant, autosomal recessive, and X-linked patterns (15). Some forms are due to mutations in the rhodopsin gene (16). The rod photoreceptors usually bear the brunt of the early degenerative changes, and initial symptoms typically include slowly progressive binocular loss of dark adaptation and night vision (nyctalopia). Fields show ring scotomata, typically between 20 and 40° eccentricity initially. Some forms are more focal; in this case, selective pigmentary degeneration of the nasal retina resulted in a field defect that mimicked bitemporal hemianopia. The onset of symptoms varies from infancy to middle age and tends to occur earliest in the X-linked variety and latest in autosomal dominant forms (15). With advanced disease, the visual fields may become markedly constricted with relative sparing of central vision.

HISTORY AND EXAM

This 62-yr-old woman had a superotemporal field defect OS discovered incidentally 15 years prior at a visit for chronic headache. Magnetic resonance imaging (MRI) then

showed a foramen magnum meningioma. Visual acuity was 20/20 OD and 20/25 OS, and color plates were normal OU. There was no RAPD.