Cranial Neuropathies II, III, IV, and VI
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Generally, three types of visual defects may be seen with optic neuropathies. The most common is generalized constriction of the peripheral field.4 This type of visual field defect can also be caused by other ophthalmic conditions including cataract, retinal degenerations, and nonorganic visual loss. The second type of defect is central visual field loss including central, paracentral, and cecocentral scotomas. These are typically described as a blur, spot, or missing central vision. These also occur in maculopathies. Finally, nerve fiber bundle defects can be seen. They follow the retinotopic pattern of the nerve fibers as they enter the optic nerve, flipped due to the optics of the eye (i.e. superior retina – inferior visual field) (Figure 22.2). They respect the horizontal meridian of the visual field and are termed arcuate defects, nasal steps, or altitudinal defects. This is in contrast to visual field defects due to visual pathway injury at the chiasm or behind the chiasm that respect the vertical meridian (Figure 22.3).
Headache associated with nonvascuiar intracranial disorders
Stephen D. Silberstein, Richard B. Upton, Peter J. Goadsby in Headache in Clinical Practice, 2018
Most patients with papilledema (50–94%) have visual loss,124 which is asymptomatic in 25–50% of patients. However, it is important to measure since it serves as a marker for therapeutic intervention. Perimetry is the main measure used to determine the course of therapy. The visual field defects found in idiopathic intracranial hypertension are the same types as those that are reported to occur in papilledema due to other causes. These ’discrelated defects’ are the same type as those found in glaucoma, although they occur with different frequencies. The most common defects are enlargement of the physiologic blind spot, loss of mferonasal portions of the visual field, and constriction of isopters. Other defects are central, paracentral and cecocentral scotomas, arcuate scotomas, altitudinal patterns of loss, and other nerve fiber bundle defects. The loss of visual field may be progressive and severe and lead to blindness. The onset of visual loss is usually gradual; however, acute, severe visual loss can occur.
The Problems
John Greene, Ian Bone in Understanding Neurology a problem-orientated approach, 2007
For central defects (central scotoma) a small pin is used to map out any area of visual loss. In AION, visual field loss tends to be altitudinal and has a sharp demarcation at the horizontal meridian, whereas optic neuritis is commonly associated with a central area of field loss (scotoma) (96). In the temporal portion of the visual field lies the physiological blind spot: again a pin is used to compare the size of this area between examiner and patient. This technique requires cooperation on the part of the patient, practice by the examiner, and the patience of both. The patient’s gaze must not deviate from the examiner’s pupil (99e). Papilloedema causes an enlarged blind spot and constriction of the visual field. Visual fields are more accurately tested with a Goldmann perimeter machine or other types of visual analyser. This is useful to confirm findings from confrontation, especially the presence of central field defects or an enlarged blind spot, and also to asses change in visual fields over time.
The Treatment of Acute Optic Neuritis
Published in Seminars in Ophthalmology, 2023
Kiandokht Keyhanian, Bart K. Chwalisz
The ONTT presented the largest longitudinal ON cohort to date, and the results from the ONTT continue to inform the treatment of typical ON. In the ONTT, 95% of patients had visual acuity of at least 20/40 and 70% of patients had visual acuity of 20/20 after one year.15 More profound visual field defects at presentation appear to be associated with a higher likelihood of significant and persistent visual field defects. Nevertheless, even in mild cases of typical optic neuritis and with some spontaneous improvement, visual outcome is not guaranteed to return to patient’s baseline.16,17 Also, regaining visual acuity does not necessarily equate to functional visual recovery, as patients often have persistent visual field defects and deficient contrast sensitivity and color saturation.17
Giant cell arteritis
Published in Postgraduate Medicine, 2023
Permanent vision loss: Loss of vision can be partial or complete and can be unilateral or bilateral. Both visual acuity (the ability to spatially distinguish two points in space) and visual fields are impacted [68]. Visual acuity being historically measured by Snellen eye charts. Once vision loss occurs it is essentially irreversible and the prognosis is poor even with prompt initiation of glucocorticoid. In one study of vision loss in 32 patients with biopsy proven GCA; 13% had some improvement in Snellen eye chart readings for visual acuity after corticosteroid initiation [74] but most studies are much less favorable than this outcome with lack of improvement in eyesight and even worsening. If left untreated, vision loss can occur in the unaffected eye in up to 50% of patients in a matter of days [75].
Clinical provision of compensatory visual training after neurological injury: example of a multisite outpatient program
Published in Disability and Rehabilitation, 2021
Megan J. Metzler, Meghan Maiani, Brittany Jamieson, Sean P. Dukelow
Various interventions for visual field loss are reported in the literature. These include remedial training, such as visual discrimination training, substitutive treatment such as prisms, and compensatory methods such as visual scanning training [6]. Drawing conclusions about efficacy is difficult given the heterogeneity of quality and methods [7]; few studies have directly compared these methods. A comparison of dose-matched compensatory and restitution therapy for visual deficits reported favorable outcomes for compensatory treatment, but not restitution therapy after 15 h of intervention [8]. A recent randomized controlled trial compared visual search training, prisms, and usual care [9]. Adverse events of 69% of those in the prism group were reported, while significant improvements in vision-related quality of life with visual search training were found.
Related Knowledge Centers
- Field of View
- Introspection
- Scotoma
- Visual Impairment
- Optical Instrument
- Field of View
- Optometry
- Ophthalmology
- Neurology
- Visual Field Test
- Macula