ABSTRACT
The arrangement of the ocular dominance columns in the human primary visual cortex was studied by examining cytochrome oxidase activity in autopsy specimens of occipital lobes obtained from two patients who became blind in one eye before death. By artificially flattening the cortex before processing, it was possible to reconstruct the pattern formed by the ocular dominance columns throughout most of the primary visual cortex. The columns form a mosaic of irregular parallel stripes about 500 microns to 1000 microns wide (right eye column plus left eye column measures 1 to 2 mm), oriented at right angles to the boundary of the primary visual cortex. The columns are wider near the boundary of the primary visual cortex and within the representation of the peripheral visual field, the ocular dominance columns of the ipsilateral eye become fragmented until they disappear altogether at the border of the monocular crescent representation. The arrangement of ocular dominance columns in the human visual cortex is very similar to the pattern reported in the macaque monkey, although the columns in humans are wider.
Subject(s)
Dominance, Cerebral , Ocular Physiological Phenomena , Visual Cortex/pathology , Aged , Blindness/diagnostic imaging , Brain Mapping , Dominance, Cerebral/physiology , Electron Transport Complex IV/metabolism , Humans , Male , Middle Aged , Tomography, X-Ray ComputedABSTRACT
We studied the refractive status of 13 children with Leber's congenital amaurosis. Seven had the disease complicated by neurological or other systemic abnormalities, while the other 6 patients had only ophthalmic abnormalities. All 13 patients were hyperopic. The magnitude of hyperopia did not differ significantly between the complicated and uncomplicated groups. Therefore, one cannot, as previously suggested, use the presence of high hyperopia to differentiate an uncomplicated form of Leber's congenital amaurosis from one complicated by neurologic or other systemic abnormalities. The concurrence of hyperopia with Leber's congenital amaurosis should not steer the physician away from careful neurologic systemic or biochemical evaluation of the child.
Subject(s)
Blindness/congenital , Hereditary Sensory and Motor Neuropathy/physiopathology , Hyperopia/physiopathology , Optic Atrophies, Hereditary/physiopathology , Age Factors , Blindness/physiopathology , Humans , InfantABSTRACT
Spasm of the near reflex is characterized by transient attacks of convergence, accommodation, and miosis. It is usually observed in young individuals and considered functional. We studied seven patients with spasm of the near reflex who had associated neurologic disorders or head trauma. Two patients had posterior fossa abnormalities (cerebellar tumor, Arnold-Chiari malformation), two patients had pituitary tumors, one patient had a vestibulopathy, and two patients had a history of antecedent head trauma.
Subject(s)
Ophthalmoplegia/diagnosis , Reflex, Abnormal/diagnosis , Accommodation, Ocular , Adolescent , Adult , Child , Convergence, Ocular , Female , Humans , Male , Middle Aged , Ophthalmoplegia/etiology , Ophthalmoplegia/physiopathology , Pupil , Reflex, Abnormal/etiology , Reflex, Abnormal/physiopathology , Spasm/diagnosis , Spasm/etiology , Spasm/physiopathologyABSTRACT
Amaurosis fugax followed by retinal infarction occurred as an early manifestation of exacerbation in a 46-year-old woman with allergic angiitis and granulomatosis (Churg-Strauss syndrome). There was evidence of widespread intraluminal branch retinal artery occlusions without accompanying retinal vasculitis. Low molecular weight dextran and heparin, in addition to systemic steroid therapy, appeared to be beneficial. A review of the ophthalmic manifestations of the Churg-Strauss syndrome and of other hypereosinophilic conditions suggests that thromboembolism resulting from a hypercoagulable state may be as important as vasculitis in causing visual symptoms. Specific therapy attempting to alter blood coagulation and rheology may have an important role in these conditions.
