PURPOSE. To study deactivation of the rod photoresponse in infants using a paired-flash procedure. Rhodopsin content increases and scales the parameters of the activation of rod phototrans duction as rods develop. How...PURPOSE. To study deactivation of the rod photoresponse in infants using a paired-flash procedure. Rhodopsin content increases and scales the parameters of the activation of rod phototrans duction as rods develop. However, little is known about the kinetics of deactivation in the rods of young infants. METHODS. ERG responses to pairs of flashes were used to study the recovery of the rod response in 4- and 10- week-old infants and mature control subjects. The amplitudes of rod isolated a-wave responses to a probe flash (+ 3.3 log scot tds) presented 2 to 120 seconds after an equal-intensity test flash were measured. The interstimulus interval (ISI) at which the amplitude was half that of the response to the probe flash alone (t50) was determined by linear interpolation. RESULTS. Recovery time (t50) was significantly longer in infants than in adults (F=18.9, df 2, 32; P<0.01). The shape of the recovery function did not vary with age. The t50 values were inversely proportional to the parameters of activation of rod phototransduction. CONCLUSIONS. These results are evidence that the kinetics of deactivation in infants are slower and may be set by the proportion of rhodopsin isomerized.展开更多
Background: To obtain a driver’s licence certain requirements for visual acui ty and visual field have to be fulfilled. Mesopic contrast and glare sensitivity are not regularly tested and are not crucial to passing t...Background: To obtain a driver’s licence certain requirements for visual acui ty and visual field have to be fulfilled. Mesopic contrast and glare sensitivity are not regularly tested and are not crucial to passing the driving test. Case report: We report a case of a 39-year-old professional bus driver whose only c omplaint was increased glare sensitivity. After he had been involved in four tra ffic accidents, ophthalmological investigations revealed binocular annular scoto mata and night blindness, leading to the diagnosis of rod-cone dystrophy. Discu ssion: Enhanced glare sensitivity is a common complaint in elderly people or peo ple with the beginnings of cataract but may also represent an initial symptom of a retinal disorder. It is therefore advisable for traf-fic safety if drivers w ith such complaints undergo a complete ophthalmological investigation including visual field testing.展开更多
文摘PURPOSE. To study deactivation of the rod photoresponse in infants using a paired-flash procedure. Rhodopsin content increases and scales the parameters of the activation of rod phototrans duction as rods develop. However, little is known about the kinetics of deactivation in the rods of young infants. METHODS. ERG responses to pairs of flashes were used to study the recovery of the rod response in 4- and 10- week-old infants and mature control subjects. The amplitudes of rod isolated a-wave responses to a probe flash (+ 3.3 log scot tds) presented 2 to 120 seconds after an equal-intensity test flash were measured. The interstimulus interval (ISI) at which the amplitude was half that of the response to the probe flash alone (t50) was determined by linear interpolation. RESULTS. Recovery time (t50) was significantly longer in infants than in adults (F=18.9, df 2, 32; P<0.01). The shape of the recovery function did not vary with age. The t50 values were inversely proportional to the parameters of activation of rod phototransduction. CONCLUSIONS. These results are evidence that the kinetics of deactivation in infants are slower and may be set by the proportion of rhodopsin isomerized.
文摘Background: To obtain a driver’s licence certain requirements for visual acui ty and visual field have to be fulfilled. Mesopic contrast and glare sensitivity are not regularly tested and are not crucial to passing the driving test. Case report: We report a case of a 39-year-old professional bus driver whose only c omplaint was increased glare sensitivity. After he had been involved in four tra ffic accidents, ophthalmological investigations revealed binocular annular scoto mata and night blindness, leading to the diagnosis of rod-cone dystrophy. Discu ssion: Enhanced glare sensitivity is a common complaint in elderly people or peo ple with the beginnings of cataract but may also represent an initial symptom of a retinal disorder. It is therefore advisable for traf-fic safety if drivers w ith such complaints undergo a complete ophthalmological investigation including visual field testing.
