PURPOSE: The pupil light reflex is considered to be a simple subcortical reflex. However, many studies have proven that patients with isolated occipital lesions with homonymous hemianopia show pupillary hemihypokinesia. Our hypothesis is that the afferent pupillary system consists of two pathways: one via intrinsically photosensitive retinal ganglion cells (ipRGCs), the other running through the normal RGCs via the visual cortex. The purpose of this study was to test the hypothesis of these two separate pupillomotor pathways. METHODS: 12 patients (59.1 ± 18.8 years) with homonymous hemianopia due to post-geniculate lesions of the visual pathway and 20 normal controls (58.6 ± 12.9 years) were examined using chromatic pupillography: stimulus intensity was 28 lx corneal illumination, stimulus duration was 4.0 s, and the stimulus wavelengths were 420 ± 20 nm (blue) and 605 ± 20 nm (red), respectively. The examined parameters were baseline pupil diameter, latency, and relative amplitudes (absolute amplitudes compared to baseline), measured at maximal constriction, at 3 s after stimulus onset, at stimulus offset, and at 3 s and 7 s after stimulus offset. RESULTS: The relative amplitudes for the red stimulus were significantly smaller for hemianopia patients compared to the normal controls [maximal constriction: 35.6 ± 5.9% (hemianopia) to 42.3 ± 5.7% (normal); p = 0.004; 3 s after stimulus onset: p = 0.004; stimulus offset: p = 0.001]. No significant differences in any parameter were found between the two groups using the blue stimulus. CONCLUSIONS: The results support the hypothesis that the ipRGC pathway is mainly subcortical, whereas a second, non-ipRGC pathway via the occipital cortex exists.

• Klíčová slova
• Dorsal midbrain, Homonymous hemianopia, Intrinsically photosensitive retinal ganglion cells, Pupil light reflex, Pupillary hemihypokinesia, Visual cortex,
• MeSH
• diagnostické techniky oftalmologické * MeSH
• dospělí MeSH
• hemianopsie diagnóza   etiologie   patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mezencefalon diagnostické zobrazování   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• nemoci mozku komplikace   diagnóza   MeSH
• počítačová rentgenová tomografie MeSH
• pupila fyziologie   MeSH
• reflex pupilární fyziologie   MeSH
• reprodukovatelnost výsledků MeSH
• retinální gangliové buňky fyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• světelná stimulace MeSH
• zraková pole fyziologie   MeSH
• zrakové korové centrum diagnostické zobrazování   patofyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: To ascertain whether the pupillary response amplitude shows spatial summation of responses with increasing size of retinal stimulation, and to examine the pupillary responses for evidence of surround inhibition, analogous to that found in the receptive fields of the retinal ganglion cells. METHODS: By means of infrared-video-pupillography, the pupil reaction to stimuli of increasing size (1-15°) was measured in 30 normal subjects. Four different retinal locations (0°, 20° and 40° eccentricity on the upper temporal retina and 20° eccentricity on the lower nasal retina) were examined at four different stimulus luminances (17, 47, 87 and 140 cd/m(2)). RESULTS: When the average log amplitude of the pupil light reaction from the 30 subjects is plotted as a function of the log area of the stimulus, a bi-linear response is observed, which is most pronounced for the two higher luminances. The intersection points of the two linear responses are 2.01° in the fovea, 2.80° at 20° upper temporal retina, 2.85° at 20° lower nasal retina and 4.86° at 40° upper temporal retina. CONCLUSIONS: This study suggests that pupillomotor summation areas consist of both summation and inhibitory zones. They show larger diameters than receptive fields of retinal ganglion cells and do not appear to reflect pupillary summation areas of the pretectal olivary nucleus luminance neurons.

• MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• nitrooční tlak fyziologie   MeSH
• pupila účinky záření   MeSH
• reflex pupilární fyziologie   MeSH
• retina fyziologie   MeSH
• světelná stimulace MeSH
• testy zrakového pole * MeSH
• zraková ostrost fyziologie   MeSH
• zraková pole fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH