night blindness
Introduction
Introduction The sensitivity to low light is reduced, and the dark adaptation time is prolonged. The main symptom is that the daytime vision is almost normal, and when the light is dim at dusk, the vision is unclear. In the night or in the dark, the object is unknown, the white spot or the light is as usual, and the eye appearance is good as the main eye disease.
Cause
Cause
The cause of night blindness:
The root cause of night blindness is that the retinal rod cells lack the raw material for synthesizing rhodopsin or the lesion of the rod cells themselves.
(l) Temporary night blindness. Due to the lack of vitamin A in the diet or the absorption of vitamin A due to certain digestive diseases, the retinal rod cells do not have the synthetic rhodopsin material and cause night blindness. This night blindness is temporary. As long as you eat more pig liver, carrots, cod liver oil, etc., you can supplement the deficiency of vitamin A and will soon heal.
(2) Acquired night blindness. Often caused by malnutrition of the retinal rod cells or its own pathology. Common in diffuse choroiditis, extensive choroidal ischemia and atrophy, such night blindness gradually improved with effective treatment and disease healing.
(3) Congenital night blindness. It is a congenital hereditary eye disease, such as retinitis pigmentosa, rod cell dysplasia, loss of the function of synthesizing rhodopsin, so night blindness occurs.
Although night blindness is often caused by the lack of VitA, the supplement of VitA must be carried out under the guidance of a doctor. Excessive use may cause VitA poisoning.
In order to prevent night blindness, it is common to eat more vegetables and fruits. If you can't eat vegetables and fruits in special circumstances, you should eat vitamin A tablets properly.
Examine
an examination
Related inspection
Dark adaptation curve photodetection
1. Consult your medical history, such as diet, fever, and long-term diarrhea.
2, check the conjunctiva, corneal conditions, pay attention to the presence or absence of conjunctival dryness, wrinkles, Bitot spots, corneal opacity, softening or perforation.
3, to identify the reasons for the reduction of dark adaptation and the cause of dry eye, if necessary, dark adaptation and electroretinogram.
4. Check for systemic vitamin A deficiency and other vitamin deficiency symptoms.
Diagnosis
Differential diagnosis
Night blind confusing symptoms
Blindness: refers to an anomalous phenomenon in which the vision is worse than when the light is dim in a brightly lit environment. A diagnosis can be made based on medical history and eye examination.
Partial hemianism: Medical terminology refers to the partial diagnosis of a part of the visual field. The hemianopia caused by visual pathological lesions often contributes to the localization diagnosis of neuropathy. When the optic chiasm is oppressed by the tumor, it often causes typical bilateral hemianopia. Some ophthalmic diseases can also cause hemianopia-type visual field defects, such as nasal visual field defects in advanced glaucoma, blunt-type visual field defects in retinal vascular occlusion, and visual field defects in the opposite direction when the retina is partially detached.
Quadrant defect: also known as quadrant hemianopia, that is, the visual field defect occupies a quadrant, more common in visual path damage above the optic chiasm.
Cortical blindness: A central visual dysfunction caused by toxins or vasospasm in the occipital cortex of the brain, with vasospasm being the most common. The clinical manifestations are complete loss of binocular vision, normal pupillary light reflex, normal fundus, and hemiplegia.
Diagnosis can be made by measuring visual acuity in low light.
