Diagnosis Of Amblyopia 1

Medical History Collection

It mainly includes: main complaint, general medical history, growth and development history, family history and medication history. Patients or their families may report poor vision in one or both eyes, difficulty in engaging in activities related to both eyes, incorrect eye position in photography or observation, like to cover or close one eye, etc.

Visual Examination

After many discussions in 2010 and 2011, according to the epidemiological characteristics and referring to the visual development status of children of different ages, the lower limit of normal vision of Chinese strabismus and Pediatric Ophthalmology Group is: the lower limit of normal vision of children aged 3 is 0.5, that of children aged 4-5 is 0.6, that of children aged 6-7 is 0.7, and that of children aged above 7 is 0.8 The best corrected visual acuity of two eyes differs by two lines or more, and the poor eye is amblyopia. If children's visual acuity is not lower than the lower limit of normal visual acuity of children of the same age, the difference of binocular visual acuity is less than two lines, and no risk factors causing amblyopia are found, they should not be hastily diagnosed as amblyopia and can be listed as the object of observation.

Children with amblyopia have no clear main complaint, and the prevalence of strabismus accounts for only 1 / 6. Most cases are found only by chance in visual examination, and early correction is the key factor for the prognosis of amblyopia, so early screening is very important for the discovery of amblyopia.

Infants < 2 years old

(1) Optokinetic Drum. 

When measuring, rotate the drum with grating. Infants and young children watching the rotating drum will cause nystagmus, and their visual acuity is calculated by the thinnest stripe that can cause nystagmus.

(2) Infant Selection Vision Card. 

Forced priority fixation card is suitable for visual acuity measurement of infants and young children. One side of the visual acuity chart used for measurement is black-and-white bar grid, and the other side is uniform gray. The bars are graded according to their thickness. The thicker the bar is, the easier it is to be observed. Studies have shown that children prefer to look at the side with the grid. The width between stripes of the grating can be changed to quantify vision.

In addition, teller vision card can also be used for infant vision measurement. 

Teller vision card is a vision chart with 17 cards invented by teller in 1997. The size of 17 cards is 25.5 × 55.5cm card, with a small hole of 4mm Diameter in the center of each card. The card has a gray background and bars on it. The frequency of bars in each card is different. According to different ages and visual impairment, there are different card frequency settings to choose from. It is generally recommended to test a full set of cards. If you roughly estimate your eyesight, you can also test half of the cards. Vision tests range from 0.05 to 1.0.

(3) Covering Method. 

When all examination methods cannot be carried out, the simplest and most effective method is to observe the reaction of infants and young children by covering method. When covering the eyes with better eyesight, it may show that the child will take off the cover with his hand or even cry, that is, the cover aversion test, while covering the eyes with poor eyesight will not.

(4) Visual Evoked Potential (VEP). 

The electrodes are placed in the occipital part and the mastoid process behind the ear, and the ground wire is connected to the forehead, so that the children can focus on the grid or grid visual target, and the visual response is transmitted to the center of the lateral knee through the optic omentum to generate visual evoked potential. When the VEP curve is traced by computer, the narrower the visual grid or bar grid, the higher the spatial frequency of the curve. The visual acuity can be converted according to the maximum spatial frequency.