Congenital cataracts in a child under 6 years of age can lead to profound visual impairment; the same cataract arising in a child over 6 years of age usually carries lesser consequences. The cause of this type of visual impairment is any prolonged obstruction of one eye, such as drooping of the upper eyelid occurring in infancy or early childhood. As an iatrogenic form of deprivation vision loss, obstructive vision loss may occur due to excessive therapeutic obstruction of the eye.

Treatment of deprivation of vision depends on the underlying factor. The time of susceptibility to treatment is when the visual impairment is reversible. This period of time in deprivation visually impairment lasts from a few weeks to a few months. In strabismic visually impaired up to about 9 years of age and in anisometropic visually impaired up to 11-12 years of age.

In strabismic deprivation the use of the worse eye is enforced by limiting the use of the better eye. The strongest treatment is therefore to cover the healthy eye during the entire waking hours, with an hour's break, or to partially cover it for about 1-6 hours a day. A practical rule of thumb is often used to determine the length of obturation depending on the age of the child. For example, a 6 month old child should be covered for 3 days, a 1 year old for 1 week, a 2 year old for 2 weeks and so on. If there is no improvement, the obstruction period can be doubled. Obturators glued to the skin, curtains attached to glasses or special contact lenses are used to cover the eye. The depth of vision loss is taken into account when determining how long the veil should be worn. For moderate to severe visual impairment, a minimum veiling time of six hours is recommended.

When using any obturation, the child does not need to do any special visual exercises, but should be kept as active as possible. The younger the child, the faster the improvement in visual acuity. Frequent follow-up visits are necessary to ensure that the initially better-sighted eye does not develop a visual impairment. This is even more dangerous the younger the child receiving obstruction and when it is used throughout the waking hours.

It is practical to follow a pattern of follow-up visits as follows: first follow-up visit one week after the start of treatment in infants, and in older children after an interval corresponding to one week for each year of life (e.g. for a 3-year-old child 3 weeks, for a 4-year-old child 4 weeks, etc.). In some cases of obstructive use, there is no response to the treatment given. This most commonly occurs in children over 5 years of age, occasionally in younger children. If there is no improvement in visual acuity within 3-6 months, the advisability of further obturation should be considered.

Thelength of use of obturation is an individual thing, but it is stated that the better the initial visual acuity, the shorter the time of necessary treatment may be. Consideration of surgical treatment for strabismus should take place once the visual impairment has been overcome and the process of restoring binocular vision has begun. Surgery involves weakening muscles that work too hard and strengthening muscles that work too weak.