Eye deviation (Strabismus)

Strabismus, often called "squint," is a condition where the eyes do not align properly. One eye turns in, out, up, or down while the other eye looks straight ahead. This misalignment prevents the eyes from working together as a team, which can affect depth perception and may lead the brain to ignore the image from the turned eye (causing amblyopia).

Disease

Symptoms

The most obvious sign is an eye that is visibly misaligned. In children, you might also notice squinting, tilting the head, or closing one eye. Adults with new-onset strabismus often experience double vision (diplopia). Risk factors include family history, uncorrected refractive error, certain neurological conditions, and thyroid eye disease (in adults).

Diagnosis

An eye doctor will assess eye alignment using various tests, such as observing light reflexes on the cornea or having the patient look at a target while covering and uncovering each eye to see how they move. Sensory and motor tests of strabismus must be done by a professional ophthalmologist.

Treatments

The goal is to straighten the eyes so they can work together. Treatment options include: prescription glasses (especially if caused by a focusing problem), prism lenses to reduce double vision, or surgery (most common) on the eye muscles to adjust their position and strength.

More to read

Disease

Cataract

A cataract is a clouding of the eye's natural, clear lens. Think of it as a clear window that slowly becomes frosted. This clouding scatters light, preventing a sharp image from reaching the retina. It is most commonly related to aging. However, some forms of congenital cataract are seen in children.

Disease

Refractive Error

Refractive error means that your eye does not focus light ideally onto the retina, resulting in a blurred image on the retina. This condition is not a disease, but a common problem with light focusing. Its main types include myopia (nearsightedness: nearby objects are clear while distant objects appear blurry), hyperopia (farsightedness: distance vision may be clearer than near vision), and astigmatism (vision is blurry at all distances due to an irregularly shaped cornea).

Disease

Night Blindness

Night blindness is a symptom, not a disease. It means your eyes have trouble adapting to low light. This is often due to a problem with the rod cells in your retina, which are responsible for night and peripheral vision.

Disease

Color Blindness

Most color blindness is not complete blindness to color, but a difficulty telling certain colors apart. It is usually an inherited condition (more common in males) present from birth. It happens when certain light-sensitive cone cells in your retina don't work properly. The most common type is trouble distinguishing reds from greens.

Disease

Retinopathy of Prematurity

ROP is a disease that affects premature infants. In the womb, the retinal blood vessels grow late in pregnancy. When a baby is born very early, this normal growth is interrupted. After birth, abnormal, fragile blood vessels may begin to grow in the retina. These vessels can leak and scar, potentially pulling the retina off (detachment).

Disease

Retinal Detachment

A retinal detachment is a medical emergency. It occurs when the retina peels away from the back wall of the eye, like wallpaper bubbling off a wall. When detached, the retina cannot function, leading to vision loss.