What is adult strabismus (squints)?

Strabismus (commonly known as squints) is a condition in which the eyeballs are not aligned properly and point in different directions. When it occurs in adults, it is called adult strabismus. Nearly four in every 100 adults have this condition.

What causes squints in adults?

Most adults with squints have had the condition since childhood. However, strabismus can also begin in adulthood due to medical problems, such as:

• Diabetes
• Thyroid disease (Graves’ disease)
• Myasthenia gravis
• Brain tumours
• Head trauma
• Strokes.

Occasionally, misalignment of the eyes can also occur after surgery on or around the eye, such as cataract surgery or retinal surgery. This is due to damage to the eye muscles during surgery.

What are the symptoms of squints?

Adults with squints may experience:

• Eye fatigue
• Double vision
• Overlapped or blurred images
• A pulling sensation around the eyes
• Reading difficulty
• Loss of depth perception.

To correct the inability to focus properly, many adults with squints have to tilt or turn their heads when focusing. They are also unable to make direct eye contact with both eyes when looking at people, which can make social situations awkward.

These symptoms may have a negative impact on employment and social opportunities.

How are squints in adults treated?

Squints in adults can be treated using several methods, including:

• Eye muscle exercises
• Glasses containing prisms
• Eye muscle surgery

Eye muscle exercises: Muscle exercises can be helpful in treating a form of squints in adults in which the eyes cannot align themselves for close work or reading. This condition is called convergence insufficiency.

Close work requires you to focus both eyes inward on close objects such as books, a needle and thread, computer screens. The coordinated movement and inward focusing of the eyes is called convergence. Dr Shuan Dai can provide advice about home eye muscle exercises to help retrain the eyes to focus inward together. However, eye muscle exercises are rarely useful in other cases of squints in adults.

Prism eye glasses: Eye glasses with prisms can correct mild double vision associated with squints in adults. A prism is a clear, wedge-shaped lens that bends, or refracts, light rays. When worn by an adult with squints who has mild double vision, the prism eye glasses realign images together so that the eyes see only one image. The prisms can be worn on the outside of the eye glass frames or can be manufactured directly into the lens itself.

Prism eye glasses usually cannot correct more severe cases of double vision where images are far apart or double vision caused by weak or tight muscles.

Eye muscle surgery: Eye muscle surgery is the most common treatment for squints. Typically, squints occur when the muscles surrounding the eyes are either too stiff or too weak. Eye Doctors squint specialist Dr Shuan Dai can surgically loosen, tighten or reposition selected eye muscles so that the eyes can be rebalanced to work together.

Surgery can:

• Improve eye alignment
• Reduce or eliminate double vision
• Improve or restore the use of both eyes together (binocular visual function)
• Reduce eye fatigue
• Expand peripheral (side) vision
• Improve social and professional opportunities.

Squint surgery is usually performed on an outpatient basis using general or local anaesthesia. Patients may experience some pain or discomfort after surgery, but it is usually not severe and can be treated with over-the-counter pain medication such as Panadol or paracetamol. Stronger medications for pain, such as codeine or hydroquinone, are sometimes needed and will be prescribed by your ophthalmologist or anaesthetist. You can often return to your normal activities within a few days.

More than one surgery may be needed to treat this condition depending on the severity of the case.

Patient pre-op, notice the left eye is not straight.

Patient post-op, notice that both eyes are now straight.

Adjustable sutures (stitches) surgery

To obtain more precise alignment of your eyes, Dr Shuan Dai may use adjustable sutures (stitches). This allows your eye alignment to be adjusted after surgery. If adjustable sutures are used, surgery is performed in two stages.

Stage one involves repositioning one or more of the eye muscles with “slipknot” or “bow-tie” sutures. In stage two (usually performed immediately after you wake up from general anaesthesia), using anaesthetic eye-drops, the sutures are untied and retied to fine-tune the alignment. In many cases, no adjustment is needed and the slip knot or bow-tie sutures are converted to standard knots.

What are the risks of squint surgery?

Vision loss from squint surgery is extremely rare. However, as with all surgeries, there are risks to consider. Complications can include:

• Allergic reaction to the anaesthesia
• Infection
• Reduced vision, often temporary 
• Double vision within the first week or two after surgery, long lasting double vision is very rare
• Inadequate eye alignment.

It is never too late to treat squints.

Adults do not need to live with the discomfort and problems caused by misaligned eyes. Surgery with Dr Shuan Dai, and/or a combination of other treatment methods, can improve the symptoms associated with squints.