Drooping upper lids (ptosis)
The term ptosis in ophthalmology refers to a dropping of the upper eyelid, such that the opening of the eye is narrow. A unilateral ptosis means only one side is affected and when both upper eyelids are droopy it is called a bilateral ptosis. This is predominantly a condition which affects adults but rarely ptosis can be congenital, usually due to the levator muscle (which lifts the eyelid) failing to develop properly.
The most common cause in adults is an aponeurosis ptosis whereby the levator muscle attachment to the eyelid wears out. This results in the muscle stretching further away from the eyelid and therefore having less pulling power to raise the lid. This can occur in an ageing eyelid or in a younger person who has worn contact lenses for many years. Other causes of ptosis include lumps and bumps weighing down the upper lid, eyelid tumours and trauma. Rare neuromuscular diseases such as myasthenia gravis, chronic external ophthalmoplegia and myotonic dystrophy can also result in ptotic eyelids.
Symptoms of ptosis vary widely depending on the extent of the lid drop. In young children ptosis can be a serious issue as a droopy eyelid may prevent normal vision developing in the affected eye. Reduced eyesight from a congenital ptosis is called occlusion amblyopia. Adults with a mild ptosis may not have any symptoms but often people will be aware that they cannot see very well in the upper part of their vision, something that is usually worse at the end of the day when tired. In severe cases people struggle to see straight ahead without tilting their head back or holding the eyelids open with their fingers. Even mild ptosis can make an eye look "sleepy" which may be socially embarrassing and represent a cosmetic issue.
All cases of ptosis, even if asymptomatic, require a thorough assessment to establish a cause. This would include a full eye examination in children and adults.
The mainstay of ptosis treatment is surgery, although some of the rare neuromuscular diseases may be improved with medical therapy. Surgery generally involves reattaching or tightening the levator muscle to elevate the lid, most commonly by an anterior approach through a small crease in the upper eyelid skin under local anaesthetic. This can also be achieved through the back of the eyelid via a posterior incision in the conjunctiva (tissue which lines the eye surface and insides of the eyelids). The posterior approach is not suitable for all cases and in some circumstances may be contraindicated eg contact lens wearers. Any loose eyelid skin or bulging orbital fat can usually be removed (known as a Blepharoplasty) at the same time using either the anterior or posterior technique.
Overall the success rate of elevating a ptotic eyelid is high but there can often be a slight difference in height and contour (shape) symmetry between the two upper eyelids. Occasionally more than one operation is required to achieve a satisfactory result.
In situations where the levator muscle has not developed properly (in a congenital ptosis) or is severely weakened in an adult then the surgical treatment is different and involves performing a Brow Suspension. This involves connecting the eyelid to the forehead muscle which lifts the eyebrow. Either an artificial material eg nylon, silicone is used to make the link or a strong band of connective tissue (fascia lata) which is taken from the leg using a small incision just above the knee.