I have just examined a patient who wears rigid gas permeable contact lenses. I fitted this patient with lenses about four months ago. At that time they did not have any ptosis. Today she has a left eye upper lid ptosis of about 2 mm. She has noticed this and does not like the cosmetic appearance. What is going on?
I have come across this problem. One of my optometry colleagues worked with me in an eye hospital. She was a rigid gas permeable (RGP) contact lens wearer and had some new lenses. Two weeks later she noticed upper lid ptosis on her left eye. She had no other neurological signs-oculo-motility, eye alignment and pupil reactions were all normal. She and I, being recently qualified, had never heard of the link between wearing RGP contact lenses and upper lid ptosis. The more experienced optometrists in the team immediately made the correction. She was examined by one of the ophthalmologists who confirmed the diagnosis.
The following ideas on potential causes have been put forward:
- Simultaneous, antagonistic action of the orbicularis and levator muscle while squeezing the eyelids to remove the lens
- Forceful rubbing of the lens and subsequent stretching of upper eyelid structures during failed attempts at lens removal
- Repeated and similar although less forceful rubbing of the lens during blinking
- Irritation, leading to oedema
- Irritation leading to blepharospasm.
In some cases, it seems that the chronic manipulation of the upper lid during rigid lens removal is responsible for inducing an aponeurotic disinsertion, which has been verified at surgery. There is a thinning and disinsertion of the levator aponeurosis. The aponeurosis is a fibrous membrane that covers certain muscles or connects them to their origins or insertions. The fibrous membrane which connects the levator muscle in the upper eyelid becomes thin and/or disconnected from its origin. This results in a reduction in the strength of the muscle and the upper lid droops.
In some reports, people who had successfully worn RGP lenses for many years suddenly developed ptosis. In some cases, lid surgery is required to correct the ptosis. In other cases refitting with an RGP lens with more curvature or a greater diameter or a soft contact lens or changing the removal technique-perhaps using a sucker.
In my colleague’s case after not wearing RGPs for two months, the ptosis spontaneously resolved within a few weeks. She was then fitted with RGP lenses of different parameters to the originals. We decided that this temporary ptosis was due to lid oedema resulting from the mechanical effects of the lens edge.