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Eyelid Ptosis
Contact lens practitioners routinely examine the tarsal conjunctiva and lid margins of their patients, but little attention is generally given to the overall integrity of the eyelids. Eyelid dysfunction, whether caused by contact lens wear or other factors, can pose a problem for contact lens wearers because this could interfere with some of the important roles played by the eyelids.
This chapter will concentrate on a condition that is often overlooked by eye care practitioners – contact lens–induced ptosis (CLIP) of the eyelids. Ptosis is defined as ‘prolapse, abnormal depression, or falling down of an organ or part; applied especially to drooping of the upper eyelid’. Because ptosis is not confined to the eyelids, some authors prefer to use the more exact term ‘blepharoptosis’. An assortment of other eyelid disorders that may be of relevance to contact lens wear will also be considered.
CLIP is perhaps the only complication of contact lens wear for which surgical intervention is contemplated and occasionally executed (notwithstanding infectious keratitis associated with corneal ulceration, which sometimes requires hospitalisation and can result in keratoplasty). It is for this reason that clinicians should have an appreciation of the typical manifestation of this condition, its likely causation, indications for surgery and other management options.
Signs
The classic appearance of ptosis is of narrowing of the palpebral fissure and a relatively large gap between the upper lid margin and the skin fold at the top of the eyelid ( Fig. 6.1 ). In a normal individual without ptosis, the skin fold at the top of the eyelid is only slightly higher than the upper eyelid margin. In some patients, these anatomical features can become virtually coaligned toward the outer canthus.
It is possible to detect CLIP if (1) a patient reports that he or she detects narrowing of the palpebral apertures; (2) palpebral aperture height is measured accurately on many occasions over time (to detect a trend); or (3) one eye is affected more than another. Because contact lenses are typically worn in both eyes, any contact lens–induced narrowing of the palpebral apertures will be expected to be bilateral. However, Kersten et al. reported CLIP to be unilateral in 58% of a series of presenting patients. Unilateral CLIP can arise as a result of lens handling-related trauma, whereby the patient is more forceful with lens insertion or removal on either the right or the left side. Unilateral CLIP can also result from uniocular lens wear or the highly unusual scenario of wearing of a different lens type in each eye of (i.e. rigid lens in one eye and soft lens in the other eye).
Fonn and Holden conducted a longitudinal trial designed to compare the ocular response to rigid and hydrogel contact lenses worn for an extended period. The experimental protocol called for inter-ocular comparison; that is, a rigid lens was worn in one eye and a hydrogel lens was worn in the other eye. It was observed that the palpebral aperture of the eye wearing the rigid lens was noticeably narrower than that in the eye fitted with the soft lens in 77% of the 40 subjects who participated in the trial ( Fig. 6.1 ).
Severity
Various studies have quantified the extent of palpebral aperture closure resulting from various modalities of contact lens wear. Fonn et al. measured the palpebral aperture size to be 10.10 ± 1.11 mm in non-wearers, 10.24 ± 0.94 mm in soft lens wearers and 9.76 ± 0.99 mm in rigid lens wearers. The difference in palpebral aperture size between the rigid lens wearers and the soft lens wearers (0.48 mm) and between the rigid lens wearers and the non–lens wearers (0.34 mm) was statistically significant, but there was no significant difference in palpebral aperture size between soft lens wearers and non-wearers (0.14 mm). The rigid lens wearers had been wearing lenses for 11.6 ± 8.4 years, and the soft lens wearers had been wearing lenses for 8.2 ± 5.5 years. No gender difference in the development of CLIP was noted.
Satariano et al. determined that the mean ptosis measurement was 1.00 mm among those who did not wear contact lenses, 1.41 mm among those who wore soft contact lenses and 1.84 mm among those who wore rigid contact lenses.
A study by van den Bosch and Lemij, similar to that described earlier, found that the upper lid had lowered by 0.5 mm in a group of patients who had been wearing rigid lenses for an average of 16.3 years. The reason for a greater amount of ptosis in this study (vs. that of Fonn et al. ) may be attributed to the greater lens wearing experience of the subjects examined (16.3 vs. 11.6 years), although Fonn et al. noted no such relationship within their own study group. The position of the lower lid was unaltered by rigid lens wear.
Reddy et al. reported mild to moderate bilateral CLIP in nine soft lens wearers with a mean age of 24.2 years (range 15–35 years). All had been wearing soft contact lenses for at least 2 years before presentation, with a mean exposure of 5.6 years. None of the lens wearers had papillary conjunctivitis, which can also induce CLIP.
Time course of onset
Fonn and Holden monitored the time course of onset of CLIP in 17 subjects who wore a soft lens in one eye and a rigid lens in the other. In the eye wearing the rigid lens, maximum ptosis (12% closure) was observed between 4 and 6 weeks after commencing lens wear; this was followed by a relative lessening of the ptosis to a point where the palpebral aperture size was 3% smaller compared with baseline after 13 weeks ( Fig. 6.2 ). The palpebral aperture size remained fairly stable in the eye wearing the soft lens for the first 7 weeks but, paradoxically, began to increase thereafter to become 7% wider compared with baseline after 13 weeks. (Apparent widening of the palpebral aperture as a result of soft lens wear is discussed later in this chapter).
In the longer term, the pattern of onset can be variable. In one study, all but 2 of 17 patients presenting to a clinic complaining of CLIP reported that the condition had developed gradually over the past 12 to 24 months; most of these patients could illustrate this with photographs. The other two patients in this study noted that the ptosis had existed for 6 and 16 years, respectively, and had gradually become worse.
Symptoms
Based on their observation of 17 patients presenting to a clinic complaining of advanced CLIP, van den Bosch and Lemij demonstrated that ‘generally’ this is a condition that will be noticed by patients. No associated signs or symptoms were noted in any of these patients.
It is also interesting that, in prospective studies of palpebral aperture height in asymptomatic contact lens wearers, none of the patients deemed to be suffering from CLIP were aware that they had this condition.
Prevalence
Rigid lenses
Ptosis is defined by van den Bosch and Lemij as a condition wherein the distance between the centre of the pupil and the lower margin of the upper lid is less than 2.8 mm. By using this criterion, these authors determined that the prevalence of ptosis in a consecutively presenting group of 46 rigid lens wearers was 11% versus 1% in a control group of non–lens wearers. Jupiter and Karesh reported the prevalence of ptosis in a population of rigid lens wearers to be 4.7%. Kersten et al. noted contact lens wear to be the only identifiable cause of acquired ptosis in 47% of a series of 91 patients who were 15 to 50 years of age and had this condition between 1986 and 1994.
Thean and McNab published a report of a total of 15 consecutive patients who presented over a 4-year period (1997–2001) with blepharoptosis in the context of prolonged contact lens use. Four of the 15 patients (27%) were wearing rigid gas-permeable lenses. The rest had been wearing polymethyl methacrylate (PMMA) lenses. Thirteen patients (87%) had been wearing their contact lenses for more than 17 years. The age of the patients ranged from 15 to 71 years (mean age 46 years). All 15 patients had normal levator palpebrae superioris function. Four patients (27%) had bilateral involvement.
Soft lenses
Reddy et al., who used the same definition of ptosis as that used by van den Bosch and Lemij, noted that although only 13% of all Americans wear soft contact lenses, the prevalence of soft contact lens use in their series of patients with acquired ptosis and no other clinically evident cause for ptosis, irrespective of age, was much higher at 52%. In their study, the prevalence of soft contact lens use in patients under age 35 years with unspecified acquired ptosis was 69%. They concluded that (1) soft contact lens use was approximately five times more common in young patients, who developed otherwise unexplained acquired ptosis than in the general population, and (2) soft lens wear was the most common risk factor for ptosis in patients under age 35 years.
Bleyen et al. reported on a consecutive retrospective series of 35 patients diagnosed with unilateral or bilateral ptosis. The history of contact lens wearing in these patients was as follows: 20 (57%) (ages 18–50 years; average 37 years) had been wearing hard contact lenses for, on average, 17.6 years (range 6–27 years); 9 (26%) (ages 18–45 years; average 30 years) had been wearing soft contact lenses for, on average, 9 years (range 1.5–20 years); and 6 (17%) (ages 23–39 years; average 33 years) had no history of contact lens wear. The odds ratio (OR) for soft contact lenses was 14.7 (95% confidence interval (CI) 4.2–50.7) and for hard contact lenses 97.8 (22.5–424). The authors concluded that not only hard contact lens wear but also soft contact lens wear may be associated with ptosis.
Risk factors
Hwang and Kim conducted a systematic review to evaluate the risk for blepharoptosis in contact lens wearers. In a PubMed search, 393 papers were found using the terms ‘lens and ptosis’. The abstracts were read, and 16 full-text articles were reviewed. Among them, five articles were analysed. Five studies were subgrouped and a meta-analysis of these data suggested that there is an increased risk for blepharoptosis in rigid lens wearers over non–lens wearers (n = 7426; OR 17.38; 95% CI 3.71–81.29; p < 0.00001). One study was sub-grouped, and these data suggested that there is also an increased risk for blepharoptosis in soft lens wearers over non–lens wearers (n = 90; OR 8.12; 95% CI 2.68–24.87; p < 0.0002).
An age-matched case-control study was performed by Kitazawa in a hospital in Japan. The rate of rigid lens use in ptosis cases was compared with that in a control group, and then the OR was estimated. A history of wearing rigid lenses was significantly higher in patients (90.2%) versus controls (31.6%). Rigid lens wearers had a 20 times increased risk for ptosis (OR 19.9; 95% CI 6.32–62.9) compared with non-lens-wearing subjects.
Satariano et al. assessed the environmental factors that may contribute to eyelid ptosis in a population of identical twins. Photographs of 286 sets of twins from a prospectively collected database from 2008 to 2010 were reviewed and digitally analysed; 96 sets of identical twins (192 individual persons) had differing severity of ptosis. Wearing either hard or soft lenses was associated with an increased risk for ptosis, and these influences are independent of genetic predisposition.
Watanabe et al. investigated the effect of myopia, duration of rigid contact lens wear and patient age on the progression of ptosis among 194 eyes of 98 patients with either bilateral or unilateral ptosis. The average best-sphere refractive error was − 8.34 diopter (D) in those with severe ptosis; − 6.28 D in those with moderate ptosis; − 5.57 D in those with mild ptosis; and − 4.80 D in those with no ptosis. The average duration of rigid lens wear was 34 years in those with severe ptosis, 30 years in those with moderate ptosis, 29 years in those with mild ptosis, and 31 years in those with no ptosis. The authors concluded that high myopia, patient age and long-term rigid lens wear are risk factors associated with the progression of ptosis.
de Silva and Collin observed that increased severity of ptosis was directly related to patient age and refractive error (p < 0.005), but not to the duration of contact lens wear.
Pathology
There is general agreement that the pathological basis of CLIP is either (1) oedema leading to lid swelling or (2) disinsertion, dehiscence (splitting), thinning or lengthening of the levator aponeurosis. The relatively large gap between the upper lid margin and the skin fold at the top of the eyelid described earlier (also referred to as a ‘high skin crease’) develops because the posterior fibres of the levator aponeurosis on the tarsal plate disinsert, split or lengthen, whereas the anterior insertion of the levator aponeurosis into the orbicularis muscle and skin remains intact. Thinning of the eyelid is also sometimes observed.
Aetiology
A number of mechanisms have been advanced as possible causes of CLIP. These can broadly be categorised into aponeurogenic (i.e. involving some form of dysfunction of the aponeurosis) and non-aponeurogenic causes.
Aponeurogenic causes of CLIP
Forced lid squeezing
The unnatural ‘forced blink’ rigid lens removal technique places simultaneous, but antagonistic, forces on the orbicularis and levator muscles. Because rigid lens wearers are instructed to open their eyes wide while executing a powerful blink, both the levator and orbicularis muscles are attempting to contract at the same time. The opposed actions of these two muscles might cause increased traction on the levator aponeurosis, leading to disinsertion or dehiscence.
Lateral eyelid stretching
To effect rigid lens removal, patients are often instructed to pull firmly on the outer canthus to create increased tension in the eyelids so that a greater leverage force is created to cause the lens to be blinked out of the eye. Although this action primarily may lead (if anything) to a disinsertion or dehiscence of the lateral canthal ligament or the medial canthal tendon, it should not by itself lead to a disinsertion or dehiscence from the levator aponeurosis. However, in combination with the antagonistic contraction of the orbicularis and levator muscles during forced blink removal, as described previously, stretching or thinning of the levator aponeurosis cannot be discounted.
Consideration of these two aetiological factors – forced lid squeezing and lateral eyelid stretching – leads to the disturbing conclusion that actions undertaken by both practitioners and patients may be responsible for CLIP in some cases. This conclusion is supported by the report of five cases of CLIP by Epstein and Putterman, who observed that two of these cases developed directly after the patients were fitted with rigid lenses. The ptosis in these two patients did not resolve after cessation of lens wear.
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