There are many long-term corneal GP lens wearers who have significant blepharoptosis (Figure 1). Whether the lenses caused the condition, exacerbated it, or had nothing to do with it at all is a somewhat difficult question to answer. Multiple studies have been done, though, suggesting that GP lens wear may be to blame (Hwang and Kim, 2015; Kitazawa, 2013). Even today, GP lens wear often begins at a young age to treat keratoconus (especially when diagnosed during the teen years) or for orthokeratology in young myopes (as a tool for myopia control). When soft lens alternatives exist, it is unclear whether the risk of blepharoptosis is enough to warrant elimination of GP lens options—particularly because there may also be a risk of blepharoptosis, albeit lesser, with soft lenses (Bleyen et al, 2011).

Possible Mechanisms

Multiple mechanisms have been suggested for GP lens-induced ptosis. For example, lens removal techniques that involve eyelid pulling or stretching may contribute to this condition (Thean and McNab, 2004). Luckily, lens removal devices/plungers are viable alternatives to these techniques. Patients should be instructed on the use of those alternatives along with traditional removal techniques, which are still important to know in case removal devices are unavailable.

Additionally, fitting properties—such as lid attachment with persistent lens weight and pull resulting in lower lid positioning and stretching stress on the levator aponeurosis and/or fibrosis of Müeller’s muscle—might also play a role in blepharoptosis development (Watanabe et al, 2006). This may be less worrisome in patients fit with orthokeratology, as they generally do not wear their lenses upright with open eyelids.

Evidence to the Contrary

Recent research on Chinese eyes may refute many of these theories. Of 90 daytime GP lens wearers and 45 orthokeratology wearers—compared to 45 spectacle-wearing controls—none were shown to have enough changes in lid properties to be diagnosed with ptosis (Yang et al, 2019). However, there were still some significant differences between daytime GP lens wearers and orthokeratology users, with less change in marginal reflex difference and palpebral fissure height in the orthokeratology group (Yang et al, 2019).

Conversely, it has been reported that scleral GP lenses can be used to successfully improve blepharoptosis resulting from various etiologies including corneal GP lens wear and other non-lens-related pathologies. For instance, using the scleral lens to “bulk up” the ocular surface can increase objective measurements of palpebral aperture size and upper margin-reflex distance (Shah-Desai et al, 2011) as well as subjective appearance (Katsoulos et al, 2018).

In Conclusion

While the benefits of appropriately fit corneal GP lenses generally far outweigh this possible risk, blepharoptosis should be considered a potentially serious side effect. This is particularly true considering that the primary treatment of blepharoptosis is surgical intervention. Interestingly, if scleral lenses may be a beneficial treatment for blepharoptosis, perhaps it can be said even more emphatically that more good than harm comes from fitting GP lenses. CLS

For references, please visit www.clspectrum.com/references and click on document #289.