This is an interesting, masked, prospective study examining the hypothesis that increased upper eyelid laxity in normal patients may be related to the side on which they usually sleep. Two hundred and sixty-two normal subjects, over 55 years old, had their upper lid laxity measured and were asked by a separate researcher which side they usually slept on. Of that 70% were found to have significantly greater laxity on their sleeping side, with mean measurements of 6.1mm on the sleeping side compared with 4.9mm on the non-sleeping side. Although this association is known in floppy eyelid syndrome related to obstructive sleep apnoea, it has not previously been assessed in normal subjects. The authors suggest the pathogenesis is due to mechanical tissue stress and its effect on disrupting tensional homeostasis at a cellular level. They also speculate this phenomenon may also play a role in the pathogenesis of ptosis, ectropion, entropion and dermatochalasis. They note that sleep side preference has been associated with asymmetrical progression in glaucoma, and that ocular circulation may also be compromised with an increased risk of nonarteritic anterior ischaemic optic neuropathy. However, they do not explore the possibility that pressure leading to hypoperfusion may be the cause of increased lid laxity in normals. This is an interesting paper with strong data from a simple, masked, prospective study with statistically significant results. It raises many more questions regarding the pathogenesis of floppy eyelid syndrome, especially over the relative importance of mechanical versus hypoxic factors.
Sleep side preference affecting lid laxity in normal subjects
Reviewed by James Hsuan
LESCs: Lateralizing eyelid sleep compression study.
