This small prospective case-controlled study found that keratoconus patients have increased eyelid laxity, along with a more rubbery tarsus, which may be along the spectrum of floppy eyelid syndrome.
Additional results indicated that keratoconus patients had a high prevalence of obstructive sleep apnea and obesity. Although the association between floppy eyelid syndrome, obstructive sleep apnea and keratoconus has been previously demonstrated extensively in the literature, it continues to be an important reminder to ophthalmologists to screen for obstructive sleep apnea, which may increase morbidity and mortality in these patients.
The study included 15 adult keratoconus patients. They were matched for age, sex, race and body mass index with controls. Extensive eyelid laxity measurements were performed on both groups. Additionally, medical/ophthalmic history and Epworth Sleepiness Scales were completed on 50 keratoconus patients and compared with the normal population.
Compared to the control group, the keratoconus group showed significantly more vertical lid pull, lower lid pull, medial canthal tendon distraction, palpebral width and rubbery tarsus, and increased corneal diameter (P = 0.02) and increased exophthalmometry measurements (P = 0.01).
Also, the prevalence of obstructive sleep apnea (24 percent) in keratoconus patients was higher than the 4 to 5 percent prevalence in the general population and the zero percent rate in the control group. The obesity rate in keratoconus patients was 52 percent compared with the national prevalence of 33.8 percent.
The authors believe that an inflammatory process is the underlying cause of floppy eyelid syndrome and that this could explain the associations of floppy eyelid syndrome with keratoconus and also possibly obstructive sleep apnea and obesity.