Lifting the Lid on Eye Pressure

Intraocular pressure (IOP) is a delicate biometric – even a small increase heightens the risk of developing glaucoma, and risk only increases with age. We also know that rates of lid malposition increase with age, so it is much more likely that a patient requiring surgery for lid malposition is at risk of glaucoma. But how does surgery on the lower-lid affect the pressure of the eye?

Clinical researchers from the UK have investigated the effect of lower-lid surgery with the lateral tarsal strip (LTS) technique on IOP – finding that the surgery was associated with a statistically significant increase in IOP, both immediately and, in some patients, three months after surgery (1). Lead authors for this work, Harpreet Kaur and Sarj Athwal, explain that impact of this finding “a prolonged period of increased intraocular pressure due to lid tightening could result in poor control of glaucoma, resulting in disease progression.” They go on to explain the functional principle behind findings “Imagine holding an inflated beach ball in your hands. If you squeeze it and apply pressure on one end, you know that the external pressure has an effect on the internal pressure from the way the shape of the ball becomes distorted. We wanted to find out if the same thing happens to the eyeball when you tighten the eyelid against it by assessing whether the intraocular pressure changes.”

This work has emphasized the importance of considering a patient’s glaucoma when thinking about surgical options – it is possible that surgery could have detrimental effects on glaucoma risk and disease progression. Harpreet and Sarj highlight that “this is relevant not just to ophthalmologists, but all clinicians performing lid surgery for functional or aesthetic reasons such as plastic and maxillofacial surgeons.”

An important consideration of this paper is that the study was designed to look at lower-lid post-surgery changes in IOP for healthy eyes. The authors point out that, while this is important and useful research, “there is a need for further research to assess and quantify the risk in patients with pre-existing glaucoma.”