Sir,

Ocular massage is believed to be a simple procedure to reduce intraocular pressure (IOP). Ocular response analyser (ORA) is a non-contact tonometer that measures corneal hysteresis (CH) and corneal resistance factor (CRF).1 The ORA provides a corneal-compensated IOP (IOPcc), which is less affected by central corneal thickness (CCT).2 How much IOP can be reduced from ocular massage and how ocular massage affects corneal biomechanics?

Fifty-three young healthy adults (20–31 years) were recruited. This study was approved by the Ethics Committee of the institute. One eye was randomly selected and four measurements in accordance with the instruction manual were first taken using the ORA. Subjects were at rest for 10 min and another four measurements were taken again. Each subject then wore an eye massager (iCare 2000, OSIM International Ltd, Singapore) to receive ocular massage for 5 min. The vibration mode was set to the maximum level. Subjects were instructed to tilt the lower part of the eye massager slightly upwards to provide more direct pressure through the upper eyelid (Figure 1). Four final measurements were taken after the ocular massage. Table 1 lists the IOPcc, CH, and CRF results from the three sessions. Repeated measure analysis of variance, with post hoc test, demonstrated significantly lower IOPcc and higher CH after ocular massage. The CRF was significantly lower after ocular massage. The difference between the first and second sessions was not significant, indicating good repeatability. The change in IOPcc was independent of the initial IOPcc (correlation coefficient r=0.06, P=0.68), CH (r=0.06, P=0.67), and CRF (r=0.09, P=0.54). Figure 2 shows the distribution of the IOPcc change.

Figure 1
figure 1

The eye massager being worn with tilting of the lower part slightly upward for a more direct vibrating force through the upper eyelid.

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Table 1 Mean±SD of ORA measurements from the three sessions.
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Figure 2
figure 2

Distribution of change in IOPcc from ocular massage. Positive value indicates IOP increase after ocular massage.

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Forty subjects (76%) demonstrated IOP drop >1 mmHg (mean±SD=3.73±1.53 mmHg; maximum reduction: 7 mmHg). Clinically, digital ocular compression through the eyelids for several minutes may be enough to reduce the IOP. The central corneal thickness was not measured here, but using IOPcc could reduce the influence of CCT.2 We confirmed that ocular massage is effective in reducing IOP. Its influence on corneal biomechanics is relatively small. We do not know if subjects with high IOP will have a similar IOP change. Nevertheless, IOP reduction is independent of the initial IOP. The duration of IOP reduction requires further analysis.