Alleviating Panretinal Photocoagulation Associated Ocular Pain With Vibratory Stimulation

Background:

Panretinal photocoagulation (PRP) is a widely used laser treatment for proliferative diabetic retinopathy (PDR). However, the associated ocular pain can make the procedure uncomfortable, leading to increased treatment visits or missed appointments. This pain is multifactorial and can be exacerbated by factors such as anxiety and hypervigilance. Traditional pain management techniques, such as regional anesthesia, are effective but invasive and carry potential complications. Oral medications have largely proven ineffective in alleviating PRP-related pain.

The Gate-Control Theory of pain posits that non-noxious stimuli can inhibit pain signals by activating A-β fibers, effectively "closing the gate" to pain transmission through A-δ and C fibers. The most relatable example is the mother rubbing a child's knee after an impact injury in the affected region. Transcutaneous electrical nerve stimulation (TENS) which utilizes the Gate-Control Theory of pain, has been shown to reduce ocular pain during PRP. However, its use raises practical concerns, including the need to carefully adjust pulse width, intensity, and frequency for effective pain relief. Additionally, some patients may find the muscular contractions or paresthesia uncomfortable. TENS is also contraindicated in individuals who are pregnant, have epilepsy, or have pacemakers. Vibratory stimulation activates cutaneous mechanoreceptors to reduce pain during intramuscular and subcutaneous injections. This technique is safer and less invasive than TENS and is therefore an ideal candidate for evaluating its effect in pain reduction during PRP. This study has the potential for an innovative concept by utilizing a vibratory device integrated within the PRP machine headrest.

Hypothesis:

Vibratory stimulation is expected to reduce ocular pain during PRP by activating cutaneous mechanoreceptors and inhibiting pain transmission, as suggested by the Gate-Control Theory. Its non-invasive nature makes it a practical alternative to traditional pain management methods, potentially enhancing patient comfort during the procedure.