Intravitreal injection (IVI) is a procedure in which medication is administered directly into the vitreous cavity. Since the introduction of anti-vascular endothelial growth factor (anti-VEGF) therapy two decades ago, the number of IVIs performed has increased substantially. These injections are now routinely conducted as outpatient procedures for the treatment of various retinal disorders such as diabetic macular edema (DME), age-related macular degeneration (AMD), retinal vein occlusion (RVO), polypoidal choroidal vasculopathy(PCV), and pseudophakic cystoid macular oedema.
Eligible participants were identified among patients scheduled for intravitreal injections (IVI) at the day-care surgery unit of the University of Malaya Medical Centre. Written informed consent was obtained after participants were provided with the participant information sheet and screened based on the study's inclusion and exclusion criteria. A simple random sampling method was used. After consent, each participant was randomly assigned a number using the Random Number Generator from the website https://www.calculatorsoup.com
, which generates numbers without repeats. Odd numbers were allocated to the music intervention group, and even numbers to the control group.
Data collection followed the Data Collection Proforma. Demographic information included age, gender, ethnicity, marital status, comorbid conditions, occupation, and education level. Before entering the operating room (OR), participants' baseline blood pressure (BP₀) and heart rate (HR₀) were recorded.
In this study, a standardised, copyright- and royalty-free piano composition-Andromeda (Piano Solo) by Gabriele Tosi, available for free on YouTube.com-was used. The piece was selected for its consistent tempo of 55-60 beats per minute (BPM) and stable average sound level of 60 decibels (dB). Music was played in the waiting room using a JBL Go3 speaker, with audio transmitted wirelessly via Bluetooth from a Huawei Nova 5T smartphone (Huawei, China). To maintain consistency, the speaker volume was calibrated each morning using the Sound Meter application (Google Play Store), ensuring the sound level remained at approximately 60 dB-comparable to normal conversational volume. Inside the OR, music was played directly from a computer with an attached speaker, and the same calibration method was applied. This volume level was chosen to avoid disrupting the surgeon's focus while allowing clear verbal communication between operating theatre staff and the participant. After listening to music for at least 15 minutes, participants were called into the OR according to their sequence. The same music continued to play in the OR for the music group until the end of the procedure.
Upon entering the OR, baseline samples of salivary alpha-amylase (sAA\_before), BP (BP₁), and HR (HR₁) were measured. Salivary alpha-amylase (sAA) was assessed using the Cocoro Meter (Nipro Inc., Japan). Participants in the control group underwent the same procedure without background music.
All participants, regardless of group allocation, received standard IVI in accordance with clinical practice. The injections were performed under topical anaesthesia using five drops of proparacaine hydrochloride 0.5%, administered at least five minutes before the procedure. The periocular skin was cleaned with 10% povidone-iodine, while the conjunctiva and fornices were irrigated with 5% povidone-iodine and left for three minutes. The eye was then draped, and an eyelid speculum was applied. IVIs were performed under sterile conditions using a 30-gauge needle inserted 3.5-4.0 millimetres from the limbus.
During IVI, additional measurements of BP (BP₂) and HR (HR₂) were taken at the third minute. A second sAA measurement (sAA\_after) was also obtained. Participants' pain levels were assessed using the Visual Analogue Scale for Pain (VAS-P).
Since approximately 30 patients were scheduled for IVI on any given day, their sequence of IVI was categorised for statistical analysis as early (8:00-10:00 a.m.), middle (10:00 a.m.-12:00 p.m.), and late (12:00-2:00 p.m.).
The duration of the procedure, type of anti-vascular endothelial growth factor (anti-VEGF) used, participant sequence, ocular diagnosis, number of prior IVIs, and history of ocular surgery were all documented. Each participant was recruited only once for the study, and no follow-up was required.
