Factors affecting patients' pain intensity during in office intravitreal injection procedure

PURPOSE: To determine factors associated with patients' comfort during routine in-office intravitreal injection. METHODS: Sixty patients receiving intravitreal injections over 15 months for macular edema because of diabetes, age-related macular degeneration, or retinal vein occlusion who were randomized into 3 groups to receive 1 of 3 commonly used forms of anesthesia-TetraVisc, proparacaine HCl, or tetracaine HCl-before receiving intravitreal injection were studied. Fifteen minutes after injection, patients were asked to rate their pain from 0 (no pain/no distress) to 10 (agonizing pain/unbearable distress) using a Visual Analog Pain score survey. Self-reported pain scores were stratified by age, gender, diagnosis, injection number, substance injected, needle gauge, and visual acuity improvement. RESULTS: Intravitreal injection was associated with low pain scores. Patients receiving tetracaine reported a statistically significant lower pain score (3.05 ± 2.01) than patients receiving proparacaine (3.17 ± 2.18) or TetraVisc (3.3 9± 2.26; P < 0.01). Other important factors influencing pain score significantly (P < 0.01) included improved vision from previous injection, female sex, and age >65 years. Pain scores decreased with each consecutive injection. CONCLUSION: Pain associated with intravitreal injection is generally mild, and may be associated with epidemiologic and environmental factors.