Speculum-Free Intravitreal Injection Using Cotton-Tipped Applicator Retraction: A Randomized Trial of Pain, Procedure Time, Patient Satisfaction, and Safety

Plain-language summary

This randomized controlled trial compares two techniques for eyelid retraction during intravitreal injection (IVI) of anti-VEGF agents: the standard wire eyelid speculum (Group A) versus cotton-tipped applicator retraction (Group B) in patients with neovascular AMD, diabetic macular edema, or retinal vein occlusion. The study evaluates four outcomes: (1) patient pain perception measured by a 10-cm visual analogue scale immediately after injection; (2) procedure duration from retraction device placement to removal; (3) patient satisfaction assessed by a 5-item Likert scale; and (4) safety including rates of subconjunctival hemorrhage, corneal abrasion, endophthalmitis, and intraocular pressure elevation. A novel syringe cap technique using the Terumo 31G insulin syringe plastic cap as an injection-site marker (3.5 mm for pseudophakic eyes, 5.0 mm for phakic eyes from the limbus) is employed in both groups, replacing the traditional caliper. Randomization is stratified by diagnosis and prior injection history using permuted block randomization (block sizes 4 and 6). The target sample size is 120 patients (60 per group) at Walailak University Hospital, Nakhon Si Thammarat, Thailand.

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