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

Official title

Speculum-Free Intravitreal Injection Using Cotton-Tipped Applicator Retraction: A Randomized Controlled Trial Comparing Pain Perception, Procedure Duration, Patient Satisfaction, and Safety Between Eyelid Speculum and Cotton-Tipped Applicator Retraction Techniques

Overview

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.

Detailed description

Background:

Intravitreal injection is one of the most frequently performed ophthalmic procedures worldwide. Eyelid specula are standard for keeping the eye open during injection but may cause discomfort, corneal exposure, and patient anxiety. Cotton-tipped applicator retraction is an alternative technique that may reduce pain and improve patient experience, but comparative randomized data on procedure time, satisfaction, and safety are lacking.

Study Design:

Single-center, prospective, parallel-group randomized controlled trial. Patients are randomly assigned 1:1 to speculum (Group A) or cotton-tipped applicator retraction (Group B). Stratified permuted block randomization is performed using Study Randomizer software with six strata: diagnosis (nAMD / DME / RVO) × prior injection history (injection-naïve / previously injected).

Interventions:

All patients receive standard preparation: topical tetracaine 0.5% (two instillations), 5% povidone-iodine ophthalmic drops (≥5 min contact), and 10% povidone-iodine periocular skin preparation. Anti-VEGF agents used are bevacizumab, aflibercept, or faricimab (per clinical indication), injected via Terumo 31G insulin syringe at the superotemporal quadrant. Post-injection levofloxacin 0.5% drops are instilled immediately after needle withdrawal.

Outcome Measures:

Primary: Pain VAS (0-10 cm) immediately post-procedure; procedure duration (seconds) from retraction device placement to removal. Secondary: Patient satisfaction (5-item Likert scale, total 5-25); safety outcomes (subconjunctival hemorrhage, corneal abrasion, endophthalmitis, IOP elevation) at Day 0, Day 1 (telephone), and Week 4.

Blinding:

Patients cannot be blinded to retraction method. Pain VAS is assessed by an independent assessor blinded to group assignment. Procedure timing is recorded by a circulating nurse blinded to the randomization list.

Sample Size:

Based on Chen et al. (2025), assuming pooled SD of 1.71 for pain VAS (Cohen's d = 0.57), with Bonferroni correction (α = 0.025, power 80%), 52 patients per group are required for pain and 46 for procedure duration. With 15% dropout allowance, the final target is 60 patients per group (120 total).

Interventions

• Procedure Eyelid Speculum Retraction
  A wire eyelid speculum is inserted to retract the eyelids prior to intravitreal anti-VEGF injection (bevacizumab, aflibercept, or faricimab) using a Terumo 31G insulin syringe at the superotemporal quadrant. The speculum is removed immediately after needle withdrawal.
• Procedure Cotton-Tipped Applicator Retraction
  Two sterile cotton-tipped applicators are used to retract the eyelids (speculum-free) prior to intravitreal anti-VEGF injection (bevacizumab, aflibercept, or faricimab) using a Terumo 31G insulin syringe at the superotemporal quadrant. Applicators are removed immediately after needle withdrawal.

Primary outcome measures

• Pain Perception [Time frame: Immediately after intravitreal injection (Day 0)]
• Procedure Duration [Time frame: During intravitreal injection procedure (Day 0)]
• Patient Satisfaction [Time frame: 15-30 minutes after intravitreal injection (Day 0)]
• Procedure-Related Complications [Time frame: Day 0, Day 1, and Week 4 post-injection]

Eligibility criteria

Inclusion criteria

• Age 18 years or older
• Diagnosed with neovascular age-related macular degeneration (nAMD), diabetic macular edema (DME), or retinal vein occlusion (RVO)
• Scheduled for intravitreal anti-VEGF injection (bevacizumab, aflibercept, or faricimab)
• Able to provide written informed consent

Exclusion criteria

• Active ocular infection or inflammation
• Known allergy to povidone-iodine, tetracaine, or levofloxacin
• Inability to cooperate with the injection procedure
• Concurrent participation in another interventional clinical trial
• Anatomical eyelid abnormality precluding use of either retraction technique

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Supportive care

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Chen HRQ, de Andrade GC, Arimori LK, Lerner FK. Comparison of intravitreal injection techniques with and without a speculum using eyelid retraction with a cotton-tipped applicator. Int J Retina Vitreous. 2025 Oct 29;11(1):119. doi: 10.1186/s40942-025-00739-5. PMID 41163036

Identifiers

NCT: NCT07481500 · WURCT5954

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗