Blepharoptosis After Repeated Intravitreal Anti-VEGF Injections: A Prospective Study

Design: prospective, single-center, longitudinal, non-interventional observational study conducted in the Department of Ophthalmology, University of Health Sciences, Fatih Sultan Mehmet Training and Research Hospital, Istanbul, Turkey.

No study-driven intervention is performed. The decision to treat, the anti-VEGF agent (ranibizumab, aflibercept or bevacizumab), the injection interval and the total number of injections are determined solely by the treating retina specialist on clinical grounds. Injections are given under routine sterile conditions, topical anesthesia and with an eyelid speculum, as in standard practice; the study therefore evaluates the combined exposure of injection plus speculum use and cannot isolate the speculum-specific mechanical effect.

The injected eye is the study eye and the non-injected fellow eye is the control eye; each participant serves as their own control. All participants are assessed at baseline and at months 1, 3, 6 and 12. At every visit, for both eyes, MRD-1, MRD-2 and levator function are measured by the same examiner where possible using a standard technique. MRD-1 is the distance in millimetres between the corneal light reflex and the upper eyelid margin in primary gaze; MRD-2 is the distance between the corneal light reflex and the lower eyelid margin; levator function is the upper eyelid excursion from downgaze to upgaze with frontalis action neutralised. The cumulative number of intravitreal injections, the agent used and the number of eyelid speculum uses are recorded at each visit. Clinically significant blepharoptosis is defined as an MRD-1 of 2 mm or less and/or a decrease of 2 mm or more from baseline, evaluated separately for each eye at every visit.

Sample size: based on a paired comparison of the change in MRD-1. Using the 0.60 mm (SD 0.61) MRD-1 reduction at 12 months reported by Bermudez-Castellanos et al., and assuming a conservatively clinically meaningful difference of 0.50 mm with a standard deviation of paired differences of 1.00 mm (dz = 0.50), a two-sided alpha of 0.05 and 90% power require a minimum of 44 evaluable participants; allowing for approximately 25% attrition over 12 months, the target enrollment is 60.

Statistical analysis: normality by the Shapiro-Wilk test; between-eye change compared by paired t-test or Wilcoxon signed-rank test; repeated measures across the five timepoints by repeated-measures ANOVA or the Friedman test; frequency of clinically significant blepharoptosis compared between eyes by the McNemar test; associations between the number of injections or speculum uses and the change in eyelid measurements by Pearson or Spearman correlation; a sensitivity analysis compares eyelid measurement change among anti-VEGF agents. Two-sided p < 0.05 is considered significant. Analyses are performed in SPSS.

Inclusion criteria

• Age 18 years or older
• Planned initiation of intravitreal anti-VEGF injection in one eye only for a retinal disease
• No prior intravitreal injection in either eye
• Able to attend the scheduled follow-up visits and to cooperate for the duration of the study
• Reliable MRD-1, MRD-2 and levator function measurement possible in both eyes (clear corneal light reflex, clearly visible eyelid margin, able to maintain primary gaze)
• Signed informed consent

Exclusion criteria

• Pre-existing blepharoptosis or significant eyelid malposition at the baseline examination
• Previous ptosis surgery, blepharoplasty or other eyelid surgery that may affect upper eyelid anatomy
• History of myasthenia gravis, oculomotor nerve palsy, Horner syndrome, facial nerve palsy or a similar neurologic or neuromuscular disorder
• History of orbital trauma, orbital surgery or orbital disease
• Advanced dermatochalasis, eyelid retraction, entropion, ectropion or marked facial asymmetry precluding reliable eyelid measurement
• Need for intravitreal injection in both eyes during the study period
• Ocular or periocular surgery during follow-up that may affect upper eyelid position
• Inability to comply with follow-up visits or incomplete measurements
• Withdrawal of consent
• Inability to obtain reliable eyelid measurements due to severe blepharospasm, advanced corneal opacity, marked eyelid edema, or inability to maintain head or neck position or to cooperate