Miri 4-points marker: a low-cost marking device for flanged intrascleral intraocular lens fixation with modified Yamane technique

BACKGROUND: Yamane's flanged intrascleral intraocular lens (IOL) fixation is widely used in eyes without capsular support, but limitations in conventional conjunctival marking may affect surgical precision and consistency. This study compared the clinical outcomes of modified Yamane scleral-fixated IOL implantation using the Miri 4-Points Marker versus Castroviejo calipers, assessing visual outcomes and complications between these two approaches. METHODS: This retrospective cohort study at a single hospital of Malaysia included 44 eyes operated on between 2024 and 2025. Conjunctival markings were made using either the Miri 4-Points Marker or Castroviejo calipers. Two 30-gauge thin-walled needles created right-angled sclerotomies 2 mm posterior to the limbus. IOL haptics were externalized through the needles, cauterized to form a flange, and inserted into scleral tunnels. Descriptive statistics and binary logistic regression were used to assess factors associated with postoperative visual outcomes. RESULTS: Among 44 patients (mean age 64.4 ± 9.7 years, 77.3% male) who underwent intrascleral IOL fixation, the Miri 4-Points Marker was used in 72.7% of cases. Clinical outcomes with the Miri 4-Points Marker were comparable to Castroviejo calipers. Mean postoperative uncorrected visual acuity (UCVA) and corrected distant visual acuity (CDVA) were 0.7 (± 0.4) and 0.4 (± 0.3) logMAR, respectively. At one month postoperatively, 17.2% achieved good UCVA, increasing to 30.8% after excluding ocular comorbidities; 41.4% achieved good CDVA, rising to 46.2% without ocular comorbidities. On univariable analysis, high corneal astigmatism (> 2.5 D) was associated with poorer UCVA across all patients, regardless of Miri 4-Points Marker use (OR = 0.07, 95% CI: 0.01, 0.78, p = 0.03). Multivariable analysis did not identify any independent predictors. CONCLUSIONS: The Miri 4-Points Marker is a feasible and safe adjunct for conjunctival marking in Yamane intrascleral IOL fixation. Observed short-term outcomes were similar to caliper-based marking, although this study's chronological design precludes any conclusion of equivalence.