Standardizing the Yamane flanged intrascleral haptic fixation: A framework for efficacy, complication mitigation, and reproducible training

Table 1 Clinical indications for the Yamane scleral-fixated intraocular lens technique

Category	Clinical indication	Surgical context	Typical etiology
Aphakia	Aphakia after complicated cataract surgery	Insufficient capsular support prevents standard in-the-bag implantation; Yamane fixation allows stable posterior chamber IOL placement without sutures	Posterior capsule rupture, zonular dialysis
IOL-capsular bag complex instability	Late dislocation of in-the-bag IOL-capsular bag complex	Progressive zonular weakness leads to displacement of the entire complex; fixation independent of residual capsule is required	Pseudoexfoliation syndrome, zonulopathy, high myopia, aging
Trauma	Traumatic lens loss or unstable capsular remnants	Loss of crystalline lens or unstable capsule makes conventional fixation unreliable; Yamane technique permits controlled posterior chamber positioning	Ocular trauma
Secondary aphakia	Aphakia after IOL explantation	Removal of opacified or malpositioned IOL may leave insufficient capsular support; Yamane fixation enables secure secondary implantation	IOL opacification, malposition, prior surgical complications
Post surgical	Vitreoretinal surgery/PPV complications	Capsular instability after pars plana vitrectomy	Compromised capsular integrity

IOL: Intraocular lens; PPV: Pars plana vitrectomy.

Table 2 Summary of key studies informing the methodological recommendations

Ref.	Study design	n	Key outcomes/findings	Notable limitations/risk of bias	Role in this review
Yamane et al[1], 2014	Prospective case series	14 eyes	Original description of flanged ISHF; demonstrated secure scleral fixation without sutures	Very small sample; single surgeon; no comparative control group; short follow-up	Foundational technique description
Yamane et al[2], 2017	Prospective case series	100 eyes	Flanged modification introduced; strong centration results; low dislocation rate	Single center; single surgeon; no randomization; retrospective outcome assessment	Primary clinical validation
Stem et al[9], 2019	Retrospective case series	55 eyes	Learning curve analysis; improved outcomes with increasing surgical experience	Retrospective; small sample; variable follow-up; potential selection bias	Learning curve and training
Rocke et al[4], 2020	Retrospective case series	112 eyes	Tunnel geometry analysis; IOL stability data; CT Lucia PVDF haptic outcomes	Retrospective; heterogeneous surgical technique across cases; variable follow-up	Tunnel geometry & IOL stability
Schranz et al[11], 2023	Comparative retrospective study	78 eyes	AR40e vs CT Lucia outcomes; haptic behavior and flange formation comparison	Retrospective; limited long-term follow-up; single center; small groups	IOL model comparison
Zhang et al[5], 2024	Systematic review & meta-analysis	1847 eyes (pooled)	Pooled CME rate approximately 13%-14%; favorable visual outcomes; shorter OR time vs sutured fixation	High heterogeneity across included studies; retrospective designs dominate; variable definitions of complications	Broadest comparative evidence
LoBue et al[17], 2024	Bench/cadaveric experimental study	Ex vivo (4 IOL models)	Haptic tensile strength: CT Lucia 153 N > MA60AC 1.00 N > AR40e 087 N > LAL 0.83 N	Non-clinical; ex vivo findings may not fully predict in vivo behavior; limited generalizability	Haptic material & tensile strength

Studies are listed chronologically. CME: Cystoid macular edema; IOL: Intraocular lens; ISHF: Intrascleral haptic fixation; PVDF: Polyvinylidene fluoride; PMMA: Polymethylmethacrylate; LAL: Light-adjustable lens; OR: Operating room.

Table 3 The Yamane technique: Advantages, limitations, and key technical challenges of the Yamane scleral-fixated intraocular lens technique

Category	Details
Advantages	Sutureless - eliminates suture degradation, erosion, and late dislocation
	Minimal conjunctival manipulation preserves tissue
	Shorter operative time vs sutured fixation
	Small incision (30-gauge needles), self-sealing sclerotomies
	Good IOL centration and axial stability
	Posterior chamber positioning maintains normal anatomy
	Comparable or superior outcomes vs sutured fixation
	Cost-effective (no sutures, fewer reoperations)
	Mechanical stability via intrascleral friction + flanges
	Reproducible with standardized steps
Limitations	Significant learning curve requiring precise coordination
	Refractive predictability less precise than in-the-bag IOL
	Requires specific three-piece IOLs with appropriate haptic material (e.g., PMMA or PVDF)
	Limited options for premium IOLs
	Risk of tilt/decentration with asymmetric placement
	Haptic deformation risk during externalization
	Not ideal for very thin sclera (high myopia, Marfan)
	Higher CME rates than sutured techniques
	Potential late haptic exposure if inadequately buried
	Limited long-term data beyond 5 years
	Often benefits from a complete vitrectomy
Key technical challenges	Symmetric and precise scleral tunnel creation
	Controlled haptic capture within the needle lumen
	Symmetric beveled entry to prevent lens tilt
	Uniform flange and haptic formation to promote lens centration
	Adequate burial of flanged ends to prevent erosion or migration
	Assessment of lens centration intraoperatively with irregular pupils

IOL: Intraocular lens; PMMA: Polymethyl methacrylate; PVDF: Polyvinylidene fluoride; CME: Cystoid macular edema.

Table 4 Stepwise procedural checklist for the Yamane flanged intrascleral haptic fixation technique

Step	Stage	Action
1	IOL selection	Confirm three-piece IOL with PMMA haptics compatible with 30-gauge needle lumen
2	Scleral marking	Mark symmetric scleral entry points 180° apart, 2.0-2.5 mm posterior to the limbus
3	Needle insertion	Insert 30-gauge needles with bevel orientation optimized for haptic capture (bevel-up preferred); maintain entry angle of 20° relative to the limbus and 5° relative to the iris surface
4	Tunnel adequacy	Confirm intrascleral tunnel length ≥ 2.0 mm to ensure adequate haptic retention
5	Haptic externalization	Externalize haptics through needle lumen with controlled, minimal force to avoid deformation
6	Flange formation	Form flanges using low-temperature cautery; target flange diameter 0.3-0.5 mm; avoid excess heat to prevent haptic brittleness
7	Haptic retraction	Retract flanges into scleral tunnels and confirm fully seated position
8	IOL verification	Verify IOL centration and tilt under the operating microscope before wound closure

PMMA: Polymethylmethacrylate; IOL: Intraocular lens.

Table 5 Standardized surgical parameters for the Yamane flanged intrascleral haptic fixation technique

Surgical parameter	Recommended value/range	Rationale
Needle gauge	30-gauge	Matches standard haptic diameter; minimizes scleral trauma
Scleral entry distance from limbus	2.0-2.5 mm	Avoids ciliary body; ensures adequate fixation depth
Entry angle	Approximately 20° to limbus/approximately 5° to iris plane	Achieves tunnel length ≥ 2.0 mm for stable haptic retention
Intrascleral tunnel length	≥ 2.0 mm	Reduces risk of haptic slippage and IOL dislocation
Needle separation (symmetry)	180° apart	Ensures IOL centration and minimizes postoperative tilt
Bevel orientation	Bevel-up (preferred); surgeon-dependent	Facilitates haptic capture and reduces deformation risk
Flange diameter	0.3-0.5 mm	Prevents haptic slippage without excessive thermal damage
Cautery application	Low-temperature, brief contact	Avoids haptic brittleness or fracture from excessive heat

IOL: Intraocular lens.