Managing Cataract In Extreme Nanophthalmos: Surgical And Refractive Challenges

Accurate IOL power calculation in eyes with extremely short axial length remains a major challenge. Predictive accuracy of modern biometric formulas decreases significantly in eyes with AL <20 mm, particularly in ultra-short eyes (<16 mm), where minor errors in effective lens position can lead to large postoperative refractive deviations. This report presents cataract surgery in a 39-year-old patient with extremely axial hyperopia, highlighting the persistent unpredictability of refractive outcomes despite modern formulas and sequential second-eye adjustment.

Private ophthalmology clinic performing a high volume of phacoemulsification surgeries.

A 39-year-old male with progressive bilateral visual decline due to cataract presented with UDVA 0.09 and CDVA 0.2 in both eyes. Manifest refraction was +17.0 D OD and +17.5 D OS. Optical biometry revealed extremely short axial length (AL 15.99 mm OD, 15.93 mm OS), consistent with nanophthalmos. Multiple modern IOL formulas converged on +50.0 D.

Sequential phacoemulsification was performed. In OD, a +50.0 D custom posterior chamber IOL was implanted; due to the unusually large optic and overall diameter, corneal incision enlargement and 10-0 nylon suturing were required to maintain anterior chamber integrity. Postoperative autorefraction revealed +6.0 D residual hyperopia.

For OS, IOL power was increased to +55.0 D based on the first-eye outcome. Similar surgical modifications were applied. Postoperative autorefraction showed residual hyperopia of +1.75 D. No intraoperative complications occurred, including capsular rupture, zonular dialysis, or suprachoroidal events.

Surgical strategy prioritized anterior chamber stability with OVD-assisted maintenance and careful capsular bag preparation. Thorough OVD removal minimized postoperative IOP elevation. Despite formula-based power selection and second-eye adjustment, significant hyperopic surprise persisted, illustrating the inherent unpredictability of refractive outcomes in extreme short eyes.

Cataract surgery in extreme nanophthalmos (AL- 16 mm) can be performed safely, but postoperative refraction is often unpredictable. In our patient, multiple modern IOL formulas suggested similar lens powers, yet a significant hyperopic surprise occurred after implantation of a +50.0 D IOL, and residual hyperopia persisted even after increasing the fellow-eye IOL to +55.0 D. This case underscores the inherent limitation of IOL power prediction in very short eyes and highlights the importance of thorough preoperative counseling regarding possible residual refractive error and the need for postoperative optical correction.