Background: Anterior megalophthalmos is a rare congenital disease which mainly features enlargement of the anterior segment. Cataract surgeries in anterior megalophthalmos can be challenging due to the anatomical anomalies while the studies upon the surgical design have been less integrated. Case presentation: A 37-year-old woman presented with progressively blurred vision in the right eye after a transient fever 10months ago. Her ocular history included hypermetropia with a spherical equivalent of +4.00 OU. The review of systems showed bilateral varus deformity of distal interphalangeal joints on the little fingers. The patient denied family history of hereditary ocular diseases and her sister was born with uterus didelphys. On initial examinations, the corrected distance visual acuity was hand motion OD and 20/33 OS. Her intraocular pressure was 15 mmHg OD and 16 mmHg OS. Horizontal corneal diameter was 14 mm OD and 13.88 mm OS and axial length was 24.87 mm OD and 25 mm OS. Anterior segment photography showed bilateral iridal atrophy with deficiency in pupillary dilation and white cortically mature cataract in the right eye. Inspection by anterior segment optical coherence tomography indicated bilateral augmented anterior chambers with backward iridal concave on horizontal orientation. Ultrasound biomicroscopy showed partially peripheral anterior synechiae and pectinate ligaments at chamber angle in both eyes and opacified lens with the apparently elongated suspensory ligaments in the right eye. A deliberately selected 1-piece foldable intraocular lens (IOL) with frame haptics was implanted after phacoemulsification for good IOL stability. During the follow-up, the visual rehabilitation appeared relatively good and a lower degree of IOL dislocation comparing with existing reports was verified by OPD-Scan III aberrometry. Conclusions: We presented the challenges and the original findings from a case of congenital anterior megalophthalmos with white cataract who underwent phacoemulsification and IOL implantation. This is the first report describing the comparison of the different IOL power calculation formulas in anterior megalophthalmos. Compared to the SRK/T and the Holladay II formulas, the Haigis formula could be a more accurate choice for the IOL calculation in anterior megalophthalmos according to our case. Moreover, the deliberate selection of IOLs is essential for IOL stability in these patients.