Shallow Anterior Chamber Linked to Higher Hyperopic Shift After Cataract Surgery: Study
China: A shallow anterior chamber depth (ACD) may significantly influence visual outcomes after cataract surgery, increasing the likelihood of postoperative hyperopic shift even in patients with otherwise normal eye length, a new study has found.
Published in the Journal of Ophthalmology, the research led by Dongyan Xu from the Jinan No.2 People’s Hospital evaluated how preoperative ACD affects refractive error following phacoemulsification and intraocular lens (IOL) implantation in patients with age-related cataract. The study also compared the predictive accuracy of several modern IOL calculation formulas.
This prospective study (June 2023–December 2024) grouped patients by anterior chamber depth into shallow (ACD <2.5 mm) and normal (2.5–3.5 mm). Preoperative biometrics were measured using the IOLMaster 700, with IOL power mainly calculated via the Barrett Universal II formula. Refractive outcomes were evaluated at 1 and 3 months postoperatively, and the performance of four IOL formulas—Barrett Universal II, Kane, EVO 2.0, and Hill-RBF 3.0—was compared.
A total of 103 patients were analyzed, with 57 in the shallow ACD group and 46 in the normal group.
The study led to the following findings:
- A significant difference in refractive outcomes was observed between the two groups, with patients having shallow anterior chamber depth showing a markedly greater hyperopic shift than
- those with normal ACD.
- The hyperopic shift in shallow ACD cases was linked to a more pronounced postoperative deepening of the anterior chamber.
- The magnitude of hyperopic shift was inversely related to preoperative ACD, meaning shallower chambers before surgery were associated with greater refractive error.
- The hyperopic shift was also directly correlated with the extent of postoperative ACD change, indicating that greater deepening after surgery increased the likelihood of refractive inaccuracy.
- All intraocular lens calculation formulas demonstrated a tendency toward hyperopic outcomes in eyes with shallow ACD.
- Among the formulas, the Barrett Universal II showed the highest predictive accuracy, with the lowest mean absolute error and the highest proportion of eyes achieving outcomes within ±0.50 diopters.
- In patients with normal anterior chamber depth, all four formulas performed comparably well without significant differences in accuracy.
The researchers highlighted anterior chamber depth and lens thickness as key independent predictors of postoperative refractive outcomes, with shallow ACD and thicker lenses increasing the risk of unexpected hyperopia.
However, the study had limitations, including a small sample size, use of a single intraocular lens type, and possible variability in refractive measurements, warranting further large-scale research.
Overall, the findings stress the need for thorough preoperative evaluation. In eyes with shallow ACD, using more accurate formulas like Barrett Universal II and slightly adjusting IOL power may help optimize visual outcomes and minimize refractive errors.
Reference:
Xu, D., Liu, S., Zhang, H., Dang, H., Tang, W., & Wang, J. (2025). Effect of Shallow Anterior Chamber on Postoperative Refractive Status in Patients of Age-Related Cataract. Journal of Ophthalmology, 2026(1), 3854811. https://doi.org/10.1155/joph/3854811
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