Cataract surgery predictions: The rarer the eye characteristics, the greater the differences between formulas

【Financial News, Jeju Province = Reporter Jeong Yong-bok】 The more a patient’s eye structure before cataract surgery deviates from the typical pattern, the greater the differences in predictions made by intraocular lens calculation formulas, a study found.
According to Jeju National University Hospital on the 9th, a research team comprising Professor Jeong Jin-ho of the Department of Ophthalmology and resident physician Sa U-jin received the Best Poster Award in the cataract and refractive surgery category at the 136th Korean Ophthalmological Society Conference and the 6th Asia-Pacific Ophthalmic New Technology Society Conference, held at the Grand Walkerhill in Seoul from October 30 to November 1.
The study was titled “Association Between the Rarity of Age-Adjusted Multivariate Ocular Biometry and Prediction Discrepancies Among Intraocular Lens Power Calculation Formulas.” Resident physician Sa U-jin was the first author, and Professor Jeong Jin-ho was the corresponding author.
According to the study abstract released by the Korean Ophthalmological Society, the team analyzed biometric data from 8,164 eyes belonging to 4,498 people at a single medical institution. After adjusting for age several measurements—including axial length, corneal curvature, anterior chamber depth and lens thickness—the researchers assessed how far each eye’s structural characteristics deviated from the typical pattern.
Cataract surgery is a treatment in which a clouded lens is removed and an artificial lens is implanted. Before surgery, the eye’s structure is measured to determine the appropriate power of the intraocular lens, but the predicted postoperative refractive value may differ depending on the calculation formula, even for the same patient.

The study found that the median difference between the highest and lowest predicted refractive values produced by the calculation formulas was 0.84 diopters for typical eyes. It increased to 1.04 diopters for relatively rare eye types and 1.31 diopters for very rare types. A diopter is a unit used to express the refractive state of the eye or the power of a lens.
The researchers also confirmed a statistical association in which differences between formulas’ predictions increased as eye structures became rarer. The team said the association remained even after accounting for extreme measurements of axial length and corneal curvature.
However, differences between formulas’ predictions should be distinguished from actual surgical outcomes. The team separately analyzed 85 eyes from 80 people for which postoperative refraction test results could be compared with the formulas’ predictions. The finding that actual refractive errors were greater in very rare eye types was not statistically significant.
The study suggests that its findings may help determine before surgery whether it would be useful to consider several calculation formulas for patients with atypical eye structures. It did not demonstrate that doing so improves actual surgical accuracy, and the research team said further validation using data from other medical institutions and additional patients is needed.


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