Correlation between the dysfunctional lens index and subjective grading for different types of cataracts

To determine whether the dysfunctional lens index scale (DLI) measured by iTrace is a valuable and objective measurement for evaluating the severity of cataract.

Single-centre, retrospective, noninterventional observational study.

Participants seen at the Eye Physicians and Surgeons' clinic from January 2023 to January 2024 were included.

All patients underwent a comprehensive ophthalmologic examination by a single surgeon. This included DLI measurement via the ray-tracing aberrometry system (iTrace Visual Function Analyzer by Tracey Technologies) and an eye examination after pupil dilation and classification of the type of cataracts on the basis of the Lens Opacification Classification System II (LOCS II). Inclusion criteria included a clinical diagnosis of any cataract type, age ≥18 years, and healthy eyes with only cataracts. Participants were excluded if they had a previous history of ocular trauma, ocular surgery, including laser refractive treatment, irregular corneal astigmatism, corneal opacity, scarring, or dystrophies, ocular diseases other than age-related cataract, and pupil diameters of <4.0 mm in the dark.

We included 165 eyes from 99 patients comprising of 69 females and 30 males with a mean age of 68.72 years ± 8.82 (range 39-89 years). The DLI was significantly correlated with the severity of nuclear cataract (P = 0.0002) and severity of posterior subcapsular cataract (P = 0.0129). When the DLI increased, the severity of nuclear cataract and posterior subcapsular cataract decreased. There was no statistically significant difference between the mean DLI and the severity of anterior cortical cataract (P = 0.7119). There was a significant correlation (-0.5149) between DLI and best-corrected visual acuity (P = 2.368^e-12); when DLI increased, best-corrected visual acuity decreased. The optimal DLI cut-off for predicting cataract surgery was 8.01, yielding a sensitivity of 0.83, specificity of 0.81, and an area under the curve of 0.82. Values below this threshold were associated with a greater likelihood of requiring surgery.

The DLI can be a valuable objective measurement for the severity of nuclear and posterior subcapsular cataracts but not for anterior cortical cataract. A DLI threshold of 8.01 demonstrated moderate discriminative ability for surgical status in this cohort; however, given the retrospective design, DLI should be considered an adjunctive or confirmatory measure rather than an independent criterion for cataract surgery. This study highlights the transformative potential of objective metrics like the DLI, offering significant advancements in identifying visually significant cataracts and their management.