Anterior chamber depth - a predictor of refractive outcomes after age-related cataract surgery

Abstract

Background: Anterior chamber depth (ACD) is becoming a hot topic and plays an important role in correcting the refractive errors (REs) after cataract surgery. The aim of this study was to assess the ACD changes and their relationship with the REs after phacoemulsification and intraocular lens (IOL) implantation in patients with age-related cataracts.

Methods: One hundred forty-five eyes of 125 age-related cataract patients from the Department of Ophthalmology, Tangdu Hospital, China, were recruited. IOL Master was used for axial length (AL) and the IOL power calculation measurements, and the Pentacam HR device was used for the ACD and lens thickness (LT) measurements. Every patient underwent uncomplicated phacoemulsification by a single surgeon using a single technique. Postoperative refraction results were obtained at 1 month. The appropriate formula used for the IOL power calculation was chosen depending on the AL, specifically the Hoffer Q (AL < 22.0 mm), SRK/T (22.0 mm ≤ AL ≤ 30.0 mm), and Haigis (AL > 30.0 mm) formulas.

Results: The postoperative ACD was deepened and tended to stabilize gradually after 2 weeks. A concurrent hyperopic shift (0.57 ± 0.47 D) was observed when the change in the ACD was less than 1.65 mm, whereas a myopic shift (- 0.18 ± 0.62 D) occurred contrarily, and the difference between the two groups was statistically significant (P < 0.0001). The change in ACD was significantly larger in the shallow anterior chamber (1.92 ± 0.40 mm) than in the deep chamber (1.33 ± 0.42 mm) (P < 0.0001). Similarly, the change in ACD was larger in the short AL (2.12 ± 0.37 mm) than in the long AL (1.32 ± 0.49 mm). The postoperative ACD and refractive changes were correlated with the preoperative ACD and AL (P < 0.0001), respectively. Two regression formulas were proposed: postoperative ACD = 3.524 + 0.294 × preoperative ACD and postoperative ACD = 3.361 + 0.228× (preoperative ACD + 1/2 LT).

Conclusions: The results of this study showed that the ACD deepened and was associated with a concurrent RE after cataract surgery. Postoperative changes in the ACD were related to the preoperative ACD and AL, which determined the refraction status and visual quality. The regression formula of the postoperative ACD could provide a theoretical basis for predicting refractive errors in the clinic.

Keywords: Anterior chamber depth; Axial length; Cataract; Pentacam HR; Refractive errors.

Fig. 1

Comparison of the postoperative ACD from different visits. ACD: anterior chamber depth. (*P = 0.016, n = 145)

Fig. 2

Correlation analysis of the postoperative refractive errors. a The scatter plot of the relationship between the postoperative change in ACD and the postoperative RE. b The scatter plot of the relationship between AL and postoperative RE. (n = 123, P < 0.001). ACD: anterior chamber depth; AL: axial length; D: dioptre; RE: refractive errors

Fig. 3

Correlation analysis of the postoperative changes in ACD. a The scatter plot of the relationship between the preoperative ACD and the postoperative change in ACD. b The scatter plot of the relationship between the AL and the postoperative change in ACD. (n = 123, P < 0.001). ACD: anterior chamber depth; AL: axial length

Fig. 4

Correlation analysis of the postoperative ACD. a The scatter plot of the postoperative ACD and the preoperative ACD. (n = 123, P < 0.001); b The scatter plot of the postoperative ACD and LT. (n = 55, P > 0.05); c The scatter plot of the postoperative ACD and preoperative ACD +1/2 LT. (n = 55, P < 0.01). ACD: anterior chamber depth; LT: lens thickness