The Barrett Universal II, Haigis, Hoffer Q, Holladay 2, RBF method and SRK/T formulas were equally accurate in predicting the IOL power in eyes shorter than 22.0 mm.

PurposeThis study aimed to evaluate whether different anterior chamber depth (ACD) affects the predictive accuracy of intraocular lens formulas in eyes with axial length (AL) less than 22 mm.MethodsEighty-five eyes of 85 patients with AL less than 22 mm were included in this retrospective study, which were divided into three groups: Group 1, ACD less than 2.4 mm; Group 2, ACD between 2.4 and 2.9 mm; and Group 3, ACD greater than 2.9 mm. Optical biometry with partial coherence interferometry was performed in all cases. The median absolute error (MedAE) was compared by Friedman’s test, using the optimized lens constant, among seven formulas (Barrett Universal II, Haigis, Hill-RBF, Hoffer Q, Holladay 1, Holladay 2, and SRK/T) in each group.ResultsFriedman’s test showed no significant difference in MedAE among all formulas in Groups 1 and 3. However, as the Haigis formula had the highest MedAE and lowest percentage of eyes within ±0.25 Diopter, it is least preferred in Group 1. On the contrary, in Group 3 it fared the best, having the least MedAE and highest percentage of eyes within ±0.25 Diopter. In Group 2, Friedman’s test gave significant difference, and post-hoc analysis showed statistical superiority of Haigis over the Holladay 1 (p=0.02), Holladay 2 (p=0.01), Hill-RBF (p=0.04), and SRK/T (p=0.02) formulas. However, there was no statistical difference between the Barrett Universal II, Haigis, and Hoffer Q formulas.ConclusionConsidering the ACD in eyes with AL less than 22 mm, Haigis is the preferred formula while SRK/T proved to be the worst formula in Groups 2 and 3.

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BACKGROUND Ultrasound biomicroscopy (UBM) is a non-invasive procedure to visualise the structures of the anterior segment using high frequency ultrasound. Any abnormalities in the structures like the iris, ciliary body and zonules can be easily detected. In case of corneal oedema, the Descemet's membrane can be detected with UBM than the slit-lamp biomicroscopy. It plays a useful diagnostic tool in glaucoma. It differentiates between open and closed angle closure. It also helps in the diagnosis of plateau iris configuration and malignant glaucoma. Bleb status and tenon's cyst can be visualized by the UBM. It plays a major role to rule out angle recession or cyclodialysis cleft in cases of trauma. Zonular dialysis and iridodialysis as well as the integrity of the posterior capsule can be assessed with UBM. It is the only modality which can easily diagnose pars plannits or cyclitic membranes noninvasively. In cases of unexplained hypotony, it helps to diagnose ciliary body atrophy or traction on the ciliary body. This article is a short overview describing the indications and uses of anterior segment pathologies.