PURPOSE

To evaluate changes in the anterior segment of myopic eyes and assess anterior biometry as a function of axial length (AL).

DESIGN

Retrospective investigational study.

PARTICIPANTS

Patients evaluated for phakic intraocular lens surgery at a tertiary eye care centre.

METHODS

Patients with corrected visual acuity > 20/40 and AL > 24.5 mm were included in the study. Posterior staphyloma and maculopathy were ruled out in all the patients, and 176 eyes were included for analysis. AL was measured with partial coherence interferometry, while keratometry, central corneal thickness (CCT), anterior chamber depth (ACD), and horizontal white to white (WTW) were measured with slit-scanning topography. Group 1 included 55 eyes with AL < 26.5 mm, group 2 had 57 eyes with AL between 26.5 and 28.5 mm while group 3 had 64 eyes with AL > 28.5 mm.

MAIN OUTCOME MEASURE

Correlation of AL with anterior biometry.

RESULTS

The mean AL of the study eyes was 27.88 + 2.14 mm. The mean values of ACD (2.99 mm), CCT (0.52 mm), WTW (11.68 mm), and keratometry (43.62 D) were within the normal range. Overall, very weak correlations could be established between AL and CCT (R = 0.17, p = 0.02), AL and keratometry (R = - 0.28, p < 0.001), and AL and WTW (R = 0.22, p = 0.002), while ACD did not relate to AL significantly. The ACD and CCT did not relate significantly to AL in any of the three groups. Keratometry had a weak negative relation with AL in groups 1 and 2, while WTW had a weakly positive relation with AL in group 2 only. No variable had any significant relation with AL in group 3.

CONCLUSION

There is disproportionate elongation of the eyeball in myopic patients with very weak or no correlation between anterior biometry and AL. This discord is more in longer eyes. Such a scenario can be challenging to a refractive surgeon treating highly myopic eyes and needs further evaluation.