LAUSR

Dear Editor Normative data is data that characterizes what is usual in a defined population at a specific point or period and can be of enormous importance to physicians in all spheres of medical sciences. Such data seek to describe rather than explain phenomena. There is a paucity of normative data related to ocular parameters originating from different regions of India. In any case, most of the studies describing normative data that are available in the literature are either in the Caucasian population[1‐4] or describe exclusively either anterior segment[5] or posterior segment findings.[6‐8] Yet others have reported biometry in conditions such as cataract[9] and keratoconus[10] within the remit of their study design, comparing one or several parameters in diseased conditions. We collected decade‐wise normative data prospectively from 156 eyes of healthy subjects of South‐Indian origin between the age group of 10–60 years, encompassing both anterior and posterior segments, using the latest available technology. The central corneal thickness (CCT) and anterior and posterior corneal curvatures (ACC and PCC) were measured using WaveLight Oculyzer II (Alcon, Tx, USA), axial length (AL). Lens thickness (LT) and anterior chamber depth (ACD) were measured using Lenstar LS 900 (Haag Streit, Bern, Switzerland), and the retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and peripapillary and subfoveal choroidal thickness (CT) were measured using swept‐source OCT (SS‐OCT) by using Triton Dri OCT Plus (Topcon Inc, NJ, USA). The mean ACC and PCC were 7.66 ± 0.26 mm and 6.37 ± 0.27 mm, respectively. CCT, ACD, LT, and AL were 536.05 ± 29.95 μm, 3.37 ± 0.38 mm, 3.81 ± 0.38 mm, and 23.16 ± 0.90 mm, respectively. LT correlated positively with age (P < 0.001); ACD and AL correlated negatively with age (P < 0.001 and 0.05, respectively) [Fig. 1‐top and center]. We obtained an annual increase in LT by 0.023 mm and ACD decreased by 0.014 mm. An age‐related increase in LT further shallows the AC, which decreases with age. Recognizing a shallow AC is important as such individuals are not only at risk of developing angle‐closure glaucoma but may also present challenges during cataract surgery,[11-13] particularly in pseudoexfoliation eyes.[11]