Abstract
Purpose :
Variation in body stature (height) is shown to be directly proportional to variation observed in ocular biometry, for example, axial length (AL) and anterior chamber depth (ACD). Short AL and a shallow ACD have also been shown to associate with individuals with occludable angles (primary angle closure suspect, PACS). Therefore, the objective of this study is to assess the relationship between height and ocular biometry, and height and PACS in a population from Nepal.
Methods :
This ongoing family-based study involves recruitment of members of the Jirel population, a small endogamous ethnic group from the Jiri region of Nepal. Participants undergo a comprehensive eye examination that includes measurements of AL, ACD and lens thickness (LT) by A-scan ultrasound biometry, and measurements of corneal curvature radii (CCR) and angle of the anterior segment (AAS) by optical coherence tomography. Additionally, a 4-mirror gonioscope is used to grade the iridocorneal angle using the Shaffer system and slit lamp biomicroscopy is used to grade the peripheral ACD using the van Herick system. PACS is defined in accordance with ISGEO criteria. In SOLAR, bivariate quantitative modeling was used to assess the phenotypic (ρp) and genetic (ρg) relationships between height and ocular biometry (phakic eyes only), and a variance components method was used to assess height as a significant PACS covariate.
Results :
All 1,234 study participants (57.8% female) examined in this study belong to a single extended pedigree. The mean (SD) age at exam is 41.0 (16.0) years, the mean (SD) height is 1.544 (0.083) meters and the prevalence of PACS is 4.5%. We observe a significant positive correlation between height and several ocular dimensions; AL (ρp=0.252, p=3.34×10-15), ACD (A-scan biometry: ρp=0.073, p=0.0188; the van Herick system: ρp=0.124, p=2.15×10-5), horizontal CCR (ρp=0.104, p=0.0011), and AAS (the Shaffer system: ρp=0.117, p=6.63×10-5). Variation in height and AL in the Jirel population are influenced by a common set of genetic loci (ρg=0.397, p=3.55×10-8). Height is also a significant predictor for PACS susceptibility (p=0.0175).
Conclusions :
Our data support the relationship that shorter stature is positively correlated with dimensions of the eye that are associated with risk of PACS. This may be a contributing factor for the high prevalence of PACS in the Jirel population of Nepal.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.