Study of biometric parameters in family members of primary angle closure glaucoma patients

Abstract

Objectives To measure ocular biometric parameters in all possible untreated family members of index primary angle closure glaucoma (PACG) patients and to correlate these values among affected, unaffected, and suspected family members. Methods Anterior chamber depth (ACD), axial length (AL), lens thickness (LT), relative lens position, and central corneal thickness (CCT) were measured in first-and seconddegree relatives of index patients. These biometric parameters were compared among the relatives and index patients as well as among affected, unaffected, and suspected family members. Results Of the 108 family members included in the study, 34 (31.6%) were affected with primary angle closure, 19 (17.6%) were suspect, and 55 (50.7%) were unaffected family members. In comparison to index cases, ACD was 14.56% more in affected, 21.7% more in primary angle closure suspects and 34.92% more in unaffected family members. LT was 10.73, 11.1, 16% less and AL was 0.11, 3.53 and 5.37% more in affected, suspected, and unaffected family members, respectively. Lens position and CCT were not statistically different in the various subgroups. Conclusions ACD is narrowest, lens thickest, and AL shortest in family members affected with PACG compared to suspected and unaffected members. Although LT and ACD could change with advancing age, AL appears to be a marker to identify members at risk of angle closure glaucoma.

Prevalence of Angle Closure in Siblings of Patients With Primary Angle-closure Glaucoma

“…20,21 More recent studies have demonstrated that narrow angles are more likely to occur in women. 10,11 CCT was compared among the study groups and although CCT was lower in the PACG subgroup, none of the comparisons revealed a significant difference; these results are similar to those described by Lowe. 12 CCT has been established as a significant risk factor for open-angle glaucoma; whether this biometric parameter may also serve as an important risk factor for angle-closure glaucoma requires longitudinal studies on large cohorts of subjects with milder forms of the condition.…”

“…Our findings are remarkably similar to the 58.8% rate of "heritability" found in firstdegree relatives, including siblings, children, parents, and even spouses, of Singaporean subjects of diverse ethnic background 11 and very close to a 50% rate of angle-closure abnormalities in a study from India. 10 Other studies on the familial or genetic aspects of PACG date back to the 1960s and 1970s. [12][13][14][15] This series is the first from the Middle East to address the prevalence of angle closure in close relatives of subjects with PACG.…”

“…PACG has been more extensively studied in East Asians, Indians, Chinese, and recently in Singaporeans, demonstrating a positive family history in these geographical regions. [5][6][7][8][9][10][11] Heritability rates of 20% and 60% have been reported in siblings of PACG patients of white descent, and in residents of Singapore, including subjects of Chinese, Malay, and Indian origin. 9,11 Overall, it is believed that firstdegree relatives of subjects with PACG are at 3 to 6 times higher risk of the condition than the general population.…”

Anterior segment optical coherence tomography of acute primary angle closure

“…Angle between the peripheral posterior iris surface and the central posterior iris surface Iris root curvature distance: (IRCD) (mm) Distance between the peripheral end of the posterior iris and the angle point of the iris root curvature (see above) results of studies using ultrasound biomicroscopy and biometry for the quantitative assessment of anterior chamber structures [16][17][18][19][20][21]. In all of these studies, a shallow anterior chamber, a thick lens, a relatively short axial length, and a hyperopic refractive error were the factors associated most with APAC.…”

Lens parameters as predictors of intraocular pressure changes after phacoemulsification

“…15 However, there have been conflicting reports on the importance of LP and RLP, possibly because LT and ACD, which are the two constituents of these parameters, are interdependent and could compensate for each other. [16][17][18] With the advent of AS-OCT, additional parameters related to LP have been assessed. Lens vault (LV) is a novel parameter introduced by Nongpuir et al, 19 defined as the perpendicular distance between the line joining the two scleral spurs and the anterior pole of the lens.…”