Prevalence of Orbscan II corneal abnormalities in relatives of patients with keratoconus

Abstract

Keratoconus traits are common in relatives of patients with keratoconus. There prevalence may have been previously underestimated by using placido image-based topography alone where corneal pachymetry and posterior elevation are not assessed. This study suggests an autosomal dominant pattern of inheritance with variable expressivity in some families.

Videokeratoscopic indices in relation to epidemiological exposure to keratoconus

“…The distribution of the ISD parameter of our control group is similar to the median value of approximately 0 D reported by Rabinowitz et al [17] and Bühren et al [22] but slightly lower than other studies on subjects with no epidemiological exposure to keratoconus, which range between mean values of 0.23 D (Rabinowitz et al [23]), 0.41 D (Wang et al [24]), or 0.42 (Li et al [15]) to 0.58 D (Li et al [3]). The two latter studies also highlighted a trend among unaffected relatives of keratoconus subjects towards greater inferior-superior (IS) dioptric values than normal controls, which was not apparent in our study.…”

Changes in Corneal Biomechanics in Patients With Keratoconus After Penetrating Keratoplasty

“…1 Both autosomal dominant and autosomal recessive inheritance patterns have been identified in pedigree analyses, familial aggregation analyses, and segregation analyses of patients with keratoconus. 2,3 Eyes with keratoconus are known to have different corneal biomechanics compared to normal eyes such as more elasticity and less rigidity. 4 The ocular response analyzer (ORA; Reichert, Inc, Depew, NY) is a recently introduced device that measures the biomechanical properties of the cornea in vivo.…”

Evaluation of early corneal topographic changes in children with Down syndrome

“…Steepness in the lower half of the cornea and values higher than 1.2 have been reported in favor of keratoconus (13,14). In these series, the differences between average I-S values of DS patients and controls did not reach statistical significance.…”

“…Average keratometry of ≥47.2, I-S ≥1.2, thinnest pachymetry ≤463 µm, and keratoconus indices derived from the Pentacam device were used as parameters and thresholds for abnormality (13,14).…”