Surgical outcomes of intermittent exotropia according to exotropia type based on distance/near differences.

We compare the surgical outcomes of intermittent exotropia of the basic, pseudo-divergence excess (pseudo-DE) and true divergence excess (true DE) types. A study was performed with 342 patients who had undergone surgery for intermittent exotropia of the basic, pseudo-DE or true DE type with a postoperative follow-up period of 6 months or more. The main outcome measures were postoperative angles of deviation at distance and near, and surgical success rates. Surgical success was defined as alignment between exodeviation of 10 PD and esodeviation of 5 PD at distance and near. Additionally, survival curves of recurrence were analyzed by the Kaplan-Meier method. The postoperative angles of deviation at both distance and near in pseudo-DE type were significantly smaller than those in basic type at the final examination (p = 0.003, <0.001). The final surgical success rate in pseudo-DE (70.2%) was better than in basic (46.3%) or true DE (28.6%) (p = 0.003, 0.01). Reoperation for recurrent exotropia was performed in 27% of the basic, 17% of the pseudo-DE, and 35.7% of the true DE cases. According to a survival analysis for recurrence, patients with pseudo-DE showed lower incidence of recurrence than did patients with basic and true DE (p = 0.003, 0.02). In conclusion, the patients with intermittent exotropia of the pseudo-DE type showed better surgical outcomes than those with the basic or true DE type. Pseudo-DE also showed a lower recurrence rate than did the other 2 groups.

The Heritability of Corneal and Ocular Higher-Order Aberrations in Koreans: The Healthy Twin Study.

PURPOSE: To estimate the genetic influences on corneal and ocular higher-order aberrations (HoAs) in the Korean population. METHODS: This was a prospective, family-based twin cohort study. A total of 1272 adult twins and their family members, who were part of the Korean Healthy Twin Study from 2007-2011, were included. Corneal and ocular HoAs were measured. The genetic influences on HoAs were investigated by using variance-component methods after adjusting for age and sex. Narrow-sense heritability was calculated. Intraclass correlation coefficients (ICCs) were used to calculate degrees of resemblance among different types of family relationships. RESULTS: A total of 269 monozygotic (MZ) twin pairs (including 176 MZ twin pairs and 93 orphan twins), 50 dizygotic (DZ) twin pairs (including 38 DZ twin pairs and 12 orphan twins), and 739 adult first-degree relatives of twins in 358 families were included. For more than half of corneal HoAs, the narrow-sense heritability estimates were not significant. Horizontal coma was highly heritable among corneal HoAs. The ICCs of horizontal coma from MZ twin pairs, pooled first-degree pairs, and spouse pairs were 0.41, 0.05, and 0.00, respectively. Among ocular HoAs, the estimated narrow-sense heritability of SA was 0.71 with the highest estimates. The ICCs of spherical aberration (SA) from MZ twins, pooled first-degree pairs, and spouse pairs were 0.76, 0.25, and 0.06, respectively. CONCLUSIONS: Both corneal and ocular HoAs demonstrated smaller heritability. Corneal HoAs showed low heritability, suggesting individual environmental factors explain most of the variance of these HoAs in the Korean population. Ocular HoAs were moderately heritable.

Corneal topographic and tomographic analysis of fellow eyes in unilateral keratoconus patients using Pentacam.

PURPOSE: To evaluate topographic and tomographic changes in fellow eyes in unilateral keratoconus (KCN) patients by comparing them with normal eyes. DESIGN: Retrospective comparative case series. METHODS: Fourteen eyes of 14 patients with unilateral KCN and 34 eyes of 34 refractive surgery candidates were divided into 3 diagnostic groups using a Pentacam rotating Scheimpflug camera: advanced KCN eyes of unilateral KCN (KCN group, 14 eyes), normal fellow eyes of unilateral KCN (fellow eye group, 14 eyes), and refractive surgery candidates (normal group, 34 eyes). Topographic and tomographic parameters, which were obtained from Pentacam using sagittal curvature, elevation, and corneal thickness maps, were compared among the 3 groups. Receiver operating characteristic (ROC) curves were used to identify cutoff points in discriminating between fellow and normal eyes. RESULTS: Keratometric asymmetry, topometric indices, and elevation differences (maximum - minimum) on both the anterior and posterior surfaces were statistically different (P < .05). On ROC curve analysis, keratometric asymmetry and topometric index were best at discriminating fellow eyes from normal, followed by elevation differences (maximum - minimum) on the posterior and anterior cornea surface. CONCLUSIONS: Fellow eyes in unilateral KCN showed differences in several parameters that were not detectable with the Pentacam detection program, when compared with normal. However, each single parameter alone is not sufficient to detect early changes; thus, elevation indices as well as indices of anterior curvature should be considered together.