Arcus senilis and mortality in a population with diabetes

An Evaluation of the Arcus Corneae For Age Estimation

Although the arcus corneae (AC) has long been used as an age indicator for forensic purposes, its diagnostic value has not been evaluated. To evaluate the AC as a predictor of chronological age, the author has studied the correlation of AC with respect to age of the deceased. A cross-sectional study was conducted of 342 Thai corpses at the Maharat Nakhon Ratchasima Hospital, Thailand. AC was graded into three levels: no AC, incomplete ring, and complete ring. One-way analysis of variance, chi-square test, binomial logistic regression, sensitivity, specificity, predictive values, and likelihood ratios were used for analysis. The Cohen's kappa was used to determine the intraobserver and interobserver reliability. The prevalence of AC and the probability of complete AC were significant higher in corpses aged 60 years and above than in those under 60 years. Consequently, this study confirmed that the prevalence of AC was significantly correlated with the age of Thai individuals. If the complete AC is used as an indicator of age of 60 years and above, complete AC has high sensitivity (92.56%) but low specificity (72.85%), low positive predictive value (65.12%), but high negative predictive value (94.71%). For diagnostic value, the presence of AC can be used for age screening but not for absolute confirmation. The absence of AC indicates young age, incomplete AC indicates middle age, and complete AC indicates old age. The high intraobserver and interobserver reliability provides assurance of the value of AC as a means to estimate personal age.

Intra-session repeatability of iridocorneal angle measurements provided by a Scheimpflug photography-based system in healthy eyes

PURPOSE

The purpose of this study was to evaluate intra-session repeatability of measurements of the iridocorneal angle at different meridians in the nasal and temporal areas in healthy eyes using the Sirius Scheimpflug photography-based system in glaucoma analysis mode.

METHODS

A total of 43 eyes of 43 patients ranging in age from 36 to 79 years were enrolled in the study. All eyes received a comprehensive ophthalmologic examination including a complete anterior segment analysis with the Costruzione Strumenti Oftalmici [CSO] Sirius system. Three consecutive measurements of nasal and temporal angles at 0°, ±10°, ±20°, and ±30° meridians were obtained in order to assess the intra-session repeatability of iridocorneal angle measurements provided by the device using the glaucoma analysis mode. Within-subject standard deviation (Sw), coefficient of variation (CV), and intraclass correlation coefficient (ICC) values were calculated.

RESULTS

The mean Sw was 1.07 ± 1.09°, 1.22 ± 1.53°, 0.66 ± 0.51°, 0.86 ± 0.57°, 0.68 ± 0.65°, 0.84 ± 0.68°, and 0.91 ± 0.70° at the temporal 30°, 20°, 10°, 0°, -10°, -20°, and -30° positions, respectively. Mean Sw was 3.13 ± 3.15°, 3.43 ± 3.63°, 2.75 ± 2.29°, 2.19 ± 1.55°, 1.90 ± 1.49°, 2.14 ± 1.74°, and 2.24 ± 2.06° at the temporal -30°, -20°, -10°, 0°, 10°, 20°, and 30° positions, respectively. Mean CV ranged from 1.36 ± 1.05 % (nasal 0° position) to 10.92 ± 13.95 % (nasal -20° position). ICC values ranged from 0.778 to 0.972.

CONCLUSIONS

The glaucoma analysis mode of the Sirius system provides consistent measurements of the iridocorneal angle at different meridians in healthy eyes, with slightly less consistency for nasal measurements. It may be considered a clinically useful non-invasive technique for the detection of potentially occludable angles.

A population-based study of corneal arcus and its risk factors in Iran

PURPOSE

To determine the prevalence of corneal arcus, its risk factors, and its relationship to ocular and visual indices.

METHODS

In this cross-sectional study, 300 clusters were randomly selected from Shahroud in the north of Iran, using multistage sampling. A total of 20 people were invited to participate from each cluster. After enrollment, all optometric, biometric and ophthalmic exams were conducted on site.

RESULTS

Of 6311 people invited, 5190 (82.2%) participated in the study. The prevalence of corneal arcus was 23.3% (95% confidence interval, CI, 22.1-24.6), and 98.4% were bilateral cases. The prevalence of corneal arcus was higher in men (odds ratio, OR, 2.02, 95% CI 1.8-2.3, p < 0.001) and increased with age (OR 1.1/year, p < 0.001). In a multivariable-adjusted regression model, age (OR 1.1/year, p = 0.006), male sex (OR 1.30, p = 0.001), diabetes (OR 0.7, p < 0.001), smoking (OR 1.5, p = 0.003), outdoor activity (OR 1.4, p = 0.006), systolic blood pressure (OR 1.01, p = 0.012), and diastolic blood pressure (OR 0.99, p = 0.016) were significantly correlated with corneal arcus. Including biometric components in another model, corneal thickness (OR 0.99, p < 0.001), anterior chamber depth (OR 0.68, p < 0.001) and corneal radius of curvature (OR 1.59, p < 0.001) were significantly correlated with corneal arcus.

CONCLUSION

This study adds valuable information to the epidemiology of corneal arcus in Iran and the Middle East. In people aged over 60 years, nearly 50% of the study population had corneal arcus. Older age, male sex, smoking, and systolic hypertension were risk factors for corneal arcus. Corneal arcus was also associated with thin and flat corneas and shallow anterior chamber depth.

Use of Scheimpflug corneal anterior-posterior imaging in ray-tracing intraocular lens power calculation

PURPOSE

To examine improvement with the use of Scheimpflug imaging of the anterior and posterior corneal surfaces in the accuracy of ray-tracing intraocular lens (IOL) power calculation for normal cataractous eyes.

METHODS

Prospective case series comprised 136 eyes of 136 consecutive patients who had undergone cataract surgeries. Scheimpflug imaging of the cornea was included with routine preoperative examinations. Postoperative refractions were predicted using three methodologies; ray-tracing calculation using Scheimpflug imaging and Placido topography, ray-tracing calculations using Placido topography, and the SRK/T formula using autokeratometry. Prediction errors from the manifest refraction at 1 month postoperatively were compared between the methods. Influence of the posterior corneal curvature was also evaluated.

RESULTS

Mean prediction errors were 0.008, -0.103 and -0.042 D, respectively without significant difference between the three methods (p = 0.23). The prediction errors were significantly correlated with the posterior corneal curvature when the Scheimpflug imaging was not used (p < 0.03).

CONCLUSION

Use of Scheimpflug imaging in ray-tracing IOL power calculation was as accurate as the other calculations in normal cases, showing no bias in the posterior corneal curvature, as is the case with the other calculations.

Corneal topography parameters after superior clear corneal incision cataract surgery in arcus lipoides

PURPOSE

To compare changes in corneal topographic parameters after cataract surgery in eyes with different severities of arcus lipoides.

METHODS

Fourty eyes of 40 patients (23 women, 17 men, age 71.3+/-20.4 years, range 40 to 89 years) were studied prospectively in a consecutive, non-interventional, comparative series of cases. Eyes were classed in three groups (0 to 2) according to the assessed grade of arcus lipoides (none, <180 degrees, >180 degrees). Corneal topography (Tomey TMS-2) was performed preoperatively and at 1 and 10 days and 1 and 3 months following cataract surgery (superior 4.0 mm clear corneal incision, no suture). Keratometric astigmatism (Dcyl), surface regularity index (SRI), surface asymmetry index (SAI), and potential visual acuity (PVA) were evaluated for the different groups and time-points, using the Kruskal-Wallis, Wilcoxon, and Mann-Whitney statistical tests.

RESULTS

No significant preoperative difference was found in mean Dcyl, SRI, or PVA; preoperative SAI was lower in Group 1. Postoperatively Dcyl was increased at day 1 in Groups 1 and 2, and remained higher in Group 2 until month 1. At month 3 significant differences among Groups 0, 1, and 2 disappeared.

CONCLUSIONS

The 4.0 mm superior clear corneal incision is a safe method for cataract surgery in the presence of arcus lipoides. This procedure induces greater corneal astigmatism, surface irregularity, and lower PVA in the early postoperative period in cases with arcus lipoides than in normal corneas. Concerning final results, wound healing was not affected by greater severity of arcus lipoides, although stabilization of the corneal surface tended to be slower.

Corneal arcus and hyperlipidemia: findings from an older population

PURPOSE

To quantify the association between arcus and hyperlipidemia in an older population.

DESIGN

Cross-sectional population-based study.

METHODS

Arcus and serum lipids were measured in the Blue Mountains Eye Study (n = 3,654, aged >49 years). Arcus was graded as absent, partial (<180 degrees) or circumferential (> or =180 degrees). Associations between arcus and hyperlipidemia were assessed using logistic regression, adjusting for age and vascular risk factors.

RESULTS

Arcus was strongly associated with age (P <.0001). After age adjustment, arcus was associated with male sex (P <.01) and diabetes (P <.02) but not with hypertension or smoking. Corneal arcus was significantly associated with progressively higher levels of total cholesterol over 5 mmol/l. Adjusted odds increased from 1.6 for cholesterol 6.0 to 6.9 mmol/l to 4.6 for cholesterol >8.0 mmol/l, and was 1.9 for high triglyceride >3.0 mmol/l.

CONCLUSION

This population-based finding confirms that corneal arcus was associated with hypercholesterolemia and hypertriglyceridemia in older persons.