Contrary to the
prior hypothesis that statin antioxidant effects may slow the natural aging process of the lens, researchers utilizing a military health-care system database for a cohort analysis have concluded that the risk of cataract is increased among statin users compared to non-statin users. The risk-benefit ratio of statin use, specifically for primary prevention, should be carefully weighed with this knowledge.
In order to compare the risks of development of cataracts between statin users and nonusers, researchers created a propensity score-matched cohort using 46,249 patients, 44 variables and retrospective data from October 1, 2003 to March 1, 2010. Primary analysis examined the risk of cataract in the cohort. Secondary analysis examined the risk of cataract in patients with no comorbidities according to the Charlson Comorbidity Index. A sensitivity analysis was conducted to repeat the secondary analysis in patients taking statins for two, four and six years.
Based on medication fills during fiscal year 2005, patients were divided into two groups: Group 1 (n=13,626), statin users who received at least a 90-day supply of statins; and Group 2 (n=32,623), nonusers who never received a statin throughout the study. For the primary analysis, 6,972 pairs of statin users and nonusers were matched. The risk of cataract was higher among statin users in comparison with nonusers in the matched cohort (odds ratio: 1.09; 95 percent CI, 1.02-1.17). In secondary analysis, after adjusting for identified confounders, the incidence of cataract was higher in statin users than nonusers (odds ratio: 1.27; 95 percent CI, 1.15-1.40). Sensitivity analysis confirmed this relationship.
JAMA Ophthalmol 2013;131:1427-1434.
Leuschen J, Mortensen E, Frei C, Mansi E, et al.
CXL for Progressive Keratoconus: Two-year Outcomes
A progressive case series of 42 eyes from 32 patients with progressive keratoconus treated with corneal cross-linking shows that CXL is effective in improving uncorrected distance visual acuity, corrected distance visual acuity, topographic measures and most corneal higher-order aberrations. A significant reduction was observed in apical keratometry; this reduction directly correlated with an improvement in visual acuity.
Main outcomes (UDVA; CDVA; refractive changes; topographic data; corneal aberrations) were measured at baseline, six, 12 and 24 months after treatment. Two years after CXL treatment, the UDVA (p<0.001), CDVA (p<0.001) and spherical equivalent (p=0.048) improved significantly. The corneal topographic data revealed significant decreases in apical keratometry (p<0.001), differential keratometry (p=0.031) and central keratometry (p=0.003) compared with baseline measurements. Aberration analyses revealed a significant reduction in coma (p=0.016), trefoil (p=0.018), secondary astigmatism (p<0.001), quatrefoil (p=0.031), secondary coma (p<0.001) and secondary trefoil (p=0.001). Corneal HOA (except quatrefoil) demonstrated a significant correlation with postoperative CDVA; the highest correlations were for coma (rho=0.701, p<0.001), secondary astigmatism (rho=0.519, p=0.001) and total HOA (rho=0.487, p=0.001). However, the corneal HOA changes were not statistically associated with improved visual acuity. After treatment, the reduction in apical keratometry was the only variable that correlated with the improvement in CDVA (rho=0.319, p=0.042).
Ghanem R, Santhiago M, Berti T, Netto M, et al.
IOP After Phaco in Medically Controlled OAG Patients
University of Washington researchers found a small average decrease in IOP in patients with open-angle glaucoma after phacoemulsification; however, a sizeable proportion of medically controlled glaucoma patients experienced an increase in IOP or required more aggressive treatment to control IOP postoperatively.
In this retrospective case series, a total of 157 eyes of 157 open-angle glaucoma patients without prior incisional glaucoma surgery undergoing phacoemulsification by a single surgeon between January 1997 and October 2011 were evaluated. Patient charts were reviewed to obtain demographic information; preoperative glaucoma medications; severity and treatments measures; and preoperative and postoperative IOP.
The average preoperative IOP of 16.3 ±3.6 mmHg decreased to 14.5 ±3.3 mmHg at one year (p<0.001). Sixty eyes (38 percent) required additional medications or laser for IOP control within the first year postoperatively, or had a higher IOP at postoperative year one without medication change. Among eyes without postoperative medication changes (n=102), higher preoperative IOP (p<0.001), older age (p=0.006) and deeper anterior chamber depth (p=0.015) were associated with lower postoperative IOP.
Am J Ophthalmol 2014;157:26-31.
Slabaugh M, Bojikian K, Moore D, Chen P.
Risk Calculation Variability in Ocular Hypertensive Subjects
Researchers investigating the longitudinal variability of glaucoma risk calculation in ocular hypertensive subjects have shown that the estimated five-year risk of conversion to primary open-angle glaucoma among untreated OHT patients varies significantly, with a trend towards increasing over time. Within the same individual, the estimated risk can vary almost tenfold based on the variability of IOP, central corneal thickness, vertical cup-to-disc ratio (VCDR) and visual field pattern standard deviation (VFPSD). Therefore, a single risk calculation measurement may not be sufficient for accurate risk assessment, informed decision-making by patients and physician treatment recommendations.
Clinical variables collected at baseline and during follow-up include age, CCT, IOP, VCDR and VFPSD. These variables were used to calculate the five-year risk of conversion to POAG at each follow-up visit using the Ocular Hypertension Treatment Study and European Glaucoma Prevention Study calculator (found at ohts.wustl.edu/risk/calculator.html). The researchers also calculated the risk of POAG conversion based on the fluctuation of measured variables over time, assuming the worst-case scenarios (final age; highest pattern standard deviation; lowest CCT; highest IOP; highest VCDR) for each patient. Risk probabilities were plotted against follow-up time to generate slopes of risk change over time.
The charts of 27 untreated OHT patients (54 eyes) followed for a mean of 98.3 ±18.5 months were reviewed. Seven individuals (25.9 percent) converted to POAG during follow-up. The mean five-year risk of conversion for all patients in the study group ranged from 2.9 percent to 52.3 percent during follow-up. The mean slope of risk change over time was 0.37 ±0.81 percent increase per year. The mean slope for patients who reached a POAG endpoint was significantly greater than for those who did not (1.3 ±0.79 vs. 0.042 ±0.52 percent per year, p<0.01). In each patient, the mean risk of POAG conversion increased almost tenfold when comparing the best-case scenario with the worst-case scenario (5 percent vs. 45.7 percent, p<0.01).
J Glaucoma 2014;23:1-4.
Song C, de Moraes C, Forchheimer I, Prata T, et al.
Continuous Monitoring of IOP Using a Contact Lens Sensor
French researchers evaluating a new contact lens sensor (CLS) proposed to continuously monitor intraocular pressure over 24 hours found that while the CLS is an accurate and reproducible method to characterize nyctohemeral IOP rhythm in healthy participants, it does not allow for estimating IOP value in millimeters of mercury corresponding to the relative variation of the electrical signal measured.
Twelve healthy young volunteers were housed in a sleep laboratory and underwent four 24-hour sessions of IOP measurements over six months. After initial randomized attribution, the IOP of the first eye was continuously monitored using a CLS and the IOP of the fellow eye was measured hourly using noncontact tonometry. Two sessions with NCT measurements in one eye and CLS measurements in the fellow eye, one session with CLS measurements in only one eye and one session with NCT measurements in both eyes were performed.
A nonlinear least squares, dual-harmonic regression analysis was used to model the 24-hour IOP rhythm. Comparison of acrophase, bathyphase, amplitude, midline estimating statistic of rhythm, IOP values, IOP changes and agreement were evaluated in the three tonometry methods. A significant nyctohemeral IOP rhythm was found in 31 of 36 sessions (86 percent) using NCT and in all sessions using CLS. Hourly awakening during NCT measurements did not significantly change the mean phases of the 24-hour IOP pattern evaluated using CLS in the contralateral eye. Throughout the sessions, intraclass correlation of coefficients of the CLS acrophase (0.6, p=0.01; 95 percent CI, 0.1-0.9); CLS bathyphase (0.7, p=0.01; 95 percent CI; 0.1-0.9); NCT amplitude (0.7, p=0.01; 95 percent CI, 0.1-0.9); and NCT midline estimating statistic of rhythm (0.9, p<0.01; 95 percent CI, 0.9-1) were significant. When performing NCT measurements in one eye and CLS measurements in the contralateral eye, the IOP change at each point, normalized from the first measurement (9 a.m.), was not symmetric individually or within the population.
JAMA Ophthalmol 2013;131:1507-1216.
Mottet B, Aptel F, Romanet JP, Hubanova R, et al.