While working with a large data set of Goldmann applanation tonometry (GAT) intraocular pressure (IOP) measurements for a separate investigation, we observed that the IOP distribution favored even-numbered values. Study of this phenomenon has been limited, and this larger data set enabled inquiry that showed new insight concerning the manner in which this bias may vary according to IOP level. This analysis of 69,537 right eyes measured via GAT demonstrated that even-number preference was essentially absent in the 21 to 24 mm Hg range, but then the bias gradually strengthened as it moved away from this range in a lower or higher IOP direction. These data suggest that there is an examiner proclivity to measure and/or record GAT readings as even-numbered values, but that this tendency varies depending on IOP level.

It is often assumed that genotoxic substances will be detected more easily by using in vitro rather than in vivo genotoxicity tests since higher concentrations, more cytotoxicity and static exposures can be achieved. However, there is a paucity of data demonstrating whether genotoxic substances are detected at lower concentrations in cell culture in vitro than can be reached in the blood of animals treated in vivo. To investigate this issue, we compared the lowest concentration required for induction of chromosomal damage in vitro (lowest observed effective concentration, or LOEC) with the concentration of the test substance in blood at the lowest dose required for biologically relevant induction of micronuclei in vivo (lowest observed effective dose, or LOED). In total, 83 substances were found for which the LOED could be identified or estimated, where concentrations in blood and micronucleus data were available via the same route of administration in the same species, and in vitro chromosomal damage data were available. 39.8 % of substances were positive in vivo at blood concentrations that were lower than the LOEC in vitro, 22.9 % were positive at similar concentrations, and 37.3 % of substances were positive in vivo at higher concentrations. Distribution analysis showed a very wide scatter of > 6 orders of magnitude across these 3 categories. When mode of action was evaluated, the distribution of clastogens and aneugens across the 3 categories was very similar. Thus, the ability to detect induction of micronuclei in bone marrow in vivo regardless of the mechanism for micronucleus induction, is clearly not solely determined by the concentration of test substance which induced chromosomal damage in vitro.

Précis: In this study conducted in Chicago, IL, intraocular pressure (IOP) level was found to have a subtle, but measurable, annual pattern. Reasonable evidence is presented for a time-of-year variation in IOP. Adequate numbers of subjects must be studied to detect this small variation. Purpose: The aim was to investigate the relationship between IOP and time of year. Methods: During a separate investigation, patients from 2011 to 2018 (dataset A, N=3041) in an urban, academic facility in Chicago, IL received an examination that included Goldmann applanation tonometry. Regression analyses assessed the relationship between time of year and IOP. Two additional datasets, 1 collected in a similar manner during 1999 and 2002 (dataset B, N=3261) and another consisting of all first visits during 2012 and 2017 (dataset C, N=69,858), were used to confirm and further investigate trends. Results: For dataset A, peak mean IOP occurred in December/January (15.7±3.7/15.7±3.8 mm Hg) and lowest in September (14.5±3.1 mm Hg). The analysis suggested conventional quarterly analysis (January to March, etc.) can conceal time-of-year relationships because of inadequate statistical power and timing of IOP variation. Multiple linear regression analysis, with a November-to-October reordering, detected an annual, downward IOP trend (P<0.0001). Analysis of dataset B confirmed this trend (P<0.001). Fourier analysis on datasets A and B combined supported a 12-month IOP cycle for right/left eyes (P=0.01/P=0.005) and dataset C provided stronger evidence for an annual periodicity (P<0.0001). Harmonics analysis of dataset C showed a repeating pattern where IOP trended downward around April, and then back upward around October. Conclusions: This analysis strongly supports a demonstrable annual, cyclical IOP pattern with a trough to peak variation of ≈1 mm Hg, which has a seasonal relationship.

Purpose: The purpose of this study was to further investigate factors associated with Krukenberg’s spindle (KS) presence in a primary eye care setting. Methods: As part of a larger investigation, several practitioners in an academic eye care facility in Chicago, IL, USA evaluated patients for the long anterior zonule (LAZ) trait during 2011 to 2018, and data were collected on ocular/systemic health, lifestyle, and demographic variables, including the presence of a KS. Multivariate regression was used to assess relationships to KS presence. Results: Analysis included 3501 subjects with mean age of 51 ± 15 years (18–98 years; 65% women; and 84% African American). Among the right eyes, 57 (1.6%) had a KS, with this group having a mean age of 62 ± 13 years (25–86 years; 75% women; and 82% African American). There were 120 subjects (3.4%) with right eye LAZ, with mean age of 64 ± 11 years (36–91 years; 77% women; and 92% African American). There were 19 of 57 (33.3%) KS eyes that also had LAZ. Controlling for other factors, variables with the strongest relationship to KS presence were the LAZ trait (odds ratio [OR] = 12.2, 95% confidence interval [CI] = 6.5 to 22.8, P < 0.0001) and advancing age (OR = 1.3 per decade, 95% CI = 1.3 to 1.9, P < 0.0001). Conclusions: In the population studied, KS presence had its strongest relationship to the LAZ trait and advancing age. The KS-LAZ relationship may not be well-known, but these data strongly suggest that pigment dispersion signs, such as a KS, should prompt the clinician to consider the LAZ trait as a potential etiology, especially because LAZ is associated with higher IOP and possibly glaucoma.

Purpose To investigate the relation between intraocular pressure (IOP) and the idiopathic long anterior zonule (LAZ) trait. Methods Patients presenting for primary eye care were examined for LAZ, identified as radially oriented zonular fibers with central extension >1.0 mm beyond the normal anterior lens insertion zone (estimated via slit lamp beam length). Ocular, systemic health, and lifestyle data were collected via comprehensive exam and questionnaire. Multivariate regression was used to assess the relationship between IOP (Goldmann) and LAZ. Results There were 2169 non-LAZ and 129 LAZ subjects (mean age: 49.8 ± 15.0 vs. 62.6 ± 10.2 years; 63.6% vs. 76.0% female; 83.2% vs. 91.5% African American). Right eyes with >trace LAZ (n = 59 of 110) had higher unadjusted mean IOP than control eyes (16.4 ± 3.3 vs. 15.0 ± 3.3 mm Hg, P = 0.005), and with control for numerous factors, LAZ eyes had an average IOP of approximately 1.3 ± 0.4 mm Hg higher (P = 0.003) than non-LAZ eyes. Final model covariates included sex (P = 0.001); spherical-equivalent refractive error (D; P < 0.0001); body mass index (kg/m2; P < 0.001); presence of diabetes (P < 0.001); having >high school education (P < 0.001); systolic blood pressure (mm Hg; P < 0.0001); being an ever smoker (P = 0.006); and having history of any site cancer (P = 0.01). Conclusions The LAZ trait, with potential prevalence near 2%, was associated with a higher IOP. This observation is consistent with the hypothesis that the trait is a marker for underlying mechanisms that elevate glaucoma risk.

We have established a flow cytometry‐based Pig‐a assay for rat bone marrow erythroid cells (BMEs). The BME Pig‐a assay uses a DNA‐specific stain and two antibodies: one against the transmembrane transferrin receptor (CD71 marker) and the other against the GPI‐anchored complement inhibitory protein (CD59 marker). In F344 male rats treated acutely with a total of 120 mg/kg of N‐ethyl‐N‐nitrosourea (ENU) the frequency of CD59‐deficient phenotypically mutant BMEs increased approximately 24‐fold compared to the rats concurrently treated with the vehicle. Such an increase of mutant BMEs coincides with increases of CD59‐deficient reticulocytes measured in rats treated with similar doses of ENU. Sequence analysis of the endogenous X‐linked Pig‐a gene of CD59‐deficient BMEs revealed that they are Pig‐a mutants. The spectrum of ENU‐induced Pig‐a mutations in these BMEs was consistent with the in vivo mutagenic signature of ENU: 73% of mutations occurred at A:T basepairs, with the mutated T on the nontranscribed strand of the gene. T→A transversion was the most frequent mutation followed by T→C transition; no deletion or insertion mutations were present in the spectrum. Since BMEs are precursors of peripheral red blood cells, our findings suggest that CD59‐deficient erythrocytes measured in the flow cytometric erythrocyte Pig‐a assay develop from BMEs containing mutations in the Pig‐a gene. Thus, the erythrocyte Pig‐a assay detects mutation in the Pig‐a gene. Environ. Mol. Mutagen. 59:722–732, 2018. © 2018 Wiley Periodicals, Inc.

People with the long anterior zonule (LAZ) trait, which may have prevalence near 2%, have zonular fibers that extend more central than usual along the anterior capsule of the crystalline lens. The anomalous fibers can be observed in vivo with clinical slit lamp biomicroscopy after pharmacologic pupil dilation, and although minimally studied, the LAZ trait may have importance to glaucoma, retinal degeneration, and cataract surgery. To further characterize LAZ morphology, a custom computer program was used to trace LAZ fibers seen on retro‐illumination photos acquired during previous study at an academic, urban eye care facility in Chicago, IL. There were 59 African‐Americans (54 female; median age = 70 years, 53–91 years) included in the analysis. After initial review of the zonule tracings, we identified three basic LAZ patterns. We called one pattern (47% of right eyes) a “non‐segmental LAZ pattern,” which was predominated by fibers that could be visually traced to the dilated pupil border where they became obscured by the iris. Another pattern (35% of right eyes), the “segmental LAZ pattern,” was predominated by fibers that appeared to terminate abruptly without detectable extension to the pupil border. The third pattern (18% of right eyes), the “mixed LAZ pattern,” had a more equivalent mixture of the other two fiber morphologies. Compared to the “non‐segmental” group, the “segmental” LAZ eyes had smaller central zonule‐free zones (P < 0.0001), and they tended to exhibit fewer LAZ fibers (P = 0.07). These data improve understanding of LAZ clinical anatomy and may be helpful to future investigation. Anat Rec, 300:1336–1347, 2017. © 2017 Wiley Periodicals, Inc.

Long anterior lens zonules (LAZ) are characterized by zonular fibres, often pigmented, that extend more central than usual on the anterior lens capsule, sometimes causing marked reduction in the zonule-free zone (ZFZ) (Fig. 1).1 One LAZ variety occurs with genetic mutation and late-onset macular degeneration.2 Another type, which may have a prevalence near 2%, has unknown etiology and association with age >50 years, female gender, hyperopia, shorter axial length, and persistent pupillary iris strands.3 LAZ have received attention due to possible association with open- and narrow-angle forms of glaucoma4 and due to concern that their cutting may cause capsular tearing following cataract surgery.1 Normal zonules versus long anterior lens zonules (LAZ) (top left). Retro-illumination images of pupil with different light positions and example lens optic section photo used to calculate ratio of pupil diameter to visible iris diameter (top right). LAZ tracing of nasal/temporal halves of intra-pupillary lens, and halves merged and overlaid onto the pupil zone for illustrational purposes. Zonule-free zone (ZFZ) borders are based on tip of most anterior extending zonule. Final ZFZ is based on smaller half circle (bottom left). Number of LAZ plotted against ZFZ size. Plot includes least squares regression line with 95% confidence limits (bottom right). To further characterize the LAZ trait, we quantified LAZ and their ZFZs using subjects from a prior study who had extensive testing and standardized documentation that included post-dilation retro-illumination photos (16×) of the anterior capsule.4 To view the entire intra-pupillary lens without obscuration, photos were taken with light beams just inside the temporal and nasal pupil borders. We then developed a custom program (MATLAB 6.1, The MathWorks, Inc., Natick, MA, USA) to merge unobstructed image halves and enhance LAZ for mapping (Fig. 1). One observer (CM), masked to subjects, reviewed randomized images and marked the anterior tip and peripheral tip of each LAZ fibre, which was often limited by the pupil border (Fig. 1). Two other observers (TN, DKR) reviewed tracings before acceptance. Fibre counts and meridians were then calculated. For all subjects who had acceptable lens optic section photos at the time of the retro-illumination photos, ZFZ diameters were estimated from “pupil to visible iris diameter” ratios in relation to different diameter assumptions, that is, 11.5, 12.0 and 12.5 mm.5 Three sizes were used to provide sensitivity analysis. Another masked observer (SF) determined the ratios using software (EyeCap SL, V3) provided with the Haag-Streit BX900 photo slit lamp (Haag-Streit AG, Koeniz, Switzerland). Our analyses found that number of LAZ varied greatly, with many subjects having relatively few LAZ (Table 1). We also found a predilection for superior quadrants (Fig. 2). Mappings highlighted a propensity for fibres to extend more centrally in some clock hours than others, and estimations indicated that 50% of eyes had ZFZs ≤3.0 mm in diameter. We did not detect any relationship between ZFZ size and number of LAZ, age or refractive error (P > 0.1). Number of LAZ also did not vary significantly with age or refraction (Fig. 2). Although we did not find the highest number of LAZ in the oldest subjects, it is interesting that we have rarely detected LAZ in people <50 years of age.4 The reason for this remains unknown, and since LAZ are often non-pigmented, better visibility from pigmentation does not adequately explain their detection in later years. Since we did not find significant variation of ZFZ with age, this also suggests that ZFZ size might be established early after LAZ become clinically apparent. TOTAL SUBJECTS† N = 59 (54 female, 5 male) §Mean Age = 70.6 ± 9.0 years (53–91 years) Graph showing long anterior lens zonules (LAZ) predilection for superior quadrant (INF, inferior; NAS, nasal; SUP, superior; TEMP, temporal) (top left). Number of LAZ and zonule-free zone (ZFZ) size plotted against age. Plots include least squares regression lines with 95% confidence limits (top, bottom right). Histogram showing distribution of ZFZ diameters (bottom left). The tracings highlighted a peculiar feature of LAZ, that is, a “segmental” appearance in which fibres end abruptly without visible extension all the way peripherally (Fig. 1). Why this happens remains unexplained, but determining its reason might improve knowledge of lens/zonule physiology. In total, these data help further characterize the LAZ trait, which remains understudied, given its suggested prevalence, potential relationship to glaucoma and macular degeneration, and importance relative to cataract surgery. The authors thank Dr. Sarah Fong for technical assistance provided during components of this investigation.