Intraocular lens calculations in patients with keratoectatic disorders.

PURPOSE OF REVIEW: Intraocular lens (IOL) calculations in patients with keratoconus and other keratoectatic disorders continues to be a challenge for today's cataract surgeon. In this article, we review data published over the past 18 months (June 2018 to January 2020). RECENT FINDINGS: Cataract surgery in keratoconus patients has the potential to greatly improve patients' vision. However, keratoconic eyes are notorious for unpredictable outcomes because of difficulty in obtaining proper preoperative biometry and lack of data and consensus on IOL calculation formulas that can reliable in providing the desired outcome. Recent studies suggest the Barrett II Universal calculation is the most accurate in mild-to-moderate keratoconic eyes. All studies note the level of predictability decreases with the steepness of keratometric readings. Historically, the SRK/T has been shown to provide the most reliable calculations. SUMMARY: There is still no consensus on which formula is best for IOL calculation in keratoconic eyes. On the basis of the most recent literature, we recommend using the Barrett II Universal in conjunction with the SRK/T formula for mild-to-moderate eyes. Preoperative counseling of expectations with the patient is the key to achieving a satisfied patient and avoiding an unpleasant situation in the result of refractive surprise.

Promoting microbial utilization of phenolic substrates from bio-oil.

The economic viability of the biorefinery concept is limited by the valorization of lignin. One possible method of lignin valorization is biological upgrading with aromatic-catabolic microbes. In conjunction, lignin monomers can be produced by fast pyrolysis and fractionation. However, biological upgrading of these lignin monomers is limited by low water solubility. Here, we address the problem of low water solubility with an emulsifier blend containing approximately 70 wt% Tween® 20 and 30 wt% Span® 80. Pseudomonas putida KT2440 grew to an optical density (OD600) of 1.0 ± 0.2 when supplied with 1.6 wt% emulsified phenolic monomer-rich product produced by fast pyrolysis of red oak using an emulsifier dose of 0.076 ± 0.002 g emulsifier blend per g of phenolic monomer-rich product. This approach partially mitigated the toxicity of the model phenolic monomer p-coumarate to the microbe, but not benzoate or vanillin. This study provides a proof of concept that processing of biomass-derived phenolics to increase aqueous availability can enhance microbial utilization.

Damage to the microbial cell membrane during pyrolytic sugar utilization and strategies for increasing resistance.

Lignocellulosic biomass is an appealing feedstock for the production of biorenewable fuels and chemicals, and thermochemical processing is a promising method for depolymerizing it into sugars. However, trace compounds in this pyrolytic sugar syrup are inhibitory to microbial biocatalysts. This study demonstrates that hydrophobic inhibitors damage the cell membrane of ethanologenic Escherichia coli KO11+lgk. Adaptive evolution was employed to identify design strategies for improving pyrolytic sugar tolerance and utilization. Characterization of the resulting evolved strain indicates that increased resistance to the membrane-damaging effects of the pyrolytic sugars can be attributed to a glutamine to leucine mutation at position 29 of carbon storage regulator CsrA. This single amino acid change is sufficient for decreasing EPS protein production and increasing membrane integrity when exposed to pyrolytic sugars.

Impact of biochar-based slow-release N-fertilizers on maize growth and nitrogen recovery efficiency.

Biochar has been used to address several environmental problems and may be efficacious as a carrier of N-fertilizer in slow-release N-fertilizer (SRF) formulations. Our objective was to compare the efficacy of SRF pellets formulated with different mass ratios of biochar and urea with traditional N-fertilizers for improving N use efficiency by maize (Zea mays L.) grown under greenhouse conditions. Two different soil types, four SRF formulations with different biochar-to-urea (BCN) ratios (1:2 BCN, 1:3 BCN, 1:4 BCN, and 1:6 BCN), three traditional N-fertilizers (urea, urea ammonium nitrate, and S-coated urea), and unfertilized controls for each soil were tested. The accelerated urea release test showed significantly less loss of urea for the SRF over time than the traditional N-fertilizers. The biochar-based SRF formulations significantly (p < 0.05) decreased nitrate leaching loss for both soils relative to the traditional fertilizers. All the SRF formulations increased maize shoot (1%-34%) and root (0%-23%) biomass, N-recovery efficiency (17%-50%), and soil potential mineralizable-N relative to urea and S-coated urea. The results also indicate that the BCN ratio in the SRF formulation can be used to influence the timing of N release and plant N uptake. The results of the greenhouse study suggest that biochar-based SRFs have potential agronomic and environmental benefits; however, more research is needed to assess their agronomic value under field conditions.

Risk Factors for Meibomian Gland Disease Assessed by Meibography.

Purpose: To elucidate risk factors for meibomian gland disease (MGD) and understand associated changes in meibography and in relation to ocular surface disease. Patients and Methods: As part of the standard workup for ocular surface disease at a tertiary academic center, 203 patients received an ocular history and lifestyle questionnaire. The questionnaire included detailed inquiries about ocular health and lifestyle, including makeup use, cosmetic eyelid procedures, screen time, and contact lens habits. Subjects also took the standardized patient evaluation of eye dryness (SPEED) II questionnaire. Meibomian gland (MG) dropout and structural changes were evaluated on meibography and scored by three independent graders using meiboscores. Statistical analysis was conducted to identify significant risk factors associated with MG loss. Results: This retrospective, cross-sectional study included 189 patients (378 eyes) with high-quality images for grading, and the average age was 67 years (77% female). Patients older than 45 years had significantly more dropout than younger patients (p < 0.01). Self-reported eye makeup use did not significantly impact MG loss. Patients with a history of blepharoplasty trended toward higher meiboscores, but the difference was not statistically significant. Self-reported screen time did not affect meiboscores. Contact lens use over 20 years was associated with significant MG loss (p < 0.05). SPEED II scores had no relationship to meiboscores (p = 0.75). Conclusion: Older age is a significant risk factor for MG loss. Any contact lens use over 20 years also impacted MG dropout. Highlighting the incongruence of symptoms to signs, SPEED II scores showed no relationship to the structural integrity of MGs.

One-Year Outcomes From a Prospective, Randomized, Eye-to-Eye Comparison of Wavefront-Guided and Wavefront-Optimized PRK in Myopia.

PURPOSE: To compare wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) in patients with myopia using objective and self-reported quality of vision outcomes. METHODS: A total of 40 eyes from 20 participants were prospectively randomized to receive WFG or WFO PRK with the WaveLight Allegretto Eye-Q 400-Hz excimer laser (Alcon Laboratories, Inc., Fort Worth, TX). The primary outcome measured was uncorrected distance visual acuity (UDVA) at 12 months postoperatively. Secondary outcome measures included corrected distance visual acuity (CDVA), less than 5% and less than 25% contrast visual acuity, changes in higher order aberrations (HOAs), and self-reported quality of vision. Patients completed a validated, Rasch-tested, linear-scaled 30-item questionnaire assessing the quality of vision and visual symptoms preoperatively and at each visit. RESULTS: There was no statistically significant difference (P > .05) between the WFG and WFO groups in the frequency of attaining a refractive error within ±0.25 diopters of emmetropia, achieving postoperative UDVA of 20/16 or better or 20/20 or better, losing one or two or more lines or maintaining their preoperative CDVA, or differences in UDVA, CDVA, low contrast acuity, or HOAs. None of the measured quality of vision parameters exhibited statistically significant differences between the groups preoperatively or at 12 months postoperatively (all P > .05). The WFG and WFO groups each showed significant improvement in multiple subjective measures compared to pretreatment values in the same eye. A total of 12.5% of patients preferred their WFG PRK eye, 31.25% preferred their WFO PRK eye, and 56.25% had no preference at 12 months postoperatively. CONCLUSIONS: WFG and WFO PRK using the Alcon Wave-Light Allegretto Eye-Q 400-Hz excimer laser platform provide similar results and self-reported visual symptoms in myopic eyes at 12 months postoperatively. [J Refract Surg. 2020;36(3):160-168.].

Scleral fixation of intraocular lenses using Gore-Tex suture: clinical outcomes and safety profile.

BACKGROUND/AIMS: To report the short-term safety profile and clinical outcomes of scleral fixation of intraocular lenses (IOLs) using Gore-Tex suture. METHODS: Retrospective, interventional case series. 85 eyes of 84 patients undergoing ab externo scleral fixation of a Bausch and Lomb Akreos AO60 or Alcon CZ70BD IOL using Gore-Tex suture. Primary outcome measures were change in visual acuity and occurrence of intraoperative and postoperative complications with minimum follow-up of 90 days. RESULTS: 85 eyes of 84 patients were identified. Mean logarithm of the minimum angle of resolution visual acuity improved from 1.43±0.72 (20/538 Snellen equivalent) preoperatively to 0.64±0.61 (20/87 Snellen equivalent) postoperatively (p<0.001). Mean follow-up was 325 days (median 264 days, range 90-996 days). There were no intraoperative complications noted. Postoperative complications included hypotony in eight patients (9.4%), ocular hypertension in six eyes (7%), vitreous haemorrhage in six eyes (7%), hyphema in two eyes (2%), serous choroidal detachment in two eyes (2%), cystoid macular oedema in two eyes (2%) and corneal oedema in one eye (1%). There were no cases of postoperative endophthalmitis, suture erosion/breakage, retinal detachment, suprachoroidal haemorrhage, uveitis-glaucoma-hyphema syndrome or persistent postoperative inflammation in the follow-up period. CONCLUSIONS: Ab externo scleral fixation of IOLs with Gore-Tex suture was well tolerated in all cases. No suture-related complications were encountered. This procedure led to improvement in visual acuity and was not associated with significant intraoperative or postoperative complications.

Production of clean pyrolytic sugars for fermentation.

This study explores the separate recovery of sugars and phenolic oligomers produced during fast pyrolysis with the effective removal of contaminants from the separated pyrolytic sugars to produce a substrate suitable for fermentation without hydrolysis. The first two stages from a unique recovery system capture "heavy ends", mostly water-soluble sugars and water-insoluble phenolic oligomers. The differences in water solubility can be exploited to recover a sugar-rich aqueous phase and a phenolic-rich raffinate. Over 93 wt % of the sugars is removed in two water washes. These sugars contain contaminants such as low-molecular-weight acids, furans, and phenols that could inhibit successful fermentation. Detoxification methods were used to remove these contaminants from pyrolytic sugars. The optimal candidate is NaOH overliming, which results in maximum growth measurements with the use of ethanol-producing Escherichia coli.

Implementation and evaluation of an incentivized Internet-mediated walking program for obese adults.

In response to rising health care costs associated with obesity rates, some health care insurers are adopting incentivized technology-enhanced wellness programs. The purpose of this study is to evaluate the large-scale implementation of an incentivized Internet-mediated walking program for obese adults and to examine program acceptance, adherence, and impact. A mixed-methods evaluation was conducted to investigate program implementation, acceptance, and adherence rates, and physical activity rates among program participants. Program implementation was shaped by national and state policies, data security concerns, and challenges related to incentivizing participation. Among 15,397 eligible individuals, 6,548 (43 %) elected to participate in the walking program, achieving an average of 6,523 steps/day (SD 2,610 steps). Participants who uploaded step counts for 75 % of days for a full year (n = 2,885) achieved an average of 7,500 steps (SD 3,093). Acceptance and participation rates in this incentivized Internet-mediated walking program suggest that such interventions hold promise for engaging obese adults in physical activity.

Exercise hypertension: an adverse prognosis?

We sought to clarify the prognostic importance of an "exaggerated" or "hypertensive" systolic blood pressure response to exercise during an exercise test. Studies evaluating the prognosis for cardiovascular events and cardiovascular mortality in those with hypertension during exercise testing were systematically reviewed. Fourteen studies were identified. Six studies were of healthy volunteers or hypertensives. Eight studies were in subjects with known or suspected heart disease. Without established heart disease, exercise hypertension predicted cardiovascular events and cardiovascular death. However, two of the six studies included a multivariate analysis; both demonstrated no independent association. Studies in subjects with known or suspected heart disease demonstrated that exercise hypertension predicted fewer cardiac events and lesser mortality or, after multivariate adjustment, no associated risk. In a healthy population, a higher exercise blood pressure may indicate hypertension or prehypertension, instead of normal vascular function, and an associated long-term adverse prognosis. In a population with a high burden of heart disease, the highest risk subjects with the most extensive cardiac disease may not be capable of generating pressure or workload to allow the manifestation of exercise systolic hypertension. By comparison, therefore, those with exercise hypertension have a better prognosis.