Refractive surgical approaches to keratoconus: A systematic review and network meta-analysis

Advancements in diagnostic methods and surgical techniques for keratoconus (KC) have increased non-invasive treatment options. Successful surgical planning for KC involves a combination of clinical science, empirical evidence, and surgical expertise. Assessment of disease progression is crucial, and halting the progression should be the focus if it is progressive. While surgeons used to rely on experience alone to decide the surgical method, comparing the network of primary factors, such as visual acuity, across studies can help them choose the most appropriate treatments for each patient and achieve optimal outcomes. Meticulous tabulation methods facilitate interpretation, highlighting the importance of selecting the correct surgical and rehabilitation approach based on each patient's condition and stage of the disease. We detail the outcomes of a comprehensive network meta-analysis comparing the effectiveness of various combined therapeutic refractive treatments for KC at identical stages of the disease, spanning four distinct follow-up intervals. Additionally, the comprehensive analysis suggests that for corneas with optimal best corrected visual acuity (BCVA) preoperatively (classified as regular), combining phakic intraocular lenses with intracorneal ring segments (ICRS) and corneal cross-linking (CXL) could offer the best therapeutic approach provided the disease stage does not exceed stage 3. For irregular corneas, although initial follow-ups show a significant difference in BCVA with surface ablation, longer-term follow-ups recommend combining surface ablation with ICRS and CXL, especially at higher stages.

Comparison of different corneal imaging modalities using artificial intelligence for diagnosis of keratoconus: a systematic review and meta-analysis

PURPOSE

This review was designed to compare different corneal imaging modalities using artificial intelligence (AI) for the diagnosis of keratoconus (KCN), subclinical KCN (SKCN), and forme fruste KCN (FFKCN).

METHODS

A comprehensive systematic search was conducted in scientific databases, including Web of Science, PubMed, Scopus, and Google Scholar based on the PRISMA statement. Two independent reviewers assessed all potential publications on AI and KCN up to March 2022. The Critical Appraisal Skills Program (CASP) 11-item checklist was used to evaluate the validity of the studies. Eligible articles were categorized into three groups (KCN, SKCN, and FFKCN) and included in the meta-analysis. The pooled estimate of accuracy (PEA) was calculated for all selected articles.

RESULTS

The initial search yielded 575 relevant publications, of which 36 met the CASP quality criteria and were included in the analysis. Qualitative assessment showed that Scheimpflug and Placido combined with biomechanical and wavefront evaluations improved KCN detection (PEA, 99.2, and 99.0, respectively). The Scheimpflug system (92.25 PEA, 95% CI, 94.76-97.51) and a combination of Scheimpflug and Placido (96.44 PEA, 95% CI, 93.13-98.19) had the highest diagnostic accuracy for the detection of SKCN and FFKCN, respectively. The meta-analysis outcomes showed no significant difference between the CASP score and accuracy of the publications (all P > 0.05).

CONCLUSIONS

Simultaneous Scheimpflug and Placido corneal imaging methods provide high diagnostic accuracy for early detection of keratoconus. The use of AI models improves the discrimination of keratoconic eyes from normal corneas.

Insight into small eyes: a practical description from phenotypes presentations to the management

This narrative review aimed to have an algorithmic approach to microphthalmos by a systematic search. The definition can be related to a number of special phenotypes. In the more challenging cases of complex microphthalmos, relative anterior microphthalmos, and nanophthalmos, the surgeon can approach these cases more safely if they have a deep understanding of the anatomical variations and ideal formulae for intraocular lens computation and knows how to avoid intra- and post-operative complications. In this article, we review the criteria by which we recognize and describe pre-, intra-, and post-operative considerations, as well as discuss the ideal intraocular lenses for microphthalmos, given the intricate varieties of small eye phenotypes.

Association between obesity and age-related cataract: an updated systematic review and dose-response meta-analysis of prospective cohort studies

Objective

There are inconsistent findings on the association between obesity and age-related cataract (ARC). This systematic review was done to summarize available findings on the association between obesity [defined by body mass index (BMI)] and ARC by performing a dose-response meta-analysis on eligible prospective cohort studies.

Methods

We performed a systematic search in PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until June 2022 to identify eligible publications.

Results

In total, 16 studies with a total sample size of 1,607,125 participants were included. Among all of these studies, there were 103,897 cases of ARC. In the follow-up periods ranging between 4 and 28 years, 4,870 cases of nuclear cataract, 1,611 cases of cortical cataract, and 1,603 cases of posterior subcapsular cataracts (PSC) were detected. By comparing the highest and lowest categories of BMI, we found that higher BMI was associated with an increased risk of ARC (RR: 1.18, 95% CI: 1.09-1.28) and PSC (RR: 1.44, 95% CI: 1.08-1.90). In the dose-response analysis, each 5 kg/m2 increase in BMI was associated with a 6 and 27% increased risk of ARC (RR: 1.06, 95% CI: 1.01-1.12) and PSC (RR: 1.27, 95% CI: 1.14-1.41), respectively. In addition, we found a positive association for cortical cataract among high-quality studies, in which higher BMI was associated with a 20% increased risk of cortical cataract (RR: 1.20, 95% CI: 1.02-1.42). In terms of nuclear cataract, we found no significant association either in the comparison between the highest and lowest categories of BMI or in the dose-response meta-analysis.

Conclusion

Obesity (defined by BMI) was associated with an increased risk of ARC, PSC, and cortical cataract in adults. However, such a positive association was not seen for nuclear cataract.

PROSPERO registration

CRD42022357132.

Biomechanical changes in keratoconus after customized stromal augmentation

PURPOSE

To verify corneal biomechanical changes, poststromal augmentation using myopic small-incision lenticule extraction's (SMILEs) lenticules in advanced keratoconus (KCN) through Corvis ST (Oculus, Wetzlar, Germany).

MATERIALS AND METHODS

A clinical trial enrolled 22 advanced KCN patients. We implanted lenticules exceeding 100 μ according to a nomogram and evaluated biomechanical factors through Corvis ST at 3-, 6-, and 24-month postimplantation. We examined parameters during the first applanation (A1), second applanation (A2), highest concavity (HC)/max concavity events, and Vinciguerra screening parameters, as recently established criteria derived from the ideal blend of diverse biomechanical and ocular factors and formulated through the application of logistic regression. Regression analyses explored relationships with age, mean keratometry value, thickness, sphere, cylinder, and best-corrected visual acuity.

RESULTS

Patients were well matched for age, intraocular pressure, and central corneal thickness (CCT). The mean spherical equivalent decreased from -13.48 ± 2.86 Diopters (D) to -8.59 ± 2.17 D (P < 0.007), and mean keratometry decreased from 54.68 ± 2.77 D to 51.95 ± 2.21 D (P < 0.006). Significant increases were observed in HC time (HCT), Radius-central curvature radius at the HC state-, peak distance (PD) during HC state, CCT, first applanation time, and stiffness parameter (A1T and SP-A1), whereas HC deformation amplitude, maximum deformation amplitude ratio at 2 mm, Corvis Biomechanical Index (CBI), integrated radius (IR), second applanation deformation amplitude (A2DA), first applanation velocity and deflection amplitude (A1V and A1DeflA) significantly decreased postlenticule implantation. Multivariable regression revealed age positively correlated with SP-A1 (P = 0.003) and negatively with HC delta Arc length (P = 0.007). Mean K positively correlated with CCT (P = 0.05) and negatively with CBI (P = 0.032). Best-corrected visual acuity positively correlated with HCT (P = 0.044), and the cylinder positively correlated with PD (P = 0.05) and CCT (P = 0.05) whereas negatively with IR (P = 0.025).

CONCLUSIONS

Stromal augmentation using myopic SMILE lenticules induces significant corneal biomechanical changes in KCN.

Association of Patient Satisfaction with Cataract Grading in Five Types of Multifocal IOLs

INTRODUCTION

This study investigated patient satisfaction levels in five premium intraocular lenses (IOLs). A secondary aim was to determine whether patient satisfaction was associated with the cataract grade before lens surgery.

METHODS

In this multicenter prospective comparative study, 164 patients from diverse backgrounds underwent cataract surgery and were assigned for identical bilateral implantation of multifocal IOLs. In addition to visual performance, quality of life was measured using the National Eye Institute Refractive Error Quality Of Life Instrument (NEI-RQL 42) scoring questionnaire. The Sirius Scheimpflug Analyzer was used to evaluate the posterior cornea and aberrations. Finally, the association of patient satisfaction reports with the Pentacam Cataract Grading Scale (PCGS) and Lens Opacities Classification System (LOCS III) was evaluated.

RESULTS

A considerable subjective improvement was observed in uncorrected far, near (40 cm), and intermediate (60 cm) visual acuity in the five groups (P values < 0.001). A significant difference was observed in mesopic and photopic contrast sensitivity between Symfony, Trinova, and AT LISA at the spatial frequency of 12 cycles per degree, favoring Symfony (P < 0.001). PanOptix users had considerably lower mean coma values (P < 0.001), while AT LISA users had lower mean spherical aberrations (P = 0.009) compared to the other groups. No additional safety concerns relating to IOLs were recorded. Mean satisfaction had a high correlation with LOCS and Pentacam Nuclear Staging (PNS) in each lens group, e.g., correlation coefficient and P value for AT LISA were respectively r = 0.99, P < 0.001 and r = 0.97, P = 0.004.

CONCLUSION

Despite discrepancies between groups of lenses, most patients who received multifocal IOLs reported satisfaction at more than 3 years after the initial operation. A growing number of patients with cataracts are seeking spectacle-free vision with presbyopia-correcting IOLs. Hence, the high satisfaction rate among patients with cataract could indicate the value of offering a wider range of available lenses.

Main issues in deep anterior lamellar keratoplasty: A systematic narrative review

Deep anterior lamellar keratoplasty (DALK) has emerged as a transformative approach in managing corneal pathologies, notably keratoconus (KC), providing a viable alternative to penetrating keratoplasty (PK). This systematic review explores the intricacies of DALK, comparing its preoperative, intraoperative, and postoperative considerations with PK. Extensive literature searches revealed a wealth of data regarding DALK's advantages and challenges, with an emphasis on graft survival, visual outcomes, and complications. In the preoperative phase, DALK showcases its versatility, catering to a wide spectrum of patients, including those with KC and ocular surface disorders. Intraoperatively, it offers innovative techniques to address emphysema, bubble formation, and Descemet's membrane perforation, all while maintaining a strong focus on patient-centered outcomes. Postoperatively, DALK's lower rejection rates and decreased complications underscore its potential superiority over PK, although unique challenges such as graft failure from nonimmunologic factors demand vigilant management. This comprehensive review not only serves as a valuable resource for ophthalmic surgeons but also sheds light on the evolving landscape of corneal transplantation, highlighting DALK's role as a transformative force in the field.

Keratoconus: exploring fundamentals and future perspectives - a comprehensive systematic review

Background

New developments in artificial intelligence, particularly with promising results in early detection and management of keratoconus, have favorably altered the natural history of the disease over the last few decades. Features of artificial intelligence in different machine such as anterior segment optical coherence tomography, and femtosecond laser technique have improved safety, precision, effectiveness, and predictability of treatment modalities of keratoconus (from contact lenses to keratoplasty techniques). These options ingrained in artificial intelligence are already underway and allow ophthalmologist to approach disease in the most non-invasive way.

Objectives

This study comprehensively describes all of the treatment modalities of keratoconus considering machine learning strategies.

Design

A multidimensional comprehensive systematic narrative review.

Data sources and methods

A comprehensive search was done in the five main electronic databases (PubMed, Scopus, Web of Science, Embase, and Cochrane), without language and time or type of study restrictions. Afterward, eligible articles were selected by screening the titles and abstracts based on main mesh keywords. For potentially eligible articles, the full text was also reviewed.

Results

Artificial intelligence demonstrates promise in keratoconus diagnosis and clinical management, spanning early detection (especially in subclinical cases), preoperative screening, postoperative ectasia prediction after keratorefractive surgery, and guiding surgical decisions. The majority of studies employed a solitary machine learning algorithm, whereas minor studies assessed multiple algorithms that evaluated the association of various keratoconus staging and management strategies. Last but not least, AI has proven effective in guiding the implantation of intracorneal ring segments in keratoconus corneas and predicting surgical outcomes.

Conclusion

The efficient and widespread clinical translation of machine learning models in keratoconus management is a crucial goal of potential future approaches to better visual performance in keratoconus patients.

Trial registration

The article has been registered through PROSPERO, an international database of prospectively registered systematic reviews, with the ID: CRD42022319338.

Main issues in penetrating keratoplasty

This review explores contemporary challenges in penetrating keratoplasty (PK), focusing on technical intricacies, technological advancements, and strategies for preventing graft rejection. A systematic literature search from January 2018 to July 2023 was conducted across PubMed, Cochrane, Web of Science, Scopus, and EMBASE. The inclusion criteria comprised studies on PK and its comparison with other corneal pathologies, with emphasis on keratoconus (KC). Two independent reviewers screened studies, extracting relevant data. The review covers PK evolution, highlighting infra-red femtosecond lasers' impact on graft shapes, minimizing astigmatism, and enhancing wound healing. Graft rejection, a primary complication, is examined, detailing risk factors and preventive measures. Preoperative considerations, diagnostic techniques for rejection, and PK in KC are discussed. Postoperative care's significance, including intraocular pressure monitoring and steroid administration, is emphasized. The paper concludes with a comprehensive approach to prevent graft rejection, involving topical and systemic medications. An outlook on evolving monoclonal antibody research is presented. As the field progresses, personalized approaches and ongoing therapeutic exploration are expected to refine strategies, enhancing PK outcomes.

Cutting Edge: Corneal Stromal Lenticule Implantation (Corneal Stromal Augmentation) for Ectatic Disorders

ABSTRACT

The ectatic disease of the cornea poses a significant challenge for ophthalmologists because commonly used treatments to improve visual acuity, such as spectacles and contact lenses, may not be effective, especially in advanced stages. In addition, the preferred surgical management, corneal transplantation, has various issues related to tissue availability, the steep learning curve, and postoperative complications such as tissue stability and half-life. Ongoing research for an alternative to keratoplasty has suggested various methods, such as corneal crosslinking, which can improve visual function when combined with other techniques. Early reports have become available on the feasibility and safety of different strategies for corneal stromal augmentation, both with and without corneal crosslinking, and their favorable clinical outcomes, including visual and keratometry improvements. Here, we explore the cutting-edge advancements in stromal lenticule implantation, encompassing different facets of the procedure.

An Overview of Surgical Approaches for Lower Eyelid Blepharoplasty

Age-related changes in the lower eyelid are noticed by patients as bags or circles under the eye, a tired look, and a flattened face. Lower eyelid blepharoplasty, in which the excess skin and/or orbital fat is excised and repositioned, is mainly performed for aesthetic reasons rather than the correction of functional abnormalities. Favorable outcomes for the combination of these approaches have been reported, but the most suitable surgical technique is still debated. This systematic narrative review deals with the indications, preoperative considerations, operative techniques, and complications of several different surgical approaches to lower eyelid blepharoplasty.

LEVEL OF EVIDENCE: 3

Keratoconus Diagnosis: From Fundamentals to Artificial Intelligence: A Systematic Narrative Review

The remarkable recent advances in managing keratoconus, the most common corneal ectasia, encouraged researchers to conduct further studies on the disease. Despite the abundance of information about keratoconus, debates persist regarding the detection of mild cases. Early detection plays a crucial role in facilitating less invasive treatments. This review encompasses corneal data ranging from the basic sciences to the application of artificial intelligence in keratoconus patients. Diagnostic systems utilize automated decision trees, support vector machines, and various types of neural networks, incorporating input from various corneal imaging equipment. Although the integration of artificial intelligence techniques into corneal imaging devices may take time, their popularity in clinical practice is increasing. Most of the studies reviewed herein demonstrate a high discriminatory power between normal and keratoconus cases, with a relatively lower discriminatory power for subclinical keratoconus.

From Aesthetics and Soft Tissue Address to Visual Performance: A Multifaced Satisfaction Assessment by A Multicenter Study in Patients with Dermatochalasis

BACKGROUND

In this study, we seek to answer the question: does blepharoplasty for dermatochalasis alter visual performance?

OBJECTIVES

We seek to determine the extent of blepharoplasty's impact on visual performance (refraction, contrast sensitivity, and visual field) in subjects with dermatochalasis.

METHODS

A total of 146 eyelids of 74 patients, 48 (64.9%) females and 26 (35.1%) males ranging from 40 to 68 years old, with dermatochalasis were analyzed prospectively. Refraction, contrast sensitivity, visual acuity, higher-order aberrations (HOAs), and mean deviation index (MDI) in the Humphrey visual field were evaluated and recorded before and at 2, 4, and 6 months after upper eyelid blepharoplasty.

RESULTS

In the latest follow-up, uncorrected and corrected distance visual acuity showed no significant differences (P > .05). Patients' contrast sensitivity increased significantly at all spatial frequencies under both conditions (P < .05) except at 12 cycles per degree (cpd) in the photopic condition (P = .947). Mean astigmatism significantly decreased from -1.17 ± 0.83 to -0.89 ± 0.66, postoperatively (P ≤ .001). Total HOAs decreased significantly from 0.59 ± 0.13 μm to 0.51 ± 0.09 μm (P < .01) after surgery. The root mean square of the spherical aberration (P < .01), vertical trefoil (P = .018), horizontal trefoil (P < .01), horizontal coma (P < .001), and vertical coma (P < .01) decreased significantly. The MDI of the Humphrey visual field increased significantly postoperatively at all times compared with preoperatively (P < .05). Significant satisfaction (P < .001) by the Blepharoplasty Outcomes Evaluation (BOE) questionnaire had a favorable satisfaction with visual quality indexes.

CONCLUSIONS

Upper lid blepharoplasty, in addition to its aesthetic effect, is an effective intervention to promote visual function and quality of life.

Association of 2 Lysyl Oxidase Gene Single Nucleotide Polymorphisms with Keratoconus: A Nationwide Registration Study

Purpose

Keratoconus (KC) is the most common primary ectatic corneal disease, characterized by progressive thinning of the cornea, affecting its shape and structure and leading to visual loss. Lysyl oxidase is an important component of the extracellular matrix and contributes to the homeostasis of corneal stromal extracellular matrix via enzymatic reaction. This nationwide registration study aims to examine the association of KC with 2 known single nucleotide polymorphisms, rs2956540 and rs10519694, in a population of Iranian descent.

Design

Case-control.

Participants

One hundred seventy-eight subjects with KC and 180 clinically healthy subjects participated in the study.

Methods

Genomic DNA was extracted from peripheral blood samples, and their genotypes were determined using tetra-primer amplification refractory mutation system-polymerase chain reaction.

Main Outcome Measures

Allele frequency for rs2956540 and rs10519694.

Results

Genotype frequency was significantly different between cases and controls for rs2956540 (P value = 0.019). The rs2956540 C allele carriers were significantly more frequent among KC cases than healthy controls (P value_chi-square = 0.015, P value_{Fisher exact} = 0.017). There was a significant difference in genotype frequency between groups for rs10519694 (P value = 0.001). T allele carriers were significantly more frequent among KC patients (P value_chi-square = 0.002, P value_{Fisher exact} = 0.001). Sex stratification revealed no significant differences in genotype frequency between males and females in cases and controls. Fitting the general linear model showed that rs10519694 could be considered a predictor for the development of KC (P value = 0.001); however, this was not observed for rs2956540 (P value = 0.323).

Conclusions

rs2956540 and rs10519694 are associated with KC in a population of Iranian descent. rs10519694 could potentially be used for KC risk prediction.

Efficacy of Cysteamine and Methimazole in Treating Melasma A Comparative Narrative Review

Melasma is a chronic and acquired pigmentary condition that primarily affects women and undermines patient satisfaction and confidence. Melasma mostly affects females, accounting for 90% of all cases. It affects people of all races, particularly those with skin types IV and V who live in areas with lots of UV radiation. According to the studies, Melasma lesions are seen throughout the face in centrofacial, malar, and mandibular patterns. Melasma lesions on the forehead, cheeks, nose, upper lip, and/or chin are the most prevalent centrofacial pattern. Melasma lesions can also be detected along the periorbital area, especially in Asian people. Melasma is notably resistant to treatment, with many patients experiencing only temporary relief and relapses. Combining therapies that target numerous pathologic components, including photodamage, inflammation, aberrant vascularity, and abnormal pigmentation, generally results in the most dramatic therapeutic improvements. Treatments for dark circles include topical depigmenting medicines like hydroquinone, kojic acid, azelaic acid, and topical retinoic acid, and physical treatments such as chemical peels, surgical adjustments, and laser therapy. The objective of therapy should be to figure out what's causing the hyperpigmentation and what's contributing to it. This article provides an overview of melasma therapies and the efficacy of methimazole and cysteamine for melasma therapy.

Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM: To compare the visual results of non-topography-guided and topography-guided photorefractive keratectomy (PRK) applying sequential and simultaneous corneal cross-linking (CXL) treatment for keratoconus. METHODS: Interventional and comparative prospective study. Sixty-nine eyes (36 patients) suffering from keratoconus (stages 1 Amsler-Krumeich classification) were divided into four groups: sequential topography-guided photorefractive keratectomy with CXL, simultaneous topography-guided photorefractive keratectomy with CXL, simultaneous non-topography guided photorefractive keratectomy with CXL, and sequential non-topography guided photorefractive keratectomy with CXL. The main outcome measures were pre- and postoperative uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (CDVA), manifest refraction, contrast sensitivity, and keratometry. RESULTS: All analyzed visual, contrast sensitivity, and refractive parameters showed a significant improvement in the four groups (all P<0.05). A noticeable improvement was seen in keratometry in all the groups, and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups (P<0.05). Interestingly, the improvement in all parameters showed a degree of stability to the end of the follow-up. CONCLUSION: The treatment priorities in all four groups are safety, efficacy, and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus. No significant differences among groups in the recorded objective outcomes were found.

The Cardiac Effects of COVID-19: Review of articles

Cardiovascular wellbeing has been dramatically affected by severe acute respiratory syndrome coronavirus (SARS-CoV-2), the reason for the coronavirus disease pandemic 2019 (COVID-19) pandemic. There is a greater risk of morbidity and death in individuals with preexisting heart diseases. Clinical syndromes of the acute coronary syndrome, acute myocardial injury, myocarditis, arrhythmias, heart failure, and venous thromboembolism can, directly and indirectly, affect the heart. There may also be adverse heart effects of specific therapeutics under review for COVID-19. The renin-angiotensin-aldosterone system (RAAS) mechanism in virus replication makes it essential to understand the consequences of the system-modulating medications. For optimum patient care, detailed knowledge of specific cardiovascular symptoms of COVID-19 and the role of RAAS in the prognosis of COVID-19 disease is necessary.

Customized Stromal Lenticule Implantation for Keratoconus

PURPOSE

To investigate the potential benefit of keratoconus surgery using customized corneal stromal donor lenticules obtained from myopic small incision lenticule extraction (SMILE) surgery by femtosecond laser.

METHODS

In this prospective, consecutive, non-comparative series of cases, 22 lenticules were obtained from 22 myopic patients who had SMILE with a lenticule central thickness of greater than 110 µm. The lenticules were implanted in 22 eyes with advanced keratoconus. The lenticules were customized for the purpose of the implantation with either a simple necklace or necklace-with-ring shape (compound form) depending on the corneal thickness and corneal topography configuration of the implanted keratoconic eyes. The lenticules were implanted into a 9.5-mm corneal lamellar pocket created by the femtosecond laser. Changes in densitometry, thickness, confocal microscopy, corrected distance visual acuity (CDVA), and endothelial cell density were investigated.

RESULTS

Intrastromal lenticule implantation was successfully performed in all cases without any complication. Corneal thickness showed a mean enhancement of 100.4 µm at the thinnest point. On biomicroscopy, all corneas were clear at 1 year postoperatively and there was a significant improvement in corneal densitometry during the entire follow-up period. Confocal biomicroscopy showed collagen reactivation without any inflammatory features caused by the implanted fresh lenticules. CDVA improved from 0.70 to 0.49 logMAR (P = .001) and keratometry decreased from 54.68 ± 2.77 to 51.95 ± 2.21 diopters (P = .006).

CONCLUSIONS

Customized SMILE lenticule implantation by femtosecond laser proved to be feasible, resulting in an improvement in vision, topography, and refraction in the implanted eyes. [J Refract Surg. 2020;36(12):786-794.].

Visual performance of four types of diffractive multifocal intraocular lenses and a review of articles

AIM

To compare the clinical outcomes of a variety of multifocal intraocular lenses (MIOLs) in patients diagnosed with presbyopia or cataracts.

METHODS

This clinical trial study included 141 patients (282 eyes) with different MIOLs implantation. The Symfony (60 eyes), the ReSTOR (100 eyes), the AT LISAtri (60 eyes), and the PanOptix (62 eyes) intraocular lenses were evaluated in this prospective interventional study. The near, intermediate, and distant visual acuities, contrast sensitivity, and defocus curve were measured as valid criteria. To statistically analyze the results, we used the Statistical Package for Social Science software, the non-parametric Wilcoxon signed-rank t, the one-way analysis of variance and the Tukey's post-hoc test in our analysis. Moreover, we conducted a detailed literature search on the PubMed database in English about MIOLs, in total 59 studies were included in this review article.

RESULTS

The four approaches did not show any significant difference in the best-corrected distance visual acuity (P>0.05). The defocus curves at the contrast of 100% showed that trifocal IOLs had better intermediate performance than the bifocal IOL (P<0.05). There were no statistically significant differences between AT LISAtri and PanOptix lenses for visual acuity at all distances. The eyes with PanOptix, Symfony, and AT LISAtri IOL showed better contrast sensitivity than those ReSTOR at spatial frequencies of 1, 3, and 6 cpd in photopic and mesopic conditions (P<0.001).

CONCLUSION

All four groups of the multifocal lenses were satisfying in terms of distance and near vision. Also, the group of trifocal lenses led to satisfactory outcomes in intermediate vision, without degradation in quality of vision.

Detection of Angiotensin II and AT1 Receptor Concentrations in Keloid and Hypertrophic Scar

Background: Keloid and hypertrophic scars (HTS) are formed by excessive collagen formation. Angiotensin II, through the AT₁ receptor, plays an important role in extracellular matrix production. However, less is known about angiotensin II and AT₁ receptor concentrations in HTS and keloid tissues. Objective: The purpose of this study was to determine the angiotensin II and AT₁ receptor concentrations in keloid, HTS, and normal skin tissues. Methods: Skin biopsy samples from patients with HTS (n=26), keloid (n=20), and normal (n=30) skin tissues were evaluated for angiotensin II and AT₁ receptor concentrations by use of the enzyme-linked immunosorbent assay technique. Results: The angiotensin II concentration in patients with HTS was higher than that in the normal (P<0.0067) and keloid (P>0.9553) groups, while the AT₁ receptor concentration in patients with keloid was higher than that in the HTS (P<0.0001) and normal (P<0.0048) groups. Conclusion: Angiotensin II and AT₁ receptor concentrations could stimulate the formation of HTS and keloid. Angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors may be suitable compounds for the treatment of scar tissue.

Comparison of Visual, Refractive and Aberration Measurements of INTACS versus Toric ICL Lens Implantation; A Four-year Follow-up

This study was performed to evaluate the visual, refractive, and aberration measurement results of 2 implants, including Intacs Intracorneal Ring Segments (ICRS) and phakic Toric Implantable Collamer Lens (TICL), in patients with moderate Keratoconus (KCN). In this retrospective cross-sectional study, 30 patients with KCN with a mean age of 29.83 years were included in 2 groups, including the Intacs Intracorneal Ring Segments (ICRS) group and the phakic Toric Implantable Collamer Lens (TICL) group. Preoperative data as well as 6-month, 1-, 2-, 3- and 4-year follow-up data after the operation were collected and analyzed with the SPSS software (ver. 23.0, SPSS, Inc., Chicago, IL), using the paired t-test, independent t-test, repeated measures Analysis of Variance (ANOVA), and one-way ANOVA. This study included 30 patients with KCN with a mean age of 29.83 years and range of 25 to 35 years, including 17 males with a mean age of 30.11 years and 13 female with a mean age of 29.25 years. Except for preoperative Uncorrected Distance Visual Acuity (UCDVA), Spherical Equivalent (SE) and astigmatism, there was a significant difference between the 2 groups regarding other variables. The TICL group had a significantly better UCDVA and Best Corrected Distance Visual Acuity (BCDVA) in all post-operative follow-ups, and SE and astigmatism values were significantly lower in all post-operative follow-ups when compared with the ICRS group. There was a significant reduction in corneal and total coma as well as internal trefoil aberrations (P<0.01, P<0.01, and P=0.014, respectively) in the ICRS group, and TICL led to a significant reduction in internal trefoil aberration with P<0.03. Comparison of the 2 groups revealed a significant difference in corneal spherical (P<0.01) and total coma (P=0.02) aberrations and no significant differences in other HOA. Both ICRS and TICL are useful in patients with moderate KCN. However, TICL appears to have more stable and predictable vision results.

Implantation of ArtificialIris, a CustomFlex irisprosthesis, in a trauma patient with an Artisan lens: A case report and review

PURPOSE

To evaluate probable complications of ArtificialIris implantation with iris fixated intraocular lens.

METHOD

Development of photophobia, glare, and psychological strain during face-to-face communication in a 23-year-old man with a widespread traumatic iris defect terminate to make a decision for performing implantation of an ArtificialIris (Humanoptics, Erlangen, Germany) under the remnant iris without removing the patient's existing Artisan lens.

RESULTS

Without any intraoperative or postoperative complications, the patient's visual acuity increased by 1 line, the endothelial cell loss was comparable with the cell loss associated with standard cataract surgery, and the anterior-chamber depth and anterior-chamber anatomy did not change. At the final follow-up examination, the mean intraocular pressure did not differ from baseline, and we achieved high level of patient satisfaction and subjective vision improvement. We discuss the particular importance of considering the patient's expectations, the appropriate measurements, ways to perfect color evaluation, and the types of ArtificialIris products.

CONCLUSION

The implantation of the ArtificialIris in patients with aphakic iris-supported lenses (ie, pre-existing Artisan lenses) is a feasible approach and a useful option for patients with thin irises and iris hypoplasia who are at risk of subluxation or the dislocation of the posterior-chamber intraocular lens (PCIOL), and also those with sclerally fixed PCIOLs.

Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation)

Aims

To report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation).

Methods

Forty eyes of 24 patients with stable keratoconus with myopia between 0.00 and −18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications.

Results

At 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500–711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery.

Conclusion

The results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus.

Trial registration number

NCT02833649, Pre-results

Detection of DNA by scraping the formalin-fixed paraffin-embedded tissue

BACKGROUND

Pakistan is a developing country and most of the research laboratories have limited required infrastructures for the diagnosis of cancer at molecular level. The polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded tissues is becoming a popular procedure in the research centres. The study was conducted to introduce two new methods of DNA extraction for the PCR from formalin-fixed paraffin-embedded sections of surgical pathology specimens.

MATERIALS AND METHODS

Two methods of DNA detection were used. In method A the formalin-fixed tissues were grossed, proper sections were taken, processed in an automatic tissue processor, embedded in paraffin blocks, and microtomic sections were made. In method B, the procedure was the same until embedding in the paraffin blocks, after which the selected paraffin blocks were set on a black card paper (4 cm x 4 cm) and 1 mg of pure scraped tissue was obtained using a scalpel, manually without using microtone.

RESULTS

DNA was successfully extracted but point mutation of p53 gene was not seen in SCP while it was determined in 96 and 93.75 per cent cases of SCC by method A and method B respectively. There was no statistical difference in the results by both methods (P = 0.359).

CONCLUSION

Scraping of the tissue for DNA detection was a simple method and may be performed in any laboratory. The reliability, reproducibility, and quality assurance of the present results are consistent with the already established techniques of DNA extraction for PCR.

Long-term outcome and objective changes of anorectal function after biofeedback therapy for faecal incontinence

BACKGROUND

In the short-term, biofeedback therapy improves symptoms and anorectal function in patients with faecal incontinence but whether there is long-term improvement is incompletely understood.

AIM

To prospectively evaluate bowel symptoms and anorectal function, both immediately and 12 months after biofeedback therapy.

METHODS

A total of 105 consecutive patients (male/female = 12/93) with faecal incontinence, unresponsive to supervised medical treatment were enrolled in biofeedback training consisting of biweekly pelvic muscle strengthening exercises, anal squeeze and sensory-motor coordination training, and reinforcement sessions at 3, 6 and 12 months. Anorectal manometry, saline continence test, stool diaries and bowel satisfaction scores were used to assess improvement.

RESULTS

94/105 (male/female = 10/84) completed training and 11 dropped out. Sixty completed 1-year assessment. At 1-year, 63% reported no episodes of incontinence. Biofeedback decreased (P < 0.001) stool frequency and number of incontinence episodes and increased (P < 0.001) bowel satisfaction score, anal resting and squeeze pressures, squeeze duration and ability to retain saline infusion increased (P < 0.001), both immediately and at 1 year. Sensory thresholds decreased (P < 0.001).

CONCLUSIONS

Biofeedback therapy produced sustained improvement in bowel symptoms and anorectal function. Because it is safe, inexpensive compared with other surgical interventions, and effective, biofeedback should be offered to incontinent patients unresponsive to medical therapy.

The gene for cherubism maps to chromosome 4p16

Cherubism is an autosomal dominant disorder that may be related to tooth development and eruption. It is a disorder of age-related bone remodeling, mostly limited to the maxilla and the mandible, with loss of bone in the jaws and its replacement with large amounts of fibrous tissue. We have used a genomewide search with a three-generation family and have established linkage to chromosome 4p16. Three other families affected with cherubism were also genotyped and were mapped to the same locus. The combined LOD score is 4.21 at a recombination fraction of 0, and the locus spans an interval of approximately 22 cM.

Effect of acute water deprivation on renal function in rats

The effect of acute water deprivation for 96 h on renal function was studied in male Sprague-Dawley rats. The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were estimated using inulin and p-amino hippuric acid (PAH), respectively, as model compounds. Acute water deprivation caused a significant decrease (44 per cent) in the GFR without altering the ERPF. These results indicate that a proper dosage adjustment may have to be made in the dehydration condition, especially for drugs whose disposition is dependent on GFR.

Influence of water deprivation on the disposition of paracetamol

The effect of acute (96 h) water deprivation on the disposition of paracetamol (acetaminophen) has been examined in male Sprague-Dawley rats. Plasma and urinary concentrations of the drug and its two major metabolites, the glucuronide and sulphate, were determined by a sensitive and specific high performance liquid chromatographic assay. Following an intravenous dose of 100 mg kg-1 of paracetamol, no significant changes were found in the elimination rate constant (k), the mean residence time (MRT), total plasma clearance (Cl) and the apparent volume of distribution at steady-state (Vss). However, rats deprived of water for 96 h excreted a larger percentage of the administered dose as the glucuronide conjugate (15.3 vs 7.9%) and a smaller percentage as unchanged paracetamol (7.3 vs 20.7%) in the urine. In addition, there was a significant two-fold increase in the partial metabolic clearance to paracetamol glucuronide. Water deprivation also led to a significant reduction in the renal clearance of paracetamol accompanied by an increase in the renal clearance of the glucuronide.

Influence of short-term water deprivation on antipyrine disposition

The effects of acute (96 h) water deprivation on the disposition kinetics of antipyrine and hepatic cytochrome P-450 content were investigated in male rats. The disposition kinetics of antipyrine in rats deprived of water for 96 h was altered significantly: the total body clearance and steady-state volume of distribution decreased by 27.1 and 22.4%, respectively, as compared to control rats. There was no significant change in the disposition rate constant as a result of simultaneous changes in the volume of distribution and clearance. There was a 51.4% decrease in the hepatic cytochrome P-450 content in water-deprived rats. These results suggest that the pharmacokinetic changes observed in acute water deprivation with a model drug, antipyrine, are related to a decrease in total body water and to a reduced amount and/or activity of the hepatic microsomal oxidative enzymes.

Unbound plasma salicylate concentration in rheumatoid arthritis patients

This study was designed to investigate the relationship of free plasma salicylate to total plasma salicylate and to determine the clinical utility of monitoring the free plasma salicylate concentration. Analysis of 46 patient samples indicated a close correlation between the free and total plasma concentration and that there is no additional advantage to monitoring the free plasma salicylate concentration. Also this study re-emphasizes the unique pharmacokinetic characteristics of salicylate, whereby the amount of free plasma salicylate increases disproportionately with increased total plasma salicylate concentration.

A new metabolite of butylated hydroxyanisole in man

Butylated hydroxyanisole (I) is one of the most commonly used food antioxidants. Its use has been suggested to inhibit a variety of carcinogenic responses. The present study on the disposition kinetics of (I) in man indicates that contrary to previous reports, (I) undergoes significant O-demethylation in the body yielding a tert-butyl hydroquinone. It is suggested that this metabolic conversion may be responsible for some of the in vivo activities of (I) against chemical carcinogens.

Effect of water deprivation on aspirin disposition kinetics

Temporary water deprivation results in serious stress causing significant physiological, hormonal, and enzymatic changes in the body which can affect the disposition kinetics, toxicity, and activity of drugs. This study attempts to recognize the effect of water deprivation on drug disposition kinetics using aspirin. No significant effects were noted following 36-hr water deprivation in rats on the metabolism of aspirin; there was also no effect of heparinization on aspirin disposition kinetics. The disposition of salicylic acid, however, was altered significantly, with the half-life increased by approximately 72% concomitant with decreased total body clearance. The effect of two dose levels, 5 and 10 mg/kg, was also studied to elucidate nonlinearity in the disposition kinetic model. Almost complete urinary recovery of aspirin was obtained in the intact form or as metabolites. At the 10-mg/kg dose, the fraction of salicyluric acid excreted decreased significantly compared with the 5-mg/kg dose. However, the effect of water deprivation was uniform at the two dose levels without any effect on the excretion of salicyluric acid. It is suggested that, in view of the significant changes in the disposition characteristics of salicylates with water deprivation, due care must be exercised in adjusting doses giving proper consideration to body hydration levels.

High-performance liquid chromatographic determination of aspirin and its metabolites in plasma and urine

A simple quantitative method for the rapid determination of aspirin and its metabolites, salicylic acid, salicyluric acid, and gentisic acid, in plasma and urine using o-toluic and o-anisic acids, respectively, as internal standards was developed. Plasma proteins were precipitated by the addition of acetonitrile and, after centrifugation, the supernatant fluid was injected directly onto a reverse-phase column. The mobile phase consisted of an isocratic mixture of water, methanol, and glacial acetic acid (64:25:1, v/v/v) and the separated components were detected at 238 nm using a UV detector. Concentrations greater than or equal to 0.5 microgram/ml could be quantitated for aspirin or its metabolites in plasma. The peak heights and peak height ratios to the internal standard, o-toluic acid, were linear for the concentration range of 0.5-200 micrograms/ml. The aspirin metabolites in urine were isolated by extracting the acidified urine with either and then reextracting the material into an aqueous buffer solution at pH 7.0. Twenty microliters of the buffer extract was directly injected onto the column. The separated components were detected and quantitated at 305 nm. Concentrations greater than or equal to 5 micrograms/ml of salicyluric acid, salicylic acid, and gentisic acid could be determined accurately. The peak heights and peak height ratios to the internal standard, o-anisic acid, were found to be linear for the concentration range of 5-200 micrograms/ml in urine.

Simple reliable method for chronic cannulation of the jugular vein for pharmacokinetic studies in rats

A simple method for the preparation and implantation of silicone cannulas into the rat jugular vein is described. The implanted cannula can be used to administer drugs and collect blood samples at intervals of less than or equal to 1 min without causing stress to the animal. If necessary, the animals can be exsanuinated within a few minutes using this cannula. With proper maintenance, the cannula is patent for weeks and could be used for repeated and crossover studies.

Stability of aspirin in different media

Aspirin rapidly hydrolyzes in various aqueous, organic, and biological media. The purpose of this investigation was to study the decomposition of aspirin in the media that comes in contact with it during analysis in biological fluids for pharmacokinetic studies. These media included water, water-polyethylene glycol 400, water-methanol-acetic acid, phosphate buffer, freshly drawn blood and plasma from control rats and rats deprived of water for 36 hr, and blood precipitated with acetonitrile. Studies were also conducted to determine the decomposition as a function of temperature and pH. Of the various solvent systems studied, aspirin was found most stable in water-polyethylene glycol (4:1, v/v),which provides an excellent medium for preparation of intravenous dosage forms. Phosphate buffer showed significant catalysis of aspirin hydrolysis. A more than fivefold increase in the hydrolysis of aspirin was noted when the temperature was raised to 37 degrees from 22.5 degrees. The hydrolysis of aspirin in rat blood was 13 times faster than that in plasma, with an average half-life in blood of approximately 13 min. This creates significant problems in aspirin disposition kinetic studies. Mixing the blood sample immediately after collection with twice the volume of acetonitrile and thn en centrifuging gives a plasma-acetonitrile mixture in which no lysis of blood cells is observed.

Absorption and disposition characteristics of nitrofurantoin in dogs

This study reports the disposition kinetic properties of nitrofurantoin in dogs following single intravenous and oral administration of various formulations of nitrofurantoin. Also reported here is the effect of delaying gastric emptying by food and atropine on the absorption characteristics of nitrofurantoin. The drug absorption parameters calculated using a deconvolution computer program indicate that the rate and extent of enterohepatic recycling affects the elimination and absorption rate constants and thus confound the bioavailability calculations of nitrofurantoin, heretofore unrecognized in the literature. The plasma half-life following intravenous administration was 31 min (monoexponential equation) with little effect of enterohepatic recycling noted. Following oral administration, a biexponential equation with lag-time was used to fit the blood levels. The absorption half-lives were higher when nitrofurantoin was administered as a solid dosage form compared to a solution. The absorption half-lives following tablet administration ranged from 30 to 72 min and were not affected by food or atropine. The elimination half-lives following oral administration ranged from 19 to 87 min with significantly prolonged elimination when solid dosage forms were administered compared to solution. The extent of absorption ranged from 38 to 120 per cent. A direct correlation between the absorption and elimination half-life was established, indicating that increased biliary recycling direct affects the apparent disposition half-life. The three brands of nitrofurantoin tested for bioavailability showed that the use of blood levels without appropriate corrections for biliary recycling are not suitable for bioavailability testing of nitrofurantoin. The use of urinary excretion data in evaluating nitrofurantoin bioavailability is also questioned in the study.

Comparative pharmacokinetics of butylated hydroxyanisole and butylated hydroxytoluene in rabbits

The widespread use of butylated hydroxyanisole (I) and butylated hydroxytoluene (II) as food antioxidants recently has been criticized by the Food and Drug Administration because of their pharmacological and toxicological effects. Interest also has arisen recently in the use of these compounds as anticancer agents. The purposes of this study were to evaluate the pharmacokinetics of I and II in rabbits and to compare their physicochemical properties with their disposition kinetics. It was found that I has a disposition half-life of approximately 1 hr, compared to 11 days for II. These differences are explained in terms of their lipid solubility and protein binding characteristics.

Multicompartment pharmacokinetic analysis and simulations using a programmable calculator

This paper describes the use of a programmable calculator (HP-97), for fitting plasma concentration profiles to 1 and 2 compartment open models and calculating fitted and derived parameters together with estimates of steady state plasma drug levels following various dosage regimens in clinical settings.

GLC determination of butylated hydroxyanisole in human plasma and urine

A highly sensitive and specific GLC method was developed for the analysis of butylated hydroxyanisole, a commonly used antioxidant. Concentrations below 100 ng/ml could be detected in human plasma and urine. Preliminary pharmacokinetic studies demonstrated that, upon administration of 100 mg po, butylated hydroxyanisole was quickly absorbed and removed from the plasma with a high degree of intersubject variability.