Controlled Release of Molecules to Enhance Cell Survival and Regeneration.

Controlled release or controlled drug delivery comprises the set of techniques and approaches to improve bioavailability through improved safety and/or efficacy using a carrier material for the molecule of interest. The predictability and tunability of these carriers make them ideal for protection, localization, and sustained presentation of a wide range of therapeutics, including growth factors implicated in cell survival and regeneration. Here we provide a method for encapsulating epidermal growth factor in a degradable polymer matrix for delivery to the cornea. Additional notes are included to demonstrate the wide-ranging capabilities of such methods for other materials, therapeutic agents, and sites of action within the eye.

A comparative analysis of the effectiveness of laser correction with a mechanical and laser microkeratome for myopia

ABSTRACT Purpose: Myopia, or nearsightedness, is one of the most common eye conditions worldwide. However, a comparison of the effectiveness of different laser-assisted interventions is lacking. Thus, we aimed to compare the efficacy and safety of LASIK and IntraLASIK in addressing myopia. Methods: The study was conducted in two ophthalmology clinics in Beijing, China, in 2022. A total of 84 patients (152 eyes) with different degrees of myopia were examined and underwent LASIK (n=46, 80 eyes) or IntraLASIK (n=38, 72 eyes). Keratometry, corneal topography, pachymetry, visual acuity evaluation, and corneal biomechanical analysis were performed before and after the intervention. Results: IntraLASIK produced more precise flaps than LASIK, with deviations of <8 mm and 0.1 mm from the intended thickness and diameter, respectively. LASIK resulted in nonuniform flaps, with thickness deviations of 5-86 mm. IntraLASIK demonstrated a superior efficacy for patients with severe myopia and thin corneas, with a mean spherical equivalent of 0.9 D at 6 months compared to the 1.4 D for LASIK. Approximately 91% and 83% of the patients with mild to moderate and severe myopia, respectively, achieved results within ± 0.49 D from the refractive target with IntraLASIK. Conclusions: Corneal hysteresis and corneal resistance factor decreased with an increase in laser intensity, and they decreased faster with thinner corneas. Thus, IntraLASIK is more useful than LASIK in patients with thin corneas and severe myopia.

Associations of ocular anterior segment structures with sex and age: the Yamagata study (Funagata).

PURPOSE: To investigate the associations of tomographic parameters in anterior segment optical coherence tomography (AS-OCT) with sex and age in a cohort study. STUDY DESIGN: A cohort design. MATERIALS AND METHODS: AS-OCT data from 391 Japanese participants aged ≥ 35 years were obtained using swept-source OCT. In the cornea, the keratometric power at the flat (Kf) and steep (Ks) meridians, maximum keratometric power (Kmax), keratometric cylinder, spherical power, regular astigmatism, asymmetry, higher-order irregularity (HOI) from the anterior and posterior surfaces, and the central and thinnest corneal thicknesses were evaluated. Also, anterior chamber depth (ACD), lens thickness, crystalline lens rise (CLR), and nasal and temporal angle opening distances at 500 µm from the scleral spur (AOD500) were assessed. Sex differences and age-related changes were analyzed. RESULTS: Women exhibited higher anterior Kf, Ks, and Kmax and lower posterior Kf, Ks, and Kmax than men. The ACD and nasal/temporal AOD500 were shorter in women than in men. The CLR was higher in women, whereas the lens thickness did not differ between the sexes, indicating a more anteriorly positioned lens in women. Age-related changes included increased anterior/posterior HOI, increased lens thickness and CLR resulting in decreased ACD and AOD500. CONCLUSION: This study reveals sex-related differences in corneal shape, anterior chamber conformation, and lens position, as well as age-related changes in tomographic parameters. ACD, CLR, nasal and temporal AOD500 showed significant sex differences in the 50-70 s, whereas lens thickness showed no difference.

Replication kinetics and cytopathic effect of feline calicivirus in feline corneal epithelial cells.

OBJECTIVE: To determine the replication kinetics and cytopathic effect (CPE) of feline calicivirus (FCV) in feline corneal epithelial cells (FCEC). ANIMALS STUDIED: Seven archived FCV isolates and one archived feline herpesvirus type 1 (FHV-1) isolate, previously obtained from eight domestic short hair cats. PROCEDURES: FCV RNA was extracted for sequencing using Illumina MiSeq, to identify three genomically diverse isolates for further testing. Following reference-based assembly, viral genomes were annotated and assessed. Superficial keratectomies were performed to isolate the corneal epithelium of cats and the cells were cultured in vitro. FCEC were infected with the three chosen FCV isolates and one FHV-1 isolate at two different multiplicity of infection ratios (MOIs, 0.1 and 0.01 PFU/cell) and virus titration was assessed at 0, 2, 6, 12, 24, and 48 h post-infection (hpi). Viral identity was confirmed by RT-qPCR. RESULTS: Three genomically diverse FCV isolates were chosen for further assessment in the FCEC model. All infections of FCEC with FCV led to visible CPE, characterized by epithelial cell rounding and detachment from the plate by 24 hpi, while FHV-1 led to visible CPE within 48 hpi. All three of the FCV isolates replicated effectively in FCEC at both 0.1 and 0.01 MOI, with a peak increase in titer approximately 12-24 hpi. CONCLUSIONS: The results support the possible role of FCV as a primary pathogen of the feline ocular surface. FCV replicates in FCEC in vitro, leading to profound CPE.

Descemet Endothelial Thickness Comparison Trial II (DETECT II): multicentre, outcome assessor-masked, placebo-controlled trial comparing Descemet membrane endothelial keratoplasty (DMEK) to Descemet stripping only (DSO) with adjunctive ripasudil for Fuchs dystrophy.

INTRODUCTION: It remains uncertain whether Descemet membrane endothelial keratoplasty (DMEK) or Descemet stripping only (DSO) yields better outcomes in patients with symptomatic Fuchs endothelial corneal dystrophy (FECD). This paper presents the protocol for the Descemet Endothelial Thickness Comparison Trial II (DETECT II), a multicentre, outcome-masked, randomised, placebo-controlled, clinical trial comparing DMEK to DSO with ripasudil (DSO-R) for this patient population. METHODS AND ANALYSIS: A total of 60 patients with endothelial dysfunction due to symptomatic FECD will be enrolled from seven participating sites in the USA. The patients will be randomly assigned in a 1:1 ratio to one of the following treatment groups: group 1-DMEK plus topical placebo and group 2-DSO plus topical ripasudil 0.4%. The enrolment period is 24 months. The primary outcome is best spectacle-corrected visual acuity at 12 months. Secondary outcomes include peripheral and central endothelial cell density, visual acuity, vision-related quality of life and Pentacam Scheimpflug tomography. Study outcomes will be analysed using mixed effects linear regression. Adverse events, including rebubble procedures, endothelial failure and graft rejection, will be documented and analysed using appropriate statistical methods. DETECT II aims to provide evidence on the comparative effectiveness of DMEK and DSO-R. The results of this trial will contribute to optimising the treatment of FECD, while also exploring the cost-effectiveness of these interventions. Dissemination of findings through peer-reviewed publications and national/international meetings will facilitate knowledge translation and guide clinical practice in the field of corneal transplantation. ETHICS AND DISSEMINATION: A data and safety monitoring committee has been empanelled by the National Eye Institute. All study protocols will be subject to review and approval by WCG IRB as the single IRB of record. This study will comply with the National Institute of Health (NIH) Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Data from the trial will be made available on reasonable request. TRIAL REGISTRATION NUMBER: NCT05275972.

Segmentation and multiparametric evaluation of corneal whorl-like nerves for in vivo confocal microscopy images in dry eye disease.

OBJECTIVE: To establish an automated corneal nerve analysis system for corneal in vivo confocal microscopy (IVCM) images from both the whorl-like corneal nerves in the inferior whorl (IW) region and the straight ones in the central cornea and to characterise the geometric features of cornea nerves in dry eye disease (DED). METHODS AND ANALYSIS: An encoder-decoder-based semi-supervised method was proposed for corneal nerve segmentation. This model's performance was compared with the ground truth provided by experienced clinicians, using Dice similarity coefficient (DSC), mean intersection over union (mIoU), accuracy (Acc), sensitivity (Sen) and specificity (Spe). The corneal nerve total length (CNFL), tortuosity (CNTor), fractal dimension (CNDf) and number of branching points (CNBP) were used for further analysis in an independent DED dataset including 50 patients with DED and 30 healthy controls. RESULTS: The model achieved 95.72% Acc, 97.88% Spe, 80.61% Sen, 75.26% DSC, 77.57% mIoU and an area under the curve value of 0.98. For clinical evaluation, the CNFL, CNBP and CNDf for whorl-like and straight nerves showed a significant decrease in DED patients compared with healthy controls (p<0.05). Additionally, significantly elevated CNTor was detected in the IW in DED patients (p<0.05). The CNTor for straight corneal nerves, however, showed no significant alteration in DED patients (p>0.05). CONCLUSION: The proposed method segments both whorl-like and straight corneal nerves in IVCM images with high accuracy and offered parameters to objectively quantify DED-induced corneal nerve injury. The IW is an effective region to detect alterations of multiple geometric indices in DED patients.

The caretaker-reversible Tarsorrhaphy.

PURPOSE: To present a modification of the reversible tarsorrhaphy that can be opened and reclosed as necessary by caretakers and the patient. METHODS: Retrospective case series of patients who underwent the reversible tarsorrhaphy. Materials included intravenous (IV) tubing as bolsters and 4-0 polypropylene suture. The 4-0 suture is first passed through and through one end of IV tubing approximately 20 mm in length. Starting on the lateral upper lid and approximately 4 mm above the lash line, the suture is placed through the skin and into the tarsus. The suture exits through the eyelid gray line. These steps through the eyelid are repeated in the opposite direction. An air knot is tied above the upper eyelid near the base of IV tubing. A second air knot can be tied higher to provide a handle easily allowing the caretaker to close the eyelid. RESULTS: Included were 13 patients (ages 21-95-yeas), indications included lagophthalmos secondary to cicatricial changes from burns (2), keratouveitis (1), neurogenic palsy (3), neurotrophic ulcer (6), and cicatricial changes from skin cancer (1). There were no reported difficulties in maintaining the tarsorrhaphy by either family members or healthcare providers. The first tarsorrhaphy for each patient lasted between 3-19 weeks, with an average of 8 weeks. All were well tolerated. CONCLUSIONS: The caretaker-reversible tarsorrhaphy can be used as a temporizing measure. The technique balances the need for ocular protection with the need for examination/treatment by health care professionals and, equally importantly, the patients and caretakers.

Recent advances in NLRP3 inflammasome in corneal diseases: Preclinical insights and therapeutic implications.

NLRP3 inflammasome is a cytosolic multiprotein complex formed in response to exogenous environmental stress and cellular damage. The three major components of the NLRP3 inflammasome are the innate immunoreceptor protein NLRP3, the adapter protein apoptosis-associated speck-like protein containing a C-terminal caspase activation and recruitment domain, and the inflammatory protease enzyme caspase-1. The integrated NLRP3 inflammasome triggers the activation of caspase-1, leading to GSDMD-dependent pyroptosis and facilitating the maturation and release of inflammatory cytokines, namely interleukin (IL)-18 and IL-1ß. However, the inflammatory responses mediated by the NLRP3 inflammasome exhibit dual functions in innate immune defense and cellular homeostasis. Aberrant activation of the NLRP3 inflammasome matters in the etiology and pathophysiology of various corneal diseases. Corneal alkali burn can induce pyroptosis, neutrophil infiltration, and corneal angiogenesis via the activation of NLRP3 inflammasome. When various pathogens invade the cornea, NLRP3 inflammasome recognizes pathogen-associated molecular patterns or damage-associated molecular patterns to engage in pro-inflammatory and anti-inflammatory mechanisms. Moreover, chronic inflammation and proinflammatory cascades mediated by the NLRP3 inflammasome contribute to the pathogenesis of diabetic keratopathy. Furthermore, overproduction of reactive oxygen species, mitochondrial dysfunction, and toll-like receptor-mediated activation of nuclear factor kappa B drive the stimulation of NLRP3 inflammasome and participate in the progression of dry eye disease. However, there still exist controversies regarding the regulatory pathways of the NLRP3 inflammasome. In this review, we provide a comprehensive overview of recent advancements in the function of NLRP3 inflammasome in corneal diseases and its regulatory pathways primarily through studies using animal models. Furthermore, we explore prospects for pharmacologically targeting pathways associated with NLRP3.

A unique and biocompatible corneal collagen crosslinking in vivo.

Corneal crosslinking (CXL) is a widely applied technique to halt the progression of ectatic diseases through increasing the thickness and mechanical stiffness of the cornea. This study investigated the biocompatibility and efficiency of a novel CXL procedure using ruthenium and blue light in rat corneas and evaluated parameters important for clinical application. To perform the CXL procedure, the corneal epithelium of rats was removed under anaesthesia, followed by the application of a solution containing ruthenium and sodium persulfate (SPS). The corneas were then exposed to blue light at 430 nm at 3 mW/cm2 for 5 min. Rat corneas were examined and evaluated for corneal opacity, corneal and limbal neovascularization, and corneal epithelial regeneration on days 0, 1, 3, 6, 8, and 14. On day 28, the corneas were isolated for subsequent tissue follow-up and analysis. CXL with ruthenium and blue light showed rapid epithelial healing, with 100% regeneration of the corneal epithelium and no corneal opacity on day 6. The ruthenium group also exhibited significantly reduced corneal (p < 0.01) and limbal neovascularization (p < 0.001). Histological analysis revealed no signs of cellular damage or apoptosis, which further confirms the biocompatibility and nontoxicity of our method. Confocal and scanning electron microscopy (SEM) images confirmed high density of collagen fibrils, indicating efficient crosslinking and enhanced structural integrity. This study is unique that demonstrates in vivo safety, biocompatibility, and functionality of ruthenium and blue light CXL. This approach can prevent toxicity caused by UV-A light and can be an immediate alternative compared to the existing crosslinking procedures that have side effects and clinical risks for the patients.

Treatment of equine keratomycosis, part 1: selection of appropriate therapy based on clinical presentation and diagnostic testing improves clinical outcomes.

OBJECTIVE: To determine clinical outcome, treatment costs, and hospitalization duration in horses treated for keratomycosis and identify ophthalmic examination and diagnostic results associated with these outcomes. METHODS: This was a retrospective study of 126 equine keratomycosis cases between 2004 and 2020 with fungal infection confirmed on cytology, culture, and/or histopathology and a minimum of 1-month follow-up. Details of the ophthalmic examination, diagnostic test results, and treatment and cost outcomes were recorded. Outcomes of interest were analyzed by treatment type. The relationship of patient and diagnostic test variables to the outcomes of interest was determined via logistic and linear regression models. RESULTS: Globe retention and positive visual outcome occurred in 82.5% and 78.9% of medically and 88.4% and 85.5% of surgically treated cases, respectively. While not statistically significant, there were more positive clinical outcomes with surgery; in recent years, the globe and vision were preserved in 94.7% of cases following penetrating keratoplasty. The choice to pursue surgery was related to lesion depth. Medical treatment was associated with statistically shorter hospitalization times and lower total and hospitalization invoices compared to all surgical treatments. Diagnosis of stromal abscess was associated with higher total invoice and longer hospitalization times compared to ulcerative keratomycosis, although clinical outcomes were similar. CONCLUSIONS: Overall positive clinical outcomes were achieved despite the severity of the disease in many cases, highlighting the need for appropriate treatment selection based on clinical presentation. CLINICAL RELEVANCE: Expanding knowledge of clinical decision-making, treatment options, and associated clinical and financial outcomes may further improve outcomes for equine keratomycosis patients.

Innervation in corneal bioengineering.

Given the crucial role nerves play in maintaining corneal function and integrity, the ability of bioengineered cornea to demonstrate functional nerve regeneration directly influences their longevity and stability. Despite advances in biofabrication techniques and an increasing appreciation of the importance of neural innervation, to this day none have completely replicated the complexity and functionality of the cornea with successful innervation. This review evaluates the materials and fabrication techniques used to produce and enhance innervation in bioengineered cornea. Approaches to facilitating innervation are discussed and methods of assessing innervation compared. Finally, current challenges and future directions for innervated bioengineered cornea are presented, providing guidance for future work. STATEMENT OF SIGNIFICANCE: The functional nerve regeneration in bioengineered corneas directly influences their longevity and stability. Despite advancements in biofabrication techniques and growing recognition of the importance of neural innervation for bioengineered cornea, there remains a lack of comprehensive reviews on this topic. This review addresses the critical gap by evaluating the materials and fabrication techniques employed to promote innervation in bioengineered corneas. Additionally, we discuss various approaches to enhancing innervation, compare assessment methods, and examine both in vitro and in vivo responses. By providing a comprehensive overview of the current state of research and highlighting challenges and future directions, this review aims to provide guidance for inducing innervation of bioengineered cornea.

Epidemiological Study and Seropositivity in Viral Panel Testing Among Corneal Tissue Donors.

BACKGROUND: Corneal tissue is a critical component for vision restoration through transplantation, yet the availability of suitable corneal tissue is limited. This limitation results in long waiting lists and high demand, especially in countries with lower donation rates compared to global benchmarks. In Mexico, the corneal donation rate remains significantly behind other Latin American countries and leading nations such as Spain. Understanding the characteristics of corneal tissue donors is essential for improving donation practices and addressing the shortage of available tissues. MATERIALS AND METHODS: This descriptive retrospective study analyzed electronic medical records of cadaveric corneal donors at the General Regional Hospital 1 of the Mexican Social Security Institute of Querétaro from January 2022 to December 2023. Donors were included based on criteria such as age (2-85 years) and known cause of death. Exclusion criteria included age outside the specified range, neoplastic diseases, active systemic infections, and prior ocular surgeries. Serological testing for human immunodeficiency virus (HIV), Venereal Disease Research Laboratory (VDRL), coronavirus disease 2019 (COVID-19), hepatitis B virus (HBV), and hepatitis C virus (HCV was performed to assess viral reactivity. Statistical analyses were conducted using IBM SPSS Statistics for Windows, Version 25 (Released 2017; IBM Corp., Armonk, New York, United States), summarizing data with descriptive statistics. RESULTS: The study included 185 corneal donors with a mean age of 56.34 years. The majority were male (109; 58.9%), and the leading causes of death were cardiogenic shock (34; 18.4%), hypovolemic shock (31; 16.8%), and acute respiratory failure (30; 16.2%). Exclusion due to positive serological tests included seven donors (3.8%) for HIV and seven (3.8%) for SARS-CoV-2. A total of 16 donors (8.6%) were excluded due to positive results in the viral serological panel. The most common comorbidities were chronic kidney disease (36; 19.5%), type 2 diabetes mellitus (28; 15.1%), and systemic hypertension (31; 16.8%). CONCLUSIONS: The study highlights a predominantly male donor profile with a mean age of 56.34 years and emphasizes cardiogenic shock as a leading cause of death. The notably higher seropositivity rate of 8.6% for various viral infections compared to international reports indicates a need for improved health interventions and screening processes. The focus on cardiovascular and respiratory causes of death underscores regional health issues affecting donation patterns. To address the organ and tissue donation shortfall, it is crucial to enhance coordination within donation teams and increase public awareness, given the significant gap in donation rates compared to leading countries.

Fungal Keratitis in Northwestern Spain: Epidemiology, Risk Factors and Outcomes.

PURPOSE: To review the clinical features, risk factors, microbiological profile, and treatment regimens of fungal keratitis in Galicia, a region in Northwestern Spain with temperate humid weather. PATIENTS AND METHODS: A retrospective case series was employed, including patients with fungal keratitis from nine hospitals within the region of Galicia, Spain, between 2010 and 2020. Data obtained from clinical records were analysed. RESULTS: Out of 654 cases of infectious keratitis, 77 cases (9.9%) were identified as fungal keratitis. The median age of affected patients was 68.0 years, with a higher incidence in rural areas (62.3%). Candida spp. infections were the most frequent type (55.8%) and were associated with a higher median age than were the non-dermatophyte mould infections. The primary risk factors included steroid eyedrop use (29.9%), recent keratoplasty (18.2%), ocular trauma (19.5%), and contact with vegetable matter (11.7%). Most ulcers displayed stromal involvement, and 37.7% presented corneal thinning. The median duration of infection was longer in fungal than in bacterial keratitis, and surgical intervention was required in 48.1% of cases. CONCLUSIONS: Fungal keratitis, mainly involving Candida spp., accounted for 9.9% of microbial keratitis cases in Galicia, Spain, with significant risk factors being topical steroid use, ocular trauma, and contact with vegetable matter. Delayed diagnosis often resulted in poor outcomes, highlighting the need for early detection through awareness and new technologies to improve prognosis.

[Bacterial keratitis: Retrospective and prospective 2024]. / Kératites bactériennes : rétrospective et prospective 2024.

Bacterial keratitis (BK) is an infection of the cornea caused by one or more bacteria. Contact lens wear is the main risk factor. Staphylococcus and Pseudomonas are the most frequently isolated pathogens in developed countries. BK requires a standardized work-up to avoid diagnostic and therapeutic delays that may negatively affect visual prognosis. Corneal signs, the speed at which lesions progress and the presence of risk factors allow the clinician to presume an empirical microbiological diagnosis, but corneal scraping, which allows the isolation and identification of the bacteria involved in the infection, is the only way to confirm the diagnosis. The type of antibiotic treatment depends on the severity of the lesions, the risk factors involved, and the bacteria identified. Corticosteroids have been shown to be effective as adjuvant therapy and may be used under certain well-defined circumstances. Surgical treatment is sometimes necessary.

Keratoplasty: are children missing out on the lamellar revolution-the 2023 Bowman Club, David L. Easty Lecture.

There has been a growing interest in lamellar keratoplasty over penetrating keratoplasty in the treatment of cornea diseases. Children, in particular, may benefit from lamellar keratoplasty due to faster visual recovery, better outcomes, fewer eye drops and earlier amblyopia treatment. This review aims to examine the trends, surgical techniques and outcomes in paediatric lamellar keratoplasty. Additionally, alternative treatment modalities to keratoplasty such as selective endothelium removal in Peters anomaly and ophthalmic non-steroidal anti-inflammatory drugs eyedrops in congenital hereditary endothelial dystrophy are also discussed.

Anterior Segment Optical Coherence Tomography Angiography: A Review of Applications for the Cornea and Ocular Surface.

Dye-based angiography is the main imaging modality in evaluating the vasculature of the eye. Although most commonly used to assess retinal vasculature, it can also delineate normal and abnormal blood vessels in the anterior segment diseases-but is limited due to its invasive, time-consuming methods. Thus, anterior segment optical coherence tomography angiography (AS-OCTA) is a useful non-invasive modality capable of producing high-resolution images to evaluate the cornea and ocular surface vasculature. AS-OCTA has demonstrated the potential to detect and delineate blood vessels in the anterior segment with quality images comparable to dye-based angiography. AS-OCTA has a diverse range of applications for the cornea and ocular surface, such as objective assessment of corneal neovascularization and response to various treatments; diagnosis and evaluation of ocular surface squamous neoplasia; and evaluation of ocular surface disease including limbal stem cell deficiency and ischemia. Our review aims to summarize the new developments and clinical applications of AS-OCTA for the cornea and ocular surface.

Influence of surgeon learning on outcomes in new ophthalmic procedures: quantified nationwide evidence in endothelial corneal transplantation.

AIMS: To investigate the impact of surgeon learning on endothelial keratoplasty (EK) procedure outcomes. METHODS: A prospective nationwide registry study of EK grafts in patients aged at least 21 years with Fuchs endothelial corneal dystrophy or pseudophakic bullous keratopathy undergoing a first EK procedure in that eye between 2005 and 2020. EK procedures were either Descemet Stripping Endothelial Keratoplasty (DSEK) or Descemet Membrane Endothelial Keratoplasty (DMEK). Primary outcome was transplant survival at 2 years. Secondary outcomes at 1-year post-transplant were (1) best-corrected visual acuity, (2) requirement for repeat air injection procedures to treat graft detachment and (3) iatrogenic primary graft failure. RESULTS: Following analysis of 11 516 EK transplants, significant impact of surgeon learning was indicated by (1) the influence of surgeon prior experience in that EK technique, (2) the influence of surgeon prior experience in postoperative management and (3) the time interval from introduction of that EK technique in the United Kingdom to time of surgery. EK grafts reported to have failed within the first 6 months were a significant proportion of all transplant failures. CONCLUSIONS: Influence of surgeon learning and inexperience in EK of clinical and statistical significance can be quantified and diminishes over time. Equivalent analyses may be feasible for novel procedures in other ophthalmology specialties and surgical training. Training programmes and nationwide advisory networks may be helpful in reducing the duration and impact of surgeon learning curves.

Assessment of corneal epithelial thickness mapping by spectral-domain optical coherence tomography.

Background: To assess corneal epithelial-thickness (ET) mapping resulting from spectral-domain-optical-coherence-tomography (SD-OCT) by analysing its repeatability and reproducibility and its utility for screening corneal-refractive-surgery (CRS) candidates. Methods: ET was measured in 25-sectors by two-operators. Intra-subject-standard-deviation, coefficient-of-repeatability (CoR) and coefficient-of-variability (CoV) were calculated to evaluate repeatability. Reproducibility was evaluated using a Bland-Altman analysis. Scheimpflug-tomography, refraction, visual acuity, and patient history were used to make a decision on eligibility for CRS. After this decision, the surgeon was shown the patient's ET map and was asked to reconsider his analysis. The percentage of screenings that changed after evaluating the ET maps was determined. Results: Forty-three eyes with normal corneas (CRS-group) and 21 eyes not suitable for CRS (non-CRS-group) were studied. For the CRS-group, CoR ranged from 2.03 (central) to 19.73 µm (outer-inferonasal), with the central-sector showing the highest repeatability (CoV: 1.53-1.80%). For the non-CRS-group, CoR ranged from 3.82 (central-middle-superonasal) to 13.42 µm (middle-inferotemporal), with the inner-superonasal-sector showing the highest repeatability (CoV: 2.86-4.46%). There was no statistically significant difference between operators (p > 0.01). In the CRS-group, the outcomes showed a narrow 95% limits-of-agreement (LoA) for the central-and inner-nasal-sectors (about 4 µm), and wider for the inner-superior, outer-superotemporal and outer-inferonasal (about 10-14 µm). In the non-CRS-group, they were for the outer superonasal (about 4 µm), and for the middle-inferotemporal and outer-temporal (about 10 µm), respectively. Candidacy for CRS changed in 7.82% of patients after evaluation of the ET maps, with all of them screened-out. Conclusion: The SD-OCT provided repeatable and reproducible corneal ET measurements and may alter candidacy for CRS. Clinical trial registration: German Clinical Trials Register: https://drks.de/search/en/trial/DRKS00032797, identifier: DRKS00032797.

Analysis of factors influencing refractive error in Fuchs eyes undergoing Descemet membrane endothelial keratoplasty triple procedure.

PURPOSE: To evaluate the accuracy of current intraocular lens (IOL) formulas and identify factors influencing mean error in eyes undergoing Descemet membrane endothelial keratoplasty (DMEK) triple procedure, that is, DMEK combined with cataract extraction and IOL placement for concurrent Fuchs endothelial corneal dystrophy (FECD) and cataracts. DESIGN: Retrospective cohort study. SUBJECTS: 90 eyes with FECD undergoing uncomplicated DMEK triple procedure at Wilmer Eye Institute. METHODS: We analysed tomographic features of oedema, including loss of regular isopachs, displacement of the thinnest point of the cornea and the presence of posterior surface depression, and assessed the correlation with the prediction error. MAIN OUTCOME MEASURES: We compared the mean error (±SD) for the Barrett Universal II (BU2), Hoffer QST, Haigis-L (HL) and Barrett True K (BTK) formulas and the percentage of eyes within 0.25, 0.5 and 1 diopter (D) of error. RESULTS: All formulas resulted in a mean hyperopic error, with the HL having the lowest mean error of 0.24 D (±0.97 D) and BU2 having the highest ME of 0.94 D (±0.97 D). For each additional tomographic feature of corneal oedema in the BU2 and Hoffer QST formulas, the mean hyperopic error increased by 0.38 D. For the BTK and HL formulas, the mean error increased by 0.35 D (p<0.001). CONCLUSION: The number of tomographic features of oedema can be useful in identifying eyes with higher errors in IOL calculation when performing the DMEK triple procedure for FECD.