Outcomes after reversed corneal graft rejection: a report from the European VISICORT project.

OBJECTIVE: This study aims to describe the outcome of corneal grafts, both low risk and high risk, after successfully reversed immunological rejection. METHODS: Datasets on reversed rejection episodes in penetrating and endothelial keratoplasties between 2014 and 2019 (n=876) were extracted from the Adverse Immune Signatures and their Prevention in Corneal Transplantation database, which contains the prospectively and consecutively collected corneal transplants from five European centres. Stratified by the preoperatively determined risk status for immunological rejection, the outcome parameters analysed included visual acuity, intraocular pressure, endothelial cell density and central corneal thickness before and after reversed rejection episodes. RESULTS: Fourty-seven (52%) out of a total of 91 identified rejection episodes were successfully reversed and were available for analysis (23 penetrating and 24 endothelial keratoplasties). No statistically significant change was found for any of the parameters studied between the values before and the values 3 months after the rejection episode, irrespective of the preoperative risk status. CONCLUSION: The outcome of corneal grafts that survive immunological rejection may be clinically indistinguishable from the state before immunological rejection, irrespective of graft type and risk status. These findings support clinicians by providing information on prognosis after reversed rejection episodes and by giving patients realistic expectations regarding the outcome.

Clinical Evaluation of a New Spectral-Domain Optical Coherence Tomography-Based Biometer.

The VEMoS-AXL system is a new optical biometer based on spectral domain optical coherence tomography (SD-OCT) that has been tested in terms of intrasession repeatability and compared with a swept-source optical coherence tomography biometer (SS-OCT), which is recognized as the gold standard for the performance of an agreement analysis. A biometric analysis was performed three consecutive times in 120 healthy eyes of 120 patients aged between 18 and 40 years with the SD-OCT system, and afterwards, a single measurement was obtained with the SS-OCT system. Within-subject standard deviations were 0.004 mm, 4.394 µm, and 0.017 mm for axial length (AL), central corneal thickness (CCT), and anterior chamber depth (ACD) measures obtained with the SD-OCT biometer, respectively. The agreement between devices was good for AL (limits of agreement, LoA: -0.04 to 0.03 mm) and CCT (LoA: -4.36 to 14.38 µm), whereas differences between devices were clinically relevant for ACD (LoA: 0.03 to 0.21 mm). In conclusion, the VEMoS-AXL system provides consistent measures of anatomical parameters, being most of them interchangeable with those provided by the SS-OCT-based gold standard.

Intraocular pressure-related side-effects after endothelial keratoplasty.

PURPOSE: To investigate circumpapillary retinal nerve fibre layer (RNFL) thickness, pupillary function and diameter after phacoemulsification and lens implantation alone or combined with endothelial keratoplasty (EK). METHODS: This study was a secondary analysis of data from a randomized, single-masked trial, that included 72 patients with Fuchs' endothelial dystrophy and cataract, equally allocated (1:1) to ultrathin Descemet's stripping automated endothelial keratoplasty or Descemet's membrane endothelial keratoplasty. The cataract extraction (CE) group included 40 patients undergoing cataract surgery only. All patients were treated with phacoemulsification and lens implantation. RESULTS: RNFL thickness was significantly lower in the CE group than after EK for the global (p < 0.01), nasal (p = 0.04), and temporal sectors (p = 0.01) 12 months after surgery. RNFL thickness was comparable between patients treated with rebubbling and others (p ≥ 0.16 for all comparisons) after 12 months. The CE group and patients treated with EK demonstrated a comparable scotopic (p = 0.34) and photopic pupil diameter (p = 0.95) as well as a comparable maximum (p = 0.83) and average pupillary constriction velocity (p = 0.95) after 12 months. In contrast, patients treated with rebubbling had a significantly smaller scotopic pupil diameter (p = 0.04). CONCLUSION: In this study, no evidence was found indicating a negative impact on the RNFL thickness after EK when compared to CE 12 months after surgery. Iris function and pupil diameter were comparable between the CE group and patients treated with EK after 12 months.

Does Corneal Topography Using 3-Dimensional Optical Coherence Tomography Suggest Different Subtypes of Terrien Marginal Degeneration?

PURPOSE: The aim of this study was to analyze corneal topography relative to astigmatism, higher order aberrations, and corneal curvatures in Terrien marginal degeneration using 3-dimensional anterior-segment optical coherence tomography. METHODS: Twenty-nine eyes of 15 Finnish patients from a tertiary referral center had topographic axial power maps classified into 4 patterns by visual grading: crab claw (CC), mixed (M), arcuate (A), and normal. Regular astigmatism, keratometry, higher order aberrations, maximal corneal thinning, apex thickness, and curvature changes relative to best fit sphere toward maximal peripheral thinning were compared. RESULTS: Four, 9, and 12 eyes were classified as CC, M, and A, respectively; 1 as normal with clinical disease; and 3 as normal with unilateral disease. Median follow-up was 2.3 (range, 0-7.2) years. Three eyes changed pattern. Patients with the CC pattern were the youngest when diagnosed, progressed more rapidly, exhibited cavities in superior quadrants with anterior bulging, and had greater higher order posterior aberrations. Patients with the M pattern were older, progressed slower, and showed superonasal asymmetric corneal steepening extending centrally, often with asymmetric bow tie. Patients with pattern A showed little progression and were the oldest when diagnosed, with maximal corneal thinning equally in all quadrants. According to the Wang classification, the median stage was 4, 2, and 2 in CC, M, and A patterns, respectively, whereas it was always 2 by the Süveges classification. CONCLUSIONS: Terrien marginal degeneration is characterized by distinct corneal topographic patterns that differ in tomographic features, suggesting existence of subtypes in addition to different stages of disease. Patients representing CC and M patterns might benefit from more frequent monitoring.

Prospective Observational Study Evaluating Systemic Hormones and Corneal Crosslinking Effects in Keratoconus.

Purpose: To evaluate associations between hormone levels and corneal parameters in patients with keratoconus (KC), before and after photooxidative corneal collagen crosslinking (CXL). Design: Prospective, observational cohort study. Participants: Twenty-eight patients with KC who were scheduled for CXL at Aarhus University Hospital in Denmark. Methods: Androgen (dehydroepiandrosterone sulfate [DHEA-S]) and estrogen (estrone and estriol) plasma levels were measured and clinical assessments were performed before CXL and 2 to 3 months post-CXL, comparing the CXL eye with the control eye from the same participant. Main Outcome Measures: Associations between hormone levels and maximum corneal curvature (Kmax) and minimum central corneal thickness (CCtmin) before and after CXL. Results: Corneal collagen crosslinking was associated with a 2% reduction in Kmax values in the CXL eye, post-CXL, from baseline (median, 56.8 diopters [D]; 95% confidence interval [CI], 50.4-60.3) to the second visit (55.7 D; 95% CI, 50.4-58.8; P < 0.001). Systemic DHEA-S levels were 5 to 6 orders of magnitude higher than estriol or estrone concentrations in plasma. Importantly, estriol levels, rather than DHEA-S or estrone levels, were more closely correlated with Kmax before CXL (Spearman's r = 0.55, P = 0.01). Post-CXL Kmax and CCtmin were not associated with DHEA-S, estrone, or estriol plasma levels at the same timepoint. Conclusions: This study provides supporting evidence based on a KC clinical population that systemic estrogen levels may influence corneal parameters (curvature and thickness) pre-CXL. Further studies evaluating the interplay between the therapeutic benefits of CXL and systemic hormone distributions are needed to determine if perturbation of the local corneal microenvironment influences endocrine function. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.

Corneal grafting.

Corneal grafting is performed approximately 650 times a year in Denmark. A summary of these procedures is given in this review. Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy are frequent indications for transplantation. Previously, penetrating keratoplasty was the technique of choice but is nowadays mainly used for combined stromal and endothelial pathology. Instead, techniques specifically replacing diseased layers are more common. The Danish Cornea Bank is the only center in Denmark which undertakes preparation and distribution of tissue. The operative procedures are performed at Aarhus University Hospital or Rigshospitalet Glostrup.

Impact of Small Incision Lenticule Extraction for High Myopia on Intraocular Pressure Measurements With Pneumotonometry.

PURPOSE: To evaluate the medium-term impact of small incision lenticule extraction (SMILE) on air-puff tonometry (APT) and how it may be corrected. METHODS: In this controlled prospective study, 69 eyes from 69 patients treated with SMILE for high myopia (mean: -7.22 diopters) were included. Central corneal thickness (CCT), spherical equivalent refraction (SEQ), corneal power, and intraocular pressure (IOP) (assessed by APT) were measured before and 3 months after surgery. RESULTS: The measured IOP decreased significantly after SMILE surgery (mean: -6.43 mm Hg), indicating a significant underestimation of the true IOP by APT. There was a significant correlation between change in SEQ, CCT, and apparent IOP. Correcting the apparent IOP measurement by applying a multiple regression correction did not provide significantly better estimates compared to adding 6.4 mm Hg to the measurement. CONCLUSIONS: This study showed that previous SMILE surgery should be considered when interpreting APT measurements, because the measurements underestimate the true IOP. Multiple regressions cannot estimate the true IOP with certainty. For screening purposes, adding 6.4 mm Hg to the apparent IOP of a patient treated for high myopia may be sufficient. [J Refract Surg. 2023;39(9):606-611.].

Early findings in a prospective randomised study on three cross-linking treatment protocols: interruption of the iontophoresis treatment protocol.

PURPOSE: To present the outcome of the interrupted iontophoresis-assisted treatment arm in an ongoing randomised clinical trial (NCT04427956). METHODS: A randomised clinical study of corneal cross-linking (CXL) using continuous UV-A irradiation at a rate of 9 mW/cm2 and three different types of riboflavin and riboflavin delivery mode: (1) iso-osmolar dextran-based riboflavin (epithelium-off), (2) hypo-osmolar dextran-free riboflavin (epithelium-off) and (3) iontophoresis-assisted delivery of riboflavin (epithelium-on) for the treatment of progressive keratoconus. Inclusion criteria were an increase in the maximum keratometry value (Kmax) of 1.0 dioptre over 12 months or 0.5 dioptre over 6 months. The primary outcome in evaluating treatment efficacy was Kmax. Recently presented stratified detection limits were used post hoc to confirm the enrolment of patients with truly progressive keratoconus and in the assessment of the need for re-CXL. RESULTS: Thirteen patients had been randomised to iontophoresis-assisted CXL when the treatment arm was interrupted; two patients dropped out. Of the remaining 11 patients, 7 were deemed as having truly progressive disease according to the more recent stratified detection limits. The disease continued to progress in three patients according to the original definition (increase in Kmax≥1 D), necessitating re-CXL with epithelium-off CXL. This progression was confirmed by post hoc analysis using the stratified detection limits for progression. CONCLUSIONS: The iontophoresis-assisted CXL protocol failed to halt further disease progression in 27% of the patients. The failure rate increased to 38% when considering only the patients deemed to have truly progressive disease using the stratified detection limits.

Blepharitis.

Blepharitis is a chronic condition and full recovery is difficult to achieve. It requires good patient compliance and an individual treatment regime. There are many conditions which can cause blepharitis, and it is essential to find the cause to give the proper treatment. There is scarce evidence for the recommended guidelines. Blepharitis itself rarely causes vision loss, but in case of complications like keratitis it is more frequently observed. When patients do not respond to the treatment it is important to consider if it is caused by immunological diseases or carcinoma, as argued in this review.

Visual function after ultrathin Descemet's stripping automated endothelial keratoplasty or Descemet's membrane endothelial keratoplasty combined with cataract surgery: a randomised controlled clinical trial.

AIMS: To compare best-corrected visual acuity (BCVA), contrast sensitivity and endothelial cell density (ECD) after ultrathin Descemet's stripping automated endothelial keratoplasty (UT-DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK). METHODS: A randomised, single-blinded, single-centre design was used. 72 patients with Fuchs' endothelial dystrophy and cataract were randomised to UT-DSAEK or DMEK combined with phacoemulsification and lens implantation. 27 patients with cataract were included in a control group and treated with phacoemulsification and lens implantation. The primary outcome was BCVA at 12 months. RESULTS: Compared with UT-DSAEK, DMEK resulted in better BCVA with mean differences of 6.1 early treatment diabetic retinopathy study (ETDRS) (p=0.001) after 3 months, 7.4 ETDRS (p<0.001) after 6 months and 5.7 ETDRS (p<0.001) after 12 months. The control group obtained significantly better BCVA with a mean difference of 5.2 ETDRS (p<0.001) compared with DMEK 12 months postoperatively. Compared with UT-DSAEK, contrast sensitivity was significantly better 3 months after DMEK with a mean difference of 0.10 LogCS (p=0.03). However, our study found no effect after 12 months (p=0.08). ECD was significantly lower after UT-DSAEK compared with DMEK with mean differences of 332 cells/mm2 (p<0.01) after 3 months, 296 cells/mm2 (p<0.01) after 6 months and 227 cells/mm2 (p=0.03) after 12 months. CONCLUSIONS: Compared with UT-DSAEK, DMEK resulted in better BCVA 3, 6 and 12 months postoperatively. Twelve months postoperatively, DMEK had a higher ECD than UT-DSAEK; however, no difference in contrast sensitivity was found. TRIAL REGISTRATION NUMBER: NCT04417959.

Patient experience and repeatability of measurements made with the Pentacam HR in patients with keratoconus.

BACKGROUND: To investigate whether the repeatability of measurements with the Pentacam HR in patients with keratoconus is improved by patients gaining more experience of the measurement situation. Such an improvement could enhance the accuracy with which progressive keratoconus can be detected. METHODS: Four replicate measurements were performed on Day 0 and on Day 3. Parameters commonly used in the diagnosis of progressive keratoconus were included in the analysis, namely the flattest central keratometry value (K1), the steepest central keratometry value (K2), the maximum keratometry value (Kmax), and the parameters A, B and C from the Belin ABCD Progression Display. In addition, quality parameters used by the Pentacam HR to assess the quality of the measurements were included, namely the analysed area (front + back), 3D (front + back), XY, Z, and eye movements. RESULTS: Neither the diagnostic parameters nor the quality parameters showed any statistically significant improvement on Day 3 compared to Day 0. The quality parameter "eye movements" deteriorated significantly with increasing Kmax. CONCLUSION: Gaining experience of the measurement situation did not increase the accuracy of the measurements. Further investigations should be performed to determine whether the increasing number of eye movements with increasing disease severity has a negative effect on the repeatability of the measurements.

The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls.

The healthy cornea is transparent, however, disease can affect its structure, rendering it more or less opaque. The ability to assess the clarity of the cornea objectively could thus be of considerable interest for keratoconus patients. It has previously been suggested that densitometry can be used to diagnose early keratoconus, and that the values of densitometry variables increase with increasing disease severity, indicating that densitometry could also be used to assess progressive keratoconus. Previous studies have only assessed the repeatability of corneal densitometry measurements on the same day, which does not reflect the clinical setting in which changes are evaluated over time. We have therefore evaluated the inter-day repeatability of densitometry measurements in both patients with keratoconus and healthy controls. Measurements in the middle layer of the 2-6 mm zone of the cornea showed the best repeatability. Although an objective measure of the corneal transparency could be interesting, the generally poor repeatability of densitometry measurements limits their use. The repeatability of corneal clarity measurements could be improved by using other approaches such as optical coherence tomography, but this remains to be investigated. Such improvements would allow the more widespread use of corneal densitometry in clinical practice.

Macular Thickness After Ultrathin Descemet Stripping Automated Endothelial Keratoplasty and Descemet Membrane Endothelial Keratoplasty Combined With Cataract Surgery: A Randomized Controlled Clinical Trial.

PURPOSE: The aim was to investigate alterations in central retinal thickness (CRT) and their implications for visual acuity after ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) combined with cataract surgery. METHODS: A total of 72 eyes of 72 patients with Fuchs endothelial dystrophy and cataract were included and equally randomized to either UT-DSAEK or DMEK. A control group of 40 eyes of 40 patients with cataract were included for cataract surgery. All participants were examined preoperatively as well as 3 and 6 months postoperatively. RESULTS: There was no significant difference in CRT between the study groups after surgery ( P = 0.896). A significant difference in best-corrected visual acuity (BCVA) progression over time was found between the study groups ( P < 0.0001). Average improvements of 8.03 EDTRS after UT-DSAEK ( P < 0.001) and 16.77 EDTRS after DMEK ( P < 0.001) were found 6 months postoperatively. No significant correlation was found between the change in BCVA and CRT from baseline to 3 months postoperatively (r 2 < 0.0001, P = 0.96) and from baseline to 6 months postoperatively (r 2 = 0.0053, P = 0.46). CONCLUSIONS: CRT was not altered by UT-DSAEK, DMEK, or cataract surgery 3 and 6 months postoperatively. BCVA significantly improved 3 and 6 months after UT-DSAEK and DMEK, respectively. No significant correlations were found between the change in BCVA and CRT postoperatively. As such CRT alterations were comparable after UT-DSAEK, DMEK, and cataract surgery.

Low-Dose Atropine Induces Changes in Ocular Biometrics in Myopic Children: Exploring Temporal Changes by Linear Mixed Models and Contribution to Treatment Effect by Mediation Analyses.

This study aimed to investigate changes in non-cycloplegic ocular biometrics during the initial six months of treatment with a 0.1% atropine loading dose and 0.01% atropine compared with a placebo and analyze their contribution to the treatment effect on cycloplegic spherical equivalent (SE) progression. The study was based on a randomized, double-masked, placebo-controlled, multicenter trial evaluating a 0.1% atropine six-month loading dose and 0.01% atropine in reducing myopic progression in Danish children. The treatment phase was 24 months, and the washout phase was 12 months. Parameters measured included changes in axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and choroidal thickness (ChT), while cycloplegic SE and lens power were calculated. Longitudinal changes and contributions to treatment effects were analyzed using constrained linear mixed models and mediation analyses, respectively. After six months, AL was 0.13 mm shorter (95% confidence interval [CI], -0.18 to -0.07 [adjusted p < 0.001]) and 0.06 mm shorter (95% CI, -0.11 to -0.01 [adjusted p = 0.060]) with a 0.1% atropine loading dose and 0.01% atropine, respectively, compared to the placebo group. Similar concentration-dependent changes were found with ACD, LT, VCD, ChT, and cycloplegic SE. Although the treatment effects trended toward concentration-dependent responses, only the treatment effect mediated by AL at three months differed significantly between 0.01% atropine and a 0.1% atropine loading dose (adjusted p = 0.023). Several ocular biometrics, including AL, ACD, and LT, changed dose-dependently during low-dose atropine treatment. Moreover, the treatment effect of atropine on SE progression was mediated by a subset of ocular biometrics, mainly AL, with trends toward concentration dependency and distributional shifts over time.

Reproducibility of Mesopic and Photopic Pupil Sizes in Myopic Children Using a Dedicated Pupillometer with Human-Assisted or Automated Reading.

This study aimed to investigate the reproducibility of pupil size measurements over time and between reading methods when comparing human-assisted reading to automated reading. Pupillary data were analyzed on a subset of myopic children enrolled in a multicenter randomized clinical trial on myopia control with low-dose atropine. Pupil size measurements were obtained prior to randomization at two time points (screening and baseline visits) using a dedicated pupillometer under mesopic and photopic conditions. A customized algorithm was built to perform automated readings, allowing comparisons between human-assisted and automated readings. Reproducibility analyses followed the principles of Bland and Altman and included the calculation of the mean difference between measurements and limits of agreement (LOA). We included 43 children. Mean (standard deviation) age was 9.8 (1.7) years and 25 (58%) children were girls. Using human-assisted readings, reproducibility over time showed mesopic mean difference of 0.02 mm with LOA from -0.87 mm to 0.91 mm, whereas photopic mean difference was -0.01 mm with LOA from -0.25 mm to 0.23 mm. Reproducibility between human-assisted and automated readings was also higher under photopic conditions, with mean difference of 0.03 mm and LOA from -0.03 mm to 0.10 mm at screening and mean difference of 0.03 mm and LOA from -0.06 mm to 0.12 mm at baseline. Using a dedicated pupillometer, we found that examinations performed under photopic conditions demonstrated higher reproducibility over time and between reading methods. We speculate whether mesopic measurements are sufficiently reproducible to be monitored over time. Furthermore, photopic measurements may be of greater relevance when evaluating the side effects of atropine treatment, such as photophobia.

Ocular morbidity in Marfan syndrome: a nationwide epidemiological study.

BACKGROUND: Ophthalmic complications are profound in Marfan syndrome (MFS). However, the overall burden is not well described. Our purpose was to evaluate the ocular morbidity in a nationwide perspective. METHODS: We identified the ocular morbidity in patients with MFS (n=407) by use of Danish national healthcare registers, using number and timing of hospital contacts related to ophthalmic diagnoses, to ophthalmic surgery and to prescriptions for ophthalmic medication. An age-matched and gender-matched background population (n=40 700) was used as comparator. RESULTS: Among MFS, 56% (226/407) of the patients had at least one registration of an ophthalmic diagnosis as inpatient or outpatient during the study period (HR of 8.0 (95% CI 7.0 to 9.2)). Seven out of 11 main groups of diagnoses were affected, including 'Lens', 'Choroid and retina', 'Ocular muscles, binocular movement, accommodation and refraction', 'Glaucoma', Visual disturbances and blindness', 'Vitreous body and globe', and 'Sclera, cornea, iris and ciliary body'. The number of surgical procedures as well as the use of ophthalmic medication in patients with MFS was significantly increased. CONCLUSION: This nationwide epidemiological study of ocular morbidity in MFS demonstrates a profound burden and emphasises the need for thorough and experienced ophthalmological surveillance.

Current clinical practice in corneal crosslinking for treatment of progressive keratoconus in four Nordic countries.

PURPOSE: To evaluate clinical practice in the diagnosis and treatment of progressive keratoconus with corneal crosslinking (CXL) in four Nordic countries. METHODS: A questionnaire was sent to all centres at which keratoconus patients are evaluated and CXL is performed in Sweden, Denmark, Norway and Iceland. Nineteen of 20 centres participated. RESULTS: CXL is performed approximately 1300 times per year in these four Nordic countries with a population of around 21.7 million (2019). In most cases, progression is evaluated using the Pentacam HR, and the maximum keratometry reading (Kmax ) is considered the most important parameter. The most frequently used treatment protocol in Scandinavia is the 9 mW/cm2 epi-off protocol, using hydroxylpropyl methylcellulose riboflavin (HPMC-riboflavin). The participants deemed the following areas to be in most need of improvement: adaptation of the CXL protocol to individual patients (5/19), the development of effective epi-on treatment protocols (4/19), optimal performance of CXL in thin corneas (4/19), improvement of the definition of progression (2/19), and diagnosis of the need for re-treatment (2/19). CONCLUSIONS: We concluded that the diagnosis of progressive keratoconus and the diagnostic equipment used are similar. Treatment strategies are also similar but are suitably different to provide an interesting basis for the comparison of treatment outcomes. The high degree of participation in this survey indicates the possibility of future scientific collaboration on CXL focusing on the areas deemed to need improvement. It would also be of interest to evaluate the possibility of creating a Nordic CXL Registry. The high number of CXL treatments performed ensures sufficient statistical power to solve many questions. Such a registry could be an important contribution to evidence-based care and would allow for longitudinal evaluation.

Corneal transplantation in aniridia-related keratopathy with a two-year follow-up period, an uncommon disease with precarious course.

PURPOSE: The purpose of this study is to study the frequency, surgical transplantation technique and outcome in patients with aniridia-related keratopathy (ARK) with two-year follow-up period. METHODS: A retrospective registry-study including all ARK cases performed in Sweden and Denmark between 2001 and 2016 and registered in the Swedish Cornea Transplant Registry. RESULTS: A total of 36 eyes of 26 patients were subjected to corneal transplantation due to ARK during 2001 to 2016. Penetrating keratoplasty (PK) was the procedure of choice in 58.3% (n = 21) of the eyes, followed by a combination of PK and limbal stem cell transplantation in 13.9% (n = 5) and keratolimbal allograft in 13.9% (n = 5). Boston keratoprosthesis was used in 8.3% (n = 3), and anterior lamellar keratoplasty in 5.6% (n = 2). Thirteen of the procedures (36.1%) were retransplantations. Two years after surgery 26 cases were available to follow-up of which 16 of the grafts were functioning (61.5%). The median visual acuity showed a trend of improvement from hand motion to counting fingers. CONCLUSIONS: A majority of the ARK cases (61.5%) had a graft providing useful vision for the patient 2 years after corneal transplantation, but the visual gain was modest at best. Longer follow-up time is required to evaluate functional graft outcomes. Despite the introduction of limbal stem cell transplantation as a suitable treatment, PK was the most common surgical method in the present study.

Revealing the presence of tear extracellular vesicles in Keratoconus.

Extracellular vesicles (EVs) are lipid-bound vesicles that originate from the endosomal system or budded off from the plasma membrane. EVs are involved in cell-cell communication via transporting DNA, RNA, and proteins from one cell to another. Tear EVs (tEVs) have been reported in dry eye, SjÓ§gren's Syndrome, and primary open-angle glaucoma. In this study, we sought to investigate the presence of tEVs in relation to keratoconus (KC). Tears were passively collected from the lateral meniscus from 10 healthy (5 males and 5 females) and 9 KC (4 males and 5 females) subjects. Tear samples were processed and analyzed using the ExoView™ R100. Statistical analysis was performed using a Mann-Whitney U non-parametric Student's t-test. All tEVs, in both Healthy and KC subjects, showed a CD9+ dominant tEV cohort independent of sex. A significant decrease in CD63+/CD9+ and CD63+/CD81+/CD9+ was found in the male KC tEVs (p < 0.05), but not in females compared to their healthy counterparts. Neither Healthy nor KC tEVs showed differences in the total number of tEVs, however significant differences were identified between the sexes (p < 0.05), with males having a higher number of tEVs. tEVs diameters ranged from 50 to 200 nm, in both Healthy and KC cohorts, with the majority in the 50-80 nm range suggesting exosome-dominant cohorts. To our knowledge, this is the first time, to date, that tEVs have been isolated and characterized in KCs. While further studies are warranted, the tEVs differences between KC and Healthy subjects suggest a potential role for tEVs in KC pathogenesis.