Multiple use of preservative-free single dose unit dexamethasone 0.1% eye drops is safe within 24 hours.

BACKGROUND: Unpreserved single-dose unit (SDU) eye drops are commonly used to avoid benzalkonium chloride-related toxicity. Although intended for single use, many patients report off-label repeated use of SDUs over a prolonged period. We investigated whether repeated use of dexamethasone 0.1% SDUs in the same patient increases the bacterial contamination rate. METHODS: We prospectively enrolled patients scheduled for inpatient corneal and glaucoma surgery receiving dexamethasone 0.1% SDU four times per day from the same vial. To assess contamination rates, one drop from the vial was cultured immediately after opening the SDU (t0), 10 hours later after four drop applications (t10) and 24 hours after opening without further drop applications (t24). Conjunctival swabs were taken before and after drop application. Contamination rate was assessed with a standard clinical culturing protocol without introducing a positive control. RESULTS: 110 eyes of 109 patients were evaluated. Drops collected immediately after opening the SDU (t0) were contaminated in 9/110 cultures (8.1%). At t10, 13/110 cultures were contaminated (11.8%; p=0.267) and 11/110 at t24 (10.0%; t24 vs t0; p=1.00). In 5 of 21 cases of contaminated drops at t10 and/or t24, the same isolates were cultured from the initial conjunctival swab and the SDU. In three cases, the same bacterial species was found in consecutive samples. CONCLUSION: The contamination rate of the SDU did not increase after multiple use within 24 hours. Contamination from fingertip flora was more likely than from ocular surface flora. Reuse of dexamethasone 0.1% SDU in the same patient within 24 hours appears to be safe.

Deep Learning Models Used in the Diagnostic Workup of Keratoconus: A Systematic Review and Exploratory Meta-Analysis.

PURPOSE: The prevalence of keratoconus in the general population is reported to be up to 1 of 84. Over the past 2 decades, diagnosis and management evolved rapidly, but keratoconus screening in clinical practice is still challenging and asks for improving the accuracy of keratoconus detection. Deep learning (DL) offers considerable promise for improving the accuracy and speed of medical imaging interpretation. We establish an inventory of studies conducted with DL algorithms that have attempted to diagnose keratoconus. METHODS: This systematic review was conducted according to the recommendations of the PRISMA statement. We searched (Pre-)MEDLINE, Embase, Science Citation Index, Conference Proceedings Citation Index, arXiv document server, and Google Scholar from inception to February 18, 2022. We included studies that evaluated the performance of DL algorithms in the diagnosis of keratoconus. The main outcome was diagnostic performance measured as sensitivity and specificity, and the methodological quality of the included studies was assessed using QUADAS-2. RESULTS: Searches retrieved 4100 nonduplicate records, and we included 19 studies in the qualitative synthesis and 10 studies in the exploratory meta-analysis. The overall study quality was limited because of poor reporting of patient selection and the use of inadequate reference standards. We found a pooled sensitivity of 97.5% (95% confidence interval, 93.6%-99.0%) and a pooled specificity of 97.2% (95% confidence interval, 85.7%-99.5%) for topography images as input. CONCLUSIONS: Our systematic review found that the overall diagnostic performance of DL models to detect keratoconus was good, but the methodological quality of included studies was modest.

Differences in minimal disease knowledge of keratoconus patients: results from an international survey.

BACKGROUND/AIMS: The objective of this multicentre, multinational, prospective study was to assess the level of basic understanding that individuals with keratoconus possessed about their condition. METHODS: We recruited 200 active keratoconus patients who were under regular review, and cornea specialists established a standard of 'minimal keratoconus knowledge' (MKK) that included an understanding of the definition, risk factors, symptoms and treatment options for the condition. We collected data from each participant regarding their clinical characteristics, highest level of education, (para)medical background and experiences with keratoconus within their social circle, and calculated the percentage of MKK attained by each patient. RESULTS: Our findings revealed that none of the participants met the MKK standard, with the average MKK score being 34.6% and ranging from 0.0% to 94.4%. Furthermore, our study showed that patients with a university degree, previous surgical intervention for keratoconus or affected parents had a higher MKK. However, age, gender, disease severity, paramedical knowledge, disease duration and best-corrected visual acuity did not significantly affect the MKK score. CONCLUSIONS: Our study demonstrates a concerning lack of basic disease knowledge among keratoconus patients in three different countries. The level of knowledge exhibited by our sample was only one-third of what cornea specialists would typically anticipate from patients. This highlights the need for greater education and awareness campaigns surrounding keratoconus. Further research is needed to determine the most efficient approaches for enhancing MKK and subsequently improving the management and treatment of keratoconus.

Accuracy of a New Noninvasive Automatic Ocular Surface Analyzer for the Diagnosis of Dry Eye Disease-Two-Gate Design Using Healthy Controls.

PURPOSE: The purpose of this study was to assess the diagnostic performance of measurements from a new noninvasive, automated ocular surface analyzer (IDRA) in the diagnosis of dry eye disease (DED). METHODS: We prospectively identified patients with and without DED using best practice methods. Subsequently, all participants underwent IDRA analysis, consisting of 5 components: noninvasive tear film break-up time, tear meniscus height, lipid layer interferometry, eye blink quality, and infrared meibography. The manufacturer provides cutoff values for a pathologic result for each of these components. Using a stepwise augmentation multivariate logistic regression model, we identified the components with the strongest association for the presence of DED. For the 3 components with the strongest association (interferometry, tear meniscus, and infrared meibography), we calculated the probability of DED. RESULTS: We enrolled 40 patients (80 eyes) with DED (mean age 60.5 years; women 78.3%) and 35 healthy subjects (70 eyes, mean age 31.1 years; women 21.7%). The IDRA had an area under the curve of 0.868 (95% confidence interval: 0.809-0.927) to detect DED. A normal (≥80) interferometry combined with a normal (>0.22) tear meniscus and a normal (≤40) infrared meibography was associated with an estimated probability of 18% for the presence of DED, whereas the estimated probability of DED was as high as 96% when all 3 findings were pathologic. CONCLUSIONS: The results of IDRA showed a positive concordance with routine clinical diagnostic tests. The new analyzer is an easy-to-access diagnostic tool to rule out the presence of DED in the extramural setting and to guide a timely DED treatment.

Agreement of intraocular lens power calculation between 2 SS-OCT-based biometers.

PURPOSE: To assess agreement of measurements by 2 swept-source optical coherence tomography biometers and to evaluate the prediction error (PE) in intraocular lens power calculation with 7 formulas. SETTING: Tertiary public eye hospital. DESIGN: Consecutive observational. METHODS: Axial length (AL), keratometry (K), anterior chamber depth (ACD), lens thickness (LT), and corneal diameter (CD) were measured with the IOLMaster 700 (Biometer A) and Anterion (Biometer B). Agreement was quantified by the limits of agreement and concordance correlation coefficient (CCC). The PE, the median absolute error, and the mean absolute error of the Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas were investigated after constant optimization. RESULTS: In 78 eyes from 78 patients, excellent agreement was obtained for AL (CCC >0.99), very good agreement for K, ACD, and LT (CCC >0.95), and strong agreement for CD (CCC >0.72). An additive offset of 0.07 mm was measured for ACD and LT whose mean values were higher with Biometer B (P < .001). No statistically significant difference was found between the PEs and their absolute values when comparing the results of each formula between the 2 biometers. CONCLUSIONS: Agreement of biometric measurements by the 2 biometers was high, although Biometer B provided higher mean values of ACD and LT by 0.07 mm. In cataract patients with normal eye length, measurements by the 2 biometers did not lead to different refractive outcomes with the 7 formulas investigated.

Distribution of preoperative angle alpha and angle kappa values in patients undergoing multifocal refractive lens surgery based on a positive contact lens test.

PURPOSE: To assess the preoperative objective angle alpha and angle kappa measurements of patients deciding to undergo multifocal refractive lens surgery based on a subjective positive multifocal contact lens test (MCLT). METHODS: Retrospective, consecutive case series. Alpha and kappa angles were measured using the iTrace aberrometer. All patients also performed a 1-week MCLT. Only patients with a positive MCLT underwent surgery. Visual outcome (UCVA) was obtained in the 1-year follow-up. We assessed the preoperative distribution of angle values within MCLT positive and negative patient groups. RESULTS: Two hundred seventeen eyes (111 patients) were included. Mean age was 56.4 years (SD 5.6) and 46.9% were female. In 71 eyes (38 patients), MCLT was positive. Of them, 12 eyes (17%) had an angle alpha and angle kappa ≥ 0.5mm. Of 146 eyes (73 patients) who refrained from surgery due to a negative MCLT, 71 eyes (48.6%) had both angles small (<0.5mm). In the 1-year follow-up, UCVA improved by 0.68 logMAR (SD 0.51; p<0.001) from baseline. Eyes with both small angle alpha and kappa sizes improved by 0.78 logMAR (SD 0.56), as did eyes with high (≥0.5mm) angle sizes (0.82 logMAR (SD 0.53). UCVA of eyes (n=24) with high alpha but low kappa sizes improved less (-0.31 logMAR (SD 0.13; p=0.019)). CONCLUSION: Four out of five patients with a positive MCLT also had correspondingly small angle values. One-half of patients with low preoperative angle values refrained from surgery due to a negative MCLT result. One-year visual acuity improvement was substantial and independent from angle sizes.

Multifocal Femto-PresbyLASIK in Pseudophakic Eyes.

BACKGROUND: Presbyopia treatment in pseudophakic patients with a monofocal IOL is challenging. This study investigates the refractive results of femto-PresbyLASIK and analyzes presbyopia treatment in pseudophakic eyes. METHODS: 14 patients with 28 pseudophakic eyes were treated with femto-PresbyLASIK. The dominant eye was targeted at a distance and the non-dominant eye at -0.5 D. The presbyopic algorithm creates a steepness in the cornea center by using an excimer laser that leads to corneal multifocality. RESULTS: 6 months after surgery a refraction of -0.11 ± 0.13 D (p = 0.001), an uncorrected distance visual acuity of 0.05 ± 1.0 logMAR (p < 0.001) and an uncorrected near visual acuity of 0.15 ± 0.89 logMAR (p = 0.001) were achieved in the dominant eye. For the non-dominant eye, the refraction was -0.28 ± 0.22 D (p = 0.002), the uncorrected distance of visual acuity was 0.1 ± 1.49 logMAR, and the uncorrected near visual acuity was 0.11 ± 0.80 logMAR (p < 0.001). Spherical aberrations (Z400) were reduced by 0.21-0.3 µm in 32% of eyes, and by 0.31-0.4 µm in 26% of eyes. CONCLUSION: By steepening the central cornea while maintaining spherical aberrations within acceptable limits, PresbyLASIK created a corneal multifocality that safely improved near vision in both eyes. Thus, femto-PresbyLASIK can be used to treat presbyopia in pseudophakic eyes without performing intraocular surgery.

Mismatch of corneal specialists' expectations and keratoconus knowledge in general ophthalmologists - a prospective observational study in Switzerland.

BACKGROUND: To assess whether Swiss general ophthalmologists have the minimal keratoconus knowledge that corneal specialists would expect them to have. METHODS: Corneal specialists defined "minimal keratoconus knowledge" (MKK) with respect to definition, risk factors, symptoms and possible treatment options of keratoconus. A telephone interview survey was conducted among one hundred ophthalmologists (mean age 51.9 years (SD 9.5), 60 % male) from the German-speaking part of Switzerland. For each participant, years of work experience, number of keratoconus patients seen per year and access to a topography device were obtained. We calculated the proportion of MKK and examined in multivariate analyses whether ophthalmologists with access to topography and with greater work experience performed better than other groups. RESULTS: No single ophthalmologist had MKK. The mean MKK was 52.0 %, and the range was 28.6-81.0 %. Per 10 years of working in private practice, the MKK decreased by 8.1 % points (95 % CI: -14.2, -2.00; p = 0.01). Only 24 % of participants correctly recalled the definition of keratoconus, 9 % all risk factors, 5 % all symptoms and 20 % all treatment modalities. The MKK values were not associated with the number of keratoconus patients seen per year and the availability of topography to diagnose keratoconus. CONCLUSIONS: There is a substantial mismatch between corneal specialist' expectations and general ophthalmologists' knowledge about keratoconus. The low recall of symptoms and risk factors may explain why ophthalmologists diagnose relatively few cases of keratoconus, resulting in inefficient care delivery and delayed intervention.

Do Patients With Keratoconus Have Minimal Disease Knowledge?

PURPOSE: To assess whether Swiss adult citizens diagnosed with keratoconus have the minimal knowledge that a corneal specialist would expect they should have. METHODS: Experts defined the "minimal keratoconus knowledge" (MKK) with respect to definition, risk factors, symptoms, and possible treatment options of keratoconus. A survey was performed in 167 patients with keratoconus [mean age 38.8 years (SD 13.9), 77.7% male] in 5 specialized institutions. Of each participant, salient clinical characteristics, highest educational level, paramedical background, and specific health experience with keratoconus in the social surrounding were obtained. We calculated the proportion of MKK and examined whether patients with higher education and greater disease experience would perform better than those from other groups in multivariate analyses. RESULTS: No single citizen reached 100% MKK. The mean MKK was 35.2%, and the range was 0% to 76.2%. Participants with a university degree had only a moderately higher MKK [+8.7% (95% confidence interval: 4.4-13.0); P < 0.001]. Per age decile, the MKK declined by 3.1% (95% confidence interval: 1.2-4.9), P = 0.002. Disease duration, severity of keratoconus in Kmax values, and history of surgical treatment did not significantly increase MKK. Surprisingly, MKK was also lower in patients with a paramedical background [-6.3% (-14.1 to 1.4); P = 0.107]. CONCLUSIONS: This sample of Swiss patients with keratoconus did not know more than a third of the MKK. We found a little difference within various subgroups. There is a substantial mismatch between caregivers' expectations of patients' knowledge and patients' active knowledge regarding their condition. This may lead to an inefficient care delivery and misunderstandings.

Don't be afraid of the dark - OCT angiography through a black intraocular lens.

PURPOSE: To report a case in which optical coherence tomography (OCT) and OCT angiography (OCT-A) allowed imaging of the posterior pole in a patient fitted with a black occlusive intraocular lens (IOL). OBSERVATIONS: Following retinal central artery occlusion, a 52-year-old patient suffered from disturbing residual light perception. Occlusive contact lenses blocked the light insufficiently, so that the patient had to rely on an eye patch for relief of symptoms. After no neovascularization had formed during an observation period of 12 months, a black IOL (Morcher 85F) was implanted, blocking wavelengths in the visible spectrum but allowing transmission in the near-infrared spectrum. Slit lamp photography, OCT and OCT-A were performed pre- and postoperatively. Postoperatively, slit lamp photography could no longer provide images of the posterior pole, proving the effective blockade of wavelengths in the visible light spectrum. In contrast, transmission in the near-infrared spectrum allowed for OCT and OCT-A imaging of the fundus. The complete suppression of the disturbing perception of light succeeded only temporarily. CONCLUSIONS AND IMPORTANCE: The implantation of a black IOL does not prevent the imaging of the retinal microvasculature by OCT-A. Black IOLs can therefore be considered even if continued monitoring of the vascular situation of the posterior pole is required.

Changes in higher order aberrations after central corneal regularization - a comparative two-year analysis of a semi-automated topography-guided photorefractive keratectomy combined with corneal cross-linking.

BACKGROUND: The optical quality in progressive keratoconus deteriorates due to ectasia and distortion of the corneal shape and optics. While corneal cross-linking (CXL) aims at stopping disease progression, "CXL-Plus" combines CXL with excimer laser ablation to improve visual function. Central Corneal Regularization (CCR) represents a therapeutic excimer laser modality specifically designed to smoothen the ectatic corneal shape and to reduce higher order aberrations (HOA). We set out to compare CXL-Plus, consisting of CXL combined with CCR, with CXL by itself for patients with progressive keratoconus. METHODS: Retrospective 2-year matched group analysis of patients who either underwent CXL-Plus (n = 28) or CXL as a sole procedure (n = 28) for progressive keratoconus. Main outcome parameters were HOA, visual function and tomographic results 12 and 24 months postoperatively. RESULTS: After 12 months, the total HOA root mean square wavefront error was reduced from 0.79 ± 0.30 to 0.40 ± 0.19 µm (CXL-Plus; p <  0.0001) and changed from 0.71 ± 0.28 to 0.73 ± 0.36 µm (CXL; p = 0.814). Uncorrected distance visual acuity improved from 0.70 ± 0.35 to 0.36 ± 0.29 logMAR (CXL-Plus; p = 0.0002) and from 0.65 ± 0.39 to 0.46 ± 0.37 logMAR (CXL; p = 0.067), translating to gains of three or more lines in 50% (CXL-Plus) and 36% (CXL) of patients. The steepest keratometry value (Kmax) regressed by 5.84 D (CXL-Plus; p <  0.0001) and 0.66 D (CXL; p = 0.752). For none of the investigated parameters a statistically significant change could be shown between 12 and 24 months. CONCLUSIONS: CXL-Plus in the form of a CCR reduces HOA and Kmax more effectively than CXL as a sole procedure.

Keratoconus Characteristics Used in Randomized Trials of Surgical Interventions-A Systematic Review.

PURPOSE: To investigate descriptions and inclusion criteria of keratoconus used in randomized trials assessing the efficacy of surgical and nonsurgical interventions. METHODS: Systematic review: we searched (Pre-)Medline and the Cochrane Library from inception until December 2018 and checked the reference lists of included articles and reviews. We included randomized trials assessing the efficacy of any kind of keratoconus treatment. No language restrictions were imposed. We assessed articles against the inclusion criteria, extracted relevant data including any kind of keratoconus description, and examined the methodological quality. RESULTS: Searches retrieved 459 nonduplicate records, and we included 57 randomized controlled trials investigating 9 different surgical interventions with the most used primary outcome measure being maximum keratometry. Only 15 (26.3%) described eligibility parameters regarding keratoconus staging/classification, of which 12 studies used the Amsler-Krumeich classification. Eleven studies were published before 1997 (before publication of the Consolidated Standards of Reporting Trials statement), and none of these described the use of a classification. From 1997 onward, 15 of 46 studies (32.6%) described the incorporation of a classification system (P = 0.051). The average methodological quality of included trails was modest. CONCLUSIONS: The evidence from randomized trials, even after introduction of the Consolidated Standards of Reporting Trials statement, remains ill-formed regarding a careful definition of keratoconus. This is unfortunate because imprecisions regarding the specification of included patients preclude clinicians to assess applicability, that is, the extent to which they can use inferences drawn from study participants regarding efficacy and adverse events in the care of individual patients.

Fluorophotometric Determination of Riboflavin Concentrations in a Human Artificial Anterior Chamber Model.

PURPOSE: Corneal cross-linking (CXL) requires an adequate corneal riboflavin impregnation, which is clinically assessed by verification of a riboflavin "flare" in the anterior chamber. We set out to replace this subjective assessment with an objective measurement method and evaluated fluorophotometry as an apparatus-based technique for riboflavin detection in the anterior chamber. METHODS: In an artificial anterior chamber model using human corneas and a modified Fluorotron fluorophotometer, we determined the detection limits of riboflavin concentrations across native corneas by comparison measurements of the same concentrations in glass cuvettes. Subsequently, standard CXL procedures with corneal application of riboflavin were simulated and the proportions of riboflavin entering the anterior chamber were measured fluorophotometrically. RESULTS: The measurement results of the riboflavin dilution series in the artificial anterior chamber showed a very high concordance with the results obtained in a glass cuvette (Pitman test P = 0.329). In the CXL simulation, the mean riboflavin concentration measured in the anterior chamber increased within 15 minutes from 5 (±1) to 903 (±204) ng/mL and stood at 1089 (±56) ng/mL after 30 minutes. CONCLUSIONS: Fluorophotometry is able to measure riboflavin in an artificial anterior chamber across human corneas over a wide range of concentrations and it reliably detects the increasing riboflavin signal in simulated CXL procedures. TRANSLATIONAL RELEVANCE: The replacement of the subjective riboflavin detection by a technically straightforward, objective detection method might increase patient safety and treatment efficiency in CXL.

Efficiency of video-presented information about excimer laser treatment on ametropic patients' knowledge and satisfaction with the informed consent process.

PURPOSE: To evaluate whether the presentation of a video within the informed consent consultation affects patient knowledge about refractive excimer laser treatment, satisfaction with the informed consent process, anxiety in respect to the planned surgery, and the consultation duration. SETTING: Tertiary referral center, Lucerne, Switzerland. DESIGN: Single-center, randomized controlled trial. METHODS: Consenting eligible patients were randomly assigned to receive either a conventional face-to-face consultation (conventional group) or a conventional consultation with additional video-assisted information (interventional group). Knowledge and satisfaction with the informed consent process and anxiety regarding surgery were assessed. Differences between groups were tested with Wilcoxon-Mann-Whitney, Chi-square, and Student t tests. RESULTS: The study comprised 113 patients (58 in the conventional group and 55 in the interventional group). There was no difference in terms of knowledge with 22/25 points (interquartile range [IQR], 3) in the conventional group versus 22/25 points (IQR, 2) in the interventional group (P = .957), satisfaction with the informed consent ("very satisfied": 47/58 versus 45/55; P = .915) and anxiety toward surgery with a median 8 (IQR, 4) versus median 9 (IQR, 3; P = .159). In the interventional group, however, the total consultation time was significantly lower than in the conventional group (-4.96 minutes; 95% CI, -9.50 to -0.43; P = .032). CONCLUSION: Compared with a conventional consultation, video-assistance slightly reduced the total consultation time while maintaining patient knowledge, satisfaction with the informed consent process, and anxiety regarding the surgery on equal levels. Video-assistance could increase efficiency of clinical management on a double-digit percentage at an equal running cost compared with a conventional consultation.

Variability of Tear Osmolarity Measurements With a Point-of-Care System in Healthy Subjects-Systematic Review.

PURPOSE: To assess the variability of osmolarity measured by the point-of-care TearLab system in healthy eyes. METHODS: A systematic review was performed by searching MEDLINE, Scopus, and the Web of Science Databases until November 2016 and checking reference lists of included articles and reviews. The requirements for inclusion were the availability of TearLab results in healthy subjects and a minimum study sample of 20 eyes. Two reviewers assessed articles against the inclusion criteria, extracted relevant data, and examined the methodological quality. We computed the weighted mean osmolarity using the study size as the weighting factor and calculated the rate of subjects with osmolarity values >308 mOsm/L, the Dry Eye Workshop Report 2017 (DEWS) cut-off value for dry eye disease (DED). We repeated the analysis after excluding reports with a possible conflict of interest or missing description of subject selection. RESULTS: Searches retrieved 105 nonduplicate articles, and we included 33 studies investigating 1362 eyes of healthy participants who were asymptomatic and showed no clinical signs of DED. Sixty-three percent were female, and mean age was 37.3 years (range: 21.5-69.0 yr). Weighted mean osmolarity was 298 mOsm/L (95% confidence interval, 282-321 mOsm/L). The result of the subgroup analysis was similar. Overall, 386 of 1362 eyes (28.3%) fulfilled the DEWS's definition of DED (>308 mOsm/L). CONCLUSIONS: There is a high variability of osmolarity measurements with the TearLab system. A substantial number of healthy subjects fulfill the DEWS's definition of DED. We propose interpreting the TearLab osmolarity results cautiously and in the context of other established methods.

Pediatric Corneal Cross-linking: Comparison of Visual and Topographic Outcomes Between Conventional and Accelerated Treatment.

PURPOSE: To compare visual and topographic outcomes 1 year after conventional (C-CXL) vs accelerated corneal cross-linking (A-CXL) in pediatric keratoconus (KC). DESIGN: Comparative, retrospective, consecutive case series. METHODS: Patients with topography-confirmed, progressive KC and a corneal thickness of ≥400 µm at the time of surgery were enrolled. Uncorrected (UCVA) and best phoropter-corrected visual acuity (BCVA) and normal maximum keratometry reading (Kmax) were measured at study entry and at the 12-month follow-up. Treatment failure rate was defined as the percentage of eyes with an increase in Kmax of more than 1.0 diopter during follow-up. The adverse event rate was the percentage of eyes with a loss of ≥2 Snellen lines of BCVA from baseline. This was a single-center analysis of 78 eyes of 58 patients that underwent C-CXL (39 eyes) and A-CXL (39 eyes). No eyes were lost to follow-up after 12 months. RESULTS: No significant difference between changes in 12 months after as compared to the time before CXL for UCVA (0.01 log MAR; 95% confidence interval -0.14 to 0.15, P = .944), BCVA (0.05 log MAR; 95% confidence interval -0.05 to 0.15, P = .310), and Kmax (-0.77 diopters; 95% confidence interval -2.20 to 0.65, P = .282) between the C-CXL and A-CXL group were observed. Treatment failure rate was observed in 9 of 39 eyes (23.1%) in C-CXL and in 6 of 39 eyes (15.4%) in A-CXL (P = .389). Adverse events were seen only in 1 eye in the C-CXL group. CONCLUSIONS: In this retrospective comparison, the accelerated approach was equally as effective as the conventional protocol to treat pediatric keratoconus.

Superiority of small islets in human islet transplantation.

Many factors influence the outcome of islet transplantation. As islets in the early posttransplant setting are supplied with oxygen by diffusion only and are in a hypoxic state in the portal system, we tested whether small human islets are superior to large islets both in vitro and in vivo. We assessed insulin secretion of large and small islets and quantified cell death during hypoxic conditions simulating the intraportal transplant environment. In the clinical setting, we analyzed the influence of transplanted islet size on insulin production in patients with type 1 diabetes. Our results provide evidence that small islets are superior to large islets with regard to in vitro insulin secretion and show a higher survival rate during both normoxic and hypoxic culture. Islet volume after 48 h of hypoxic culture decreased to 25% compared with normoxic culture at 24 h due to a preferential loss of large islets. In human islet transplantation, the isolation index (islet volume as expressed in islet equivalents/islet number), or more simply the islet number, proved to be more reliable to predict stimulated C-peptide response compared with islet volume. Thus, islet size seems to be a key factor determining human islet transplantation outcome.