Keratoconus results in an increase in anterior and posterior curvatures and a reduction in corneal thickness. Anterior corneal ectasia is partially compensated by remodelling the corneal epithelium. ...Therefore, there is an alteration in the relationship between corneal surfaces and variation in corneal power. The variation in corneal power is one of the sources that induces errors in IOL power calculation.
This study aimed to assess a method for predicting total corneal power in keratoconus using several anterior surface parameters at 3 mm and 4 mm.
Tomographic data obtained using Pentacam (Oculus, Germany) were analysed from 280 eyes of 140 patients with keratoconus using anterior and posterior keratometry, anterior Q-value at 8 mm, central corneal thickness, Kmax location and value, and true net power at 4 mm (TNP). Calculated total corneal power (TCPc) at 3 mm was obtained using the Gauss formula. Predicted total corneal power at 3 mm (TCPp3) and 4 mm (TCPp4) was obtained from univariate (TCPp3u and TCPp4u) and multivariate linear regression formulae (TCPp3m and TCPp4m). SimK, anterior Q-value, vertical location, and Kmax value were used in the multivariate formulae. Mean absolute error (MAE) and median absolute error (MedAE) were also calculated. Absolute frequencies within dioptric ranges of all formulas divided for keratoconus grading were evaluated.
TCPc and TNP exhibited a good correlation (R2 = 0.58, p < 0.05) with a higher dispersion above 50 D of corneal power. Highly significant correlations were observed between TCPp3u and TCPc (R2 = 0.978, p < 0.05) and TCPp3m and TCPc (R2 = 0.989, p < 0.05). Lower but significant correlations were observed between TCPp4u and TNP (R2 = 0.692, p < 0.05) and between TCPp4m and TNP (R2 = 0.887, p < 0.05). The best results for TCP prediction at 3 and 4 mm were obtained with TCPp3m and TCPp4m as follows: MAE of TCPp3m was 0.24 ± 0.20 (SD) D with MedAE of 0.20 D, while MAE of TCPp4m was 0.96 ± 0.77 D with MedAE of 0.80 D. The 3 mm multivariate regression formula results in higher absolute frequencies of prediction errors in the total eyes within 0.5 D (93%) than the univariate formula (81%). At 4mm, the multivariate regression formula has a lower percentage within 0.5 D (32%) than the univariate formula (41%), but the percentage of the multivariate formula is higher within 1 D (63%) than the univariate formula (56%).
All formulas show a decrease in accuracy with increasing grades of keratoconus. Multivariate linear regression formulae using only anterior surface data can predict TCP with good approximation in eyes with keratoconus in cases where posterior surface parameters are unavailable. The vertical location of Kmax and the anterior asphericity could play a relevant role in the prediction of total corneal power in keratoconus.
To evaluate the clinical characteristics of pediatric patients with progression of keratoconus after accelerated iontophoresis-assisted epithelium-on corneal cross-linking (I-ON CXL) and to assess ...the efficacy and safety of re-treatment using accelerated epithelium-off CXL (epi-OFF CXL).
Sixteen eyes of 16 patients (mean age: 14.6 ± 2.5 years) with keratoconus underwent I-ON CXL. The main outcome measures were uncorrected distance visual acuity, corrected distance visual acuity, maximum keratometry index (Kmax), minimum corneal thickness, elevation front and elevation back measured at the thinnest point, total higher order aberrations root main square (HOA RMS), coma RMS, and spherical aberration. An increment of Kmax greater than 1.00 diopter (D) and a decrease of greater than 20 µm in pachymetry were considered to determine the progression of keratoconus. Patients with progression of keratoconus after I-ON CXL were re-treated using an epi-OFF CXL protocol.
Two years after I-ON CXL, 12 patients showed progression of keratoconus, whereas 4 patients were stable. There was significant worsening of Kmax (
= .04) and steepest keratometric reading (
= .01). Furthermore, a significant correlation was documented between progression of keratoconus and age (
= .02). These patients were re-treated using an epi-OFF protocol and after 2 years all patients were stable, and a statistically significant reduction of the mean Kmax (
= .007), HOA RMS (
= .05), and coma RMS (
= 05) was observed.
I-ON CXL was ineffective in the treatment of pediatric keratoconus in younger children, whereas it had an efficacy of 2 years in older children. Re-treatment using epi-OFF CXL proved effective to halt progression of keratoconus after I-ON CXL failure.
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The purpose of this study was to analyze corneal sub-basal nerve plexus (SBNP) density and morphology and their relationships with corneal parameters and refractive status. In this single center ...study, in vivo confocal microscopy (IVCM) was performed in 76 eyes of 38 healthy subjects aged 19-87 (mean age 34.987 ± 1.148). Nerve fiber analysis was performed using Confoscan 4 microscope with semi-automated software (Nidek Technologies, Italy) The nerve fiber length (NFL) µm/mm
, nerve fiber density (NFD) no./mm
, tortuosity coefficient (TC), and nerve beadings density (NBD) no./mm were considered. Relationship between SBNP parameters and corneal curvature, thickness, diameter, and refraction were analyzed. Additionally, the association with gender, laterality and age were determined. NFL was inversely correlated with age (r = - 0.528, p < 0.001), myopic refractive error (spherical value) (r = - 0.423, p < 0.001), and cylindrical power (r = - 0.340, p = 0.003). NFD was inversely correlated with age (r = - 0.420, p < 0.001) and myopic refractive error (r = - 0.341, p = 0.003). NBD showed a low inverse correlation with cylindrical power (r = - 0.287, p = 0.012) and a slight positive correlation with K (r = 0.230, p = 0.047). TC showed a significant negative correlation between age (r = - 0.500, p < 0.001) and myopic refractive error (r = - 0.351, p = 0.002). Additionally, there were strong positive correlations between NFL and NFD (r = 0.523, p < 0.001), NFL and TI (r = 0.603, p < 0.001), and NFD and TC (r = 0.758, p < 0.001). Multiple regression analysis revealed age to be the most significant factor affecting SBNP density (B = - 0.467, p = 0.013) and length (B = - 61.446, p < 0.001); myopic refractive error reduced both SBNP density (B = - 2.119, p = 0.011) and length (B = - 158.433, p = 0.016), while gender and laterality had no significant effects (p > 0.005). SBNP fiber length decreases with age, myopic refractive error and cylindrical power. SBNP fiber density reduces with age and myopic refractive error. Corneal nerve parameters are not influenced by gender or laterality.
: Grain food consumption is a trigger of gluten related disorders: celiac disease, non-celiac gluten sensitivity (NCGS) and wheat allergy. They demonstrate with non-specific symptoms: bloating, ...abdominal discomfort, diarrhea and flatulence. Aim: The aim of the review is to summarize data about pathogenesis, symptoms and criteria of NCGS, which can be helpful for physicians.
: The PubMed and Google Scholar databases were searched in January 2019 with phrases: 'non-celiac gluten sensitivity', non-celiac gluten sensitivity', non-celiac wheat gluten sensitivity', non-celiac wheat gluten sensitivity', and gluten sensitivity'. More than 1000 results were found. A total of 67 clinical trials published between 1989 and 2019 was scanned. After skimming abstracts, 66 articles were chosen for this review; including 26 clinical trials. Results: In 2015, Salerno Experts' Criteria of NCGS were published. The Salerno first step is assessing the clinical response to gluten free diet (GFD) and second is measuring the effect of reintroducing gluten after a period of treatment with GFD. Several clinical trials were based on the criteria.
: Symptoms of NCGS are similar to other gluten-related diseases, irritable bowel syndrome and Crohn's disease. With Salerno Experts' Criteria of NCGS, it is possible to diagnose patients properly and give them advice about nutritional treatment.
The cornea's intense innervation is responsible for corneal trophism and ocular surface hemostasis maintenance. Corneal diabetic neuropathy affects subbasal nerve plexus, with progressive alteration ...of nerves' morphology and density. The quantitative analysis of nerve fibers can be performed with in vivo corneal confocal microscopy considering the main parameters such as corneal nerve fibers length, corneal nerve fibers density, corneal nerve branching density, tortuosity coefficient, and beadings frequency. As the nerve examination permits the detection of early changes occurring in diabetes, the invivo corneal confocal microscopy becomes, over time, an important tool for diabetic polyneuropathy assessment and follow-up. In this review, we summarize the actual evidence about corneal nerve changes in diabetes and the relationship between the grade of alterations and the duration and severity of the disease. We aim at understanding how diabetes impacts corneal nerves and how it correlates with sensorimotor peripheral polyneuropathy and retinal complications. We also attempt to analyze the safety of the most common surgical procedures such as cataract and refractive surgery in diabetic patients and to highlight the specific risk factors. We believe that information about the corneal nerve fibers' condition obtained from the in vivo subbasal nerve plexus investigation may be crucial in monitoring peripheral small fiber polyneuropathy and that it will help with decision-making in ophthalmic surgery in diabetic patients.
Low-invasive in vivo solid-phase microextraction (SPME) was used to investigate the lipid profiles of muscle tissue of living fish. Briefly, mixed mode SPME fibers were inserted into the muscle for ...20 min extraction, and then the fibers were desorbed in an optimal mixture of solvents. The obtained lipid profile was then compared and contrasted to that obtained with employment of ex vivo SPME and solid-liquid extraction (SLE) from fish muscle tissue belonging to the same group of fish, following a one-year storage period. Ex vivo SPME analysis of stored muscle samples revealed 10-fold decrease in the number of detected molecular features in comparison to in vivo study. Moreover, in vivo microsampling enabled the identification of different classes of bioactive lipids, including fatty acyls, not present in the lipid profile obtained through ex vivo SPME and SLE, suggesting the alterations occurring in the unbound lipid fraction of the system under study during the storage and also indicating the advantage of the in vivo extraction approach.
The identification of new biomarkers of ocular diseases is nowadays of outmost importance both for early diagnosis and treatment. Epigenetics is a rapidly growing emerging area of research and its ...involvement in the pathophysiology of ocular disease and regulatory mechanisms is of undisputable importance for diagnostic purposes. Environmental changes may impact the ocular surface, and the knowledge of induced epigenetic changes might help to elucidate the mechanisms of ocular surface disorders. In this pilot study, we investigated the impact of extensive contact lens (CL) wearing on human corneal epithelium epigenetics. We performed ex vivo analysis of the expression of the miR-320 and miR-423-5p involved in the processes of cellular apoptosis and chronic inflammation. The human corneal epithelium was harvested from healthy patients before the photorefractive keratectomy (PRK). The patients were divided into two age- and sex-matched groups accordingly to CL wearing history with no CL wearers used as a control. The epithelium was stored frozen in dry ice at −80 °C and forwarded for miRNA extraction; afterwards, miRNA levels were detected using real-time PCR. Both miRNAs were highly expressed in CL wearers (p < 0.001), suggesting epigenetic modifications occurring in chronic ocular surface stress. These preliminary results show the relationships between selected miRNA expression and the chronic ocular surface stress associated with extensive CL use. MicroRNAs might be considered as biomarkers for the diagnosis of ocular surface conditions and the impact of environmental factors on ocular surface epigenetic. Furthermore, they might be considered as new therapeutic targets in ocular surface diseases.
Aim of this retrospective study was to estimate the effect of oral supplementation with amino acids (AA) on corneal nerves regrowth after excimer laser refractive surgery with photorefractive ...keratectomy (PRK). Based on the pre and post-surgical treatment received, 40 patients with 12 months of follow-up were distributed in two groups: 20 patients had received oral AA supplementation 7 days before and 30 days after PRK, and 20 patients without AA supplementation, as untreated reference control. All patients followed the same standard post-operative topical therapy consisting of an association of antibiotic and steroid plus sodium hyaluronate during the first week, then steroid alone progressively decreasing during 30 days and sodium hyaluronate for the following 3 months.
In vivo
corneal confocal microscopy was used to evaluate the presence of sub-basal corneal nerve fibers during 12 months after PRK. Results have shown that sub-basal nerves regenerated significantly faster (
p
<0.05), and nerve fibers density was significantly higher (
p
<0.05) with a more regular pattern in the eyes of AA treated patients with respect to the untreated control group. Therefore, our data indicate that oral supplementation with AA improved significantly corneal nerve restoration after PRK and could thus be considered as an additional treatment during corneal surgical procedures.
To report the clinical and confocal findings of a unique case of combined Phialemonium curvatum and Acanthamoeba keratitis and to highlight the role of the prompt diagnosis and specific medical ...treatment in preserving visual function.
A case report and literature review.
A 54-year-old woman presented with a 3-day history of visual impairment, photophobia, and ocular pain in her right eye. Her best corrected visual acuity was 0.4 Logarithm of the Minimum Angle of Resolution scale, and the slit-lamp examination showed whitish corneal stromal infiltrate with satellite lesions. In vivo confocal microscopy evidenced Acanthamoeba cysts and fungal hyphae that resulted P. curvatum in the culture examination. The intensive medical treatment was started with topical 0.02% polyhexamethylene biguanide, voriconazole 1%, and moxifloxacin hydrochloride 0.5%. Progressive improvement of clinical and confocal pictures was registered with a complete recovery of visual function after 1 month.
This is the first case report of combined P. curvatum and Acanthamoeba keratitis. The fast diagnosis with in vivo confocal microscopy allowed early and intensive specific treatment with recovery of corneal infection.
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