Targeted next-generation sequencing analysis in Italian patients with keratoconus.

OBJECTIVE: To report variants in 26 candidate genes and describe the clinical features of Italian patients with keratoconus (KC). SUBJECTS/METHODS: Sixty-four patients with a confirmed diagnosis of KC were enrolled in this genetic association study. Patients were classified into two study groups according to whether they had a confirmed diagnosis of progressive or stable KC. A purpose-developed Next Generation Sequencing (NGS) panel was used to identify and analyse the coding exons and flanking exon/intron boundaries of 26 genes known to be associated with KC and corneal dystrophies. Interpretation of the pathogenic significance of variants was performed using in silico predictive algorithms. RESULT: The targeted NGS research identified a total of 167 allelic variants of 22 genes in the study population; twenty-four patients had stable keratoconus (n. 54 variants) and forty patients had progressive disease (n. 113 variants). We identified genetic variants of certain pathogenic significance in five patients with progressive KC; in addition, eight novel genetic variants were found in eight patients with progressive KC. Mutations of FLG, LOXHD1, ZNF469, and DOCK9 genes were twice more frequently identified in patients with progressive than stable disease. Filaggrin gene variants were found in 49 patients (76% of total), of whom 32 patients (80% of progressive KC group) had progressive disease. CONCLUSIONS: Targeted NGS research provided new insights into the causative effect of candidate genes in the clinical phenotype of keratoconus. Filaggrin mutations were found to represent a genetic risk factor for development of progressive disease in Italy.

Prediction of total corneal power in keratoconus using anterior surface data.

CLINICAL RELEVANCE: 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. BACKGROUND: 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. METHODS: 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. RESULTS: 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%). CONCLUSION: 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.

Comparison between IOL MASTER 500 and MYAH with vector analysis in low and mild anterior corneal astigmatism.

PURPOSE: Evaluate the agreement between IOL Master 500 (Carl Zeiss Meditec AG, Germany) and MYAH (Topcon EU, Visia Imaging, Japan) in measuring axial length, keratometry, and anterior corneal astigmatism. SETTING: Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Ophthalmology Clinic, University of Messina, Messina, Italy. METHODS: In this prospective study, 40 eyes (right eye 25, left eye 15) of 40 patients were included. Axial length (AL), keratometry (K1, K2), and anterior corneal astigmatism (ACA) were measured. AL, mean K (Kavg) and magnitude of ACA were compared using Bland - Altman plot analysis, parametric and nonparametric statistical analysis. The difference vector and angle of error of the ACA measured by the two devices were evaluated by vector analysis using polar diagrams. RESULTS: Mean and standard deviation with IOL Master and with MYAH device was for AL 24.25 ± 1.22 mm and 24.25 ± 1.22 mm (p = .99), for Kavg 42.75 ± 1.53 D and 42.85 ± 1.52 D (p = .78), for Magnitude of ACA 1.00 ± 0.58 D and 0.89 ± 0.56 D (p = .38) respectively. High correlations were found for AL (R² = 0.999), Kavg (R² = 0.996), and ACA Magnitude (R² = 0.889). Bland-Altman analysis of the two devices found high agreement and absence of proportional bias (MYAH-IOL MASTER) were found between the two assessments for AL (bias = -0.0005 mm, p = .93), Kavg (bias = 0.0955 D, p = .76) and ACA (bias = 0.11 D, p = .41). Limit of agreement (upper/lower LoA, 95%CI) were respectively +0.057/-0.058 mm for AL, + 0.29/-0.09 D for Kavg and +0.49/-0.27 D for ACA. No statistical difference was found between the x-component and y-component of the ACA vector (p > .01), the difference vector (IOL MASTER-MYAH) was +0.14 D axis 159 with an absolute mean angle of error of 7.2 ± 7.5 degree. CONCLUSIONS: The instruments appear to be interchangeable for measurements of AL, keratometry, and magnitude of ACA with high agreement between the two devices. Also, in the presence of low astigmatism, the two instruments give the same results in terms of ACA.

One-Year Results of Photorefractive Keratectomy for Myopia and Compound Myopic Astigmatism with 210 nm Wavelength All Solid-State Laser for Refractive Surgery.

BACKGROUND: To examine the 12-month clinical and refractive outcomes of PRK performed with a UV all-solid-state laser. METHODS: The study included healthy patients with myopia and/or compound myopic astigmatism enrolled for refractive surgery and treated with PRK using a 210 nm wavelength, 2 kHz repetition rate, UV all-solid-state laser (LaserSoft, Katana Technologies GmbH, Kleinmachnow, Germany). All subjects were examined at baseline and after 1, 3, 6, and 12 months after the treatment with a slit lamp, refraction, visual acuity assessment (logMAR chart), tonometry, ophthalmoscopy, and corneal tomography with a Scheimpflug camera. The outcome measures considered were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, central corneal thickness, and transparency. The efficacy, safety, predictability, and stability were determined. RESULTS: The study included 34 eyes of 19 patients. The mean UDVA changed from 1.20 ± 0.43 to -0.05 ± 0.10 logMAR at 12 months, and the mean CDVA changed from -0.03 ± 0.06 to -0.06 ± 0.09 logMAR, respectively. The mean spherical equivalent (SE) changed from -4.90 ± 2.12 D to -0.01 ± 0.40 D and was within ±0.50 D of the intended correction in 91% of eyes and within ±1.00 D in 97% of eyes at 12 months. No eyes lost lines of visual acuity, and 64% of eyes gained one or more lines. CONCLUSIONS: PRK with the 210 nm wavelength, 2 kHz repetition rate, all-solid-state laser LaserSoft system proved to have good visual, refractive, and clinical outcomes after the follow-up at 12 months. The emerging gas-free, solid-state technology might be considered a valid alternative for the gas operating lasers for corneal refractive surgery.

Neurotrophic Keratopathy in Systemic Diseases: A Case Series on Patients Treated With rh-NGF.

Purpose: To evaluate the prevalence, clinical ocular presentation and corneal healing in moderate and severe neurotrophic keratopathy (NK) caused by systemic diseases and treated with rh-NGF. Setting: Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Ophthalmology Clinic, University of Messina, Italy. Design: Retrospective observational study of case series. Materials and Methods: In this retrospective observational study 11 patients (five female and six males) aged from 24 to 88 years (55.4 ± 21.3 years) with moderate and severe NK caused by systemic diseases were enrolled. The VAS questionnaire was dispensed. The ocular examination comprised slit lamp evaluation, ocular surface assessment with Keratograph 5M (Oculus, Germany), corneal sensitivity with Cochet-Bonnet esthesiometer (Lunneaux, France) and corneal thickness measurement with AC-OCT (DRI, Triton, Topcon, Japan). The underlying systemic causes of NK were determined. Results: The main cause of NK was post-neuroma surgery (36%), followed by diabetes (18%). The remaining causes were rheumatoid arthritis (9%), post-traumatic (9%), post-surgery (9%), atopia (9%), Graves' disease (9%). Seven eyes presented severe grade of NK with corneal ulcer and in four a moderate grade was registered. The rh-NGF (Cenegermin) was administered with a standard protocol one drop six times daily for 8 weeks. The complete healing of all corneal defects was registered at the end of the treatment. Conclusions: The post-neuroma surgery was the most common cause of NK and severe grade was clinically more represented. The rh-NGF proved effective to promote corneal recovery with all defects healed after the treatment.

Double safe suture during cataract surgery on post radial keratotomy patients using clear corneal incisions.

PURPOSE: the aim of this study is to find a safer surgical approach in cataract surgery on eyes previously treated with radial keratotomy using clear corneal incisions. SETTING: Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Ophthalmology Clinic, University of Messina, Messina, Italy. DESIGN: Prospective study. METHODS: A prospective study was conducted on a group of 20 patients, 21 eyes with 16 RK incisions were evaluated for cataract phacoemulsification. Samples were divided into two groups: Group 1 underwent surgery with pre-operative one corneal stitch along radial keratotomy incisions near the main access site whereas Group 2 underwent modified surgery with two corneal stitches. RESULTS: After surgery, visual acuity, corneal hysteresis and corneal strength was evaluated. In all cases, an increased visual acuity was observed. Group 1 showed an UCVA of logMAR 0.22 ± 0.14, while group 2 presented a logMAR of 0.1 ± 0.07. Data did not show a statistically significant difference in UCVA after surgery between the two groups (P = 0.133). Instead, a significant difference in corneal hysteresis (CH), respectively with values of 8.65 ± 1.6 mmHg in group 1 and 9.2 ± 1.8 in group 2 (P = 0.031), and a corneal resistance factor (CRF) with values of 7.87 ± 1.4 mmHg in the first group and 8.65 ± 1.6 mmHg in the second one (P = 0.039) was observed. CONCLUSIONS: Double safe suture technique offers better stabilization of corneal structure during surgery in patients preventively treated with 16 incisions RK.