Vision Rehabilitation with a Native Pintucci-type Keratoprosthesis.

PURPOSE: To report visual rehabilitation with a native Pintucci keratoprosthesis (KPro) after a severe ocular surface chemical burn in a male patient. CASE REPORT: A 41-year-old man experienced a bilateral severe chemical burn 5 years previously. Earlier penetrating keratoplasty and keratolimbal allografts were unsuccessful in both eyes, and neither of the eyes had vision better than light perception. Both corneas were opaque and conjunctivalized. Because of severe dry eye and total limbal stem cell deficiency, the left eye was considered for a Pintucci-type KPro. In the first stage, the ocular surface was reconstructed with an oral mucus membrane graft, and a KPro was placed under the skin and orbicularis oculi muscle. Three months later, the KPro was removed and implanted in the left eye. During seven months after the KPro implantation, the anatomical position was acceptable, and his best corrected visual acuity was 2/10. CONCLUSION: Bearing in mind the successful results of the native Pintucci KPro in this case of severe acid burn, using this type of keratoprosthesis in patients with total limbal stem cell deficiency and severe dry eye is recommended.

Comparison of Graft Thickness Measured by an Eye Bank With Graft Thickness Measured After Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: To compare donor lenticule thickness reported by the eye bank with lenticule thickness measured at 6 months after Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: This prospective, interventional case series enrolled 30 eyes from 30 patients who underwent DSAEK using precut eye bank tissue. Preoperative thickness measurements of the donor lenticules were taken centrally and at pericentral and peripheral graft areas using an anterior segment optical coherence tomography system. The same measurements were repeated 6 months postoperatively. The preoperative and postoperative values were compared, and the relationships between these measurements were investigated using Pearson correlation coefficients. RESULTS: The mean donor age was 47.7 ± 10.7 years. The mean preoperative endothelial cell density was 3017 ± 361 cells/mm, which decreased to 1645 ± 482 cells/mm postoperatively (P < 0.001). The graft thickness of the precut tissue, as reported by the eye bank, was 136.8 ± 24.9 µm at the center, 149.4 ± 27.3 µm at the pericentral area, and 198.4 ± 32.8 µm at the periphery. The corresponding postoperative values were 119.2 ± 29.8 µm (P = 0.004), 124.5 ± 34.6 µm (P = 0.002), and 156.3 ± 45.4 µm (P < 0.001), respectively. The graft thickness measured by the eye bank was significantly associated with that measured in vivo at 6 months at the central (r = 0.63, P = 0.001) and pericentral (r = 0.50, P = 0.009) graft areas. However, the correlation between preoperative and postoperative peripheral graft thickness was insignificant (P = 0.14). CONCLUSION: Compared with preoperative values, central, pericentral, and peripheral graft thicknesses were reduced by 10.4%, 14.2%, and 18.4%, respectively, 6 months after DSAEK. Postoperative graft thinning was greater at the periphery compared with the central and pericentral areas.

Agreement Between Internal Astigmatism and Posterior Corneal Astigmatism in Pseudophakic Eyes.

PURPOSE: To directly measure internal astigmatism and evaluate its agreement with posterior corneal astigmatism in pseudophakic eyes. METHODS: This prospective study enrolled 32 eyes of 32 patients (18 women, 56.3%) who underwent phacoemulsification with implantation of a non-toric monofocal intraocular lens (IOL). Two months postoperatively, posterior corneal astigmatism was measured using a Pentacam Scheimpflug analyzer (Oculus Optikgeräte GmbH, Wetzlar, Germany). Manifest refractive astigmatism was measured after fitting a spherical hard contact lens. This refractive astigmatism that was vertexed to the corneal plane was considered internal astigmatism. The magnitudes of internal and posterior corneal astigmatism were compared. The relationship and agreement between these two astigmatisms were investigated using the Spearman correlation coefficient and Bland-Altman plots, respectively. RESULTS: The mean patient age was 56.3 ± 9.6 years. IOL decentration or tilt and posterior segment abnormalities were not encountered in any cases postoperatively. The mean refractive astigmatism measured before fitting the hard contact lens was -0.81 ± 0.56 diopters (D). Internal astigmatism (-0.17 ± 0.21 D) was significantly different from posterior corneal astigmatism (-0.30 ± 0.15 D; P = .046). Regression analysis demonstrated a weak association between internal astigmatism and posterior corneal astigmatism (r2 = 0.22, P = .013). Bland-Altman plots produced 95% limits of agreement for these two astigmatisms from -0.49 to 0.75 D. CONCLUSIONS: A significant but weak correlation was found between the magnitudes of internal astigmatism and posterior corneal astigmatism in the pseudophakic eyes. This result indicates that Pentacam measurement of the posterior cornea did not compare well with a "gold standard" of refraction-derived values. [J Refract Surg. 2018;34(6):379-386.].

Agreement between total corneal astigmatism calculated by vector summation and total corneal astigmatism measured by ray tracing using Galilei double Scheimpflug analyzer / Concordancia entre el astigmatismo corneal total calculado mediante sumación vectorial, y el astigmatismo corneal total medido mediante trazado de rayos utilizando un analizador Galilei de doble cámara Scheimpflug

Purpose: To evaluate the agreement between total corneal astigmatism calculated by vector summation of anterior and posterior corneal astigmatism (TCAVec) and total corneal astigmatism measured by ray tracing (TCARay). Methods: This study enrolled a total of 204 right eyes of 204 normal subjects. The eyes were measured using a Galilei double Scheimpflug analyzer. The measured parameters included simulated keratometric astigmatism using the keratometric index, anterior corneal astigmatism using the corneal refractive index, posterior corneal astigmatism, and TCARay. TCAVec was derived by vector summation of the astigmatism on the anterior and posterior corneal surfaces. The magnitudes and axes of TCAVec and TCARay were compared. The Pearson correlation coefficient and Bland-Altman plots were used to assess the relationship and agreement between TCAVec and TCARay, respectively. Results: The mean TCAVec and TCARay magnitudes were 0.76 ± 0.57 D and 1.00 ± 0.78 D, respectively (P < 0.001). The mean axis orientations were 85.12 ± 30.26◦ and 89.67 ± 36.76◦, respectively (P = 0.02). Strong correlations were found between the TCAVec and TCARay magnitudes (r = 0.96, P < 0.001). Moderate associations were observed between the TCAVec and TCARay axes (r = 0.75, P < 0.001). Bland-Altman plots produced the 95% limits of agreement for the TCAVec and TCARay magnitudes from -0.33 to 0.82 D. The 95% limits of agreement between the TCAVec and TCARay axes was -43.0 to 52.1◦. Conclusion: The magnitudes and axes of astigmatisms measured by the vector summation and ray tracing methods cannot be used interchangeably. There was a systematic error between the TCAVec and TCARay magnitudes

Objetivo: Evaluar la concordancia entre el astigmatismo corneal total calculado mediante suma de los vectores del astigmatismo corneal anterior y posterior (TCAVec), y el astigmatismo corneal total medido mediante trazado de rayos (TCARay). Métodos: Este estudio incluyó a un total de 204 ojos derechos de 204 sujetos normales. Los ojos se midieron utilizando un analizador Galilei de doble cámara Scheimpflug. Los parámetros medidos incluyeron el astigmatismo queratométrico simulado utilizando el índice queratométrico, el astigmatismo corneal anterior utilizando el índice refractivo corneal, el astigmatismo corneal posterior, y TCARay. TCAVec se calculó mediante la suma de los vectores del astigmatismo en las superficies corneales anterior y posterior. Se compararon las magnitudes y ejes de TCAVec y TCARay. Se utilizaron el coeficiente de correlación de Pearson y los diagramas de Bland-Altman para valorar la relación y concordancia entre TCAVec y TCARay, respectivamente. Resultados: Los valores medios de las magnitudes TCAVec y TCARay fueron 0,76 ± 0,57 D y 1 ± 0,78 D, respectivamente (P < 0,001). Las orientaciones medias del eje fueron 85,12 ± 30,26 grados y 89,67 ± 36,76 grados, respectivamente (P = 0,02). Se encontraron fuertes correlaciones entre las magnitudes de TCAVec y TCARay (r = 0,96, P < 0,001). Se observaron asociaciones moderadas entre los ejes de TCAVec y TCARay (r = 0,75, P < 0,001). Los diagramas de Bland-Altman establecieron un 95% de límite de acuerdo para las magnitudes de TCAVec y TCARay de -0,33 a 0,82 D. Los límites de acuerdo del 95% entre los ejes de TCAVec y TCARay fueron de -43 a 52,1 grados. Conclusión: Las magnitudes y ejes de los astigmatismos medidos mediante suma de vectores y trazado de rayos no pueden intercambiarse. Se produjo un error sistemático entre las magnitudes de TCAVec y TCARay

Mean Posterior Corneal Power and Astigmatism in Normal Versus Keratoconic Eyes.

PURPOSE: To compare mean posterior corneal power and astigmatism in normal versus keratoconus affected eyes and determine the optimal cut-off points to maximize sensitivity and specificity in discriminating keratoconus from normal corneas. METHODS: A total of 204 normal eyes and 142 keratoconus affected eyes were enrolled in this prospective comparative study. Mean posterior corneal power and astigmatism were measured using a dual Scheimpflug camera. Correlation coefficients were calculated to assess the relationship between the magnitudes of keratometric and posterior corneal astigmatism in the study groups. Receiver operating characteristic curves were used to compare the sensitivity and specificity of the measured parameters and to identify the optimal cut-off points for discriminating keratoconus from normal corneas. RESULTS: The mean posterior corneal power was -6.29 ± 0.20 D in the normal group and -7.77 ± 0.87 D in the keratoconus group (P < 0.001). The mean magnitudes of the posterior corneal astigmatisms were -0.32 ± 0.15 D and -0.94 ± 0.39 D in the normal and keratoconus groups, respectively (P < 0.001). Significant correlations were found between the magnitudes of keratometric and posterior corneal astigmatism in the normal (r=-0.76, P < 0.001) and keratoconus (r=-0.72, P < 0.001) groups. The mean posterior corneal power and astigmatism were highly reliable characteristics that distinguished keratoconus from normal corneas (area under the curve, 0.99 and 0.95, respectively). The optimal cut-off points of mean posterior corneal power and astigmatism were -6.70 D and -0.54 D, respectively. CONCLUSION: Mean posterior corneal power and astigmatism measured using a Galilei analyzer camera might have potential in diagnosing keratoconus. The cut-off points provided can be used for keratoconus screening.

Agreement between total corneal astigmatism calculated by vector summation and total corneal astigmatism measured by ray tracing using Galilei double Scheimpflug analyzer.

PURPOSE: To evaluate the agreement between total corneal astigmatism calculated by vector summation of anterior and posterior corneal astigmatism (TCAVec) and total corneal astigmatism measured by ray tracing (TCARay). METHODS: This study enrolled a total of 204 right eyes of 204 normal subjects. The eyes were measured using a Galilei double Scheimpflug analyzer. The measured parameters included simulated keratometric astigmatism using the keratometric index, anterior corneal astigmatism using the corneal refractive index, posterior corneal astigmatism, and TCARay. TCAVec was derived by vector summation of the astigmatism on the anterior and posterior corneal surfaces. The magnitudes and axes of TCAVec and TCARay were compared. The Pearson correlation coefficient and Bland-Altman plots were used to assess the relationship and agreement between TCAVec and TCARay, respectively. RESULTS: The mean TCAVec and TCARay magnitudes were 0.76±0.57D and 1.00±0.78D, respectively (P<0.001). The mean axis orientations were 85.12±30.26° and 89.67±36.76°, respectively (P=0.02). Strong correlations were found between the TCAVec and TCARay magnitudes (r=0.96, P<0.001). Moderate associations were observed between the TCAVec and TCARay axes (r=0.75, P<0.001). Bland-Altman plots produced the 95% limits of agreement for the TCAVec and TCARay magnitudes from -0.33 to 0.82D. The 95% limits of agreement between the TCAVec and TCARay axes was -43.0 to 52.1°. CONCLUSION: The magnitudes and axes of astigmatisms measured by the vector summation and ray tracing methods cannot be used interchangeably. There was a systematic error between the TCAVec and TCARay magnitudes.

Midterm outcomes of penetrating keratoplasty after cultivated oral mucosal epithelial transplantation in chemical burn.

PURPOSE: To evaluate the midterm outcomes of penetrating keratoplasty (PKP) after cultivated oral mucosal epithelial transplantation (COMET) in patients with bilateral total limbal stem cell deficiency (LSCD) due to chemical burn. METHODS: In this prospective interventional nonrandomized case series, optical PKP was performed in patients with severe stromal opacity after successful COMET. Main outcome measures were stability of the ocular surface, visual acuity improvement and corneal graft survival. RESULTS: Fourteen eyes of 14 patients with successful COMET were included. Time interval between PKP and COMET was 7.6 ± 1.3 months (6-9 months). Mean follow-up period was 28.2 ± 8 months (14-40 months, median 30 months). Epithelial healing was complete after 7 days in all eyes. Thirteen eyes had stable ocular surface without epithelial defect at final examination. The corneal surface had been covered by a transparent epithelium without significant neovascularization. Persistent epithelial defect developed in one eye 3 months after PKP which was considered as graft failure. Best-corrected visual acuity increased from 2.67 ± 0.08 LogMAR preoperatively to 0.64 ± 0.27 LogMAR after PKP (P < 0.001). Endothelial rejection occurred in four patients and was successfully managed by systemic and topical corticosteroids. Overall and rejection-free graft survival rates were 92.9 and 69.2%, respectively. CONCLUSION: PKP after COMET is a successful procedure which can be used to restore visual function in cases with bilateral total LSCD associated with severe stromal opacity due to chemical burns.

Aspheric versus wavefront-guided aspheric photorefractive keratectomy in eyes with significant astigmatism.

PURPOSE: To compare the refractive and higher-order aberrations (HOAs) outcomes after photorefractive keratectomy (PRK) in patients with significant astigmatism using aspheric versus wavefront-guided aspheric profiles. SETTING: Ophthalmic Research Center and Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Negah Eye Hospital, Tehran, Iran. DESIGN: Prospective randomized case series. METHODS: One eye of each patient with a refractive astigmatism more than 2.00 diopters (D) randomly received aspheric PRK. In the other eye, wavefront-guided and aspheric treatment was performed using a personalized treatment advanced algorithm. Visual acuity, refractive errors, and HOAs were compared between the 2 groups preoperatively and 12 months postoperatively. RESULTS: The study comprised 32 patients (64 eyes). The mean preoperative refractive astigmatism was -4.07 D ± 1.64 (SD) and -4.02 ± 1.55 D in the aspheric group and wavefront-guided aspheric group, respectively (P = .2). The mean postoperative astigmatism was -0.46 ± 0.37 D and -0.82 ± 0.53 D in the aspheric group and wavefront-guided aspheric group, respectively (P = .02). Postoperatively, the root mean square of total HOAs was significantly increased in both groups. However, compared with wavefront-guided aspheric PRK, aspheric PRK induced fewer HOAs (P = .003). CONCLUSIONS: In eyes with high astigmatism, post-PRK residual astigmatism was lower in the aspheric group than in the wavefront-guided aspheric group. The increase in HOAs was significantly higher in the wavefront-guided aspheric group than in the aspheric group.

Double-Ring Sign to Confirm Correct Orientation of Donor Lenticules During Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: To describe a sign that can confirm the correct position of donor lenticules during Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: In this clinical and laboratory study, DSAEK was performed in 3 eyes with a diagnosis of pseudophakic bullous keratopathy. Additionally, 2 whole globes and 2 precut corneoscleral buttons were procured for the purpose of the laboratory part of the study. After removal of recipient Descemet membrane, the donor graft was inserted into the anterior chamber, unfolded, and attached to the posterior corneal stroma with an air bubble. A similar procedure was performed in the eye-bank eyes with lenticules attached in both correct and upside-down orientations. RESULTS: After the anterior chamber was completely filled with air, 2 or more concentric shiny rings were formed at the border of the donor lenticule because of total internal reflection in the graft. In the live and eye-bank eyes with a donor graft attached in the correct orientation, the innermost shiny ring, indicating the stromal side of the graft, was observed under the recipient cornea, whereas the outermost ring, indicating the endothelial side, was formed deeper. When the donor lenticule was intentionally implanted upside down in the eye-bank eyes, the reverse situation occurred, and the largest ring was observed just beneath the recipient cornea. CONCLUSIONS: The correct anterior-posterior orientation of the donor lenticule during DSAEK could be identified by the shiny rings formed at the border of the graft after the anterior chamber was completely filled with air.

Corneal Changes After Collagen Crosslinking for Keratoconus Using Dual Scheimpflug Imaging.

PURPOSE: To evaluate corneal changes after collagen crosslinking (CXL) therapy for keratoconus (KCN) using the Galilei dual Scheimpflug analyzer. METHODS: This prospective, nonrandomized clinical study included 35 eyes of 32 keratoconus patients who had undergone CXL. The eyes were saturated with riboflavin solution and were subjected for 30 minutes to ultraviolet-A (UV-A) light with irradiance of 3 mW/cm(2). Effectiveness of the treatment was assessed by measuring uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest cylinder/sphere, keratometry, pachymetry, posterior and anterior elevations by the Galilei dual Scheimpflug analyzer. Prior to treatment and 8 months after therapy, Scheimpflug analysis was performed using the Galilei system. The four sets of data including keratometry values, pachymetry, elevation parameters and surface indices were statistically analyzed and compared. RESULTS: Mean patient age was 22.3 ± 3.8 years and mean postoperative follow-up was 8.1 ± 3.2 months. There was a significant increase in UCVA (0.54 ± 0.35 Log MAR preoperatively to 0.49 ± 0.34 LogMAR postoperatively, P = 0.01) and BCVA (0.21 ± 0.19 Log MAR preoperatively to 0.16 ± 0.17 LogMAR postoperatively, P = 0.01). Mean cycloplegic spherical equivalent refractive error was -4.13 ± 2.65 Diopter (D) preoperatively and - 4.67 ± 2.96 D postoperatively (P < 0.001). During the follow-up period, no significant difference was observed in pachymetric and elevation data postoperatively. CONCLUSION: Corneal stabilization could be achieved by collagen crosslinking therapy for keratoconus in terms of corneal thickness, keratometry values, elevation parameters and surface indices.