Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy.

PURPOSE: To evaluate the outcome of sequential customized therapeutic keratectomy (SCTK) in reducing higher order aberrations (HOAs) and improving quality of vision in highly aberrated corneas consequent to previous radial keratotomy (RK). METHODS: A retrospective review of patients undergoing SCTK treatment from January 2012 to October 2020 was conducted in the Eye Center, Humanitas Clinical and Research Center (Rozzano, Italy). Indications for treatment in patients who had RK were significantly and/or progressively reduced corrected distance visual acuity (CDVA) combined with visual symptoms critically affecting quality of life. Preoperative and postoperative CDVA, corneal topography and aberrometry, Scheimpflug tomography, and anterior segment optical coherence tomography were registered. RESULTS: Thirty-four patients who underwent RK a mean of 26.62 ± 7.10 years before SCTK treatment were included. SCTK induced a significant improvement of CDVA from 0.44 ± 0.82 logMAR preoperatively to 0.15 ± 0.64 logMAR postoperatively (P < .001). No patient experienced worsening of CDVA, whereas 8 patients (23,50%) gained one line and 23 patients (67.65%) gained two lines or more. A significant decrease in corneal coma, trefoil, and spherical aberrations was also noted (P = .003, .003, and .004, respectively). CONCLUSIONS: SCTK proved to be a safe and effective option to treat highly aberrated eyes following RK. The authors suggest the use of SCTK as a first-line approach for the treatment of HOAs after RK and avoiding more invasive procedures such as corneal transplantation or intraocular lens implantation. [J Refract Surg. 2023;39(12):808-816.].

Corneal Collagen Cross-Linking for Progressive Keratoconus in Pediatric Patients: Up to 14 Years of Follow-up.

PURPOSE: To assess the long-term outcomes of corneal collagen cross-linking according to the Dresden protocol (S-CXL) in progressive pediatric keratoconus (KC). DESIGN: Retrospective, single-center noncomparative interventional study. METHODS: Patients aged <18 years who underwent S-CXL from June 2007 to January 2011 in Humanitas Clinical and Research Center, Rozzano, Milan, Italy, and completed at least 10 years of follow-up were included. Corrected distance visual acuity (CDVA), refraction, and tomography were evaluated at baseline and ≥10 years after S-CXL. Meeting 2 of the following 3 criteria indicated reprogression: progression above 95% CI for post-CXL population of A or B values or a decrease in minimal thickness C evaluated with the ABCD display. RESULTS: Thirty-eight eyes of 24 patients fulfilled inclusion criteria. At a mean of 11.6 years postoperation (maximum 14 years), the CDVA improved significantly (from 0.703 ± 0.33 decimal fraction to 0.887 ± 0.2, P < .001). Similarly, the A value significantly improved from 2.550 ± 1.7 to 1.627 ± 1.68 (P = .019). Thirteen eyes (34%) showed significant postoperative progression in 2 of the 3 parameters A, B, and C. Of these, only 3 eyes (7.9%) of 3 patients showed a statistically significant change in the A value. CONCLUSIONS: S-CXL proved to be a safe treatment for progressive KC in pediatric patients with an anterior curvature progression rate of up to 7.9% at ≥10 years of follow-up.

Corneal Biomechanics Assessment with Ultra High Speed Scheimpflug Camera in Primary Open Angle Glaucoma Compared with Healthy Subjects: A meta-analysis of the Literature.

PURPOSE: The aim of this meta-analysis of the literature is to provide a comprehensive analysis of the differences in Corvis ST dynamic corneal response (DCR) parameters between primary open-angle glaucoma (POAG) patients and healthy controls. METHODS: A quantitative meta-analysis was conducted on articles published before September 10, 2021 identified by searching PubMed, EMBASE, and Web of Science. Prospective studies comparing DCR Corvis ST parameter in high tension POAG and healthy controls were included. The random-effects model was conducted. Assessment of heterogeneity was based on the calculation of I2. Funnel plots evaluation and meta-regression were performed in case of detection of high heterogeneity. RESULTS: The selection process resulted in the inclusion of six articles. Pooled analysis revealed that POAG corneas respond to mechanical stimulus with a smaller concavity, showing lower deformation amplitude (DA) (CI95% -0.991 to -0.578; p < .001; I2 = 0%), higher highest concavity radius (HCR; confidence interval [CI]95% -0.01 to 0.34; p = .058; I2 = 6.7%), and lower peak distance (PD; CI95% -1.06 to -0.024; p = .040; I2 = 86.5%). They also show a slower loading phase, with lower highest concavity time (HCT; CI95% -0.39 to -0.02; p = .029; I2 = 3.3%) and lower applanation velocity-1 (CI95% -0.641 to -0.127; p = .003; I2 = 34.6%), and a faster restoration to the original form, shown by lower applanation time-2 (CI95% -1.123 to -0.544; p = .001; I2 = 44.8%) compared to healthy subjects. CONCLUSIONS: High tension POAG patients are characterized by stiffer corneas compared to healthy controls. These differences are valid also after removing the effect of age, corneal thickness, and intraocular pressure (IOP).

Camellens FIL622-1 IOL Implantation in the Ciliary Sulcus: Refractive Outcomes and Optimization of A-constant.

PURPOSE: To assess the refractive outcomes of patients who had sulcus implantation of the Camellens FIL622-1 intraocular lens (IOL) (Soleko) after posterior capsular rupture, and to optimize the A-constant suggested by the manufacturer. METHODS: This study included patients who underwent secondary Camellens FIL622-1 IOL implantation in the ciliary sulcus after complicated cataract surgery with posterior capsular rupture. IOL power was calculated by the SRK/T formula, using the recommended A-constant (118.8) for ciliary sulcus implantation. A new optimized A-constant was obtained and used to evaluate the refractive outcomes. The main outcome measures were mean prediction error (PE), median absolute error (MedAE), mean absolute error (MAE), and percentage of eyes with a PE within ±0.50, ±1.00, and ±2.00 diopters (D). RESULTS: Forty patients (40 eyes) were included in the study. The new optimized A-constant was 117.5, and the mean PE, MedAE, and MAE was -0.02 ± 0.73, 0.34, and 0.54, respectively. The percentage of eyes with a PE within ±0.50, ±1.00, and ±2.00 D was 65%, 87.5%, and 100%, respectively. CONCLUSIONS: The Camellens FIL622-1 IOL represents a valid option as sulcus implantation after posterior capsular rupture and it would guarantee the surgeon an on-label option with a more accurate biometric calculation, at the time of surgical implantation, with the new optimized A-constant. [J Refract Surg. 2022;38(12):806-811.].

Transepithelial Iontophoresis-Assisted Cross Linking for Progressive Keratoconus: Up to 7 Years of Follow Up.

PURPOSE: To report long-term clinical results of transepithelial cross-linking with iontophoresis (I-CXL) for progressive keratoconus (KC). Methods: Nineteen eyes of 19 patients treated with I-CXL for progressive keratoconus were included in this prospective clinical study. Preoperatively and in all available follow ups (6, 12, 24, 36, 48, 60, 72 and 84 months), the following parameters were measured. Corrected distance visual acuity (CDVA), spherical equivalent and cylinder refraction, corneal topography and aberrometry (Costruzione Strumenti Oftalmici (C.S.O.), Florence, Italy), Scheimpflug tomography (OCULUS Optikgeräte GmbH; Wetzlar, Germany). Definition of progression after I-CXL was 2/3 of the following criteria: increase of "A" value, increase of "B" value, decrease of minimal thickness evaluated with the ABCD progression display above 95% confidence interval for post-CXL population when compared to the scan 12 months post-op. Results: The mean follow-up time of included patients was 63 months (range 12 to 84 months, 5 patients reached 84 months). The general linear model showed no significant change over time in CDVA, Maximum Keratometry, Thinnest point, and A, B, C values of the Belin Progression Display (p > 0.05). Conversely, comatic and high order aberrations decreased significantly over time (both p =< 0.001). Five cases (26.31%) showed significant progression after a mean of 55 months (range 36-72) of follow up. Conclusion: Our study shows the ability of I-CXL to slow down KC progression in the majority of included patients, improving high order and comatic aberrations. A 26% progression rate was reported.

Corneal Cross-linking for Progressive Keratoconus in Patients Older Than 40 Years: Long-term Follow-up.

PURPOSE: To assess the long-term efficacy and safety of epithelium-off corneal cross-linking according to the standard (Dresden) protocol (S-CXL) in patients with progressive keratoconus older than 40 years. METHODS: Seventy-six eyes of 64 patients with a mean age of 46.4 ± 5.2 years were included. At baseline and after 6, 12, 24, 36, 48, 60, 72, 84, and more than 96 months (when available) after S-CXL, all patients were assessed with distance-corrected visual acuity (DCVA) and corneal topography and tomography with Pentacam HR (OCULUS Optikgeräte GmbH). A generalized linear model was used to compare the groups. Outcome measures were maximum keratometry, thinnest point, coma, spherical, and higher order aberrations, and ABC values. Fixed and random factors were age, gender, atopy, laterality, and group. RESULTS: The mean follow-up time was 62.1 ± 40.1 months (range: 12 to 144 months). The main outcome of the study was the evidence that S-CXL was able to safely stop the progression of keratoconus in all patients with none requiring repeat CXL. The generalized linear model analysis showed no significant change in DCVA over time (P = 1.000), but atopy was negatively associated with DCVA (P = .030, B = -0.69). The generalized linear model also showed that CXL was able to induce a significant flattening demonstrated as reduction of maximum keratometry (P = .001, B = -0.35) and A value (P =.001, B = -0.015) of the ABC display. Similarly, coma aberration was reduced over time (P = .006, B = -0.005). CONCLUSIONS: S-CXL was confirmed to be a safe and effective treatment for progressive keratoconus even after the age of 40 years, inducing a significant flattening of the cone. [J Refract Surg. 2021;37(5):338-342.].

Detection of postlaser vision correction ectasia with a new combined biomechanical index.

PURPOSE: To validate and evaluate the use of a new biomechanical index known as the Corvis biomechanical index-laser vision correction (CBI-LVC) as a method for separating stable post-LVC eyes from post-LVC eyes with ectasia. SETTING: 10 clinics from 9 countries. DESIGN: Retrospective, multicenter, clinical study. METHODS: The study was designed with 2 purposes: to develop the CBI-LVC, which combines dynamic corneal response (DCR) parameters provided by a high-speed dynamic Scheimpflug camera (CorVis ST; OCULUS Optikgeräte GmbH) and then to evaluate its ability to detect post-LVC ectasia. The CBI-LVC includes integrated inverse radius, applanation 1 (A1) velocity, A1 deflection amplitude, highest concavity and arclength, deformation amplitude ratio of 2 mm, and A1 arclength in millimeters. Logistic regression with Wald forward stepwise approach was used to identify the optimal combination of DCRs to create the CBI-LVC and then separate stable from LVC-induced ectasia. Eighty percentage of the database was used for training the software and 20% for validation. RESULTS: 736 eyes of 736 patients were included (685 stable LVC and 51 post-LVC ectasia). The receiver operating characteristic curve analysis showed an area under the curve of 0.991 when applying CBI-LVC in the validation dataset and 0.998 in the training dataset. A cutoff of 0.2 was able to separate stable LVC from ectasia with a sensitivity of 93.3% and a specificity of 97.8%. CONCLUSIONS: The CBI-LVC was highly sensitive and specific in distinguishing stable from ectatic post-LVC eyes. Using CBI-LVC in routine practice, along with topography and tomography, can aid the early diagnosis of post-LVC ectasia and allow intervention prior to visually compromising progression.

Management of an ophthalmology department during COVID-19 pandemic in Milan, Italy.

PURPOSE: Spreading from China, COVID-19 pandemic reached Italy, the first massively involved western nation. At the beginning of March, 2020 in Northern Italy a complete lockdown of activities was imposed. Access to all healthcare providers, was halted for patients with elective problems. We present the management experience of the Humanitas Clinical and Research Center Ophthalmology Department in Rozzano, Milan, Italy, during the lockdown. METHODS: Containment measures were taken to reduce viral transmission and identify infected patients. All planned visits were canceled but for those not deferrable. Social distancing was introduced reducing number of visits per hour. Minor surgery for progressive pathologies was continued. As the lockdown prolonged, we reorganized patient care. All canceled cases were evaluated by electronic medical records analysis and telephonic triage, to identify, recall, and visit patients at risk of vision loss. RESULTS: From March 9, to April 30, 2020 we performed a total of 930 visits and 612 exams. Some visits (n = 698) and exams (n = 160) were deemed as necessary for continuity of care and performed as planned. Among the remaining 1283 canceled appointments, after evaluation 144 visits and 32 instrumental exams were classified as urgent and rapidly rescheduled. Performed surgical activities were limited to corneal collagen cross linking (n = 39) and intravitreal injections (n = 91), compared to 34 and 94, respectively, in the same period of 2019. CONCLUSION: In-office activities deemed not deferrable were performed safely. The recall service was highly appreciated by all patients. No patient or staff member reported symptoms of COVID-19.

Evaluating keratoconus progression prior to crosslinking: maximum keratometry vs the ABCD grading system.

PURPOSE: To evaluate the correlation between changes in maximum keratometry (Kmax) and ABC values from the ABCD Progression Display (Pentacam) in progressive keratoconus (KC) and to evaluate whether the ABC changes were able to detect progression earlier than Kmax. SETTING: Humanitas Clinical and Research Center, Rozzano, Milan, Italy. DESIGN: Retrospective study. METHODS: Kmax, ABC values, and thinnest point (ThCT) were recorded at the day of corneal crosslinking (CXL) (T0) and previous follow-up (T-1). In patients without earlier progression in Kmax, follow-up examination (T-2) was used to determine whether any of the ABC parameters reached statistical significance for progression. RESULTS: Seventy-six eyes of 63 patients scheduled for CXL with documented progression (Kmax increase of >1.00 diopter) were included. There was a significant, albeit moderate, correlation between the change in Kmax between T0 and T-1 and the change in both A (ρ = 0.391) and B values (ρ = 0.339). There was no significant correlation between the change in Kmax between T0 and T-1 and the change in either C or ThCT. In patients with T-2 examinations, 16 (51.6%) of 31 patients showed a statistically significant change on the ABCD progression display that was not detected with Kmax. CONCLUSIONS: This study showed a significant, but moderate, correlation between the change in Kmax and the change in A and B values in progressive KC. Moreover, more than half of the cases showed documented progression earlier with the ABCD progression display than that detected by standard Kmax changes. This study suggests possible changes in progression criteria to allow for earlier intervention.

Corneal Cross-linking for Progressive Keratoconus: Up to 13 Years of Follow-up.

PURPOSE: To assess the long-term efficacy and safety of epithelium-off corneal cross-linking according to the Dresden protocol (S-CXL) in progressive keratoconus. METHODS: Patients treated with S-CXL from April 2006 to January 2010 at Humanitas Clinical and Research Center, Rozzano, Italy, who completed at least 10 years of follow-up were included. Corrected distance visual acuity (CDVA), refraction, and corneal topography and tomography with Pentacam (OCULUS Optikgeräte GmbH) were evaluated at baseline and 10+ years after the procedure. The definition of progression after S-CXL was two of the following three criteria: increase of "A" value, increase of "B" value, or decrease of minimum thickness evaluated with the ABCD progression display above 95% CI for the post-CXL population. RESULTS: Twenty-seven eyes of 22 patients were included. At a mean of 11 years of follow-up (maximum 13 years), S-CXL was able to maintain CDVA and induce significant regularization of the corneal surface as demonstrated by a significant decrease of the central keratoconus index (P = .035) and a decrease of anterior curvature ("A" value) starting from 2.54 ± 2.46, which reduced to 1.14 ± 1.60 (P = .005) at 10+ years of follow-up. Two of 27 eyes included showed significant progression after S-CXL (7.4%). CONCLUSIONS: S-CXL was confirmed to be a safe and effective treatment for progressive keratoconus with a failure rate of 7.4% at up to 13 years of follow-up. The authors suggest the use of a combined progression system that evaluates anterior and posterior curvature and with thickness map together with the knowledge of the noise level of the testing system. [J Refract Surg. 2020;36(12):838-843.].

Fate of endothelial cells after intrastromal implantation of Descemet's membrane-endothelial cell tissue.

In non-Descemet Stripping Automated Endothelial Keratoplasty (nDSAEK), the host DM and endothelium are not removed surgically before the introduction of the posterior lamellar graft; the result is that the patient has both the healthy donor endothelium and the diseased or residual host endothelium. Conversely, DSAEK tissues, that are inserted with inverted polarity (upside down), do not survive and the graft fails. While the mechanism of endothelial cell transplantation is clear, the fate of the endothelial cells retained between two stromal interfaces and their physiological role, if any, is not well understood. The aim of our study was therefore to evaluate the viability of a healthy endothelial-Descemet's membrane (EDM) graft after the insertion into a stromal pocket of a recipient donor cornea. Research corneas (n = 52) were divided into three groups: Group A, where an EDM (obtained from another cornea) with good endothelium was inserted in a stromal pocket endothelium side down; Group B, consisting of control corneas with a stromal pocket but without EDM insertion; and Group C, pre-stripped membranes resting on their stroma (not in a stromal pocket). The tissues were preserved in tissue culture medium for 21 days at 31 °C. Parameters including viability of endothelial cells, expression of tight junctions (ZO-1) and thickness were evaluated. After 21 days, all the membranes inserted within the stromal pocket of Group A survived, although an average endothelial cell loss of 30.1% (± 18.10) and a mortality of 10.2% (± 22.86) were recorded. Qualitative analysis using triple staining with Hoechst, ethidium homodimer and calcein AM confirmed the mortality. ZO-1 was expressed where the cells were present, showing good integrity of tight junctions. Group C showed an average endothelial cell loss of 1.9% (± 3.38), a mortality of 0.02% (± 0.07) and a higher expression of ZO-1. An EDM graft with endothelium facing downwards can survive in a stromal pocket for at least 3 weeks, with an overall cell mortality of 30%. Further studies are needed to evaluate the possible outcomes of the insertion of a healthy intrastromal EDMs with reverse polarity and in edematous corneas.

Iontophoresis CXL With and Without Epithelial Debridement Versus Standard CXL: 2-Year Clinical Results of a Prospective Clinical Study.

PURPOSE: To compare the 2-year follow-up outcomes of three groups of patients with keratoconus treated with transepithelial iontophoresis (I-CXL), iontophoresis with epithelial removal (I-SCXL), and standard epithelium-off (S-CXL) CXL for progressive keratoconus. METHODS: Sixty eyes of 60 patients treated with CXL for progressive keratoconus were included in this comparative, prospective clinical study. Twenty patients were included in each group (I-CXL, I-SCXL, and S-CXL). Corrected distance visual acuity (CDVA), refraction, corneal topography, Scheimpflug tomography, and aberrometry were assessed at baseline and at 1, 3, 6, 12, and 24 months of follow-up. To assess the long-term safety and efficacy of these treatments, the preoperative values were compared with the values at 24 months of follow-up. RESULTS: The main outcome of the study was the non-statistically significant difference between the three protocols in induced change in most of the parameters, including visual acuity (P = .665), topographic indexes (all P > .05), and maximum keratometry (P = .611) after 2 years of follow-up. There were no significant differences in the change in refractive error following CXL in all groups or between groups (all P > .05). Conversely, I-CXL induced significantly less corneal thinning (P = .0299 and .0121) and a significantly greater reduction of higher order aberrations and coma (all P < .0001) compared to S-CXL and I-SCXL. All protocols induced a significant increase in visual acuity (S-CXL P = .0004, I-SCXL P = .0045, and I-CXL P = .004). CONCLUSIONS: The 2-year results of this comparative, prospective clinical study demonstrate the efficacy and safety of I-CXL to treat progressive keratoconus and overcome the limitations of CXL with epithelial debridement. [J Refract Surg. 2019;35(3):184-190.].

Progression of Keratoconus in Patients While Awaiting Corneal Cross-linking: A Prospective Clinical Study.

PURPOSE: To assess topographical changes in patients with keratoconus while awaiting corneal cross-linking (CXL) treatment. METHODS: In this prospective, double-center, observational clinical study, patients with keratoconus were enrolled. Progression was defined as a change in the curvature within the cone area of at least 1.00 diopter (D) on tangential map and a thinning of 20 µm at the thinnest point after measurements taken at least 3 months apart. Morphological parameters were assessed at baseline (day of listing for CXL) and on the day of CXL treatment, including slit-lamp biomicroscopy, keratometry (maximum, minimum, and mean), and thinnest corneal thickness using corneal tomography (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany). RESULTS: One hundred four eyes of 104 patients were included. The waiting time was 84.8 ± 62.9 days. Twenty-five percent of patients showed evidence of progression while waiting for treatment. Patients who progressed while waiting for treatment were younger (22.2 ± 6.79 years) compared to those who did not show evidence of progression (25.4 ± 5.62 years) (P = .02). Stratification by age groups showed a significant worsening of maximum keratometry of 1.18 ± 1.37 D in patients younger than 18 years compared to those 18 to 26 years of age and those older than 26 years (P = .002 and .042, respectively). The multivariate model confirmed that the progression steepening of the maximum keratometry while waiting for treatment was associated with age (P = .028). CONCLUSIONS: The results suggest that stratification of waiting time according to the patient's age is required to reduce the risk of further progression of keratoconus. [J Refract Surg. 2018;34(3):177-180.].

Corneal Cross-Linking Window Absorption (CXL-WA) as an Adjuvant Therapy in the Management of Aspergillus niger Keratitis.

PURPOSE: To evaluate the effectiveness of corneal cross-linking window absorption (CXL-WA) as an adjuvant therapy for Aspergillus keratitis. METHODS: A 90-year-old male came to our clinic complaining of hyperemic conjunctivitis and progressive visual loss in the right eye. Slit-lamp examination showed keratic precipitates, severe corneal opacity, and stromal edema. Corneal scraping culture was positive for Aspergillus niger. Because the clinical condition did not sufficiently improve with antifungal therapy, the patient underwent CXL-WA as an adjuvant therapy. RESULTS: During the first week after treatment, the Tyndall effect, corneal edema, and signs of ocular inflammation progressively lessened. At the third postoperative month, the cornea was stable without signs of fungal keratitis. However, after this period, a descemetocele appeared in the cornea (2 × 2 mm in diameter), so the patient underwent a corneal penetrating keratoplasty. Histological evaluation of the removed corneal tissue revealed the presence of hyphae and fungal infection. CONCLUSIONS: We reported a case of in vivo CXL-WA used as an adjuvant therapy for deep stromal Aspergillus keratitis. CXL did not completely eradicate the fungal infection which caused perforation 4 months after treatment and it still cannot be considered a definitive solution to mycotic keratitis, which maintains a poor long-term prognosis.

Transepithelial Iontophoresis Versus Standard Corneal Collagen Cross-linking: 1-Year Results of a Prospective Clinical Study.

PURPOSE: To compare 1-year transepithelial corneal collagen cross-linking with iontophoresis (I-CXL) outcomes with standard CXL (S-CXL) epithelium-off for progressive keratoconus. METHODS: Forty eyes of 40 patients with progressive keratoconus were included in this comparative, prospective clinical study. Corrected distance visual acuity (CDVA), spherical equivalent, cylinder refraction, corneal topography, Scheimpflug tomography, aberrometry, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months of follow-up. RESULTS: Patients received either I-CXL (20 eyes) or S-CXL (20 eyes). Functional parameters (visual acuity and aberrometry) showed a significant improvement (P < .05) after 6 and 12 months of follow-up in both groups. In the I-CXL group, the CDVA showed a rapid recovery of vision after 3 months (P = .01) compared to baseline. Morphological parameters showed a significant reduction of maximum keratometry in the S-CXL group by -1.05 ± 1.51 diopters (D) after 12 months, whereas the I-CXL group curvature was stable (-0.31 ± 1.87 D). Minimum pachymetry values were stable even after 12 months of follow-up in the I-CXL group, whereas a significant corneal thinning 12 months following treatment was recorded in the S-CXL group (P < .001). None of the patients had continuous progression of keratoconus or had to repeat CXL procedures. Endothelial cell counts did not change significantly (P > .05). CONCLUSIONS: The 1-year outcomes suggest that I-CXL might be comparable to S-CXL in stabilizing the progression of the degenerative ectatic disease. Additionally, quicker improvement of functional parameters was reported in the I-CXL group. [J Refract Surg. 2016;32(10):672-678.].

Iontophoresis-Assisted Corneal Collagen Cross-Linking with Epithelial Debridement: Preliminary Results.

Purpose. To report the early outcomes of iontophoresis-assisted corneal collagen cross-linking procedure with epithelial debridement (I-SCXL). Methods. Twenty eyes of twenty patients with progressive keratoconus were included in this prospective clinical study. Best spectacle corrected visual acuity (BSCVA), sphere and cylinder refraction, corneal topography, Scheimpflug tomography, aberrometry, anterior segment optical coherence tomography (AS-OCT), and endothelial cell count were assessed at baseline and at 1, 3, and 6 months of follow-up. The parameters considered to establish keratoconus progression were always proven with differential maps as change in curvature in the cone area of at least 1 diopter obtained with an instantaneous map. Results. Functional parameters showed a significant improvement (p < 0.05) of BSCVA after 3 and 6 months of follow-up. Morphological parameters indicated stabilization of the corneal ectasia during the follow-up; however, a positive trend was noted with a mean flattening of 1.73 D. Minimum pachymetry values showed thinning that remained constant after the treatment. The demarcation line was clearly visible in all patients, reaching a depth of 308.2 ± 37.74 µm. None of the patients had continuous progression of keratoconus or had to repeat cross-linking procedures. Endothelial cell counts did not change significantly (p > 0.05). Conclusion. The early results indicate that the I-SCXL may be able to reduce the treatment time and improve the riboflavin diffusion.

Transepithelial iontophoresis corneal collagen cross-linking for progressive keratoconus: initial clinical outcomes.

PURPOSE: To report initial clinical results of transepithelial corneal collagen cross-linking with iontophoresis (I-CXL). METHODS: Twenty eyes of 20 patients diagnosed as having progressive keratoconus who underwent I-CXL were included in this prospective non-randomized clinical study. Corrected distance visual acuity (CDVA), spherical equivalent and cylinder refraction, various corneal topography and Scheimpflug tomography parameters, aberrometry, anterior segment optical coherence tomography, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months postoperatively. RESULTS: CDVA improved significantly at 3, 6, and 12 months postoperatively (logMAR difference of -0.07 ± 0.01, -0.09 ± 0.03, and -0.12 ± 0.06, respectively; P < .05). Aberrometry remained stable during follow-up and a trend toward improvement was noted. All topographic parameters (including maximum keratometry) were stable during the follow-up, but exhibited a positive non-significant trend toward improvement. Minimum corneal thickness values were stable for up to 12 months postoperatively. None of the patients showed a progression of keratoconus. Endothelial cell counts did not change significantly (P > .05). CONCLUSIONS: Preliminary results up to 1 year postoperatively indicate the efficacy of I-CXL in stabilizing the progression of this degenerative disease combined with significant improvement of CDVA. I-CXL, which spares the corneal epithelium, has the potential to become a valid alternative for halting the progression of keratoconus while reducing postoperative patient pain, risk of infection, and treatment time in select patients; however, the relative efficacy of this technique compared to standard epithelium-off techniques remains to be determined.

Biological parameters determining the clinical outcome of autologous cultures of limbal stem cells.

AIM: Limbal cultures restore the corneal epithelium in patients with ocular burns. We investigated the biological parameters instrumental for their clinical success. METHODS: We report a long-term multicenter prospective study on 152 patients carrying corneal destruction due to severe ocular burns, treated with autologous limbal cells cultured on fibrin and clinical-grade 3T3-J2 feeder cells. Clinical results were statistically evaluated both by parametric and nonparametric methods. RESULTS: Clinical outcomes were scored as full success, partial success and failure in 66.05, 19.14 and 14.81% of eyes, respectively. The total number of clonogenic cells, colony size, growth rate and presence of conjunctival cells could not predict clinical results. Instead, the clinical data provided conclusive evidence that graft quality and likelihood of a successful outcome rely on an accurate evaluation of the number of stem cells detected before transplantation as holoclones expressing high levels of the p63 transcription factor. No adverse effects related to the feeder layer have been observed and the regenerated epithelium was completely devoid of any 3T3-J2 contamination. CONCLUSION: Cultures of limbal stem cells can be safely used to successfully treat massive destruction of the human cornea. We emphasize the importance of a discipline for defining the suitability and the quality of cultured epithelial grafts, which are relevant to the future clinical use of any cultured cell type.