Long-term evaluation of corneal sub-basal nerve recovery after photorefractive keratectomy and influence of pars plana vitrectomy.

The corneal sub-basal nerve (SBN) plexus is destroyed during photorefractive keratectomy (PRK) and its recovery is still a matter of debate. In vivo confocal microscopy (IVCM) was used to evaluate SBN plexus in 23 patients at a distance of 10-25 years (mean 15.6 years) from myopic PRK. Because 8 out of the 23 PRK patients underwent pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment, IVCM was also performed on those patients 6 months after PPV. Thirteen patients matched for age and myopia served as controls (non-PRK). SBN plexus was markedly reduced after PRK compared with non-PRK eyes and showed a slow, continuous but incomplete recovery up to the end of our follow-up (range 10-25 years). PRK and non-PRK eyes showed a marked reduction in SBN density 6 months after PPV, thus demonstrating a detrimental effect exerted by PPV on SBN plexus.

COMPLEX RETINAL DETACHMENT IN PHAKIC PATIENTS: Previtrectomy Phacoemulsification Versus Combined Phacovitrectomy.

PURPOSE: To assess the impact of phacoemulsification performed one week before pars plana vitrectomy versus combined phacovitrectomy on postoperative anterior segment status and final functional and anatomical outcomes in phakic patients affected by complex rhegmatogenous retinal detachment. METHODS: The authors retrospectively reviewed the records of 59 phakic patients affected by complex rhegmatogenous retinal detachment. Twenty-nine patients underwent cataract surgery 7 days before vitrectomy (preemptive cataract surgery-Group 1), whereas 30 patients underwent combined phacovitrectomy (Group 2). Preoperative, intraoperative, early- and late-postoperative outcomes were measured and compared. RESULTS: Numbers of previous retinal surgical procedures, nuclear sclerosis grade, proliferative vitreoretinopathy grade, eyes with inferior breaks, surgical time, and ratio of silicone oil/gas tamponade were all similar between the two groups. After surgery, there was less extension of posterior synechia in Group 1. There was no significant difference in fibrin, number of patients with posterior synechia, final intraocular pressure, retinal redetachment rate, final retinal status, or final best-corrected visual acuity. CONCLUSION: Preemptive cataract surgery was associated with less extensive postoperative posterior synechia, however, its final functional and anatomical outcomes were not significantly different from those of phacovitrectomy. Both approaches were efficacious.

In vivo confocal microscopy: qualitative investigation of the conjunctival and corneal surface in open angle glaucomatous patients undergoing the XEN-Gel implant, trabeculectomy or medical therapy.

PURPOSE: Assessing the quality of the ocular surface by in vivo scanning laser confocal microscopy (IVCM) in primary open angle glaucoma (POAG) patients treated by Xen 45 Gel Stent, medical therapy and trabeculectomy. METHODS: Retrospective, single-center, single-masked, comparative study including 60 eyes of 30 patients (mean age 61.16 ± 10 years) affected by POAG. Eyes were divided into 3 groups: Group 1 eyes underwent the Xen 45 Gel Stent procedure, Group 2 eyes were under medical therapy, Group 3 eyes were surgically treated by trabeculectomy. All patients underwent HRT II IVCM analysis of cornea, limbus, conjunctiva, sub-tenionian space and sclera. RESULTS: The Xen 45 Gel stent, if properly positioned in the sub-conjunctival space preserves goblet cells and limits ocular surface inflammation. Regular corneal epithelial cells with micro-cysts, and normo-reflective sub-epithelial nerve plexus are documented by IVCM. In sub Tenon's implants an alternative lamellar intra-scleral filtration is detectable. Combined surgical procedures show a noticeable number of inflammatory cells with rare micro-cysts. Post-trabeculectomy inflammatory reaction is more evident than Xen 45 Gel Stent associated surgical procedures, but less than medical therapy where a conspicuous presence of Langerhans cells, peri-neural infiltrates, marked loss of goblet cells and fibrosis is visible. CONCLUSION: Ocular surface inflammation was more notable in topical therapy than after trabeculectomy, which itself causes more inflammation than XEN Gel stents.

Confocal microscopy identification of keratoconus associated with posterior polymorphous corneal dystrophy.

We present a case of keratoconus in which the association with posterior polymorphous corneal dystrophy was established by confocal microscopy. Confocal microscopy enable us to assess the differential diagnosis between posterior corneal dystrophies, essential for a prognosis and therapeutic decision.

Corneal Collagen Cross-Linking With Riboflavin and Ultraviolet A Light for Pediatric Keratoconus: Ten-Year Results.

PURPOSE: To assess the 10-year follow-up efficacy and safety of riboflavin ultraviolet A-induced cross-linking (CXL) in a population of pediatric patients aged 18 years and younger with progressive keratoconus (KC). METHODS: The prospective longitudinal cohort study included 62 eyes of 47 keratoconic patients undergoing epithelium-off CXL who completed 10-year follow-up. The surgical procedure was performed in all patients according to the Siena (Dresden modified) protocol. Evaluation included uncorrected distance visual acuity, corrected distance visual acuity, Scheimpflug corneal tomography, and optical coherence tomography demarcation line measurement. Follow-up measurements taken up to 10 years after treatment were compared with baseline values, and statistical analysis was performed using a 2-tailed paired sample Student t test. RESULTS: Uncorrected distance visual acuity and corrected distance visual acuity improved from 0.45 to 0.23 logarithm of the minimum angle resolution (P = 0.0001) and from 0.14 to 0.1 logarithm of the minimum angle resolution (P = 0.019). KC stability was recorded after 10 years of follow-up in nearly 80% of the patients. The overall 10-year follow-up progression rate was 24% including 13 eyes of 9 patients with Kmax progression over 1 diopter and 2 eyes of 2 patients who underwent corneal grafting. CONCLUSIONS: The study demonstrates the ability of CXL to slow down KC progression in pediatric patients, improving functional performance. Long-term stability may be correlated with CXL-induced delay in corneal collagen turnover and with spontaneous age-related KC stabilization. A 24% regression rate could be contemplated in the patients who were aged 15 years and younger at the time of inclusion in the treatment protocol.

Publisher Correction: TGF-ß concentrations and activity are down-regulated in the aqueous humor of patients with neovascular age-related macular degeneration.

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TGF-ß concentrations and activity are down-regulated in the aqueous humor of patients with neovascular age-related macular degeneration.

Controversy still exists regarding the role of the TGF-ß in neovascular age-related macular degeneration (nAMD), a major cause of severe visual loss in the elderly in developed countries. Here, we measured the concentrations of active TGF-ß1, TGF-ß2, and TGF-ß3 by ELISA in the aqueous humor of 20 patients affected by nAMD, who received 3 consecutive monthly intravitreal injections of anti-VEGF-A antibody. Samples were collected at baseline (before the first injection), month 1 (before the second injection), and month 2 (before the third injection). The same samples were used in a luciferase-based reporter assay to test the TGF-ß pathway activation. Active TGF-ß1 concentrations in the aqueous humor were below the minimum detectable dose. Active TGF-ß2 concentrations were significantly lower at baseline and at month 1, compared to controls. No significant differences in active TGF-ß3 concentration were found among the sample groups. Moreover, TGF-ß pathway activation was significantly lower at baseline compared to controls. Our data corroborate an anti-angiogenic role for TGF-ß2 in nAMD. This should be considered from the perspective of a therapy using TGF-ß inhibitors.

Riboflavin and ultraviolet A collagen crosslinking: in vivo thermographic analysis of the corneal surface.

PURPOSE: To assess the possible thermal damage to the cornea during combined riboflavin and ultraviolet-A crosslinking using in vivo surface thermographic analysis. SETTING: Department of Oto-Neuro-Ophthalmological Surgical Sciences, Eye Clinic, University of Florence, Florence, Italy. METHODS: Collagen crosslinking was performed on a day-surgery basis under aseptic conditions with traditional techniques. During the procedure, temperature measurements on the corneal surface were taken using an infrared thermocamera. The temperature values were detected in the area directly exposed to light irradiation, selecting it in the acquired thermographic image. Because the aim of the study was to consider the thermal damage that may be induced during the procedure, the maximum temperature value detected in the area studied was recorded and considered for successive analysis. RESULTS: Infrared thermocamera measurements of the corneal surface during crosslinking treatment showed that the temperature was constant during the entire procedure and remains under the threshold of thermal injury to corneal collagen. CONCLUSION: Corneal collagen crosslinking was a safe procedure that did not cause thermal injury to the corneal surface.

Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans.

PURPOSE: To assess ultrastructural stromal modifications after riboflavin-UVA-induced cross-linking of corneal collagen in patients with progressive keratoconus. METHODS: This was a second-phase prospective nonrandomized open study in 10 patients with progressive keratoconus treated by riboflavin-UVA-induced cross-linking of corneal collagen and assessed by means of Heidelberg Retinal Tomograph II Rostock Corneal Module (HRT II-RCM) in vivo confocal microscopy. The eye in the worst clinical condition was treated for each patient. Treatment under topical anesthesia included corneal deepithelization (9-mm diameter) and instillation of 0.1% riboflavin phosphate-20% dextran T 500 solution at 5 minutes before UVA irradiation and every 5 minutes for a total of 30 minutes. UVA irradiation was 7 mm in diameter. Patients were assessed by HRT II-RCM confocal microscopy in vivo at 1, 3, and 6 months after treatment. RESULTS: Rarefaction of keratocytes in the anterior and intermediate stroma, associated with stromal edema, was observed immediately after treatment. The observation at 3 months after the operation detected keratocyte repopulation in the central treated area, whereas the edema had disappeared. Cell density increased progressively over the postoperative period. At approximately 6 months, keratocyte repopulation was complete, accompanied by increased density of stromal fibers. No endothelial damage was observed at any time. CONCLUSIONS: Reduction in anterior and intermediate stromal keratocytes followed by gradual repopulation has been confirmed directly in vivo in humans by HRT II-RCM confocal microscopy after riboflavin-UVA-induced corneal collagen cross-linking.

Accelerated 15 mW pulsed-light crosslinking to treat progressive keratoconus: Two-year clinical results.

PURPOSE: To assess the clinical and microstructural results of accelerated 15 mW pulsed-light corneal crosslinking (CXL) to treat progressive keratoconus. SETTING: Siena Crosslinking Center, Siena, Italy. DESIGN: Prospective case series. METHODS: After epithelium removal (with Epi-Clear) and 10 minutes stromal soaking with riboflavin 0.1% hydroxypropyl methylcellulose solution, all eyes had 15 mW/cm2 pulsed-light epithelium-off accelerated CXL for 6 minutes of ultraviolet-A (UVA) irradiation (1 second on/1 second off), maintaining a total UVA exposure of 12 minutes at a fluence of 5.4 J/cm2. The 2-year follow-up examination included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, Scheimpflug tomography, in vivo confocal microscopy (IVCM), and spectral-domain optical coherence tomography (SD-OCT). RESULTS: The study comprised 132 eyes of 96 patients (mean age 23.7 years ± 4.3 [SD]) with stage II keratoconus. The change in UDVA and CDVA was statistically significant, from 0.51 ± 0.106 logarithm of the minimum angle of resolution (logMAR) at baseline to 0.309 ± 0.074 logMAR (P = .0001) and 0.271 ± 0.144 logMAR at baseline to 0.135 ± 0.100 logMAR (P = .0023), respectively. Coma values measured by Scheimpflug analysis showed a statistically significant improvement beginning with the first postoperative month (P = .0004). The IVCM scans documented basal epithelial healing occurring 72 hours after treatment associated with the presence of subepithelial nerves. The SD-OCT scans performed in the central 6.0 mm of corneal diameter documented a demarcation line at a mean depth of 280 ± 32 µm. CONCLUSION: The 15 mW/cm2 pulsed-light epithelium-off accelerated CXL was effective and safe, stabilizing keratoconus progression through 2 years of follow-up.

HTRA1 and TGF-ß1 Concentrations in the Aqueous Humor of Patients With Neovascular Age-Related Macular Degeneration.

Purpose: The purpose of this study was to evaluate the expression of high-temperature requirement A serine peptidase 1 (HTRA1), TGF-ß1, bone morphogenetic protein 4 (BMP4), growth differentiation factor 6 (GDF6), and VEGFA proteins in the aqueous humor of patients with naïve choroidal neovascularization (nCNV) secondary to AMD. Methods: We measured by ELISA the concentrations of HTRA1, TGF-ß1, BMP4, GDF6, and VEGFA in the aqueous humor of 23 patients affected by nCNV who received three consecutive monthly intravitreal injections of 0.5 mg ranibizumab. Samples were collected at baseline (before the first injection), month 1 (before the second injection), and month 2 (before the third injection). Twenty-three age-matched cataract patients served as controls. Results: Bone morphogenetic protein 4 and GDF6 were not detectable in any samples. Baseline HTRA1 was higher than controls (P < 0.0001) and higher than both the month 1 (P < 0.0001) and the month 2 (P < 0.0001) values. Baseline VEGFA was higher than controls (P < 0.0001), not different from month 1 value (P = 0.0821), but higher than month 2 value (P < 0.0001). Baseline TGF-ß1 was higher than controls (P = 0.0015) and not different from month 1 (P = 0.129) and month 2 values (P = 0.5529). No correlation was found in naïve patients between concentrations of HTRA1 and TGF-ß1, HTRA 1 and VEGFA, or TGF-ß1 and VEGFA. Conclusions: In nCNV patients, HTRA1 and TGF-ß1 were significantly higher compared to controls. After treatment, TGF-ß1 was persistently elevated, while HTRA1 returned to control levels, suggesting the involvement of TGF-ß1 and HTRA1 in neovascular AMD and a VEGFA-independent role for TGF-ß1.

Parasurgical therapy for keratoconus by riboflavin-ultraviolet type A rays induced cross-linking of corneal collagen: preliminary refractive results in an Italian study.

PURPOSE: To assess the effectiveness of riboflavin-ultraviolet type A rays induced cross-linking of corneal collagen in reducing progression of keratoconus and in improving visual acuity in patients with progressive keratoconus. SETTING: Department of Ophthalmology, Siena University, Siena, Italy. METHODS: This was a second-phase prospective nonrandomized open study. Starting in September 2004, 10 eyes of 10 patients (mean age 31.4 years) with bilateral keratoconus were treated by combined riboflavin-ultraviolet type A rays (UVA) collagen cross-linking. Radiant energy was 3 mW/cm2 or 5.4 joule/cm2 for a 30-minute exposure at 1 cm from the corneal apex. A complete ophthalmologic examination (uncorrected visual acuity [UCVA], sphere spectacles corrected visual acuity (SSCVA), best spectacle-corrected visual acuity [BSCVA]) was performed. Patients had corneal computerized topographic examination, linear scan optical tomography, endothelial cell count, ultrasound pachometry, intraocular pressure (IOP) evaluation, and HRT II system confocal microscopy at 1, 2, 3, and 6 months. After treatment, eyes were medicated and dressed with a soft contact lens. RESULTS: Comparative preoperative and postoperative results showed increases of 3.6 lines for UCVA (P = .0000112), 1.85 lines for SSCVA (P = .00065), and 1.66 lines for BSCVA (P = .00071). Topographic analysis showed a mean K reduction of 2.1 +/- 0.13 diopters (D) in the central 3.0 mm. Statistical analysis of IOP and endothelial cell count did not show significant differences. Topo-aberrometric analysis findings of corneal symmetry showed a trend toward increasing corneal symmetry with a major reduction in asymmetry between vertical hemimeridians. CONCLUSIONS: Refractive results showed a reduction of about 2.5 D in the mean spherical equivalent, topographically confirmed by the reduction in mean K. Results of surface aberrometric analysis showed improvement in morphologic symmetry with a significant reduction in comatic aberrations.

Accelerated Corneal Collagen Cross-Linking Using Topography-Guided UV-A Energy Emission: Preliminary Clinical and Morphological Outcomes.

Purpose. To assess the clinical and morphological outcomes of topography-guided accelerated corneal cross-linking. Design. Retrospective case series. Methods. 21 eyes of 20 patients with progressive keratoconus were enrolled. All patients underwent accelerated cross-linking using an ultraviolet-A (UVA) exposure with an energy release varying from 7.2 J/cm2 up to 15 J/cm2, according to the topographic corneal curvature. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, topography, in vivo confocal microscopy (IVCM), and anterior segment optic coherence tomography (AS-OCT) were evaluated preoperatively and at the 1, 3, 6, and 12 months postoperatively. Results. 12 months after surgery UDVA and CDVA did not significantly vary from preoperative values. The average topographic astigmatism decreased from -4.61 ± 0.74 diopters (D) to -3.20 ± 0.81 D and coma aberration improved from 0.95 ± 0.03 µm to 0.88 ± 0.04 µm after surgery. AS-OCT and IVCM documented differential effects on the treated areas using different energies doses. The depths of demarcation line and keratocyte apoptosis were assessed. Conclusions. Preliminary results show correspondence between the energy dose applied and the microstructural stromal changes induced by the cross-linking at various depths in different areas of treated cornea. One year after surgery a significant reduction in the topographic astigmatism and comatic aberration was detected. None of the patients developed significant complications.

Phenotypic Spectrum of Granular Corneal Dystrophy Type II in Two Italian Families Presenting an Unusual Granular Corneal Dystrophy Type I Clinical Appearance.

Clinical, instrumental, and genetic findings are reported in Italian families with Type II Granular Corneal Dystrophies (GCD2) presenting an initial unusual presentation of a Granular Corneal Dystrophy Type I (GCD1) phenotypic spectrum in female descendants. Slit-lamp examinations showed the typical phenotypic features of GCD2 in both mothers and a phenotypic appearance of GCD1 in both daughters. Despite the different phenotypic onset, the genetic diagnostic testing revealed the presence of a mutation in the TGFB-I gene, typical of GCD2 in both cases, excluding GCD1. Patients who were clinically suspected of corneal dystrophy need a genetic confirmatory testing for certain diagnosis. Genetic test may help to find the specific mutation distinguishing between different phenotypic spectra with relative diagnostic and prognostic implications. The study demonstrates that the phenotypic spectrum of genetically confirmed granular corneal dystrophies in patients may change over time. Since the R124H mutation has also been described in clinically asymptomatic individuals prior to LASIK, who then develop dramatic deposition, suggesting that this particular mutation and phenotype may be sensitive to, precipitated, or modified by central cornea trauma, a careful familial anamnesis excluding cornel dystrophies and specific preoperative genetic test are recommended prior to LASIK.

Corneal Complications During and After Vitrectomy for Retinal Detachment in Photorefractive Keratectomy Treated Eyes.

To evaluate the occurrence of late-onset corneal haze (LOCH) after vitrectomy for rhegmatogenous retinal detachment (RRD) in photorefractive keratectomy (PRK)-treated eyes. This observational cohort study comprised 13 eyes of 13 patients who underwent vitrectomy for RRD and who had been subjected to PRK years earlier. The occurrence of LOCH was evaluated together with all the preoperative, intraoperative, and postoperative factors that could affect final corneal status. LOCH developed in 2 eyes. Both patients had undergone PRK for high myopia--one 3 years and the other 9 years prior to RRD. Both patients presented with RRD due to giant retinal tear and were subjected to scleral buckle, 20-gauge vitrectomy, and silicone oil tamponade. Three months after vitrectomy and 1 month after silicone oil removal they both developed LOCH. During vitreoretinal surgery neither of the 2 patients needed mechanical epithelial debridement. Intraoperative epithelial debridement was performed in 2 of the other patients of the series, who had undergone previous PRK for high myopia and had clear corneas at presentation; in 1 of them this manoeuvre hampered intraoperative visualization. Follow-up after retinal detachment surgery ranged from 6 to 156 months (mean, 37.5 months). Subepithelial corneal scarring may be reactivated many years after PRK. In our series this happened after vitrectomy.

Implante Ex-PRESS mediante la técnica de Richard Hoffman / Ex-PRESS implantation by Richard Hoffman's technique

La cirugía filtrante es una opción de tratamiento encaminada a disminuir la presión intraocular una vez que no hay respuesta a las alternativas no quirúrgicas. En los últimos años ha experimentado una evolución sorprendente. Aparecen nuevos dispositivos que buscan obtener un control tensional con las mínimas complicaciones; entre estos, el implante Ex-PRESS ha demostrado una efectividad similar a la trabeculectomía, mientras que la variante técnica para su implantación, descrita por Richard Hoffmann, posibilita excelentes resultados con menos dificultades. Se presenta un paciente masculino de 51 años de edad, de raza blanca, con antecedente de glaucoma, con agudeza visual mejor corregida de 100 VAR y presión intraocular de 32 mmHg. Se realizó implante de dispositivo Ex-PRESS (modelo P-50) mediante la técnica modificada de Richard Hoffmann, asociada al uso de mitomicina C al 0,2 por ciento en el transoperatorio. A los dos años se lograron tensiones oculares de 17 mmHg y agudeza visual mejor corregida de 100 VAR(AU)

Filtration surgery is a therapeutic option aimed at reducing intraocular pressure when there is no response to non-surgical alternatives. Filtration surgery has developed remarkably in recent years. New devices have emerged geared to achieving pressure control with minimum complications. Among them, Ex-PRESS implantation has shown to be as effective as trabeculectomy, and the technique described by Richard Hoffman provides excellent results with fewer difficulties. A case is presented of a male white 51-year-old patient with a history of glaucoma, best corrected visual acuity 100 VAR, and intraocular pressure 32 mmHg. Implantation was performed of an Ex-PRESS (model P-50) device by modified Richard Hoffman's technique associated to 0.2 percent mitomycin C in the perioperative period. Two years after surgery, ocular tensions of 17 mmHg and a best corrected visual acuity of 100 VAR had been achieved(AU)

Late corneal scarring after retinal detachment surgery 42 months after photorefractive keratectomy.

A 42-year-old man had uneventful bilateral nonsimultaneous photorefractive keratectomy (PRK) for severe myopia. Thirty-nine months after the procedure, the patient presented with a retinal detachment (RD) in the right eye. Cerclage, vitrectomy, endolaser, and intravitreal silicone oil tamponade were performed, and the RD was successfully repaired. Three months after vitrectomy and 42 months after PRK, the patient complained of visual impairment in the right eye and photophobia. On slitlamp examination, marked reticular scarring of the central anterior cornea was observed. The occurrence of late-onset corneal haze highlights the need for special attention to patients who have vitrectomy after PRK.

Preliminary results of cataract extraction with implantation of a single-piece AcrySof intraocular lens.

PURPOSE: To evaluate the intraoperative and postoperative performance of the single-piece AcrySof SA30AL intraocular lens (IOL) in a series of patients after cataract surgery and IOL implantation. SETTING: Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy. METHODS: In this prospective study, 20 patients who had phacoemulsification and implantation of a single-piece AcrySof SA30AL lens from March to April 2000 were evaluated. Assessed were control of IOL folding, ease of IOL implantation, IOL centration, intraoperative and postoperative complications, visual acuity, and anterior (ACO) and posterior (PCO) capsule opacification. RESULTS: In all cases, the IOL was easily folded, inserted, and unfolded. It remained well centered in the capsular bag, and there were no intraoperative or postoperative complications. The best corrected visual acuity after surgery was 20/40 or better in all patients. No eye developed ACO or phimosis. One eye had a well-demarcated, oval area of lens epithelial cell proliferation on the posterior capsule that did not impair visual acuity. CONCLUSIONS: Initial results indicate that the single-piece AcrySof SA30AL IOL has good biocompatibility, haptic flexibility and resistance, and stability in the capsular bag. The incidence of PCO in 1 eye could have been the result of several factors and requires further evaluation. An area of future study is the wide haptic of the lens, which may create a path for cells to proliferate as they travel from the equatorial capsule.

Transepithelial corneal collagen crosslinking for progressive keratoconus: 24-month clinical results.

PURPOSE: To assess the clinical results of transepithelial collagen crosslinking (CXL) in patients 26 years and younger with progressive keratoconus suitable for epithelium-off (epi-off) CXL. SETTING: Department of Ophthalmology, Siena University Hospital, Siena, Italy. DESIGN: Prospective case series. METHODS: The study included 26 eyes (26 patients) treated by transepithelial (epithelium-on) CXL. The mean age was 22 years (range 11 to 26 years) (10 younger than 18 years; 16 between 19 years and 26 years). Preoperative and postoperative examinations included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, simulated maximum keratometry (K), coma and spherical aberration, and corneal optical coherence tomography optical pachymetry. The solution for transepithelial CXL (Ricrolin TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with the Caporossi Baiocchi Mazzotta X Linker Vega at 3 mW/cm(2). RESULTS: After relative improvement in the first 3 to 6 months, the UDVA and CDVA gradually returned to baseline preoperative values. After 12 months of stability, the simulated maximum K value worsened at 24 months. Coma aberration showed no statistically significant change. Spherical aberration increased at 24 months. Pachymetry showed a progressive, statistically significant decrease at 24 months. Fifty percent of pediatric patients were retreated with epi-off CXL due to significant deterioration of all parameters after 12 months of follow-up. CONCLUSIONS: Functional results after transepithelial CXL showed keratoconus instability, in particular in pediatric patients 18 years old and younger; there was also functional regression in patients between 19 years and 26 years old after 24 months of follow-up. mentioned.