Localized Refractive Changes Induced by Symmetric and Progressive Asymmetric Intracorneal Ring Segments Assessed with a 3D Finite-Element Model.

To build a representative 3D finite element model (FEM) for intracorneal ring segment (ICRS) implantation and to investigate localized optical changes induced by different ICRS geometries, a hyperelastic shell FEM was developed to compare the effect of symmetric and progressive asymmetric ICRS designs in a generic healthy and asymmetric keratoconic (KC) cornea. The resulting deformed geometry was assessed in terms of average curvature via a biconic fit, sagittal curvature (K), and optical aberrations via Zernike polynomials. The sagittal curvature map showed a locally restricted flattening interior to the ring (Kmax -11 to -25 dpt) and, in the KC cornea, an additional local steepening on the opposite half of the cornea (Kmax up to +1.9 dpt). Considering the optical aberrations present in the model of the KC cornea, the progressive ICRS corrected vertical coma (-3.42 vs. -3.13 µm); horizontal coma (-0.67 vs. 0.36 µm); and defocus (2.90 vs. 2.75 µm), oblique trefoil (-0.54 vs. -0.08 µm), and oblique secondary astigmatism (0.48 vs. -0.09 µm) aberrations stronger than the symmetric ICRS. Customized ICRS designs inspired by the underlying KC phenotype have the potential to achieve more tailored refractive corrections, particularly in asymmetric keratoconus patterns.

New ZNF469 Mutations in Spanish Siblings With Brittle Cornea Syndrome.

PURPOSE: The aim of this study was to describe the clinical, tomographic, and genetic findings of 2 Spanish siblings with brittle cornea syndrome and report a new mutation of gene ZNF469 implicated in the development of this disorder. METHODS: In this study, 2 male siblings who had been diagnosed with brittle cornea syndrome underwent ophthalmologic and genetic assessment. RESULTS: A novel homozygous deletion c.2972del, p.(Pro991Hisfs62) in the ZNF469 gene was identified in a Spanish family. CONCLUSIONS: This is the first report of a ZNF469 mutation in a Spanish family causing brittle cornea syndrome. The discovery of this new mutation amplifies the spectrum of ZNF469 variants implicated in this syndrome.

Pars plana vitrectomy and therapeutic keratoplasty in endophthalmitis and infectious keratitis.

PURPOSE: To describe the anatomical and functional outcomes of patients with infectious keratitis (IK) and secondary endophthalmitis who underwent penetrating keratoplasty (PK) after pars plana vitrectomy (PPV) assisted by temporary keratoprosthesis (TKP). METHODS: An observational retrospective case series was performed. Data were collected from January 2013 to July 2020. Patients over 18 years old with a clinical and microbiological diagnosis of IK, and clinical, ultrasonographic, and or microbiological diagnosis of endophthalmitis were included. Anatomical success was defined as infection resolution with preservation of the ocular globe integrity. No change or improvement of best-corrected visual acuity (VA) at the last follow-up was considered as a functional success. RESULTS: A total of 32 eyes of 32 patients were analyzed. The anatomic success was obtained in 87.5% eyes in which the infection was eradicated. The 63% patients maintained or improved their best-corrected VA, 37.5% ended up with hand motion VA. CONCLUSIONS: Our results suggest that PPV assisted by TKP followed by PKP can be a good approach for treating patients with endophthalmitis secondary to IK while allowing further visual improvement after an optical PK. Further prospective studies need to be done to evaluate final visual rehabilitation of these patients.

Analysis of visual and refractive results after wedge resection for high astigmatism after penetrating keratoplasty in keratoconus.

PURPOSE: To analyze visual and refractive results after wedge resection to correct high astigmatism after penetrating keratoplasty (PK) for keratoconus. SETTING: Cornea Unit of the Centro de Oftalmología Barraquer Barcelona, Spain. DESIGN: A retrospective quasi-experimental, before and after study. METHODS: Patients who developed high astigmatism or ectasia in the graft-host junction after PK were treated with wedge resection. The following variables were studied before the surgery, 1-year after and at the final visit: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive and topographic astigmatism and spherical equivalent. Vectorial analysis of the astigmatism changes was performed. RESULTS: Fifty-one eyes were included with a mean follow-up of 4.19 ± 3.09 years. Mean refractive astigmatism was 11.47 ± 3.57 diopters (D) pre-operatively and 4.79 ± 3.32 D at the final follow-up (p < 0.001). The mean centroid changed from 2.65 ± 11.82 D at 23 degrees preoperatively to 0.35 ± 5.86 D at 127 degrees postoperatively. Concerning spherical equivalent, the mean preoperative value was -3.10 ± 4.15 D and the mean postoperative value was -1.55 ± 3.41 D (p = 0.002). Mean pre-operative and final follow-up UDVA were 1.25 ± 0.27 and 0.84 ± 0.50 (p < 0.001). Mean Pre-op and final follow-up CDVA were 0.27 ± 0.19 and 0.24 ± 0.24. CONCLUSIONS: Wedge resection is a useful surgical procedure to correct high astigmatism. It is a safe technique with moderate efficacy and may be considered as initial procedure of choice in high astigmatism due to long-term ectasia in the graft-host junction after PK for keratoconus.

Bilateral Corneal Ectasia 3 Years After Small Incision Lenticule Extraction in a Borderline Case.

PURPOSE: The purpose of this study was to report a case of bilateral ectasia 3 years after small incision lenticule extraction (SMILE) in a patient with normal preoperative topography of the right eye and abnormal topography of the left eye. METHODS: This study was a case report. RESULTS: A 22-year-old man developed bilateral corneal ectasia after SMILE. The preoperative corneal topography of the right eye was unremarkable, with a minimum corneal thickness of 511 µm in the right eye, and the abnormal corneal topography of the left eye revealed a risk factor for developing ectasia, with a minimum corneal thickness of 514 µm in the left eye. The refractive error was -4.50 to 3.50 × 10 degrees in his right eye and -4.25 to 3.50 × 0 degrees in his left eye with a best-corrected visual acuity of 20/20. An uncomplicated SMILE was performed; after his last follow-up visit at 1 month, the patient was lost to follow-up for 3 years. After that time, he presented with visual loss with left predominance. Bilateral ectasia was diagnosed through corneal topography, and crosslinking was performed in both eyes. CONCLUSIONS: There are a very few reports of corneal ectasia after SMILE with normal preoperative topography.

REVERSIBLE BILATERAL SUBFOVEAL ELLIPSOID ZONE FOCAL THICKENING ASSOCIATED WITH OVERDOSE OF PHOSPHODIESTERASE TYPE 5 INHIBITORS INTAKE.

PURPOSE: To describe the clinical findings and outcome of an unusual case of subfoveal yellowish deposits associated with excessive doses of phosphodiesterase Type 5 inhibitors intake. METHODS: Single retrospective case report. RESULTS: A 50-year-old South American man with a personal history of multiple orally administered phosphodiesterase Type 5 inhibitors drugs to treat a chronic erectile dysfunction complained of dyschromatopsia, photophobia, and a 3-month history of blurred vision. The fundus examination revealed a symmetrical yellowish lesion in both eyes with a subfoveal hyperreflective signal on the spectral domain optical coherence tomography at the level of the ellipsoid zone. Dysregulation of the blue-yellow axis was noticed in the color vision test and the electroretinogram demonstrated a tiny decrease in the b-wave amplitude. The use of phosphodiesterase Type 5 inhibitors was discontinued and the patient was examined 3 months later. Optical coherence tomography revealed complete disappearance of the deposit in both eyes and the associated symptoms resolved rapidly with discontinuation of the drug. CONCLUSION: A bilateral ellipsoid zone subfoveal focal thickening may be related to a yellowish symmetrical spot on the fovea in patients with a history of phosphodiesterase Type 5 inhibitors overdose intake. Functional and structural findings are reversible in a short-term period after discontinuing the oral treatment.

Clinical Outcomes of Femtosecond Laser-Assisted Implantation of Asymmetric ICRS in Keratoconus With No Coincidence of Topographic and Comatic Axes.

PURPOSE: To analyze the clinical outcomes obtained with asymmetric intracorneal corneal ring segments (ICRS) of variable thickness and width in patients with keratoconus, identifying predictive parameters of the final visual outcome. METHODS: This prospective, longitudinal, non-comparative clinical trial enrolled 35 eyes of 27 patients with keratoconus with a significant difference among corneal topographic and comatic axes. All eyes underwent implantation of AJL-pro+ ICRS (AJL Ophthalmic). Visual, refractive, corneal topographic and aberrometric, and pachymetric changes were evaluated during a 3-month follow-up. RESULTS: Significant changes were detected at 3 months after surgery in manifest sphere and cylinder, spherical equivalent, overall blur strength, and corrected distance visual acuity (CDVA) (P < .001). No losses of two or more lines of CDVA were observed, whereas 94.3% (33) of eyes gained one or more lines of CDVA. Keratometric readings and the magnitude of anterior corneal astigmatism were significantly reduced with surgery (P < .001), as well as the levels of corneal coma (P < .001) and spherical aberration (P = .007). Likewise, a significant change toward less prolateness was observed (P < .001). Significant correlations were found among the change in CDVA and preoperative CDVA (r = -0.532, P = .001), and between the change in primary coma root mean square and the preoperative level of spherical aberration (r = -0.542, P = .001) and coma root mean square (r = -0.719, P < .001). CONCLUSIONS: The implantation of the ICRS evaluated in keratoconus with no coincidence between topographic and comatic axes regularizes the corneal shape and reduces the level of higher order aberrations, inducing a significant visual improvement. [J Refract Surg. 2021;37(10):693-699.].

Refractive changes of a new asymmetric intracorneal ring segment with variable thickness and base width: A 2D finite-element model.

PURPOSE: To evaluate the local geometric effects of a unilateral intrastromal ring segment with a combined variation of ring thickness and base width in a finite element simulation, and to compare it against the isolated effect of thickness or base width variation alone. METHODS: A two-dimensional finite-element model of a transversely isotropic cornea was created assuming either axisymmetric stress or plane strain condition. The model geometry was composed of a three-layered corneal tissue (epithelium, anterior and posterior stroma) fixed at the limbus. The implantation of a triangular-shape asymmetric ring segment with varying ring thickness (150 to 300 µm) and base width (600 to 800 µm) was simulated. Also, changes induced by thickness or base width alone were studied and compared their combined effect in the asymmetric ring segment. Geometrical deformation of the simulated cornea and sagittal curvature were the main parameters of study. RESULTS: Increasing ring thickness and base width along the arc of the asymmetric ring segment produced a more pronounced flattening in this part of the ring. The asymmetric design did find a good balance between maximizing corneal flattening at one end and minimizing it at the other end, compared to the isolated effect of ring thickness and width. Ring thickness was the most robust parameter in flattening both, the central and peripheral cornea. CONCLUSION: The finite-element model permitted a theoretical study of corneal deformation undergoing implantation of realistic and hypothetical ring geometries. Intracorneal asymmetric ring segments with varying thickness and base width can be a good alternative in corneas with asymmetric keratoconus phenotypes.

Primary surgical options for acute corneal hydrops: A review.

Acute corneal hydrops usually resolves alone or with medical therapy along the first 4-6 weeks. However, depending on the severity of the corneal edema or the size of the Descemet break, self-healing might be difficult. Years ago, those patients had no more options than corneal transplantation, but surgical alternatives are on the rise in this century. These surgeries are becoming more popular with a variety of techniques relegating penetrating keratoplasty to a residual role. These techniques aim to accelerate corneal healing, reduce the edema, improve visual acuity and prevent from severe complications that may appear if corneal hydrops is not treated rapidly. Feasibility and safety are the favorable aspects of these techniques since the complications rates described remain low. In this review, we emphasize the recently published studies that describe both the techniques and their results.

Intrastromal Allogeneic Inclusions for the Management of Keratoconus: A Review of Current Literature.

ABSTRACT: A new therapeutic alternative has been developed in the past 6 years to treat severe keratoconus in young patients. Those patients had only corneal transplantation as an option, but now a variety of surgical alternatives in the form of allogeneic corneal inclusions have bloomed and are becoming more popular. Although Bowman layer transplantation is the most studied technique, recent studies have described different options with very promising preliminary results. Mostly all the techniques described improve corneal curvature, visual acuity, pachymetry, contact lens tolerance, and foremost, manage to avoid or postpone corneal transplantation. Very few complications have been described so far, which makes these techniques not only feasible but also safe. Herein, we focus on reviewing recently published studies describing these techniques and their first results.

In Vivo Confocal Microscopy Findings in Bowman Layer Transplantation.

PURPOSE: To report the in vivo confocal microscopy (IVCM) findings of a case who underwent femtosecond laser-assisted Bowman layer transplantation (BLT). METHODS: This is a case report. RESULTS: In a 25-year-old man with previous diagnosis of keratoconus in whom a BLT was performed using the femtosecond laser-assisted technique, IVCM (Confoscan 4; Fortune Technologies, Vigonza, Italy) was performed 3 months after surgery, obtaining a sequence of 4 digitalized images of the total thickness of the cornea, from the epithelium to the endothelium, and then backward. The images were analyzed with the Navis v. 3.5.0. system (NIDEK, Multi-Instrument Diagnostic System, Japan). In the anterior stroma, before arriving to the graft interphase, activated keratocytes could be observed with higher reflectivity. In this first image of the anterior interphase, a homogenous hyporreflective image could be observed. In the interior of the graft, no keratocytes were found and some hyperreflective particles were present. In addition to the anterior, the posterior interphase presented bright particles. CONCLUSIONS: This is the first report that documents a BLT using IVCM.

Long-term anatomical and functional outcomes after autokeratoplasty.

BACKGROUND: To evaluate the anatomical and functional outcomes of autologous contralateral penetrating keratoplasty (autokeratoplasty). METHODS: Kaplan-Meier survival analyses were retrospectively performed. Anatomical failure was defined as regraft or graft permanently cloudy at any time during follow-up. Functional failure was defined as the final best-corrected visual acuity (BCVA) <20/400. RESULTS: Thirty-one eyes of 31 patients (19 men), with a mean age of 52±18 years (range 15-81 years) were studied during a mean follow-up of 11.3 years (from 13 months to 48 years). At 12 months postoperatively, all the recipient eyes showed a transparent cornea, but 23% showed functional failure. At the final followup, 16 recipient eyes (52%) showed anatomical and functional success. Twenty-three eyes (74%) showed a clear cornea and 68% reached a better BCVA when compared with preoperative measurements. Nevertheless, 13/31 eyes (42%) displayed functional failure. The accumulative probabilities for anatomical success were 100%, 72% and 48% and 77%, 59% and 29% for functional success at 1, 10 and 40 years, respectively. The most common risk factor for failure was progression of previous glaucoma in 50% of the anatomical failures and in 77% of the functional failures. CONCLUSIONS: Autokeratoplasty could be a successful long-term option in patients having one eye with a clear cornea but with irreversible visual dysfunction and the contralateral eye having favourable visual potential limited only by a completely opacified cornea. Progression of previous glaucoma was the most important risk factor for long-term cornea decompensation and visual functional failure in the sample.

Visual and Anatomic Results After Sole Full-Thickness Sutures for Acute Corneal Hydrops.

PURPOSE: To determine whether sole full-thickness corneal sutures are a feasible treatment for acute corneal hydrops, and if so, report the anatomic and visual results of this technique. METHODS: A retrospective case series was carried out in 17 patients, all of whom received sole full-thickness sutures as a treatment for corneal hydrops. RESULTS: The included patients reported symptom commencement a median of 15 days before the surgical intervention. The patients' median preoperative corneal pachymetry was 1235 µm, whereas 1 month after the surgery, the median corneal thickness was 830 µm, and after 3 months, it was 502 µm (P < 0001). Preoperative best corrected visual acuity (BCVA) was 1.40 LogMAR and a final postsurgical BCVA of 1.00 LogMAR after 3 months of the follow-up (P < 0001). Deep neovascularization was present in 3 patients (17.6%); none of the patients developed cataract formations or pupillary blocks. CONCLUSIONS: Given the improvement of the corneal pachymetry and the BCVA, sole full-thickness sutures seem to be a feasible surgical option to treat severe acute corneal hydrops.

Bowman layer transplantation using a femtosecond laser.

We describe a variation of the original manual Bowman layer transplantation technique. After the isolation of the graft, a stromal pocket is created using a femtosecond laser. With the use of this technology, which entails preservation of the conjunctiva and the non-use of sutures, we avoid the scleral approach. The femtosecond laser proved to be a feasible surgical support of this technique.

Clinical and OCT Findings in a Case of a Presumed Perfluorooctane Retinal Acute Toxicity.

Retinal acute toxicity may be produced by several etiologies. Iatrogenic toxicity is one of the most-feared complications related to vitreoretinal surgery. The authors report a case of retinal acute toxicity due to the use of perfluorooctane during an uneventful retinal detachment surgery done elsewhere. The aim of this report is to describe the clinical and optical coherence tomography features of this complication, which unfortunately occurred in more than 100 cases in Spain. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:460-462.].

Methicillin-Resistant Staphylococcus aureus Acute Keratitis After Intracorneal Ring Segment Implantation.

INTRODUCTION: The purpose of this study was to report the first case of acute bacterial keratitis produced by methicillin-resistant Staphylococcus aureus after the implantation of two intracorneal ring segments during an uneventful procedure for treating keratoconus in a 13-year-old child. CASE REPORT: A patient with grade III keratoconus underwent an implantation of intracorneal ring segments with no complications during the procedure. Three days later, a whitish corneal infiltrate appeared in between the union of both corneal rings. Sample cultures were positive for methicillin-resistant S. aureus (MRSA). Corneal infiltrate did not improve despite intensive topical and systemic antibiotics. Melting appeared even after the explantation of both corneal rings. Keratoplasty à chaud had to be performed to preserve the eye integrity. CONCLUSIONS: MRSA keratitis following intracorneal ring segment implantation is a rare but severe complication that can lead to a therapeutic penetrating keratoplasty to definitely cure the process.