Aclaramiento corneal espontáneo tras desprendimiento del injerto en DMEK / Spontaneous corneal clearance after graft detachment in DMEK

El desprendimiento de la membrana de Descemet es una complicación potencial tras la queratoplastia endotelial de la membrana de Descemet (DMEK, acrónimo en inglés de Descemet membrane endothelial keratoplasty). En este artículo presentamos un caso clínico de una cirugía DMEK en un caso complicado, que presentó un desprendimiento casi completo del injerto y posteriormente una opacificación de este y la formación de una seudocámara anterior. En noviembre del 2020, se realizó una cirugía DMEK a un paciente de 64 años debido a una descompensación endotelial. Tres meses después del DMEK, se observó el injerto desprendido y parcialmente adherido, fibrótico en la cámara anterior y formando una seudocámara anterior. Sin embargo, la córnea se mantuvo totalmente transparente con un recuento endotelial de aproximadamente 1.204 células/mm2 y la agudeza visual con corrección fue 20/25. Tres meses más tarde, se objetivó una opacificación significativa del injerto despegado y la agudeza visual disminuyó a 20/63. Procedimos a la extracción del injerto sin realizar una segunda DMEK. Diez meses más tarde, la córnea permaneció transparente con un recuento endotelial de 510 células/mm2 y la agudeza visual con corrección fue 20/25 (AU)

Descemet Membrane detachment is a potential complication after Descemet Membrane Endothelial Keratoplasty (DMEK). Here, we present a unique case of a DMEK surgery in a complicated eye that suffered a nearly complete DMEK graft detachment and later a graft opacification with a pseudo-anterior chamber. In Mid-November 2020, a planned DMEK was performed in a 64-year-old male patient due to corneal decompensation. Four months after DMEK, a fibrotic DMEK graft was seen across the anterior chamber with a pseudo-anterior chamber; however, the recipient cornea showed complete clearance with an endothelial cell count of about 1204 cells/mm2 and a best-corrected visual acuity of 20/25. Three months later, we observed a significant opacification of the detached graft, and the best-corrected distance visual acuity decreased to 20/63. We proceeded with the graft removal without performing a second DMEK. Ten months after graft removal, the cornea remained clear with an endothelial cell count of about 510 cells/mm2, and the best-corrected visual acuity was 20/25 (AU)

Spontaneous corneal clearance after graft detachment in DMEK.

Descemet Membrane detachment is a potential complication after Descemet Membrane Endothelial Keratoplasty (DMEK). Here, we present a unique case of a DMEK surgery in a complicated eye that suffered a nearly complete DMEK graft detachment and later a graft opacification with a pseudo-anterior chamber. In Mid-November 2020, a planned DMEK was performed in a 64-year-old male patient due to corneal decompensation. Four months after DMEK, a fibrotic DMEK graft was seen across the anterior chamber with a pseudo-anterior chamber; however, the recipient cornea showed complete clearance with an endothelial cell count of about 1204 cells/mm2 and a best-corrected visual acuity of 20/25. Three months later, we observed a significant opacification of the detached graft, and the best-corrected distance visual acuity decreased to 20/63. We proceeded with the graft removal without performing a second DMEK. Ten months after graft removal, the cornea remained clear with an endothelial cell count of about 510 cells/mm2, and the best-corrected visual acuity was 20/25.

Clinical Outcomes of Sequential Intrastromal Corneal Ring Segments and an Extended Range of Vision Intraocular Lens Implantation in Patients with Keratoconus and Cataract.

PURPOSE: To evaluate efficacy, safety, and predictability of sequential Ferrara-type intrastromal corneal ring segments (ICRS) and an extended range of vision intraocular lens (IOL) implantation in patients with keratoconus and cataract. METHODS: This study comprised patients with keratoconus and cataract that had ICRS implantation followed 6 months later by extended range of vision IOL implantation. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and residual refractive errors, analysed using vector analysis, were recorded preoperatively, 6 months after ICRS implantation, and 6 months after IOL implantation, respectively. RESULTS: The study enrolled 17 eyes (11 patients). The mean UDVA (logMAR scale) was 1.15 ± 0.67 preoperatively, 0.88 ± 0.69 six months after ICRS implantation (P = 0.005), and 0.27 ± 0.18 six months after IOL implantation (P < 0.0001). The CDVA changed from 0.26 ± 0.15 (logMAR) before surgery to 0.17 ± 0.08 six months after Ferrara-type ICRS implantation (P = 0.002) and to 0.07 ± 0.06 six months after IOL implantation (P < 0.0001). The spherical equivalent and the refractive cylinder declined steeply after IOL implantation (P < 0.001). The magnitude of depth of focus was 2.60 ± 1.02 D. There were no statistically significant differences in visual acuity for a defocus range from +0.50 D to -0.50 D (P > 0.1). CONCLUSION: Sequential Ferrara-type ICRS and an extended range of vision IOL implantation provided good visual and refractive outcomes, being an effective, safe, and predictable procedure for the treatment of selected cases of patients with keratoconus and cataract. In addition, this approach provides an increase of tolerance to defocus.

Characterisation of the porcine eyeball as an in-vitro model for dry eye.

PURPOSE: To characterise the anatomical parameters of the porcine eye for potentially using it as a laboratory model of dry eye. METHODS: Anterior chamber depth and angle, corneal curvature, shortest and longest diameter, endothelial cell density, and pachymetry were measured in sixty freshly enucleated porcine eyeballs. RESULTS: Corneal steepest meridian was 7.85±0.32mm, corneal flattest meridian was 8.28±0.32mm, shortest corneal diameter was 12.69±0.58mm, longest corneal diameter was 14.88±0.66mm and central corneal ultrasonic pachymetry was 1009±1µm. Anterior chamber angle was 28.83±4.16°, anterior chamber depth was 1.77±0.27mm, and central corneal thickness measured using OCT was 1248±144µm. Corneal endothelial cell density was 3250±172 cells/mm2. CONCLUSIONS: Combining different clinical techniques produced a pool of reproducible data on the porcine eye anatomy, which can be used by researchers to assess the viability of using the porcine eye as an in-vitro/ex-vivo model for dry eye. Due to the similar morphology with the human eye, porcine eyeballs may represent a useful and cost effective model to individually study important key factors in the development of dry eye, such as environmental and mechanical stresses.

Long-Term Follow-up of Intrastromal Corneal Ring Segments (210-Degree Arc Length) in Central Keratoconus With High Corneal Asphericity.

PURPOSE: To assess the long-term outcomes of implanting intrastromal corneal ring segments (ICRSs) to correct central keratoconus with a high corneal asphericity value. METHODS: Forty-three eyes with central keratoconus with a corneal asphericity value ≥-1.00 were evaluated before and after implanting an inferior 210-degree arc-length Ferrara-type AFR5 ICRS (AJL Ophthalmic, Spain). Logarithm of the minimum angle of resolution uncorrected (UDVA) and best-corrected (CDVA) distance visual acuity, corneal asphericity, root mean square for coma-like aberrations [computed for the Zernike terms Z (3, 1) and Z (3, -1)], and residual refractive errors analyzed using vector analysis were recorded before and at all follow-up visits. The postoperative follow-up duration was 3 years in all cases. RESULTS: Mean UDVA (logarithm of the minimum angle of resolution scale) rose from 1.18 ± 0.59 to a postoperative 0.53 ± 0.39 after ICRS implantation (P < 0.0001). Mean CDVA varied in turn from 0.36 ± 0.18 to 0.17 ± 0.10 (P < 0.0001). CDVA remained unchanged or improved in all eyes after surgery. Both UDVA and CDVA were stable over the postoperative period (P > 0.05). The spherical equivalent declined steeply after ICRS implantation (P < 0.0001). Both spherical equivalent and refractive cylinder were stable over the postoperative period. The corneal asphericity and root mean square values for coma-like aberrations exhibited statistically significant decreases 6 months after ICRS implantation (P < 0.0001) and were also stable over postoperative follow-up (P > 0.05). CONCLUSIONS: These results suggest that implanting a single, inferior, 210-degree arc-length Ferrara-type ICRS is a safe, effective, and stable procedure for treating patients with central hyperprolate keratoconus.

Surgical Options for the Refractive Correction of Keratoconus: Myth or Reality.

Keratoconus provides a decrease of quality of life to the patients who suffer from it. The treatment used as well as the method to correct the refractive error of these patients may influence on the impact of the disease on their quality of life. The purpose of this review is to describe the evidence about the conservative surgical treatment for keratoconus aiming to therapeutic and refractive effect. The visual rehabilitation for keratoconic corneas requires addressing three concerns: halting the ectatic process, improving corneal shape, and minimizing the residual refractive error. Cross-linking can halt the disease progression, intrastromal corneal ring segments can improve the corneal shape and hence the visual quality and reduce the refractive error, PRK can correct mild-moderate refractive error, and intraocular lenses can correct from low to high refractive error associated with keratoconus. Any of these surgical options can be performed alone or combined with the other techniques depending on what the case requires. Although it could be considered that the surgical option for the refracto-therapeutic treatment of the keratoconus is a reality, controlled, randomized studies with larger cohorts and longer follow-up periods are needed to determine which refractive procedure and/or sequence are most suitable for each case.

Optical power distribution of refractive and aspheric multifocal contact lenses: Effect of pupil size.

PURPOSE: To evaluate the power profile within the optic zone of different designs of multifocal contact lenses (CLs) and to analyze how the effect of pupil size could impact on their optical performance. METHODS: The optical power distribution within the optic zones of multifocal CLs was measured by the Nimo TR1504 (LAMBDA-X, Belgium). The multifocal CLs under study were the Acuvue Bifocal, the Acuvue Oasys for Presbyopia, the PureVision Multifocal and the PureVision 2 for Presbyopia. Each design was considered in all their available addition powers. All lenses had a nominal power of -3.0D. At the same time, three lenses of each model were considered and five consecutive readings of each lens were performed. RESULTS: The results show that the PureVision Multifocal and the PureVision 2 for Presbyopia have aspheric power profiles. Both designs showed aspheric center-near designs with a smoother progression of the optical power in the PureVision 2 for Presbyopia. The Acuvue Bifocal and the Acuvue Oasys for Presbyopia are shown to have concentric alternating near and far zones. Apart from the refractive rings, the Acuvue Oasys for Presbyopia showed an increase in negative (or less positive) values toward the periphery of the lens. CONCLUSIONS: Besides the refraction, the knowledge of the power profiles of multifocal CLs and the effect of pupil size on the optical distribution of these lenses could be crucial to understand the performance of these designs when they are fitted.

In vitro optical performance of a new aberration-free intraocular lens.

PURPOSE: To assess the optical performance of the new EnVista intraocular lens (IOL). MATERIALS AND METHODS: Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL's aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield once they are implanted, an average corneal-aberration pattern was juxtaposed to the in-vitro profiles and the same parameters were calculated again. RESULTS: For the IOL-only scenario (ie, without including the corneal factor), it was the EnVista IOL, which is aberration-free that showed the higher MTF, PSF values. This was followed by the other two aberration-free IOL models. However, when the effect of an average corneal pattern was also taken into consideration, the AcrySof IQ IOL SN60WF always outperformed the other neutral-asphericity IOLs. CONCLUSIONS: The in-vitro optical performance of the EnVista IOL was good, but it decreases substantially in a whole-eye scenario, when the wavefront profile of an average cornea is added. Other designs with different degrees of SA should be considered for this IOL in order to surpass these results.