Technique of corneal allogenic ring segment preparation using femtosecond laser: preclinical study on human corneal grafts.

PURPOSE: To describe a new technique for preparing corneal allogenic ring segments (CAIRSs) using femtosecond laser technology. SETTING: Hospital Foundation Adolphe de Rothschild-Noémie de Rothschild institute, Paris, France. DESIGN: Preclinical study conducted on human corneal grafts. METHODS: The corneal grafts were mounted on an artificial chamber pressurizer (ACP) with preset constant pressure, and the FSL was used to create a circular annulus with specific dimensions. The resulting CAIRSs were analyzed for their thickness and width after air drying. RESULTS: A total of 25 CAIRSs were prepared using the FSL. The mean width and thickness of the CAIRSs were 803 ± 77 µm and 83 ± 16 µm, respectively. Statistical analysis revealed no significant differences in width among the various quadrants of each CAIRS or between different CAIRSs. Significantly thicker CAIRSs were obtained with a higher ACP pressure. CONCLUSIONS: The technique of CAIRS preparation using FSL technology and controlled artificial anterior chamber pressure demonstrated reproducibility and precision. This approach holds the potential for customizing and personalizing CAIRSs based on individual corneal characteristics.

Intra-Observer and Inter-Observer Variability of Intraocular Lens Measurements Using an Interferometry Metrology Device.

The NIMO TEMPO (Lambda-X, Nivelles, Belgium) is a novel, user-friendly and compact device designed for in vitro optical analysis of refractive and diffractive intraocular lenses (IOLs). This device analyzes the IOL wavefront and generates a synthetic eye model for numerical computation. The objective of this study was to evaluate the precision of this innovative device. Intra- and inter-observer variability were calculated using a two-way analysis of variance (ANOVA) after conducting ten measurements of eight different IOL models, with each measurement being repeated by three distinct operators (resulting in a total of 30 measurements for each IOL). The device demonstrated satisfactory intra- and inter-observer variability in evaluating IOL power and modulation transfer function (MTF) profiles, with values of 0.066 and 0.078 diopters for IOL power and 0.018 and 0.019 for MTF measurements, respectively. Furthermore, this hybrid optical and numerical in vitro IOL wavefront analyzer appears to have several advantages over conventional optical bench devices. It reduces the need for operator manipulation, and allows for numerical modeling of various optical environments, including cornea models and apertures. In conclusion, this novel metrology device designed for refractive and diffractive IOLs appears to provide a satisfactory precision, making it a promising tool in the field of IOL metrology.

Long-Term Follow-Up of Descemet Stripping Only: Data Up to 7 Years Postoperatively.

PURPOSE: The aim of this study was to report long-term follow-up of eyes undergoing Descemet stripping only (DSO). METHODS: This was a retrospective study including 26 eyes of 20 patients undergoing DSO between December 2015 and November 2022. Eligibility criteria included peripheral endothelial cell count (ECC) >1000 cells/mm2 and symptoms caused by central guttata. Patients underwent a central circular 4-mm descemetorhexis using a reverse Sinskey hook and a pair of descemetorhexis forceps using a peeling technique. Three parameters were measured before surgery and at last follow-up: best-corrected visual acuity (BCVA), central corneal thickness (CCT), and ECC measured centrally and at the periphery. RESULTS: The mean age was 73 ± 9 years [52-90 years]. The average follow-up period was 23.7 ± 24.8 months [3-84]. Twenty-two eyes responded to DSO with 20 female eyes (91%) and 2 male eyes (9%). The mean postoperative BCVA improved from 0.3 ± 0.17 logMAR to 0.09 ± 0.13 logMAR (P value <0.05). The mean postoperative CCT decreased from 588 ± 41 µm to 546 ± 50 µm (P-value <0.05). The mean postoperative central ECC was 780 ± 257 cells/mm2 [484-1500]. Peripheral ECC decreased postoperatively (1837 ± 407 cells/mm2 preoperatively to 864 ± 340 cells/mm2 postoperatively, P value >0.05). Peripheral endothelial cell polymegathism was stable (average of 26.8% ± 6.8% preoperatively and 30.2% ± 14% postoperatively). Average peripheral endothelial cells polymorphism decreased postoperatively (63.1 ± 20.5% preoperatively to 33% ± 25% postoperatively, P value >0.05). Four eyes did not show improvement after DSO and underwent Descemet membrane endothelial keratoplasty surgery. There were 3 men (75%) and 1 women (25%). The preoperative trend was for nonresponders to have lower BCVA, higher CCT, more abnormal peripheral polymorphism, and polymegathism. CONCLUSIONS: The results of this study, with up to 7 years follow up, demonstrate the durability of DSO.

Medium to long term follow up study of the efficacy of cessation of eye-rubbing to halt progression of keratoconus.

Purpose: To study the progression of keratoconus after cessation of eye rubbing with a minimum follow up of three-years. Design: Retrospective, monocentric, longitudinal cohort study of keratoconus patients with a minimum of 3 years follow-up. Participants: One hundred fifty three eyes of seventy-seven consecutive patients with keratoconus were included. Methods: Initial examination consisted of anterior and posterior segment evaluation using slit-lamp biomicroscopy. At the initial visit, patients were thoroughly informed of their pathology and instructed to stop rubbing their eyes. Eye rubbing cessation was assessed at all the follow-up visits at 6 months, 1 year, 2 years, 3 years, and yearly afterward. Corneal topography using the Pentacam® (Oculus®, Wetzlar, Germany) was used to obtain maximum and average anterior keratometry readings (Kmax and Kmean), as well as thinnest pachymetry (Pachymin, µm) in both eyes. Main outcome measures: The main outcomes measured were maximum keratometry (Kmax), mean keratometry (Kmean), and thinnest pachymetry (Pachymin) values at various time points to assess for keratoconus progression. Keratoconus progression was defined as a significant augmentation of Kmax (>1D), Kmean (>1D), or significant diminution of Pachymin (>5%) throughout the total follow-up duration. Results: One hundred fifty three eyes of seventy-seven patients (75.3% males) aged 26.4 years old, were followed for an average of 53 months. Over the course of the follow-up, there was no statistically significant variation of ∆Kmax (+0.04 ± 0.87; p = 0.34), ∆ Kmean (+0.30 ± 0.67; p = 0.27) nor ∆Pachymin (-4.36 ± 11.88; p = 0.64). Among the 26 of the 153 eyes which had at least one criterion of KC progression, 25 admitted continuing eye rubbing, or other at-risk behaviors. Conclusion: This study suggests that a significant proportion of keratoconus patients are likely to remain stable if close monitoring and strict ARB cessation are achieved, without the need for further intervention.

Relapsing-remitting Optic Neuropathy in an HIV-infected Patient: Secondary Auto-immune Optic Neuropathy or Infectious Optic Neuropathy? A Case Report and Review of the Literature.

It can be challenging to disentangle human immunodeficiency virus (HIV)-related infectious optic neuropathy and secondary triggered auto-immune disease when an HIV positive patient presents with vision loss. We report a 44-year-old untreated HIV positive Congolese woman who presented with two episodes of vision loss associated with pain in first her left eye and then her right eye and was diagnosed with a relapsing optic neuropathy. A correlation was observed between the clinical activity and cerebrospinal fluid viral load, CD4-count in the blood and magnetic resonance imaging signs of blood - optic nerve barrier breakdown. CD4 cell counts and viral loads are great clinical features to identify the type of acute optic neuropathy since differential diagnosis between an infectious optic neuropathy or an auto-immune induced optic neuropathy such as neuromyelitis optica spectrum disorder or immune reconstitution inflammatory syndrome can be puzzling.