Comparison of the effectiveness of different corneal curvature measurement methods for IOL implantation in traumatic aphakic eyes with corneal injury.

BACKGROUND/AIM: To assess the refractive outcomes of secondary intraocular lenses (IOL) in patients with traumatic aphakic eyes with corneal penetrating injury and compare different corneal curvature measurement methods. METHODS: Patients with unilateral penetrating eye injuries underwent corneal wound repair and cataract extraction, followed by secondary IOL implantation. Corneal curvature measurements were taken on the contralateral healthy eye (Group A), from the affected eye before removing corneal sutures (Group B), or after suture removal (Group C). The refractive outcomes were compared among the three groups. RESULTS: The study included 261 eyes. The Mean Absolute Error (MAE) in Group C (0.99 ± 0.85 D) was significantly smaller than that in Group A (1.87 ± 1.71 D) and Group B (1.37 ± 1.20 D) (both P < 0.001). Moreover, the percentage of eyes with IOL prediction errors within ± 0.50 D in Group C (40%) was higher than that in group A (21.7%) (OR = 2.364, 95%CI: 1.272-4.392, P = 0.006) and group B (28.0%) (OR = 1.714, 95%CI: 0.948-3.099, P = 0.073), and the percentage of eyes with IOL prediction errors within ± 1.0 D in Group C (90.9%) was higher than that in group A (67.9%) (OR = 4.758, 95%CI: 2.131-10.626, P < 0.001) and group B (75.0%) (OR = 3.370, 95%CI: 1.483-7.660, P = 0.003) as well. CONCLUSIONS: In traumatic aphakic eyes with corneal sutures, IOL power calculation based on the corneal curvature of the injured eye after removing the corneal sutures yields the best refractive outcomes.

Femtosecond laser-assisted cataract surgery in small pupils using non-aligned iris expansion ring without viscoelastic and corneal suture.

PURPOSE: To describe a technique for cataract surgery in eyes with small pupils that combines the use of the femtosecond laser and an iris expansion device, but without the use of corneal sutures and an ophthalmic viscosurgical device (OVD) at the time of laser application. METHODS: A retrospective case series of three eyes with small pupils were operated by the same surgeon without a corneal suture and with removal of anterior chamber OVD prior to laser application. RESULTS: Corrected distance visual acuity (CDVA) for 1 eye in a 70 year-old patient was 20/70 preoperatively and 20/20 thirty days postoperatively. CDVA for a second patient was 20/50 and 20/200 in the two eyes, which improved to 20/25 two months postoperatively in both eyes. There were no complications observed and the intraocular lens were well-centered. CONCLUSION: The use of mechanical pupil expander rings is safe and practical in setting small pupils during femtosecond laser-assisted cataract surgery.

Full- versus partial-thickness sutures: experimental models of corneal injury repair.

PURPOSE: To evaluate the performance of full-thickness (FT) versus partial-thickness (PT) sutures in a full-thickness corneal wound in an animal model. METHODS: This is a prospective, experimental, comparative, longitudinal study. A 6-mm linear, full-thickness corneal incision was performed on the right eye of eight domestic pigs. Eyes were randomly assigned for repair with interrupted PT (80-90% depth) sutures or FT 10-0 nylon sutures. Anterior segment OCT, corneal pachymetry and clinical photographs were obtained 1, 4 and 8 weeks postoperatively. Corneal thickness, depth of suture placement, perilesional edema, coaptation of wound edges and complications were noted. Histopathologic examination was performed at 8 weeks. RESULTS: 100% of the eyes with FT sutures developed a linear, less opaque scar. 100% of the eyes with PT developed a dense, opaque stromal scar (p = 0.02). Vascularization of the cornea was present in 75% of PT group and 25% in the FT group (p = 0.50). As the corneas healed, there was a marked trend toward thicker corneas in the PT group versus FT group with a median difference of - 63 µm at week 1 [median 788 µm vs. 725 µm, (p = 0.11)], - 38 µm at week 4, (724 µm vs. 686 µm, (p = 0.63)) and - 47 µm median difference at week 8 with (670 µm vs. 623 µm, (p = 0.06)). Histopathology showed disorganization of the collagen fibers and the formation of a retrocorneal fibrous membrane in the PT group. CONCLUSIONS: The FT group presented less corneal edema at week 8 with a more linear and less opaque scar. Histopathology showed a better-organized scar and endothelialization without the formation of a fibrous membrane.

Comparison of confocal microscopy and two-photon microscopy in mouse cornea in vivo.

High-resolution imaging of the cornea is important for studying corneal diseases at cellular levels. Confocal microscopy (CM) has been widely used in the clinic, and two-photon microscopy (TPM) has recently been introduced in various pre-clinical studies. We compared the performance of CM and TPM in normal mouse corneas and neovascularized mouse corneas induced by suturing. Balb/C mice and C57BL/6 mice expressing green fluorescent protein (GFP) were used to compare modalities based on intrinsic contrast and extrinsic fluorescence contrast. CM based on reflection (CMR), CM based on fluorescence (CMF), and TPM based on intrinsic/extrinsic fluorescence and second harmonic generation (SHG) were compared by imaging the same sections of mouse corneas sequentially in vivo. In normal mouse corneas, CMR visualized corneal cell morphologies with some background noise, and CMF visualized GFP expressing corneal cells clearly. TPM visualized corneal cells and collagen in the stroma based on fluorescence and SHG, respectively. However, in neovascularized mouse corneas, CMR could not resolve cells deep inside the cornea due to high background noise from the effects of increased structural irregularity induced by suturing. CMF and TPM visualized cells and induced vasculature better than CMR because both collect signals from fluorescent cells only. Both CMF and TPM had signal decays with depth due to the structural irregularity, with CMF having faster signal decay than TPM. CMR, CMF, and TPM showed different degrees of image degradation in neovascularized mouse corneas.

A cell-permeable peptide inhibitor of p55PIK signaling alleviates suture-induced corneal neovascularization and inflammation.

To prepare an ophthalmic solution with a cell-permeable TAT peptide (TAT-N24) as the main cell-permeable peptide inhibitor of p55PIK signaling and observe its therapeutic effect on suture-induced corneal neovascularization (CNV) in rats. Sprague-Dawley rats were used to establish a corneal suture (CS) model of CNV. The vehicle and 0.9% TAT-N24 ophthalmic solution was topically administered. CNV induction was assessed on the basis of the clinical performance of each group. Hematoxylin-eosin staining was used to observe pathological changes, and immunohistochemical staining and confocal immunofluorescence were used to determine the localization of factors associated with corneal tissue. The mRNA expression levels of hypoxia-inducible factor (HIF-1α), vascular endothelial growth factor (VEGF-A), nuclear transcription factor κB (NF-κB p65), tumor necrosis factor (TNF-α), interleukin-1ß (IL-1ß), and interleukin (IL)-6 were determined using real-time quantitative polymerase chain reaction. Western blotting was performed to detect the protein expression levels of HIF-1α and NF-κB p65. TAT-N24 slowed CNV production and reduced the expression of HIF-1α and inflammatory factors in CS models. The mRNA levels of HIF-1α, VEGF-A, NF-kB, TNF-α, IL-1ß, and IL-6 significantly decreased. Moreover, the protein levels of HIF-1α and NF-κB p65 were significantly decreased. TAT-N24 can treat CNV and ocular inflammation by inhibiting the HIF-1α/NF-κB signaling pathway in CS. In the early treatment of corneal foreign body trauma, topical application of TAT-N24 can not only reduce the inflammatory response but also inhibit corneal neovascularization.

Advantages of Double Running Sutures in Astigmatism After Penetrating Keratoplasty.

Background: The purpose of this prospective study is to evaluate the effects of different suturing techniques in perforating keratoplasty surgery, in order to identify the most effective in reducing post-operative astigmatism. Methods: We analysed data from patients who underwent penetrating keratoplasty for different indications. All interventions were performed by the same surgeon. Patients were subjected to a follow-up of at least 12 months after surgery, during which astigmatism (assessed by keratometry, topography and refraction) best-corrected visual acuity (BCVA) and complications were evaluated. A total of 100 eyes from 100 patients were included and were randomly assigned to five different groups, each one featuring a different suturing technique: interrupted (INT), single running (SRS), double running with two 10-0 sutures (DRS), double running antitorque with two 10-0 sutures (DRSa), double running with both 10-0 and 11-0 sutures (DRS with 11-0). Results: There is a statistically significant difference in astigmatism after surgery between the double running sutures groups and the others with different techniques. However, there is no statistically significant difference between the INT and the SRS group; moreover, there is no statistically significant difference between the different groups with double running sutures (DRS, DRSa, DRS with 11-0). There is no statistically significant difference in BCVA values among the five groups. The wound leak rate was 10% in the INT group, 5.3% in the SRS group and 0% in all groups with double running sutures. Conclusion: In penetrating keratoplasty surgery, the double running suture technique reduces postoperative astigmatism, provides faster visual rehabilitation and features lower complication rates when compared to techniques featuring single running and interrupted sutures. No significant difference in terms of postoperative astigmatism or complication rates was observed among patients receiving double running suture techniques.

Resident Skills Assessment in Corneal Suturing: A Comprehensive Review of Currently Proposed Educational Programs and Evaluation Tools.

Purpose This study aimed to perform a comprehensive review of publications proposing educational programs for resident skills assessment in corneal suturing. Methods An extensive online article search in PubMed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PISMA) reporting guidelines was performed to identify prospective comparative studies or prospective before/after studies published up to March 2021 and reporting the assessment of ophthalmology residents' skills in corneal suturing during dedicated training sessions. Results Three studies were identified for review. The first reported the efficiency of an electromagnetic tracking system placed on the surgeon's fingers coupled with a computer analysis of movements and time to identify surgeons with different backgrounds in corneal suturing. The second reported the efficiency of the reference system in assessing the improvement of corneal suturing conducted by residents after a training session, with video-based assessment for economy and confidence of movement, limiting tissue damage and precision of operative technique, reviewed by blind assessors. The third proposed an innovative remote corneal suturing training method using Zoom for direct feedback to the residents. The stitch quality was assessed for length, depth, radiality, and tension. The results were similar when compared with a group of residents without feedback. Conclusion This review underlines the rarity and disparity of available tools for corneal suturing assessment, justifying the need for more complete models to be designed. These should consider body ergonomics and stitch quality and time. Comparative studies involving novices and attendings may provide reliable evaluation of existing gaps and specific metrics to target, helping residents to approach their superiors' experience.