Peripheral Corneal Research Articles

Corneal melting after paclitaxel therapy in a case with intrastromal corneal ring segment (ICRS) implantation

Intrastromal corneal ring segments (ICRS) are small, crescent shaped plastic rings placed in the deep, peripheral corneal stroma to flatten the cornea. Corneal melting is a rare complication of ICRS implantation, with no long term effects reported. Although ocular toxicities are associated with paclitaxel (PTX), corneal melting from PTX therapy remains rare. Here we report a case of corneal melting in a patient who had ICRS implanted 20 years ago following recent PTX therapy for breast cancer. A 35 year old female patient presented with eye pain, photophobia, and blurry vision in her left eye, following a history of ICRS implantation 20 years ago. She was diagnosed with breast cancer 6 months ago and was undergoing PTX chemotherapy therapy. Ocular examination revealed bilateral meibomian gland dysfunction (MGD) and corneal melting in the left eye at the site of the corneal ring. Treatment initially included only eye drops mainly to promote epithelial repair and control inflammation. After 2 weeks, the corneal melting showed signs of healing; however, the patient continued complaining about eye pain and discomfort. Subsequently, amniotic membrane transplantation (AMT) and corneal contact lenses were initiated, leading to significant improvement after 2 months of treatment.

Missed intralenticular foreign body – A cause of ocular inflammation

A 36-year-old male presented with a complaint of glare since 2 months. He had a history of trauma to the left eye with copper wire 2 years back. At presentation, the visual acuity was 20/20 in both eyes. Anterior-segment evaluation of the left eye revealed peripheral corneal scar, anterior uveitis, and iris hole. Dilated evaluation revealed sunflower cataract, focal cortical cataract, and an intralenticular foreign body (ILFB). The posterior segment was normal. Inflammation was controlled with topical steroids, followed by ILFB removal, phacoaspiration, and intraocular lens implantation. A thorough dilated ocular examination is essential to rule out an intraocular foreign body in all the cases of penetrating ocular trauma.

Genetic and Functional Analyses of Patients with Marked Hypo-High-Density Lipoprotein Cholesterolemia.

This study aimed to analyze two cases of marked hypo-high-density lipoprotein (HDL) cholesterolemia to identify mutations in ATP-binding cassette transporter A1 (ABCA1) and elucidate the molecular mechanism by which these novel pathological mutations contribute to hypo-HDL cholesterolemia in Tangier disease. Wild type and mutant expression plasmids containing a FLAG tag inserted at the C-terminus of the human ABCA1 gene were generated and transfected into HEK293T cells. ABCA1 protein expression and cholesterol efflux were evaluated via Western blotting and efflux assay. The difference in the rate of change in protein expression was evaluated when proteolytic and protein-producing systems were inhibited. In case 1, a 20-year-old woman presented with a chief complaint of gait disturbance. Her HDL-C level was only 6.2 mg/dL. Tangier disease was suspected because of muscle weakness, decreased nerve conduction velocity, and splenomegaly. Whole-exome analysis showed compound heterozygosity for a W484* nonsense mutation and S1343I missense mutation, which confirmed Tangier disease. Cholesterol efflux decreased by a mixture of W484* and S1343I mutations. The S1343I mutation decreased the protein production rate but increased the degradation rate, decreasing the protein levels. This patient also had Krabbe disease. The endogenous ABCA1 protein level of macrophage cell decreased by knocking down its internal galactocerebrosidase. Case 2, a 51-year-old woman who underwent tonsillectomy presented with peripheral neuropathy, corneal opacity, and HDL-C of 3.4 mg/dL. Whole-exome analysis revealed compound heterozygosity for R579* and R1572* nonsense mutations, which confirmed Tangier disease. Case 1 is a new ABCA1 mutation with complex pathogenicity, namely, a W484*/S1343I compound heterozygote with marked hypo-HDL cholesterolemia. Analyses of the compound heterozygous mutations indicated that decreases in ABCA1 protein levels and cholesterol efflux activity caused by the novel S1343I mutation combined with loss of W484* protein activity could lead to marked hypo-HDL cholesterolemia. Galactocerebrosidase dysfunction could also be a potential confounding factor for ABCA1 protein function.

Multimodal Imaging of Posterior Corneal Opacities in Multicentric Osteolysis Nodulosis and Arthropathy (MONA).

Multicentric osteolysis nodulosis and arthropathy (MONA) syndrome is a rare autosomal recessive skeletal dysplasia. Caused by mutations in the matrix metalloproteinase 2 gene (MMP2) on chromosome 16q12, this syndrome has infrequently been associated with ophthalmic manifestations. Corneal opacities have been reported but not described or documented in detail. Complete ophthalmologic examination and multimodal anterior segment imaging were used to characterize the corneal findings in a patient with MONA syndrome. A 19-year-old with MONA syndrome was referred for an eye exam based upon MONA screening recommendations. Visually insignificant peripheral corneal opacities were noted. Anterior segment optical coherence tomography (AS-OCT) demonstrated posterior stromal and endothelial hyperreflectivity. Confocal microscopy demonstrated an acellular peripheral endothelium with a normal central endothelium. Corneal opacities can occur with MONA syndrome, which is caused by mutations in the MMP2 gene. In the patient presented here, the corneal opacities are peripheral, deep stromal, with sparing of the anterior stroma and epithelium.

Tomographic and topographic predictive factors of big bubble formation during deep anterior lamellar keratoplasty in keratoconus

PurposeTo identify preoperative predictors of big bubble (BB) formation during deep anterior lamellar keratoplasty (DALK) in patients with keratoconus (KC).MethodsDesignRetrospective cohort study in an Italian tertiary centre.Study populationConsecutive patients with...

Femtosecond Laser-Assisted Autologous Glueless Simple Limbal Epithelial Transplantation in Unilateral Limbal Stem Cell Deficiency: 12-Month Outcome of the First Clinical Cases.

Surgical treatment of unilateral limbal stem cell deficiency (LSCD) is based on limbal stem cell transplantation. Glueless simple limbal epithelial transplantation (G-SLET) technique implements several limbal micrografts harvested from the healthy eye of the same patient into the peripheral corneal tunnels without the use of fibrin glue and human amniotic membrane. A novel customized algorithm and software for a low-energy femtosecond laser (FSL) were developed and tested using 5 pairs of isolated porcine eyes. FSL-assisted G-SLET modification was assessed in 3 clinical cases of unilateral LSCD caused by chemical burns. Corneal epithelization efficacy, best-corrected visual acuity, corneal epithelial mapping, central corneal thickness, and impression cytology with immunohistochemical examination were evaluated. All patients were followed up for 12 months postoperatively. The FSL set for 100% energy and the pattern of 8 nonpenetrating vertical cuts with oblique tunnel portions having variable incision depths and diameter of 8.5 mm and higher were selected for further clinical evaluation. Clinically, stable corneal epithelialization was achieved 2 to 3 weeks after intervention. At the 6-month follow-up, all patients had a healthy corneal epithelium with limbal micrografts visible inside the corneal tunnels. Best-corrected visual acuity markedly improved in 2 cases, but not in the third case with severe corneal stromal scarring. In addition, all patients noted a full-scale reduction in subjective complaints and substantial improvement in their quality of life. The FSL-assisted G-SLET is a new technique for autologous limbal stem cell transplantation in patients with unilateral LSCD. It allows the standardization of corneal tunnel localization and dimensions, thereby increasing the safety of the surgical procedure.

Bioprinting of anisotropic functional corneal stroma using mechanically robust multi-material bioink based on decellularized cornea matrix

Corneal scarring is a common cause of blindness, affecting millions globally each year. A huge gap between the demand and supply of donor tissue currently limits corneal transplantation, the only definitive therapy for patients with corneal scarring. To overcome this challenge, researchers have harnessed the efficacy of 3D bioprinting to fabricate artificial corneal stromal constructs. With all the different bioinks available, the decellularized corneal matrix-based bioprinted construct can fulfill the required biological functionality but is limited by the lack of mechanical stiffness. Additionally, from a biophysical standpoint, it is necessary for an ideal corneal substitute to mimic the anisotropy of the cornea from the central optic zone to the surrounding periphery. In this study, we enhanced the mechanical robustness of decellularized cornea matrix (DCM) hydrogel by blending it with another natural polymer, sonicated silk fibroin solution in a defined ratio. Although hybrid hydrogel has an increased complex modulus than DCM hydrogel, it has a lower in vitro degradation rate and increased opaqueness due to the presence of crystalline beta-sheet conformation within the hydrogel. Therefore, we used this multi-material bioink-based approach to fabricate a corneal stromal equivalent where the outer peripheral corneal rim was printed with a mechanically robust polymeric blend of DCM and sonicated silk fibroin and the central optic zone was printed with only DCM. The bioprinted corneal stroma thus maintained its structural integrity and did not break when lifted with forceps. The two different bioinks were encapsulated with human limbus-derived mesenchymal stem cells (hLMSC) individually and 3D bioprinted in different patterns (concentric and parallel) to attain a native-like structure in terms of architecture and transparency. Thus, the bilayer cornea constructs maintained high cell viability and expressed keratocyte core proteins indicating optimal functionality. This approach helped to gain insight into bioprinting corneas with heterogeneous mechanical property without disturbing the structural clarity of the central optic zone.

The central and peripheral corneal response to short-term hypoxia.

To quantify the magnitude and recovery of central and limbal corneal oedema induced by short-term unilateral eyelid closure without contact lens wear. The left eye of 10 adults with healthy corneas was patched using a folded eye pad for 30 min. High-resolution optical coherence tomography images (which captured the limbal and central corneal regions simultaneously) were obtained before patching, immediately after eye opening and again at 1, 2, 5, 6, 9, 10, 14 and 15 mins after eyelid opening. Oedema was measured from the limbus (scleral spur) to the central cornea (thinnest corneal location) along the horizontal meridian. A greater amount of limbal oedema was noted (mean [SD] 3.84 [1.79] %) compared to the central cornea (2.48 [0.61] %; p = 0.04) after 30 mins of unilateral eyelid closure. Both central and limbal corneal oedema recovered rapidly following eyelid opening, with no significant differences in the rate of corneal recovery between corneal locations (p = 0.90). Short-term unilateral eyelid closure resulted in ~55% more relative oedema in the limbal region compared to the central cornea. Rapid recovery of oedema and corneal overshoot (thinning beyond the baseline corneal thickness) was observed within 1-2 min of eyelid opening for both central and peripheral regions.

Comparative analysis of surgically induced astigmatism following cataract surgery: influence of previous myopic correction and corneal parameters.

This retrospective study investigated the impact of corneal parameters on surgically induced astigmatism (SIA) in eyes with prior myopic correction undergoing cataract surgery. Department of Ophthalmology, San Marino Hospital, San Marino, Republic of San Marino. This case-control study analyzed existing data retrospectively, without randomization or masking. Eighty eyes divided in group 1 (40 eyes previous underwent refractive surgery for myopia) and group 2 ( 40 myopic eyes) that underwent cataract surgery with intraocular lens (IOL) implantation were included. SIA was calculated using values from the IOL Master Zeiss 700 and mean pupil power (MPP) derived from the CSO Sirius Topographer (based on 3mm pupil size) with vectorial analysis from doctor Hill software. No significant difference in SIA was observed between eyes with prior myopic photorefractive keratectomy and the control group (p > 0.05). SIA calculations using the IOL Master and CSO Sirius Tomographer yielded similar results. There was no significant correlation between SIA and axial length, corneal curvature, peripheral corneal thickness, or anterior chamber depth (p > 0.05). However, an inverse correlation was found between SIA and horizontal corneal diameter (p < 0.05). Corneal parameters, such as axial length, corneal curvature, peripheral corneal thickness, and anterior chamber depth, showed no significant influence on SIA. The inverse correlation between SIA and horizontal corneal diameter in study group suggests potential influence of white-to-white distance on SIA. These findings highlight the importance of considering corneal parameters for optimizing surgical outcomes.

Dupilumab‐related ocular surface disorders in a paediatric cohort with atopic dermatitis, treated in a tertiary paediatric hospital in London

AbstractBackgroundDupilumab is the first human monoclonal antibody approved for the treatment of moderate–severe atopic dermatitis (AD) in children from 6 years of age. Real‐world studies reviewing dupilumab‐related ocular surface disorders (DROSD) in the paediatric population are needed to detail ophthalmological findings.ObjectivesThis cross‐sectional observational study aimed to review the incidence, features, and ophthalmological findings of DROSD in a real‐world paediatric cohort, treated with dupilumab for AD.MethodsPharmacy and electronic medical records were used to identify all patients prescribed dupilumab for AD from April 2019 to July 2022. Data, including demographics, ocular signs and symptoms, severity and treatments, were collected and analysed.ResultsWe identified 46 patients, with a median age of treatment initiation of 12 years (range 9–14 years). Twelve patients (26.1%) developed DROSD. Mean time to development of DROSD was 4.1 months (±2.4 months, 95% confidence interval). Two patients (16.7%) with DROSD had severe eye findings including peripheral corneal opacification, one of which had reported only asymptomatic red eyes. Ocular signs included 91.7% (11/12) bulbar conjunctival injection, 41.7% (5/12) follicle involvement (limbal or forniceal), 25% (3/12) diffuse tarsal‐conjunctival thickening, 16.7% (2/12) featureless thickening, 16.7% (2/12) peripheral corneal opacification, 8.3% (1/12) cicatrisation and 8.3% (1/12) periorbital skin changes. No patients ceased treatment due to DROSD.ConclusionsThis study had a higher incidence of DROSD, compared to other real‐world paediatric studies but had a similar incidence to real‐world adult studies. Patient‐reported eye symptoms did not always correlate to severity of DROSD. Larger paediatric studies looking at the incidence and long‐term outcome of DROSD are needed.

Enhanced Migration of Fuchs Corneal Endothelial Cells by Rho Kinase Inhibition: A Novel Ex Vivo Descemet's Stripping Only Model.

Descemet's Stripping Only (DSO) is a surgical technique that utilizes the peripheral corneal endothelial cell (CEnC) migration for wound closure. Ripasudil, a Rho-associated protein kinase (ROCK) inhibitor, has shown potential in DSO treatment; however, its mechanism in promoting CEnC migration remains unclear. We observed that ripasudil-treated immortalized normal and Fuchs endothelial corneal dystrophy (FECD) cells exhibited significantly enhanced migration and wound healing, particularly effective in FECD cells. Ripasudil upregulated mRNA expression of Snail Family Transcriptional Repressor (SNAI1/2) and Vimentin (VIM) while decreasing Cadherin (CDH1), indicating endothelial-to-mesenchymal transition (EMT) activation. Ripasudil activated Rac1, driving the actin-related protein complex (ARPC2) to the leading edge, facilitating enhanced migration. Ex vivo studies on cadaveric and FECD Descemet's membrane (DM) showed increased migration and proliferation of CEnCs after ripasudil treatment. An ex vivo DSO model demonstrated enhanced migration from the DM to the stroma with ripasudil. Coating small incision lenticule extraction (SMILE) tissues with an FNC coating mix and treating the cells in conjunction with ripasudil further improved migration and resulted in a monolayer formation, as detected by the ZO-1 junctional marker, thereby leading to the reduction in EMT. In conclusion, ripasudil effectively enhanced cellular migration, particularly in a novel ex vivo DSO model, when the stromal microenvironment was modulated. This suggests ripasudil as a promising adjuvant for DSO treatment, highlighting its potential clinical significance.

Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review.

Among refractive errors, astigmatism is the most common optical aberration, where refraction changes in different meridians of the eye. It causes blurred vision at any distance and includes corneal, lenticular, and retinal astigmatism. Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism, for example, a large size surgery incision. The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery. Nowadays, three surgical approaches can be used. By placing a sutureless clear corneal incision on the steep meridian of the cornea, a preoperative corneal astigmatism less than 1.0 D can be corrected. Single or paired peripheral corneal relaxing incisions (PCRIs) provide 1.0-3.0 D corneal astigmatism correction. PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism, if more than 2.0 D, the risk of overcorrection and irregular astigmatism is increased. When toric intraocular lenses (IOLs) are unavailable in markets, PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism. Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism. Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D. These approaches can be used alone or in combination.

The Influence of Corneal Thickness on Surgically Induced Corneal Astigmatism Derived from Total Keratometry Measured by Anterior Segment Swept-Source OCT.

The purposeof the study was to explore the possible correlations between the anterior segment parameters derived from anterior segment swept-source optical coherence tomography (AS-SS-OCT) with the surgically induced corneal astigmatism (CSIA) calculated from total keratometry (TK) measured by AS-SS-OCT. Seventy-one eyes of 67 patients with age-related cataract who underwent phacoemulsification combined with intraocular lens implantation with 2.2-mm incision were included. The CSIA values were calculated from anterior keratometry (CSIAKant) and TK (CSIATK) measured by AS-SS-OCT, respectively. Hotelling's T2 test was used to evaluate the difference. The correlation of CSIA with various parameters derived from AS-SS-OCT was tested with the Spearman correlation coefficient. The centroid of CSIAKant and of CSIATK were 0.31 ± 0.55 D @ 54° and 0.41 ± 0.59 D @ 51°, with no significant difference (F = 1.283, p = 0.281, Hotelling's T2). The mean absolute CSIAKant and CSIATK were 0.58 ± 0.24 D and 0.65 ± 0.28 D. Spearman test showed that the magnitude of CSIAKant was negatively correlated with preoperative peripheral corneal thickness (PCT, p = 0.045) and the magnitude of anterior keratometry (p = 0.044). The magnitude of CSIATK was negatively correlated with preoperative central corneal thickness (CCT, p = 0.003) and preoperative PCT (p = 0.015). The increased thickness of the peripheral cornea is correlated with the decrease in the magnitude of the CSIA. The correlation we identified between the corneal thickness and the CSIA indicated that certain preoperative parameters should be considered for the prediction of CSIA for a more precise refractive outcome.

Keratorefractive lenticule extraction in eyes with post-herpetic scars

Correcting refractive errors by remodeling the corneal curvature with an excimer laser (which emits ultraviolet radiation) may reactivate a latent Herpes Simplex Virus (HSV), resulting in keratitis. New techniques using infrared sources, such as femtosecond-assisted Keratorefractive Lenticule Extraction (KLEx), may thus provide a safer approach to eyes with previous HSV keratitis; however, no cases of KLEx in such cases have been reported. As a result, we present three cases in which KLEx successfully corrected myopia. Three myopic eyes from three patients with a known history of healed HSV keratitis that occurred more than 12 months before surgery underwent KLEx. All patients received oral antiviral prophylaxis before and after surgery. In case 1, the post-HSV scar was semiperipheral, involving only a portion of the treated area; surgery went smoothly, with the intrastromal lenticule well delineated and dissected even through the scar. In cases 2 and 3, the healed scar was peripheral and did not interfere with surgery. After 6 months, all three cases had good visual acuity without complications. Finally, KLEx combined with antiviral prophylaxis can effectively correct myopia in eyes with healed HSV. The femtosecond laser can penetrate non-dense, peripheral corneal scars.

Outcomes of Descemet Stripping Only Without Postoperative Use of Topical Rho-Associated Protein Kinase Inhibitors.

Descemet stripping only (DSO) is a promising surgical option for select patients with Fuchs endothelial dystrophy (FED). There is growing support for the use of topical Rho-associated protein kinase inhibitors (ROCKi) to optimize DSO outcomes. However, in many settings, ROCKi are either unavailable or not approved to treat corneal diseases. This study sought to characterize patient outcomes after DSO in the absence of ROCKi and potentially broaden the settings where DSO can be offered to patients. Single-center retrospective case series of 15 eyes/11 patients (66 years; 52-74) that underwent DSO, alone or combined with cataract surgery, by one surgeon between August 2020 and January 2023. Patients included in analyses had FED with central guttae, no clinical evidence of corneal edema, and a clinically healthy peripheral corneal endothelium. Mean follow-up time was 14 months (2-34). Fourteen of 15 eyes achieved corneal clearance (93.3%). Mean time to clearance was 8.5 weeks (3-23). Eleven eyes (73%) achieved corrected distance visual acuity of ≤0.2 with a significant postoperative improvement at 4 to 8 months ( P < 0.05) and sustained improvements at >12 months. No significant astigmatism was introduced by the procedure. Two eyes developed cystoid macular edema postoperatively. A trend toward earlier clearance was observed in the <65 years old group. Despite a longer time to corneal clearance in this cohort compared with the few studies using ROCKi, the overall success rate and visual outcomes for the patients in our cohort supports the use of DSO in settings where ROCKi are not readily available.

The most common contact lens-related complications: A brief review of the literature

Introducion and purpose Millions of people use contact lenses every day. Their primary and most common use is correcting refractive errors. Despite their beneficial purpose, contact lens use has many complications. It is estimated that 5 to 50% of patients may develop at least a single complication. The state of knowledge Contact lens-related complications are multifactorial. One of the main reasons for contact lens discontinuation is contact lens discomfort. Patients most often report dryness, burning, and irritated eyes. Other disorders can be briefly divided into conjunctival and corneal complications. The most common conjunctival and allergic complication of contact lens use is giant papillary conjunctivitis. Other significant conditions involving the conjunctiva can also be superior limbic keratoconjunctivitis or allergic or toxic conjunctivitis. Corneal complications, on the other hand, seemed to be much more severe. These include superficial punctate keratitis, peripheral corneal ulceration, and contact lens-related keratitis. Also, abrasion can occur due to improper eye hygiene or mechanical damage during lens replacement. It should also be remembered that prolonged use of lenses can lead to hypoxia and corneal edema. Summary This paper briefly outlines the possible complications of contact lens use. It is important to remember that despite their appropriate use, sometimes significant complications can occur. Noteworthy, corneal, or conjunctival complications require discontinuation of the lenses and appropriate treatment.

Predicting the impact of femtosecond-assisted arcuate keratotomy combined with tri-planar clear corneal incisions on astigmatism in implantable collamer lens surgery: one-year follow-up.

To investigate the factors associated with and impact on the femtosecond-assisted (FS-assisted) limbal relaxing incision (LRI) combined with the steep-meridian tri-planar clear corneal incision (TCCI) to reduce astigmatism in patients undergoing Implantable Collamer Lens (ICL) surgery. Retrospective case series. The study reviewed patients with ICL surgery combined with FS-assisted LRIs paired with steep-meridian TCCIs. Correlation analysis examined the relationship between independent variables, including preoperative characteristics (intraocular pressure, corneal thickness, axial length, et al.), TCCI, and LRI surgical parameters. The predictors of surgically induced astigmatism (SIA) were determined using individual-level analysis and accounting for inter-eye correlation with the generalized estimating equation (GEE). The study enrolled 69 patients, with 114 eyes (55 right and 59 left). The mean spherical equivalent (SEQ) was - 10.29 ± 2.99D and - 9.99 ± 2.72D for the right and left eye, respectively, while the mean preoperative corneal astigmatism was - 1.54 ± 0.47D and - 1.54 ± 0.46D for the right and left eyes, respectively. After 12 months of follow-up, univariate analysis revealed significant correlations between SIA and intraocular pressure (IOP), astigmatism type, TCCI position (degree), peripheral corneal thickness (PCT), LRI arc incision diameter, post depth (%), and angle, respectively (P = 0.046, 0.016, 0.039, 0.040, 0.009, 0.000, 0.000). Multivariate analysis using GEE demonstrated that axial length (AL), astigmatism type, LRI arc diameter, and angle were independent predictors of SIA (P = 0.000, 0.005, 0.029, 0.000). The type of astigmatism and axial length were independent factors that affected SIA when modifying the LRI arc diameter and angle through FS-assisted steep-meridian TCCI paired with LRI in ICL surgery.

Small-diameter acellular porcine corneal stroma for peripheral corneal ulceration treatment.

To evaluate the clinical efficacy of small-diameter acellular porcine corneal stroma (SAPS) for the treatment of peripheral corneal ulceration (PCU). This retrospective clinical study included 18 patients (18 eyes) with PCU between April 2018 and December 2020. All patients had PCU and underwent lamellar keratoplasty with SAPS. Observation indicators included preoperative and postoperative best-corrected visual acuity (BCVA) and transparency of SAPS. The infection control rate in the surgical eye-lesion area was also calculated. Eighteen patients underwent lamellar keratoplasty with SAPS to treat PCU. None of the patients experienced rejection after 6mo (18/18) and 12mo (16/16) of follow-up. The BCVA (0.47±0.30) at the 6mo follow-up after operation was significantly improved compared with the baseline (0.99±0.80), and the difference was statistically significant (Z=-3.415, P<0.05). The BCVA at the 12mo follow-up after operation was not statistically significant compared to the 6mo (Z=0, P=1). With time, the SAPS graft gradually became transparent. At the 6mo (18/18) and 12mo (16/16) follow-up, none of the patients had recurrent corneal infection. SAPS is clinically effective in the treatment of PCU, improving the patient's BCVA and reducing the incidence of rejection after keratoplasty.

Association Between Corneal Changes and Retinal Oximetry in Diabetes Mellitus.

Diabetes mellitus (DM) causes different corneal changes that are associated with the severity of diabetic retinopathy. To identify the pathophysiological reasons for this, corneal tomography and optical densitometry (COD) were combined with retinal oximetry. Patients with DM and healthy subjects were included in this pilot study. Spatially resolved corneal thickness and COD were assessed using the Pentacam HR (Oculus). The pachymetry difference (PACDiff) was calculated as an indicator of an increase in the peripheral corneal thickness. Oxygen saturation (SO2) of the retinal vessels was measured using the Retinal Vessel Analyzer (Imedos Systems UG). Subsequently, the associations between corneal and retinal parameters were analyzed. Data from 30 patients with DM were compared with those from 30 age-matched healthy subjects. In DM, arterial (P = 0.048) and venous (P < 0.001) SO2 levels were increased, and arteriovenous SO2 difference was decreased (P < 0.001). In patients, PACDiff was higher than that in healthy subjects (P < 0.05), indicating a stronger increase in peripheral corneal thickness. The COD was reduced in DM (P = 0.004). The PACDiff of concentric rings with a diameter of 4 mm (r = -0.404; P = 0.033) to 8 mm (r = -0.522; P = 0.004) was inversely correlated with the arteriovenous SO2 difference. Furthermore, PACDiff 4 mm was negatively associated with arterial SO2 (r = -0.389; P = 0.041), and the COD of the peripheral corneal areas correlated positive with arterial SO2 (COD total 10-12 mm: r = 0.408; P = 0.025). These associations might indicate a common pathogenesis of corneal and retinal changes in DM, which could be caused by reduced oxygen supply, mitochondrial dysfunction, oxidative stress, and cytokine effects.

Redistribution of Epithelium and Stroma and Their Relationship With Corneal Curvature After 1-Month Cessation of Overnight Orthokeratology.

To investigate the changes in the thickness of epithelium and stroma and their relationship with corneal curvature following the cessation of overnight orthokeratology for a period of 1 month. This prospective study consecutively included 20 juveniles (20 right eyes) who had undergone overnight orthokeratology for a minimum of one year and were willing to discontinue the treatment. The study measured and compared epithelial and corneal curvature using optical coherence tomography and Medmont topographer at the first day of cessation and 1 month after cessation. In addition, changes in uncorrected visual acuity and refractive error before and after the cessation of the treatment were analyzed. The study found a significant increase in the thickness of the epithelium in the central 2-mm area after the cessation of the treatment (t = -4.807, P <0.001). Moreover, the stroma in the paracentral area (2-5 mm) and peripheral area (5-6 mm) showed a general thinning trend ( P =0.016, P =0.016). Regarding the correlation analysis, the change in central epithelial thickness (ΔCET) was significantly correlated with the change in paracentral corneal curvature (ΔPCCC) (r=0.610, P =0.007) and the change in peripheral corneal curvature (ΔPCC) (r=0.597, P =0.009). Similarly, the change in central stromal thickness (ΔCST) was significantly correlated with the change in central corneal curvature (ΔCCC) (r=0.500, P =0.035), ΔPCCC (r=0.700, P =0.001), and ΔPCC (r=0.635, P =0.005). The study found that the corneal remodeling induced by orthokeratology was reversible after the cessation of the treatment. Specifically, changes in the epithelium were found to be more prominent in the central area, while changes in the stroma were more pronounced in the paracentral and peripheral areas. In addition, the study established a significant correlation between central corneal remodeling and changes in curvature.