Decrease In Corneal Thickness Research Articles

Comprehensive combined analysis of physician-initiated phase II and III clinical trials on a cultured human corneal endothelial cell product for treating bullous keratopathy.

To evaluate the efficacy and safety of a cultured human corneal endothelial cell (cHCEC) product in eyes with bullous keratopathy (BK). Combined analysis of multicenter phase II and III clinical trials. This analysis involved 15 BK eyes in the phase II trial and 12 BK eyes in the phase III trial that underwent cHCEC transplant therapy. Safety was assessed in all the cases. Efficacy was assessed in 17 cases with exclusion of the low- and medium-dose groups in the phase II trial. The primary endpoint was a corneal endothelial cell density of 1000 cells/mm2 or more at 24 weeks post-transplant, which was attained in 94.1% of the eyes (16 of 17), with a 95% CI of 71.3-99.9%. Additionally, 82.4% of the eyes (14 of 17) met the secondary endpoint of reduction in corneal thickness to less than 630 µm without corneal epithelial edema within the same time frame, with a 95% CI of 56.6-96.2%. The mean decrease in corneal thickness from baseline to 24 weeks post-transplant was -187.4 µm (95% CI, -240.2 µm to -134.5 µm). Furthermore, all the eyes exhibited improvement in best-corrected visual acuity from baseline to 24 weeks post-transplant (95% CI, 80.5-100.0%). By 24 weeks post-transplant, 88.9% of the patients (24 of 27) had experienced adverse events, which were mostly local, mild, and transient. The cHCEC product of this study reconstitutes the corneal endothelial layer with high cellular density and restores corneal thickness and improves visual acuity.

Safety and Efficacy of Epithelium-Off Corneal Collagen Cross-Linking for the Treatment of Corneal Ectasia: A Report by the American Academy of Ophthalmology

To review the evidence on the safety and effectiveness of epithelium-off corneal collagen cross-linking (CXL) for the treatment of progressive corneal ectasia. A literature search of the PubMed database was most recently conducted in March 2024 with no date restrictions and limited to studies published in English. The search identified 359 citations that were reviewed in abstract form, and 43 of these were reviewed in full text. High-quality randomized clinical trials comparing epithelium-off CXL with conservative treatment in patients who have keratoconus (KCN) and post-refractive surgery ectasia were included. The panel deemed 6 articles to be of sufficient relevance for inclusion, and these were assessed for quality by the panel methodologist; 5 were rated level I, and 1 was rated level II. There were no level III studies. This analysis includes 6 prospective, randomized controlled trials that evaluated the use of epithelium-off CXL to treat progressive KCN (5 studies) and post-laser refractive surgery ectasia (1 study), with a mean postoperative follow-up of 2.4 years (range, 1-5 years). All studies showed a decreased progression rate in treated patients compared with controls. Improvement in the maximum keratometry (Kmax) value, corrected distance visual acuity (CDVA), and uncorrected distance visual acuity (UDVA) was observed in the treatment groups compared with control groups. A decrease in corneal thickness was observed in both groups but was greater in the CXL group. Complications were rare. Epithelium-off CXL is effective in reducing the progression of KCN and post-laser refractive surgery ectasia in most treated patients with an acceptable safety profile. Proprietary or commercial disclosure may be found after the references.

Evaluation of Mooren's corneal ulcer by anterior segment optical coherence tomography

BackgroundThis study evaluates the use of anterior segment optical coherence tomography (AS-OCT) to identify focal changes and inform surgical plans in eyes with Mooren's ulcer. MethodsA total of 18 eyes of 17 patients with Mooren's ulcer were examined prospectively using the AS-OCT system. ResultsOptical hyperreflectivity noted on AS-OCT images was in accordance with corneal ulceration, neovascularization, fibrovascular membranes, the junction of the native stromal bed, and the overlying lamellar corneal grafts. Focal corneal ectasia was observed in 13 eyes with a decrease in corneal thickness to ≤0.39 mm. There was a cut-off value of 0.39 mm in corneal thickness between the eyes with and without focal corneal ectasia in the thinned corneal area (Fisher = 0.383, χ2 = 14.873, P = 0.000). Based on the AS-OCT findings, six eyes were subjected to an individualized lamellar corneal graft. The thickness of the residual cornea after surgery was 47 ± 34 μm less than the presumed healthy corneal thickness before surgery (t = 3.376, P = 0.02). A small corneal perforation covered by a pseudopterygium in Mooren's ulcer was found through AS-OCT but undetectable by slit-lamp biomicroscopy. ConclusionsAS-OCT is a valuable non-contact technique for monitoring corneal thinning in Mooren's ulcer, and assisting surgical design. A decrease in peripheral corneal thickness to ≤0.39 mm may cause focal corneal ectasia.

Age-Related Differences in Ocular Features of a Naturalistic Free-Ranging Population of Rhesus Macaques.

Rhesus macaques (Macaca mulatta) are the premier nonhuman primate model for studying human health and disease. We investigated if age was associated with clinically relevant ocular features in a large cohort of free-ranging rhesus macaques from Cayo Santiago, Puerto Rico. We evaluated 120 rhesus macaques (73 males, 47 females) from 0 to 29 years old (mean ± SD: 12.6 ± 6.4) from September to December 2021. The ophthalmic evaluation included intraocular pressure (IOP) assessment, corneal pachymetry, biomicroscopy, A-scan biometry, automated refraction, and fundus photography after pupil dilation. The associations of age with the outcomes were investigated through multilevel mixed-effects models adjusted for sex and weight. On average, IOP, pachymetry, axial length, and automated refraction spherical equivalent were 18.37 ± 4.68 mmHg, 474.43 ± 32.21 µm, 19.49 ± 1.24 mm, and 0.30 ± 1.70 diopters (D), respectively. Age was significantly associated with pachymetry (β coefficient = -1.20; 95% confidence interval [CI], -2.27 to -0.14; P = 0.026), axial length (β coefficient = 0.03; 95% CI, 0.01 to 0.05; P = 0.002), and spherical equivalent (β coefficient = -0.12; 95% CI, -0.22 to -0.02; P = 0.015). No association was detected between age and IOP. The prevalence of cataracts in either eye was 10.83% (95% CI, 6.34-17.89) and was significantly associated with age (odds ratio [OR] = 1.20; 95% CI, 1.06-1.36; P = 0.004). Retinal drusen in either eye was observed in 15.00% (95% CI, 9.60-22.68) of animals, which was also significantly associated with age (OR = 1.14; 95% CI, 1.02-1.27; P = 0.020). Rhesus macaques exhibit age-related ocular associations similar to those observed in human aging, including decreased corneal thickness, increased axial length, myopic shift, and higher prevalence of cataract and retinal drusen.

Efficacy of customized corneal crosslinking versus standard corneal crosslinking in patients with progressive keratoconus (C-CROSS study): study protocol for a randomized controlled trial

BackgroundKeratoconus is a degenerative disorder of the cornea leading to a protrusion and thinning with loss of visual acuity. The only treatment to halt the progression is corneal crosslinking (CXL), which uses riboflavin and UV-A light to stiffen the cornea. Recent ultra-structural examinations show that the disease is regional and does not affect the entire cornea. Treating only the affected zone with CXL could be as good as the standard CXL, that treats the entire cornea.MethodsWe set up a multicentre non-inferiority randomized controlled clinical trial comparing standard CXL (sCXL) and customized CXL (cCXL). Patients between 16 and 45 years old with progressive keratoconus were included. Progression is based on one or more of the following changes within 12 months: 1 dioptre (D) increase in keratometry (Kmax, K1, K2); or 10% decrease of corneal thickness; or 1 D increase in myopia or refractive astigmatism, requiring corneal crosslinking.DiscussionThe goal of this study is to evaluate whether the effectiveness of cCXL is non-inferior to sCXL in terms of flattening of the cornea and halting keratoconus progression. Treating only the affected zone could be beneficial for minimalizing the risk of damaging surrounding tissues and faster wound healing. Recent non-randomized studies suggest that a customized crosslinking protocol based on the tomography of the patient’s cornea may stop the progression of keratoconus and result in flattening of the cornea.Trial registrationThis study was prospectively registered at ClinicalTrials.gov on August 31st, 2020, the identifier of the study is NCT04532788.

Early influence of endotamponade on corneal biomechanical parameters, central corneal thickness and accuracy of intraocular pressure measurement

To define the influence of air, SF6 gas and silicon oil 1000cs tamponade injection and oil tamponade removal on corneal biomechanics, central corneal thickness and intraocular pressure. 77 eyes referred to vitrectomy were divided into 4 groups: 19 to air tamponade, 21 to SF6 tamponade, 19 to oil tamponade, 18 to oil tamponade removal. Pre- and postoperative corneal hysteresis, corneal resistance factor, corneal thickness, Goldman intraocular pressure (GAT) and corneal compensated intraocular pressure (IOPcc) were analysed. GAT and IOPcc did not change after the air or SF6 tamponade. The oil tamponade injection caused increase in GAT and IOPcc, while the oil removal caused reduction in those parameters. In all groups, preoperative and postoperative values of GAT and IOPcc did not differ. There was no change in corneal thickness and biomechanics after air, SF6 or oil tamponade while after removal of oil those parameters are decreased. The air, SF6 and oil tamponade does not change the corneal thickness and corneal biomechanics. The removal of oil causes decrease in corneal thickness and biomechanics which can lead to bias in intraocular pressure measurement. GAT and IOPcc did not differ in eyes pre- and post-vitrectomy, being similarly reliable measure.

Direct assessment of changes in biomechanical properties of the cornea after ReLEx SMILE and FemtoLASIK surgeries

The SMILE group comprised 23 patients (46 eyes) with spherical refraction -3.8±1.8 diopters (D), the FemtoLASIK group included 18 patients (36 eyes) with spherical refraction -3.5±1.3 D. Analysis of the biomechanical properties of the cornea was carried out using the CORVIS ST device (Oculus, Germany) before and seven days after corneal refractive surgery. In the SMILE group, with intraoperative decrease in corneal thickness of 91.43±19.43 µm, a significant increase in the following parameters was observed: deformation coefficient (DA ratio; p=0.0001), peak distance (PD; p=0.02) and inverse concave radius (ICR; p=0.003); a decrease in the stiffness parameter at first applanation (SP-A1; p=0.0001), Corvis biomechanical index (CBI; p=0.0001), intraocular pressure (IOP; p=0.001). In the FemtoLASIK group, with intraoperative decrease in corneal thickness of 75.33±32.3 µm, we observed a significant increase in DA ratio (p=0.0002), PD (p=0.04), ICR (p=0.0002), a decrease in SP-A1 (p<0.0001), IOP values (p=0.0003). In comparison with the FemtoLASIK group, the deformation amplitude DA changed significantly less in the SMILE group (p=0.04). In the FemtoLASIK group, in comparison with the SMILE group, the DA ratio (p=0.0009) and SP-A1 (p=0.0003) significantly increased. Intraoperative corneal thickness change correlates with ICR both in SMILE (R=0.52) and in FemtoLASIK (R=0.65). Corneal biomechanical properties determined with CORVIS ST in eyes with mild to moderate myopia change to a lesser extent after ReLEx SMILE compared to FemtoLASIK.

Protective effect of Tisochrysis lutea on dry eye syndrome via NF-κB inhibition

Dry eye syndrome (DES) affects the cornea, causes pain and hypersensitivity to light. Although inflammation and endoplasmic reticulum stress are known to be involved, the detailed mechanisms remain unknown. DES is characterized by a decrease in corneal thickness, tear volume, and lacrimal gland size, and damage to corneal cells. Tisochrysis lutea is a microalga that has been shown to reduce immune factors. Therefore, we hypothesized that T. lutea could ameliorate DES. We investigated the role of T. lutea in scopolamine-induced DES in BALB/c mice. Oral administration of T. lutea increased corneal thickness, tear volume, and size of the corneal cells, and reduced damage to the corneal cells. Furthermore, treatment of ARPE-19 human retinal pigmented epithelial cells with T. lutea reduced expression of the inflammatory factor, NF-κB, MAPK, and AKT. T. lutea may be used therapeutically to reduce the symptoms of DES.

Changes in retinal vessel and retinal layer thickness after cross-linking in keratoconus via swept-source OCT angiography.

To analyze the postoperative foveal avascular zone (FAZ) area, superficial capillary plexus (SCP), deep capillary plexus (DCP) vascular densities (VD), and retinal layers after cross-linking (CXL) for keratoconus treatment. Twenty-seven eyes with cross-linking treatment for keratoconus were included in the study. Foveal avascular zone (FAZ) area, SCP VD, DCP VD, and retinal layers were evaluated by using optical coherence tomography angiography (OCTA). OCTA measurements were made at preoperative, first week, and first and sixth months after the surgery. In addition, corneal topography measurements were also made. Although there was a decrease in corneal thickness in the follow-up of the patients, there was no significant difference in axial length and anterior chamber depth. There was no significant difference in full retinal thickness in the foveal and parafoveal areas. While there was a significant increase in retinal nerve fiber layer (RNFL) thickness in the foveal area (p = 0.032, p = 0.015, p = 0.017; preoperative values compared to first week, first month, and sixth month respectively), there was a decrease in ganglion cell layer (GCL) thickness in the parafoveal area in the postoperative sixth month (p = 0.028). There was no difference in FAZ measurements. In the parafoveal area, a decrease was observed in SCP VD in the sixth-month control (p = 0.019). There was a significant increase in DCP VD in the foveal area (p = 0.008, p = 0.043, p = 0.040). The preoperative mean CDVA (corrected distance visual acuity) was 0.37 ± 0.16 logMAR and postoperative sixth month mean CDVA was 0.39 ± 0.15. There was no significant difference in visual acuity(p = 0.71). Keratoconus patients successfully treated with CXL had significant changes in retinal layers and vessel density in the superficial and deep retinal plexus.

Association Between Central Corneal Thickness and Growth Parameters Following Preterm

Objective: To investigate central corneal thickness in prematurely born children and to evaluate the association between central corneal thickness and growth pattern during 3 months following preterm birth. Methods: In this prospective study, central corneal thickness, head circumference, body length and body weight measurements were performed in 32 infants at monthly intervals during the first 3 months following preterm birth. Central corneal thickness measurements were performed by using an ultrasonic pachymetry. Initial central corneal thickness measurements were performed 24 – 48 hours after delivery. The head circumference, body length and body weight measurements were performed within 24 hours following birth by a neonatologist. All measurements were carried out at 1st month, 2nd month and 3rd month in the same manner. Results: There were 18 female (56.2%) and 14 male (43.8%) infants. The mean gestational age and body weight at birth were 27.8 weeks and 1042±309.9 g, respectively. The mean head circumference and body length at birth were 26.2 cm and 36.3 cm, respectively. Mean central corneal thickness at birth was 666.03±92.6 µm. Central corneal thickness significantly decreased during the study period (p<0.001). Head circumference, body length and body weight showed significant increases following birth (p<0.001 for each). There was a significant negative correlation of central corneal thickness change with the body length change between 1st month and 2nd month (p<0.05). Conclusion:In this study, decrease of corneal thickness in prematurely born infants was found to be inversely correlated to body length alterations in early months of life. Key Words: Body length, Body weight, Central corneal thickness, Head circumference measurement, Premature

Hyperosmolar Eye Drops for Diurnal Corneal Edema in Fuchs’ Endothelial Dystrophy: A Double-Masked, Randomized Controlled Trial

The Eye Drops for Early Morning-Associated Swelling (EDEMAS) trial assessed the efficacy of hyperosmolar eye drops on corneal edema resolution. Double-masked, randomized controlled trial of hyperosmolar eye drops. Participants with Fuchs' dystrophy scheduled for Descemet membrane endothelial keratoplasty. One eye was randomized to hyperosmolar eye drops (treatment); the fellow eye was randomized to artificial tears (placebo). After baseline examination in the afternoon, corneas were examined using Scheimpflug tomography after eye opening in the morning. Participants received eye drops twice. Imaging was repeated every 30 minutes up to 4 hours. Decrease in central corneal thickness 1 hour after eye opening (primary end point), corneal thickness, subjective visual function, glare, visual acuity, and adverse events (AEs) (secondary end points). A total of 68 participants received the allocated intervention (59 eyes received treatment; 55 eyes received placebo). All eyes had stromal edema; none had epithelial edema. Corneal thickness was 626 μm in the treatment arm and 622 μm in the placebo arm after eye opening, indicating an early morning edema compared with baseline of+21 μm and+24 μm, respectively. Decrease in corneal thickness after 1 hour was-10.5 μm in the treatment arm (95% confidence interval [CI],-12.8 to-8.2) and-11.2 μm (95% CI,-13.6 to-8.9) in the placebo arm (between-arm difference, 0.7 μm, 95% CI,-2.0 to 3.5; P= 0.59), indicating no clinically relevant effect of hyperosmolar eye drops on early morning corneal edema. Results were not compatible with a relevant treatment effect on corneal thickness, visual acuity, and glare over the entire course of the study. Increase in subjective visual function was less rapid in the treatment arm than in the placebo arm. Adverse events, most commonly burning after eye drop application, were more common with treatment (30 eyes) than placebo (1 eye; risk difference, 49 percentage points; 95% CI, 36-62). In this double-masked, randomized controlled trial, resolution of early morning stromal edema was not accelerated by hyperosmolar eye drops, which more frequently caused AEs. These results are not compatible with a clinically relevant effect of hyperosmolar eye drops and do not support their routine use.

The Effect of Corneal Collagen Cross-Linking on Higher Order Aberrations in Keratoconus

Purpose: To assess the changes in ocular high order aberrations after collagen cross linking for keratoconus.&#x0D; Patients and Methods: This study included 30 eyes with confirmed KCN. Baseline evaluation focused on: UDVA and BSCVA using logMAR notation, MRSE, corneal topography using Orbscan IIZ and wave-front aberrometry using Zywave II. CXL was performed per ‘Dresden protocol’ through a 30-minutes exposure to 370 nm UVA with an irradiance of 3 mW/cm 2. Patients had comprehensive ophthalmic evaluation after 6 months with special attention to: UDVA, BSCVA, MRSE, corneal topography and wave-front aberrometry changes. &#x0D; Results: The mean age was 25.5±5.84 (20:31) years. After 6 months, there was a significant decrease in corneal thickness from 493.2± 24.17µ to 486.7±24.26µ (P&lt;0.05) and a significant decrease in K max from 47.4±1.17D to 46.1±1.17D (P&lt;0.05). BSCVA improved from preoperative value (0.00:0.5 logMAR (median 0.3)) to 6 months’ value (0.1:1.00 logMAR (median 0.2) (P &lt;0.05). Preoperative MRSE was -7.25: -0.5D (median -2.85D) and at 6 months was -6.25: -0.5D (median - 2.125D) (P&lt;0.05). A significant correlation was found at 6 months between changes in both BSCVA and: K max (P&lt;0.001), corneal thickness (P&lt;0.05), vertical coma (P&lt;0.001) and trefoil (P&lt;0.001). &#x0D; Conclusions: Improvement in HOA was detected after CXL for KCN. The changes in total, vertical coma and vertical trefoil aberrations were significantly correlated with postoperative improvement in BSCVA. Thus, improvement in HOA profile after CXL is one of the explanations of improvement in visual function after CXL in KCN.

Исследование биомеханических свойств роговицы на приборе CORVIS ST (Oculus, Германия) у пациентов с миопией и миопическим астигматизмом

Purpose. To evaluate the corneal biomechanical properties using the CORVIS ST device (Oculus, Germany) in patients with myopia and myopic astigmatism with intact cornea as well as in patients with myopia and myopic astigmatism who underwent excimer laser refractive surgery using femtolaser or microkeratome. Material and methods. Totally the study included 65 patients aged 18 years to 56 years with myopia and myopic astigmatism of various degrees were examined. They were scheduled for excimer laser refractive surgery after laser refractive surgery in different periods from 5 days to 5 years. Among the additional methods of examination, all patients were measured the biomechanical properties of the cornea using a CORVIS ST device (Oculus, Germany). Results. After excimer laser refractive surgery performing for myopia and myopic astigmatism correction, indicators of the corneal biomechanical properties, namely indicators describing stiffness and elasticity were changed, as well as IOP indicators. Conclusion. The biomechanical properties of the cornea, such as stiffness and elasticity, can be assessed using the CORVIS ST device (Oculus, Germany). After excimer laser vision correction of myopia and myopic astigmatism, corneal stiffness and elasticity decreases. IOP value in patients after excimer laser correction of myopia and myopic astigmatism decreases. It is associated with a decrease in corneal thickness but is not associated with a true decrease in IOP. Key words: biomechanical properties of the cornea, refractive surgery, excimer laser vision correction, femtolaser vision correction, myopia, myopic astigmatism.

Tissue Inhibitor of Metalloproteinase (TIMP) Peptidomimetic as an Adjunctive Therapy for Infectious Keratitis.

Matrix metalloproteinase 9 (MMP-9) has a key role in many biological processes, and while it is crucial for a normal immune response, excessive release of this enzyme can lead to severe tissue damage, as evidenced by proteolytic digestion and perforation of the cornea during infectious keratitis. Current medical management strategies for keratitis mostly focus on antibacterial effects, but largely neglect the role of excess MMP activity. Here, a cyclic tissue inhibitor of metalloproteinase (TIMP) peptidomimetic, which downregulated MMP-9 expression both at the mRNA and protein levels as well as MMP-9 activity in THP-1-derived macrophages, is reported. A similar downregulating effect could also be observed on α smooth muscle actin (α-SMA) expression in fibroblasts. Furthermore, the TIMP peptidomimetic reduced Pseudomonas aeruginosa-induced MMP-9 activity in an ex vivo porcine infectious keratitis model and histological examinations demonstrated that a decrease of corneal thickness, associated with keratitis progression, was inhibited upon peptidomimetic treatment. The presented approach to reduce MMP-9 activity thus holds great potential to decrease corneal tissue damage and improve the clinical success of current treatment strategies for infectious keratitis.

Crescent-shaped anterior lamellar keratoplasty as treatment of corneal perforation in peripheral ulcerative keratitis

Purpose: to raise awareness of potential severe ocular complications associated with autoimmune diseases and to describe the surgical technique of crescent-shaped anterior lamellar keratoplasty to treat a corneal perforation in peripheral ulcerative keratitis. Methods and Materials: Case report. Results: A female patient with 59 years old, with history of longstanding rheumatoid arthritis, presented with redness and photophobia in the right eye. As past ocular history, the patient had a severe keratoconjunctivitis sicca and a corneal ulcer in the right eye. Clinical examination revealed an epithelial defect with a significant inferior corneal thickness decrease. Topical steroids, antibiotics and a therapeutic contact lens were prescribed. One month later, a corneal perforation was observed and a crescent-shaped deep anterior lamellar keratoplasty was then performed. Conclusion: The clinical course of peripheral ulcerative keratitis depends on the associated systemic pathology, being essential a multidisciplinary approach by ophthalmologists and rheumatologists to allow systemic control of the autoimmune disease, avoiding possible complications such as eye perforation.

A modified technique of keratoleptynsis ("letter-box") for treatment of canine corneal edema associated with endothelial dysfunction.

To describe a modified keratoleptynsis procedure, as a method of preserving central corneal function, and evaluate the outcome in vision, reduction of corneal thickness and treatment of epithelial corneal ulcers in cases with endothelial cell dysfunction. Forty-four dogs (72 eyes) were affected by progressive corneal edema, with or without ulcerative keratitis. All patients were treated with a dorsal and ventral superficial keratectomy followed by conjunctival flaps, maintaining a clear central cornea. Corneal thickness measurements were obtained via ultrasound biomicroscopy. All eyes showed resolution of ocular discomfort postoperatively, with a median time to resolution of 35days. Two years post-surgery, vision had been lost in 2 of 29 eyes (7%). From the initial population, 23 dogs (39 eyes) had follow-up evaluations of corneal thickness. The mean central corneal thickness was 1359±251μm prior to surgery. Thickening of the central cornea was observed one week after surgery to 1559±263μm. Decreased corneal thickness was reported, at 1month, 4months, 10months and 2years postoperatively (1285±267μm, 1102±150μm, 1121±288μm, 1193±283μm, respectively). All eyes showed a similar trend of increasing and then decreasing corneal thickness. This surgical technique provided statistically significant reduction in central corneal thickness and sustained relief of ocular pain. Reduction in corneal thickness appeared to be maintained 2years post-surgery, and all patients remained comfortable. Superficial corneal pigmentation and fibrosis resulted in vision loss in two eyes.

A reliable animal model of corneal stromal opacity: Development and validation using in vivo imaging

PurposeTo validate an animal model of corneal stromal opacity by using objective vision-independent in vivo imaging metrics. MethodsThis was a prospective study, with two arms: (i) observational human arm which included 14 patients with healed unilateral ulcerative keratitis; and (ii) experimental rabbit arm, which included 6 New Zealand white rabbits. A 3-mm central wound was created in the left eye of the rabbits by manually removing 200–250 μm of the superficial stroma, followed by rotating-burr application. Both groups underwent photography, high-resolution anterior segment optical coherence tomography, and Scheimpflug imaging using similar diagnostic platforms and standardized image capturing protocols. Parameters studied were relative change in (i) corneal thickness; (ii) corneal epithelial: stromal (E:S) reflectivity ratio; (iii) corneal stromal light scattering using densitometry; and (iv) central corneal keratometry. ResultsIn the experimental arm, there was a significant decrease in corneal thickness (273 ± 51.3 vs. 407.3 ± 10.3 μm, p = 0.0038), E:S reflectivity ratio (0.71 ± 0.09 vs. 0.99 ± 0.06, p = 0.0018), and keratometry (40.4 ± 2.3 vs. 45.8 ± 0.9D, p = 0.0033) and increase in densitometry (54.2 ± 11.65 vs.18.7 ± 3.8 GSU, p = 0.0001) from baseline, which stabilized at 4 to 8-weeks post-wounding (p > 0.3632). At 8-weeks, the relative change from baseline in corneal thickness (28.4 ± 13.5% vs.22.4 ± 13%, p = 0.368), E:S reflectivity ratio (28.1 ± 11.5% vs. 30.6 ± 8.9%, p = 0.603), corneal densitometry (204.17 ± 97.3% vs. 304.9 ± 113.6%, p = 0.1113), and central corneal keratometry (13.6 ± 6.9% vs. 18.9 ± 7.4%, p = 0.1738) in rabbits was similar to human corneal scars. ConclusionThe animal model of corneal opacification was objectively comparable to human post-keratitis scars and can be valuable for in vivo evaluation of emerging therapies for corneal opacities.

Whole-Exome Sequencing Identifies Novel Compound Heterozygous ZNF469 Mutations in Two Siblings with Mild Brittle Cornea Syndrome

Connective tissue diseases, including osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS), exhibit a high degree of clinical and genetic heterogeneity. We report two sisters with blue sclerae, joint hypermobility and hearing loss. Whole-exome sequencing identified two compound heterozygous ZNF469 loss-of-function mutations due to a frameshift. Since these findings indicate the presence of brittle cornea syndrome (BCS), we performed ocular optical coherence tomography (OCT) and pachymetry, which revealed a moderate decrease in corneal thickness. While only one traumatic fracture was observed in each of the patients, a detailed skeletal assessment indicated no specific patterns of bone mass and microstructure reduction as well as normal bone turnover markers. Taken together, our findings point to a mild form of brittle cornea syndrome with a phenotype compatible with the extraskeletal features of OI but also with EDS.

Comparative Two-Photon Fluorescence Microscopy Analysis of Riboflavin Penetration in Two Different Solutions: Dextran and Hydroxypropyl Methylcellulose.

PurposeThis study compared riboflavin penetration in porcine corneas using two different solutions: dextran and hydroxypropyl methylcellulose (HPMC).MethodsPorcine corneas were de-swollen and after prepared in an artificial anterior chamber with balanced saline solution. The pressure was checked with a portable tonometer. We used 0.1% riboflavin in 20% dextran for 30 min or 0.1% riboflavin in 1% HPMC for 10 min. The fluorescence intensity in multiphoton microscopy was used to evaluate concentration into the cornea, and ultrasonic pachymetry was performed before and after using riboflavin.ResultsRiboflavin concentration up to 340 μm was higher in the HPMC group (p 0.146). From 340 microns to 500 μm, the concentration was higher in the dextran group (p 0.248). There was no statistically significant difference between the groups when considering all the corneal thickness studied (p 0.528). Pachymetric measurements in the group with dextran showed a 12.9% corneal thickness decrease after 30 min, while the HPMC group showed a 9.1% increase after 10 min.ConclusionWe concluded that 1% HPMC riboflavin for 10 min had the same level of safety when compared to the Dresden protocol with dextran riboflavin for 30 min. Ultrasonic pachymetry during corneal crosslinking has fundamental importance in controlling corneal hydration due to changes in thickness caused by different types of riboflavin. This study used different methods than previous studies to better simulate corneal physiological conditions and used 1% HPMC concentration which differs from previous studies performed with 1.1% HPMC.

Comparison of the Success Rate of Two Different Marking Techniques (F-Mark and Asymmetric Triangular Mark) to Orient the Donor Graft During Descemet Membrane Endothelial Keratoplasty.

We evaluated the effects of various graft-marking techniques on surgical results in patients undergoing Descemet membrane endothelial keratoplasty. In this single-center retrospective study, 65 eyes from 55 patients that had received various types of marking or no marking and that had been used for Descemet membrane endothelial keratoplasty endothelial graft preparation were included. Patients were divided into 3 groups according to the marking technique used: group I (F-marked graft; 17 eyes), group II (asymmetric triangle-marked graft; 12 eyes), and group III (unmarked graft; 36 eyes). The main outcome measurements were best-corrected visual acuity, endothelial cell density, central corneal thickness, postoperative complications, rebubbling, and secondary keratoplasty rates. In groups I, II, and III, rates of patients with 6-month best-corrected visual acuity ≥ 20/32 were 35.7%, 77.8%, and 71.9%, respectively (P = .04). The mean 6-month endothelial cell density decrease for each group was 43.3%, 48.8%, and 46.4%, respectively (P = .589), whereas the mean 6-month central corneal thickness decrease for each group was 7.7%, 15.8%, and 34.0%, respectively (P = .001). Rates of primary graft failure for groups I, II, and III were 35.3%, 8.3%, and 13.9%, respectively. Rebubbling was performed in 21.5% of eyes, and secondary keratoplasty was required in 29.2% of eyes. Although graft-marking techniques for Descemet membrane endothelial keratoplasty greatly facilitate graft positioning during surgery, both the potential toxic effects of alcohol on the endothelium when marking with gentian violet dye and the risk of graft detachment with asymmetric marking must be considered.