Increase In Corneal Thickness Research Articles

12562 Extraocular Muscle Enlargement With Proptosis In A Patient With Non Thyroidal Disease

Abstract Disclosure: S.S. Bantu: None. P.N. Kabir: None. A. Gondhi: None. T.B. Vaughan: None. Extraocular muscle enlargement with proptosis in a patient with Nonthyroidal disease Introduction: Majority of cases with extraocular muscle enlargement (EOME) is due to Graves’ disease, commonly in about 95% cases and another 5% make up other causes including inflammatory, neoplastic, vascular, infectious and acromegaly. We present a patient with sudden loss of vision, retroorbital pain with visual field deficits found to have EOME and subsequently a pituitary macroadenoma on imaging. Case: We present a 54-year-old male with history of hypertension, obstructive sleep apnea and morbid obesity who presented to us with complains of left sided vision loss. Patient was evaluated by ophthalmology and noted to have unilateral, left-sided, change in visual acuity. Physical exam was notable for macrognathia, skin tags, enlarged hands, excessive sweating. MRI brain revealed bilateral EOME with proptosis and a pituitary macroadenoma measuring 1.5x1.7x1.3cm, abutting the pre-chiasmatic left optic nerve. On biochemical evaluation he was noted to have elevated IGF1 of 979 confirming the diagnosis of acromegaly. ((hemoglobin A1C of 5.5%, prolactin 5.1, FT4 0.89, TSH 0.692, total testosterone 61, IGF1 level was 979)). He underwent transsphenoidal resection of the pituitary macroadenoma. Pathology showed sparsely granulated somatotroph adenoma. Discussion: Acromegaly has an incidence of 3-4 cases per million per year. The characteristics of the disease are due to chronic growth hormone hypersecretion resulting in the excessive growth of tissue due to the stimulation of insulin-like growth factor 1 (IGF-1). EOME with proptosis in acromegaly is seen rarely. Visual symptoms may manifest as visual field deficits due to compression of the optic pathway in 18-25% cases, increased intraocular pressure, increase in corneal thickness and a diffuse symmetrical enlargement of the extraocular muscles which cannot be distinguished from thyroid orbitopathy on imaging. The degree of enlargement appears to correlate with the duration of the disease rather than the levels of IGF1. EOME improves with the treatment of acromegaly. Although visual symptoms may be a rare presentation of acromegaly, if the clinical suspicion exists, one may consider obtaining an IGF-1 level to complete the evaluation of EOME if the thyroid levels are normal. Presentation: 6/3/2024

Pathogenesis of Fuchs endothelial corneal dystrophy, the fibrillar layer and individualized treatment

Fuchs endothelial corneal dystrophy (FECD) is agenetic and age-associated corneal disease characterized by an accelerated loss of corneal endothelial cells and an increased subendothelial deposition of extracellular matrix (ECM). Clinically, advanced disease leads to corneal edema with subsequent reduction in visual acuity. In the majority of patients with advanced FECD, afibrillar layer (FL) appears on the posterior corneal surface. This FL is mostly localized in the inferotemporal corneal quadrant, marks areas with significantly reduced endothelial cell density and increased corneal thickness in the sense of edema and can be visualized and measured using Scheimpflug backscatter analysis due to increased backscatter. FECD is currently the most common indication for corneal transplantation worldwide, usually in the form of Descemet membrane endothelial keratoplasty (DMEK). New treatment approaches include variations of DMEK surgery such as hemi- or quarter DMEK with individualized and smaller grafts or Descemet membrane stripping only (DSO). In the future, clinical imaging of the FL as aparticularly affected endothelial area could be important for FECD progression assessment and planning of surgical interventions. This article provides an overview of the current state of research on the clinical aspects, pathogenesis, fibrillar layer and individualized treatment of FECD.

Neuropeptide alpha-Melanocyte stimulating hormone preserves corneal endothelial morphology in a murine model of Fuchs dystrophy

Fuchs endothelial corneal dystrophy is a heterogenous disease with multifactorial etiology, and genetic, epigenetic, and exogenous factors contributing to its pathogenesis. DNA damage plays a significant role, with ultraviolet-A (UV-A) emerging as a key contributing factor. We investigate the potential application of neuropeptide α-melanocyte stimulating hormone (α-MSH) in mitigating oxidative stress induced endothelial damage. First, we examined the effects of α-MSH on a cultured human corneal endothelial cell line (HCEnC-21T) exposed to hydrogen peroxide (H2O2) induced oxidative DNA damage. We performed immunofluorescence and flow cytometry to assess DNA damage and cell death in the cultured cells. Additionally, we used an established mouse model that utilizes ultraviolet light to induce corneal endothelial cell damage resulting in decreased CEnC number, increased cell size variability, and decreased percentage of hexagonal cells. This endothelial decompensation leads to an increase in corneal thickness. Following UV-A exposure, the mice were systemically treated with α-MSH, either immediately after exposure (early treatment) or beginning two weeks post-exposure (delayed treatment). To evaluate treatment efficacy, we analyzed CEnC density and morphology using in vivo confocal microscopy, and central corneal thickness using anterior segment optical coherence tomography. Our findings demonstrated that α-MSH treatment effectively protects HCEnC-21T from free-radical induced oxidative DNA damage and subsequent cell death. In vivo, α-MSH treatment, mitigated the loss of CEnC density, deterioration of cell morphology and suppression of the resultant corneal swelling. These results underline the potential application of α-MSH as a therapeutic agent for mitigating corneal endothelial damage.

Injectable cross-linked hyaluronic acid hydrogels with epigallocatechin gallate loading as vitreous substitutes

Hyaluronic acid (HA) serves as a vitreous substitute owing to its ability to mimic the physical functions of native vitreous humor. However, pure HA hydrogels alone do not provide sufficient protection against potential inflammatory risks following vitrectomy. In this study, HA was crosslinked with 1,4-butanediol diglycidyl ether (BDDE) to form HA hydrogels (HB). Subsequently, the anti-inflammatory agent epigallocatechin gallate (EGCG) was added to the hydrogel (HBE) for ophthalmic applications as a vitreous substitute. The characterization results indicated the successful preparation of HB with transparency, refractive index, and osmolality similar to those of native vitreous humor, and with good injectability. The anti-inflammatory ability of HBE was also confirmed by the reduced expression of inflammatory genes in retinal pigment epithelial cells treated with HBE compared with those treated with HB. In a New Zealand white rabbit model undergoing vitreous substitution treatment, HBE 50 (EGCG 50 μM addition) exhibited positive results at 28 days post-surgery. These outcomes included restored intraocular pressure, improved electroretinogram responses, minimal increase in corneal thickness, and no inflammation during histological examination. This study demonstrated the potential of an injectable HA-BDDE cross-linked hydrogel containing EGCG as a vitreous substitute for vitrectomy applications, offering prolonged degradation time and anti-inflammatory effects postoperatively.

Diesel exhaust exposure induced squamous metaplasia of corneal epithelium via yes-associated protein activation

Atmospheric pollution has been demonstrated to be associated with ocular surface diseases characterized by corneal epithelial damage, including impaired barrier function and squamous metaplasia. However, the specific mechanisms underlying the impact of atmospheric pollution on corneal damage are still unknow. To address this gap in knowledge, we conducted a study using a whole-body exposure system to investigate the detrimental effects of traffic-related air pollution, specifically diesel exhaust (DE), on corneal epithelium in C57BL/6 mice over a 28-day period. Following DE exposure, the pathological alterations in corneal epithelium, including significant increase in corneal thickness and epithelial stratification, were observed in mice. Additionally, exposure to DE was also shown to disrupt the barrier functions of corneal epithelium, leading to excessive proliferation of basal cells and even causing squamous metaplasia in corneal epithelium. Further studies have found that the activation of yes-associated protein (YAP), characterized by nuclear translocation, may play a significant role in DE-induced corneal squamous metaplasia. In vitro assays confirmed that DE exposure triggered the YAP/β-catenin pathway, resulting in squamous metaplasia and destruction of barrier functions. These findings provide the preliminary evidence that YAP activation is one of the mechanisms of the damage to corneal epithelium caused by traffic-related air pollution. These findings contribute to the knowledge base for promoting eye health in the context of atmospheric pollution.

Recurrence Characteristics on Optical Coherence Tomography and Treatments of Reis-Bücklers Corneal Dystrophy After Phototherapeutic Keratectomy or Penetrating Keratoplasty

PurposeTo evaluate the recurrence characteristics on optical coherence tomography and clinical outcomes after phototherapeutic keratectomy (PTK) or penetrating keratoplasty (PKP) in patients with Reis-Bücklers corneal dystrophy (RBCD). DesignRetrospective interventional case series. MethodsSeventeen patients with RBCD (31 eyes, including six surgery-naïve eyes and 25 surgical eyes) received 44 surgical interventions from 1996 through 2022. PTK or PKP was performed as the initial surgical procedure. Significant recurrence was determined when best spectacle-corrected visual acuity decreased at least two lines with increased opacity in the superficial cornea. Repeated PTK or PTK on the corneal graft (CG-PTK) was considered if patients could not endure poor vision due to significant recurrence. Recurrence depth and annual increase in thickness of the central cornea and subepithelial deposits were assessed by anterior segment optical coherence tomography. ResultsThe mean follow-up time was 12.8±8.5 years (range, 2.0–25.5 years). The mean logMAR best spectacle-corrected visual acuity improved from 1.24±0.48 preoperatively to 0.27±0.09 postoperatively in the initial PTK group (13 eyes, P<0.001), from 1.84±0.69 to 0.40±0.13 in the PKP group (12 eyes, P<0.001), from 1.04±0.46 to 0.30±0.07 in the repeated PTK group (12 times in 7 eyes, P<0.001), and from 1.29±0.43 to 0.39±0.11 in the CG-PTK group (7 times in 5 eyes, P=0.001). The median significant recurrence time was 27 months (95% confidence interval 23.9-30.1), 96 months (84.1-107.9), 31 months (28.8-33.1), and 24 months (19.8-28.2), respectively (P<0.001). The depth of superficial deposits located between the epithelium and the anterior stroma was approximately 115μm (85-159μm). The annual thickening of subepithelial deposits was 14±2μm after initial PTK, 7±3μm after PKP, 14±3μm after repeated PTK, and 30±11μm after CG-PTK, compared to 4±2μm in surgery-naïve eyes (P=0.002, 0.515, 0.002, <0.001). The thickness of the central cornea increased by 15±2μm, 7±2μm, 15±3μm, and 31±10μm per year in the four surgery groups, respectively, compared to 5±2μm in surgery-naïve eyes (P=0.001, 0.469, 0.001, <0.001). ConclusionsBetter visual acuity can be achieved after PTK than PKP for treatment of RBCD. The annual thickening of subepithelial deposits may approximate an increase in central corneal thickness. The superficial distribution of subepithelial deposits makes it feasible to perform repeated PTK, even on the corneal allograft, for recurrent RBCD.

Comparison of corneal endothelial cell loss in FLACS: impact on endothelial cells in different regions.

To compare changes in corneal endothelial parameters after femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification surgery (CPS) in different corneal regions. Chang Gung Memorial Hospital, Linkou, Taiwan. Single-center, retrospective. Before and 1, 3, and 6 months postoperatively, specular microscopy was performed to measure endothelial cell density (ECD), corneal thickness, hexagonal cell rate (Hex), and coefficient of variation (CoV). Position 1 referred to the central cornea, position 2 was nearest to the main wound, and position 3 was at the peripheral zone diagonal to the main wound. This study analyzed 96 eyes in the FLACS group and 110 eyes in the CPS group. Preoperatively, position 1 had lower ECD and CoV and higher Hex compared with the peripheral regions. FLACS patients had a significantly less phacoemulsification time and cumulative dissipated energy. At 1 month, FLACS patients showed a significantly smaller increase in corneal thickness at positions 1 and 2. At 3 months, FLACS patients had lower endothelial cell loss (ECL) at positions 1 and 3. ECL remained lower in FLACS patients at 6 months. The highest ECL was observed at position 2 in both groups and was progressive up to 6 months. After phacoemulsification, ECL varied in different corneal regions. At 3 months, the FLACS group exhibited significantly less ECL at the central cornea; however, the continued ECL at 6 months near the main wound suggested ongoing endothelial remodeling in the region.

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.

Blast injury: Impact to the cornea

Visual disorders are common even after mild traumatic brain injury (mTBI) or blast exposure. The cost of blast-induced vision loss in civilians, military personnel, and veterans is significant. The visual consequences of blasts associated with TBI are elusive. Active military personnel and veterans report various ocular pathologies including corneal disorders post-combat blasts. The wars and conflicts in Afghanistan, Iraq, Syria, and Ukraine have significantly increased the number of corneal and other ocular disorders among military personnel and veterans. Binocular vision, visual fields, and other visual functions could be impaired following blast-mediated TBI. Blast-associated injuries can cause visual disturbances, binocular system problems, and visual loss. About 25% of veterans exposed to blasts report corneal injury. Blast exposure induces corneal edema, corneal opacity, increased corneal thickness, damage of corneal epithelium, corneal abrasions, and stromal and endothelial abnormality including altered endothelial density, immune cell infiltration, corneal neovascularization, Descemet membrane rupture, and increased pain mediators in animal models and the blast-exposed military personnel including veterans. Immune response exacerbates blast-induced ocular injury. TBI is associated with dry eyes and pain in veterans. Subjects exposed to blasts that cause TBI should undergo immediate clinical visual and ocular examinations. Delayed visual care may lead to progressive vision loss, lengthening/impairing rehabilitation and ultimately may lead to permanent vision problems and blindness. Open-field blast exposure could induce corneal injuries and immune responses in the cornea. Further studies are warranted to understand corneal pathology after blast exposure. A review of current advancements in blast-induced corneal injury will help elucidate novel targets for potential therapeutic options. This review discusses the impact of blast exposure-associated corneal disorders.

Characterization of a Novel Mouse Model for Fuchs Endothelial Corneal Dystrophy.

Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention. To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay. The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function. Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.

Chemical (Alkali) Burn-Induced Neurotrophic Keratitis Model in New Zealand Rabbit Investigated Using Medical Clinical Readouts and In Vivo Confocal Microscopy (IVCM).

Chemical eye injury is an acute emergency that can result in vision loss. Neurotrophic keratitis (NK) is the most common long-term manifestation of chemical injury. NK due to alkali burn affects ocular surface health and is one of its most common causes. Here, we established a rabbit model of corneal alkali burns to evaluate the severity of NK-associated changes. Alkali burns were induced in NZ rabbits by treating the cornea with (i) a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (Mild NK) and (ii) trephination using a guarded trephine (5 mm diameter and 150-micron depth), followed by alkali burn, with a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (a severe form of NK). Immediately after, the cornea was rinsed with 10 mL of normal saline to remove traces of NaOH. Clinical features were evaluated on Day 0, Day 1, Day 7, Day 15, and Day 21 post-alkali burn using a slit lamp, Pentacam, and anterior segment optical coherence tomography (AS-OCT). NK-like changes in epithelium, sub-basal nerve plexus, and stroma were observed using in vivo confocal microscopy (IVCM), and corneal sensation were measured using an aesthesiometer post alkali injury. After 21 days, pro-inflammatory cytokines were evaluated for inflammation through ELISA. Trephination followed by alkali burn resulted in the loss of epithelial layers (manifested using fluorescein stain), extensive edema, and increased corneal thickness (550 µm compared to 380 µm thickness of control) evaluated through AS-OCT and increased opacity score in alkali-treated rabbit (80 compared to 16 controls). IVCM images showed complete loss of nerve fibers, which failed to regenerate over 30 days, and loss of corneal sensation-conditions associated with NK. Cytokines evaluation of IL6, VEGF, and MMP9 indicated an increased angiogenic and pro-inflammatory milieu compared to the milder form of NK and the control. Using clinical parameters, we demonstrated that the alkali-treated rabbit model depicts features of NK. Using IVCM in the NaOH burn animal model, we demonstrated a complete loss of nerve fibers with poor self-healing capability associated with sub-basal nerve degeneration and compromised corneal sensation. This pre-clinical rabbit model has implications for future pre-clinical research in neurotrophic keratitis.

Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect

Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 μm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 μm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 μm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 μm and light-room ARA at 750 μm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

Scheimpflug Tomography as a Predictor of Corneal Edema After Phacoemulsification in Fuchs Endothelial Corneal Dystrophy.

To determine if Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict the occurrence of corneal edema following uneventful phacoemulsification surgery in Fuchs endothelial corneal dystrophy (FECD). Observational prospective case-control study. Fifty FECD eyes (50 patients) with visually significant cataract: 25 with subclinical corneal edema (SCE) versus 25 without SCE. Preoperatively, FECD was clinically assessed, and only patients devoid of clinical corneal edema were enrolled. Utilizing the Mayo Clinic classification for subclinical corneal edema (SCE), eligible FECD eyes were stratified based on Scheimpflug imaging pachymetry map and posterior elevation map characteristics, including loss of regular isopachs, displacement of the cornea's thinnest point, and the presence of posterior surface depression, into two groups: Group A representing FECD with SCE, and Group B: FECD without SCE. One week postoperatively, clinical and tomographic evaluation was performed. Regression analysis was conducted to evaluate predictors of corneal edema after uneventful phacoemulsification surgery in both groups. All patients were successfully imaged before and 1 week after surgery. Visual acuity was significantly improved in both groups (P < 0.001). No postoperative clinical edema was observed in Group B, while 23 (92%) had mild edema and 2 (8%) had moderate edema in Group A. Both groups showed a significant increase in postoperative central corneal thickness (CCT) and thinnest corneal thickness (TCT) (both P < 0.001). Compared to Group B, Group A showed a significant central flattening of the anterior corneal surface (P = 0.007 and P = 0.04 for K1 and K2 respectively), and a significant increase in the postoperative posterior surface depression. Multivariate analysis showed that 94% of postoperative corneal edema could be predicted by the presence of preoperative posterior surface depression (P = 0.04, ARR = 5.8 (1.89-35.7)). Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict corneal edema after uneventful phacoemulsification surgery in FECD with subclinical corneal edema.

Intraocular pressure and its determinants in a very old population. The ural very old study

Aims/Purpose: To assess the distribution of intraocular pressure (IOP) and its determinants in a very old population.Methods: The population‐based Ural Very Old Study (UVOS) was performed in a rural and urban region of Bashkortostan/Russia and consisted of 1526 (81.1%) out of 1882 eligible individuals aged 85+ years. As part of a series of medical and ophthalmological examinations, we measured IOP by non‐contact tonometry.Results: The study included 1042 (68.3%) individuals with available IOP readings (mean age:88.1 ± 2.7 years). After excluding individuals with anti‐glaucomatous therapy, mean IOP was 14.5 ± 5.1 mmHg (median:14 mmHg; 95%CI:8,25) with a right‐sided skewed distribution. In multivariable analysis, higher IOP was associated (correlation coefficient r:0.38) with female sex (beta:0.13; p = 0.002), thinner central cornea thickness (beta:0.23; p &lt; 0.001), higher systolic blood pressure (beta:0.13; p = 0.006), higher estimated cerebrospinal fluid pressure (CSFP) (beta:0.11; p = 0.04), longer axial length (beta:0.09; p = 0.02), and status after cataract surgery (beta:‐0.17; p &lt; 0.001). In that model, the IOP measurements increased by 0.02 mmHg (95%CI:0.01,0.03) for each increase in systolic blood pressure by 1 mmHg, by 0.11 mmHg (95%CI:0.004,0.22) for each increase in estimated CSFP by 1 mmHg, by 0.2 mmHg (95%CI:0.1,0.3) for each central corneal thickness increase by 10 μm, and by 0.31 mmHg (95%CI:0.05,0.59) for each axial length increase by 1 mm. It decreased by 1.13 mmHg (95%CI:0.54,1.72) with cataract surgery.Conclusions: In this study population aged 85 + years, corneal thickness‐adjusted IOP‐readings increased with higher blood pressure and estimated CSFP and longer axial length, and it decreased with cataract surgery.

Impact of flight and equivalent short-term high-altitude exposure on ocular structures and function.

Exposure to high-altitude conditions during flight or similar activities affects many aspects of visual function, which is critical not only for flight safety but for any altitude-related activity. We aimed to summarize the available literature pertaining to ocular changes during flight or equivalent short-term high-altitude exposure (e.g., hypobaric chamber, effortless ascent lasting ≤ 24 h) and to highlight future research priorities. Using the PubMed/MEDLINE and Web of Science/ISI Web of Knowledge databases with structured search syntax, we conducted a systematic review of the literature spanning a 40-year period (January 1, 1983, to October 10, 2023). Articles pertaining to ocular changes during flight or flight-equivalent exposure to altitude were retrieved. The reference lists of retrieved studies were also searched, and citations of these references were included in the results. Of 875 relevant PubMed and ISI publications, 122 qualified for inclusion and 20 more were retrieved from the reference lists of initially selected records, for a total of 142 articles. Reported anterior segment changes included deterioration in tear film stability and increased dry eye incidence, increased corneal thickness, discomfort and bubble formation in contact lens users, refraction changes in individuals with prior refractive surgery, decreased intraocular pressure, and alterations in pupillary reaction, contrast sensitivity, and visual fields. Photoreceptor-visual pathway changes included alterations in both photoreceptors and neuro-transduction, as evidenced in dark adaptation, macular recovery time, reduction in visual field sensitivity, and optic neuritis (likely an element of decompression sickness). Retinochoroidal changes included increases in retinal vessel caliber, retinal blood flow, and choroidal thickness; central serous chorioretinopathy; and retinal vascular events (non-arteritic ischemic optic neuropathy, high-altitude retinopathy, and retinal vein occlusion). The effect of short-term high-altitude exposure on the eye is, in itself, a difficult area to study. Although serious impairment of visual acuity appears to be rare, ocular changes, including tear film stability, contact lens wear, central corneal thickness, intraocular pressure, contrast sensitivity, stability of refractive surgeries, retinal vessels, visual fields, and macula recovery time, should be considered in civilian aviators. Our report provides guidance to climbers and lowlanders traveling to altitude if they have pre-existing ocular conditions or if they experience visual symptoms while at altitude. However, key outcomes have been contradictory and comprehensive studies are scarce, especially those pertaining to the choroid and retina. Such studies could not only deepen our understanding of high-altitude ocular pathophysiology, but could also offer valuable information and treatment possibilities for a constellation of other vision-threatening diseases.

Evaluation of Corneal Topography Changes Following Deep Anterior Lamellar Keratoplasty in Patients with Keratoconus

Background. The aim of this study is to evaluate the morphologic changes of the cornea and anterior chamber by using corneal topography (CT) in patients undergoing deep anterior lamellar keratoplasty (DALK) due to keratoconus. Patients and methods. This observational case-control study included total 53 eyes of 53 patients with keratoconus and underwent DALK surgery. All patients were evaluated preoperatively and 3 months after suture removal with CT. In CT, anterior chamber depth (ACD), iridocorneal angle (ICA), anterior chamber volume (ACV), central corneal thickness (CCT), maximum keratometric value (Kmax), flattest simulated meridian keratometry (SimK1), steepest simulated meridian keratometry (SimK2) and simulated keratometry average (SimKavg) results were compared before and after DALK surgery. Results. A significant increase was observed in CCT values after DALK surgery (p &lt; 0.001). Patients showed statistically significant decrease in Kmax, SimK1, SimK2 and SimKavg values (p &lt; 0.001 for all). Postoperative ACD and ACV values were significantly lower (p &lt; 0.001). The ICA values showed no significant difference (p = 0.183) between preoperative and postoperative values (49,95 ± 5,85 and 46,30 ± 11,33 respectively). Conclusion. We determined a dramatic decrease in keratometric values, ACD and ACV values and an increase of corneal thickness after DALK surgery. Although DALK can be performed without interfering with the anterior chamber, has a significant effect in anterior chamber.

Endoilluminator-assisted management of acute hydrops in pellucid marginal corneal degeneration (PMCD) with compression sutures and intracameral perfluropropane (C3F8)

In this case, a male in his 30s presented to the clinic with blurring of vision, sudden whiteness, and pain in the left eye for 10 days. All preliminary examinations were recorded. He was a known case of Pellucid marginal corneal degeneration (PMCD). Clinical examination revealed corneal edema due to acute hydrops. Anterior segment optical coherence tomography (OCT) showed increased corneal thickness and a large descemets detachment. Endoilluminator-assisted compression sutures were placed along with intracameral C3F8 gas. As the tear was large, a 10-0 prolene suture was used instead of the conventional 10-0 nylon. This is the first case in literature in which acute hydrops in PMCD was managed with compression sutures (10-0 prolene) along with the injection of intracameral perfluropropane (C3F8) with the help of intraoperative use of endoilluminator.

Long-Term Real-World Outcomes of Corneal Changes in Proliferative Diabetic Retinopathy: Panretinal Photocoagulation vs. Intravitreal Conbercept

PurposeTo compare long-term real-world outcomes of corneal thickness (CT) alterations in proliferative diabetic retinopathy (PDR) patients treated with panretinal photocoagulation (PRP) and intravitreal conbercept (IVC). MethodsThis retrospective study included 69 eyes of 69 patients with PDR (42 PRP and 27 IVC). Full corneal thickness (FCT), corneal epithelial thickness (CET) and corneal stromal thickness (CST) measured by anterior segment optical coherence tomography at baseline were compared between groups. These CT changes at last follow-up from baseline were also compared between groups and within each group. ResultsDuring a mean follow-up of more than two years, the IVC group demonstrated a significantly increased corneal thickness from baseline compared to the PRP group in some areas (PRP vs. IVC: FCT 0-2 mm: -0.59 ± 9.31 vs. 5.59 ± 9.23 μm, p = 0.009; CST 0-2 mm: -2.05 ± 8.79 vs. 3.48 ± 7.52 μm, p = 0.015; CST 2-5 mm: -1.78 ± 13.27 vs. 5.68 ± 14.53 μm, p = 0.046). In within-group comparisons, a significantly increased FCT from baseline was found in the 0-2 mm area in the IVC group (p = 0.004), but no significant change was observed in the PRP group (p = 0.691). For CET changes, a significantly increased CT was observed in the 0-2 mm, 2-5 mm and 5-7 mm areas in both groups respectively (all p < 0.05). Regarding CST, an increased CT was found in the 0-2 mm area in the IVC group (p = 0.037), while a decreased trend was observed in 0-2 mm and 2-5 mm areas in the PRP group (all p > 0.05). ConclusionWhen using PRP or IVC in the long-term management of PDR, CT changes should be considered. This may provide evidence for corneal protection during PDR treatment.

The Effect of Artificial Tear Treatment on Central Corneal Thickness in Dry Eyes

Objective: To evaluate the role of artificial tear treatment on central corneal thickness in patients with dry eyes coming to a tertiary care eye hospital. Study Design: Quasi-experimental study. Place and Duration of Study: Tertiary Care Eye Center, Armed Forces Institute of Ophthalmology, Rawalpindi Pakistan, from May to Nov 2022. Methodology: The study included central corneal thickness of 210 eyes (n=210) of 110 patients with dry eye disease measured before and after treatment with continuous use of artificial tear drops one month apart, patients were diagnosed on the presence of symptoms such as burning, dryness, pain, irritation, grittiness followed by slit lamp examination for marginal tear meniscus(&lt;0.25mm) or absent, tear film BUT of &lt;10 seconds , Schrimer test 2 of &lt;6mm after 5 minutes and ocular surface staining score of &gt;1 with fluorescein. Central corneal thickness was measured using corneal topography (Galleli G6 Ziemer). Results: A total of two hundred and twenty eyes of 110 individuals having dry eyes were included in our study. Median CCT before treatment with artificial tears was 522(75)µm while median CCT after 1 month treatment with artificial tears was 547(22.25)µm this showed a percentage increase of 3.79% in central corneal thickness after one month treatment with artificial tears (p-value &lt;0.001) therefore treatment with artificial tears was significantly associated with an increase in central corneal thickness in dry eye disease. Conclusion: Central corneal thickness is substantially related to dry eyes.

Anterior segment optical coherence tomography in pediatric ocular pathology: imaging study of 115 eyes

ABSTRACT Objective To assess the pediatric anterior segment characteristics in ocular pathology using spectral domain optical coherence tomography (SD-OCT). Methods This case series follows 115 eyes of 78 children (2–17 years) with anterior segment pathology in an academic facility. The anterior segment OCT (AS-OCT) analysis was done using the Optopol Revo 80 high-resolution SD-OCT using an imaging adapter. All pathological features visible on imaging were observed, studied, tabulated, and analyzed. Results The average age was 11.84 years, with 44 males and 34 females. The primary clinical diagnosis was cataract in 40 (34.8%) eyes, followed by corneal disease in 28 (24.3%) eyes, glaucoma in 18 (15.7%) eyes, and trauma in 15 (13%) eyes. Systemic diseases were associated with 20.9% of the cases. The commonest imaging pathology observed was lens opacification in 43 (37.4%), increased reflectivity of the cornea in 31 (28.2%), corneal stromal thinning in 34 (29.6%), increased corneal thickness in 28 (24.3%), a shallow anterior chamber in 17 (14.8%), and cells in the anterior chamber in 18 (15.7%) eyes, along with a multitude of other findings. Conclusion This study demonstrates that anterior segment OCT is a useful non-contact technique for the detailed anatomic and pathologic assessment of pediatric ocular diseases.