Corneal Volume Research Articles

Abnormal corneal nerve morphology and brain volume in patients with schizophrenia

Neurodevelopmental and neurodegenerative pathology occur in Schizophrenia. This study compared the utility of corneal confocal microscopy (CCM), an ophthalmic imaging technique with MRI brain volumetry in quantifying neuronal pathology and its relationship to cognitive dysfunction and symptom severity in schizophrenia. Thirty-six subjects with schizophrenia and 26 controls underwent assessment of cognitive function, symptom severity, CCM and MRI brain volumetry. Subjects with schizophrenia had lower cognitive function (P ≤ 0.01), corneal nerve fiber density (CNFD), length (CNFL), branch density (CNBD), CNBD:CNFD ratio (P < 0.0001) and cingulate gyrus volume (P < 0.05) but comparable volume of whole brain (P = 0.61), cortical gray matter (P = 0.99), ventricle (P = 0.47), hippocampus (P = 0.10) and amygdala (P = 0.68). Corneal nerve measures and cingulate gyrus volume showed no association with symptom severity (P = 0.35–0.86 and P = 0.50) or cognitive function (P = 0.35–0.86 and P = 0.49). Corneal nerve measures were not associated with metabolic syndrome (P = 0.61–0.64) or diabetes (P = 0.057–0.54). The area under the ROC curve distinguishing subjects with schizophrenia from controls was 88% for CNFL, 84% for CNBD and CNBD:CNFD ratio, 79% for CNFD and 73% for the cingulate gyrus volume. This study has identified a reduction in corneal nerve fibers and cingulate gyrus volume in schizophrenia, but no association with symptom severity or cognitive dysfunction. Corneal nerve loss identified using CCM may act as a rapid non-invasive surrogate marker of neurodegeneration in patients with schizophrenia.

Central corneal thickness and its determinants in a geriatric population: a population-based study.

To determine the distribution of central corneal thickness (CCT) and its determinants in an Iranian geriatric population. This population-based study was conducted in 2019 in Tehran, the capital of Iran, using stratified multistage random cluster sampling. The study population was all residents ≥60 years of age. First, preliminary optometric and ocular health examinations were performed including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, anterior and posterior segment examination. The study participants then underwent corneal imaging using Pentacam HR. Out of 3791 invitees, 3310 participated in this study (response rate: 87.3%). The mean CCT and apex corneal thicknesses were 528 µ (95% CI: 526-529) and 529 µ (95% CI: 527-530), respectively. The highest and lowest mean corneal thickness was related to the superior (620 µ: 95% CI: 618-622) and the temporal (591 µ: 95% CI: 590-592) paracentral points, respectively. According to the multiple linear regression model, the CCT was significantly inversely related to keratometry readings (K1 and K2) and had a statistically significant direct relationship with intraocular pressure (IOP), corneal eccentricity (ECC), and corneal volume (CV) (all p values <0.05). The CCT was significantly higher in diabetic patients (p = 0.043). The CCT values in the geriatric Iranian population were lower than the values reported in most previous studies. The CCT is mostly influenced by IOP and corneal parameters (curvature, shape factor, and volume) and is not affected by demographic factors, refractive error, and ocular biometric components.

The short-term effects of intravitreal bevacizumab injection on intraocular pressure, cornea, iridocorneal angle, and anterior chamber.

Transient increase in intraocular pressure (IOP), changes in anterior chamber parameters, and changes in aqueous humor dynamics may occur after intravitreal injections because of intravitreal volume changes. In this observational study, we investigated the early effects of intravitreal bevacizumab (IVB) injection on IOP, central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), and iridocorneal angle (ICA). The patients who had one single-dose IVB (2.5 mg/0.1 mL) injection were included in the study. The patients underwent IOP, CCT, CV, ACD, and ICA measurements before and 1 h and 1 day after the injection. Pre-injection and post-injection values were compared. Forty-two eyes of 42 patients were included in the study, and the mean age of patients was 60.1 ± 7.4 years. The mean IOP measurements before and after injection at 1 h and day 1 were 15 ± 2.4, 17.4 ± 2.4, and 14.7 ± 2.3, respectively. The mean IOP, CCT, and CV values 1 h after injection were significantly higher than pre-injection values (p < 0.05, p < 0.05, and p = 0.02, respectively). Conversely, mean ACD and ICA values 1 h after injection were significantly lower than pre-injection values (p = 0.01 for both). There were no statistically significant differences on the first day after injection for all parameters. IVB (2.5 mg/0.1 mL) injection causes transient increases in IOP and transient decreases in ACD and ICA at the first hour after injection. Related to elevation in IOP, CCT and CV may increase transiently. These changes return to baseline values on the first day after injection.

Use of the corneal bioreactor to evaluate the anti‐edema effect and the ulcer healing rate between two commercial hyperosmotic eye drops: ODM5 and Muro 128

AbstractPurposeThe corneal bioreactor (BR) in our laboratory, with an intraocular pressure (IOP) of 21 mmHg and the renewal of the culture medium, allows to maintain the homeostasis of the 3 layers of the cornea. We showed that an IOP reduced to 10 mmHg allowed to simulate a corneal edema (760 ± 57 µm) with a healthy epithelium.AimTo compare 2 hyperosmolar eye drops in the evolution of corneal deturgescence and epithelial ulcer healing: ODM5 composed mainly of NaCl 5% and hyaluronic acid (Horus Pharma, Saint‐Laurent‐du‐Var, France) and Muro 128 composed mainly of NaCl 5% and various excipients (Bausch+Lomb, Bridgewater, NJ)MethodsBeforehand, 3 pairs of human corneas were preserved for 2 weeks in the BR filled with CorneaMax (Eurobio, France), with a pressure maintained at 10 mmHg. A central epithelial ulcer of 6.64 ± 0.04 mm in diameter was made (D0). Each cornea received a drop of Muro 128 or ODM5 four times a day. Corneal central volume measurement (Casia 1, Tomey) was performed daily at the beginning and end of the day. Ulcer healing was monitored daily by fluorescein labelling and quantified by image analysis (Fiji) taken with a macroscope. At D14, the corneas were removed and fixed for immunostaining of E‐Cad (cell architecture), Zo‐1 (tight junctions), MUC16 (mucins), K3K12 (cell maturity) and for histology (Saffron Eosin Hemathein).ResultsMean daily volume loss was comparable: 2.43 ± 1.55 mm3 with ODM5 vs. 2.18 ± 1.71 mm3 with Muro 128 (p = 0.698 3). Corneal ulcers in all 3 pairs healed at D4, D5, D5 with ODM5 vs. D5, D13, and 1 cornea never healed with Muro 128. In IHC and histology, the epithelium was of better quality with ODM5.ConclusionsThe efficacy of the 2 eye drops is comparable. Epithelial preservation is partly better with ODM5, possibly related to the presence of hyaluronic acid.

Corneal Biometric Features and Their Association With Axial Length in High Myopia

To characterize the morphologic features of corneal parameters and their correlation with axial length (AL) elongation in patients with high axial myopia. Cross-sectional comparative study. A total of 299 eyes with high myopia (299 patients) and 266 eyes of age- and sex-matched control subjects (266 patients) were examined by anterior segment swept-source optical coherence tomography (SS-OCT) and an IOL Master. Central corneal thickness (CCT), thinnest corneal thickness (TCT), corneal volume (CV), and anterior corneal curvature (CC), posterior CC, and total CC were obtained, and their correlation with AL was investigated using multiple linear regression model. The CCT, TCT, CV, and anterior, posterior, and total CC of patients with high myopia were smaller than those of the control subjects. The CCT, TCT, and CV had a continuous downward trend with AL. However, CC decreased rapidly with AL when AL was <26 mm and the slope decreased when AL was 26 to 28 mm. This linear association was absent when AL was >28 mm. Multiple linear regression showed that the CCT (β=-1.98, P=.007), TCT (β=-1.63, P=.019), and CV (β=-0.13, P=.001) were associated with AL. Anterior, posterior, and total CCs were negatively associated with AL when AL was <26 mm (all P < .001) and when AL was between 26 and 28 mm (all P < .05). CC decreases may serve as a refractive compensation on myopia when AL is <28 mm. However, this effect does not exist when AL is >28 mm. Consideration should be given to the special distribution of cornea curvature for IOL calculations in subjects with high myopia.

Non-invasive evaluation of meibomian gland morphology and tear film and anterior segment parameters in women with polycystic ovarian syndrome

PurposeTo compare the meibomian glands (MG), non-invasive tear film break-up time (NITBUT), and corneal and anterior segment measurements in patients with polycystic ovary syndrome and healthy women. MethodsThe study included 66 polycystic ovarian syndrome (PCOS) patients and 42 healthy volunteers aged 18–35 years. The first and average NITBUT, MG loss, mean keratometry (Km), central (CCT) and thinnest (TCT) corneal thicknesses, anterior chamber depth (ACD), anterior chamber volume (ACV), irido-corneal angle (ICA), corneal volume (CV) and Ocular Surface Disease Index (OSDI) results were analyzed. ResultsThe mean MG loss values were 29.9 ± 11.9 and 20.8 ± 11.0 in the PCOS and control groups, respectively (p < 0.001). MG loss (meiboscale ≥ 1) was determined in 64 (96.9%) eyes in the PCOS group and in 36 (85.7%) eyes in the control group. There was no significant difference between the groups in respect of NITBUT, OSDI, Km, CCT, TCT, ACD, ACV, ICA and CV values (p > 0.05, for all). ConclusionMG loss is a physiological process which is distinct in PCOS patients, but does not cause tear film alterations. Further studies are needed to show the contributing factors of MGD in PCOS patients.

Implications of Diagnostic Drops on Scheimpflug Tomography: The Proper Order for Clinical Testing.

The purpose of this article was to study the impact of instillation of 1% fluorescein and mydriatics on measurements made by Scheimpflug imaging. This was a cross-sectional study of patients who had measurements of corneal shape (maximum keratometry and best fit sphere of anterior and posterior corneal surfaces), pachymetry (at the pupil center, corneal apex, and thinnest location), and anterior chamber parameters (depth, volume, and angle of anterior chamber and corneal volume) using the Pentacam HR before and after the instillation of fluorescein and mydriatics. Group A had baseline measurements that were repeated 1.5 hours after the instillation of 1% fluorescein and 0.8% tropicamide+ 5% phenylephrine eye drops. Group B had baseline measurements that were repeated 10 minutes after the instillation of 1% fluorescein, and group C had baseline measurements that were repeated 1.5 hours after the instillation of mydriatics. Overall, 131 eyes of 131 patients were studied: 87 in group A, 28 in group B, and 16 in group C. Significant differences and wide variations were noted in corneal pachymetry and anterior chamber parameters in all 3 groups. The highest magnitude and range of difference was observed in pachymetry at the pupil center (17 ± 53.5 μm) and in anterior chamber volume (26.7 ± 69.8 mm 3 ). Corneal shape measurements of anterior and posterior corneal surfaces were not significantly affected by either fluorescein or mydriatics. Pupillary dilation also affected the ability of the Pentacam to accurately trace the pupil margin in 19.5% of cases. For consistent and accurate measurements, it is important that Scheimpflug imaging be performed before other tests which may need the instillation of fluorescein or mydriatics.

The relationship of ocular parameters with clinical parameters and disease-related quality of life in patients with systemic sclerosis: A cross-sectional study.

To evaluate choroidal thickness (CT), corneal parameters, and scleral thickness (ST) in patients with systemic sclerosis (SSc) and to determine their relationship with disease-related quality of life (QoL). The study included 38 patients with SSc and 40 healthy controls. A detailed ocular examination was performed on all participants. Corneal parameters such as K1, K2, Km, corneal volume (CV), central corneal thickness (CCT), and ST at a distance of 1000, 2000, and 3000μm from the scleral spur were measured. CT was measured at five points, including the subfoveal area and the temporal and nasal points at radii of 750.0 and 1500.0μm. The scleroderma health assessment questionnaire (SHAQ) was administered to SSc patients to investigate the disease-related QoL. Individuals with SSc had thicker ST at all distances from the scleral spur (P=0.008, P=0.001, P=0.002, respectively). All corneal parameters were significantly lower in the SSc group than in the control group (P<0.05). Moreover, SSc patients had significantly lower median CT at N750.0, N1500.0, T750.0, and T1500.0 points and thinner subfoveal CT than healthy controls (P<0.05). There was a weak-moderate negative correlation between ST and the components of the SHAQ scale and SHAQ-global. Despite not having ocular involvement, SSc patients had thicker ST but thinner CT and corneal parameters than healthy controls. This may indicate subclinical inflammation in patients with SSc. Only ST was affected by organ involvement and QoL among the ocular parameters.

Corneal Remodeling After Myopic SMILE Versus FS-LASIK: A Spatial Analysis of Short- and Mid-Term Corneal Thickness, Volume, and Shape Changes.

To evaluate the short- and mid-term changes of corneal thickness spatial profile (CTSP), corneal volume distribution (CVD), and corneal asphericity after small-incision lenticule extraction (SMILE) for correction of myopia and astigmatism and compare the results with femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Thirty eyes of 18 patients who underwent SMILE were compared with a group of 30 eyes of 16 patients who underwent FS-LASIK. The groups were matched for preoperative central corneal thickness and lenticule thickness/ablation depth. Scheimpflug corneal tomography was performed preoperatively and postoperatively at 2 months and 3 years. The CTSP was evaluated on 4 concentric rings (2, 4, 6, and 8 mm). The CVD was evaluated at 3 concentric zones (3, 5, and 7 mm). Changes in the anterior and posterior asphericity at a 6-mm zone were also evaluated. Between the 2-month and 3-year examination, the CTSP showed a similar increase for both groups at all measured points and rings ( P ≥ 0.168). The CVD also showed a similar increase for both groups at all measured zones ( P ≥ 0.278). The anterior corneal asphericity remained stable after SMILE (2-mo Q = 0.46 ± 0.27; 3-yr Q = 0.45 ± 0.27; P = 0.711) but decreased significantly after FS-LASIK (2-mo Q = 0.52 ± 0.47; 3-yr Q = 0.47 ± 0.44; P = 0.028). Similarly, the posterior corneal asphericity remained stable after SMILE (2-mo Q = -0.11 ± 0.15; 3-yr Q = -0.11 ± 0.13; P = 0.902) but decreased significantly after FS-LASIK (2-mo Q = -0.13 ± 0.14; 3-yr Q = -0.16 ± 0.15; P = 0.034). CTSP and CVD between the 2-month and 3-year examination showed a similar increase after SMILE and FS-LASIK. During the postoperative course, the anterior and posterior corneal asphericity remained more stable after SMILE compared with FS-LASIK.

Is keratoconus associated to thyroid diseases? Assessment of the corneal parameters in patients with congenital hypothyroidism.

To investigate the association between keratoconus and congenital hypothyroidism (CH). Patients were enrolled in this study and divided into two groups. The first group comprised 31 subjects (11M:20F) with the mean age of 15.2 ± 3.9 years. affected by CH, and the control group was composed by 19 healthy individuals (8M:11F) aged 14.3 ± 4.6 years. All patients underwent complete ophthalmologic examination with visual acuity assessment, refraction, slit lamp examination, and retinoscopy. Corneal parameters were measured using Scheimpflug camera (Pentacam® Oculus, Germany). The main outcome measures considered for evaluation were: average corneal curvature (K), central corneal thickness (CCT), anterior elevation and posterior elevation at the thinnest point, corneal volume (CV), anterior chamber depth (ACD), and anterior chamber volume (ACV). Additionally, data from Belin/Ambrosio Enhanced Ectasia Display (BAD) and the high order aberrations were evaluated. Kolmogorov-Smirnov test was used to verify the Gaussian distribution, the comparison between the controls and cases group was performed by Mann-Whitney nonparametric test. A p value less than 0.05 was considered to be statistically significant. The odds ratio was performed in order to quantify the relationship between the congenital hypothyroidism and abnormal values displayed on front BAD. The significant difference in the refractive status between both groups was observed. As to examined corneal and anterior chamber parameters no statistical differences were detected. Congenital hypothyroidism diagnosed and treated since the early postnatal life doesn't induce abnormalities of corneal parameters suggestive for keratoconus.

EVALUATION OF ANTERIOR SEGMENT PARAMETERS IN PATIENTS WITH KERATOCONUS WITH PENTACAM DEVICE

OBJECTIVE: It was aimed to evaluate the changes observed in the anterior segment parameters in patients with keratoconus using Pentacam device according to the severity of the disease and to compare the determined results with those obtained from the healthy individuals.MATERIAL AND METHODS: The data obtained by the Pentacam device for 104 eyes of 52 keratoconus patients and 120 eyes of 60 healthy individuals were retrospectively evaluated. Demographic features of the patients, the corneal curvature of the anterior and posterior surface, the asphericity and the elevation values (K1, K2, corneal astigmatism, and average asphericity), thinnest corneal thickness (TCT), apex corneal thickness (ACT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber angle (ACA), and anterior chamber volume (ACV) outcomes were recorded.RESULTS: The average age was 30.8±11.6 years in the Keratoconus group (22 Female, 30 Male) and 32.4±12.4 years in the control group (26 Female, 34 Male). The groups were compatible with each other in terms of age and gender (p=0.32, p=0.89, respectively). In the classification based on keratometry readings, keratoconus level was grouped as mild in 63 eyes, medium in 26 eyes, and severe in 15 eyes. In keratoconus patients, there was a significant difference in curvature, asphericity, and elevation values of the corneal anterior and posterior surfaces between the groups (p&amp;lt;0.001). TCT was the highest in the mild group and lowest in the severe group, and the difference between the groups was significant (p&amp;lt;0.05). ACD was 3.21±0.34 in the mild group, 3.27±0.26 in the medium group, and 3.79±0.53 in the severe group, and the difference was also significant (p&amp;lt;0.05).CONCLUSIONS: Significant changes in the values of curvature, asphericity, and elevation of both corneal anterior and posterior surfaces and the parameters of the anterior segment of the cornea are observed with the progression of keratoconus.

Changes in anterior segment parameters and presence of dry eye disease in patients with acromegaly: A Sirius topography study combined with meibography

PurposeTo investigate anterior segment parameters (ASPs) and dry eye disease (DED), including the status of the meibomian glands, in patients with acromegaly. MethodsIn this cross-sectional, comparative study, 36 acromegaly patients and 40 healthy sex- and age-matched controls were included. Participants received a comprehensive ophthalmological examination, including intraocular pressure measurements with Goldmann applanation tonometry (IOPGAT) and central corneal thickness corrected intraocular pressure (IOPCCT) measurements, and were evaluated for ASPs and DED. For ASPs, white-to-white (WTW), apical (ACT) and thinnest corneal thickness (TCT), corneal volume (CV), keratometry readings (K1, K2, and Kmean), anterior chamber depth (ACD) and volume (ACV), and iridocorneal angle (ICA) were obtained via Sirius topography. DED was assessed with Schirmer's test, tear breakup time (TBUT), and Ocular Surface Disease Index (OSDI) scores. Meibography scores (MSs) were obtained with the Sirius topography device. ResultsPatients had higher mean IOPGAT (P = .006), IOPCCT (P = .01), ACT (P = .024), and TCT (P = .005) but narrower ICA (P = .014) than controls. Although Schirmer's test did not differ between the groups (P = .442), patients had higher OSDI (P < .001), higher MS (P = .001), and shorter TBUT (P = .002). ConclusionPatients with acromegaly have greater IOP, greater corneal thickness, but narrower ICA than healthy individuals, as well as DED with increased MSs, which suggests meibomian gland dysfunction.

Repeatability and Reproducibility of Anterior Chamber Angle Measurement with Swept-Source Optical Coherence Tomography in Patients with Primary Angle Closure Suspect

ABSTRACT Purpose: To evaluate the inter- and intra-observer reliability of anterior chamber (AC) angle measurements obtained by swept-source optical coherence tomography (SS-OCT). Methods: Forty-eight consecutive patients diagnosed with primary angle closure suspect (PACS) were included. Three masked observers at different training levels (one glaucoma specialist, one ophthalmology resident, and one pre-medical college student) measured 192 SS-OCT images of the PACS patients. One observer (the glaucoma specialist) repeated measurements 1 week later. SS-OCT parameters included: Anterior segment volume, including corneal, AC, and iris volume; anterior segment dimensions, including AC depth and width (ACD, ACW), and lens vault (LV); and angle parameters, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and the trabecular iris angle (TIA). Intraclass correlation coefficients (ICCs) were used to measure reliability. Results: For inter-observer reproducibility, ICCs of corneal, AC, and iris volumes were 0.952 to 0.998. ICCs of ACD at all axes were above 0.989. ICCs of ACW and LV were smallest in the 90°-270° axis (0.751 and 0.768) but not significantly different from other axes. ARA, TISA, and TIA at all angles had significantly smallest ICCs 250 µm from the scleral spur compared with 500 µm and 750 µm. The ICCs comparing observers with different training levels had similar ranges and followed similar trends. For intra-observer repeatability, the smallest ICC was 0.843. Decreasing AC depth correlated with increased inter-observer reproducibility. Conclusions: We found excellent intra-observer repeatability for all SS-OCT parameters. Angle measurements have more variation among the observers when taken 250 µm from the scleral spur. Shallow AC might lead to more variability for angle parameters. Non-expert observers may be recruited for high-quality image grading with standard training.

Corneal Parameters in Patients with Multiple Sclerosis: A Pilot Study.

To evaluate the corneal topographic parameter values measured with the Pentacam Scheimpflug system in patients with multiple sclerosis (MS). A total of 108 eyes of 62 MS patients were studied. In addition to a complete examination of anterior and posterior segments, all patients were scanned using the Pentacam Scheimpflug camera. The diagnosis of MS was made according to the McDonald criteria. All MS patients were clinically assessed using the Multiple Sclerosis Severity Score (MSSS). The mean age was 38.89 ± 10.18 years (36.16 - 41.30) for MS patients and 40.94 ± 9.44 years (38.49 - 43.11) for the controls (p = 0.26). Only central corneal thickness (CCT) and corneal volume (CV) values were significantly lower in MS patients (p < 0.001). The other corneal parameters were not significantly different between the study eyes and control eyes (p > 0.05 for all). Pachymetric measurements at the corneal apex were 525.69 ± 29.35 (518.29 - 533.67) µm for the study eyes versus 563.13 ± 23.70 (562.13 - 576.36) µm for the control eyes. CV were 59.22 ± 4.11(58.18 - 60.20) mm3 for the study eyes versus 62.78 ± 3.09 (62.38 - 64.00) mm3 for the control eyes. This is the first study that has reported lower CCT and CV measurements in MS patients than healthy subjects of a similar age. These results should be supported by further studies.

Refractive outcome and tomographic changes after Descemet membrane endothelial keratoplasty in pseudophakic eyes with Fuchs\u2019 endothelial dystrophy

PurposeTo analyze refractive and topographic changes secondary to Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes with Fuchs’ endothelial dystrophy (FED).MethodsEighty-seven pseudophakic eyes of 74 patients who underwent subsequent DMEK surgery for corneal endothelial decompensation and associated visual impairment were included. Median post-operative follow-up time was 12 months (range: 3–26 months). Main outcome measures were pre- and post-operative manifest refraction, anterior and posterior corneal astigmatism, simulated keratometry (CASimK) and Q value obtained by Scheimpflug imaging. Secondary outcome measures included corrected distance visual acuity (CDVA), central corneal densitometry, central corneal thickness, corneal volume (CV), anterior chamber volume (ACV) and anterior chamber depth (ACD).ResultsAfter DMEK surgery, mean pre-operative spherical equivalent (± SD) changed from + 0.04 ± 1.73 D to + 0.37 ± 1.30 D post-operatively (p = 0.06). CDVA, proportion of emmetropic eyes, ACV and ACD increased significantly during follow-up. There was also a significant decrease in posterior corneal astigmatism, central corneal densitometry, central corneal thickness and corneal volume over time (p = 0.001). Only anterior corneal astigmatism and simulated keratometry (CASimK) remained fairly stable after DMEK.ConclusionDespite tendencies toward a hyperopic shift, changes in SE were not significant and refraction remained overall stable in pseudophakic patients undergoing DMEK for FED. Analysis of corneal parameters by Scheimpflug imaging mainly revealed changes in posterior corneal astigmatism pointing out the relevance of posterior corneal profile changes during edema resolution after DMEK.

Comparison of the corneal volume and the anterior chamber volume using Pentacam in individuals with healthy, subclinical and early keratoconus eyes

AIM: To compare the anterior chamber volume and corneal volume using Pentacam in people with early keratoconus, subclinical keratoconus, and healthy subjects. METHODS: This epidemiologic study was performed on 63 patients who were candidates for refractive surgery. We classified our patients into three groups as normal, subclinical keratoconus, and early keratoconus according to the Amsler-Krumeich criteria. We collected demographic information, including age and sex, and obtained a full medical history of the patients. Complete visual examination was performed for all patients. Then, using Pentacam, corneal volume and anterior chamber volume were measured among three groups. RESULTS: Corneal volume in the control group was significantly higher than the subclinical keratoconus and early keratoconus groups (P&lt;0.05), but the anterior chamber volume was not significantly different between the groups (P&gt;0.05). CONCLUSION: Measuring the corneal volume can help to distinguish the eyes with subclinical keratoconus and early keratoconus from normal eyes. The chamber volume might not differ remarkably among people with subclinical keratoconus, early keratoconus, and those with normal eyes.

N-acetylcysteine alleviates ocular surface damage in STZ-induced diabetic mice by inhibiting the ROS/NLRP3/Caspase-1/IL-1β signaling pathway

Diabetes mellitus (DM) induces damage to the ocular surface, which leads to vision decline. In the current study, we investigated whether N-acetylcysteine (NAC) plays a protective role in diabetes-induced ocular surface damage. The diabetic mice model was treated with 0.3% NAC topically. Corneal epithelial integrity, tear volume and corneal sensitivity were examined by sodium fluorescein staining, phenol red cotton thread and esthesiometer respectively. The level of reactive oxygen species (ROS) was measured with 2’,7-dichlorofluorescein diacetate. The expression of NLRP3, IL-1β and caspase-1 were evaluated by RT-PCR, western blot and immunostaining. The level of SOD1 was assessed by RT-PCR. We found that the expression of NLRP3, IL-1β and caspase-1 were elevated in diabetic cornea and conjunctiva. Treatment with NAC improved corneal epithelial integrity, increased tear production and corneal sensitivity in diabetic mice. Moreover, NAC markedly attenuated ROS accumulation and decreased NLRP3, IL-1β and caspase-1 levels in diabetic cornea and conjunctiva. These results suggest that NAC improves ocular surface damage in STZ-induced diabetic mice, which may be related to the inhibition of the ROS/NLRP3/Caspase-1/IL-1β signaling pathway.

Análise comparativa entre os índices tomográficos em pacientes com ceratocone inicial

Objective: To assess sensitivity of corneal volume, corneal asphericity, and D index in early diagnosis of keratoconus. Methods: A cross-sectional analytical study, carried out between December 2018 and October 2020, which analyzed the medical records of 39 patients (78 eyes) diagnosed as keratoconus by a single corneal specialist, using the criteria of Belin-Ambrosio Enhanced Ectasia Display. The collected data were anterior asphericity, posterior asphericity, D index and its parameters (Da, Db, Dt, Dp and Df). The data were entered [...]

Correlation of Ocular Biometric Parameters and Macular Ganglion Cell Layer in Normal Eyes

ABSTRACT Purpose To determine the association between ocular biometric parameters and macular ganglion cell layer (MGCL) thickness in normal eyes. Methods This observational cohort study was conducted with 76 eyes of 76 healthy subjects. Keratometry, pachymetry, corneal volume, iridocorneal angle were measured with Sirius (CSO, Florence, Italy); axial length, anterior chamber depth, anterior chamber volume, corneal diameter were measured with IOL Master (Carl Zeiss Meditec, Dublin, California). For all participants, serial horizontal Spectralis Domain Optical Coherence Tomography (SD-OCT, Heidelberg Engineering, GmbH, Dossenheim, Germany) scans of the macula and peripapillary retinal nerve fiber layer (RNFL) analysis were obtained using SD-OCT. The relationship between numerical variables was given by Pearson correlation coefficient. Results The mean age of the subjects was 36.3 ± 11.9 years (between 19 and 70 y). Fifty-one patients were female (67.1%) and twenty-five patients were male (32.9%). MGCL was found to be correlated with anterior chamber depth, anterior chamber volume, iridocorneal angle, axial length and white to white (p = .015 r = 0.594, p = .002 r = 0.365, p = .013 r = 0.299, p = .004 r = 0.335, p = .013 r = 0.289, respectively). In addition, MGCL was correlated positively with the mean global and superotemporal RNFL (p ≤ 0.005). However, neither central corneal thickness nor keratometry values were found to be correlated with MGCL. Conclusion The results of this study showed that MGCL thickness is affected by ocular biometric parameters. Therefore, these parameters should be taken into consideration when interpreting MGCL thickness measurements in the diagnosis of glaucoma.

Anterior Chamber Characteristics, Endothelial Parameters, and Corneal Densitometry After Descemet Stripping Automated Endothelial Keratoplasty in Patients With Fuchs Dystrophy.

PurposeTo compare anterior segment parameters in patients with Fuchs endothelial dystrophy (FED) who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) in one eye and no corneal surgery in the fellow eye.MethodsThis prospective study was conducted on 28 eyes of 14 patients with FED who underwent DSAEK in one eye at least one year prior (DSAEK group) and no corneal surgery in the fellow eye (control group). Each eye was analyzed with the anterior segment optical coherence tomography, specular microscopy, and Scheimpflug imaging systems. Data were compared between the two groups.ResultsThe mean age of the patients was 76.9 7.0 years. There were no statistically significant differences in the mean central corneal thickness (CCT), central anterior chamber depth, anterior chamber angle parameters, cylinder and keratometry values between two groups (all P-values 0.05). The paracentral corneal thickness, corneal volume, endothelial cell density, and hexagonal cell ratio measurements were statistically significantly higher in the DSAEK group than the control (all P-values < 0.05), and anterior chamber volume in the DSAEK group was significantly less than the control (P = 0.046). While posterior and total corneal densitometry values in the DSAEK group were statistically significantly lower than the control (P < 0.001 and P = 0.011, respectively), there were no statistically significant differences in the anterior or middle corneal densities (P = 0.108 and P = 0.134, respectively).ConclusionWe found that total corneal densitometry value decreased in DSAEK group. Although DSAEK surgery did not affect the anterior chamber angle parameters, it reduced the anterior chamber volume and increased the corneal volume and paracentral corneal thickness due to the addition of the DSAEK graft.