Central Corneal Thickness Values Research Articles

Effect of Obstructive Sleep Apnea on Corneal Morphological Characteristics.

To determine central corneal thickness (CCT) and the corneal parameters in patients with obstructive sleep apnea (OSA), evaluate the relationship between the severity of OSA, minimum peripheral capillary oxygen saturation (min. SpO2), and corneal morphological characteristics. Patients with OSA diagnosed by full-night polysomnography before treatment were included. Patients with OSA were divided into 3 groups according to the Apnea-Hypopnea Index (AHI). The control group (CG) was examined to exclude the possibility of OSA and ocular diseases. The following data were recorded: age, sex, body mass index, ophthalmologic evaluation, and the results of polysomnography. A total of 114 eyes were studied: 74 eyes of patients with OSA and 40 eyes of the CG. The mean age was 57 ± 6 years. The mean values of CCT and endothelial cell density (ECD) varied significantly between the patients and the CG (P < 0.001). The mean values of CCT, ECD, cell variation coefficient (CV), and hexagonal cell percentage (HEX) in the group of patients with OSA were 535.28 ± 21.32 μm, 2632 ± 333, cells/mm. 31.8 ± 3.9, and 55.6 ± 6.9%, respectively. The mean CCT and ECD values for each group were lower than those for the CG. A significant negative correlation was found between CCT and ECD for AHI values (r = -0.390, P = 0.011 and r = -0.109, P = 0.040, respectively), and a weak positive correlation between CCT and ECD was found for min. SpO2 (r = 0.282, P = 0.020 and r = 0.332, P = 0.018, respectively). CV and HEX did not significantly differ between the groups and did not correlate with the results of polysomnography. Hypoxia is associated with significant changes in CCT and ECD. In patients with OSA, these parameters varied significantly when compared with the subjects in the CG. The severity of hypoxemia and the increase in AHI values reduce CCT and ECD in patients.

CENTRAL CORNEAL THICKNESS MEASURED BY THE OCULYZER, BIOGRAPH, AND ULTRASOUND PACHYMETRY

Central corneal thickness (CCT) is an important parameter in selecting patients before any corneal refractive procedures and in postoperative follow-up, in monitoring the patients with corneal disorders such as keratoconus and Fuchs' dystrophy, as well as in adjusting the intraocular pressure according to central corneal thickness. The aim of the paper was to compare the results of CCT measurements obtained by different measurement instruments: Oculyzer, BioGraph and ultrasound pachymetry. CCT was measured in 64 eyes of 32 patients. The measurements were performed in a specialized Eye Hospital Maja Clinic in Nis, using the following instruments: WaveLight Allegro Oculyzer, WaveLight Allergo Biograph, ultrasound pachymeter DGH Pachette 3. The mean values of central corneal thickness obtained from different devices were compared. The mean values of CCT (± standard deviation) obtained with Oculyzer were 552.94 µm ± 22.88 µm, 556.56 ± 25.32 µm obtained with BioGraph, and 559.46 ± 26.0 µm measured by ultrasound pachymeter. There were no statistically significant differences among different measurement devices. The CCT measurements with the Oculyzer, BioGraph, and ultrasound pachymetry do not show statistically significant differences, so the results of CCT measurements obtained by using any of these devices may be considered valid.

Short term effects of intravitreal anti-vascular endothelial growth factor agents on cornea, anterior chamber, and intraocular pressure

Objective: To evaluate short term changes in anterior chamber depth (ACD), central corneal thickness (CCT), intraocular pressure (IOP), and corneal endothelial cell density (ECD) after intravitreal anti-vascular endothelial growth factor (VEGF) injections.Materials and methods: A total of 100 eyes from 100 patients, who were naive for intravitreal injection treatment, were included in this retrospective study. Patients who received only a single type of intravitreal anti-VEGF injections (bevacizumab, ranibizumab, or aflibercept) for two consecutive months were examined. ACD, CCT, IOP, and ECD measurements were taken at pre-injection and one month after the first and second injections and were compared.Results: The mean corneal ECD for all eyes and phakic eyes was significantly lower one month after the first (p = 0.041 and p = 0.047, respectively) and second injections (p = 0.013 and p = 0.034, respectively) compared to the values at pre-injection levels. Similarly, the mean ACD of all eyes and phakic eyes was significantly lower one month after the first (p < 0.001 and p < 0.001, respectively) and second injections (p < 0.001 and p < 0.001, respectively) compared to the values at pre-injection levels. However, there was no significant difference in pseudophakic eyes one month after the first and second injections (ECD, p = 0.28 and p = 0.23; ACD, p = 0.75 and p = 0.71, respectively). There was no significant change in IOP and CCT values at pre-injection and one month after the first and second injections for all eyes and for both the phakic and pseudophakic eyes.Discussion: After the anti-VEGF injections, IOP and CCT values were not significantly changed and were similar in all eyes and phakic eyes; however, in these groups, there was a small but statistically significant decrease in ACD and ECD. On the contrary, there was no significant difference in pseudophakic eyes. Clinicians performing intravitreal injections must be aware of these associations for a better understanding of ACD and ECD changes in phakic eyes.

Comparison of changes in corneal endothelial cell density and central corneal thickness between conventional and femtosecond laser-assisted cataract surgery: a randomised, controlled clinical trial

Background/AimTo identify changes in endothelial cell density (ECD) and central corneal thickness (CCT) in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification surgery (CPS).MethodsThis is an intraindividual...

Significance of dynamic contour tonometry in evaluation of progression of glaucoma in patients with a history of laser refractive surgery

AimsIn this study, we tested the hypothesis that intraocular pressure (IOP) parameters measured by dynamic contour tonometry (DCT) would be more relevant in progression of glaucoma when there is a...

Central Corneal Thickness in Childhood Cataract.

We explored elevated central corneal thickness (CCT) in children with cataracts as possibly reflecting preexisting corneal malformation related to specific cataract morphology. All children consecutively seen during the study periods who had cataracts and corneal pachymetry as part of their routine care were enrolled at academic centers in large cities of Canada and the United States. Study data collected included age, sex, CCT, and cataract morphology. Differences among cataract morphology groups with respect to mean CCT measurements were evaluated and compared with a historical control thickness of 558 μm. A total of 96 children were enrolled in this study. The average subject age was 5.1 years, and 55 children (57%) were female. The mean CCT value for all subjects was 566.1 μm. There was little evidence to conclude that the cataract morphology groups differed from each other (P = 0.65) or from controls with respect to CCT. In children, CCT is likely independent of cataract morphology. This implies that factors other than preoperative malformation are more likely related to elevated CCT observed in children with aphakia and pseudophakia.

Two-year outcomes of a randomized controlled trial of transepithelial corneal crosslinking with iontophoresis for keratoconus

To evaluate the 2-year clinical outcomes of corneal crosslinking (CXL) using transepithelial iontophoresis CXL (T-ionto CXL) in comparison with standard CXL for the treatment of progressive keratoconus. Single-site study. Randomized controlled clinical trial with identifier code NCT02117999. The eyes of the participants were randomized to have either T-ionto CXL and/or standard CXL. Assessments of uncorrected (UDVA) and corrected (CDVA) distance visual acuities (logarithm of the minimum angle of resolution [logMAR]), manifest refraction spherical equivalent, maximum simulated keratometry (K) (diopters [D]), corneal higher-order aberrations (HOAs), central corneal thickness (CCT), and endothelial cell density (ECD) were performed at 3days, 7days, and 1, 3, 6, 12, and 24months postoperatively. The study comprised 34 eyes (25 patients). There were 22 eyes in the T-ionto CXL group and 12 eyes in the standard CXL group. Two years after T-ionto CXL and standard CXL, the mean maximum K flattened by -1.05±1.20 D (P=.07) (20 eyes) and -1.51±.89 D (P<.001) (11 eyes), respectively. Two study cases (10%) and no control showed maximum K steepening of more than 1.0 D at 24months postoperatively. The mean change in CDVA was -0.08±0.15 logMAR (P=.04) and -0.02±0.06 logMAR (P=.34) after T-ionto CXL and standard CXL, respectively. A significant average decrease in the myopic defocus (+0.81 D; P<.05) was found in both groups. No significant differences in the outcome measures between treatments were found at 24months. The corneal HOAs, CCT, and ECD values did not change significantly in any group at 2years postoperatively. Clinically significant topographic, visual, and refractive improvements were found 2years after T-ionto CXL; standard CXL showed more significant corneal apex flattening than the transepithelial iontophoresis protocol.

Central corneal thickness and intraocular pressure in type II diabetes

Background: Diabetes is a rapidly-growing global health problem with a significant impact on morbidity and mortality due to diabetes-related complications. Objective: The purpose of this study was to assess the impact of type II diabetes on the central corneal thickness (CCT) and intraocular pressure (IOP). Patients and Methods: This prospective case-control study was performed at the ophthalmic department of Al-Zahraa University Hospital. It was conducted on 30 participants with type II diabetes and 10 healthy control (both eyes were included). Diabetics were categorized into 3 groups, diabetics without retinopathy, with non-proliferative diabetic retinopathy (NPDR) and with proliferative diabetic retinopathy (PDR).Each group contained 10 participants. Complete ophthalmic examination was done for all participants including, visual acuity, slitlamp, fundus examination, measurement of IOP and CCT. Fundus photography and measurement of glycosylated hemoglobin A1c (HbA1c) were done for diabetics. Results: Diabetics with PDR exhibited significantly higher IOP and CCT values compared to other groups. The IOP was significantly correlated with CCT and with the duration of diabetes. Conclusion: Diabetics with PDR had a significantly elevated IOP and thicker corneas than normal subjects. These data emphasize the importance of considering CCT measurements in diabetics for proper interpretation of IOP.

Anterior segment parameters measured in young healthy cats using a rotating Scheimpflug camera.

The purpose of this study is to measure parameters of the anterior segment of normal feline eyes using a rotating Scheimpflug camera in young and adult cats. Sixteen domestic short-haired (DSH) healthy cats (seven castrated males and nine spayed females) with a mean age of 17months (SD=3.5) were anesthetized. Cats were considered immature and adults if they were < or ≥12months of age, respectively. The keratometric values, the anterior chamber depth (ACD), and central corneal thickness (CCT) of the right eye of each animal were measured using a Pentacam Oculus topographer. The repeatability of the measures was assessed by calculating the coefficient of variation of the successive measures in cats (five repetitions per cat). We performed an ANOVA to test the effect of age on the parameters measures. The mean CCT and ACD were 601.97±38μm and 5.27±0.04mm, respectively. No significant differences were observed between adult and young cat's measures. The average keratometric value was 39.6±0.3D. The mean average cylindrical error was 2.48±0.35D (43.75% "against-the-rule" astigmatism and 43.75% "oblique" astigmatism). The Oculus Pentacam under clinical conditions give CCT and ACD values very similar to those reported in previous studies. Corneal astigmatism measures were markedly elevated (>2D). Further studies with a larger population of cats of various breeds and ages are needed to confirm or refute these results, using a rotating Scheimpflug camera.

Functional outcome of repeat Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following graft failure after primary DMEK.

PurposeTo evaluate if repeat Descemet membrane endothelial keratoplasty (DMEK) is appropriate to achieve functional improvements in patients with corneal decompensation from secondary graft failure after primary DMEK.MethodsThis is a retrospective monocentric cohort study including 13 eyes of 13 patients with repeat DMEK for corneal decompensation following primary DMEK. Eyes with primary DMEK only and comparable preoperative corrected distance visual acuity (CDVA) served as control. Main outcome parameter was CDVA. Secondary outcome measures were central corneal thickness (CCT), endothelial cell density, and rebubbling rate (RR).ResultsThe average time interval (±SD) between primary and secondary DMEK was 12.5±6 months. Preoperative CDVA (logMAR) was 1.97±0.90 in the repeat DMEK group and 1.38±0.92 in the primary DMEK group. At 6 months, both groups showed significant improvement in visual acuity (repeat DMEK group, 0.49±0.35, P<0.01 and primary DMEK group, 0.40±0.36, P<0.01). CDVA did not differ significantly between both groups at all time points examined (1, 3, and 6 months postoperatively). Mean CCT values at 3 and 6 months postoperatively did not differ significantly between the two groups (P>0.05). The RR was 23% (n=3) in both groups.ConclusionRepeat DMEK is a useful therapeutic approach in the setting of corneal decompensation following primary DMEK. Functional results of repeat DMEK, visual acuity in particular, are comparable to patients with single DMEK only.

ROLE OF VITAMIN D IN ENDOTHELIAL CELL OF RETINA

Vitamin D deficiency is a common health problem worldwide. Many parts of the human eye, including the epithelium of the cornea, lens, ciliary body, and retinal pigment epithelium, as well as the corneal endothelium, ganglion cell layer, and retinal photoreceptors, contain vitamin D receptor. Physiological effects of vitamin D From an ocular point of view, the role in macular and retinal health had been advanced, as well as the involvement in corneal inflammatory response, wound healing, and dry eye disease. The most important effect of vitamin D is on, phosphorus, calcium metabolism and on bone mineralization. Recently, it was observed that vitamin D deficiency and insufficiency are related with common cancers, cardiovascular diseases, metabolic syndromes, infectious, and many chronic diseases including autoimmune disease. Benefits of vitamin D may be amplified through synergistic interaction with topical corticosteroids which accelerates improvement in corneal shape and optics, substantially benefiting the control of ocular surface disease and dry eye symptoms. Aqueous humour is the primary source responsible for the feeding of corneal endothelial layer hence endothelial abnormalities can be expected due to accumulated inflammatory cytokines and multiple toxic products in the aqueous humour of the patients with vitamin D deficiency.&#x0D; MATERIAL AND METHODS: Subjects were selected with vitamin D deficiency in the age group of 20–55 years. 50 patients having serum vitamin D levels &lt;15 ng/ml were included in the study. Serum vitamin D levels of &lt;15 ng/ml were included in the control group. Vitamin D levels in tear fluid were measured by direct competitive chemiluminescent enzyme linked immunoassay. A complete ophthalmic evaluation was performed in all participants which includes assessment of visual acuity, anterior segment evaluation and posterior segment evaluation. Specular microscopy was performed on the eyes of the patients with vitamin D deficiency and healthy control group individuals. Corneal endothelial cell density (CD) and central corneal thickness (CCT) values were calculated automatically using the software of the specular microscope. &#x0D; RESULTS: The study group included 23 male and 27 female subjects while study group included 24 male and 26 female. Mean age of male in study group was 46.4 ± 12.56 and female was 45.6 ± 11.77. In control group mean male age was 48.5 ± 9.25 and female age was 49.56 ± 12.55. In study group Mean Corneal endothelial cell density (CD) was observed as 2632.89 ± 189.25 cells/mm 2 and Mean central corneal thickness (CCT) was 587.2 ± 25.89 μ. In control group Mean Corneal endothelial cell density (CD) was observed as 2954.97 ± 116.89 cells/mm 2 and Mean central corneal thickness (CCT) was 546.0 ± 36.22 μ. Vitamin D levels of Tears in study group was 8.4 ± 1.7 ng/ml and in control group it was 16.2 ± 2.3 ng/ml.&#x0D; CONCLUSION: It has been observed that there is statistically significant difference in the corneal endothelial cell density (CD) and central corneal thickness (CCT) in patients with vitamin D deficiency. It was observed that Vitamin D is present in tear fluid and there is significant difference in the levels of vitamin D in study and control group.

An investigation of the ocular toxic effects of levetiracetam therapy in children with epilepsy.

To investigate the potential toxic effects of levetiracetam monotherapy on ocular tissues in cases of pediatric epilepsy using optical coherence tomography (OCT). Thirty epileptic children (group 1) receiving levetiracetam monotherapy at a dosage of 20-40mg/kg/day for at least 1year with a first diagnosis of epilepsy and 30 age- and gender-matched healthy children (group 2) were included in the study. In addition to a detailed eye examination, peripapillary retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, foveal thickness (FT), and central corneal thickness (CCT) were measured in all children by means of spectral domain OCT. The data obtained from the two groups were then subjected to statistical analysis. The mean age of both groups was 12 ± 3.64years [1-12]. The mean duration of levetiracetam in group 1 was 24.07 ± 12.82months. Mean RNFL values in groups 1 and 2 were 106.1 ± 10.42 and 104.98 ± 10.04μm, mean GCC values were 94.72 ± 6.26 and 94.4 ± 6μm, mean FT values were 240.73 ± 17.94 and 240.77 ± 15.97μm, and mean CCT values were 555.1 ± 44.88 and 540.97 ± 32.65μm, respectively. No significant difference was determined between the two groups in terms of any parameter. Best corrected visual acuity values of the subjects in both groups were 10/10, and no color vision or visual field deficit was determined. Levetiracetam monotherapy causes no significant function or morphological change in ocular tissues in pediatric epilepsies.

Management of Corneal Ectasia after LASIK with Phototherapeutic Keratectomy Combined with Photorefractive Keratectomy and Collagen Cross-Linking.

Background To evaluate the efficacy of phototherapeutic keratectomy (PTK) combined with photorefractive keratectomy (PRK) and riboflavin with ultraviolet-A collagen cross-linking (CXL), performed sequentially on the same day, in the management of corneal ectasia after LASIK. Methods This retrospective review comprised consecutive patients with corneal ectasia after LASIK. The patients were administered PTK and PRK on the previous corneal flap, and CXL was given on the same day by the same surgeon. The main outcome measures included age, sex, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent refraction, cylinder equivalent refraction, steep and flat keratometries (K), central corneal thickness (CCT), endothelial cell count, corneal haze, and ectasia stability. Mean follow-up period was 6, 12, and 24 months. Results Sixteen eyes of twelve patients were included in the study. Twenty-four months after administration of PTK combined with PRK and CXL, a significant improvement in UDVA was observed. Mean cylinder equivalent refraction was significantly reduced at 6, 12, and 24 months postoperatively. However, no significant reduction was observed in spherical equivalent refraction. A significant reduction in the flat K and steep K values was observed. No significant change in mean CCT value was observed. Mean endothelial cell count and morphology were unchanged between preoperative and postoperative patients. In addition, no obvious corneal haze was observed. Conclusions PTK combined with PRK and CXL on the same day is a safe and effective treatment in improving visual acuity in selected patients with corneal ectasia after LASIK.

Comparison of intraocular pressure and central corneal thickness in non-glaucomatous North- East Indian tribals versus general Indians

Purpose: To compare the intraocular pressure (IOP) and central corneal thickness (CCT) of non-glaucomatous North-East (NE) Indian tribals and general Indians. &#x0D; Materials and methods: In a prospective, cross-sectional study, the IOP and CCT of non-glaucomatous NE Indian tribals (n = 50) and non-glaucomatous general Indians (n = 50) were compared. Glaucoma was ruled out by history, detailed ocular examinations, and investigations.&#x0D; Results: There was very good correlation between the CCT and IOP values of right and left eyes (p = 0.940 and 0.847, respectively). The difference in the IOP values in the two groups was not statistically significant (p = 0.312 for Oculus Dexter [OD], p = 0.400 for Oculus Sinister [OS]). Similarly, the difference in the CCT values in the two groups was not statistically significant (p = 0.736 for OD and 0.613 for OS). The mean CCT and IOP OD for the whole population was 530.50 ± 35.42 μm and 13.80 ± 2.760 mmHg, respectively. By linear regression analysis, the IOP OD of the whole population had good correlation with CCT OD of the whole population (adjusted r2 = 0.084, p = 0.002), but not with age (adjusted r2=0.000, p=0.314) and sex (adjusted r2 = 0.010, p = 0.163). Similarly, CCT OD for the whole population did not have good correlation with age (adjusted r2 = -0.009, p = 0.762) and sex (adjusted r2 = -0.007, p = 0.603).&#x0D; Conclusions: In this study of individuals with normal corneas and without glaucoma, no racial variation was found in the CCT and IOP values of the two groups. The IOP OD of whole population had good correlation with CCT, but not with age and sex. There was good correlation between OD and OS values of IOP and CCT.

Comparison of rebound tonometry and non-contact airpuff tonometry to Goldmann applanation tonometry.

Purpose:The aim of this study was to compare the intraocular pressure measurements obtained from healthy subjects with the rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry in different age groups.Methods:A total of 180 eyes of 90 healthy subjects were included in the study. According to the subjects’ ages, the eyes were categorized into three groups: group 1 (age: 7–17 years), group 2 (age: 18–40 years), and group 3 (age: 41–75 years). Intraocular pressure was measured on each subject always in the same order: rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry. Central corneal thickness values were obtained using ultrasonic pachymetry. One-way repeated-measures analysis of variance, Pearson’s correlation coefficient, and Bland–Altman analysis were used for the statistical assessment.Results:The mean corneal thickness was found to be 604 ± 13 µm, 546 ± 15 µm, and 547 ± 15 µm in group 1, group 2, and group 3, respectively. Non-contact airpuff tonometry was significantly higher than both Goldmann applanation tonometry and rebound tonometry measurements in all groups (p < 0.001, for all). No statistical difference between Goldmann applanation tonometry and rebound tonometry measurements was found in group 1 (p = 0.248), group 2 (p = 0.63), and group 3 (p = 0.126). There was a significant positive correlation in the meaning of intraocular pressure measurements between rebound tonometry and non-contact airpuff tonometry; non-contact airpuff tonometry and Goldmann applanation tonometry; and Goldmann applanation tonometry and rebound tonometry in all groups.Conclusion:As a result, without need for topical anesthesia, fast measurement and ease-of-use rebound tonometry is a reliable alternative to Goldmann applanation tonometry in different age groups.

Central corneal thickness measurement using ultrasonic pachymeter, optical coherence tomography, and TMS-5 topographer

AIM:This study aimed to compare the central corneal thickness (CCT) measurements using Optical Coherence Tomography (OCT) and TMS-5 topographer with that taken with the gold standard digital Ultrasonic pachymeter (USP).MATERIALS AND METHODS:A total of 61 subjects (122 eyes) were prospectively and consecutively studied in a period from June 2016 to June 2017 at Sudan Eye Centre (SEC), Khartoum, Sudan. Besides the visual and refractive data, measurements of CCT were taken using OCT, TMS-5 and USP. Data analyzed using SPSS software for windows (IBM SPSS 20, IBM Corp., Armonk, NY).RESULTS:A statistically significant differences in mean CCT was detected between the three instruments (P < 0.001). USP was found to measure the CCT 29μm thicker than OCT and 22μm thicker than TMS-5 topographer. A significant difference was also found between OCT and TMS-5. OCT found to give the lower values of CCT compared to both USP and TMS-5 topographer. Further analysis showed that the three procedures were significantly and strongly correlated to each other (USP vs OCT, r = 0.77), (USP vs TMS-5, r = 0.78) and (OCT vs TMS-5, r = 0.80).CONCLUSION:Mean central corneal thicknesses (CCT) were comparable among OCT, TMS-5 topographer and the gold standard USP. However, there is a reproducible systematic difference between CCT measurements taken with the three devices. It is important to note in clinical practice, that measurements acquired by these three modalities are not directly interchangeable.

Effect of Acute Increases in Intraocular Pressure on Corneal Pachymetry in Rabbit Eyes Treated with Timolol Maleate

Objective: To evaluate in an in vivo rabbit model, the effect of topical timolol maleate therapy on the central corneal thickness response to acute intraocular pressure increases. Method: In this prospective and interventional controlled study, the central corneal thickness and intraocular pressure were measured in vivo in 12 rabbit eyes treated with topical timolol maleate for 1 month and in 12 controls at baseline, and after the intraocular pressure (measured by direct cannulation of the anterior chamber) was increased to 15 and 30 mmHg using a forced saline infusion into the anterior chamber. Results: There were no significant differences in the basal central corneal thickness values (control group, 373.2±12.9 µm; study group, 377.5±19.2 µm, p=0.5) or the central corneal thickness values when the intraocular pressure was increased to 15 mmHg (control group, 335.2±14.3 µm; study group, 330.0±32.1 µm, p=0.6) and to 30 mmHg (study group, 318.8±25.3 µm; control group, 329.8±21.0 µm, p=0.3). Conclusion: Rabbit corneas treated with topical timolol maleate for 1 month did not show a strain response to acute intraocular pressure increases that differed from control eyes. This is in contrast to a previous finding in which rabbit eyes treated with prostaglandin analogues had a greater decrease in central corneal thickness in response to a sudden intraocular pressure increase compared with untreated corneas.

Pregnancy and the eye. Changes in morphology of the cornea and the anterior chamber of the eye in pregnant woman.

The main goal of the study was to determine whether uncomplicated pregnancy and natural labor exert influence on the cornea and the anterior chamber of the eye. The study included 114 eyes of 57 women in age of 21-35 years old. Only patients in the physiological pregnancy and giving natural birth were recruited into study. Prospective observative examination was performed. Patients were diagnosed twice: in 36 HBD and 6 weeks after labor. Using the Scheimpflug camera (Pentacam system) the following parameters were assessed: central corneal thickness (CCT), keratometric parameters: flat (K1) and steep (K2), astigmatism value and axis, anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA). The statistical analysis was carried out in the StatSoft Statistica 13 program. CCT value is greater in the third trimester than in 6th week after the labour. ACD and ACA values are higher in 36 HBD than in the post-partum period but the difference is not statistically important (p > 0.05). K1, K2, cylindrical refraction error, axis of cylindrical refraction error do not change. Authors claim that it is the result from an increase in water retention in the corneal stroma as a response to hormonal changes. The plasticity of the anterior chamber seen before delivery can be a natural adaptive mechanism of the female body, which counteracts the excessive increase in intraocular pressure in the second stage of delivery.

Correlation between age and corneal edema in pediatric patients with Peters anomaly.

To evaluate corneal edema in different-aged pediatric patients with Peters anomaly and to correlate in vivo with ex vivo histopathologic findings. A retrospective cross-sectional study was performed. The medical records of patients diagnosed with Peters anomaly who underwent examination under anesthesia (EUA) between 2011 and 2015 were reviewed. Eyes in which central corneal thickness (CCT) measurements were taken were included. The thickest point in the CCT pachymetric map was used to objectively quantify corneal edema. Correlation between CCT and age was calculated. Additionally, a retrospective review of histopathologic studies of excised corneal buttons from pediatric eyes with Peters anomaly between 2011 and 2015 was performed. Eighteen eyes of 12 children were included. Mean age was 14 ± 15months, and mean CCT was 842 ± 304µm. A significant inverse correlation was noted between the CCT and the age of the patients, with lower CCT values in older children (r = 0.6; P = 0.01). Seven excised corneal buttons that underwent penetrating keratoplasty were reviewed. All corneal buttons showed absence of Descemet membrane and localized absence of endothelium. However, three specimens showed presence of corneal endothelium in areas of absent or attenuated Descemet membrane. In Peters anomaly, the CCT decreases with age, possibly due to a decrease in corneal edema. Histopathologic studies show cases of endothelial expansion in areas of absent or attenuated Descemet membrane. This may contribute to improved endothelial function and decreased edema with age.

Two-year topographic and densitometric outcomes of accelerated (45\u2009mW/cm2) transepithelial corneal cross-linking for keratoconus: a case-control study

BackgroundConventional corneal cross-linking is effective for retarding the progression of keratoconus. However the long-term efficacy and safety of accelerated (45 mW/cm2) transepithelial corneal cross-linking (ATE-CXL) on progressive keratoconus (KC) treatment is not fully understood. The purpose of this study is to evaluate the 2-year changes in corneal topographic parameters and densitometry values after ATE-CXL for KC.MethodsTwenty-five progressive eyes of 25 KC patients (KC group) and 25 eyes of 25 myopes without KC (control group) were enrolled. Corneal topography and densitometry values were evaluated pre-operatively and at 6, 12 and 24 months post-operatively in the KC group.ResultsThe mean values of flat keratometry (K1), steep keratometry (K2), mean keratometry (Km), corneal astigmatism (CA), maximum keratometry (Kmax), central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior corneal elevation (ACE) and posterior corneal elevation (PCE) all remained unchanged over time (all P values > 0.05). The densitometry values of the anterior, central, posterior and total layers over the annular diameters 0 mm to 2 mm (Φ0-2 mm) and Φ2–6 mm all decreased significantly (all P values < 0.05). At post-operative month 24, except for the densitometry value of the posterior layer (Φ0-2 mm), which was significantly lower than that of the control group (post hoc P = 0.010), all densitometry values obtained from the remaining locations of the KC eyes were equal to those of the control group (All post hoc P values > 0.05). Subgroups with Km ≥ 50.30D or ACE ≥35.3 μm progressed significantly when compared with those with Km < 50.30D (F = 8.167, P = 0.004) or ACE< 35.3 μm (F = 5.207, P = 0.022).ConclusionsK1, K2, Km, CA, Kmax, CCT, TCT, ACE, and PCE values may remain stable but severer KC patients tend to have poorer long-term outcomes. The densitometry values of the full corneal thickness (total layer over Φ0-2 mm and Φ2–6 mm) may decrease to normal levels at 2 years after ATE-CXL for KC.