Objective Evaluation of Corneal and Lens Clarity in Children With Type 1 Diabetes Mellitus

Corneal densitometry: A new evaluation indicator for corneal diseases

Corneal densitometry (CD) uses the biological properties of the cornea to visualize the morphology of the cornea and determine the degree of corneal transparency. At present, it is an emerging metric that has shown promise in various clinical diagnosis and evaluation of eye diseases and surgeries. We introduce the different methodologies used to measure CD. Furthermore, we systematically categorize the diagnostic value of CD into high, medium, and low levels based on its clinical significance. By analyzing a wide range of conditions, including keratoconus, postrefractive surgery changes, and other corneal pathologies, we assess the utility of CD in each context. We also discuss the potential implications of these classifications for disease monitoring and prognosis evaluation. Our review underscores the importance of integrating CD assessments into routine clinical practice to enhance the accuracy and effectiveness of diagnostic processes for corneal disorders.

Effect of smoking on corneal and lens clarity: a densitometric analysis

PURPOSE

To assess the effect of chronic cigarette smoking on corneal and lens densitometry measurements using Pentacam HR and to compare the results obtained with those in non-smokers.

MATERIALS AND METHODS

This cross-sectional comparative study included 40 chronic-smokers and 40 age-matched healthy non-smokers between 18-40 years. After general ophthalmic examination, the Pentacam HR imaging system was used to evaluate corneal and lens densitometry measurements of smokers and non-smokers.

RESULTS

The mean corneal densitometry values were not statistically significantly different in all the concentric zones and layers in the eyes of the smokers and non-smokers (p > 0.05, for all). However, the mean values of zone 1, zone 2, zone 3 and average lens densitometry measurements of the smokers were statistically significantly higher compared to non-smokers (p < 0.05, for all). Additionally, significant positive correlations were detected between the number of pack-years smoked and lens densitometry measurements.

CONCLUSION

Lens densitometry measurements of smokers were significantly increased while corneal densitometry measurements were not significantly altered compared to non-smokers. Smoking may contribute to cataractogenesis and smoking and age-related changes may act synergistically to cataract development among smokers.

Analysis of Corneal and Lens Densitometry Changes in Patients With Type 1 Diabetes Mellitus

PURPOSE

By comparing the densitometry findings of patients with type 1 diabetes mellitus (T1DM) and the healthy group, we aimed to understand the possible changes that may occur in the cornea and lens in those with diabetes mellitus (DM).

DESIGN

Prospective, cross-sectional study.

METHODS

A total of 60 eyes of 60 patients with T1DM and 101 eyes of 101 healthy subjects were included in this study. A complete ophthalmologic evaluation was performed in all participants. Scheimpflug tomography was performed to record the corneal and lens densitometry and other tomographic data. Mean glycosylated hemoglobin (HbA1c) and mean DM duration were recorded.

RESULTS

The mean age of the patients with T1DM and patients in the control group was 29.93 ± 8.56 years and 27.27 ± 1 4.96 years, respectively. The mean HbA1c was 8.43 ± 1.92, and the mean DM duration was 14.10 ± 7.77 years. Corneal densitometry (CD) values were significantly higher in the 0- to 2-mm zone in all layers and in the anterior and central 6- to 10-mm zone in the diabetic group (P = .03, P = .018, P = .001, P = .000, P = .004). The mean crystalline lens densitometry was higher in the T1DM group (P = .129). There were positive correlations between DM duration and CD in the anterior 0- to 2-mm (P = .043), central 6- to 10-mm (P = .016), posterior 6- to 10-mm (P = .022), and posterior 10- to 12-mm zone (P = .043).

CONCLUSIONS

CD values were significantly higher in the diabetic group. Diabetes duration and HbA1c values showed correlations with densitometry especially in the 6- to 10-mm corneal zone. Evaluation of the cornea with optical densitometry will be useful in the early diagnosis and follow-up of clinical structural and functional changes in the cornea.

Choroidal thickness and choroidal vascularity index changes in children with type 1 diabetes mellitus without retinopathy

BACKGROUND

Diabetic retinopathy is one of the most important causes of low vision in the working age group. Retinopathy findings start earlier and have a worse prognosis in type 1 DM. The aim of the this study was to compare the choroidal thickness (CT) and choroidal vascular index (CVI) values of type 1 diabetes mellitus (DM) patients without retinopathy findings in pediatric patients and healthy children.

METHODS

The study included 89 children, including 43 type 1 DM patients and 46 healthy controls. The age, gender, duration of DM, hemoglobin A1c (HbA1c), refractive error, intraocular pressure (IOP) and axial length (AL) of the participants were noted. CT measurements were performed subfoveally, 1000 µm from the fovea in the nasal and temporal quadrants. The total choroidal area (TCA), luminal area (LA) and stromal area (SA) were calculated using the binarization method using the image J program. The CVI was determined by dividing the luminal area by the total choroidal area.

RESULTS

There were no significant differences between the participants in terms of age, gender, spherical equivalent, IOP, and AL. There was no significant difference between the groups in terms of CT. TCA, LA and SA values were significantly higher in the Type 1 DM group (p=0.034, p=0.036, p=0.037, respectively). There was no significant difference between the groups in terms of the CVI.

CONCLUSIONS

The TCA, LA, and SA values were significantly higher in the type 1 DM group. LA/SA and CVI values were lower in the type 1 DM group, although not significantly. There was a negative correlation between the duration of DM and LA/SA as well as CVI. This suggests that vascular reduction starts in the early stages.

Corneal and lenticular clarity in children with inflammatory disease as assessed by Scheimpflug imaging

BACKGROUND

Corneal and lenticular optical properties are not well-documented in pediatric patients with inflammatory diseases. Here we aimed to evaluate corneal and lenticular optical density as well as corneal morphology in children with ocular and/or systemic inflammation by Scheimpflug imaging.

METHODS

Fifty-five eyes of 29 children with non-infectious uveitis, 56 eyes of 28 children with systemic inflammation without uveitis and 60 eyes of 31 healthy children were included. Corneal/lenticular optical density, corneal volume, central corneal thickness, keratometry were analyzed by Pentacam HR. Corneal endothelial cell density, hexagonal cell ratio and coefficient of variation were measured by specular microscope.

RESULTS

The mean age was 12.0±3.1 years, 11.9±4.0 years and 11.3±3.4 years whereas the female/ratio was 15/14, 15/13 and 14/17 in uveitis, systemic inflammation and control groups respectively. Uveitis type was anterior uveitis in 16 (29.1%) eyes, intermediate uveitis in 32 (58.2%) eyes and panuveitis in 7 (12.7%) eyes. Twenty-two (40%) eyes had active uveitis whereas 33 (60%) eyes had inactive uveitis. Corneal optical density was greater in uveitis group compared with other groups (p=0.001, Kruskal-Wallis test). Lenticular density and corneal parameters other than optical density were not different between the groups (p>0.05). Corneal optical density was higher in active uveitis than inactive uveitis (22/33 eyes, p=0.017).

CONCLUSION

Children with uveitis had decreased corneal clarity compared with systemic inflammation group and healthy controls, while lenticular clarity was similar between the groups. Corneal endothelial parameters did not change significantly based on ocular/systemic inflammation. Scheimpflug imaging provides objective corneal and lenticular optical density measurements.

Corneal and lens densitometry in patients with vernal keratoconjunctivitis

AIM

To evaluate corneal and crystalline lens densitometry in patients with vernal keratoconjunctivitis (VKC).

METHODS

This is a case-control study. Patients with VKC and age-gender-matched healthy controls underwent a complete ophthalmologic examination with corneal and crystalline lens densitometry measurements. Additionally, the anterior chamber parameters comprise anterior and posterior K_mean and astigmatism, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), pachymeter, and corneal volume (CV). Patients who had clinically grade 0 or grade 1 VKC and with only tarsal conjunctiva involvement during the conductance of the study were included. The variables were compared statistically.

RESULTS

One hundred and nine eyes were included in the study, in which fifty-one were in the VKC group. There were 25 males in the VKC group (26 female) and 22 males in the control group (36 female). A statistically significant difference was found between the groups in terms of posterior corneal astigmatism (p = 0.02). The mean corneal pachymeter, CV, ACD, ACA, and ACV were similar in both groups (p = 0.63, p = 0.26, p = 0.60, p = 0.41, and p = 0.32, respectively). The total mean corneal densitometry in the zones extending from 6 to 10 mm and 10 to 12 mm was increased in the VKC group compared to the control group (p = 0.04 and p = 0.012, respectively). The mean crystalline lens was found to be denser in the VKC group compared to the control group (8.96 ± 1.6 vs. 8.5 ± 0.57, respectively, p = 0.04).

CONCLUSION

Posterior corneal astigmatism is increased in VKC cases in comparison with age- and gender-matched controls. The peripheral anterior 6-12 mm annular corneal zone showed increased corneal densitometry in VKC cases compared to the healthy subjects. Additionally, the lens clarity is found to be decreased subclinically in VKC cases compared to control cases.

Evaluation of anterior segment parameters with Pentacam in children with poorly-controlled type 1 Diabetes Mellitus without diabetic retinopathy

PURPOSE

To determine the effect of abnormal glucose metabolism on the cornea, lens, anterior chamber volume (ACV), and anterior chamber depth (ACD) in children with poorly-controlled type 1 diabetes mellitus (DM) without diabetic retinopathy (DR).

METHODS

After the complete ophthalmologic examination of children with poorly-controlled (glycosylated hemoglobin [HbA1c] >7.0 %) type 1 DM without DR and age-matched healthy subjects (control group), the central corneal thickness (CCT), keratometry (K) values (Kmean front and back, and Kmax), radius (R) values (Rmin front and back), corneal volume (CV), ACD, ACV, pupil diameter, mean lens density (MLD), lens density standard deviation (LD SD), and maximum lens density (LD max) were measured using Pentacam High Resolution. Endothelial cell density was measured using a specular microscope. The results were assessed and compared between the two groups.

RESULTS

There were 60 patients (38 boys and 22 girls) in the DM group and 30 (14 boys, 16 girls) in the control group. There were considerable differences between the groups in terms of CCT, CV, ACD, MLD, LD SD and LD max, and Kmean back. Further, there was a positive correlation between HbA1c and MLD, LD SD, CV, and CCT in patients with DM.

CONCLUSION

The results of our study demonstrate that poorly-controlled type 1 DM without DR affects the cornea, ACD, and LD based on anterior segment measurements taken with a Scheimpflug camera. CCT, CV, LD SD, and MLD values may be parameters that can be used to follow-up patients with type 1 DM.

Corneal Properties in Primary Open-angle Glaucoma Assessed Through Scheimpflug Corneal Topography and Densitometry

PURPOSE

The purpose of this study was to compare corneal topography and densitometry measurements in patients with primary open-angle glaucoma (POAG) and healthy subjects.

PATIENTS AND METHODS

A total of 200 eyes of 75 patients with POAG and 125 healthy controls underwent corneal topography and densitometry (Oculus Pentacam HR). The data compared in the 2 groups were: anterior chamber angle, anterior chamber depth, and anterior chamber volume, keratometry (Kminimum, Kmaximum, and Kmean), central corneal thickness, central anterior elevation, anterior elevation apex, maximum anterior elevation, and posterior elevation apex. Densitometry measurements were made at 3 depths on a 12-mm-diameter circle divided into 4 concentric rings (0 to 2, 2 to 6, 6 to 10, and 10 to 12 mm). The diagnostic capacity of the corneal variables was assessed through the areas under the receiver operating characteristics curve.

RESULTS

The corneal density of practically all depth layers and total corneal density were significantly higher in the POAG than the control group (P<0.05). Total corneal density was positively correlated with age (r=0.623; P<0.001) and also showed a good diagnostic capacity for glaucoma [area under the curve=0.617; 95% confidence interval (CI): 0.541-0.697; P<0.001]. In a multiple linear regression designed to assess its relationship with age, sex, central corneal thickness, and Kmean, age emerged as a significant confounder both in controls (coefficient=0.315; P<0.001; 95% CI: 0.246-0.384) and patients (coefficient=0.370; P<0.001; 95% CI: 0.255-0.486).

CONCLUSION

Corneal densitometry measurements showed a good diagnostic capacity for POAG suggesting this type of examination could have clinical applications in the diagnosis and management of glaucoma.

Corneal densitometry and topography in patients with primary congenital glaucoma

OBJECTIVE

To compare corneal densitometry and topography variables in patients with primary congenital glaucoma (PCG) and healthy subjects.

MATERIAL AND METHODS

Cross sectional study, consecutive recruitment with gender- and age-matched control group. Forty eyes of 40 patients in each group were studied with Pentacam corneal topography. The variables compared between the two groups were: intraocular pressure (IOP), visual acuity (VA) and Pentacam (Oculus, Wetzlar, Germany) corneal topography measurements: mean and maximum keratometry (Km, Kmax), cylinder (Cyl), anterior elevation apex (AEA), central anterior elevation (CAE), maximum anterior elevation (MAE), posterior elevation apex (PEA), central posterior elevation (CPE), maximum posterior elevation (MPE), pachymetry and anterior, mid-stromal and posterior corneal densitometry in the 0-2mm, 2-6mm, 6-10mm zones.

RESULTS

Significant differences between patients and healthy controls were detected in the topographic variables MAE (P=0.002) and MPE (P<0.001), and in all the densitometry variables (anterior, mid-stromal, posterior for the 0-2mm, 2-6mm and 6-10mm zones) (P<0.001 each). In the PCG group, negative correlation was observed between VA and total densitometry (r=-0.49; P=0.004).

CONCLUSION

Patients with PCG and healthy subjects display differences in corneal densitometry and topographic measurements. PCG patients show greater corneal density with an inverse relationship between visual acuity and higher elevation (anterior and posterior values).

Changes in Retinal Microcirculation Precede the Clinical Onset of Diabetic Retinopathy in Children With Type 1 Diabetes Mellitus

PURPOSE

To investigate whether abnormal glucose metabolism in diabetes mellitus (DM) affects the retinal microcirculation of children with well-controlled type 1 DM and to compare these results with those obtained from healthy children.

DESIGN

Cross-sectional prospective study.

METHODS

This study enrolled 60 patients with DM without clinically detectable diabetic retinopathy (DR) and 57 age-matched control subjects. Optical coherence tomography angiography (OCT-A) was performed using AngioVue (Avanti, Optivue). Foveal avascular zone (FAZ) area, nonflow area, superficial and deep vessel densities, FAZ perimeter, acircularity index of FAZ (AI; the ratio of the perimeter of FAZ and the perimeter of a circle with equal area), and foveal density (FD-300; vessel density in 300 μm around FAZ) were analyzed. Correlations between the investigated OCT-A parameters with DM duration and glycated hemoglobin (HbA1c) levels were evaluated among patients with type 1 DM.

RESULTS

Differences in the mean values for FAZ perimeter, AI, and FD-300 were statistically significant between DM group and control group (P < .001, P = .001, and P = .009, respectively). There were also statistically significant differences between the groups for vessel densities of deep superior hemi-parafovea, deep temporal parafovea, and deep superior parafoveal zones (P = .008, P = .015, and P = .005, respectively). There were no significant correlations between DM duration and HbA1c levels with the investigated OCT-A parameters.

CONCLUSION

Diabetic eyes without clinically detectable DR exhibited alterations in FD-300, AI, perimeter, and vessel density of parafoveal capillaries in deep capillary plexus preceding the enlargement of FAZ; therefore, these new parameters might be sensitive imaging biomarkers to define early DR.

An Update on Corneal Biomechanics and Architecture in Diabetes

In the last decade, we have witnessed substantial progress in our understanding of corneal biomechanics and architecture. It is well known that diabetes is a systemic metabolic disease that causes chronic progressive damage in the main organs of the human body, including the eyeball. Although the main and most widely recognized ocular effect of diabetes is on the retina, the structure of the cornea (the outermost and transparent tissue of the eye) can also be affected by the poor glycemic control characterizing diabetes. The different corneal structures (epithelium, stroma, and endothelium) are affected by specific complications of diabetes. The development of new noninvasive diagnostic technologies has provided a better understanding of corneal tissue modifications. The objective of this review is to describe the advances in the knowledge of the corneal alterations that diabetes can induce.

Influence of peripheral corneal relaxing incisions during cataract surgery for corneal astigmatism up to 2.5 dioptres on corneal densitometry

PURPOSE

To assess the effect of peripheral corneal relaxing incisions (PCRI) for astigmatism between 0.75 and 2.5 dioptres during cataract surgery on corneal densitometry (CD).

METHODS

In this prospective, randomised study, 80 eyes (80 patients), received either tIOL or PCRI. Assessment at pre-operative and 1, 3, 6, 12 months post-operative visit included uncorrected (UCDVA) and best-corrected distance visual acuity (BCDVA), spherical equivalent (SEQ) (only post-operatively), mean anterior and posterior keratometric astigmatism (K_A) and CD with Schiempflug system. CD was analysed in four concentric radial zones from centre to periphery (Zone 1 to 4) and in 3 layers (anterior, mid-stromal and posterior).

RESULTS

Comparing tIOLs vs. PCRIs, there was no significant difference in the UCDVA, BCDVA and SEQ. In PCRI group, anterior K_A decreased at 1 month and remained stable thereafter. For zones 1, 2 and 3, CD significantly reduced after 3 months with tIOLs whereas with PCRIs, it reduced 1 month onwards. For zone 4, CD reduced only at 12 months with tIOLs compared to 3 months onwards with PCRIs. In both groups CD was higher in the zone 4 and anterior layer. Significant reduction in CD was found in all three layers of cornea after 3 months in tIOL and after first month in PCRI groups, respectively.

CONCLUSIONS

Cataract surgery alone reduces the CD. Reducing keratometric astigmatism with PCRIs shows significant differences in CD from early post-operative period for central and anterior corneal layer.

Quantitative evaluation of early retinal changes in children with type 1 diabetes mellitus without retinopathy

BACKGROUND

To investigate whether abnormal glucose metabolism and duration of diabetes mellitus (DM) caused the thinning in retinal layers in children with type 1 DM without retinopathy by using spectral domain optical coherence tomography (SD-OCT) and to compare the results obtained with those in healthy children.

METHODS

This cross-sectional prospective study included 73 patients with type 1 DM (DM group) and 62 age-matched control subjects (control group). The duration of DM and the glycosylated haemoglobin (HbA1c) levels of the diabetic children were recorded. Macular and peripapillary retinal nerve fibre layer (RNFL) thickness measurements obtained by SD-OCT were compared.

RESULTS

There were significant differences in the mean values of the temporal inner, temporal outer and inferior outer macular thickness measurements between the groups (p = 0.031, p = 0.028 and p = 0.039, respectively). Moreover, the children with type 1 DM showed significantly thinner global, temporal superior and nasal inferior RNFL thickness measurements compared to the controls (p = 0.035, p = 0.022 and p = 0.034, respectively). Additionally, both the mean duration of DM and the mean HbA1c values were inversely and statistically significantly correlated with the mean temporal outer macular thickness and global RNFL thickness measurements in the DM group.

CONCLUSIONS

Retinal neural changes, which can be shown by SD-OCT, may be present in diabetic eyes even before clinically detectable retinal vasculopathy. Macular and RNFL thickness measurements might be useful indicators for early detection of diabetic retinopathy in the future.

Corneal Densitometry in Healthy Corneas and Its Correlation With Endothelial Morphometry

PURPOSE

To evaluate the correlations between corneal endothelial cell properties and corneal densitometry values and to investigate whether corneal densitometry may be used as an indicator of the health of corneal endothelium.

METHODS

Two hundred fifty-three eyes were analyzed in this prospective cross-sectional study. Corneal densitometry was measured with densitometry software of Pentacam HR-Scheimpflug corneal topography over a 12-mm diameter of the cornea. Furthermore, corneal endothelial cell properties including cell density (CD), average cell area, SD of the cell area, coefficient of variation (CV) of the cell area, maximum cell area, minimum cell area, and percentage of hexagonal cells (HEX) were measured by a specular microscope. The correlations were calculated using Pearson correlation tests.

RESULTS

The average cell area, SD, maximum cell area, and minimum cell area values were not statistically significantly correlated with the corneal densitometry values in any layer or concentric annulus. CD, CV, and HEX were statistically significantly correlated with the corneal densitometry values in all layers and concentric annuli (P < 0.05 for each one). Moreover, CD and HEX were inversely and moderately correlated with total corneal densitometry (r = -0.403, P < 0.001, and r = -0.327, P < 0.001, respectively), whereas the CV was positively and moderately correlated with total corneal densitometry (r = 0.349, P < 0.001).

CONCLUSIONS

Corneal densitometry might have potential to be used as an indicator of the health of corneal endothelium in the future.