ABSTRACT
AIM: To compare the corneal backward light scattering values in type 2 diabetes mellitus (DM) patients with those of age and sex-matched healthy controls. METHODS: The study included 30 patients (30 eyes) with type 2 DM and 30 control subjects (30 eyes). Duration of diabetes, most recent hemoglobin A1c levels, along with the status of diabetic retinopathy, and existing medical treatment of all subjects were recorded. All subjects underwent a complete ophthalmologic examination. In addition, backward light scattering (densitometry) was measured to assess changes in corneal transparency using tomography (Pentacam HR). RESULTS: The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females. The age was 50.40±7.80y (range: 40-68y) of the diabetic group and 49.30±9.50y (rang: 40-73y) of control group. The diabetic group demonstrated significantly higher mean densitometry values of the anterior (6-10 mm) zone (P=0.047), the total anterior layer (P=0.036) and the total cornea (P=0.043) than control group. The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration. CONCLUSION: Diabetic group has higher densitometry in anterior corneal (6-10 mm) zone, total anterior cornea, and total cornea and with no correlation with hemoglobin A1c levels and DM duration.
ABSTRACT
PURPOSE: This study was conducted to evaluate the effects of long-term use of rigid gas-permeable (RGP) contact lenses on corneal endothelium in keratoconus (KC) patients using non-contact specular microscopy. In addition, the correlation between wearing duration of RGP lenses (years & hours /d) and endothelial morphometric changes in KC patients was performed. This may provide more useful data for clinical application of RGP contact lens. STUDY DESIGN: This study was a prospective, observational, comparative, hospital based, nonrandomized, cross-sectional, and quantitative study. SUBJECTS AND METHODS: The study included 40 eyes of non-wearer contact lens KC patients (group 1) and 38 KC eyes with a long history of Rose K2 RGP contact lens wearing (group 2). The corneal endothelial morphology such as endothelial cell density (ECD); coefficient of variation of cell area (CV); percentage of hexagonal cells (HEX); and central corneal thickness (CCT) were evaluated in all patients using SP3000P Specular Microscope. RESULTS: The study included 40 eyes of non-wearer contact lens KC patients (20 mild KC eyes and 20 moderate KC eyes) and 38 KC eyes with a long history of RGP contact lens wearing (18 mild KC eyes and 20 moderate KC eyes). The mean duration of RGP lenses wearing was 5.67 ± 3.481 years & 12.11 ± 2.698 h/d in mild KC eyes and 7.15 ± 5.294 years &13.65 ± 2.889 h/d in moderate KC eyes. Wearing duration in hours in mild KC eyes showed a significant moderate negative correlation with ECD (r = -0.529, p = 0.024) and a moderate positive correlation with CV (r = 0.565, p = 0.015). In addition, wearing duration in years in moderate KC eyes showed a significant moderate negative correlation with ECD (r = -0.465, p = 0.039) and moderate positive correlation with CV (r = 0.627, p = 0.003). However, wearing duration in hours in moderate KC eyes showed a significant moderate negative correlation with HEX only (r = -0.490, p = 0.028). This study reported significant corneal thinning in contact lens wearer KC eyes in contrast to non-wearer KC eyes. CONCLUSION: This study documented a significant correlation between a long-term use of Rose K2 RGP using the three-point touch and corneal endothelial morphometric changes in KC patients. In addition, the current study confirmed a significant corneal thinning in RGP contact lens wearer compared to non-contact lens wearer KC patients. Further studies are recommended to evaluate the association between different RGP lens materials with different oxygen permeability transmissibility; different lens design types; different fitting methods; the duration of contact lens wear and the endothelial morphometric changes in KC patients.
