Topical aldose reductase inhibitor for correcting corneal endothelial changes in diabetic patients

Clinical evaluation of corneal changes after phacoemulsification in diabetic and non-diabetic cataract patients, a systematic review and meta-analysis

Corneal endothelium morphological abnormalities result in fluid imbalance, stromal swelling, and loss of transparency, thus impairing visual function. Recently, growing number of studies have focused on diabetic corneal abnormalities after cataract surgery and its comparison with non-diabetic patients, the results remain conflicting. Thus, to evaluate the effect of phacoemulsification on the corneal properties in diabetic and non-diabetic patients, prospective studies were comprehensively searched through PubMed, EMBASE, and Cochrane databases updated to Jan 2017. A meta-analysis of the 13 identified studies was performed using weighted mean difference (WMD) and 95% confidence interval (CI). For the dynamic changes between preoperative and postoperative values, significant differences were identified between the two groups in endothelial cell density (ECD) and hexagon cells (HC%) at 1 day, 1 week, 1 month, and 3 months postoperatively, in central corneal thickness (CCT) at 1 month postoperatively, and in coefficient variation (CV) at 1 week and 1 month postoperatively. However, no significant differences were observed in CCT at 1 day, 1 week and 3 months postoperatively or in CV at 1 day and 3 months postoperatively. Diabetic corneas are more vulnerable to stress and trauma, resulting in greater morphological abnormalities and longer recovery time.

Refractive surgery in systemic and autoimmune disease

Patients with underlying systemic disease represent challenging treatment dilemma to the refractive surgeon. The refractive error in this patient population is accompanied by a systemic disease that may have an ocular or even a corneal component. The literature is rather sparse about the use of laser refractive surgery (LRS) and such procedure is not approved by the United States Food and Drug Administration (FDA) in this patient population. Patients with collagen vascular disease, diabetes mellitus (DM), allergic and atopic disease, or human immunodeficiency virus (HIV) are never ideal for LRS. Patients with uncontrolled systemic disease or ocular involvement of the disease should not undergo LRS. However, a patient with well-controlled and mild disease, no ocular involvement, and not on multidrug regimen may be a suitable candidate if they meet stringent criteria. There is a need for a large, multicenter, controlled trial to address the safety and efficacy of LRS in patients with systemic disease before such technology can be widely adopted by the refractive surgery community.

Evaluation of corneal endothelium in children and adolescents with type 1 diabetes mellitus

Purpose. To evaluate the systemic and local factors that contribute to the damage of endothelial cells in diabetic patients and to compare the endothelial structure of the cornea in diabetic and nondiabetic patients. Materials and Methods. The endothelial cell density (ECD) and central corneal thickness (CCT) were investigated in 123 eyes of type 1 diabetic patients and in 124 eyes of nondiabetic patients. The mean diabetic patients age was 15.34 ± 3.06 years versus 14.58 ± 2.01 years in the control group. The mean duration of diabetes was 8.02 ± 3.9 years. The corneal endothelium was imaged by the Topcon SP-2000P. Results. The mean ECD in diabetic eyes was 2435.55 ± 443.43 cells/mm² and was significantly lower than in control group (2970.75 ± 270.1 cells/mm²). The mean CCT was 0.55 ± 0.03 mm in diabetic group versus 0.53 ± 0.033 mm in control group. ECD and CCT significantly correlated only with duration of diabetes. There was no correlation between ECD and CCT and patient age, sex, HbA1C level, and plasma creatinine level. Conclusions. ECD is decreased and CCT is increased in children and adolescents with diabetes mellitus. Duration of diabetes is the factor that affects ECD and CCT.

Laser refractive surgery in diabetic patients: a review of the literature

BACKGROUND

The purpose of this study was to evaluate the current recommendations regarding laser refractive surgery in patients with diabetes mellitus and to assess whether these patients make appropriate candidates for laser vision correction.

METHODS

A literature search was conducted to identify current research on the ocular complications of diabetes and original publications on laser refractive surgery in diabetic patients.

RESULTS

Diabetes was associated with several ocular complications. Initially the US Food and Drug Administration listed these complications as justification to advise against refractive surgery in patients with diabetes. However, recent studies on laser in situ keratomileusis in diabetic patients indicate that this procedure may be safe in diabetic patients with very well controlled systemic disease and no ocular manifestations.

CONCLUSION

Laser refractive surgery may be performed safely in a very selected group of patients with diabetes.

The effect of topical autologous serum on graft re-epithelialization after penetrating keratoplasty

PURPOSE

To analyze factors influencing corneal graft re-epithelialization after penetrating keratoplasty (PK) and evaluate the effect of topical autologous serum in promoting graft re-epithelialization.

DESIGN

Prospective interventional study.

METHODS

We analyzed 165 eyes of 165 patients who underwent PK between January 1, 2005 and December 31, 2007. Patients were divided into 2 groups according to routine use or non-use of postoperative 20% topical autologous serum. Postoperative slit-lamp examination after fluorescein staining was performed, and graft re-epithelialization time was recorded. Recipient/donor characteristics, surgical variables, and topical use of autologous serum were analyzed for their effects on post-PK graft re-epithelialization. Statistical analysis was performed by univariate and multivariate regression analysis using the ordinal logistic fit model to assess the potential risk factors influencing graft re-epithelialization after PK.

RESULTS

In univariate analysis, diabetes mellitus (DM), longer death-to-storage time and death-to-surgery time of the donor, and larger recipient size significantly delayed graft re-epithelialization (P < .05). Use of autologous serum significantly expedited graft re-epithelialization (P = .004). In multiple regression analysis, only DM in the recipient (odds ratio [OR] = 5.10, P < .001), postoperative use of autologous serum (OR = 0.54, P = .046), and larger graft size (OR = 4.44, P < .001) influenced graft re-epithelialization. The beneficial and healing effect of autologous serum is particularly significant in diabetic recipients and larger grafts.

CONCLUSIONS

Several factors may influence graft re-epithelialization after PK. Graft re-epithelialization time was longer in diabetic recipients and larger grafts. Use of autologous serum may be a beneficial strategy in these patients with potentially delayed epithelial healing.

In vivo confocal microscopic findings of corneal wound healing after corneal epithelial debridement in diabetic vitrectomy

PURPOSE

To study healing of corneal wounds using in vivo confocal microscopy in patients who received corneal epithelial debridement during pars plana vitrectomy for proliferative diabetic retinopathy and to investigate risk factors for delayed healing.

DESIGN

Prospective, observational case series.

PARTICIPANTS

Forty-four eyes of 40 patients were enrolled.

METHODS

In vivo confocal microscopy was used to evaluate selected images of the corneal basal and apical surface epithelial cells and subbasal nerves before surgery, weekly for the first month, and at 3 and 6 months after surgery. Slit-lamp biomicroscopy was carried out at the same time. Multiple linear regression analysis of selected potential risk factors was performed to investigate the main determinants of delayed corneal healing.

MAIN OUTCOME MEASURES

Healing rate of corneal epithelial cells and subbasal nerves and factors influencing the healing.

RESULTS

By slit-lamp biomicroscopy, corneal epithelial defects were found in 22.8% of eyes at 2 weeks and in 5.4% at 1 month after surgery. In vivo confocal microscopy demonstrated incomplete healing of basal epithelial cells in 72.1%, 15.2%, and 0% of eyes and incomplete healing of surface apical epithelial cells in 81.1%, 9.1%, and 0% of eyes at 1, 3, and 6 months after surgery. The percentage of subbasal nerves regaining preoperative appearance was 0%, 6.8%, and 89.3% at 1, 3, and 6 months after surgery. Regression analysis revealed infusion of silicone oil (P = 0.020) and C(3)F(8) (P = 0.017) resulted in delayed healing by slit-lamp biomicroscopy; age (P = 0.028), diabetic treatment regimen (P = 0.014), and scleral buckling (P = 0.001) correlated with delayed recovery of basal cells by in vivo confocal microscopy. The latter 2 factors also were related to delayed reconformation of apical cells (P = 0.011 and 0.004, respectively). Neither healing of apical and basal cells showed a significant correlation to findings by slit-lamp biomicroscopy (r = 0.19 and 0.09).

CONCLUSIONS

Healing of corneal epithelial wounds in diabetic eyes is slow. Both the basal and apical epithelial layers were involved in the slow healing process. Age, diabetic treatment regimen, and several intraoperative factors may alter healing rates.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Change in long-spacing collagen in Descemet's membrane of diabetic Goto-Kakizaki rats and its suppression by antidiabetic agents

We examined changes in the ultrastructure and localization of major extracellular matrix components, including 5 types of collagen (type I, III, IV, VI, and VIII), laminin, fibronectin, and heparan sulfate proteoglycan in Descemet's membrane of the cornea of diabetic GK rats. In the cornea of diabetic GK rats, more long-spacing collagen fibrils were observed in Descemet's membrane than in the membrane of the nondiabetic Wistar rats. Both GK and Wistar rats showed an age-dependent increase in the density of the long-spacing collagen. Immunoelectron microscopy showed that type VIII collagen was localized in the internodal region of the long-spacing collagen, which was not labelled by any of the other antibodies used. The antidiabetic agents nateglinide and glibenclamide significantly suppressed the formation of the long-spacing collagen in the diabetic rats. Long-spacing collagen would thus be a useful indicator for studying diabetic changes in the cornea and the effect of antidiabetic agents.

Morphologic alterations of both the stromal and subbasal nerves in the corneas of patients with diabetes

PURPOSE

To evaluate the subbasal and the stromal nerves of the corneas of patients with type 2 diabetes with in vivo confocal microscopy and to compare them with those of nondiabetic patients.

METHODS

Thirty-five corneas of patients with type 2 diabetes and 24 corneas of age-matched control subjects were included in the study. Patients with diabetes were further classified with respect to the stage of retinopathy. Subbasal and stromal nerve plexus morphology and thickness were evaluated with in vivo confocal microscopy. Subbasal long nerve fiber (LNF) and total nerve branch (NB) densities were calculated.

RESULTS

The mean stromal nerve thickness was significantly higher in patients with diabetes (8.99 +/- 2.32 microm) than that of the control subjects (5.69 +/- 1.49 microm; Mann-Whitney U test; P < 0.001). The proportion of curved stromal nerves in patients with diabetes (45.7%) was also higher than that of normal subjects (20.8%; chi(2), P = 0.05). Subbasal LNF and NB densities were found to significantly lower in the corneas of patients with diabetes (28.3 +/- 10.4 and 39.7 +/- 13.2 nerve/mm(2), respectively) than those of the control subjects (34.1 +/- 5.7 and 58.5 +/- 12.4 nerve/mm(2), respectively; Mann-Whitney, P = 0.012 and P < 0.001). In addition, the subbasal nerve plexus of patients with diabetes appeared significantly thicker and more tortuous than those of the control subjects (Mann-Whitney, P = 0.002 and P = 0.001).

CONCLUSION

Both stromal and subbasal nerves appear abnormal in the corneas of patients with diabetes. Patients with proliferative diabetic retinopathy show more pronounced nerve alterations than patients who do not have diabetic retinopathy.

Preparation of stable aqueous suspension of a hydrophobic drug with polymers

Pharmaceutical preparation of a hydrophobic aldose reductase inhibitor 5-(3-ethoxy-4-pentyloxyphenyl)-2,4-thiazolidinedione (CT112) was investigated. CT112 dissolved in a basic solution with different kinds of polymers was neutralized by acid to obtain a suspension preparation. In particular, the addition of a polymer, hydroxypropyl methyl cellulose (HPMC) provided a stable CT112 suspension with a homogeneous particle size, and there seemed to be an optimal concentration of HPMC for the stable suspension. The addition of polysorbate 80 brought higher CT112 solubility in water, but did not provide a stable suspension. X-ray diffraction, IR spectrum, and thermal analysis revealed that the particles in the suspension with HPMC had lower degree of crystallinity, less hydrophobic particle surface, and lower melting point and decreased fusion enthalpy than the suspension without HPMC. These results suggested that the highly stable CT112 suspension could be attained by the adsorption of the polymer.

Corneal Endothelial Cell Morphometry and Corneal Thickness in Diabetic Contact Lens Wearers

PURPOSE

To assess corneal endothelial cell morphometry and corneal thickness in diabetic patients who wear contact lenses.

METHODS

Images of the central corneal endothelium were analyzed quantitatively and qualitatively and corneal thickness was measured in a group of diabetic patients (type 1, N = 26; type 2, N = 4) who wear soft contact lenses and in a group of nondiabetic age-matched control subjects who were also contact lens wearers.

RESULTS

Endothelial cell characteristics and corneal thickness values were similar for the two groups (p > 0.05). Four of the diabetic patients (and none of the nondiabetic patients) displayed folds in the endothelial mosaic.

CONCLUSIONS

The morphometry of corneal endothelial cells and central corneal thickness values in diabetic patients who wear soft contact lenses were not appreciably different from those found in lens-wearing control subjects.

Corneal sensitivity in dogs with diabetes mellitus

OBJECTIVE

To compare aesthesiometer-determined corneal sensitivity between diabetic and nondiabetic dogs and to investigate the correlation between corneal sensitivity and duration of diabetes or status of glycemic control, as estimated by use of glycated blood protein concentrations.

ANIMALS

23 diabetic and 29 nondiabetic normoglycemic dogs.

PROCEDURE

A Cochet-Bonnet aesthesiometer was used to measure corneal touch threshold (CTT) in 5 corneal regions of each dog. At the time of ocular examination, duration of diabetes mellitus was estimated from the history, and blood was drawn for assessment of blood glycosylated hemoglobin and serum fructosamine concentrations.

RESULTS

Median CTT for central, nasal, dorsal, temporal, and ventral corneal regions in nondiabetic dogs (1.6, 2.3, 2.8, 2.8, and 5.1 g/mm2, respectively) was significantly lower than in diabetic dogs (2.8, 4.0, 5.1, 5.1, and 6.6 g/mm2, respectively). Median regional CTT in diabetic dogs was not significantly correlated with estimated duration of diabetes mellitus or blood glycated protein concentrations. No significant difference was found in regional CTT between eyes of normoglycemic dogs with unilateral cataracts.

CONCLUSIONS AND CLINICAL RELEVANCE

Diabetic dogs have significantly reduced corneal sensitivity in all regions, compared with nondiabetic normoglycemic dogs. Regional variation in corneal sensitivity is similar in diabetic and normoglycemic dogs. Neither glycemic control nor duration of diabetes, as estimated, is significantly correlated with corneal hyposensitivity. Corneal nerve dysfunction may be associated with recurrent or nonhealing ulcers in diabetic dogs for which no other underlying cause can be found.