Rat Model of Type 2 Diabetes Mellitus Recapitulates Human Disease in the Anterior Segment of the Eye.

Changes in the anterior segment of the eye due to type 2 diabetes mellitus (T2DM) are not well-characterized, in part due to the lack of a reliable animal model. This study evaluated changes in the anterior segment, including crystalline lens health, corneal endothelial cell density, aqueous humor metabolites, and ciliary body vasculature, in a rat model of T2DM compared with human eyes. Male Sprague-Dawley rats were fed a high-fat diet (45% fat) or normal diet, and rats fed the high-fat diet were injected with streptozotocin intraperitoneally to generate a model of T2DM. Cataract formation and corneal endothelial cell density were assessed using microscopic analysis. Diabetes-related rat aqueous humor alterations were assessed using metabolomics screening. Transmission electron microscopy was used to assess qualitative ultrastructural changes ciliary process microvessels at the site of aqueous formation in the eyes of diabetic rats and humans. Eyes from the diabetic rats demonstrated cataracts, lower corneal endothelial cell densities, altered aqueous metabolites, and ciliary body ultrastructural changes, including vascular endothelial cell activation, pericyte degeneration, perivascular edema, and basement membrane reduplication. These findings recapitulated diabetic changes in human eyes. These results support the use of this model for studying ocular manifestations of T2DM and support a hypothesis postulating blood-aqueous barrier breakdown and vascular leakage at the ciliary body as a mechanism for diabetic anterior segment pathology.

Indications for Wear, Visual Outcomes, and Complications of Custom Imprint 3D Scanned Scleral Contact Lens Use.

PURPOSE: To report indications for wear, visual outcomes, and complications of EyePrintPRO (EPP) scleral contact lens (SCL) use. METHODS: A retrospective review identified all patients fitted with this device between December 2013 and March 2018. Baseline demographics, wear indication, and contact lens history were determined. Habitual-corrected visual acuity was measured at baseline and follow-up. Adverse wear symptoms and signs, reprinting, and device cessation were tracked. RESULTS: Ninety-five eyes from 69 patients were followed for a median of 12.1 months (interquartile range 4.4-19.6). Indications for wear included vision improvement and/or ocular surface stabilization in the setting of irregular corneal shape (n = 68 eyes, 72%), ocular surface disease (n = 17, 18%), exposure keratopathy (n = 7, 7%), neurotrophic keratitis (n = 5, 5%), and extracorneal topographical abnormalities preventing noncustom lens fitting such as glaucoma drainage devices (n = 8, 8%). Median habitual-corrected visual acuity improved from 0.67 to 0.08 (P = 0.0003). One-third of eyes (33.1%) developed adverse wear symptoms. Fifteen of 95 eyes (16%) developed adverse wear signs. Device cessation occurred in 10 eyes (10.5%) and reprinting occurred in 14 eyes (14.7%) unrelated to prior lens wear or indication (P = 0.67 and 0.15, respectively). In eyes that previously failed SCLs (n = 56), 12 eyes required reprinting and 49 eyes continued use. CONCLUSIONS: Indications for EPP wear include irregular corneal shape, ocular surface disease, and extracorneal topographic abnormalities. Visual acuity improves with the use of EPP. Clinicians and patients should be aware of potential adverse wear symptoms/signs and device cessation that may occur with EPP use. EPP is a viable salvage therapy in eyes that previously failed SCLs.

Transcorneal Cryotherapy and Descemet Membrane Endothelial Keratoplasty to Treat Epithelial Downgrowth and Corneal Decompensation After Cataract Surgery.

PURPOSE: Epithelial downgrowth is a vision-threatening complication of intraocular surgery or penetrating ocular trauma, and although various therapeutic interventions have been performed to treat this disease, success has been limited. We present a case of corneal decompensation secondary to epithelial downgrowth after uncomplicated clear corneal cataract surgery in the left eye, treated successfully with sequential transcorneal cryotherapy to destroy epithelial cell nests followed by Descemet membrane endothelial keratoplasty (DMEK) to restore corneal clarity and vision. METHODS: We applied a transcorneal cryotherapy probe using a double freeze-thaw technique at -80°C to the entire cornea, with care taken to spare the limbus except at the superior temporal quadrant overlying the clear corneal incision where treatment was applied intentionally. The same procedure was performed 2 weeks later to ensure complete ablation of epithelial nest cells. Uncomplicated DMEK surgery using standard technique was performed 1 week later to restore corneal clarity. RESULTS: Visual acuity at presentation was 20/40. Endothelial cell densities were 2138 cells/mm (22% loss) and 1720 cells/mm (37% loss) at 3- and 12-months after DMEK, respectively. Two years after surgery, the best-corrected visual acuity remained 20/20 and the patient had no evidence of recurrence or limbal stem cell deficiency. CONCLUSIONS: The use of sequential cryotherapy as a targeted intervention to destroy invasive corneal epithelial cells followed by staged DMEK surgery to replace damaged corneal endothelium was, in this case, an effective treatment for endothelial decompensation secondary to epithelial downgrowth and may be a potential alternative for the management of this disease.