Kyong Jin Cho

Glial cell response and iNOS expression in the optic nerve head and retina of the rat following acute high IOP ischemia–reperfusion

Acute high IOP ischemia-reperfusion induces the loss of retinal ganglion cells, supporting the hypothesis that the condition of ischemia-reperfusion contributes to the induction and progression of glaucoma. This study investigated morphological changes, glial cell response, and expression of inducible nitric oxide synthase (iNOS) in the optic nerve head and retina of the rat following acute high IOP ischemia-reperfusion. A 60-min ischemic period was administered to the rat eye by raising the IOP, followed by a reperfusion period lasting 2, 5, or 7 days. Histological examination showed that acute high IOP ischemia-reperfusion injury produced optic nerve head and retina damage. In immunohistochemical staining, GFAP and OX-45 were limited to the ganglion cell layer (GCL) or inner nuclear layer (INL) of the control retina and increased to nearly all layers of the retina after acute high IOP ischemia-reperfusion. GFAP and OX-42 were detected at the control optic nerve heads and increased after acute high IOP ischemia-reperfusion. After acute high IOP ischemia-reperfusion, expression of iNOS increased, mostly at the GCL and INL of the retina and at the optic nerve head. Western blot analysis showed that expression of iNOS increased significantly, compared with the control, in the retina and optic nerve head after acute high IOP ischemia-reperfusion. Activation of glial cells and the up-regulation of iNOS may contribute to the damage of the retina and optic nerve head of the rat following acute high IOP ischemia-reperfusion.

Changes in corneal sensation and ocular surface in patients with asymmetrical keratoconus.

Purpose: To describe tear function, ocular surface changes, and corneal sensitivity in patients with asymmetrical keratoconus (KC). Methods: Thirty-one patients with asymmetrical KC (31 KC and 31 subclinical KC eyes) and 30 control subjects (1 eye in each subject) were enrolled in this prospective, case-control study. The patients and control subjects underwent ocular surface examinations including corneal sensitivity measurements, the Schirmer test using topical anesthesia, tear osmolarity test, and conjunctival impression cytology. Results: Mean corneal sensitivity and Schirmer test values were significantly lower in the KC and subclinical KC eyes compared with the control eyes. The conjunctiva of KC and subclinical KC eyes showed significantly higher grades of squamous metaplasia and goblet cell loss compared with the control group. However, no significant difference in tear osmolarity was found among the groups. Conclusions: The corneal sensitivity and ocular surface changes were significant in the subclinical KC and KC eyes compared with the control subjects. Ocular surface disease in KC was characterized by tear deficiency disorder and abnormal impression cytology results. However, no significant difference in tear osmolarity was found among the groups. The decrease in corneal sensitivity and ocular surface change may be associated with the pathogenesis of ocular surface changes in KC and the progression of the disease.

Surgical Outcomes of Transconjunctival Anterior Orbitotomy for Intraconal Orbital Cavernous Hemangioma

Purpose To describe surgical outcomes for transconjunctival anterior orbitotomy for intraconal cavernous hemangiomas. Methods The medical records of 9 consecutive patients with intraconal cavernous hemangiomas who underwent surgical removal by transconjunctival anterior orbitotomy were retrospectively reviewed. The conjunctiva was incised and retracted with a traction suture. For large tumors, a rectus muscle was temporarily disinserted. Tenons capsule was separated and the tumor was removed with a cryoprobe or clamp. Surgical outcomes, positions of the tumors, methods of approach, and intra- and post-operative complications were evaluated. Results The mean follow-up period was 33 ± 6.8 months. No bony orbitotomy was used in this technique and the cosmetic results were very satisfactory. All tumors were removed intact. In 4 patients, tumors were extirpated with the aid of a cryoprobe. No patients had residual proptosis or limitation of ocular movement. No signs of recurrence were noted in any cases at 33 months follow-up. No serious or permanent complications were observed during or after the operation. Conclusions Transconjunctival anterior orbitotomy is an important surgical procedure in the treatment of intraconal cavernous hemangiomas. It can produce an excellent result, even if the posterior border of the tumor abuts the orbital apex.

Association Between Corneal Endothelial Cell Density and Topical Glaucoma Medication Use in an Eye Bank Donor Population

Purpose: To evaluate the association between corneal endothelial cell density (ECD) and donor topical glaucoma medication use in an eye bank database. Methods: Raw eye bank data included 19,159 donors over the period July 2007 to May 2015. Free-text, donor medication lists were retrospectively searched for glaucoma medication. Exclusion criteria were age less than 40 years, history of eye surgery, endothelial trauma, guttae, and cell densities <1000 or >3300/mm2. Analysis of covariance was used to test differences in cell density between groups while adjusting for age. Linear regression was used to test the correlation of independent interval variables while adjusting for age. Results: Twelve thousand one hundred fifty-seven donors were included in the final analysis; 134 were on topical glaucoma medication. The mean ECD for donors not on glaucoma medication and pooled donors on glaucoma medication was 2561 ± 348 and 2516 ± 320 cells/mm2, respectively (P = 0.42). Subgroup analysis by medication class resulted in nonstatistically significant differences between ECDs of nonmedicated donors and donors on alpha agonists (P = 0.76), beta blockers (P = 0.90), carbonic anhydrase inhibitors (P = 0.13), cholinergics (P = 0.37), and prostaglandin analogs (P = 0.62). The number of glaucoma medication classes used by donors was not a statistically significant predictor of endothelial density (P = 0.298). Conclusions: Donors on topical glaucoma medication do not have ECDs statistically significantly lower than donors not on medication.