Can Corneal Biomechanical Properties Give Clues About Elasticity of Optic Nerve Scleral Component in Nonarteritic Anterior Ischemic Optic Neuropathy?

OBJECTIVE: To investigate corneal biomechanical properties among individuals with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) compared to healthy gender- and age-matched subjects. METHODS: The study subjects were separated into 2 groups: 66 eyes of 33 patients with unilateral NAION (study group) and 33 eyes of 33 healthy individuals (control group). Reichert ocular response analyzer (Reichert Ophthalmic Instruments) was used to assess corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure values. Also, central corneal thickness was measured using Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; Costruzioni Strumenti Oftalmici). RESULTS: Mean CH and median CRF values were significantly lower in the affected eyes (8.8 ± 1.8 mm Hg, 9.4 mm Hg, respectively) and contralateral unaffected eyes (9.1 ± 1.6 mm Hg, 9.8 mm Hg, respectively) of NAION patients than those in the control group (9.9 ± 1.3 mm Hg, 10.4 mm Hg, respectively; all P < 0.017). Mean IOPcc was significantly higher in the affected eyes of NAION patients (19.2 ± 3.5 mm Hg) than in the eyes of control group (17.1 ± 3.6 mm Hg; P = 0.002). CONCLUSIONS: CH and CRF are significantly reduced in patients with NAION, possibly indirectly reflecting structural weakness in the lamina cribrosa.

Time course of silicone oil emulsification.

PURPOSE: To investigate the natural course of silicone oil emulsification after silicone oil tamponade usage in retinal detachment surgery. The presence of a group of patients whose silicone oil tamponades we preferred to keep as long as possible because of high risk of redetachment enabled us to investigate the course of in vivo silicone oil emulsification. METHODS: Thirty-two cases that were considered to have a high risk of redetachment after silicone oil removal were closely monitored, and it was preferred to keep the silicon oil as long as possible until first signs of silicone oil emulsification were observed. Any ocular complication directly related to the silicone oil tamponade did not arise in any of these cases, and the only indication for silicone oil removal was the signs of emulsification. RESULTS: The silicone oil emulsification time ranges from 5 months to 24 months with a mean of 13.2 ± 4.8 months. In most cases, it occurs within the first year. However, there are also 2 cases where emulsification is not observed until the 24th month. CONCLUSION: It could be possible to extend the silicone oil removal time up to 1 year to achieve a stable retinal status in cases with a high risk of redetachment.