The present study investigated the potential protective effects of cerium oxide nanoparticles (CNP) on human retinal pigment epithelium (ARPE-19) cells damaged by hydroxychloroquine (HCQ). Toxicity of HCQ on the ARPE-19 cells was explored with a dose response trial. CNP rescue both a pre-treatment protocol, where CNP were applied 24 hours prior to HCQ application and a simultaneous treatment protocol where both CNP and HCQ were applied together, were used. In the dose response trial, 250 µM HCQ showed 51.84% cell viability after 24 hours and 32.75% after 48 hours time period. This was selected as model HCQ dose for rescue trials. The simultaneous treatment trials did not show a significant increase in viability compared to model toxic dose. The CNP pre-treatment trials showed a significant increase in cellular viability compared to model toxic dose with 68.03% ± 3.27 viability (p = 4.56E−05) at 24 hours and 51.85% ± 4.96 (p = 1.18E−05) at 48 hours time period. CNP pre-treatment showed significant protection of cells from HCQ induced toxicity. The difference in efficacy of simultaneous and pre-treatment is hypothesized to lie in the cellular localization of CNP. Furthermore, including the reactive oxygen species (ROS) scavenging properties of CNP seems to be responsible for protection, the effect of CNP on autophagosome and lysosome colocalization are also hypothesized to play a significant role.

Oxidative injury is implicated in retinal damage observed in age-related macular degeneration (AMD), as well as other degenerative conditions. Abnormally elevated levels of iron accumulation within the retinal pigment epithelium have been detected in eyes with AMD, and it is suspected to play a role in the pathogenesis through the production of reactive oxygen species (ROS). Ceria nanoparticles (CNP) have the ability to scavenge ROS. This study sought to evaluate the ability of CNP to mitigate iron-induced oxidative stress and assess cell viability in the human ARPE-19 cell line in vitro. Cell viability was measured by an MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and compared between experimental groups undergoing 48-hr exposure to a ferrous iron solution with and without 24 hr CNP pre treatment. The CNP effect on ROS formation was evaluated additionally by H2DCFDA (2,7-dichlorodihydrofluorescein diacetate) fluorescent probe assay and superoxide dismutase assay. CNP demonstrated a three-fold increase in cell viability and a reduction in ROS generation. The results show a promising treatment modality for diseases causing oxidative damage in the eye.

This paper describes two patients with squamous cell carcinoma (SCC) of the periocular and periorbital skin who presented with trigeminal neuralgia. Both patients had previous cutaneous SCC of the scalp treated successfully with surgical resection but later presented with neuro-ophthalmic findings suggesting perineural invasion (PNI) of SCC. PNI of SCC in the periocular skin or orbit can lead to devastating effects if malignant cells seed into the orbit and adjacent cranial nerves as our two patients developed an orbital apex syndrome. Patients with a history of SCC of the scalp and forehead who later develop neuro-ophthalmological deficits or patients with persistent ocular symptoms should, in particular, be followed with a low threshold for cutaneous SCC or PNI of recurrent disease. SCC metastasizing into the periocular tissues and orbit by neural invasion is rare and carries a poor prognosis. The urgency for a prompt diagnosis and evaluation by a multidisciplinary team is warranted to prevent untoward outcomes of this skin cancer.

PURPOSE:This study compares the incidence of complications in eyes undergoing 25-gauge versus 20-gauge vitreoretinal procedures.METHODS:Retrospective case series. A chart review of consecutive patients who underwent primary 25-gauge (129 eyes) and 20-gauge (129 eyes) vitreoretinal surgery by four surgeons at a single center between September 2002 and November 2005 was conducted.RESULTS:Mean follow-up was 9.1 +/- 4.9 months in 25-gauge eyes and 14.3 +/- 8.4 months in 20-gauge eyes (P < 0.01). Intraoperative complications were mainly rhegmatogenous in nature and occurred at statistically similar incidence (4.7% in 25-gauge eyes, 6.9% in 20-gauge eyes). Postoperative complications that were significantly associated with surgical method included hypotony and serous choroidal effusions (7.9% in 25-gauge eyes, 1.6% in 20-gauge eyes, P = 0.02). Other postoperative complications noted included retinal tears and detachments (5.4% in 25-gauge eyes, 4.7% in 20-gauge eyes), persistent vitreous hemorrhage (5.4% in each group), and new vitreous hemorrhage (3.9% in 25-gauge eyes, 0.8% in 20-gauge eyes). Endophthalmitis was noted only in 25-gauge eyes in 2 cases (1.6%). Cataract progression occurred at similar rates in both groups (46%).CONCLUSION:25-gauge surgery is associated with a significantly greater incidence of postoperative serous choroidal effusions and hypotony. Of particular concern in 25-gauge surgery is the increased risk of associated endophthalmitis. Operative indications and case selection may be important in minimizing the tendency toward certain postoperative events.