Analyzing the demographics of patients with uveitis in an indigent, urban population.

PURPOSE: To study the types of uveitis examined in a hospital serving indigent populations in need of low-cost care. METHODS: A retrospective chart review examined the electronic medical records of all patients with uveitis-related at Drexel Eye Physicians. Data collected included demographics, anatomic location of the uveitis, systemic disease associations, treatment modalities and insurance. Statistical analysis was performed using χ² or Fischer exact tests. RESULTS: 270 patients (366 eyes) were included for analysis, 67% of patients identified as African American. Most eyes (95.3%, N = 349) were treated with topical corticosteroid drops, and only 6 (1.6%) received an intravitreal implant. Immunosuppressive medications were started in 24 patients (8.9%). Nearly 80% depended to some extent on Medicare or Medicaid Assistance for treatment coverage. There was no association between insurance type and use of biologics or difluprednate. CONCLUSION: We found no association between insurance type and the prescription of medications for uveitis that should be used at home. There was a minimal number of patients prescribed medications for implantation in the office. The adherence of use of medications at home should be investigated.

GABA blockade unmasks an OFF response in ON direction selective ganglion cells in the mammalian retina.

One unique subtype of retinal ganglion cell is the direction selective (DS) cell, which responds vigorously to stimulus movement in a preferred direction, but weakly to movement in the opposite or null direction. Here we show that the application of the GABA receptor blocker picrotoxin unmasks a robust excitatory OFF response in ON DS ganglion cells. Similar to the characteristic ON response of ON DS cells, the masked OFF response is also direction selective, but its preferred direction is opposite to that of the ON component. Given that the OFF response is unmasked with picrotoxin, its direction selectivity cannot be generated by a GABAergic mechanism. Alternatively, we find that the direction selectivity of the OFF response is blocked by cholinergic drugs, suggesting that acetylcholine release from presynaptic starburst amacrine cells is crucial for its generation. Finally, we find that the OFF response is abolished by application of a gap junction blocker, suggesting that it arises from electrical synapses between ON DS and polyaxonal amacrine cells. Our results suggest a novel role for gap junctions in mixing excitatory ON and OFF signals at the ganglion cell level. We propose that OFF inputs to ON DS cells are normally masked by a GABAergic inhibition, but are unmasked under certain stimulus conditions to mediate optokinetic signals in the brain.

Light-induced changes in spike synchronization between coupled ON direction selective ganglion cells in the mammalian retina.

Although electrical coupling via gap junctions is prevalent among ganglion cells in the vertebrate retina, there have been few direct studies of their influence on the light-evoked signaling of these cells. Here, we describe the pattern and function of coupling between the ON direction selective (DS) ganglion cells, a unique subtype whose signals are transmitted to the accessory optic system (AOS) where they initiate the optokinetic response. ON DS cells are coupled indirectly via gap junctions made with a subtype of polyaxonal amacrine cell. This coupling underlies synchronization of the spontaneous and light-evoked spike activity of neighboring ON DS cells. However, we find that ON DS cell pairs show robust synchrony for all directions of stimulus movement, except for the null direction. Null stimulus movement evokes a GABAergic inhibition that temporally shifts firing of ON DS cell neighbors, resulting in a desynchronization of spike activity. Thus, detection of null stimulus movement appears key to the direction selectivity of ON DS cells, evoking both an attenuation of spike frequency and a desynchronization of neighbors. We posit that active desynchronization reduces summation of synaptic potentials at target AOS cells and thus provides a secondary mechanism by which ON DS cell ensembles can signal direction of stimulus motion to the brain.

An outbreak of fungal endophthalmitis after intravitreal injection of compounded combined bevacizumab and triamcinolone.

IMPORTANCE: Our experience may be useful to other practitioners using compounded intravitreal agents, those suspecting infectious outbreaks, and those managing fungal endophthalmitis. OBJECTIVE: To describe a series of patients with fungal endophthalmitis following intravitreal injection of combined bevacizumab and triamcinolone acetonide prepared by the same compounding pharmacy. DESIGN AND SETTING: Noncomparative case series. PARTICIPANTS: Eight eyes of 8 patients who received an intravitreal injection of compounded combined bevacizumab-triamcinolone in a period of 3 weeks had subtle, nonspecific findings that were later diagnosed as fungal endophthalmitis. MAIN OUTCOME MEASURES: Visual acuity, response to antimicrobial therapy, and number of vitreoretinal surgical operations after diagnosis of fungal endophthalmitis. RESULTS: Eight patients developed endophthalmitis 41 to 97 days after receiving the intravitreal injection, which was prepared by the same compounding pharmacy. The injections occurred at the same location in New York. Treatment was based on clinical examination findings and knowledge of the etiology of the endophthalmitis. Eventually, all patients were treated with oral voriconazole. Five of 8 patients were initially treated with intravitreal antimicrobial agents. After 3 months of follow-up, visual acuities ranged from 20/50 to hand motions. Local, state, and federal health department officials were involved in investigating the source of the outbreak. CONCLUSIONS AND RELEVANCE: In the current study, we report a fungal endophthalmitis outbreak after intravitreal injection of contaminated, compounded combined bevacizumab-triamcinolone. In this series, Bipolaris hawaiiensis was the identified causative agent. The challenge of medical diagnosis, identification of the source of the outbreak, and management experience are highlighted in our series. Our experience may be useful to other practitioners using compounded intravitreal agents, those suspecting infectious outbreaks, and those managing fungal endophthalmitis.

Rectus muscle flap tear as an independent cause of restricted motility.

Most published cases of rectus muscle flap tear have been associated with orbital trauma of various degrees of severity. When they accompany an orbital fracture, however, it is difficult to determine whether the flap tear is merely an incidental additional finding or a major contributing cause of the resulting restriction. How to treat the flap itself remains an open question. We report a 24-year-old man with an inferior rectus muscle flap tear caused by direct laceration of the muscle. The major finding was a "reverse leash" vertical restriction. Discarding the flap instead of reattaching it did not prevent a successful result. Our case supports the proposition that rectus muscle flap tear can be a restriction-producing entity.