Ophthalmology issues in schizophrenia.

Schizophrenia is a complex mental disorder associated with not only cognitive dysfunctions, such as memory and attention deficits, but also changes in basic sensory processing. Although most studies on schizophrenia have focused on disturbances in higher-order brain functions associated with the prefrontal cortex or frontal cortex, recent investigations have also reported abnormalities in low-level sensory processes, such as the visual system. At very early stages of the disease, schizophrenia patients frequently describe in detail symptoms of a disturbance in various aspects of visual perception that may lead to worse clinical symptoms and decrease in quality of life. Therefore, the aim of this review is to describe the various studies that have explored the visual issues in schizophrenia.

Intraocular pressure fluctuations in response to the water-drinking provocative test in patients using latanoprost versus unoprostone.

Impairment of outflow facility in glaucoma causes large intraocular pressure (IOP) fluctuations that have been shown to be a risk factor for disease progression. The water-drinking provocative test (WDT) has been proposed as an indirect measurement of outflow facility to compare intraocular pressure responses of glaucoma eyes to different drugs. This study was a double-masked, randomized, parallel-group clinical trial comparing the IOP fluctuations in response to the WDT in patients using latanoprost versus unoprostone. After completing a wash-out of ocular hypotensive medications, patients with primary openangle glaucoma or ocular hypertension were randomized to receive either latanoprost (N=40) or unoprostone (N=42). IOP was measured before treatment and at 8 weeks after treatment (baseline IOP for WDT), followed by the WDT. IOP fluctuations and maximum IOP after water ingestion were compared between the two groups. Analysis of covariance was used to adjust for the effects of baseline IOP and treatment efficacy. The mean percentage reduction of IOP was 27% in patients using latanoprost, as compared to 13% in patients using unoprostone (p<0.001). Patients on treatment with latanoprost had significantly less IOP fluctuations in response to the WDT, compared to patients using unoprostone. From an overall baseline IOP of 20.0 mmHg and an overall treatment efficacy of 20%, the mean+/-standard error of the mean (SEM) of the IOP fluctuation during the WDT was 5.3+/-0.4 mmHg in the unoprostone group, and 3.6+/-0.4 mmHg in the latanoprost group (p=0.005, ANCOVA). This could represent an additional benefit of latanoprost over unoprostone in controlling the intraocular pressure of glaucomatous patients.

Medical backgrounders: glaucoma.

Glaucoma is a leading cause of irreversible blindness in the world. Currently, glaucoma is diagnosed as a progressive optic neuropathy with characteristic optic disc and nerve fiber layer damage, usually associated with loss of visual function. The intraocular pressure (IOP) is the most important risk factor for the disease, although a significant proportion of patients do not have elevated IOP. Other risk factors include older age, African descent, myopia and family history of the disease. The ophthalmoscopic examination of the optic disc is essential to identify the signs of glaucomatous optic neuropathy, such as increased cupping, neuroretinal rim thinning or optic disc hemorrhages. Glaucomatous visual field loss usually starts in the periphery, and loss of central vision does not occur until late in the course of the disease. Visual function is most commonly assessed by standard automated perimetry; however, as many as 50% of nerve fibers can be lost before the appearance of visual field defects in this test. Newer technologies have been developed to find more sensitive ways to detect early glaucoma using both functional (short-wavelength automated perimetry and frequency-doubling perimetry) and structural (scanning laser topography, optical coherence tomography and scanning laser polarimetry) measurements. The management of glaucoma is based on lowering the intraocular pressure to prevent further optic nerve damage. Currently, there are five major classes of medications that are used to lower the intraocular pressure: Beta-adrenergic antagonists, adrenergic agonists, parasympathomimetics, prostaglandin-like analogues and carbonic anhydrase inhibitors. The goal of therapy is to maintain adequate vision for patients during their lifetime, keeping in mind the possible adverse effects of the drugs. If additional lowering of IOP is indicated or if medication fails to sufficiently lower the IOP, laser trabeculoplasty is usually the next step. If IOP is still not adequately controlled, incisional glaucoma surgery is indicated. Neuroprotective agents, which directly protect the optic nerve in glaucoma, are being evaluated in clinical trials.