Evidence is accumulating that pericyte-containing microvessels, which constitute the largest component of the circulatory system, actively regulate capillary perfusion. Because the retinal vasculature is highly specialized for the local control of blood flow, experimental study of its microvessels is proving useful in the quest to elucidate the mechanisms by which local perfusion is regulated. The microcirculation of the retina is also a focus of considerable attention due to its vulnerability to diabetes, which is a leading cause of vision loss. Based on the premise that the transmembrane movement of ions plays a critical role in regulating the function of pericytes, investigators are using the patch-clamp technique to study these contractile mural cells. This review highlights recent progress made in understanding how ion channels and transporters mediate responses of the retinal microvasculature to vasoactive signals.

Pars plana vitrectomy in treatment of ocular toxocariasis complications--case report.Klin Oczna. 2001;103(4-6):225-7

Ocular toxocariasis in adults may cause serious diagnostic and therapeutic problems. We describe a case of a 54-year-old farmer who developed peripheral granuloma with dense connective tissue strands joined to the disc. The diagnosis was confirmed by high ELISA titers in the serum and vitreous body. We performed pars plana vitrectomy with epiretinal membrane removal and laser photocoagulation of the inferior retina, obtaining improvement of visual acuity. After a few weeks the patient returned with central retinal detachment and macular hole. After the second vitrectomy with use of silicon oil we obtained reattachment of the retina but without functional improvement.

Toxocara canis.J Am Optom Assoc. 1979 Apr;50(4):450-4.

Toxocara canis, commonly known as the dog ascrid, is a frequent parasite of the domestic dog. If the eggs of an adult worm are accidentally ingested by a human host, usually a child, a larval form of the worm develops that can survive for a limited period in various human tissues. The retina is one of these tissues and upon the death of this organism a granulomatous reaction occurs and a fibrotic mass is formed in the retina. This unusual ophthalmoscopic appearance is demonstrated by the presentation of three fundus photographs of patients with suspected Toxocara lesions. A knowledge of this parasite and its life cycle will aid in its recognition, treatment, and possible prevention.

Cytomegalovirus retinitis associated with Acquired immunodeficiency syndrome.Zhonghua Yan Ke Za Zhi. 2005 Sep;41(9):803-6.

OBJECTIVE: To investigate the fundus characteristics, systemic features and therapeutic outcomes of cytomegalovirus (CMV) retinitis associated with acquired immunodeficiency syndrome (AIDS). METHODS: Fundus features, visual acuity, fundus fluorescence angiography (FFA) and CD4(+)T-lymphocyte counts of 15 eyes (8 patients) of CMV retinitis associated with AIDS were analyzed. The time of average follow-up was 16 months. Intravitreal injection of ganciclovir (400 microg) was performed in 4 eyes (2 patients). RESULTS: In the initial examination, visual acuity of the patients was as following: < or = 0.2, 10 eyes (66.7%); no light perception (NLP) (2 eyes); light perception (LP) (2 eyes); 0.04-0.2, 6 eyes; > or = 1.0, 3 eyes (20.0%) and 0.8 or 0.9 each for 1 eye (13.3%). The fundus manifestation includes: the retinal vasculitis; dense, full-thickness, yellow-white lesions along vascular distribution, and hemorrhage on the retinal surface; granular with irregular border featured as "cheese and ketchup retinitis" was revealed in 12 eyes; the vitreous was clear or light opaque. Late stage of the retinopathy was demonstrated in 2 eyes characterized as grayish atrophic retina, vessel-sclerotic and attenuated, retinal pigment epithelium (RPE) atrophy, prominent choroid vasculature, and optic nerve atrophy. Retinal detachment was found in 1 eye. CD4(+)T-lymphocytes counts in peripheral blood were between 0 approximately 36/mm(3), average (15.0 +/- 12.9) mm(3). Visual acuity improved, fundus lesions disappeared observably and hemorrhage was absorbed in the 4 eyes after intravitreal injection of ganciclovir. CONCLUSIONS: CMV retinitis is the severest and the most common intraocular complication in patients with AIDS. For the patients with yellow-white retinal lesions, hemorrhage and retinal vasculitis of undefined cause, the antibody of serum anti-human immunodeficiency virus (HIV) should be screened. Routing eye examination should be performed if the serological test of HIV is positive.

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