Spontaneous microscopic hyphema secondary to iris vascular tufts: Case report with video documentation.

A 71-year-old woman presented with spontaneous microhyphema in her left eye, causing blurry vision. Bleeding stopped spontaneously shortly after several cycles of digital compression on the upper eyelid, (which were documented in video), and therefore, did not require laser photocoagulation, a possible approach previously explained to the patient. A microhemangioma at the edge of the iris was identified to be the cause of the condition. The hemorrhage did not recur during the follow-up period (9 months).

Comparison of anterior segment optical coherence tomography angiography and fluorescein angiography for iris vasculature analysis.

PURPOSE: The aim of this study is to perform imaging of irises of different colors using spectral domain anterior segment optical coherence tomography angiography (AS-OCTA) and iris fluorescein angiography (IFA) and compare their effectiveness in examining iris vasculature. METHODS: This is a cross-sectional observational clinical study. Patients with no vascular iris alterations and different pigmentation levels were recruited. Participants were imaged using OCTA adapted with an anterior segment lens and IFA with a confocal scanning laser ophthalmoscope (cSLO) adapted with an anterior segment lens. AS-OCTA and IFA images were then compared. Two blinded readers classified iris pigmentation and compared the percentage of visible vessels between OCTA and IFA images. RESULTS: Twenty eyes of 10 patients with different degrees of iris pigmentation were imaged using AS-OCTA and IFA. Significantly more visible iris vessels were observed using OCTA than using FA (W = 5.22; p < 0.001). Iris pigmentation was negatively correlated to the percentage of visible vessels in both imaging methods (OCTA, rho = - 0.73, p < 0.001; IFA, rho = - 0.77, p < 0.001). Unlike FA, AS-OCTA could not detect leakage of dye, delay, or impregnation. Nystagmus and inadequate fixation along with motion artifacts resulted in lower quality images in AS-OCTA than in IFA. CONCLUSIONS: AS-OCTA is a new imaging modality which allows analysis of iris vasculature. In both AS-OCTA and IFA, iris pigmentation caused vasculature imaging blockage, but AS-OCTA provided more detailed iris vasculature images than IFA. Additional studies including different iris pathologies are needed to determine the most optimal scanning parameters in OCTA of the anterior segment.

Efficacy and safety of intravitreal bevacizumab in eyes with neovascular glaucoma undergoing Ahmed glaucoma valve implantation: 2-year follow-up.

PURPOSE: To evaluate the efficacy and safety of intravitreal bevacizumab (IVB) in eyes with neovascular glaucoma (NVG) undergoing Ahmed glaucoma valve (AGV) implantation. METHODS: This was a multicentre, prospective, randomized clinical trial that enrolled 40 patients with uncontrolled neovascular glaucoma that had undergone panretinal photocoagulation and required glaucoma drainage device implantation. Patients were randomized to receive IVB (1.25 mg) or not during Ahmed valve implant surgery. Injections were administered intra-operatively, and 4 and 8 weeks after surgery. RESULTS: After a mean follow-up of 2.25 ± 0.67 years (range 1.5-3 years), both groups showed a significant decrease in IOP (p < 0.05). There was no difference in IOP between groups except at the 18-month interval, when IOP in IVB group was significantly lower (14.57 ± 1.72 mmHg vs. 18.37 ± 1.06 mmHg - p = 0.0002). There was no difference in survival success rates between groups. At 24 months, there was a trend to patients treated with IVB using less antiglaucoma medications than the control group (p = 0.0648). Complete regression of rubeosis iridis was significantly more frequent in the IVB group (80%) than in the control group (25%) (p = 0.0015). CONCLUSIONS: Intravitreal bevacizumab may lead to regression of new vessels both in the iris and in the anterior chamber angle in patients with neovascular glaucoma undergoing Ahmed glaucoma valve implantation. There is a trend to slightly lower IOPs and number of medications with IVB use during AGV implantation for neovascular glaucoma.

Rabbit rubeosis iridis induced by intravitreal latex-derived angiogenic fraction.

PURPOSE: To describe the presence of iris neovascularization in a rabbit-model of retinal neovascularization induced by the intravitreal injection of latex-derived angiogenic fraction microspheres (LAF). MATERIALS AND METHODS: Eight New Zealand rabbits received one intravitreal injection of PLGA (L-lactide-co-glycolide) microspheres with 50 ug of LAF in the right eye (Group A). Microspheres without the LAF (0.1 ml) were injected in controls (Group B; n = 8). Follow-up with clinical evaluation and iris fluorescein angiography was performed after 4 weeks when eyes were processed for light microscopy. RESULTS: All eyes from Group A showed significant vascular dilation, conjunctival hyperemia and neovascularization on the iris surface, after LAF injection. No vascular changes were observed in Group B. CONCLUSIONS: The intravitreal injection of microspheres containing the LAF can induce rubeosis iridis in rabbits and could be used as a simple experimental model for iris neovascularization.

Proliferation of the vascular endothelium of the iris following total debridement of the corneal epithelium and limbal excision of rabbits.

BACKGROUND: Damage to the corneal epithelium causes not only a reaction for its repair but also affects other parts of the cornea as well as different components of the anterior segment of the eye. The purpose of this investigation was to analyze the consequences, following epithelial and limbal damage, to the iris of rabbits (Oryctolagus cuniculus). METHODS: The corneal epithelium was thoroughly scraped followed by surgical excision of the limbus. Next, (3)H-thymidine ((3)H-TdR) was injected intravitreally both into the right (experimental) and left (control) eyes which had their anterior segments processed for autoradiography at intervals of 2, 7 and 21 days after surgery (three rabbits per interval). The irises were also examined with scanning-electron and confocal microscopy after Evans blue injection. RESULTS: There was a high frequency of labeling in the cells of the iris blood vessels in the experimental eye, particularly the endothelial ones. The ratio of labeled cells between experimental and control irises was 40:1, with a population of nuclei increasing by 25% and remaining labeled up to 21 days. There was also an increase in the volume of the iris vasculature as shown by confocal microscopy. The high labeling frequencies of the vascular cells were observed throughout the iris from the ciliary to the pupillary regions. CONCLUSIONS: The lesions on the corneal epithelium elicit proliferation of the iris vascular cells, mainly its endothelium, as well as an early breakdown of the blood-aqueous barrier. The daughter cells resulting from the damage to the eye surface were detected up to 21 days after a single injection of (3)H-TdR, most likely due to their slow turnover. As a consequence of this proliferation, the vasculature of the iris increased in volume.

[Pathological features of diabetic retinopathy]. / Aspectos patológicos da retinopatia diabética.

Diabetic retinopathy continues to be an important cause of adult blindness among Americans and Brazilians. There are determinant environmental factors in the development of diabetic retinopathy although increasing evidence suggests a genetic component in diabetic retinopathy. The advances made during the last two decades with the purpose of improving the understanding of the mechanisms involved in the development and progression of diabetic retinopathy have prompted this review. This article has the purpose of revising and updating concepts about the ocular physiopathology of diabetes mellitus.

Aspectos patológicos da retinopatia diabética / Pathological features of diabetic retinopathy

A retinopatia diabética continua sendo importante causa de cegueira entre adultos americanos e brasileiros. Existem fatores ambientais determinantes para o desenvolvimento da retinopatia diabética apesar de número crescente de evidências sugerirem um componente genético na retinopatia diabética. Os avanços realizados nas últimas décadas com o objetivo de melhorar o entendimento dos mecanismos envolvidos no desenvolvimento e progressão da retinopatia diabética estimularam esta revisão. Este artigo tem como objetivo revisar e atualizar conceitos acerca da fisiopatologia ocular do diabetes mellitus.

Vascular effects of acetylcholinesterase inhibitors in the rabbit eye: a study with fasciculin and physostigmine.

The vascular effects of fasciculin and physostigmine, two acetylcholinesterase inhibitors, were studied with radioactively labelled microspheres in the rabbit eye. In addition, the effects on the intraocular pressure, pupil size and the aqueous humor protein concentration were determined. Both drugs were injected intracamerally in pentobarbital anesthetized and indomethacin pretreated animals. Fasciculin injected in a dose of 0.5 micrograms (0.7 x 10(-10)M) reduced blood flow in the anterior uvea as determined 30 and 60 min after injection. Higher doses had inconsistent effects. Physostigmine injected in a dose of 3 micrograms (1.1 x 10(-8)M) also reduced blood flow in the anterior uvea. The effect was most pronounced in the iris. Neither drug had any appreciable effect on choroidal or retinal blood flow. Both drugs caused pupillary constriction but the reduction in blood flow was not secondary to miosis. The effects on the intraocular pressure and aqueous humor protein concentration were inconsistent. The reduction in blood flow of the anterior uvea after intracameral injection of acetylcholinesterase inhibitors is consistent with a cholinergic vasoconstriction previously described in the eye during electrical stimulation of the oculomotor nerve.

A prospective study of acute central retinal artery obstruction. The incidence of secondary ocular neovascularization.

We conducted a prospective study to determine the incidence of ocular neo-vascularization following acute central retinal artery obstruction. Only patients initially evaluated within 7 days of visual loss were eligible. Any patient with pre-existing ocular neovascularization or clinical evidence of the ocular ischemic syndrome noted at the initial evaluation was excluded. During the 18-month study, 33 consecutive patients were enrolled. Six patients subsequently developed neovascularization of the iris, an incidence of 18.2%. In these six patients, neovascularization of the iris appeared as early as 12 days to as late as 15 weeks following the artery obstructions. Five of the six patients (15.2% of the total) later developed neovascular glaucoma. Another patient in this series developed neovascularization of the optic disc without neovascularization of the iris, an incidence of 3.0%. Only two of the seven patients with ocular neovascularization had ipsilateral hemodynamically significant carotid artery disease as determined by noninvasive carotid artery testing. This study confirms results of previous retrospective studies that the incidence of ocular neovascularization after central retinal artery obstruction is higher than commonly thought. It also shows that, in the majority of cases, carotid artery disease is not responsible for the neovascularization seen after central retinal artery obstruction.

Combined branch retinal artery and central retinal vein obstruction.

We observed seven patients with the unusual combination of a central retinal vein obstruction in conjunction with a simultaneous branch retinal artery obstruction. The patients presented with sectoral retinal whitening, as well as diffuse peripapillary and superficial retinal hemorrhages. In five of the seven patients, the retinal hemorrhages appeared most florid in the territory of the obstructed arteriole, resulting initially in the consideration that these cases represented a combined branch retinal artery and branch retinal vein obstruction. In all cases, however, the presence of dilated, tortuous veins with diffuse retinal hemorrhages, in addition to generalized delay in arteriovenous transit on fluorescein angiography, localized the venous blockage to the central retinal vein. No intra-arterial retinal emboli were visualized. Initially, five of the seven patients suffered markedly diminished visual function; although visual acuity returned to near normal in all but two patients. In the two patients with non-resolving, markedly impaired visual acuity, neovascularization of the iris complicated the clinical course. Both of these patients were treated with panretinal photocoagulation, with resolution of the iris neovascularization. These seven patients highlight another variation of combined arterial and venous retinal vascular disease.

The efficacy of panretinal photocoagulation for neovascularization of the iris after central retinal artery obstruction.

Panretinal photocoagulation (PRP) is widely used for a variety of ischemic ocular conditions. In diseases that produce neovascularization of the iris (NVI), such as diabetes mellitus and central retinal vein obstruction, a judiciously timed PRP can reduce the incidence of neovascular glaucoma. Neovascularization of the iris can occur after central retinal artery obstruction (CRAO) as well. In this article, the authors report the outcome of 17 patients who received PRP to treat rubeosis iridis secondary to CRAO. Eleven of the 17 patients (65%) showed regression of NVI after PRP. Although the uncontrolled and retrospective nature of this study precludes drawing definitive conclusions from these data, PRP appears to be effective in reducing the incidence of neovascular glaucoma, if it is delivered before the development of elevated intraocular pressure (IOP). Once neovascular glaucoma occurs, additional modalities appear to be necessary in order to adequately control the elevated IOP.

Iris neovascularization associated with obstruction of the central retinal artery.

The authors retrospectively reviewed 168 cases of central retinal artery obstruction (CRAO) to determine the rate of occurrence of iris neovascularization (NVI) and to identify any factors that may predispose to its development. Twenty-eight well-documented cases of NVI after CRAO were detected, an occurrence rate of 16.6%. After evaluating the intravenous fluorescein angiograms of these patients, the authors conclude that an extreme prolongation of the retinal arteriovenous transit time is an independent risk factor for the subsequent development of NVI. Twelve of 18 eyes (66.6%) in the NVI group, versus seven of 29 eyes (24.1%) in the control group, showed such prolongation (P less than 0.02).