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T A Ciulla

Publications and source records attributed to T A Ciulla.

At least 19 recordsLinked to original sources
PubMed2005

Photodynamic therapy with PhotoPoint photosensitiser MV6401, indium chloride methyl pyropheophorbide, achieves selective closure of rat corneal neovascularisation and rabbit choriocapillaris.

AIM: The new photosensitiser PhotoPoint MV6401, indium chloride methyl pyropheophorbide, was assessed as a possible ocular photodynamic therapy agent in a rat model of experimentally induced corneal neovascularisation and in choriocapillaris closure in the rabbit. Optimal drug and light activation parameters were determined. METHODS: MV6401 (Miravant Pharmaceuticals, Inc, Santa Barbara, CA, USA) was activated at 664 nm using a DD3-0665 (Miravant Systems Inc) 0.5 W diode laser. Corneal neovascularisation in rats was induced using an N-heptanol technique. The evaluated drug dosages, light dosages, and post-injection activation times ranged from 0.01-0.1 micromol/kg, 5-25 J/cm(2), and 10-60 minutes, respectively. The efficacy of MV6401 on normal choriocapillaris and choroidal vessels was evaluated in rabbits with indirect ophthalmoscopy, fundus photography, fluorescein angiography, and histology. In rabbits, the evaluated drug dosages, light dosages, and post-injection activation times ranged from 0.025-0.25 micromol/kg, 3.3-20 J/cm(2), and 10 minutes, respectively. RESULTS: In the rat corneal neovascularisation model, an optimal intravenous drug dosage of 0.075 micromol/kg was activated by a 20 J/cm(2) light dose at 10 minutes after drug administration, the results of which demonstrated early evidence of efficacy in ocular neovascularisation. In rabbits, closure of the normal choriocapillaris was selectively achieved at a drug dosage of 0.15 micromol/kg using light doses from 3.3 to 20 J/cm(2). CONCLUSION: PhotoPoint MV6401 is a potent photosensitiser that demonstrates both efficacy and selectivity in experimental ocular models.

Animals↗
PubMed2003

The effects of dorzolamide on choroidal and retinal perfusion in non-exudative age related macular degeneration.

AIM: To comprehensively evaluate the effects of dorzolamide on the choroidal and retinal circulation in patients with age related macular degeneration (AMD). METHODS: In this randomised, double masked, parallel study, 36 non-exudative AMD patients were randomised in a 2 to 1 fashion to placebo versus topical dorzolamide and underwent assessment of their choroidal and retinal circulation. Scanning laser ophthalmoscope indocyanine green angiograms (ICGA) were analysed by a new area dilution analysis technique. Four areas in the perifoveal region and two areas in the temporal peripapillary region were evaluated by plotting intensity of fluorescence of each area over time. The means of the choroidal filling times and the heterogeneity of the filling times were assessed. Scanning laser ophthalmoscope fluorescein angiography (FA) was evaluated for retinal arteriovenous passage (AVP) times by plotting intensity of fluorescence of retinal vessels over time. Assessment was performed at baseline and at 4 months. RESULTS: Compared to placebo, AMD patients treated with dorzolamide showed a significantly increased rapidity of choroidal filling in the superior and inferior peripapillary regions (p=0.007, p=0.02, respectively). No significant difference in choroidal filling times was found in any of the perifoveal areas (p=0.9). Also, on FA assessment, treatment with dorzolamide showed no statistical differences in AVP times (p=0.19). CONCLUSIONS: Dorzolamide may increase peripapillary choroidal perfusion in non-exudative AMD patients. Further studies are merited.

Aged↗
PubMed2003

Choroidal neovascular membrane inhibition in a laser treated rat model with intraocular sustained release triamcinolone acetonide microimplants.

AIM: To determine if intravitreal microimplants containing triamcinolone acetonide (TAAC) inhibit experimental fibrovascular proliferation (FVP) induced by laser trauma in a rat as a model of choroidal neovascular membranes (CNVMs). METHODS: 20 anaesthetised male Brown Norway rats received a series of eight krypton red laser lesions per eye (647 nm, 0.05 s, 50 micro m, 150 mW). Three types of sterilised TAAC microimplant designs were evaluated: implant A consisting of 8.62% TAAC/20% polyvinyl alcohol (PVA) matrix (by dry weight); implant B consisting of 3.62% TAAC/20% PVA matrix; and implant C consisting of a dual 8.62% TAAC/20% PVA matrix design combined with a central core (0.5 mm) of compressed TAAC to extend the implant release time. For each animal studied, one eye received one of the three aforementioned TAAC implant designs, while the fellow eye received a control implant consisting of PVA but without TAAC. The animals were sacrificed at day 35 and ocular tissues were processed for histological analysis. Serial histological specimens were methodically assessed in a masked fashion to analyse each laser lesion for the presence or absence of FVP; maximum FVP thickness for each lesion was measured from the choriocapillaris. RESULTS: All three types of TAAC implants inhibited FVP relative to controls in a statistically significant fashion. In the eyes that received implant A (n = 8), the mean thickness of the recovered lesions (n = 36) measured 32 (SD 22) micro m, compared to 52 (30) micro m (p <0.005) for the recovered lesions (n = 40) from the fellow control eyes. In the eyes that received implant B (n = 6), the mean thickness of the recovered lesions (n = 31) measured 28 (15) micro m, compared to 50 (29) micro m (p <0.001) for the lesions (n = 19) recovered from the fellow control eyes. In the eyes that received implant C (n = 6), the mean thickness of the recovered lesions (n = 21) measured 39 (24) micro m, compared to 65 (30) micro m (p <0.001) for the lesions (n = 39) recovered from the fellow control eyes. CONCLUSIONS: All three of the tested TAAC microimplant designs produced potent inhibition of FVP in a rat model of CNVMs. There were no differences in inhibition of FVP between the three different types of implants evaluated. This study provides evidence that: (1) corroborates previous investigations that propose TAAC as a potential treatment for CNVMs in humans, and (2) demonstrates TAAC can be effectively delivered via long acting sustained release intraocular microimplants. It should be noted, however, that the FVP observed in this rat laser trauma may not reflect the CNVM observed in human with exudative age related macular degeneration (AMD).

Animals↗
PubMed2002

Intravitreal triamcinolone in subfoveal recurrence of choroidal neovascularisation after laser treatment in macular degeneration.

BACKGROUND: Laser treatment of extrafoveal well delineated choroidal neovascularisation in exudative age related macular degeneration has a high rate of failure with subsequent severe vision loss from subfoveal involvement. Laser treatment may limit scotoma size, but is unpalatable because of early persistent vision loss. Intravitreal triamacinolone injection may be an acceptable alternative therapy in such disparate cases. METHODS: 14 consecutive patients with recurrent neovascularisation were treated with a single 4.0 mg injection of triamacinolone and followed for up to 1 year. Visual results were compared with published data from the Macular Photocoagulation Study of recurrent neovascularisation. RESULTS: Mean visual acuity remained stable at about 20/200 throughout the study period in the treated patients. This is comparable to the outcomes in the Macular Photocoagulation Study for laser retreated patients, and better than the observation group. CONCLUSIONS: Intravitreal triamcinolone may be an acceptable treatment of subfoveal recurrent neovascularisation while avoiding early persistent vision loss from laser retreatment.

Anti-Inflammatory Agents↗
PubMed2001

Intravitreal triamcinolone acetonide inhibits choroidal neovascularization in a laser-treated rat model.

OBJECTIVE: To determine if intravitreal triamcinolone acetonide (TAAC) inhibits experimental choroidal neovascular membranes induced by laser trauma in a rat model. METHODS: Nineteen anesthetized male Brown Norway rats received a series of 8 krypton red laser lesions per eye (647 nm, 0.05 seconds, 50 microm, and 150 mW in 17 rats, and 200 mW in 2 rats). One eye received an intravitreal injection of triamcinolone acetonide (20 microL, 0.8 mg) and the other eye received an injection of isotonic sodium chloride solution. Fundus and fluorescein angiography examinations occurred just before euthanasia and tissue processing for histopathology on day(s) 0, 1, 3, 7, 14, 21, 28, and 35. RESULTS: From the control eyes that underwent photocoagulation at 150 mW, 57 discrete lesions with definitive fibrovascular proliferations were observed at 21, 28, and 35 days, arising from a total of 72 spots placed (79% yield). From the control eyes that underwent photocoagulation at 200 mW, 11 discrete lesions with definitive fibrovascular proliferations were observed at 28 days, arising from a total of 16 spots placed (69% yield). In the TAAC-treated group, no fibrovascular proliferations were observed in the 72 lesions and in the 16 lesions created with 150 mW and 200 mW, respectively. CONCLUSION: Intravitreal TAAC is a potent inhibitor of fibrovascular proliferations in a rat model of choroidal neovascular membranes induced by laser trauma. CLINICAL RELEVANCE: This study corroborates previous investigations that propose TAAC as a potential treatment for choroidal neovascular membranes in humans.

Animals↗
PubMed2001

Macular pigment optical density in a midwestern sample.

OBJECTIVE: To assess the distribution of the macular pigments (MPs) lutein (L) and zeaxanthin (Z) in a healthy sample more representative of the general population than past studies and to determine which dietary factors and personal characteristics might explain the large interindividual differences in the density of these MPs. DESIGN: Prevalence study in a self-selected population. PARTICIPANTS: Two hundred eighty healthy adult volunteers, consisting of 138 men and 142 women, between the ages of 18 and 50 years, recruited from the general population. METHODS: MP optical density was measured psychophysically at 460 nm by use of a 1 degrees test field. Serum was analyzed for carotenoid and vitamin E content with reversed-phase high-performance liquid chromatography. Usual intakes of nutrients over the past year were determined by means of a food frequency questionnaire. MAIN OUTCOME MEASURES: MP optical density. RESULTS: Mean MP optical density measured 0.211 +/- 0.13, which is approximately 40% lower than the average reported in smaller, less representative studies. MP density was 44% lower in the bottom versus the top quintile of serum L and Z concentrations. Similarly, MP density was 33% lower in the bottom compared with the top quintile of L and Z intake. MP density was 19% lower in blue-grey-eyed subjects than in subjects with brown-black irises. When all variables were considered together in a general linear model of determinants of MP, statistically significant (P < 0.05) relationships were found between MP density and serum L and Z, dietary L and Z intake, fiber intake, and iris color. CONCLUSIONS: These data suggest that MP values in this healthy adult population are lower than in smaller select samples. Moreover, these data indicate that MP is related to serum L and Z, dietary L and Z intake, fiber intake, and iris color.

Adolescent↗
PubMed2001

Delayed suprachoroidal hemorrhage after glaucoma filtration procedures.

OBJECTIVES: To determine the incidence of, risk factors for, and outcomes of delayed suprachoroidal hemorrhage (DSCH) after glaucoma filtration surgery. DESIGN: Retrospective case-control study. PARTICIPANTS: All patients undergoing glaucoma filtration procedures between 1986 and 2000 at Indiana University who were diagnosed postoperatively with suprachoroidal hemorrhage. A total of 66 patients with DSCH were identified. These were compared with a randomly selected group of patients who underwent similar procedures but did not have suprachoroidal hemorrhage. METHODS: Total cases of DSCH were initially compared with the total number of glaucoma surgeries to determine the overall incidence and the incidence in the different procedures. Subsequently, a case-control study was performed comparing the group with hemorrhage to the control group to identify risk factors. Finally, outcomes and prognostic factors were determined by comparing vision preoperatively and postoperatively and parameters of patients with good and poor outcomes. MAIN OUTCOME MEASURES: Incidence of DSCH, risk factors associated with its occurrence, visual outcomes, and factors important for prognosis. RESULTS: Of a total of 2285 glaucoma filtration procedures, 66 (2.9%) cases of DSCH were identified. It developed in 9 of 615 (1.5%) trabeculectomies without antimetabolite, 30 of 1248 (2.4%) trabeculectomies with antimetabolite, 2 of 72 (2.8%) valved tube shunt implantations, and 25 of 350 (7.1%) nonvalved tube shunt implantations. The increased incidence of DSCH after tube shunts compared with trabeculectomy-associated DSCH was significant (P < 0.0001) with an odds ratio of 3.2. The risk factors for DSCH after glaucoma surgery include white race (P = 0.012), anticoagulation (P = 0.034), severe postoperative hypotony (P = 0.033), and aphakia/anterior chamber intraocular lens (P = 0.002). The visual outcomes of patients with hemorrhage were poor, with a decrease in logarithm of the minimum angle of resolution visual acuity from 0.72 to 1.36, which was statistically significant compared with the controls (P < 0.009). CONCLUSIONS: Delayed suprachoroidal hemorrhage occurs more frequently after tube shunt implantation than after trabeculectomy. Caution should be exercised when operating on patients with known risk factors, because the visual outcomes after DSCH are poor.

Aged↗
PubMed2001

Ocular perfusion and age-related macular degeneration.

PURPOSE: To review the role of ocular perfusion in the pathophysiology of age-related macular degeneration (AMD), the leading cause of irreversible blindness in the industrialized world. METHODS: Medline search of the literature published in English or with English abstracts from 1966 to 2000 was performed using various combinations of relevant key words. RESULTS: Vascular defects have been identified in both nonexudative and exudative AMD patients using fluorescein angiographic methods, laser Doppler flowmetry, indocyanine green angiography, and color Doppler imaging. CONCLUSION: Although these studies lend some support to the vascular pathogenesis of AMD, it is not possible to determine if the choroidal perfusion abnormalities play a causative role in nonexudative AMD, if they are simply an association with another primary alteration, such as a primary RPE defect or a genetic defect at the photoreceptor level, or if they are more strongly associated with one particular form of this heterogeneous disease. Further study is warranted.

Blood Flow Velocity↗
PubMed2001

Relation between dietary intake, serum concentrations, and retinal concentrations of lutein and zeaxanthin in adults in a Midwest population.

BACKGROUND: Information on concentrations of retinal carotenoids (macular pigment, or MP) is of particular interest because MP protects against age-related macular degeneration, the leading cause of irreversible blindness in the United States. OBJECTIVE: This study was designed to evaluate the relation between dietary intake, blood concentrations, and retinal concentrations of carotenoids in a large group of volunteers. DESIGN: Two hundred eighty volunteers in the Indianapolis area completed health and diet questionnaires, donated a blood sample, and participated in MP density assessment to determine retinal carotenoid status. Dietary intake was assessed by food-frequency questionnaire. Serum concentrations of lutein, zeaxanthin, and beta-carotene were measured by HPLC. MP optical density (MPOD) was determined psychophysically with a 460-nm, 1 degrees test stimulus. RESULTS: Average MPOD was 0.21 +/- 0.13. Average intakes of lutein + zeaxanthin and beta-carotene were 1101 +/- 838 and 2935 +/- 2698 microg/d, respectively. Although several key dietary intake variables (eg, lutein + zeaxanthin and beta-carotene) differed by sex, no significant sex differences were found in either serum concentrations of lutein and zeaxanthin or MPOD. Serum beta-carotene concentrations were significantly higher in women than in men. Serum lutein + zeaxanthin and dietary intake of lutein + zeaxanthin were significantly correlated and significantly related to variations in MPOD (r = 0.21, P < 0.001, and r = 0.25, P < 0.001, respectively). CONCLUSIONS: Retinal carotenoids can be measured in epidemiologic studies. In this study, MPOD was associated with lutein + zeaxanthin in the diet and the serum. Retinal concentrations, however, were influenced by other factors as well. To understand the effect of dietary lutein + zeaxanthin intake on the retina and risk of age-related eye disease, future studies should include measures of macular concentrations of these pigments.

Adult↗
PubMed2001

Presumed ocular histoplasmosis syndrome: update on epidemiology, pathogenesis, and photodynamic, antiangiogenic, and surgical therapies.

Presumed ocular histoplasmosis involves the classic triad of discrete atrophic choroidal scars in the macula or midperiphery known as histo spots, peripapillary atrophy, and choroidal neovascularization, which leads to severe loss of central vision. The histo spots from which the choroidal neovascularization develop do not show active inflammation but do represent focal defects in Bruch membrane that could facilitate development of choroidal neovascularization. The macular photocoagulation studies unequivocally show the benefit of photocoagulation compared with observation in reducing the risk of vision loss in patients with presumed ocular histoplasmosis, well defined extrafoveal or juxtafoveal choroidal neovascularization, and choroidal neovascularization in the peripapillary area. However, laser treatment itself causes an absolute scotoma correlating with the site of the laser photocoagulation scar, and subfoveal choroidal neovascularization is not amenable to laser photocoagulation because this would cause a blinding central scotoma. Consequently, other treatments have been sought. The Verteporfin in Ocular Histoplasmosis study evaluated photodynamic therapy for subfoveal choroidal neovascularization caused by presumed ocular histoplasmosis and demonstrated stabilization of the choroidal neovascularization and visual acuity benefit. In addition to photodynamic therapy, antiangiogenic compounds are being developed for choroidal neovascularization caused by age-related macular degeneration, and these agents will likely be of benefit in presumed ocular histoplasmosis associated choroidal neovascularization. Finally, submacular surgery for the removal of subfoveal choroidal neovascularization has promising results. The results of these research efforts will produce more effective therapeutic approaches in the future.

Angiogenesis Inhibitors↗
PubMed2001

Potential therapeutic application of antisense oligonucleotides in the treatment of ocular diseases.

Antisense oligonucleotides are a class of compounds being developed as therapeutic agents for many types of diseases. Although still relatively early in the clinical characterisation, the power of this technology lies in the ability to utilise genetic information and the known molecular mechanisms of disease to foster efficient and rational drug design. Consideration of novel approaches to treating ocular diseases is of interest because there are many ocular diseases with no satisfactory treatments. The recent availability of animal models of many ocular diseases provides the opportunity to use antisense oligonucleotides to understand the mechanisms of disease pathology and to potentially intervene therapeutically in ocular disease. There are already a number of examples where antisense oligonucleotides have been applied to the study of ocular physiology and disease and there is an antisense oligonucleotide approved for the treatment of cytomegalovirus (CMV) retinitis. We summarise current research in this area and highlight the properties of these compounds that are favourable for use as ocular therapeutics.

Animals↗
PubMed2001

Anti-angiogenic therapy of proliferative diabetic retinopathy.

Proliferative diabetic retinopathy (PDR) remains one of the major causes of acquired blindness in developed nations. This is true despite the development of laser treatment, which can prevent blindness in the majority of those who develop this complication. The hallmark of PDR is neovascularisation (NV), abnormal angiogenesis that may ultimately cause severe vitreous cavity bleeding and/or retinal detachment. Pharmacologic therapy aimed at preventing NV, as an adjunct to laser treatment, or as an alternative to laser treatment, would be a welcome addition to the armamentarium. PDR could be prevented by improved metabolic control or by pharmacologically blunting the biochemical consequences of hyperglycaemia (e.g., with aldose reductase inhibitors, inhibitors of non-enzymatic glycation or by protein kinase C (PKC) inhibition). The angiogenesis in PDR could be treated via growth factor (e.g., vascular endothelial growth factor (VEGF), insulin like growth factor-1) blockade, integrin (e.g., alpha-v beta-3) blockade or extracellular matrix alteration (e.g., with steroid compounds), or interference with intracellular signal transduction pathways (e.g., PKC and mitogen activated protein kinase pathway proteins). Numerous potentially useful anti-angiogenic compounds are in development, but two drugs are presently in clinical trials for the treatment of the preproliferative stage of PDR.

Aldehyde Reductase↗
PubMed2001

Macular pigment optical density before and after cataract extraction.

PURPOSE: Psychophysical methods of measuring macular pigment (MP) use comparisons of short- and midwave light in the fovea and parafovea to derive optical density estimates. This light must pass through the crystalline lens before absorption by the MPs can occur. The effect of lens absorption on these measures has not been adequately determined. The present study assesses the influence of lens absorption on MP measurements by comparing MP optical density (MPOD) measured before and after cataract extraction. METHODS: MPOD was measured using flicker photometry in free view at 458 nm with a 1 degrees stimulus. Twenty-nine eyes from 24 patients with cataracts sufficiently severe to require cataract extraction were evaluated. RESULTS: In the entire group of 24 patients, the mean (+/-SD) age measured 68.7 +/- 9.5 years, and the mean MPOD measured 0.19 +/- 0.11. For all 29 eyes measured, MPOD averaged 0.206 +/- 0.13 before and 0.18 +/- 0.12 after cataract extraction. MPOD measurements at the two time points (mean 8.1 +/- 4.7 weeks after surgery) were highly correlated (r = +0.58), suggesting that a cataractous lens does not influence the MP measurement technique. CONCLUSIONS: Psychophysical techniques can be used to obtain reliable measurements of MP in elderly subjects, even in those with cataracts. Moreover, differences in retinal illuminance due to varying opaqueness of the crystalline lens do not seem to have a measurable influence on MPOD.

Aged↗
PubMed2001

Transpupillary thermotherapy for subfoveal occult choroidal neovascularization: effect on ocular perfusion.

PURPOSE: To perform a descriptive analysis of the effects on ocular blood flow of transpupillary thermotherapy (TTT) for occult subfoveal choroidal neovascular membranes (CNVMs) in age-related macular degeneration (AMD). METHODS: Eleven subjects with occult subfoveal CNVM due to AMD were assessed in a masked fashion by color Doppler imaging (CDI) within 24 hours before, 24 hours after, and 1 month after undergoing TTT. RESULTS: In the posterior ciliary arteries (PCAs), there were no statistically significant changes observed in the peak systolic velocity (PSV), end diastolic velocity (EDV), or resistive index (RI) at 24 hours. At 1 month, the mean EDV decreased 36% (P = 0.0105) and the mean RI increased 3.8% (P = 0.0305) in the nasal PCA. Although there was a similar trend in the temporal PCA, the differences did not reach statistical significance. In the central retinal artery (CRA), the mean PSV decreased 16% (P = 0.0137), and the mean EDV decreased 21% (P = 0.0222) at 24 hours after treatment. There were no statistically significant differences in the CRA blood flow indices at 1 month after treatment. In the ophthalmic artery, there were no statistically significant differences observed in the mean PSV, EDV, or RI at 24 hours or 1 month after treatment. CONCLUSIONS: TTT is associated with transiently decreased volumetric blood flow in the retinal circulation 24 hours after treatment. In the posterior ciliary arteries that supply the choroid, there were no changes observed at 24 hours, but at 1 month, there was a decrease in the mean EDV and an increase in the RI in the nasal and temporal PCAs, reaching statistical significance in the nasal PCA only. This study suggests that TTT could lead to alterations in choroidal blood flow, as assessed by CDI. Further study is warranted.

Aged↗
PubMed2000

Aging affects the retrobulbar circulation differently in women and men.

BACKGROUND: While aging clearly has protean biological effects on every organ system, the differential effects of aging in women and men in the retrobulbar vasculature, to our knowledge, have never been investigated. Because glaucoma and age-related macular degeneration are closely linked to advanced age, we performed a cross-sectional study using color Doppler imaging of 4 retrobulbar vessels in both healthy women and men. OBJECTIVE: To define the influence of aging per se on ocular hemodynamics. METHODS: Women (n = 73) and men (n = 55), aged from 20 to 90 years, free of ocular and systemic disease, and with normal intraocular pressure, were recruited for this study. Postmenopausal women who were not receiving estrogen replacement therapy were also recruited. Studies involved color Doppler imaging analysis of the ophthalmic, central retinal, and nasal and temporal posterior ciliary arteries. Ophthalmic arterial peak systolic and end-diastolic velocities and a Pourcelot resistance index were determined for each vessel. RESULTS: In both sexes, ophthalmic arterial end-diastolic velocity decreased and the Pourcelot resistance index rose with advancing age (each P<. 001); peak systolic velocity in the ophthalmic vessel was age-independent. In contrast, central retinal arterial flow velocities were unaffected by age in both sexes. In the posterior ciliary arteries, in men, flow velocities and the Pourcelot resistance index were independent of age. However, in women, end-diastolic velocity decreased with age in both the nasal and temporal posterior ciliary vessel (each P<.05); peak systolic velocity was constant; the Pourcelot resistance index in each ciliary artery rose with advancing age (each P<.05). CONCLUSION: In healthy women and men, aging-induced changes in retrobulbar hemodynamics are comparable to alterations seen in patients with glaucoma or age-related macular degeneration, suggesting that vascular changes with senescence may contribute to increased risk for these diseases in older age. Arch Ophthalmol. 2000;118:1076-1080

Adult↗
PubMed2000

Endothelin-1-mediated retinal artery vasospasm and the rabbit electroretinogram.

Electroretinogram (ERG) changes invariably accompany the selective interruption of the retinal circulation that occurs in human central retinal artery occlusion. Since arteriolar ligation or ocular hypertension in the rabbit eye is occasionally used to model human central retinal artery occlusion, we conducted the present study to determine whether selective interruption of the retinal circulation of the rabbit eye alters retinal function as measured by the ERG. The vasoconstrictor, endothelin-1, was injected into the vitreous of rabbits' eyes to induce complete vasospasm and selective interruption of the retinal circulation. This procedure was compared to vascular ligation of the ophthalmic and ciliary arteries in which both the retinal and choroidal circulations were interrupted. A total of 8 rabbits was studied. Circulation was monitored angiographically in half of the eyes, and retinal function was monitored by the ERG in the remaining eyes. Endothelin-1 obliterated retinal arteriolar blood flow without affecting choroidal blood flow for at least 1 hr. Although ERG a-wave amplitude showed a small decline over 2 hr, b-wave and oscillatory potential amplitudes (measures of inner retinal function) showed no loss over this period. In contrast, ligation of the ophthalmic and ciliary arteries produced complete obliteration of both retinal arteriolar and choroidal blood flow and complete loss of the ERG after 2 min. Endothelin-1 induces acute, selective interruption of retinal arteriolar blood flow which has no significant physiologic effect on inner retinal function of the rabbit as monitored by the ERG. The avascular rabbit retina appears to be a poor choice for modeling human retinal artery occlusion.

Animals↗