Superior Arcade Research Articles

Cryotherapy of infective foci in metastatic endophthalmitis

A man in his 20s presented with complaints of diminution of vision in both eyes for the past 15 days. He had a history of carcinoma colon for which he underwent hemicolectomy 2 months ago. There was vitritis with white fluffy exudate lesion suggestive of infective foci along the superior arcade, which was noted on fundus examination. A provisional diagnosis of endogenous endophthalmitis was made in both eyes, and pars plana vitrectomy with cryotherapy of infective foci was done. The vision of patient improved at 1-week follow-up. However, it dropped at 1 month due to macular pucker formation at the site of cryotherapy. Cryotherapy should be used with caution in lesions away from the posterior pole and in recalcitrant, nonresolving lesions.

Posterior sub-tenon injection of triamcinolone in non-resolving vitreoretinitis - A case report

Purpose: To evaluate the efficacy of posterior sub-tenon injection of triamcinolone in non-resolving vitreoretinits. Introduction: Vitreoretinits is the inflammation of the vitreous and retina. In a non-resolving case of vitreoretinitis steroids are the mainstay of treatment. Steroids can be administered via various routes into the eye. Posterior subtenon injection of Triamcinolone acetonide is an effective treatment option for anatomical and functional improvement in intermediate and posterior uveitis. Methods: A 46-year-old female presented to the outpatient department with decreased vision in her left eye for 3 months. On examination, she had a BCVA of 6/60 in her left eye. Fundoscopy showed vitreous haze grade 3 due to vitritis, multiple vitreoretinal tractional bands extending along both the superior and inferior arcade, macular edema, and a retinitis patch of less than half disc diameter size just above the superior arcade. The patient was positive for IgG antibodies to Cytomegalovirus and Herpes Simplex virus. The patient was started on oral prednisolone 1mg/kgbw once a day and topical prednisolone acetate 1.0%, nepafenac 0.3%, and timolol 0.5%. The patient was given posterior subtenon injection of 0.5ml of triamcinolone acetonide 40mg/ml. Results: She had 6/12 BCVA at the end of 1 month with resolving vitritis and macular edema. By the end of 3 months, she had fully resolved vitreoretinitis with 6/6 vision. Discussion: Most steroids used in ophthalmology are glucocorticoids, which have anti-inflammatory and immunosuppressive activity. Triamcinolone Acetonide is a minimally water-soluble suspension. Triamcinolone crystals slowly dissolve into the vitreous. This creates a diffusional gradient from the vitreous to the macula with minimal systemic exposure. Our study also showed significant improvement in visual acuity and reduction in macular edema with a single posterior subtenon injection of triamcinolone acetonide. Conclusion: A subtenon injection of triamcinolone acetonide appears to be an effective treatment for decreased vision associated with intermediate and posterior uveitis without any significant side effects.

ASSESSMENT OF QUALITY AND ADEQUACY OF PANRETINAL PHOTOCOAGULATION IN PROLIFERATIVE DIABETIC RETINOPATHY USING ULTRA-WIDEFIELD IMAGING.

To assess the characteristics of completed panretinal photocoagulation (PRP), using ultra-widefield imaging in proliferative diabetic retinopathy. Quantitative assessment of ultra-widefield imaging images of 133 patients with proliferative diabetic retinopathy with completed PRP was made using ImageJ software. The parameters assessed included distance of laser spots from the optic disk, foveal center, superior and inferior arcades, and extent of the maximum width of laser. Areas assessed were total area of the image, area of the inner limit within which laser spots are restricted, minimum areas of unlasered patches, total area lasered, and ideal area to be covered by PRP. Two hundred one images were assessed for the final analysis. The mean distance of laser spots was 4.2 ± 2.4 mm from the optic disk (nasal) and 6.6 ± 2.5 mm from the foveal center (temporal). The mean distance of laser spots from the superior arcade vessel was 3.2 ± 1.9 mm and 6.2 ± 4.4 mm from the inferior arcade. The mean area of the retina that should have been ideally lasered was found to be 900 ± 267 mm 2 , and the actual area lasered was found to be 681 ± 254.4 mm 2 . Approximately one-quarter area of the retina continues to remain ischemic because of the lack of inadequate coverage of PRP. Further longitudinal studies are recommended, using ultra-widefield imaging to objectively assess the adequacy of PRP and its role in modulating the course of progression of the retinopathy.

A 48-year-old Caucasian man with unilateral "smudge" in inferior visual field.

To report an increasingly prevalent fundoscopic manifestation of syphilitic uveitis. Case report of a patient with acute retinal necrosis secondary to syphilis. A 48-year-old man presented with decreased vision, anterior segment inflammation, and a wedge-shaped retinal lesion in the superior periphery, with a diaphanous leading edge extending down towards the superior arcade. The patient was HIV+ and poorly compliant with therapy. The top three differential diagnoses were herpetic necrotizing retinitis, syphilis, and lymphoma. An extensive lab workup was positive for syphilis. The patient was treated with IV penicillin G and demonstrated improvement in visual acuity and exam. There have been an increasing number of reports of syphilis patients, especially in the population of men who have sex with men, who present with fundus findings similar to acute retinal necrosis. These findings include a characteristic ground glass, translucent appearance of unifocal or multifocal lesions, primarily affecting the inner retina and sometimes associated with co-localizing occlusive vasculitis. Treatment with IV penicillin G is warranted and has demonstrated good visual recovery.

Deep branch of the radial nerve: effect of pronation/supination on longitudinal nerve alignment

ObjectiveTo evaluate the effect of maximal pronation and supination of the forearm on the alignment and anatomic relationship of the deep branch of the radial nerve (DBRN) at the superior arcade of the supinator muscle (SASM) by using high-resolution ultrasound (HRUS).Materials and methodsIn this cross-sectional study, HRUS in the long axis of the DBRN was performed in asymptomatic participants enrolled from March to August 2021. DBRN alignment was evaluated by measuring angles of the nerve in maximal pronation and maximal supination of the forearm independently by two musculoskeletal radiologists. Forearm range of motion and biometric measurements were recorded. Student t, Shapiro–Wilk, Pearson correlation, reliability analyses, and Kruskal–Wallis test were used.ResultsThe study population included 110 nerves from 55 asymptomatic participants (median age, 37.0 years; age range, 16–63 years; 29 [52.7%] women). There was a statistically significant difference between the DBRN angle in maximal supination and maximal pronation (Reader 1: 95% CI: 5.74, 8.21, p < 0.001, and Reader 2: 95% CI: 5.82, 8.37, p < 0.001). The mean difference between the angles in maximal supination and maximal pronation was approximately 7° for both readers. ICC was very good for intraobserver agreement (Reader1: r ≥ 0.92, p < 0.001; Reader 2: r ≥ 0.93, p < 0.001), as well as for interobserver agreement (phase 1: r ≥ 0.87, p < 0.001; phase 2: r ≥ 0.90, p < 0.001).ConclusionThe extremes of the rotational movement of the forearm affect the longitudinal morphology and anatomic relationships of the DBRN, primarily demonstrating the convergence of the nerve towards the SASM in maximal pronation and divergence in maximal supination.

SUDDEN MONOCULAR VISION LOSS AFTER SNEEZING AS CAPTURED ON WIDEFIELD SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY.

We report an unusual case of likely combined retinal artery occlusion and retinal vein occlusion after a sneeze. Widefield swept-source optical coherence tomography-angiography was used to analyze retinal changes at one-month follow-up. The patient reported visual symptoms in his left eye immediately after sneezing five times in a row. Fundus examination showed an embolus along the superior arcade. Stroke workup revealed moderate carotid artery stenosis and a subtherapeutic INR. At one-month follow-up, fundus photography and swept-source optical coherence tomography-angiography were obtained. Fundus photography showed superior retinal whitening and arteriole attenuation, an inferior perifoveal cotton wool spot, and inferotemporal intraretinal hemorrhages. Swept-source optical coherence tomography-angiography showed loss of the deep capillary plexus superiorly and inferotemporally, most consistent with combined retinal artery and retinal vein occlusion. We report the first case of sneeze-induced combined retinal artery and retinal vein occlusion. The retina is a uniquely accessible window that provides insight into human physiology, and swept-source optical coherence tomography-angiography is a powerful tool that can give further insight into the pathophysiology of an occlusion.

EVALUATION OF RETINAL DISPLACEMENT FOLLOWING PRIMARY SCLERAL BUCKLING FOR MACULA-INVOLVING RHEGMATOGENOUS RETINAL DETACHMENT.

To evaluate the incidence and degree of retinal displacement following scleral buckling surgery for macula-involving rhegmatogenous retinal detachment. Retrospective interventional case series comprised of patients treated with primary scleral buckling procedure without gas tamponade for macula-involving rhegmatogenous retinal detachment and imaged postoperatively with fundus autofluorescence imaging between June 1, 2016 and July 25, 2021. Clinical notes, operative reports, fundus autofluorescence photographs, and optical coherence tomography images were reviewed. The presence and degree of retinal displacement were recorded. Twelve eyes of 11 patients were included. One (8%) eye with an epiretinal membrane demonstrated 0.1 mm of retinal displacement along the superior arcade and in the superotemporal periphery. The remainder of eyes (92%) did not show any identifiable signs of retinal displacement. Retinal displacement does not seem to be a frequent complication of primary scleral buckling surgery for macula-involving rhegmatogenous retinal detachment.

Rapidly Progressed Tractional Epiretinal Membrane after Intrascleral Intraocular Lens Fixation

Purpose: To report a case of a tractional epiretinal membrane that rapidly progressed after intrascleral intraocular lens (IOL) fixation (Yamane technique).Case summary: A 59-year-old male presented with acute-onset decreased visual acuity in the left eye, which occurred 2 days previously. He was diagnosed with IOL dislocation, and underwent vitrectomy and intrascleral IOL fixation following dislocated IOL removal. Choroidal detachment related to ocular hypotony was checked for 1 day after surgery, but there were no signs of leakage at the wound. Two months after the surgery, a tractional epiretinal membrane was present in the superior arcade. and cystoid macular edema was seen on fundoscopy. The best corrected visual acuity had deteriorated to 0.6. Vessel tortuosity and cystoid macular edema deteriorated due to progressive tractional epiretinal membrane 3 months after the surgery, while visual acuity decreased to 0.2. The tractional epiretinal membrane and internal limiting membrane were removed through secondary vitrectomy. Visual acuity recovered to 0.6 1 month after the surgery, and remained stable thereafter.Conclusions: We report this case because there have been no previously reported cases of rapidly progressing tractional epiretinal membrane after application of the Yamane technique.

Prevalência de cárie dentária em jovens de 18 anos

1035 students in third grade of secondary school, in São Luís, the capital of Maranhão, Brazil, were examined. The mean age of them was about 18 years old. Utilizing a plan mirror and explorers number 5, each student in the study received a clinical dentel examination for diagnosing caries prevalence, through the DMF index and its components, by half maxilla and half jaw. In 99,50 per cent of the population studied, an average of caries incidence was 12,37 DMF by person and dental caries reached 44,31 per cent of erupted teeth. The highest caries incidence was on the superior arcade, in special in the left half maxilla. On the average, each student had 4,68 lost teeth; 4,72 with caries; and 2,87 restered. 15,10 per cent did not have removed teeth and 50,10 per cent needed at least, dental extraction. 45,50 per cent did not have restoretion.

Traumatic Branch Retinal Vein Transection and Spontaneous Reanastomosis

A 36-year-old man presented for an inferior scotoma in the left eye 2 weeks after being hit in that eye by another player’s finger while playing basketball. Snellen visual acuity was measured at 20/20. Dilated fundus examination of the left eye revealed preretinal and intraretinal hemorrhages, as well as cotton wool spots along the superior arcade (Fig A). Fluorescein angiography demonstrated branch retinal vein transection with early filling of the proximal segment and delayed filling of the distal segment (Fig B).

Ophthalmic manifestations of congenital protein C deficiency: a case report and mini review

BackgroundHomozygous protein C (PC) deficiency is a potentially fatal disease with ocular blinding presentation or sequela.Case presentationA 5 month-old boy was presented for evaluation of leukocoria. He had a history of frequent bruises and PC deficiency, treated with warfarin.His intraocular pressure was normal. In the left eye leukoma with anterior segment dysgenesis, shallow anterior chamber, and cataract were observed. Fundus was not visible. B-scan revealed a closed funnel retinal detachment. His right eye had a normal anterior segment and a thin retina with anomalous retinal vascular branching at equator and peripheral retina. A fibrovascular tuft on the optic nerve head with induced traction on superior arcade was visible. Total loss of a and b wave of both were appreciated in electroretinography (ERG). Fluorescein angiography (FA) showed very severe leakage at the junction of the vascularized and non-vascularized retina and optic nerve head. Favorable outcome was achieved with lasering of avascular retina in the right eye.ConclusionThe potential for protein C deficiency should be assessed in all infants with leukocoria, anterior segment dysgenesis, retinal detachment and retinal dysplasia. Early diagnosis could save the child’s life and vision.

CYTOMEGALOVIRUS RETINITIS WITH BELATACEPT IMMUNOSUPPRESSION

To report two cases of cytomegalovirus (CMV) retinitis in renal transplant patients after conversion to belatacept immunosuppression. Case report. Case A was a 41-year-old African American man with no ocular history, chronic hepatitis B infection on entecavir, status-post living relative renal transplant for end-stage renal disease secondary to IgA nephropathy presented with a chief complaint of "blurry vision" in his right eye. Fundoscopic examination of the right eye revealed perivascular retinitis of the superior arcade extending temporally and a lesion nasal to the optic disk. The patient was diagnosed with CMV retinitis with macular involvement. Case B was a 52-year-old woman with an ocular history significant for bilateral vein occlusions treated with laser, and a medical history of hypertension, hyperlipidemia, and end-stage renal disease secondary to hypoplastic kidney status-post deceased donor renal transplant presented with one week of blurred vision in the right eye. Fundoscopic examination of the right eye revealed macular star configuration of exudates, as well as subretinal fibrosis temporal to the macula. Fundoscopic examination of the left eye showed Grade 4 vitreous haze and multiple areas of retinal whitening and hemorrhage, consistent with CMV retinitis infection. The patient was diagnosed with bilateral CMV retinitis, with macular involvement in the right eye. Renal transplant patients converted to belatacept immunosuppression may be at an increased risk for herpes virus infection, and thus herpes virus retinitis. Although the degree of risk remains uncharacterized, patients on belatacept therapy who are at the high risk of CMV infection (i.e., donor-positive/recipient-negative patients) should be counseled on the presenting signs and symptoms of CMV retinitis. In these cases, clinicians should also consider regular monitoring of serum CMV titers or continuation of antiviral prophylaxis.

Understanding the structural changes following photodynamic and transpupillary thermotherapy for choroidal hemangioma using optical coherence tomography and optical coherence tomography angiography.

Purpose:To study optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A) features of circumscribed choroidal hemangioma (CCH) following treatment with photodynamic therapy (PDT) and transpupillary thermotherapy (TTT).Methods:A retrospective chart review of consecutive patients treated for CCH over 2 years (May 2016–April 2018). The investigations, in addition to comprehensive eye examination, included color fundus photography, B-scan ultrasonography, OCT, and OCT-A.Results:The study included 16 eyes of 16 patients (9 males and 7 females). The mean age at presentation was 43.5 ± 9 years (range 33–62 years). Macula (n = 6) and superior arcade (n = 5) were the common tumor locations. Twelve eyes received multiple treatment sessions: TTT (seven eyes; mean 2.4 sessions) and PDT (five eyes; mean 2 sessions). Four eyes were observed because vision was not threatened. Pretreatment OCT features were Bruch's membrane atrophy (15 eyes), retinal pigment epithelial atrophy (13 eyes), outer retinal abnormalities (12 eyes), and macular subretinal fluid (12 eyes). Pretreatment OCT-A features were complete loss of choriocapillaris (16 eyes), irregularly arranged fine arborizing vessels (11 eyes), and more than 50% signal void hyporeflective areas (12 eyes). Posttreatment OCT-A showed persistence of choriocapillaris loss, flat scar with fibrosis and thinning of choroid in all eyes treated with TTT, and persistence of deeper choroidal vessels and no loss of choriocapillaris in eyes treated with PDT.Conclusion:OCT and OCT-A help understand the structural outcome following PDT and TTT in circumscribed choroidal hemangioma.

Cuticular drusen associated with aneurysmal type 1 neovascularization (polypoidal choroidal vasculopathy)

BackgroundAneurysmal type 1 neovascularization (AT1) is a term recently introduced to better describe the aneurysmal dilatation that may arise from neovascular lesions, more commonly known as polypoidal choroidal vasculopathy. The proposed term, AT1, includes an expanded clinical spectrum of aneurysmal (polypoidal) lesions observed in both different ethnicities and associated with varied clinical phenotypes.Case presentationA 61-year-old woman of European descent was referred for a new, asymptomatic retinal hemorrhage found on routine examination. Ophthalmoscopy revealed cuticular drusen in both eyes best appreciated on fundus autofluorescence, and a hemorrhagic retinal pigment epithelium detachment above the superior arcade in the right eye. In the fellow eye, a reddish appearing pigment epithelial detachment was noted nasal to the optic nerve. Indocyanine green angiography showed findings of AT1 in both eyes. Optical coherence tomography angiography showed intrinsic flow signal within the aneurysmal lesions.ConclusionsEyes with cuticular drusen may develop AT1 which, to our knowledge, has not been described. This is an important observation because the documented coexistence of AT1 in the setting of a variant of age-related macular degeneration lends supports to this new understanding of AT1 as a growth pattern of neovascular tissue proliferating between the RPE and Bruch membrane, rather than as a distinct disease entity.

Branch Retinal Artery Occlusion After Coil Embolization of a Paraclinoid Aneurysm

The authors report a case of a 48-year-old woman with a branch retinal artery occlusion after the neurosurgical coiling of a paraclinoid aneurysm. Clinical examination revealed a Hollenhorst plaque at the bifurcation of the inferior arcade and at a branch of the superior arcade with associated retinal whitening in the right eye. Follow-up examination at 8 months demonstrated improved visual acuity with near complete resolution of the retinal infarction but a persistent inferior Hollenhorst plaque. This case illustrates a retinal artery occlusion as a possible complication of paraclinoid aneurysmal coiling procedure.

Idiopathic Sclerochoroidal Calcification

Sclerochoroidal calcification is a rare ocular condition characterized by multifocal, yellow-white elevated fundus lesions typically located in the superotemporal quadrant along the superior arcades. The pathology of calcification can be classified as dystrophic, metastatic, or idiopathic. Vision-threatening complications may arise, such as choroidal neovascular membrane and serous retinal detachment. The pathogenesis of sclerochoroidal calcification remains unclear. A 72-year-old Caucasian male patient presented to the clinic for routine examination. Fundus evaluation revealed bilateral, multifocal, pale yellow elevated lesions in the superotemporal fundus. Ultrasonography showed a focal area of hyper-reflectivity located in the posterior retina of both eyes, and optical coherence tomography showed an intact retina overlying the elevated lesions in the choroid. Systemic evaluation for dystrophic and metastatic calcification was negative, and the patient was diagnosed with idiopathic sclerochoroidal calcification. It is important to distinguish sclerochoroidal calcification from other conditions to prevent unnecessary intervention. Calcification of body tissues warrants a systemic evaluation, including screening for calcium and phosphorous levels, to rule out underlying systemic disease. If a biochemical abnormality is discovered, it can be appropriately treated with supplements. If calcification is deemed idiopathic, then annual dilated examinations are recommended to monitor the fundus lesions. Visual prognosis for sclerochoroidal classification is good, as the lesions are typically located away from the macula and foveal encroachment is rare.

Retinal structure in vitamin A deficiency as explored with multimodal imaging

To define the retinal structural abnormalities in a patient with vitamin A deficiency. The patient had a complete ophthalmic examination, electroretinography (ERG), short-wave fundus autofluorescence (SW-AF) and spectral domain optical coherence tomography (SD-OCT) imaging. Serum vitamin A levels were measured. A 63-year-old man with alcoholic cirrhosis, sclerosing cholangitis and chronic pancreatitis experienced blurred vision and nyctalopia for over a year. There was no family history of eye disorders or consanguinity. His best-corrected visual acuity was 20/20 in each eye; color vision as determined with Ishihara color plates was normal in each eye. Anterior segment examination was unremarkable. He was pseudophakic in both eyes. Standard ERGs showed non-detectable rod function, a cone-mediated dark-adapted response to the standard flash and borderline reduced cone function. Serum vitamin A levels were below 0.06 mg/L (normal 0.3-1.2 mg/L). Fundus examination revealed numerous round yellow-white lesions along the superior arcade and nasal to the optic nerve in both eyes. These lesions were hypoautofluorescent on SW-AF. SD-OCT cross sections demonstrated that they were focal disruptions distal to the ellipsoid band of the photoreceptors with hyperreflective images bulging up the ellipsoid and region. The retinal pigment epithelium and the inner retina appeared intact. Limited and gradual vitamin A supplementation for over a month (20 000 IU/day) led to a dramatic improvement in retinal function and to the resolution of the symptoms. The retinal lesions remained unchanged. Imaging of this patient with nyctalopia and severe rod dysfunction suggests that the retinal white lesions known to occur in vitamin A deficiency localize to the photoreceptor layer, particularly the outer segment. On OCT, they are reminiscent of lesions observed in genetic diseases with retinoid cycle dysfunction and of drusenoid subretinal deposits, an abnormality commonly associated with age-related macular degeneration.

Secondary choriocapillaritis in infectious chorioretinitis

To analyse the indocyanine green angiography (ICGA) patterns of hypofluorescence that are compatible with choriocapillaritis that occur secondarily to toxoplasmic retinochoroiditis (ToRC), ocular tuberculosis (including tuberculous choroiditis, TuCR and multifocal serpiginoid choroiditis, TMSC) and syphilitic chorioretinitis (SyCR). This was a single centre, retrospective case review study. Patients with a diagnosis of ToRC, TuCR, TMSC or SyCR were identified, their charts were reviewed and fundus photographs, fluorescein angiography (FA) and ICGA pictures were assessed. Indocyanine green angiography was performed at the initial presentation in 63 of the 105 patients with ToRC, in 37 of the 38 patients with TuCR, in six of six patients with TMSC and in two of four patients with SyCR. The following four ICGA patterns indicated choriocapillaritis: extension of hypofluorescence beyond the hypofluorescence of the actual infectious focus as seen on fundus photography or FA (seen only in ToRC and TuCR); small dark dots around the infectious focus (seen only in ToRC); multiple 'confetti-like' hypofluorescent areas or hypofluorescent geographical confluent areas (seen only in TMSC); and widespread areas of nonperfusion visible only in ICGA (seen only in SyCR). Patients with secondary choriocapillaritis have distinct typical ICGA findings. ICGA is thus an important diagnostic tool that can provide an explanation for otherwise obscure visual loss and that might have diagnostic value for specific conditions like ToRC and SyCR.

Racemose hemangioma type 2: the first case report from the Middle East

Retinal arteriovenous malformations are rare and most are reported to be asymptomatic. We report an 11-year-old boy who attended for blunt trauma to his eye. The first ophthalmologic examination was performed in Nikookari Hospital Eye Emergency Room. Visual acuity was 20/20 and relative afferent pupillary defect was negative in both eyes. Ophthalmoscopic examination revealed multiple massive dilated retinal vessels in the superior arcade of the right eye. The arteriovenous malformation was not associated with exudation, hemorrhage or abnormal pigmentation. The left eye examination was unremarkable. We performed fluorescein angiography and brain magnetic resonance imaging (MRI). In the right eye fluorescein angiography, the malformation was not associated with leak or edema. The left eye fluorescein angiography was unremarkable. Brain MRI was unremarkable. After 16months follow-up, there were no symptoms. This is the first case report from the Middle East region. To the best of our knowledge, retinal arteriovenous malformation has rarely been reported in children. Previously published literature suggests that these malformations may become complicated in time. Brain MRI is strongly recommended because of the possibility of Wyburn-Mason syndrome.

Retinal and optic nerve oxygenation and carbonic anhydrase inhibition

Abstract Purpose To study the effects of carbonic anhydrase inhibition on porcine retinal and optic nerve oxygenation under physiological conditions and in experimental models of ischemia. Methods Polarographic oxygen electrodes were used to measure the oxygen tension in the vitreous 500 microns in front of the optic nerve and retina. Retinal ischemia was produced by diathermia of the superior arcade vein, producing a branch retinal vein occlusion, BRVO. Optic nerve ischemia was produced by intravenous administration of 100 mg Indomethacin intravenously. Results One week after induction of BRVO, the oxygen tension over BRVO affected retina was significantly decreased by 29%. Administration of the carbonic anhydrase inhibitor dorzolamide (500 mg) caused a significant increase in the oxygen tension over BRVO affected retina, and in effect restored this tension to normal values (n=5). Intravenous administration of 300 mg Indomethacin caused a decrease of optic nerve oxygen tension by 41%. Subsequent administration of 500 mg dorzolamide increased the optic nerve oxygen tension, albeit not to normal levels (n=6). Conclusion Carbonic anhydrase inhibition increases the oxygen tension in the retina and optic nerve. In BRVO affected retina, carbonic anhydrase inhibition restores oxygen tension to normal levels.