Reversibility of retinal ischemia due to central retinal artery occlusion by hyperbaric oxygen

Abstract

PurposeIschemic retinal damage can be reversed by hyperbaric oxygen therapy (HBOT) as long as irreversible infarction damage has not developed. However, the time window till irreversible damage develops is still unknown. The study aim was to evaluate the effect of HBOT and determine possible markers for irreversible retinal damage.Materials and methodsRetrospective analysis of 225 patients treated with HBOT for central retinal artery occlusion (CRAO) in 1999–2015. One hundred and twenty-eight patients fulfilled inclusion/exclusion criteria: age >18 years, symptoms <20 hours, and best-corrected visual acuity (BCVA) <0.5 logMAR.ResultsTime delay from symptoms to treatment was 7.8±3.8 hours. The BCVA was significantly improved after HBOT, from 2.14±0.50 to 1.61±0.78 (P<0.0001). The proportion of patients with clinically meaningful visual improvement was significantly higher in patients without cherry-red spot (CRS) compared to patients with CRS at presentation (86.0% vs 57.6%, P<0.0001). The percentage of patients with final BCVA better than 1.0 was also significantly higher in patients without CRS vs patients with CRS at presentation (61.0% vs 7.1%, P<0.0001). There was no correlation between CRS and the time from symptoms. HBOT was found to be safe, and only 5.5% of patients had minor, reversible, adverse events.ConclusionHBOT is an effective treatment for non-arteritic CRAO as long as CRS has not formed. The fundus findings, rather than the time delay, should be used as a marker for irreversible damage.

Hyperbaric Oxygen Therapy in Retinal Arterial Occlusion: Epidemiology, Clinical Approach, and Visual Outcomes

“…It may be an option to consider also because there is no approved treatment yet for RAO, the current alternative therapies do not have similar outcomes and without treatment there is little chance of visual improvement by the natural history [1,2,4]. e results of our study are in agreement with the literature and other studies, as patients responded well to HBOT, showing a clinically signi cant BCVA improvement in 61.5% ( = 8) of cases in the total sample, of which 62.5% ( = 5) belongs to the CRAO group and 37.5% ( = 3) belongs to the BRAO group [1,2,11,17] [11]. Also, an improvement from HM to CF has been described to be clinically relevant, and corresponds to an interval of 4 lines (in 0.1 log-unit steps) [2,16].…”

“…In this context, the authors documented that CRS can be used as a marker for irreversible anoxic retinal damage for patients candidates for HBOT. ey even highlight that it, rather than the time delay from symptoms onset, should be used as the most important marker for treatment success [11]. e safety of HBOT is another factor that supports this therapeutic option.…”

“…Animal models of central RAO (CRAO) have demonstrated that an ischemic insult to the retinal tissue greater than 90 minutes (min) will lead to some degree of inner retina damage and it will be irreversible if greater than 240 min [10]. As opposed to animal models, in humans there is no clear timeline until irreversible anoxic retinal damage occurs (some authors suggest elapsed time of around 6-6.5 hours, h) [11].…”

Hyperbaric Chamber and Its Ophthalmic Applications

“…11 Hyperbaric oxygen therapy is considered acceptable, safe and effective when given early, best results of restoration of vision have been found if oxygen therapy is given within 8 hours 12,13 of onset of visual loss and continued till restoration of central retinal artery blood flow, though good results have also been seen if HBOT is administered within 24 hours [14][15][16] and also in CRAO cases without development of cherry red spot. 17 The aim of treating CRAO with HBOT is to supply oxygen to the inner layers of the retina with sufficient partial pressure of oxygen until blood flows through the central retinal artery again. Administration of carbogen (95% oxygen and 5% carbon dioxide), intraocular pressure lowering therapy, ocular massage and paracentesis may also be given though the efficacy is debatable but better restoration of visual acuity has been found hemodilution and hyperbaric therapy.…”

Management of central retinal artery occlusion following successful hyperbaric oxygen therapy: case report

“…Loss of vision is such a disabling condition that every reasonable therapeutic measure should be undertaken to prevent the vision loss from becoming permanent. Hyperbaric oxygen therapy (HBO 2 ) may be useful in reversing vision loss in at least some cases of CRAO [3][4][5][6][7][8][9][10][11][12].…”