THE EFFECT OF HYPERBARIC OXYGEN THERAPY ON RETINA, CHOROIDAL THICKNESS, AND CHOROIDAL VASCULARITY INDEX

Shape-recoverable chitosan/sodium alginate aerogels with sustained oxygen release and antibacterial activity for diabetic wound healing

Wounds in diabetic patients are often inhibited in angiogenesis and extracellular matrix synthesis due to insufficient oxygen supply, leading to prolonged healing time. Although oxygen therapy has been shown to promote the healing of chronic wounds, its therapeutic effectiveness remains limited by high costs, complex procedures, and a lack of sustainability. In this study, we developed an aerogel composed of chitosan (CS), sodium alginate (SA), and calcium peroxide (CPO). These aerogels can absorb wound exudate and release oxygen upon contact, providing continuous oxygen delivery for over five days. The freeze-dried aerogels are soft and exhibit shape recovery properties, which facilitate enhanced oxygen transport. Furthermore, the CS/SA-CPO aerogel demonstrated strong antioxidant activity, excellent biocompatibility, and potent antibacterial properties (exceeding 99.99 %). In vivo experiments indicated that the CS/SA-CPO aerogel promotes wound healing by continuously releasing oxygen, accelerating collagen deposition, and enhancing re-epithelialization, ultimately achieving 99.65 % wound closure within 21 days. This innovative approach offers a promising strategy for managing chronic, hypoxic diabetic wounds.

A comprehensive evaluation of efficacy of hyperbaric oxygen therapy in non-arteritic central retinal artery occlusion using enhanced depth imaging optical coherence tomography

This study aimed to assess the efficacy of hyperbaric oxygen therapy (HBOT) in patients with central retinal artery occlusion (CRAO) by analyzing changes in visual acuity (VA) and enhanced depth imaging optical coherence tomography (EDI-OCT) parameters. A comparative retrospective study was conducted by reviewing the medical records of all HBO-treated RAO patients in our department and comparing them with matched RAO patients who did not receive HBO treatment. All patients treated with HBO received treatment within 7 days of the onset of visual symptoms. Baseline characteristics were compared, and VA and OCT parameters were evaluated at baseline and follow-up visits. A total of 50 eyes from 50 patients were included, with 29 eyes in the HBOT group and 21 eyes in the control group. The mean BCVA of the HBOT group at the initial visit was 2.03 logMAR, which improved to 1.55 logMAR at 6 months, with the change being statistically significant (P < 0.01), while the control group's BCVA remained almost unchanged, from 2.1 to 2.11 logMAR (P = 0.762). The central choroidal thickness increased significantly in the HBOT group over the subsequent period. The central fovea, and outer retinal layer thickness in the HBOT group were significantly greater than those in the control group at the 6-month follow-up after treatment. HBOT appears to be effective in improving VA and inducing favorable changes in OCT parameters in patients with CRAO. It helps to preserve retinal layer thickness, especially in the outer retinal layer.

Vision Crisis-Bilateral Outer Retinitis Due to Mumps Virus

PURPOSE

To report a case of mumps-associated outer retinitis, diagnostic, and therapeutic challenges associated with the disease.

METHOD

Retrospective observational case report.

RESULTS

An 8-year-old male child on presentation had a history of mumps infection following which he developed outer retinitis. Upon evaluation, he had bilateral multifocal perivascular cerebriform retinitis. MRI revealed increased uptake of contrast by bilateral parotid gland and with serum mumps IgM and IgG antibodies being raised, a diagnosis of mumps associated outer retinitis was made. In terms of treatment post-systemic steroid therapy, hyperbaric oxygen therapy was tried as a rescue therapy in this patient. Improvement in vision was noted in the left eye more than the right eye.

CONCLUSION

Hyperbaric oxygen therapy can be considered as an additional therapy to systemic steroid therapy in mumps associated retinitis. In such a situation, since there is no specific antiviral drug available for mumps infection, the most effective treatment is prevention by vaccination.

Calcium Peroxide-Based Hydrogel Patch with Sustainable Oxygenation for Diabetic Wound Healing

Nonhealing diabetic wounds are predominantly attributed to the inhibition of angiogenesis, re-epithelialization, and extracellular matrix (ECM) synthesis caused by hypoxia. Although oxygen therapy has demonstrated efficacy in promoting healing, its therapeutic impact remains suboptimal due to unsustainable oxygenation. Here, this work proposes an oxygen-releasing hydrogel patch embedded with polyethylene glycol-modified calcium peroxide microparticles, which sustainably releases oxygen for 7 days without requiring any supplementary conditions. The released oxygen effectively promotes cell migration and angiogenesis under hypoxic conditions as validated in vitro. The in vivo tests in diabetic mice models show that the sustainably released oxygen significantly facilitates the synthesis of ECM, induces angiogenesis, and decreases the expression of inflammatory cytokines, achieving a diabetic wound healing rate of 84.2% on day 7, outperforming the existing oxygen-releasing approaches. Moreover, the proposed hydrogel patch is designed with porous, soft, antibacterial, biodegradable, and storage stability for 15 days. The proposed hydrogel patch is expected to be promising in clinics treating diabetic wounds.

Hyperbaric Oxygen Therapy in Ophthalmology: A Narrative Review

Hyperbaric oxygen therapy (HBOT) has been used for the past 50 years for conditions such as decompression disease and wound healing. It has promising effects in the treatment of vision-threatening diseases, such as retinal artery occlusion, retinal vein occlusion, diabetic macular edema, and acute optic neuropathy; however, HBOT has not been approved for use in these conditions by regulatory authorities. This paper provides an overview of the theoretical effectiveness and most recent indications for HBOT in ophthalmology. The fundamental aspects of the physiology of choroidal circulation and metabolism are provided together with the clinical aspects that should be accounted for when selecting patients for this therapy. The paper also presents case reports of when HBOT was successfully implemented. The goals of this review were to explore the indications and benefits of HBOT and to evaluate the effectiveness of HBOT as an intervention in treating ophthalmology disorders. Lastly, the paper details the side-effects and discusses the safety issues of HBOT.

The effect of hyperbaric oxygen therapy on corneal endothelial structure and anterior segment parameters

PURPOSE

To assess the effect of hyperbaric oxygen therapy (HBOT) on corneal endothelial structure and anterior segment parameters in healthy eyes.

METHODS

17 eyes of 17 patients who were scheduled to receive HBOT for other than ophthalmologic indications were investigated in this prospective study. Central corneal thickness (CCT) and corneal endothelial properties were evaluated using a specular microscope. Endothelial cell density (ECD), average cell area (AVG), coefficient of variation in cell size (CV), percentage of hexagonal cells (HEX), CCT, intraocular pressure (IOP), spherical equivalent (SE), axial length (AL) and anterior chamber depth (ACD) values were measured before the HBOT, after the 1st session, and after the 20th session of therapy.

RESULTS

47% of the patients (n = 8) received HBOT because of avascular necrosis, 35% (n = 6) due to sudden hearing loss, 12% (n = 2) for diabetic foot, and 6% (n = 1) for wound infection. The mean IOP was 14,80 mmHg before HBOT, 14,20 mmHg after the 1st session, and 13,73 mmHg after the 20th session. The mean ACD was 3,38 mm before HBOT, 3,34 mm after the 1st session, and 3,16 mm after the 20th session. Although the mean IOP and ACD decreased after HBOT sessions, it was not statistically significant (p > 0.05). A significant reduction was observed in SE values after 20 sessions of HBOT compared to the values measured before HBOT (p = 0,009). The mean ECD was 2572,53 ± 261,51 cells/mm2 before HBOT, 2554,47 ± 236,13 after the 1st session, and 2563,13 ± 226,92 after the 20th session. When the corneal properties measured before and after HBOT sessions were compared, no significant difference was found in terms of CCT, ECD, AVG, CV, and HEX (p > 0.05).

CONCLUSION

We observed no significant change in CCT, corneal endothelial layer properties, and anterior segment morphology after the 1st session, and after the 20th session of HBOT. Although HBOT reduced IOP and ACD, it was not statistically significant. HBOT may lead to a significant decrease in SE values after the 20th session.

Paracentral acute middle maculopathy in a fasting patient after cataract surgery and its response to hyperbaric oxygen therapy

INTRODUCTION

Paracentral acute middle maculopathy (PAMM) is a structural optical coherence tomography (OCT) sign secondary to ischemia in the intermediate and deep retinal vascular network, characterized by hyperreflectivity in the inner nuclear layer (INL).

AIM

Our objective is to demonstrate PAMM development following uncomplicated cataract surgery, possibly triggered by fasting and dehydration. We also aim to emphasize the potential role of hyperbaric oxygen therapy in treating PAMM.

CASE PRESENTATION

A 66-year-old man with a past medical history of Neurofibromatosis type 1 and cardiovascular disease underwent uncomplicated cataract surgery in the left eye. The patient was also fasting due to Ramadan. The patient complained of very low vision during the routine postoperative examination on the third day. His-best-corrected visual acuity (BCVA) was counting fingers at 1 meter. His-anterior and posterior segment examination was unremarkable. In infrared imaging, a large hyporeflective area was observed in the parafoveal region, and structural OCT also showed increased hyperreflectivity in the middle retinal layers corresponding to the junction of INL and outer plexiform layer (OPL) involving the entire INL which suggested PAMM. Following 14 sessions of hyperbaric oxygen therapy, the patient's BCVA increased to 0.9 on the 14th day of diagnosing PAMM.

CONCLUSION

To the best of our knowledge, this is the first case representing a patient with  PAMM triggered by fasting and cataract surgery who responded positively to hyperbaric oxygen therapy. However, triggering of PAMM by fasting is entirely unproven and that this observation occurred in a highly complex case with many other possible contributing factors. Also, the triggering of PAMM by some manipulation during surgery is equally unproven.