Ocular Biometric Changes Associated With Hyperbaric Oxygen Therapy

Hyperbaric oxygen therapy (HBOT) involves targeted application of oxygen at specific pressures. Ocular complications of HBOT have been reported, including cataract formation and progression, as well as myopic shift. These have been attributed to hyperbaric conditions or possible oxygen toxicity in the setting of higher exposures and longer treatment duration. We report a case of a patient with pre-existing visually significant cataracts who is interested in pursuing surgical cataract surgery in the setting of concurrent HBOT treatment for wound healing of his extremities. We report the patient’s biometric changes over the course of HBOT treatment and suggest caution in the timing of cataract surgery in patients undergoing HBOT.  

Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States

A 40-year-old male was referred for cataract evaluation. Medical history included type 2 diabetes mellitus diagnosed 8 years prior, complicated by a recent episode of osteomyelitis necessitating amputation of his right foot. He underwent 38 sessions of HBOT over 63 days for wound healing at 2.0 atmospheres absolute (ATA) for 109 minutes per treatment. At the time of his ophthalmic assessment, the patient was at day 4 of HBOT. His best-corrected visual acuity was 20/200 in each eye. Examination revealed bilateral cortical cataracts and mild non-proliferative diabetic retinopathy. Phacoemulsification with intraocular lens implantation (CE-IOL) of both eyes was planned. Since HBOT may affect lens measurements, serial biometries were recommended and CE-IOL was scheduled three months after HBOT to ensure measurement stability. Initial biometry after 5 sessions of HBOT showed right and left axial lengths (AL) of 24.06mm and 23.93mm, respectively. Anterior chamber depth (ACD) was 3.82mm and 3.80mm. Lens thickness (LT) was 3.26mm in both eyes. Effective lens position (ELP) 5.13mm and 5.11mm. Biometry done at after 37 sessions of HBOT showed right and left AL of 24.07mm and 23.92mm, respectively. ACD was 3.78mm and 3.75mm. LT was 3.28mm and 3.29mm. ELP was 5.11mm and 5.09mm. Biometry done 4 days after completion of therapy showed right and left AL of 24.05mm and 23.92mm, respectively. ACD was 3.77mm and 3.75mm. LT was 3.28mm and 3.23mm. ELP was 5.10mm and 5.06mm.

Patients undergoing systemic HBOT are at risk of biometric changes. In this patient, ACD and ELP decreased in both eyes, and LT increased in the right and fluctuated in the left. Using the Barrett formula aiming for a plano target, the IOL that would have been selected for implantation varied by 0.5 diopters in both eyes. These findings support that HBOT induces changes in lens turbidity. Serial biometric testing can assist with pre-operative planning in order to optimize intraocular lens selection in this patient population. Further studies are needed to assess these changes over time in a large cohort and to better establish the mechanism of these changes.