No evidence for deterioration in diabetic retinopathy during hyperbaric oxygen therapy, but some evidence for persistent myopia.

 

Clinical Bottom Line:

1. No evidence that HBO is associated with deterioration in diabetic retinopathy

2. HBO is associated with a myopic shift and this persists for at least 3 months

 

Appraised by: Michael Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney, Australia ; Friday, 18 January 2002 Email: m.bennett@unsw.edu.au

 

Three-part Clinical Question: For patients with evidence of diabetic retinopathy, does the application of hyperbaric oxygen result in any aggravation of the retinopathic changes?

Search Terms: Diabetic retinopathy, diabetes mellitus

 

The Study:

Double-blinded concealed randomised controlled trial with intention-to-treat.

The Study Patients:  Diabetic patients with evidence of background diabetic retinopathy and who were scheduled to take part in an RCT of hyperbaric therapy for diabetic ulcers.

Control group (N = 8; 8 analysed): Hyperbaric air at 2.4 ATA for 90 minutes daily for 30 days over 6 weeks.

Experimental group (N = 7; 7 analysed): 100% oxygen on the same regimen as above.

 

The Evidence:

Non-Event Outcomes                       Time to outcome                Airgroup          HBO group              P-value

Spherical equivalent                                   3 months                        R eye 0.13         R eye -0.69

                                                                                                      L eye 0.75         L eye -1.04

 

 Myopic shift R eyes                              3 months                                                                                       0.02                                                                         

                       L eyes                                                                                                                                    0.01

 

Ocular blood flow

Tonometry                                                   3 months                         No change          No change

Fluoroscein Angiography

Retinal Photography

 

Comments:

1. Difficult study to interpret. It is not clear if patients had persistent reduction in visual acuity for the three months follow-up of the study. This would be an important finding. The authors suggest a structural change in the lens.

2. Small study with low power.

3. Probably the same patients as other studies by similar authors in diabetic ulcer patients.

4. Abstract only.

 

Expiry date:  October 2003

 

References:1. Jalabi MW, Abidia A, Kuhan G. The safety and effect of hyperbaric oxygen therapy in patients with diabetic retinopathy - a double-blind randomised-controlled trial. Undersea and Hyperbaric Medicine 2001; 28(suppl):57.

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