Various areas in research have reached different stages of progress along this research ladder.

Gene Therapy:
Dr Debora Faber has established proof of principle in gene replacement in a mouse model with a PDE recessive mutation. Progress towards human trials are expected within a short time.

Phase 1 clinical trials will start this year using Fibroblast transplants into any part of the body to metabolise and lower ornothine levels in Gyrate Atrophy patients. These patients have a raised ornithine level and were previously treated with a low ornithine diet.

Pharmaceutical Interventions:
These various agents will not address the root cause of the condition but may slow or halt the disease process. Various agents being studied are:- Neuron Survival factors, Vitamins, Antioxidants, Anti-Apoptotic agents and Fatty acids and Lipids.

Vitamin A:
A six year clinical trial showed evidence that 15 000 IU Vitamin A Palmitate slowed degeneration in Retinitis Pigmentosa and Usher Syndrome (Adults).

Risk Factors:
Pregnancy - foetal abnormality
Liver toxicity
Skin allergies and reaction to sunlight
Smoking - a substantial increased risk to smokers developing lung cancer


Vitamin A and Sorsbys Fundus Dystrophy:
Extremely high doses of Vitamin A showed improvement in vision. More studies are needed to answer the question of safety and if the improvements last.

DHA:
Dr David Birch of Texas is studying the effect of DHA supplementation in x-linked RP patients.

Neuron Survival Factors:
Drs Matt Lavail and R Steinberg have established proof of principle that Axokine slows retinal degeneration particularly in animal models with a PDE gene defect. Phase 1 human clinical trials have been approved and begin shortly. This progress has been accomplished by collaboration of the American Foundation Fighting Blindness who funded the basic proof of principle trials; Regeneron - the company which developed Axokine; The National Eye Institute of America who will conduct the Phase 1 clinical trials for safety.
The problem of a suitable drug delivery system for this and other interventions received critical attention at the Congress.
A special ½ day workshop was devoted to this. A whole new field of researchers working on drug delivery to the eye in other diseases are now bringing their expertise into retinal degeneration research.

Cell Transplantation:
The two areas of Photoreceptor and Retinal Pigment Epithelium (RPE) transplants were discussed. The Photoreceptor transplants have not shown much viability but work progresses in various laboratories. RPE transplant and full thickness retinal sheets seem to show more promise. RPE transplantation, if successful, may offer hope to Age-related Macular Degeneration patients. The American Foundation Fighting Blindness is now funding the first clinical trials for RPE cell transplantation with Dr Marco Zarbin.

Visual Prosthesis:
Retinal degeneration is marked by the death of the light sensitive photoreceptor cells. The underlying ganglion cells which relay the message to the optic nerve are however relatively intact. It is therefore theoretically possible to implant a synthetic device to bypass the photoreceptors. 5 groups, 3 in America and 2 in Germany, are working on ways to do this. Some encouraging results have been shown.

(Editor's comments: Thanks to Dr Gerry Chader for his notes from which I copied liberally - any errors are mine, not his.)