If it is true that...

Degeneration of the retina is the main cause of blindness in old people

and

The retina becomes easier to injure by light in old age for some of the same reasons that the infant's retina is susceptible

Then it must be true that...

All organs are subject to the same kinds of damage

If it is true that...

Stress, a "respiratory defect", and free radical damage are common factors in disease and aging

Then it must be true that...

All organs are subject to the same kinds of damage