Irish wolfhound, field use Irish setters and some other large breeds tend to have heart problems and shorter lives than smaller breeds, but size is not the only correlation in many heritable problems like lens luxation and subsequent glaucoma, or in hip dysplasia.
Breeds with the luxation problem are border collies, many terriers, Australian Cattle Dog, Brittany and some other spaniels, Elkhounds and some others. My wife's miniature fox terrier happened to include a line in which the gene was present but had not been paired with a mate that also carried the gene.

Several large breeds carry heritable hip dysplasia, but some mid-size breeds like border collies also can develop the problem.

Consciencious breeders keep careful records and try to keep clear of lineages that that might contribute genes that carry these heritable problems, but are not always successful.

The hip problem is operable, and a loved dog can have many active years after the condition is corrected.
The eye problem can result in blindness, but the other senses take over and a blind dog can play and serve as a companion even though it cannot see.

Canine medical specialists are expensive, treatments often over $1000, but if the pet has become a member of the family, the cost is borne stoically.