Prevalence and Incidence of Retinoschisis, X-linked
Ophanet, who are a consortium of European partners,
currently defines a condition rare when if affects 1 person per 2,000.
They list Retinoschisis, X-linked as a "rare disease".
More information about Retinoschisis, X-linked is available from Orphanet
About prevalence and incidence statistics:
The term 'prevalence' of Retinoschisis, X-linked usually refers to the estimated population
of people who are managing Retinoschisis, X-linked at any given time.
The term 'incidence' of Retinoschisis, X-linked refers to the annual diagnosis rate,
or the number of new cases of Retinoschisis, X-linked diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.