Retinal detachment with breaks in the pars plana.

RETINAL detachment is sometimes due to retinal breaks anterior to the ora serrata in the pars plana ciliaris. This clinical feature has previously been reported by Schepens and Bahn (1950), Schepens (1951), Dobbie and Phillips (1962), and Cox, Schepens, and Freeman (1966) in relation to retinal detachment. Weidenthal and Schepens (1966), who were able to produce retinal breaks at the pars plana in enucleated pigs' eyes, have observed that in ocular contusion the sclera expands and oscillates with a greater amplitude than the vitreous. As a result the vitreous base and attached ciliary epithelium pull away from the pigment epithelium of the pars plana. This single layer of non-pigmented epithelium is anterior to the ora serrata where the multilayered sensory retina is abruptly transformed into one layer. The internal limiting membrane, however, passes without interruption onto the pars plana while the non-pigmented and pigmented epithelium become firmly attached to each other at the ora serrata (Fine and Zimmerman, 1963). Straddling the ora is the firm attachment of the vitreous base. Clinically, peripheral retinal damage as a result of ocular contusion is most liable to occur either as a temporally located dialysis or as breaks in the upper n(asal area caused by tearing of the vitreous base from its attachment. The non-pigmented epithelium of the pars plana ciliaris may be avulsed with the vitreous base, in which case it can occasionally be seen suspended in the vitreous cavity. A variant of these two types of peripheral damage is extensive detachment of the ora serrata with retinal breaks in the detached nonpigmented epithelium of the pars plana ciliaris along the anterior border of the vitreous base. This report describes the clinical features and incidence of traumatic detachments due to breaks anterior to the ora serrata in a series of 243 primary retinal detachments.