ROPARD - The Association for Retinopathy of Prematurity and Related Diseases

Peripheral ablation for retinopathy of prematurity is based on the data from the Retinopathy of Prematurity Cryo Study.  The Retinopathy of Prematurity Cryo Study suggests the use of cryo ablation in the periphery.  With the advent of the laser indirect ophthalmoscope, cryotherapy is a less desirable mode of peripheral ablation.  In the situation where no other treatment is available, cryotherapy perhaps has a place, but where both therapies are available, laser ablation is much superior, as cryotherapy leads to an effusion following treatment that can be damaging to the retina.  Treatment with laser is best done with the red diode laser, although green argon laser can also be used.  The concern with the green laser is that absorption in and around the lens by the tunica vasculosa lentis may lead to cataract formation. 

The treatment pattern for laser is important.  A near confluent treatment pattern yields the best result.  The photograph of the laser pattern in this module shows a laser pattern that is too widely spaced.  The laser spots should be placed approximately one-half of the laser spot dimension apart.  This pattern should be loosened however in the horizontal meridians to avoid anterior segment ischemia, which can have varying degrees following treatment ranging from cataract presentation to extreme hypotony and phthisis resulting after a period of this hypotony.  The child may need a second or sometimes even a third laser treatment.  These cases however are rare constituting probably fifteen percent at most of the eyes treated with peripheral ablation.

The intervention for peripheral ablation recommended by the Retinopathy of Prematurity Cryo Study was five clock hours of contiguous stage 3 disease or eight clock hours of discontiguous stage 3 disease.  Both of these must be accompanied by plus disease and plus disease is defined as dilated tortuous arteries and veins in the posterior pole.  Plus disease we now know evolves from the periphery and extends to the posterior pole due to the arteriole venous communication through the shunt in the junction tissue between the avascular and vascularized retina.  The child may present with findings that are less than typical.  These findings can include a very vascularly active eye with exuberant plus disease in the posterior pole.  Eyes such as this may benefit from laser ablation even though they may not be at what might be considered by the observer as the standard stage 3 threshold. 

These eyes with extremely active plus disease suggest an extraordinarily active VEGF eye and down regulation of the VEGF needs to be achieved in order to preserve any level of vision in this type of eye.  The montage in this module does show such an extremely vascularly active eye.  Eyes like these uniformly go on to retinal detachment and blindness without early treatment.  The anterior segment can show dilated vessels or rubeosis iridis is not frank neovascularization, but represents again a manifestation of absence of involution of tunica vasculosa lentis due to the very high level of VEGF. 

Occasionally, this tunica vasculosa lentis may make it difficult to get good examination into the posterior pole or even laser treatment for the peripheral retina.  If that is the case, pharmacologic dilatation of the pupil with a pledeget may be helpful or sometimes pressure on the globe for scleral depression sometimes will result in breaking the pupillary aperture open.  Again, in these eye it is perhaps more important to use the red diode than in others to avoid lenticular opacity.