Dear Editor,

We read with interest the article on variations in the morphology of retinopathy of prematurity (ROP) [1]. We found the mention of a poorly developed capillary bed present in an already vascularised retina particularly interesting. We have noted a similar case that might corroborate this finding.

A male infant of birth weight 1700 gms, 34 weeks gestational age was examined at 37 weeks post-conceptional age. The retinal vascularisation stopped at anterior zone II bilaterally. The right eye had a preretinal haemorrhage (Fig. 1A). The left eye had mild plus disease with superficial haemorrhages (Fig. 1B), with multiple demarcation lines and intervening pockets of avascularity, at different levels both temporally and nasally. Vessels were seen to connect the vessels adjacent to the posterior demarcation lines to small brush like vessels that in turn originated from the anterior demarcation lines (Figs 1C and 1D). The picture was suggestive of persistent borderline ischaemia in areas despite the presence of retinal vascularisation.

[View full-size figures 1A-D]

Figure 1A. Colour frozen image of the right eye taken with the video indirect ophthalmoscope. The fundus images seen through the 20D condensing lens. Pre-retinal haemorrhage about 1 disc diameter in size in the superotemporal arcade of zone 1 in the right eye is seen.
Figure 1B. Colour frozen image of the left eye taken with the video indirect ophthalmoscope. Mild plus disease in the left eye with small haemorrhages (white arrows) are seen.
Figure 1C. Colour frozen image of the left eye taken with the video indirect ophthalmoscope showing the superonasal quadrant. The mound seen is that of the scleral depression (black arrow). * represents the intervening pocket of avascularity. Two demarcation lines at multiple levels are obvious. The white arrow head represents the posterior demarcation line. The black arrow head represents the anterior demarcation line. The vascularised status of the posterior retina is clear as seen by the vessels adjacent to the white arrow head. Multiple brush like vessels are seen emerging from the anterior demarcation line. The white arrow represents a small vessel connecting these brush like vessels to the more posterior vessel.
Figure 1.D. Colour frozen image of the left eye taken with the video indirect ophthalmoscope showing the inferotemporal quadrant. The white arrow head represents the posterior demarcation line. The black arrow head represents the anterior demarcation line. * represents the intervening pocket of avascularity. The mound seen is that of the scleral depression (black arrow). Vessels are seen to cross over from the posterior to the anterior retina over these demarcation lines. One such vessel is represented by the white arrow. The intervening pocket of avascularity is uncrossed by the retinal vessels.

The intervening avascular pockets could correspond to the poorly developed capillary bed being present in an already vascularised retina as noticed by Schulenberg et al. [1]. These findings are entirely different from that reported in the CRYO-ROP study [2].

The right eye preretinal haemorrhage resolved spontaneously after two months, while the left eye picture was status quo. A case series of late retinal detachment with multiple fibrotic ridges in ROP has been presented previously [3]. We thought that our findings probably represented the early stage of those cases. Hence, the patient underwent laser photocoagulation to the avascular retina and to the intervening pockets of avascularity in the left eye. Follow up after a week, revealed disappearance of the plus disease and avascular pockets. The infant had complete retinal vascularisation when last seen at 6 months of follow up.

References

1. Schulenberg WE, Tsanaktsidis G. Variations in the morphology of retinopathy of prematurity in extremely low birth weight infants. Br J Ophthalmol 2004;88: 1500-1503.

2. Cryotherapy for Retinopathy of Prematurity Cooperative Group. Multicenter trial of cryotherapy for retinopathy of prematurity. One-year outcome-structure and function. Arch Ophthalmol 1990;108: 1408-1416.

3. Tawansy KA et al. Smouldering ROP, presented at ARVO Annual Meeting, 2004.