CHAPTER 7 Retinopathy of Prematurity

Abnormalities of the Retina

Our goal in this chapter is to introduce those retinal diseases that are most commonly encountered in cytology specimens. The diagnosis of many of these lesions by cytologic techniques alone can be difficult and thorough familiarity with the tissue lesion can be very helpful.
The ocular cytologist is likely to encounter specimens from only a few retinal diseases on a routine basis. Intraocular washings from patients with diabetic retinopathy and proliferative vitreoretinopathy account for most of the specimens. Because the diagnosis is often apparent from clinical examination, some argue that it is superfluous to send the intraocular washings for pathologic examination. Indeed, only 15% of intraocular washings are diagnostic of specific diseases.[1] However, the need to exclude clinically unsuspected infectious and neoplastic disorders justifies routine processing of vitrectomy specimens. Examination of intraocular washings sometimes reveals retinal fragments. It is often difficult to diagnose specific diseases from retinal fragments seen in cytologic preparations. Other accompanying fragments usually provide clues to the diagnosis. Notable exceptions in which diseases are diagnosed by retinal biopsies include infectious retinitis and retinoblastoma. These entities are discussed separately in Chapters 8 and 9, respectively.

RETINOPATHY OF PREMATURITY

Previously called retrolental fibroplasias,[2] retinopathy of prematurity is a disease of the premature infant.[3] It is usually, but not always, associated with exposure to high concentration of oxygen.[4][5][6][7] The natural history and pathogensis of these diseases is discussed in detail elsewhere.[8][9][10][11] In brief, retinopathy of prematurity develops at the border of the developing retinal vasculature.[12][13] Presumably, ischemia leads to proliferation of the primitive microvasculature, which in turn may lead to tractional retinal detachment (Figure 7-1).[14][15]
Vitrectomies are preformed in the late stages to remove the vitreous and fibrovascular tissue in order to repair the retinal detachment.[16][17] When the retina is detached, the visual prognosis is poor.[18] In cytologic preparations, fibrous tissue, lens fragments (lensectomy), pigment-laden macrophages, and vitreous hemorrhage can be observed (Figure 7-2). These findings are not specific for retinopathy of prematurity.
References:
1. Green WR. Ophthalmology 1984;91:726-749.
2. Foos RY. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1975;195:87-100.
3. Keith CG, Kitchen WH. Med J Aust 1984;141:225-227.
4. Patz A. Am J Ophthalmol 1985;100:164-168.
5. Kushner BJ, Gloeckner E. Am J Ophthalmol 1984;27:148-163.
6. Shohat M, Reisner SH, Krikler R, Nissonkorn I, Yassur Y, et al. Pediatrics 1983;72:159-163.
7. Karlsberg RC, Green WR, Patz A. Arch Ophthalmol 1973:89:122-123.
8. Flynn JT, Bancalari E, Bachynski BN, Buckley EB, Bawd R, et al. Ophthalmology 1987;94:620-629.
9. Prendiville A, Schulenberg WE. Arch Dis Child 1988;63:522-527.
10. Silverman WA, Flynn JT. Boston: Blackwell Scientific, 1985.
11. McPherson AR, Hittner HM, Kretzer FL. Toronto: B.C. Decker, 1986.
12. Foos RY. Retina 1987;7:260-276.
13. Kushner BJ, Essner D, Cohen IJ, Flynn JT. Arch Ophthalmol 1977;95:29-38.
14. Campbell FW. Trans Ophthalmol Soc UK 1951;71:287-300.
15. Quinn GE, Schaffer DB, Johnson L. Am J Ophthalmol 1982;94:744-749.
16. Lightfoot D, Irvine AR. Am J Ophthalmol 1982;94:305-312.
17. Schepens CL. Am J Ophthalmol 1981;91:143-171.
18. Jabbour NM, Eller AE, Hirose T, Schepens CL, Liberfarb R, et al. Ophthalmology 1987;94:1640.

<previous> <next>