In order to better acknowledge the ocular fundus picture in premature infants and to determine the incidence and clinical course of retinopathy of prematurity (ROP), from October 1987 to April 1989, 187 cases with a gestational age of less than 38 weeks or a birth weight of less than 2,500 g were enrolled for examination and follow-up study with indirect ophthalmoscope. One hundred and fifty cases (80.21%) were free from ROP bilaterally. Thirty-seven cases (19.79%) had ROP. Except for one case that showed unilateral regressed ROP, all were bilaterally affected. The mean birth weight and gestational age in the nonROP group were 1,824 +/- 426 g and 33.6 +/- 2.9 weeks, respectively, and in the ROP group were 1,395 +/- 490 g and 30.7 +/- 3.9 weeks, respectively. The difference for both factors between the two groups were statistically significant (p less than 0.05). Several specific fundus features were noticed in a high percentage of the nonROP group, these included a small cup to disc (C/D) ratio, pigmented ring around the disc, hypopigmented fundus and a greenish-gray color in the peripheral vascularized retina. In addition, 8.2% of this group had persistent primary vitreous remnant, and 5.6% had retinal hemorrhage. The macular development was subdivided into three stages. In both the ROP and nonROP groups, the difference of gestational age at each advancing stage was statistically significant by the Student t-test. No delay in macular development was noticed in the ROP group.(ABSTRACT TRUNCATED AT 250 WORDS)