Two hundred nine macular holes of both pathologic myopia and idiopathic senile type were statistically analyzed to find out which factors cause retinal detachment in eyes with macular holes. The incidences of retinal detachment were as follows: 97.6% in myopia over -8.25 D, 67.7% in myopia between -8.0 and -3.25 D, and 1.1% in eyes under -3.0 D; 100% in widespread chorioretinal atrophy, 90.6% in spotty or lineal chorioretinal atrophy, 64.3% in myopic tigroid fundus, and 0% in eyes without myopic tigroid or atrophy; 96.0% in eyes with posterior staphyloma and 8.2% in eyes without it; 56.4% in posterior vitreous detachment [PVD] (+) eyes, 53.3% in PVD(+/-) eyes, and 51.9% in PVD(-) eyes. The statistically significant (P less than 0.05) factors that caused retinal detachment were refractive error, myopic chorioretinal change, and posterior staphyloma. There was no statistically significant difference regarding PVD.