What figure of speech is used in the fifth line?

Reading comprehension
Read the quoted parts carefully and answer the questions in English.Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:
Sometime too hot the eye of heaven shines
And often is his gold complexion dimmed;
……
But thy eternal summer shall not fade,
Nor lose possession of that fair thou ow'st;
（From Shakespeare's “Sonnet18”）

What figure of speech is used in the fifth line?
【正确答案】：

PERSONIFICATION.

【题目解析】：第五行使用的修辞格为拟人（personification），苍天明眸有时过于灼热，将“heaven shines”拟作灼热的明眸。