Pentocyl D Eye Drop is a combination of two medicines. It is used to enlarge (dilate) the pupil of the eye before an eye examination. It relaxes certain muscles in the eyes and may also relieve pain in certain eye conditions. Pentocyl D Eye Drop is for topical use only. It is generally administered 15-20 minutes prior to an eye examination. Do not self-administer this medicine at home. Check the label thoroughly for directions before using the medicine. The use of this medicine may cause temporary blurring of eyes, stinging sensation, or increased sensitivity to light in some people. However, these are temporary and usually resolve on their own. Let your doctor know if they do not go away or bother you. Do not use the medicine if you have a known allergy to any components of this preparation. Pentocyl D Eye Drop is contraindicated in people with primary glaucoma or a tendency toward glaucoma (e.g., narrow anterior chamber angle). Let your doctor know if you have any such conditions. It is not known whether this medicine is safe for pregnant and breastfeeding women. Let your doctor know if you are pregnant or breastfeeding to make sure it is safe for you and the developing baby.