This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
A patient had seven irregular hyperpigmented macules on the trunk and multiple small hyperpigmented macules in the axillae and groins since early childhood. There were no other skin lesions. Which is the most likely investigation to support the diagnosis ? 
Select and explain. 
A. Slit lamp examination of eye, B. Measurement of intraocular tension, C. Examination of fundus, D. Retinal artery angiography
A: Slit lamp examination of eye
Answer: A: Slit lamp examination of eye 
Explanation: Seven hyper pigmented macules on trunk with multiple hyperpigmented macules in axilla (freckling) point towards the diagnosis of neurofibromatosis. So, for supporting the diagnosis we need to see iris hamartomas (lish nodules) by slit lamp examination.