ARTICLE IN PRESS JID: YMDA [mUS1Ga;June 27, 2020;8:1] Disease-a-Month xxx (xxxx) xxx Contents lists available at ScienceDirect Disease-a-Month journal homepage: www.elsevier.com/locate/disamonth Eyelid ptosis (Blepharoptosis) for the primary care practitioner Ema Avdagic, MD a , Paul O. Phelps, MD, FACS a,b,* a Department of Ophthalmology and Visual Science, University of Chicago, Chicago, IL, United States b Department of Surgery, Northshore University HealthSystem, 2050 Pfingsten Rd., Ste. 280, Glenview, Evanston, IL 60026, United States Introduction Eyelid ptosis (blepharoptosis or eyelid droop) is an eyelid disorder involving an abnormally low position of the upper eyelid. The normal upper eyelid position in adults is 0.5 to 2 mm below the superior portion of the cornea, and well above the center of the pupil which is nor- mally 5.5 mm below the superior edge of the cornea. 1, 2, 3 Drooping of the upper eyelid can involve either one or both eyelids, and it can occur from birth (congenital) or develop later in life (acquired). Since the cause of ptosis can vary in underlying etiology and treatment urgency, being well versed in this condition is important for the primary care physician. Ptosis can cause a mean- ingful decline in a patient’s activities of daily living. Reading and driving may be particularly af- fected. Downgaze (looking down) may exacerbate ptosis in patients who are minimally affected in primary gaze. 4 Furthermore, it represents a common cause of reversible peripheral vision loss. An abnormally low eyelid has also been shown to affect central vision and night vision due to a decreased amount of light reaching the macula. 5 Ptosis of the upper lid is diagnosed by observing an upper eyelid margin that is abnormally close to the central corneal light reflex. This is known as the margin to corneal light reflex dis- tance (MRD). 6–8 In cases of severe ptosis, the corneal light reflex may be completely obscured by the upper eyelid (Fig. 1A). In this case the MRD value would be zero. In case the patient reports a worsening of symptoms while reading, the clinician should also check the MRD in downgaze while the patient is attempting to read. 9 * Corresponding author at: Department of Surgery, NorthShore University HealthSystem, 2050 Pfingsten Rd., Ste. 280, Glenview, Evanston, IL 60026, United States. E-mail address: pphelps@northshore.org (P.O. Phelps). https://doi.org/10.1016/j.disamonth.2020.101040 0011-5029/© 2020 Elsevier Inc. All rights reserved. Please cite this article as: E. Avdagic and P.O. Phelps, Eyelid ptosis (Blepharoptosis) for the primary care practitioner, Disease-a-Month, https://doi.org/10.1016/j.disamonth.2020.101040