ICD10 Code = H57.03
Genomic coordinate (human 13:94,400,001 MCOR).
Cytoband (human 13q32.1 MCOR).
OMIM’ genes @ 13q32.1 = 28 genes.
ClinVar = 1 MCOR variants reported.
PANTHER Classification is PTHR25232
Here I present: “Congenital Microcoria-miosis”, Victor McKusick, Mendelian Inheritance in Man’, 1966.
INTRODUCTION.
Inherited congenital microcoria, also referred to as congenital miosis, is characterized by bilateral small pupils (diameter less than 2 mm) that result from an underdevelopment of the dilator pupillae muscle of the iris. Iris transillumination defects are a constant feature. The pupil dilates poorly or not at all in response to topically administered mydriatic drugs. The disorder is transmitted as an autosomal dominant trait with complete penetrance and is associated with goniodysgenesis and glaucoma.
MIOSIS & MYDRIASIS.
Miosis refers to the constriction of the pupil, which occurs in bright light when the circular sphincter muscles contract. Mydriasis refers to the dilation of the pupil, which occurs in dim light when the radial dilator muscles contract.
Since these terms describe how the eye naturally adjusts to light, a variety of everyday factors, medical conditions, or substances can cause them:
Common Causes of Miosis (Constricted Pupils)
Bright environments: Exposure to high levels of light, such as direct sunlight or bright indoor fixtures.
Medications and substances: Opioids (such as morphine or codeine), certain blood pressure medications (like clonidine), or eye drops used to treat glaucoma (like pilocarpine).
Medical conditions: Horner’s syndrome, inflammation inside the eye (uveitis), or certain types of strokes that affect the brainstem.
Common Causes of Mydriasis (Dilated Pupils)
Low-light environments: Dimly lit rooms, nighttime settings, or darkness where the eye needs to let in more light.
Medications and substances: Anticholinergic drugs (like atropine), stimulants (such as amphetamines or cocaine), certain antidepressants, or dilating eye drops used during eye exams.
Psychological factors or trauma: Strong emotional responses (like fear or excitement), a surge of adrenaline, or physical head injuries/trauma to the eye.
