H49.42 Progressive external ophthalmoplegia, left eye

Billable ICD-10-CM code, FY2026.

Applies from H49 Paralytic strabismus

Excludes2 (not included here)

• internal ophthalmoplegia (H52.51-)
• internuclear ophthalmoplegia (H51.2-)
• progressive supranuclear ophthalmoplegia (G23.1)

Applies from H49.4 Progressive external ophthalmoplegia

Excludes1 (never code together)

• Kearns-Sayre syndrome (H49.81-)

MS-DRG index

Defines the logic of DRG(s) 123 in MDC 02.

Approximate ICD-9-CM (GEMs)

• 378.55 External ophthalmoplegia (approximate)

Nearby codes

• H49.32 Total (external) ophthalmoplegia, left eye
• H49.33 Total (external) ophthalmoplegia, bilateral
• H49.4 Progressive external ophthalmoplegia
• H49.40 Progressive external ophthalmoplegia, unspecified eye
• H49.41 Progressive external ophthalmoplegia, right eye
• H49.42 Progressive external ophthalmoplegia, left eye (this code)
• H49.43 Progressive external ophthalmoplegia, bilateral
• H49.8 Other paralytic strabismus
• H49.81 Kearns-Sayre syndrome
• H49.811 Kearns-Sayre syndrome, right eye
• H49.812 Kearns-Sayre syndrome, left eye