Megalopapilla

  • aka Megalodisc
  • Congenital anomalous enlarged optic disc area > 2.5 mm²
  • Not associated with other morphologic anormalities
  • High prevalence in natives of Marshall Islands
  • May be unilateral or bilateral
  • Large optic cup with central pallor given the axons more thinly spread over the disc surface
  • No treatment needed

Heidelberg OCT measurements

  • see reference 1 below

Nerve Areas

Parameter Mean SD Range
Disc area (mm²) 3.28 0.53 2.50-5.03
Cup area (mm²) 1.65 0.5 0.38-2.85
Rim area (mm²) 1.63 0.37 0.84-2.73
Cup/disc ratio area 0.70 0.86 0.35-0.85

Nerve fiber layer thickness

OCT measure Mean SD Range
Average thickness (μm) 102.51 12.68 58.41-120.25
Superior thickness (μm) 130.84 20.18 57.00-169.00
Nasal thickness (μm) 79.67 15.80 49.00-117.00
Inferior thickness (μm) 128.27 18.89 65.00-157.00
Temporal thickness (μm) 70.79 8.46 55.00-92.00

References

  1. Costa AMC et al. Optic Disc and Retinal Nerve Fiber Layer Thickness Descriptive Analysis in Megalopapilla. J Glaucoma 2014;26(6):368-371
  2. Brodsky CM. Congenital optic disk anomalies. Surv Ophthalmol 1994;39:89-112