Pellucid Marginal Degeneration Follow-up
- Author: Karim Rasheed, MD, MSc; Chief Editor: Hampton Roy, Sr, MD more...
Further Outpatient Care
Patients should receive follow-up care as needed.
Corneal hydrops similar to that seen in keratoconus, with disruption of the endothelial basement membrane and hydration of the adjacent corneal stroma, rarely occurs in pellucid marginal degeneration (PMD).
Keratoglobus causes generalized thinning of the cornea.
- The thinning is most marked at the limbus, extending circumferentially for 360°.
- The whole cornea protrudes, in contrast to the regional thinning seen in keratoconus and the inferior paralimbal thinning in pellucid marginal degeneration.
Terrien marginal degeneration affects an age group similar to that affected by pellucid marginal degeneration.
- Terrien marginal degeneration can be bilateral.
- Although this condition can be associated with large amounts of astigmatism, it can be differentiated from pellucid marginal degeneration because the superior cornea is predominantly affected and because the area of thinning is often associated with vascularization and lipid deposition.
Furrow degeneration has some features of pellucid marginal degeneration.
- An intact epithelium is present, and the area of corneal thinning is not vascularized, at least in the acute phase.
- The differentiating feature is that the area of thinning is closer to the limbus with virtually no intervening zone of normal cornea, unlike the findings in pellucid marginal degeneration.
- Furrow degeneration occasionally involves the superior cornea, and an associated adjacent area of scleritis may be present.
- Edges of the furrow are steeper than the gradual attenuation seen in pellucid marginal degeneration.
- Furrow degeneration occurs adjacent to the lipid deposition in arcus senilis, which is typically observed in elderly patients.
Peripheral corneal melting disorders, such as Mooren ulcer, or peripheral melting secondary to rheumatologic disorders are characterized by pain.
- This pain may be severe in cases of Mooren ulcer.
- Associated findings include an epithelial defect over the area of thinning and corneal vascularization adjacent to the area of thinning in the acute phase.
Contact lens-induced warping of the cornea can mimic the appearance of pellucid marginal degeneration on corneal topography.
No large-scale longitudinal studies of pellucid marginal degeneration have been reported.
- Quantifying the proportion of patients who eventually require surgery is difficult.
- Contact lens fitting and surgical correction are more difficult with pellucid marginal degeneration than with keratoconus.
In a follow-up of their ongoing longitudinal study of keratoconus, Rabinowitz and Rasheed have observed 31 patients with pellucid marginal degeneration up to 8 years.
- Five patients have required corneal transplantation in 1 eye, and one patient has required transplantation in both eyes.
- The data must be interpreted with caution because these observations may have been affected by selection bias.
Oie Y, Maeda N, Kosaki R, Suzaki A, Hirohara Y, Mihashi T, et al. Characteristics of ocular higher-order aberrations in patients with pellucid marginal corneal degeneration. J Cataract Refract Surg. 2008 Nov. 34(11):1928-34. [Medline].
Ertan A, Bahadir M. J. Intrastromal ring segment insertion using a femtosecondlaser to correct pellucid marginal corneal degeneration. J Cataract Refract Surg. 2006 Oct. 32(10):1710-6. [Medline].
Ghajarnia M, Moshirfar M, Mifflin MD. Descemet detachment after femtosecond-laser-assisted placement of intrastromal ring segments in pellucid marginal degeneration. J Cataract Refract Surg. 2008 Dec. 34(12):2174-6. [Medline].
Rasheed K, Rabinowitz YS. Results of combined lamellar and penetrating keratoplasty for pellucid marginal degeneration [abstr]. Ophthalmol Suppl. 1997. Oct:191.
Javadi MA, Karimian F, Hosseinzadeh A, Noroozizadeh HM, Sa'eedifar MR, Rabie HM, et al. Lamellar crescentic resection for pellucid marginal corneal degeneration. J Refract Surg. 2004 Mar-Apr. 20(2):162-5. [Medline].
Krachmer JH. Pellucid marginal corneal degeneration. Arch Ophthalmol. 1978 Jul. 96(7):1217-21. [Medline].
Kymionis GD, Aslanides IM, Siganos CS, Pallikaris IG. Intacs for early pellucid marginal degeneration. J Cataract Refract Surg. 2004 Jan. 30(1):230-3. [Medline].
Maccheron LJ, Daya SM. Wedge resection and lamellar dissection for pellucid marginal degeneration. Cornea. 2012 Jun. 31(6):708-15. [Medline].
Maguire LJ, Klyce SD, McDonald MB, Kaufman HE. Corneal topography of pellucid marginal degeneration. Ophthalmology. 1987 May. 94(5):519-24. [Medline].
Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998 Jan-Feb. 42(4):297-319. [Medline].
Schanzlin DJ, Sarno EM, Robin JB. Crescentic lamellar keratoplasty for pellucid marginal degeneration. Am J Ophthalmol. 1983 Aug. 96(2):253-4. [Medline].