Pellucid marginal degeneration: Difference between revisions
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[[File:The_eye_&_I.jpg| | {{SI}} | ||
{{Infobox medical condition | |||
| name = Pellucid marginal degeneration | |||
| image = [[File:The_eye_&_I.jpg|250px]] | |||
| caption = Slit-lamp view of an eye with pellucid marginal degeneration | |||
| field = [[Ophthalmology]] | |||
| symptoms = [[Blurred vision]], [[astigmatism]], [[corneal thinning]] | |||
| complications = [[Corneal ectasia]], [[corneal hydrops]] | |||
| onset = Typically in [[adulthood]] | |||
| duration = [[Chronic condition|Chronic]] | |||
| causes = Unknown, possibly [[genetic]] | |||
| risks = Family history, [[connective tissue disorders]] | |||
| diagnosis = [[Slit-lamp examination]], [[corneal topography]] | |||
| differential = [[Keratoconus]], [[keratoglobus]] | |||
| treatment = [[Contact lenses]], [[corneal cross-linking]], [[corneal transplant]] | |||
| prognosis = Variable, can lead to significant [[visual impairment]] | |||
| frequency = Rare | |||
}} | |||
'''Pellucid marginal degeneration''' (PMD) is a rare, bilateral, non-inflammatory [[corneal]] thinning disorder characterized by a peripheral band of thinning, typically located in the inferior cornea. This condition leads to irregular [[astigmatism]] and can significantly affect [[visual acuity]]. | |||
==Presentation== | ==Presentation== | ||
Patients with PMD often present with progressive visual impairment due to the irregular astigmatism induced by the corneal thinning. Unlike [[keratoconus]], another corneal ectatic disorder, PMD does not typically present with [[corneal scarring]] or [[Vogt's striae]]. The hallmark of PMD is a clear, crescent-shaped band of thinning located 1-2 mm from the inferior limbus, with the area of maximum thinning being peripheral to the visual axis. | Patients with PMD often present with progressive visual impairment due to the irregular astigmatism induced by the corneal thinning. Unlike [[keratoconus]], another corneal ectatic disorder, PMD does not typically present with [[corneal scarring]] or [[Vogt's striae]]. The hallmark of PMD is a clear, crescent-shaped band of thinning located 1-2 mm from the inferior limbus, with the area of maximum thinning being peripheral to the visual axis. | ||
==Diagnosis== | ==Diagnosis== | ||
The diagnosis of PMD is primarily clinical, supported by imaging techniques such as [[corneal topography]] and [[corneal tomography]]. These imaging modalities reveal a characteristic "kissing doves" or "crab claw" pattern on the topographic map. [[Pachymetry]] can be used to measure the corneal thickness and confirm the peripheral thinning. | The diagnosis of PMD is primarily clinical, supported by imaging techniques such as [[corneal topography]] and [[corneal tomography]]. These imaging modalities reveal a characteristic "kissing doves" or "crab claw" pattern on the topographic map. [[Pachymetry]] can be used to measure the corneal thickness and confirm the peripheral thinning. | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
PMD must be differentiated from other corneal ectatic disorders, including [[keratoconus]], [[keratoglobus]], and [[Terrien's marginal degeneration]]. Unlike keratoconus, PMD does not typically present with central corneal thinning or apical protrusion. Keratoglobus involves generalized corneal thinning, and Terrien's marginal degeneration is associated with vascularization and lipid deposition. | PMD must be differentiated from other corneal ectatic disorders, including [[keratoconus]], [[keratoglobus]], and [[Terrien's marginal degeneration]]. Unlike keratoconus, PMD does not typically present with central corneal thinning or apical protrusion. Keratoglobus involves generalized corneal thinning, and Terrien's marginal degeneration is associated with vascularization and lipid deposition. | ||
==Management== | ==Management== | ||
Management of PMD focuses on correcting the irregular astigmatism to improve visual acuity. Options include: | Management of PMD focuses on correcting the irregular astigmatism to improve visual acuity. Options include: | ||
* '''Spectacles and Contact Lenses''': In the early stages, spectacles or rigid gas-permeable contact lenses may be sufficient to correct the astigmatism. | |||
* '''Surgical Interventions''': In advanced cases, surgical options such as [[intrastromal corneal ring segments]] (ICRS), [[corneal collagen cross-linking]] (CXL), or [[keratoplasty]] may be considered. [[Penetrating keratoplasty]] (PK) or [[deep anterior lamellar keratoplasty]] (DALK) can be performed in cases with significant corneal thinning and ectasia. | |||
* | |||
==Prognosis== | ==Prognosis== | ||
The prognosis for patients with PMD varies. With appropriate management, many patients can achieve satisfactory visual acuity. However, the progressive nature of the disease may necessitate ongoing adjustments in the management plan. | The prognosis for patients with PMD varies. With appropriate management, many patients can achieve satisfactory visual acuity. However, the progressive nature of the disease may necessitate ongoing adjustments in the management plan. | ||
==See Also== | ==See Also== | ||
* [[Keratoconus]] | * [[Keratoconus]] | ||
| Line 25: | Line 36: | ||
* [[Corneal collagen cross-linking]] | * [[Corneal collagen cross-linking]] | ||
* [[Penetrating keratoplasty]] | * [[Penetrating keratoplasty]] | ||
==References== | ==References== | ||
{{Reflist}} | {{Reflist}} | ||
==External Links== | ==External Links== | ||
{{Commons category|Pellucid marginal degeneration}} | {{Commons category|Pellucid marginal degeneration}} | ||
[[Category:Eye diseases]] | [[Category:Eye diseases]] | ||
[[Category:Disorders of sclera and cornea]] | [[Category:Disorders of sclera and cornea]] | ||
[[Category:Ophthalmology]] | [[Category:Ophthalmology]] | ||
{{Ophthalmology-stub}} | {{Ophthalmology-stub}} | ||
{{medicine-stub}} | {{medicine-stub}} | ||
Latest revision as of 12:51, 12 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Pellucid marginal degeneration | |
|---|---|
| |
| Synonyms | N/A |
| Pronounce | N/A |
| Specialty | N/A |
| Symptoms | Blurred vision, astigmatism, corneal thinning |
| Complications | Corneal ectasia, corneal hydrops |
| Onset | Typically in adulthood |
| Duration | Chronic |
| Types | N/A |
| Causes | Unknown, possibly genetic |
| Risks | Family history, connective tissue disorders |
| Diagnosis | Slit-lamp examination, corneal topography |
| Differential diagnosis | Keratoconus, keratoglobus |
| Prevention | N/A |
| Treatment | Contact lenses, corneal cross-linking, corneal transplant |
| Medication | N/A |
| Prognosis | Variable, can lead to significant visual impairment |
| Frequency | Rare |
| Deaths | N/A |
Pellucid marginal degeneration (PMD) is a rare, bilateral, non-inflammatory corneal thinning disorder characterized by a peripheral band of thinning, typically located in the inferior cornea. This condition leads to irregular astigmatism and can significantly affect visual acuity.
Presentation[edit]
Patients with PMD often present with progressive visual impairment due to the irregular astigmatism induced by the corneal thinning. Unlike keratoconus, another corneal ectatic disorder, PMD does not typically present with corneal scarring or Vogt's striae. The hallmark of PMD is a clear, crescent-shaped band of thinning located 1-2 mm from the inferior limbus, with the area of maximum thinning being peripheral to the visual axis.
Diagnosis[edit]
The diagnosis of PMD is primarily clinical, supported by imaging techniques such as corneal topography and corneal tomography. These imaging modalities reveal a characteristic "kissing doves" or "crab claw" pattern on the topographic map. Pachymetry can be used to measure the corneal thickness and confirm the peripheral thinning.
Differential Diagnosis[edit]
PMD must be differentiated from other corneal ectatic disorders, including keratoconus, keratoglobus, and Terrien's marginal degeneration. Unlike keratoconus, PMD does not typically present with central corneal thinning or apical protrusion. Keratoglobus involves generalized corneal thinning, and Terrien's marginal degeneration is associated with vascularization and lipid deposition.
Management[edit]
Management of PMD focuses on correcting the irregular astigmatism to improve visual acuity. Options include:
- Spectacles and Contact Lenses: In the early stages, spectacles or rigid gas-permeable contact lenses may be sufficient to correct the astigmatism.
- Surgical Interventions: In advanced cases, surgical options such as intrastromal corneal ring segments (ICRS), corneal collagen cross-linking (CXL), or keratoplasty may be considered. Penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty (DALK) can be performed in cases with significant corneal thinning and ectasia.
Prognosis[edit]
The prognosis for patients with PMD varies. With appropriate management, many patients can achieve satisfactory visual acuity. However, the progressive nature of the disease may necessitate ongoing adjustments in the management plan.
See Also[edit]
References[edit]
<references group="" responsive="1"></references>
External Links[edit]
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