Pellucid corneal marginal degeneration: A review

Area of Science:

• Ophthalmology
• Corneal Diseases
• Ocular Surface Disorders

Background:

• Pellucid marginal corneal degeneration (PMD) is a rare, progressive ectatic disorder.
• It characteristically affects the inferior peripheral cornea in a crescentic pattern.
• The exact prevalence and etiology of PMD remain largely unknown.

Purpose of the Study:

• To review the clinical features, differential diagnosis, and management strategies for PMD.
• To highlight the importance of corneal topography in early detection.
• To inform clinicians about PMD's distinct characteristics to prevent misdiagnosis, especially with keratoconus.

Main Methods:

• Literature review of clinical features, diagnostic methods, and treatment options for PMD.
• Analysis of diagnostic challenges, including differentiation from keratoconus.
• Synthesis of current management approaches, from conservative to surgical.

Main Results:

• PMD typically affects males between the 2nd and 5th decades, regardless of ethnicity.
• Symptoms range from reduced visual acuity and irregular astigmatism to rare cases of sudden vision loss.
• Early PMD may be missed without corneal topography, while advanced stages can be misdiagnosed as keratoconus.

Conclusions:

• Accurate diagnosis of PMD relies on recognizing its unique topographical and slit-lamp features.
• Spectacles and contact lenses are primary management tools, with surgery for visual rehabilitation.
• Awareness of PMD is vital for clinicians, particularly before considering refractive surgery.