Central Corneal Thickness in Eyes With Optic Disc Drusen

Abstract

 

Purpose:

 

The etiology of optic nerve drusen (ODD) is not clearly understood. A leading hypothesis is that eyes with ODD have a small scleral canal. [1,2] A recent study found that in primary open angle glaucoma patients central corneal thickness (CCT) is inversely correlated to optic disc area. [3] The purpose of this study is to evaluate CCT in patients with ODD.

 

Methods:

 

Central corneal thickness was measured by means of ultrasound pachymetry in patients with a diagnosis of ODD (n=19 patients; 37 eyes) and a control population of healthy subjects (n=26 subjects, 50 eyes). All ODD were visible on clinical examination and/or by B-scan ultrasonography and none of the subjects involved in this study had history of ocular surgery. Measurements of CCT were compared by means and population distribution analysis.

 

Results:

 

When both eyes were eligible only the right eye of each individual was analyzed. Mean age was 65 ± 9 (ODD) and 51.0 ± 11 (controls) years. All subjects were white. The average refractive error was -2.01 ± 5 (ODD) and -0.55 ± 2 (Controls) diopters. A statistical difference was noted (p=0.034, independent sample t test) between the mean (± SD) CCT of both groups (Controls 556.23 ± 29.22 µm; ODD 581.32 ± 42.49 µm). A trend towards thicker corneas in the ODD group was found (p=0.016, chi-square test for trend). Distribution analysis of CCT measurements noted the largest cluster of ODD patients around 590 to 610 µm, whereas the largest cluster of control subjects was between 540 and 560 µm (Figure).Figure: Distribution analysis of central corneal thickness in µm between ODD eyes (dashed line) and control eyes (continuous line); 20-µm bin range.

 

Conclusions:

 

Optic disc drusen patients have thicker central corneal thickness measurements than controls. 1. Jonas et al Int Ophthalmol (1985); 2. Mullie et al. AJO (1985); 3. Pakravan BJO (2007).  

 

Keywords: neuro-ophthalmology: optic nerve