Assessment of the Macula in Keratoconus: An Optical Coherence Tomography and Multifocal Electroretinography Study

Abstract

Purpose: The purpose of our study was to assess the macular thickness and the electrophysiological changes in keratoconic patients without any systemic or ocular disorders. Methods: 64 eyes of 32 keratoconus patients as well as 60 eyes of 30 controls participated in the study. All participants underwent a complete ophthalmological examination, including best-corrected visual acuity (BCVA) assessment, color vision testing, fundus examination, intraocular pressure measurement, central foveal thickness (CFT) measurement by optical coherence tomography (OCT) scan, and multifocal-electroretinogram (mf-ERG) recording. CFT, retinal response density (RRD) and P₁ latency were measured. Results: There was no statistically significant difference between the two groups concerning CFT and P₁ latency in mf-ERG. The RRD in mf-ERG differed significantly between keratoconus patients and controls. Of note, BCVA was positively associated with RRD in keratoconus patients. Conclusion: In some cases of keratoconus, a macular dysfunction not visible ophthalmoscopically may coexist and the low visual acuity could be due not only to the corneal abnormality, but also to the photoreceptor dysfunction. As a result, the preoperative electrophysiological study of patients with keratoconus is crucial to avoid a needless corneal transplantation.

Comparison of Macular Thickness in Patients with Keratoconus and Control Subjects Using the Cirrus HD-OCT

“…On average, no difference in macular thickness could be found when comparing the KC group and controls. This finding is in line with the findings of Moschos et al [ 13 ]. One KC subject had maculopathy which was easily detected and not masked although the patient had high refractive error (−24 D), prominent nerve fibres, Vogt's striae, and Fleisher's ring, indicating severe keratoconus or grade 3 according to the CLEK grading system [ 18 ]; see Figure 2 .…”

Assessment of the macula and choroid in pediatric keratoconus patients

“…In literature, there are some studies which present OCT measurements in patients with keratoconus 6, 7. Moschos et al presented central foveal thickness of 32 patients with keratoconus and they reported that a macular dysfunction which is not visible ophthalmoscopically may coexist in some cases and the low visual acuity could be due not only to the corneal abnormality, but also to the retinal dysfunction 6 .…”

“…In literature, there are some studies which present OCT measurements in patients with keratoconus 6, 7. Moschos et al presented central foveal thickness of 32 patients with keratoconus and they reported that a macular dysfunction which is not visible ophthalmoscopically may coexist in some cases and the low visual acuity could be due not only to the corneal abnormality, but also to the retinal dysfunction 6 . Cankaya et al presented optic disc and retinal nerve fiber layer (RNFL) measurements in 46 patients with keratoconus and they reported a significance difference of optic disc parameters in keratoconic patients compared to normal subjects 7 .…”

Diagnosis of keratoconus in a young male after the hint of electrophysiological test: A Case Report and Review of the Literature

“…There are several reports that KCN is accompanied by other diseases found by ERG or VEP. Moschos et al reported that the retinal response density in mf-ERG differed significantly between some KCN patients and controls, implying that impaired macular function might coexist in some KCN patients [31]. They also applied ERG and VEP in a series of 233 KCN patients and revealed the existence of a diffuse tapetoretinal degeneration or a macular lesion in many cases [32].…”