Abstract
Background: Keratoconus, a corneal ectasia, is associated with corneal thinning and altered optical media. Consequently, assessment of the visual field, optic nerve head and intraocular pressure measurements may be challenging in patients with keratoconus. Few studies have investigated posterior segment variables including the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thickness in patients with keratoconus.Aim: To investigate RNFL and GCC thickness in patients with keratoconus.Methods: A comparative quantitative research design was used. The sample consisted of 56 participants (28 with mild, moderate or severe keratoconus, and 28 controls) who accessed the optometry clinic at the University of KwaZulu-Natal. There was an equal distribution of male (n = 14) and female (n = 14) participants in the keratoconus and control groups. Most participants were black (n = 34) or Indian (n = 18). Corneal power and refractive error were assessed with the Oculus Keratograph and subjective refraction respectively. The iVue-100 optical coherence topography device was used to measure RNFL and GCC thickness. Data were analysed by descriptive and inferential statistics.Results: The mean global RNFL thickness was slightly higher in the control group than the keratoconus group for the right (106 µm vs. 99 µm) and left (103 µm vs. 98 µm) eyes but these differences were not significant (p ≥ 0.057). For all RNFL quadrants, slightly lower mean RNFL measurements were found in the keratoconus group. The mean GCC thicknesses were marginally higher (3 µm – 6 µm) in the control group.Conclusion: The RNFL and GCC thickness differences between patients with keratoconus and controls are not clinically significant. Therefore, abnormally reduced RNFL and GCC thickness measurements in patients with keratoconus warrant further investigation for other pathologies specifically glaucoma.
Highlights
Keratoconus is a bilateral asymmetrical non-inflammatory progressive corneal ectasia that affects one in every 2000 individuals in the general population.[1]
The study sample consisted of 56 participants, which included 28 each in the keratoconus and control groups
The results showed that both retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) measurements were comparable between the keratoconus and control groups
Summary
Keratoconus is a bilateral asymmetrical non-inflammatory progressive corneal ectasia that affects one in every 2000 individuals in the general population.[1] This ectasia is associated with a conical shaped cornea, apical protrusion and corneal thinning.[2] Assessment of the visual field may be challenging in patients with keratoconus owing to corneal opacities, high refractive errors and/or higher order aberrations.[3] Even though evaluation of optic disc photographs is a standard method to monitor optic nerve head changes in glaucoma suspects, this method may have limited usefulness in patients with keratoconus owing to poor-quality photographs and a relatively normal appearance of the optic nerve head.[4] patients with keratoconus usually present with myopia and low intraocular pressure (IOP) measurements.[4] Even in the absence of keratoconus, IOP measurements may be underestimated in individuals with thinner corneas.[1,5]. Keratoconus, a corneal ectasia, is associated with corneal thinning and altered optical media. Assessment of the visual field, optic nerve head and intraocular pressure measurements may be challenging in patients with keratoconus. Few studies have investigated posterior segment variables including the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thickness in patients with keratoconus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
