Retinal thickness and vascular density changes in Keratoconus: A systematic review and meta-analysis

Area of Science:

• Ophthalmology
• Retinal Imaging
• Corneal Diseases

Background:

• Keratoconus (KC) is a progressive corneal ectasia.
• Understanding associated retinal changes is crucial for a comprehensive view of the disease.
• Previous research has explored ocular structure variations in KC patients.

Purpose of the Study:

• To systematically review and meta-analyze changes in retinal layer thickness and vascular density in patients with keratoconus (KC).
• To quantify these alterations using data from observational studies.

Main Methods:

• A comprehensive literature search was performed across PubMed, Scopus, Embase, and Web of Science.
• Data from 16 observational studies (1932 eyes) were analyzed using a random effects model.
• Standardized mean differences (SMD) and weighted mean differences (WMD) were calculated for retinal parameters.

Main Results:

• Significant reductions were observed in retinal nerve fiber layer (RNFL) thickness, perifoveal macular thickness (nasal and superior regions), and superior capillary plexus (SCP) density in KC eyes.
• A significant increase in optic nerve head (ONH) disk area was also noted.
• No significant changes were found in foveal macular thickness, parafoveal macular thickness, or deep capillary plexus (DCP) density.

Conclusions:

• Keratoconus is associated with significant alterations in retinal structure and vascularity.
• These findings may not impact current treatment but are vital for future research on early detection and prognosis.
• Further investigation into the retina-corneal connection in KC is warranted.