Bilateral Morphometric Alterations of Corneal Sub-basal Nerve Plexus in Patients Undergoing Unilateral Cataract Surgery.

Abstract

Purpose : There is increasing evidence of bilateral coordinated interaction between the nervous and the immune systems of both eyes in unilateral ocular diseases such as neurotrophic and herpetic keratitis. Since the nervous and immune interdependence between both eyes has not yet been investigated after surgery, our purpose was to evaluate bilateral morphometric changes of corneal sub-basal nerve plexus (SNP) occurring after unilateral cataract surgery by means of in vivo confocal microscopy (IVCM) images analyzed with an automated software.

Methods : IVCM was performed in the central cornea of 30 patients (20 M, 10 F; mean age 74.7±8.6 yrs) with cataract before (V0) and 1 month after surgery (V1) in either operated eyes (OEs) and unoperated eyes (UEs). The following IVCM parameters were calculated with ACCMetrics software: corneal nerve fibre density (CNFD); corneal nerve branch density (CNBD); corneal nerve fibre length (CNFL); corneal nerve total branch density (CTBD); corneal nerve fibre area (CNFA); corneal nerve fibre width (CNFW); corneal nerve fractal dimension (CNFrD). Dendritic cells (DCs) density was calculated using the internal software.

Results : The mean CNFD, CNBD, CNFL, CTBD, CNFA and CNFrD significantly decreased at V1 vs V0 in both eyes (respectively, 15.35±7.00 vs 21.21±6.56 n/mm² in OEs and 20.11±6.69 vs 23.20±7.26 in UEs; 13.57±12.16 vs 26.79±16.91 n/mm² in OEs and 24.28±14.88 vs 29.76±15.25 in UEs; 9.67±3.44 mm/mm² vs 13.49±3.42 in OEs and 12.53±3.60 vs 14.02±3.82 in UEs; 22.81±18.77 vs 42.25±24.64 n/mm² in OEs and 38.06±20.52 vs 43.93±22.27 in UEs; 0.0040±0.0021 vs 0.0058±0.0020 mm²/mm² in OEs and 0.0049±0.0016 vs 0.0057±0.0019 in UEs; 1.418±0.058 vs 1.470±0.037 in OEs and 1.466±0.040 vs 1.477±0.036 in UEs; all P<0.049). The other parameters did not change significantly from V0 to V1 (P>0.05).

Conclusions : Patients undergoing unilateral cataract surgery exhibited bilateral alterations of corneal SNP. This finding could explain the common observation that patients undergoing sequential cataract surgery often report a more unpleasant experience in their second operation. If confirmed in larger subsets, these results could provide useful indications for the choice of the proper timing in sequential cataract surgery.

This is a 2020 ARVO Annual Meeting abstract.

 

Representative IVCM images of corneal SNP in a patient before (A, B) and 1 month after cataract surgery (C, D) in the OE (A, C) and in the UE (B, D).