Determining Factors for Fast Corneal Sensitivity Recovery After Pterygium Excision

Abstract

Purpose: To establish determining factors for fast corneal sensitivity (CS) recovery after pterygium excision.Methods: Thirty-two eyes of 14 males and 18 females with primary nasal pterygium were recruited. Differences in CS (in the four quadrants and the center using Cochet-Bonnet esthesiometer), pterygium corneal area (PCA), tear osmolarity, tear break up time, Schirmer test, and ocular symptoms were analyzed before and 1 month after lesion excision. The relationship between CS recovery (difference between the two time points; CS1-CS0) and the other features was assessed.Results: All the studied locations exhibited normal (6 cm) or near normal mean CS at the 2 time points, except tendency for moderate hypoesthesia in nasal CS0 (median 4.5; range: 1.5 -6.0 cm). Point by point comparison revealed significant postoperative improve in nasal location (p=0.008; Wilcoxon rang test) with normal values in 17 eyes (53%) and a median CS1= 5.0 cm (2.5 -5.5 cm) in 15 eyes with no complete recovery. No significant correlation was found between CS0 and the studied variables and CS1 was only significantly correlated with PCA (rho: -0.441; p<0.05). CS recovery also showed significant correlation with PCA (rho= -0.516; p<0.01). Conclusions:Corneal sensitivity recovery after pterygium excision showed important variability and the only studied factor that seems to be determinant could be PCA. It would be advisable to operate while lesion is relatively small, with lower surgical injury, and faster and complete recovery, thus protecting ocular surface homeostasis.3

Corneal Reinnervation and Sensitivity Recovery after Pterygium Excision

“…We found that the sensitivity of the nasal corneal quadrant in patients with pterygium dropped to about 42.61 ± 2.21 mm, while the rest of the corneas remained normal or only slightly altered, corroborating previous studies [15,16,32]. In two previous studies, decreased corneal sensitivity was related to altered structure in Bowman's membrane, where no nerve plexus could be detected using IVCM [24,25].…”

“…Partial or complete corneal anesthesia may indicate neural damage before clinically detectable lesions are observed [17]. Previous studies have shown that pterygium can also lead to partial anesthesia of affected corneas [16]. erefore, we evaluated both corneal sensitivity and subbasal nerve structures before and after pterygium excision.…”

“…In one study, patients with pterygium had lower Schirmer's test results and tear film stability [12], and tear film break-up times (TBUTs) have been found to increase significantly after primary pterygium excision [13,14]. Furthermore, hypoesthesia has been reported in the nasal corneas of patients with pterygium [15,16]. In this regard, corneal sensitivity is a measure of corneal nerve function and indicates the integrity of the protective mechanisms of the ocular surface.…”

“…Clinically, complete recovery is usually achieved by 1 month after pterygium excision [25]. Even though sensitivity is decreased in pterygium-affected corneas [15,16], no previous investigations have studied how corneal sensitivity is related to lesions in the corneal nerve fibers in patients with pterygium. Moreover, several studies have reported that corneal sensitivity recovers before reinnervation after corneal surgery [26,27].…”

Effects of ambient humidity on the Cochet–Bonnet aesthesiometer

“…Although the range of force exerted by COBO is extremely low (0.02-6 mN) [7], contact with the cornea by the filament tip commonly causes injury to the corneal epithelium during threshold measurements [8]. Despite this invasive design and other instrument limitations [9], the COBO continues to be considered the standard for corneal sensitivity assessment, as demonstrated in recent investigations involving ocular diseases [10][11][12], ocular surgery [13][14][15][16], and contact lens wear [17,18], arguably because of the instrument's ease of use and commercial availability.…”