The Effects of Topical Coenzyme Q₁₀ and Vitamin E <smlcap>d</smlcap>-α-Tocopheryl Polyethylene Glycol 1000 Succinate after Cataract Surgery: A Clinical and in vivo Confocal Study

Abstract

Purpose: To evaluate the postoperative effects of topical coenzyme Q₁₀ + vitamin E <smlcap>d</smlcap>-α-tocopheryl polyethylene glycol 1000 succinate (CoQ₁₀) aftercataract surgery. Methods: 40 consecutive patients were randomized to receive CoQ₁₀ or saline solution (SS) twice daily for 9 months after uneventful cataract surgery with a temporal port. Before surgery, on day 14 and at months 3, 6 and 9, they underwent non-invasive break-up time (NIBUT) testing, Schirmer test, BUT, aesthesiometry as well as in vivo confocal microscopy of the subbasal nerve plexus of the cornea (SBP). The density of the subbasal nerves was calculated in the central (CFD) and temporal (TFD) cornea (number of fibres per field). Results: On day 14, surgery reduced CFD and TFD, respectively, by 25–35 and 50%; indices of ocular surface stability were all impaired. The treatment with CoQ₁₀ was associated with faster nerve regeneration than SS (at month 3, CFD +1.5 ± 1.9 vs. +0.2 ± 1.8, p = 0.04, and TFD +2.5 ± 1.7 vs. +1.0 ± 1.6, p = 0.007; at month 6, TFD +2.7 ± 1.9 vs. +1.4 ± 1.5, p = 0.02) and better stability of ocular surface (NIBUT and BUT) throughout the study. No relevant side effects were found, apart from occasional burning in 10% of CoQ₁₀ patients. Conclusions: Changes of the corneal nerves occurring after cataract surgery may influence the integrity of the ocular surface. Treatment with topical CoQ₁₀ has a positive effect in restoring SBP anatomy and ocular surface stability.

Corneal Involvement in Uneventful Cataract Surgery: An in vivo Confocal Microscopy Study

“…Darwish et al [6] investigated nerve regeneration after penetrating keratoplasty and suggested that - in the apparent absence of subbasal nerves - the postoperative recovery of central corneal sensitivity could be explained by the presence of epithelial nerves and/or by thinner subbasal nerve fibers that could not be detected by IVCM. In our dataset, corneal sensitivity did not correlate with nerve fiber number, thus confirming our previous findings [8]. This may be explained according to three hypotheses: (1) the presence of regenerated epithelial nerves and/or thin subbasal nerve fibers that could not be detected by IVCM (as in the case of corneal transplants); (2) the lack of correlation between corneal sensitivity and density of subbasal plexus nerve fibers, as reported by Patel et al [29] in normal corneas; and (3) the vicarious role of nerve fibers of the other, unaffected corneal quadrants.…”

“…diabetes) for neuropathy. Such findings are similar to those of our previous study, in which a 2.7-mm temporal port was chosen [8]. …”

“…Fiber regeneration was still incomplete 3 months after surgery, thus confirming the findings of a previous paper by our group [8]. Compared with month 1, the number of fibers had doubled, and beading and reflectivity had improved, although all three parameters remained significantly different compared with baseline.…”

“…At months 1 and 3, the decreased number of fibers was accompanied by changes in appearance of the fibers, with increased beading and reticular appearance, a fact that has been correlated with increased axoplasmic flow in the course of regeneration [28]. A previous case report on corneal IVCM after cataract surgery showed regeneration of the subbasal nerve plexus 4 months after phacoemulsification [7], and our report on 40 patients highlighted the fact that nerve density is similar to that at baseline 6 months after surgery [8]. Darwish et al [6] investigated nerve regeneration after penetrating keratoplasty and suggested that - in the apparent absence of subbasal nerves - the postoperative recovery of central corneal sensitivity could be explained by the presence of epithelial nerves and/or by thinner subbasal nerve fibers that could not be detected by IVCM.…”

“…In vivo confocal microscopy (IVCM) allows the study of corneal structures, including the subbasal nerve plexus [1], at a cellular level, which would not be possible with any other clinical instrument. There are studies showing subbasal nerve plexus changes after refractive surgery [4,5] and penetrating keratoplasty [6], but - to the best of our knowledge - changes after cataract surgery were described only in a case report [7] and in a recent paper by our group [8]. A significant reduction in corneal sensitivity after phacoemulsification was also shown within 3 months from surgery [9].…”