Comparison of the efficacy of lotrafilcon B and comfilcon A silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy

Background: At completion of transepithelial photorefractive keratectomy (t-PRK) surgery, the eye is usually fitted with a bandage contact lens to reduce discomfort and promote epithelial healing. This study aimed to compare the outcomes of eyes fitted with lotrafilcon B versus comfilcon A, silicone hydrogel bandage contact lenses after t-PRK for the correction of low to moderate myopia, with or without astigmatism. Methods: In this comparative, prospective study, patients with myopia < -6 D with or without astigmatism (< 1.75 D), who underwent t-PRK between January and June 2018, were randomly allocated to the lotrafilcon B and comfilcon A groups. Preoperative characteristics, including age, sex, eye treated, uncorrected visual acuity (UCVA), best-corrected visual acuity, mesopic pupil size, central corneal thickness, and refractive error were recorded. Postoperatively, pain score, UCVA, and corneal epithelial defect size on days 1, 4, and 7 were compared between the two groups. Results: Twenty-nine eyes were included in each group. Demographic characteristics and preoperative measurements were similar between the two groups. UCVA was significantly improved on day 7 as compared to day 1 in the comfilcon A group (P = 0.03), but remained the same in the lotrafilcon B group (P = 0.70) as on day 1 postoperatively. There was no significant difference in UCVA between the two groups at any follow-up visits (all P > 0.05). The pain score on the first postoperative day was significantly higher in the lotrafilcon B-fitted eyes than in the comfilcon A group (P < 0.001), but was significantly reduced in both groups compared to day 1 (both P < 0.001). The epithelial defect in the comfilcon A group was significantly greater than in the lotrafilcon B group (P < 0.001) at day 1 postoperatively, with significant improvement in both groups (both P < 0.001). Conclusions: Healing responses were better with lotrafilcon B than with comfilcon A bandage contact lenses. The patients had a greater mean pain score with lotrafilcon B than with comfilcon A lenses on the first postoperative day, yet the final outcome was comparable between the two groups. We did not encounter any postoperative complications related to contact lens wear

Descemet’s Stripping-Automated Endothelial Keratoplasty for Traumatic Aniridia and Aphakia

This Interventional case reports a challenging case of descemet’s stripping-automated endothelial keratoplasty (DSAEK) in a young male patient with traumatic aniridia, aphakia, and corneal edema. Surgery was planned in two stages; first was implantation of aniridia intraocular lens (AIOL), few months later, DSAEK procedure was performed. Successful outcome of both procedures was achieved as measured by the stability of the AIOL, clarity of the cornea, attachment of the lenticule, and improvement in vision. Aniridia implant supports a sufficient amount of air in the anterior chamber especially if the posterior segment is well formed, while providing the required lens power to improve vision. DSAEK procedure challenges that include iris defects and aphakia may be overcome by stepwise planning of the procedure

Protective Effects of Soluble Collagen during Ultraviolet-A Crosslinking on Enzyme-Mediated Corneal Ectatic Models.

Collagen crosslinking is a relatively new treatment for structural disorders of corneal ectasia, such as keratoconus. However, there is a lack of animal models of keratoconus, which has been an obstacle for carefully analyzing the mechanisms of crosslinking and evaluating new therapies. In this study, we treated rabbit eyes with collagenase and chondroitinase enzymes to generate ex vivo corneal ectatic models that simulate the structural disorder of keratoconus. The models were then used to evaluate the protective effect of soluble collagen in the UVA crosslinking system. After enzyme treatment, the eyes were exposed to riboflavin/UVA crosslinking with and without soluble type I collagen. Corneal morphology, collagen ultrastructure, and thermal stability were evaluated before and after crosslinking. Enzyme treatments resulted in corneal curvature changes, collagen ultrastructural damage, decreased swelling resistance and thermal stability, which are similar to what is observed in keratoconus eyes. UVA crosslinking restored swelling resistance and thermal stability, but ultrastructural damage were found in the crosslinked ectatic corneas. Adding soluble collagen during crosslinking provided ultrastructural protection and further enhanced the swelling resistance. Therefore, UVA crosslinking on the ectatic model mimicked typical clinical treatment for keratoconus, suggesting that this model replicates aspects of human keratoconus and could be used for investigating experimental therapies and treatments prior to translation

Fibril diameter, interfibrillar distance and density of spot of rabbit corneas before and after enzyme treatment and UVA crosslinking.

<p>Values denote mean ± standard deviation</p><p>*p<0.05 compared with the Control corneas</p><p>#p<0.05 compared with the COLG cornea</p><p>^p<0.05 compared with the Ch^aseABC corneas</p><p>Fibril diameter, interfibrillar distance and density of spot of rabbit corneas before and after enzyme treatment and UVA crosslinking.</p

Transmission electron microscope images of corneal ectatic model before and after crosslinking.

<p>Ultrastructure of control rabbit cornea under 9700x magnification. Column from left to right: Control cornea, COLG treated cornea, and Ch^aseABC treated cornea. Row from top to bottom: Non-CXL, CXL and CXL+ collagen</p

Schematic of enzyme-mediated corneal ectatic model and UVA crosslinking

<p>(A) Corneal ectatic model created by collagenase or chondroitinase treatments. (B) UVA crosslinking process with RF and soluble collagen.</p

Central Corneal Thickness (CCT) of rabbit corneas before and after enzyme treatment and UVA crosslinking.

<p>Values denote mean ± standard deviation</p><p>*p<0.05 compared with the Control corneas</p><p>#p<0.05 compared with the COLG corneas</p><p>^p<0.05 compared with the Ch^aseABC corneas</p><p>Central Corneal Thickness (CCT) of rabbit corneas before and after enzyme treatment and UVA crosslinking.</p