Safety of collagen cross linking in advanced keratoconus in a patient with scleroderma

A 26-year-old female presented to us with complaints of progressive loss of vision in right eye (RE) since past 6 months. Patient was a known case of generalized systemic sclerosis with hypothyroidism for the past 2 years and was under treatment with a rheumatologist Physical features of scleroderma seen in her included diffuse skin tightness, hyper pigmentation of skin of face, abdomen, thighs, legs and arms, with ulcers on fingers. Her best corrected visual acuity was 20/320 in the RE and 20/20 in the left eye (LE). Slit lamp examination showed Fleischer's ring in the RE cornea, and prominent corneal nerves in the LE cornea. Pentacam evaluation revealed advanced keratoconus in RE and Forme Fruste keratoconus in LE. Corneal ectasia in systemic sclerosis is a rare event. Collagen cross linking procedure when undertaken in auto immune disorders may cause adverse reactions. We present a case of systemic sclerosis with advanced keratoconus, who underwent uneventful collagen crosslinking procedure, with stabilization of the cornea post operatively, seen at 6 months follow up. In this case report we emphasize on the factors which need to be taken into consideration when planning for surgical management like collagen cross linking in a collagen vascular disease such as scleroderma.

Corneal scarring following collagen cross-linking: evidence of increased lysyl oxidase activity

PURPOSE

To report a case of corneal scarring following collagen cross linking in a young female.

METHODS

A 24-year-old female presented to us with complaints of decreased vision and a white spot in her left eye following collagen cross linking (CXL) performed elsewhere, four years prior. We diagnosed her as a case of left eye leucomatous corneal opacity for which she underwent optical penetrating keratoplasty under local anaesthesia. The excised corneal tissue was evaluated by routine histopathology and immunohistochemistry.

RESULTS

At the final follow up visit, one year following corneal transplantation, her visual acuity improved to 20/20, J1 with a clear graft.

CONCLUSION

Vision threatening corneal scarring may be rarely noted following CXL.

A Prospective, Comparative, Clinical Study to Evaluate the Safety and Efficacy of Two Different 0.1% Riboflavin Solutions Used in Collagen Crosslinking Treatment for Patients with Keratoconus

Purpose

To compare the safety and efficacy of 0.1% riboflavin in two different solutions which is used in corneal collagen crosslinking (CXL) for the treatment of keratoconus.

Methods

This was a prospective, randomized, comparison study which included 100 eyes of 61 patients with progressive keratoconus who underwent CXL with riboflavin 0.1% solution as a photosensitizer, using the standard Dresden protocol of using 3mW/cm² UV-A irradiation for 30 minutes which corresponds to a total energy of 5.4 J/cm². The recruited patients were divided into 2 groups ie, Flavin Group and Peschke-D group by computer generated randomization. Postoperative examinations were conducted on 1 day, 1 month, 3 months, 6 months and 12 months after the crosslinking.

Results

For both groups, the mean manifest spherical equivalent (SE), astigmatism, best corrected distance visual acuity, keratometry values, thinnest pachymetry values, demarcation line depth and endothelial cell density preoperatively and at postoperative 12 months were comparable with no statistically significant differences. At 12 months postoperatively, 62% of eyes in the Flavin group, and 68% of eyes in the Peschke-D group had postoperative manifest SE of within ± 1.00 D. During UV-A exposure, the cornea in the Flavin group showed intraoperative thinning of 112 microns (27%) as compared with a thinning of 108.12 microns (26.5%) observed in the Peschke group (p=1.67) from the initial pachymetry readings. No eye in either group had any immediate or long-term postop vision threatening complications such as infectious keratitis, corneal melt, non-resolving corneal oedema or endothelial decompensation.

Conclusion

Both riboflavin solutions were equally safe and effective in the management of progressive keratoconus, and resulted in similar changes in terms of mean manifest spherical equivalent (SE), astigmatism, best corrected distance visual acuity, keratometry values, thinnest pachymetry values, demarcation line depth and endothelial cell density at the end of 12 months postoperatively.

Trial Registration Number

Ctri/2019/11/021841 (Www.ctri.nic.in).

Physioxia Stimulates Extracellular Matrix Deposition and Increases Mechanical Properties of Human Chondrocyte-Derived Tissue-Engineered Cartilage

Cartilage tissue has been recalcitrant to tissue engineering approaches. In this study, human chondrocytes were formed into self-assembled cartilage sheets, cultured in physiologic (5%) and atmospheric (20%) oxygen conditions and underwent biochemical, histological and biomechanical analysis at 1- and 2-months. The results indicated that sheets formed at physiological oxygen tension were thicker, contained greater amounts of glycosaminoglycans (GAGs) and type II collagen, and had greater compressive and tensile properties than those cultured in atmospheric oxygen. In all cases, cartilage sheets stained throughout for extracellular matrix components. Type II-IX-XI collagen heteropolymer formed in the neo-cartilage and fibrils were stabilized by trivalent pyridinoline cross-links. Collagen cross-links were not significantly affected by oxygen tension but increased with time in culture. Physiological oxygen tension and longer culture periods both served to increase extracellular matrix components. The foremost correlation was found between compressive stiffness and the GAG to collagen ratio.