Repeat corneal collagen cross-linking after failure of primary cross-linking in keratoconus.

BACKGROUND: Primary corneal collagen cross-linking (CXL) stabilises 96% of progressive keratoconus. There is limited evidence for the treatment of choice when this fails. We present 10 years of repeat CXL and compare with our published experience of primary CXL to (1) identify perioperative risk factors of primary CXL failure and (2) demonstrate the safety and efficacy of repeat CXL. METHODS: Patients undergoing repeat accelerated epithelium-off CXL at St James's University Hospital, Leeds, UK January 2012-August 2022 were identified through electronic patient record, and compared with a previously published cohort of primary CXL patients at the same site. RESULTS: Twenty-one eyes underwent repeat CXL. The mean interval between primary and repeat CXL treatments was 47.1 months (SD 22.5). Twenty (95%) eyes stabilised after repeat CXL at a mean follow-up of 29.9 months. These cases were compared with 151 cases of primary CXL from our previous study. Patients failing primary CXL were significantly younger (21.3 years (SD 7.0) vs 26.7 years (SD 6.5), p=0.0008). Repeat CXL and primary CXL induced a similar amount of flattening of Kmax (-1.2 D (SD 3.9) vs -0.7 D (SD 4.4), p=0.22). A small, but clinically insignificant, improvement in best-corrected visual acuity was found in the repeat CXL group (-0.04 (SD 0.17) vs -0.05 (SD 0.13), p=0.04). No complications of repeat CXL were noted. CONCLUSION: Younger age may be associated with failure of primary CXL. Repeat CXL is an effective and safe treatment for progressive keratoconus despite primary CXL.

Bilateral, Unaugmented, Loop Myopexy Performed for a Severe Case of Heavy Eye Syndrome.

AIM: To report the clinical features and surgical outcomes of one patient with heavy eye syndrome who underwent bilateral, unaugmented, full loop myopexy. METHODS: A 47-year-old lady with high myopia, high axial length, progressive esotropia, slippage of the lateral rectus (LR) inferiorly and superior rectus (SR) medially on magnetic resonance imaging (MRI) was diagnosed with heavy eye syndrome. Unaugmented loop myopexy without medial rectus (MR) recession was offered. RESULTS: On follow-up at 30 months, a small residual esotropia of 6 prism diopters (PD) at near and 10 PD at distance was achieved. Both abduction and elevation were improved in both eyes. CONCLUSIONS: The high angle of esodeviation can be challenging to correct adequately with surgery, with many options available: resection-recession, hemitranspositions (Yamada's procedure), partial loop myopexy (modified Jensen's procedure) and full loop myopexy (Yokoyama's procedure). It remains unclear which procedure is optimal for severe disease. In this case, we present bilateral, unaugmented, full loop myopexy as our preferred choice for high esotropia.

Transcranial direct current stimulation of the motor cortex in the treatment of chronic nonspecific low back pain: a randomized, double-blind exploratory study.

OBJECTIVES: To test the proof of principle that active anodal transcranial direct current stimulation (tDCS) applied to the motor cortex reduces pain significantly more than sham stimulation in a group of participants with chronic nonspecific low back pain. METHODS: The study utilized a within-participants sham-controlled, interrupted time series design. A sample of 8 participants was recruited. After 3 days of baseline measures, patients entered a 15-day experimental period (Mondays to Fridays) for 3 consecutive weeks. During this period each patient received sham stimulation daily until a randomly allocated day when active stimulation was commenced. Active stimulation was then given daily for the remaining days of the experimental period. Both the participants and the assessors were blinded. The primary outcomes were average pain intensity and unpleasantness in the last 24 hours measured using a visual analogue scale. Secondary outcomes included self-reported disability, depression and anxiety, a battery of cognitive tests to monitor for unwanted effects of stimulation, and patients' perceptions of whether they had received active or sham stimulation. Data were analyzed using generalized estimating equations. RESULTS: No significant effect was seen in the primary outcomes between active and sham stimulation (average pain intensity P = 0.821, unpleasantness P = 0.937) or across any other clinical variables. There was evidence that patients may have been able to distinguish between the active and sham conditions (P = 0.035). DISCUSSION: These results do not provide evidence that tDCS is effective in the treatment of chronic back pain. The use of a small convenience sample limits the generalizability of these findings and precludes definitive conclusions on the efficacy of tDCS in chronic nonspecific low back pain.