Agreement Between Swept-source Optical Coherence Tomography and Rotating Scheimpflug Camera in Measurement of Corneal Parameters in Normal and Keratoconic Eyes.

Purpose: This study aimed to assess the agreement between topographic indices of healthy subjects and keratoconus (KCN) patients using a swept-source optical coherence tomography (SS-OCT CASIA2) versus a Scheimpflug camera (Pentacam). Methods: 40 eyes of 23 patients with KCN and 40 eyes of 20 healthy subjects were included and evaluated with the CASIA2, followed by the Pentacam. Two consecutive modalities were obtained for one eye of each patient. Corneal parameters, including anterior keratometry at steep (Ks) and flat meridians (Kf), anterior astigmatism, anterior and posterior corneal elevation values, thinnest corneal thickness, and apex corneal thickness, were evaluated. Results: CASIA2 and Pentacam showed perfect agreement (95% limits of agreement (LoA): -0.22 to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; P<0.01) for anterior (Ks) in normal and ectatic corneas, respectively. The cylinder amount had moderate agreement and correlation (95% LoA: -0.55 to 0.47D, ICC: 0.797, P<0.01) in normal, and moderate to strong agreement and correlation (95% LoA: -1.57 to 0.87D, ICC=0.911, P<0.01) in Keratoconic eyes. There was a fair agreement for anterior and posterior corneal elevation values in normal subjects (95% LoA: -3.09 to 4.59, 95% LoA: -6.91 to 7.31D). The thinnest corneal thickness amount had an excellent agreement in normal and KCN patients (ICC: 0.983, 0.953; respectively). Conclusion: Although the devices had different mean indices values, they had a good agreement based on the Bland-Altman plots. Since Pentacam is accepted as the standard tool for diagnosing ectatic cornea, pentacam CASIA2 is also helpful for early diagnosis of KCN.

Efficacy of five-flash intense pulsed light therapy technique in patients with meibomian gland dysfunction.

CLINICAL RELEVANCE: Meibomian gland dysfunction is the main cause of evaporative dry eye disease and can lead to ocular discomfort and ocular surface damage. Early diagnosis and management of this condition can prevent its impact on patients 'visual health and quality of life. BACKGROUND: In the last decade, intense pulsed light therapy (IPL) has been introduced as a therapeutic option for patients with meibomian gland dysfunction (MGD). Various treatment modalities and protocols have been reported to increase the efficacy of this technique. This study aimed to assess the efficacy of a novel five-flash IPL technique in combination with home-based therapy and to compare it with conventional home care alone in patients with MGD. METHODS: In a randomised controlled trial, 100 symptomatic MGD patients were enrolled. The treatment group underwent three sessions of a five-flash IPL therapy. For all participants, eyelid warming, lid hygiene and lubricant therapy was prescribed. Ocular surface parameters were compared for control and treatment groups. RESULTS: Ocular Surface Disease Index (OSDI), non-invasive keratograph tear break up time (NIKBUT), fluorescein TBUT, MG expressibility, meibum quality and tear osmolarity were improved at follow up visits in both groups (p < 0.05). On day 75, NIKBUT was significantly higher in the IPL group (p = 0.045). The IPL treatment effect was not statistically significant (p > 0.05), except for bulbar and limbal hyperaemia (p = 0.02 and p = 0.02). In both groups, younger patients showed more improvement in NIKBUT (p = 0.02, r = -0.32; p < 0.001, r = -0.52). CONCLUSION: IPL therapy combined with conventional home-based therapy, and home care alone are both effective for patients with MGD. IPL may have an additional role in the improvement of ocular hyperaemia.

Comparison of Keratoconus Cone Location of Different Topo/tomographical Parameters.

Purpose: To compare the corneal cone location on different maps and instruments, and their agreements, with elevation maps.Methods: In 90 left eyes with bilateral keratoconus, the apex of cone location was determined based on the maximum simulated keratometry (Kmax) location on the anterior sagittal curvature map by Pentacam HR, the maximum curvature on the mean curvature map by ATLAS 9000, most elevated point of the island of positive elevation relative to the best fit sphere on the front and back corneal elevation maps by Pentacam HR, and thinnest point on the thickness map by Pentacam HR and Orbscan, and the thinnest points on pachymetry and epithelial thickness maps by RTVue OCT.Results: There was a significant difference among the location on different maps along the x- and y-axes (p < .001). The lowest agreement with the cone apex on both front and back elevation maps was for the anterior sagittal curvature map and the highest agreement for the Pentacam thickness map. The majority of keratoconus cone apexes were displaced in the inferotemporal direction on the different maps except for the epithelial thickness maps.Conclusions: Despite the variability between different devices and methods; the thickness map on the Pentacam HR showed the highest correlation with the front and back elevation maps, while the RTVue epithelial thickness map showed the poorest correlation. Based on this study, epithelial thickness maps and anterior curvature maps should be utilized with caution to determine the location of the cone.

Global Prevalence of Meibomian Gland Dysfunction: A Systematic Review and Meta-Analysis.

Purpose: The purpose of this study is to assess the pooled prevalence of meibomian gland dysfunction (MGD) and evaluate its risk factors by gender, age, and ethnicity.Methods: Articles were searched reporting the prevalence of MGD from PubMed, Scopus, Web of Science, and Embase databases.Results: The estimated pooled prevalence of MGD was 0.358 (95% CI 0.26-0.46; I2: 99.57%). The prevalence of MGD was 0.358 (95% CI 0.24-0.50) in clinical and 0.359 (95% CI 0.22-0.52) in population-based studies. Men were more prone to MGD than women (OR: 1.24, 95% CI 1.01-1.52, p = 0.034). The rate of MGD was between 21.2% and 29.5% in Africans and Caucasians, to 71.0% in Arabs, and 67.5% in Hispanics.Conclusion: MGD is a quite prevalent disorder with an estimated pooled prevalence of 35.8%. Men are more prone to MGD than women. There is a large variation between studies in terms of quality, sample size, age ranges, diagnostic criteria, and ethnicity.