To determine the efficacy, predictability and safety of long-term orthokeratology in children and adults. Case histories of 300 orthokeratology patients (596 eyes; 34.3% children; 65.7% adults) were reviewed to collect information on demographics, corneal and refractive parameters, visual acuity, residual refraction and adverse effects. Predictability was defined as the percentage of eyes with absolute values of spherical equivalent refraction ≤ 0.5 D of emmetropia, and efficacy as the ratio of post-orthokeratology uncorrected and pre-orthokeratology corrected distance visual acuity. Median duration of treatment was 37 and 28.5 months in children and adults, respectively (p = 0.022). During the first year, 17.2% of children and 33% of adults ceased lens wear (p < 0.001). For children and adults with a successful ortho-k treatment of at least one year of duration, 88.7% and 95.9% of eyes had a predictable refractive outcome, and efficacy was 0.98 and 1.01, respectively. A larger percentage of children (65.7%) were free of complications than of adults (55.4%) (p = 0.015). One event of microbial keratitis occurred in adults (6.8 cases per 10,000 patient-years) and none in children. Corneal staining was the most frequent complication, with a higher incidence in adults (p = 0.007) and in higher myopia (p < 0.001), higher anterior corneal eccentricity (p = 0.019) and smaller anterior horizontal radius (p = 0.027). Orthokeratology is a safe and predictable long-term procedure in children and adults, with a low incidence of serious adverse effects. Corneal staining episodes are relatively frequent throughout the course of the treatment, thus highlighting the relevance of education of experienced users.

Keratoconus is a progressive corneal disorder that can lead to irreversible visual impairment if not detected early. Despite its high prevalence, early diagnosis is often delayed, especially in low-to-middle-income countries due to limited awareness and restricted access to advanced diagnostic tools such as corneal topography, tomography, optical coherence tomography, and corneal biomechanical assessments. These technologies are essential for identifying early-stage keratoconus, yet their high cost limits accessibility in resource-limited settings. While cost and portability are important for accessibility, the sensitivity and specificity of diagnostic tools must be considered as primary metrics to ensure accurate and effective detection of early keratoconus. This review examines both traditional and advanced diagnostic techniques, including the use of machine learning and artificial intelligence, to enhance early diagnosis. Artificial intelligence-based approaches show significant potential for transforming keratoconus diagnosis by improving the accuracy and sensitivity of early diagnosis, especially when combined with imaging devices. Notable innovations include tools such as SmartKC, a smartphone-based machine-learning application, mobile corneal topography through the null-screen test, and the Smartphone-based Keratograph, providing affordable and portable solutions. Additionally, contrast sensitivity testing demonstrates potential for keratoconus detection, although a precise platform for routine clinical use has yet to be established. The review emphasizes the need for increased awareness among clinicians, particularly in underserved regions, and advocates for the development of accessible, low-cost diagnostic tools. Further research is needed to validate the effectiveness of these emerging technologies in detecting early keratoconus.

To analyse, describe and test diverse corneal and anterior segment parameters in normal and keratoconic eyes to better understand the geometry of the keratoconic cornea. 44 eyes from 44 keratoconic patients and 44 eyes from 44 healthy patients were included in the study. The Pentacam System was used for the analysis of the anterior segment parameters. New ad-hoc parameters were defined by measuring the distances on the Scheimpflug image at the horizontal diameter, with chamber depth now comprising of two distinctive distances: corneal sagittal depth and the distance from the endpoint of this segment to the anterior surface of the lens (DL). Statistically significant differences (p<0.05) between normal and keratoconic eyes were found in all of the analysed corneal parameters. Anterior chamber depth presented statistical differences between normal and keratoconic eyes (3.06±0.43mm versus 3.34±0.45mm, respectively; p=0.004). This difference was found to originate in an increase of the DL distance (0.40±0.33mm in normal eyes against 0.61±0.45mm in keratoconic eyes; p=0.014), rather than in the changes in corneal sagittal depth. These findings indicate that keratoconus results in central and peripheral corneal manifestations, as well as changes in the shape of the scleral limbus. The DL parameter was useful in describing the forward elongation and advance of the scleral tissue in keratoconic eyes. This finding may help in the monitoring of disease progression and contact lens design and fitting.

To explore anterior segment changes with keratoconus onset and progression to determine whether structural changes are predominantly corneal, limbal or both. To investigate these changes in different corneal meridians. Eighty-four eyes with keratoconus and 49 healthy eyes were included in the study. Eyes with keratoconus were divided in two groups according to the Amsler-Krumeich classification: stage I and stages II-IV. Scheimpflug images at three different meridians were used to evaluate the following parameters: anterior chamber depth from the endothelium (ACD_end) and corneal thickness (CT) (software provided), anterior chamber depth (ACD) and sagittal depth (SAGT) from the epithelium, and distance from the end point of SAGT to the anterior surface of the lens (DL) (measured manually), and [ACD - CT] and [SAGT - CT] (calculated). Changes in these parameters with ocular condition and meridian were analysed. Statistically significant larger values were found of ACD (p = 0.012) and DL (p = 0.016) with keratoconus onset and progression, with no differences in SAGT values. Besides, [ACD - CT] and [SAGT - CT] were significantly larger in keratoconus eyes (p < 0.001 and p = 0.003, respectively). Significant differences (all p < 0.001) were found in SAGT, [SAGT - CT] and DL among meridians. Changes in these parameters with keratoconus onset and progression were similar in all meridians. Considering the results from the three meridians under investigation, it may be concluded that keratoconus onset has an impact on the anterior segment as a whole and not only on corneal structures. The DL distance is a useful parameter to describe limbal changes in keratoconus.

To describe and compare corneal peripheral angles in normal and keratoconic eyes, to gain a better understanding of the topography of the periphery of the cornea in keratoconus and assist practitioners in the selection and fitting of large diameter contact lenses. Eighty-eight eyes were included in the study, divided into three groups: healthy (A0, 28 eyes), keratoconus at stage I according to the Amsler-Krumeich classification (AI, 33 eyes) and keratoconus at stages II to IV (AII, 27 eyes). The Pentacam Scheimpflug system was used to manually measure the corneal peripheral angles corresponding to a chord length range between 8.6 and 12.6 mm at 8 different peripheral locations. The peripheral angle was influenced by ocular condition and by the peripheral location, with no interaction effect between both factors. Statistically significant differences were found in mean corneal peripheral angles between groups A0 (30.84°±2.33°) and AI (31.63°±2.02°) (P=0.001) and between A0 and AII (31.37°±2.11°) (P=0.030). The differences between AI and AII were not significant. In all eyes, the largest and smallest peripheral angles were found at the temporal inferior and temporal superior locations, respectively, with a mean difference between largest and smallest of 3.37°±1.42° in healthy eyes and 2.96°±1.54° in keratoconus (AI+AII). Clinically insignificant differences were found in peripheral angles between keratoconus and healthy eyes, giving support to the use of large diameter, intralimbal contact lenses with peripheral designs, and resting on the same corneal region, as those fitted on normal corneas.

To assess the fitting process and clinical feasibility of a novel large diameter rigid gas-permeable (RGP) corneal contact lens (CL) presenting regular or reverse geometry for managing keratoconus (KC). The lens was designed to rest on the peripheral cornea and vault over the cone, aiming to enhance visual quality, comfort, and corneal physiology. 32 KC patients across all severity stages, including central, paracentral and peripheral cones enrolled. Lens parameters were customized from corneal measurements obtained via Oculus Pentacam HR tomography, mainly based on sagittal height and accounting for adequate tear film clearance. Visual acuity (VA), contrast sensitivity (CS), ocular complications, and user satisfaction were evaluated at baseline, and at one week and three months of lens wear. Twenty-four patients (41 eyes) were fitted and completed the 3-month follow-up (median age of 28.5 years, 9 females). A median of 2 trial lenses per eye (interquartile range of 4.5) were needed during the fitting process. Significant improvements in median VA (baseline: 0.32 logMAR; three months: 0.01 logMAR; p = 0.002) and CS (p < 0.001 at all frequencies) were observed compared to baseline values. Ocular complications remained below clinical significance, with superior limbic keratoconjunctivitis showing significant reduction over time (p < 0.001). Patient satisfaction was high, with a median daily lens wear of 9.5 h. Most users (79.2%) reported consistent comfort with their CLs. The novel large diameter RGP corneal CL demonstrated comparable efficacy to existing RGP CL designs, offering high levels of comfort and improved vision with minimal ocular complications.