Corneal Tomography Research Articles

Differentiation Between Pellucid-Like Keratoconus and Pellucid Marginal Degeneration Using Swept-Source Optical Coherence Tomography

Purpose: The distinction between pellucid-like keratoconus (PLK) and pellucid marginal corneal degeneration (PMD) based on tomographic examinations is difficult. In this study, corneal tomographic and biomechanical parameters, after classifying PMD and PLK using swept-source optical coherence tomography, were analyzed. Methods: Diagnoses of PLK and PMD were made using SS-OCT imaging, two groups were formed: PLK (n = 30) and PMD (n = 10). Corneal thickness was measured at the 5, 6, and 7 o'clock positions centrally, superiorly, and inferiorly with SS-OCT. Tomographic, densitometric, and biomechanical parameters were investigated using Scheimpflug-based methods. Results: Patients with PMD were significantly older than patients with PLK (55.2 [95% CI, 47.0–63.3] vs. 42.0 years [95% CI, 38.2–46.0]; P = 0.002). The median Kmax value did not differ significantly between PMD and PLK (54.7 D [95% CI, 48.0–62.8] vs. 52.0 D [95% CI, 49.4–53.9]; P = 0.5). Astigmatism was significantly higher in the PMD group than in the PLK group (median 9.0 D [6.1–11.5] D vs. 3.7 [2.4–4.6] D; P < 0.001). The biomechanical parameters did not differ between PMD and PLK (DA Ratio max 2 mm, integrated radius, stiffness parameter at first applanation, and Corvis Biomechanical Index (CBI); each P > 0.05). There were significant differences in the corneal thickness ratio inferior to the center between the two groups (−23.7% [−31.5 to (−15.9)] versus 2.4% [−1.2 to 5.9], P < 0.001) and at 6 o'clock (−29% [−38.7 to −19.29] versus 0.18% [−4.62 to 5, P < 0.001) and 7 o'clock (−24.5% [−34.2 to −14.7] versus −2.0% [−6.65 to 2.73], P < 0.001). Conclusions: Neither Scheimpflug-based tomographic nor biomechanical parameters can differentiate between PLK and PMD. SS-OCT can help with this differentiation because of the typical thinning of corneal pachymetry near the limbus.

Data augmentation via warping transforms for modeling natural variability in the corneal endothelium enhances semi-supervised segmentation.

Image segmentation of the corneal endothelium with deep convolutional neural networks (CNN) is challenging due to the scarcity of expert-annotated data. This work proposes a data augmentation technique via warping to enhance the performance of semi-supervised training of CNNs for accurate segmentation. We use a unique augmentation process for images and masks involving keypoint extraction, Delaunay triangulation, local affine transformations, and mask refinement. This approach accurately captures the natural variability of the corneal endothelium, enriching the dataset with realistic and diverse images. The proposed method achieved an increase in the mean intersection over union (mIoU) and Dice coefficient (DC) metrics of 17.2% and 4.8% respectively, for the segmentation task in corneal endothelial images on multiple CNN architectures. Our data augmentation strategy successfully models the natural variability in corneal endothelial images, thereby enhancing the performance and generalization capabilities of semi-supervised CNNs in medical image cell segmentation tasks.

Comparison of corneal indices between normal and keratoconus (kc) using pentacam hr for patients aged 6-21 years

OBJECTIVES: The aim is to compare normal and KC corneas using Pentacam keratometry, curvature indices, elevation indices, and pachymetry indices for patients aged between 6 to 21 years in the Riyadh area and analyze the indicators' sensitivity and specificity in differentiating between normal and KC corneas. METHOD: The present study employed a prospective, cross-sectional, observational, multicenter design to gather data from patients aged 6 to 21 who were seen in several non-ophthalmic emergency departments in Riyadh, Kingdom of Saudi Arabia, in 2017. Scheimpflug corneal tomography system in rotation was used to measure the cornea. Following optometric exams, corneal imaging and KC index measurements were performed using the Pentacam. RESULTS: Between the normal and KC groups, the majority of variables showed noteworthy statistical differences (p < 0.001). The most effective indicators for keratoconus discrimination were K Max, ISV, and IHD. K Max, ISV, and IHD each had an area under the curve of 0.94, 0.90, and 0.93. IHA, IHD, and in the paired study of the ROC curves, CKI indices performed significantly better than the other topometric variables. (p < 0.05). Nevertheless, when comparing the ROC curves with ISV, IVA, and KI pairwise, there are no statistically significant variations. Furthermore, the area under the curve (AUC) of the ROC for display TP in the pairwise comparison was smaller than that of Pachy apex (p 0.002). PPI max, ART average, and TP all had larger areas under the curves than TP (p<0.05) CONCLUSION: Pentacam indices are vital to the diagnosis of KC. K Max, ISV, and IHD are the best diagnostic indices for KC. Yet, using a combination of indices is advised to improve the diagnosis and accuracy of Pentacam indices to differentiate KC from normal.

Distribution of Belin-Ambrosio indices using Pentacam HR for normal patients aged 6 to 21 years in the Riyadh area

Objectives: To ascertain the Belin-Ambrosio indices distribution for Saudi patients aged 6-21 years in Riyadh. Method: Participants in this prospective, cross-sectional, observational, multicenter study ranged in age from 6 to 21 years old and were seen in several no n-ophthalmic emergency departments in Riyadh, Saudi Arabia, in 2017. Scheimpflug corneal tomography system in rotation was used to measure the cornea. Following optometric exams, corneal imaging and KC index measurements were performed using the Pentacam Results: The study's 366 participants were examined once the exclusion criteria were applied. All children's mean and standard deviation (SD) age was 17.41±4.83 years (range: 6–21 years). All Belin-Ambrosio indices percentiles for pediatric, adolescence, and young adult groups are within normal ranges. A comparison between Belin-Ambrosio indices and age demonstrates that the age groups have a statistically significant difference following indices topo astig, BAD Db, BAD Dp, BAD Dt, BAD Da, BAD Dy, BAD D, ART Min, ART Max and ART Avg with p-value 0.05. Also, the correlation coefficient results show a statistically significant correlation between Belin-Ambrosio indices and age with the following indices: Topo Astig, BAD Db, BAD Dp, BAD Dt, BAD Da, BAD Dy, BAD D, ART Min, ART Max, and ART Avg with p-value 0.05 as the age increases BAD Dt and BAD Dy, ART Min, ART Max, and ART Avg decrease. Also, As the age increases, the Topo Astig, BAD Db, BAD Dp, BAD Da, and BAD D increase. The correlation coefficient ranges from 0.11 negative weak to 0.65 negative moderate, and from positive 0.13 to negative strong 0.78. Conclusion:The usual range was seen in the Belin-Ambrosio indices. The Belin-Ambrosio indices and age groups differed statistically significantly.

The Effect of Eyelid Laxity on Corneal Mapping and Corneal Topography.

To evaluate the effect of eyelid laxity on the structure of the cornea. This was a retrospective study performed in one institution. Patients with and without upper and lower eyelid laxity, which were determined using the snap-back test (SBT) and the upper eyelid distraction test (LDT), were evaluated for corneal structural changes with Scheimpflug imaging corneal tomography for the keratometric readings, and cor-neal spectral domain optical coherence tomography for the epithelial thickness (ET) measurements. The ET values were obtained using the statistics report for the superior quadrant (SET), the inferior quadrant (IET) within the 2- to 7-mm region, and central thickness (CET) within the 2-mm region. The minimum corneal thickness values within the central 5-mm region (MinCT) were also included in the study. Keratometric readings (in diopters), horizontal white-to-white (HWTW) measurements, pachymetry, and ET measurements were assessed along with the presence or absence of eyelid laxity. A total of 170 eyes from 85 patients were evaluated (50.6% with eyelid laxity, and 49.4% without eyelid laxity). There was no significant difference between the mean keratometric readings, HWTW, and the mean IET and CET values (P > .05); however, the difference was significant for the MinCT and SET (P < .05). A statistically significant negative correlation was found between the SET values and age, LDT, and SBT measurements (P < .05). A strong association was found between decreased SET and MinCT values and eyelid laxity. The possible reason for these decreases may be inflammation, which plays a role in the pathophysiology of eyelid laxity. [J Refract Surg. 2024;40(11):e783-e791.].

Diagnostic performance of deep learning for infectious keratitis: a systematic review and meta-analysis

Infectious keratitis (IK) is the leading cause of corneal blindness globally. Deep learning (DL) is an emerging tool for medical diagnosis, though its value in IK is unclear. We aimed to assess the diagnostic accuracy of DL for IK and its comparative accuracy with ophthalmologists. In this systematic review and meta-analysis, we searched EMBASE, MEDLINE, and clinical registries for studies related to DL for IK published between 1974 and July 16, 2024. We performed meta-analyses using bivariate models to estimate summary sensitivities and specificities. This systematic review was registered with PROSPERO (CRD42022348596). Of 963 studies identified, 35 studies (136,401 corneal images from >56,011 patients) were included. Most studies had low risk of bias (68.6%) and low applicability concern (91.4%) in all domains of QUADAS-2, except the index test domain. Against the reference standard of expert consensus and/or microbiological results (seven external validation studies; 10,675 images), the summary estimates (95% CI) for sensitivity and specificity of DL for IK were 86.2% (71.6-93.9) and 96.3% (91.5-98.5). From 28 internal validation studies (16,059 images), summary estimates for sensitivity and specificity were 91.6% (86.8-94.8) and 90.7% (84.8-94.5). Based on seven studies (4007 images), DL and ophthalmologists had comparable summary sensitivity [89.2% (82.2-93.6) versus 82.2% (71.5-89.5); P=0.20] and specificity [(93.2% (85.5-97.0) versus 89.6% (78.8-95.2); P=0.45]. DL models may have good diagnostic accuracy for IK and comparable performance to ophthalmologists. These findings should be interpreted with caution due to the image-based analysis that did not account for potential correlation within individuals, relatively homogeneous population studies, lack of pre-specification of DL thresholds, and limited external validation. Future studies should improve their reporting, data diversity, external validation, transparency, and explainability to increase the reliability and generalisability of DL models for clinical deployment. NIH, Wellcome Trust, MRC, Fight for Sight, BHP, and ESCRS.

Multimodal corneal imaging before refractive cataract surgery.

To prospectively review the advances in diagnostics for refractive cataract surgery, focusing on multimodal corneal analysis. The article explores the considerations related to planning refractive cataract surgery, emphasizing its potential to enhance patients' vision performance and quality of life. This review explores preoperative analysis in cataract surgery, focusing on assessing the cornea and ocular surface using multimodal diagnostics, including Placido disk-based corneal topography, Scheimpflug tomography OCT (optical coherence tomography), and biomechanical assessment. Wavefront technology, gene therapy, and artificial intelligence are also relevant in enhancing surgical precision and outcomes. It highlights the importance of preoperative thorough evaluations and technological advancements in ophthalmology. The rapid evolution and advancement of technology enable excellent refractive outcomes in most cases following cataract surgery. Consideration of appropriate preoperative factors is essential for achieving the desired postoperative outcome.

Predicting an opaque bubble layer during small-incision lenticule extraction surgery based on deep learning.

This study aimed to predict the formation of OBL during femtosecond laser SMILE surgery by employing deep learning technology. This was a cross-sectional, retrospective study conducted at a university hospital. Surgical videos were randomly divided into a training (3,271 patches, 73.64%), validation (704 patches, 15.85%), and internal verification set (467 patches, 10.51%). An artificial intelligence (AI) model was developed using a SENet-based residual regression deep neural network. Model performance was assessed using the mean absolute error (E MA ), Pearson's correlation coefficient (r), and determination coefficient (R 2 ). Four distinct types of deep neural network models were established. The modified deep residual neural network prediction model with channel attention built on the PyTorch framework demonstrated the best predictive performance. The predicted OBL area values correlated well with the Photoshop-based measurements (E MA = 0.253, r = 0.831, R 2 = 0.676). The ResNet (E MA = 0.259, r = 0.798, R 2 = 0.631) and Vgg19 models (E MA = 0.31, r = 0.758, R 2 = 0.559) both displayed satisfactory predictive performance, while the U-net model (E MA = 0.605, r = 0.331, R 2 = 0.171) performed poorest. We used a panoramic corneal image obtained before the SMILE laser scan to create a unique deep residual neural network prediction model to predict OBL formation during SMILE surgery. This model demonstrated exceptional predictive power, suggesting its clinical applicability across a broad field.

Prevalence of Keratoconus and Keratoconus Suspect among a sample of Iraqi Children with Refractive Errors: A Cross-Sectional Study

Background: Keratoconus (KC) is a chronic, bilateral, non-inflammatory degenerative condition with severe consequences. Objective: To assess the prevalence of KC and Keratoconus Suspect (KCS) in a pediatric population with astigmatic error ≥1 diopter (D) and non-axial myopia. Methods: Between March and October 2022, a cross-sectional study was done with a group of 6–18-year-old kids with an astigmatic error of ≥1 D or non-axial myopia who went to the pediatric ophthalmology clinic at Ibn Al-Haitham Teaching Eye Hospital in Baghdad, Iraq, for regular checkups. All patients got a thorough eye examination and corneal imaging using the Corneal Tomography System (CSO) Sirius equipment and Scheimpflug technology. Results: The majority of patients were females aged 110–14 years (55%). The frequencies of KC and SKC were 13.5 and 119.6%, respectively. The proportion of KC was substantially higher for those above the age of 14. Patients with KC exhibited considerably larger cylinder and axis measurements. Participants with inferior cones and an asymmetric Bow Tie exhibited greater rates of KC (51.2% and 29.4%, respectively). Except for Pachy-Thin and corneal volume mean values, all other metrics were considerably greater in KC and KCS patients than in control patients. Conclusions: The high prevalence of KC and KCS emphasizes the importance of this issue and the necessity for a systematic strategy for screening in pediatric age groups with refractive error.

Keratoconus.

Keratoconus is a progressive eye disorder primarily affecting individuals in adolescence and early adulthood. The ectatic changes in the cornea cause thinning and cone-like steepening leading to irregular astigmatism and reduced vision. Keratoconus is a complex disorder with a multifaceted aetiology and pathogenesis, including genetic, environmental, biomechanical and cellular factors. Environmental factors, such as eye rubbing, UV light exposure and contact lens wearing, are associated with disease progression. On the cellular level, a complex interplay of hormonal changes, alterations in enzymatic activity that modify extracellular membrane stiffness, and changes in biochemical and biomechanical signalling pathways disrupt collagen cross-linking within the stroma, contributing to structural integrity loss and distortion of normal corneal anatomy. Clinically, keratoconus is diagnosed through clinical examination and corneal imaging. Advanced imaging platforms have improved the detection of keratoconus, facilitating early diagnosis and monitoring of disease progression. Treatment strategies for keratoconus are tailored to disease severity and progression. In early stages, vision correction with glasses or soft contact lenses may suffice. As the condition advances, rigid gas-permeable contact lenses or scleral lenses are prescribed. Corneal cross-linking has emerged as a pivotal treatment aimed at halting the progression of corneal ectasia. In patients with keratoconus with scarring or contact lens intolerance, surgical interventions are performed.

Thyroid gland dysfunction and keratoconus.

The association between keratoconus and thyroid gland dysfunction (TGD) remains controversial. We aimed to determine the frequency of keratoconus among patients with laboratory-confirmed, treatment-naive TGD compared with that of age- and sex-matched healthy controls. Moreover, we investigated the potential relationship between TGD and corneal topographic and tomographic parameters. This multicenter, cross-sectional study recruited individuals with treatment-naive, laboratory-confirmed TGD and sex- and age-matched healthy controls. Demographic and ophthalmic data of all participants were recorded. All participants underwent comprehensive ocular examinations and corneal tomography. Patterns of symmetric bowtie, asymmetric bowtie, asymmetric bowtie/superior steep, asymmetric bowtie/inferior steep, or asymmetric bowtie pattern with a skewed radial axis were documented if present. Furthermore, the maximum simulated keratometry value (Kmax), corneal thinnest thickness (CTT), and back elevation (BE) values were recorded. We measured the serum concentrations of thyroid-stimulating hormone (TSH) and thyroid hormones (free thyroxine [FT4] and free tri-iodothyronine [FT3]) using an immunoassay method. We included 200 eyes of 200 individuals with TGD and 200 eyes of 200 healthy age- and sex-matched controls, with female predominance in both groups. The mean FT4 concentration was significantly higher and the TSH concentration was significantly lower in the TGD group than in the control group (both P < 0.0001), whereas the FT3 level was comparable between groups (P > 0.05). In the TGD group, the frequencies of hyperthyroidism and hypothyroidism were 190 (95%) and 10 (5%), respectively. We found significantly lower mean CTT, higher Kmax, and greater BE values with a significantly higher frequency of abnormal topographic patterns among eyes in the TGD group than in controls (all P < 0.05). The frequency of eyes with keratoconus was significantly higher in the TGD (7.5%) group than in the control (0.5%) group (P < 0.0001). Except for a statistically significant correlation of Kmax (r = - 0.23, P < 0.05) and CTT (r = + 0.15, P < 0.05) with TSH level in the TGD group, no significant correlation was found between corneal characteristics and thyroid profile in either group (all P > 0.05). We observed a higher frequency of keratoconus, with female predominance, in the TGD group. TGD was associated with significant changes in certain corneal topographic and tomographic parameters. Compared with healthy controls, individuals with TGD demonstrated increased Kmax and BE values with more corneal thinning, highlighting the potential association between keratoconus and TGD. However, further large-scale longitudinal studies are essential to confirm our findings.

One-year outcomes after intraocular collamer lens implantation in hyperopic astigmatism: a retrospective single-center study.

Astigmatism is the most prevalent refractive error among children and adults, and it can lead to visual impairment if left uncorrected. The management of compound hyperopic astigmatism is more challenging. This study presents the 12-month outcomes of toric implantable collamer lens (ICL) implantation in eyes with hyperopic astigmatism. This interventional case series included patients with simple or compound hyperopic astigmatism who underwent toric ICL implantation. All eligible individuals underwent a detailed ocular examination. Uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), intraocular pressure, and manifest and cycloplegic refraction results were documented. Pentacam corneal tomography was performed to assess the central corneal thickness, iridocorneal angle width, and anterior chamber depth. Endothelioscopy was performed to determine endothelial cell density. The ICL V4b model was implanted in all the included eyes. Safety and efficacy indices were calculated as postoperative CDVA/preoperative CDVA and postoperative UDVA/preoperative CDVA, respectively. Twenty-six eyes with low-grade simple or compound hyperopic astigmatism were included. All eyes experienced a significant improvement of four lines in postoperative UDVA (P < 0.001), and their postoperative CDVA remained stable at the 12-month follow-up (P > 0.05). The safety and efficacy indices were 1.0. None of the eyes lost two or more lines of CDVA; in 81% of the eyes, CDVA was unchanged, and the proportion of eyes with 20/30 or better postoperative UDVA was identical to that with 20/30 or better preoperative CDVA (81% for each). The mean manifest spherical equivalent at the 12-month postoperative visit had significantly improved (P < 0.001). The percentages of eyes with postoperative spherical equivalent within ± 0.50 D and ± 1.00 D were 81% and 96%, respectively. The postoperative refractive cylinder improved significantly (P < 0.05), and the percentage of eyes with refractive cylinder within ± 0.50 DC and ± 1.00 DC were 50% and 77%, respectively. Our outcomes indicate that toric ICL implantation is safe and effective for managing low-grade simple or compound hyperopic astigmatism. The proportion of eyes with 20/30 or better postoperative UDVA was identical to that with a 20/30 or better preoperative CDVA. The manifest spherical equivalent and refractive cylinder were significantly reduced. No serious safety concerns were observed. Further prospective large-scale studies with a wide range of ages and grades of hyperopic astigmatism are required to verify these preliminary outcomes.

Cessation of contact lenses prior to corneal tomography for keratoconus monitoring: results from a clinician survey.

Cessation of contact lenses prior to corneal tomography for keratoconus monitoring: results from a clinician survey.

Assessing the predictability of five intraocular lens calculation methods in eyes with prior myopic keratorefractive lenticule extraction.

To evaluate and compare the predictability of five methods of intraocular lens (IOL) calculation in eyes with prior keratorefractive lenticule extraction (KLEx) for the treatment of myopia. A retrospective case study included 100 eyes of 52 patients who underwent myopia and myopia with astigmatism treatment with small incision lenticule extraction (SMILE). Preoperative and 3-month postoperative measurements of optical biometry and corneal tomography were obtained. The spherical equivalent of the refractive change induced by surgery was converted to the corneal plane (SMILE-dif). A physically well-defined method was developed in which the same IOL model was implanted before and after SMILE. IOL power was calculated using ray-tracing (RT-Sirius), and several IOL power calculation formulas (Kane, EVO 2.0, Barrett Universal II Formula, Hoffer QST) before surgery. After surgery, IOL power was calculated with RT-Sirius, Kane using Mean Pupil Power at 5.5mm by ray tracing, EVO 2.0 Post Myopic LASIK/PRK, Barrett True K and Hoffer QST Post Myopic LASIK/PRK after surgery. The difference between the refractive error induced by the IOL before and after SMILE in the corneal plane (IOL-dif) was compared with SMILE-dif. The predicted error (PE) was calculated as the difference between SMILE-dif and IOL-dif. The PE obtained was 0.26 ± 0.55 diopters (D), 0.10 ± 0.45 D, 0.40 ± 0.37 D, -0.03 ± 0.36 D, 0.02 ± 0.51 D, with RT-Sirius, Kane, EVO 2.0, Barrett True K, and Hoffer QST respectively. PE was not statistically significantly different between Barrett True K and Hoffer QST, with differences being more homogeneous with Barrett, (variance σ2 = 0,13). The absolute EP obtained with Barrett True K achieved 84% of cases within ± 0.5 D, followed by Kane (72%), Hoffer QST (65%), EVO (61%) and RT-Sirius (59%). Barrett True K formula was the most accurate method for IOL calculation in eyes that had undergone SMILE for the correction of myopia. What is known The literature regarding IOL power calculation after SMILE is sparse, and the methods used to estimate corneal power following LASIK/PRK may not be applicable to SMILE procedures. The most common approach to investigating the predictability of IOL calculation formulas involves a theoretical model encompassing the virtual implantation of an IOL. What is new The Hoffer QST formula, Kane formula using Mean Pupil Power at 5.5mm, EVO 2.0, and Sirius' Ray Tracing software had not been previously evaluated using this approach. The Barrett True K formula was the most accurate method for IOL calculation in eyes that had undergone SMILE for myopia correction, outperforming Ray Tracing.

Inflammatory and genomic interactions within keratoconus susceptible patients: a nationwide registered case–control study

PurposeThis study aimed to investigate the association between variants in the interleukin (IL)-1 gene cluster and susceptibility to keratoconus (KC) in an Iranian population.MethodsIn the case group, there were 188 KC patients diagnosed by clinical findings and corneal tomography. The control group included all 205 healthy controls with no personal or family history of eye-related, metabolic, or immune system-related disease. Using the standard salting out extraction procedure, genomic DNA was isolated from peripheral blood leukocytes. The genotypes were determined by applying agarose gel electrophoresis for the IL-1RN 86 bp VNTR and polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) for rs16944 and rs1143634.ResultsThe results showed a significant association between the IL-1β rs1143634 (rs1143634 T allele, P = 0.008) and IL-1RN 86 bp VNTR polymorphisms (LL and LS genotype, P = 0.048 and 0.012 respectively) and susceptibility to KC in the Iranian population. The genotype distributions of rs1143634 (P = 0.004) and rs2234663 (P = 0.042) significantly differed between case and control groups, with certain genotypes demonstrating a protective effect against KC. Logistic regression analysis revealed a protective effect of the IL-1RN L allele [odds ratio (OR) = 0.367, 95% confidence interval (CI): 0.240–0.562; P = 0.000] and certain haplotypes (OR = 0.628, 95% CI: 0.447–0.884; P = 0.007) against KC. However, no significant association was found for the IL-1β rs16944 polymorphism.ConclusionThis study provides evidence for an association between variants in the IL-1 gene cluster and susceptibility to KC in an Iranian population. Further research on larger and more diverse populations is warranted to validate these findings and explore the underlying mechanisms involved.

The Increase in Corneal Stiffness After Accelerated Corneal Cross-Linking in Progressive Keratoconus Using Different Methods of Epithelial Debridement.

The purpose of this study was to investigate corneal stiffening after epithelium-off accelerated corneal cross-linking (CXL; 9 mW/cm²) in progressive keratoconus (KC) with different methods of epithelial debridement. This was a retrospective, interventional, and non-randomized study. In group 1, the epithelium was removed using a hockey knife (N = 45). In group 2 (N = 39) and group 3 (N = 22), the epithelial thickness was measured by optical coherence tomography (OCT) and the epithelium was ablated by excimer laser, but, in group 3, stromal ablation was performed additionally to correct high order aberrations (HOAs). Corneal biomechanics (integrated invers radius [IIR], stress-strain index [SSI]) and corneal tomography (thinnest corneal thickness [TCT]) were assessed with Corvis ST and Pentacam prior to and 1 month after CXL. Corneal tomography did not differ among the groups preoperatively (P > 0.05). TCT decreased significantly in all groups after surgery (all P < 0.05). Nonetheless, corneal biomechanical stiffening was found in all three groups indicated by a decreased IIR and an increased SSI (all P < 0.05). For group 3, the HOA improved significantly (P < 0.001). Among the groups, there were no significant differences in changes of biomechanical parameters, but TCT was significantly reduced after laser ablation. Corneal stiffening after CXL is independent from epithelial removal. In particular, despite the removal of stromal tissue to correct HOA, a stiffening effect was achieved in keratoconic corneas, even it was less pronounced compared to mechanical epithelial removal. The reduction in HOA indicates a possible improvement in visual acuity. Cross-linking stiffens the keratoconus independent of epithelial debridement technique and may compensate minor stromal laser ablation.

Corneal Epithelial Hyperplasia Related to Chronic Eye Rubbing Mimicking Keratoconus.

We report a case of corneal epithelial hyperplasia associated with chronic eye rubbing mimicking keratoconus. A 32-year-old man was presented with a 3-year history of suboptimal vision and astigmatism in his left eye. His history was significant for chronic left eye rubbing. The anterior corneal curvature map showed inferior steepening in the left eye; however, other features of ectasia were absent. Corneal epithelium thickness mapping with optical coherence tomography was significant for corresponding epithelial thickening. His corneal imaging remained stable at a 6-month follow-up examination. At month 15-and after cessation of eye rubbing behavior-the vision symptoms, refraction, and corneal imaging had normalized. In conclusion, chronic eye rubbing may cause reversible corneal epithelial hypertrophy. Eye rubbing should be considered in the evaluation of patients presenting with unexplained vision symptoms and changes in astigmatism that are not consistent with ectasia on corneal imaging.

One-Year Results of a Posterior Chamber Toric Phakic Intraocular Lens Implantation in Patients with Keratoconus.

To determine clinical and refractive results after the implantation of EyeCryl Phakic Toric intraocular lens in patients with stable keratoconus. The study included all patients diagnosed with keratoconus who underwent implantation of an EyeCryl Phakic Toric intraocular lens (Biotech Healthcare Holding; Ahmedabad, India) in at least one eye and had a follow-up of at least 12 months. Visual and refractive data were collected for all patients, along with corneal tomography measurements using Pentacam, and vault measurement using optical coherence tomography. This retrospective study was conducted at a high-volume private refractive surgery center in Medellín, Colombia. A total of 83 eyes from 47 patients were included in the study. The majority (71.1%) were female, with a mean age of 31.2 ± 5.1 years. After 12 months of follow-up post-surgery, the spherical equivalent improved significantly from -8.19 ± 4.04 D to -0.06 ± 0.48 D (p < 0.001). Furthermore, 77% of eyes had a post-surgical spherical equivalent within ±0.50 D, while 92% had residual astigmatism ≤0.50 D. Twelve months after surgery, mean manifest astigmatism was -0.28 ± 0.27 D. Uncorrected visual acuity also showed improvement, from 1.11 ± 0.35 LogMAR to 0.14 ± 0.11 LogMAR. Moreover, 52.4% of eyes demonstrated an improvement of at least one line in best-corrected visual acuity. Notably, no intraoperative or postoperative complications were observed in the study population. The implantation of EyeCryl Phakic Toric intraocular lenses represents a highly effective and safe option for correcting refractive errors in patients with a history of keratoconus. Refractive accuracy is excellent, and a significant proportion of patients experienced an improvement in their best-corrected vision by at least one line.

Corneal nerve changes by anti-glaucoma medications examined by in vivo confocal microscopy.

To evaluate the effects of antiglaucoma eye drops on corneal nerves by in vivo confocal microscopy (IVCM). This study comprised 79 patients diagnosed with glaucoma and 16 healthy control individuals. Among the glaucoma patients, 54 were treated with medication, while 25 remained untreated. Central corneal images were evaluated by IVCM, and then ACCMetrics was used to calculate the following parameters: corneal nerve fiber density (CNFD), branch density (CNBD), fiber length (CNFL), total branch density (CTBD), fiber area (CNFA), fiber width (CNFW), and fractal dimension (CNFrD). The correlation between IVCM parameters and drugs was evaluated using non-parametric measurements of Spearman's rank correlation coefficient. The CNFD was reduced in glaucoma groups compared to healthy subjects (P<0.01). Patients using anti-glaucoma medications exhibited poorer confocal parameters compared to untreated patients. As the number of medications and usage count increased, CNFD, CNBD, CNFL, CTBD, CNFA, and CNFrD experienced a decline, while CNFW increased (all P<0.01). For the brinzolamide-therapy group, there was a significant decrease in CNFD and CNFL compared to the other monotherapy groups (P<0.001). In the absence of medication, CNFD in males was lower than that in females (P<0.05). Among patients under medication therapy, CNFD remained consistent between males and females. Antiglaucoma eye drops affect the microstructure of corneal nerves. IVCM and ACCMetrics are useful tools that could be used to evaluate the corneal nerve changes.

Ocular Manifestations in Seborrheic Dermatitis Epidemiology, Clinical Features, and Management: A Comprehensive Review.

Seborrheic dermatitis (SD) often leads to ocular manifestations (OM) that are frequently overlooked. This study comprehensively explains the genesis of these ocular issues, which involves a combination of Malassezia overgrowth, changes in sebum production, and inflammatory responses in the body. The periocular region is rich in sebaceous glands, allowing Malassezia to thrive, which can lead to an inflammatory reaction that spreads to the eye surface, causing disorders such as blepharitis, conjunctivitis, keratitis, and ocular surface diseases. Although epidemiological data are limited, it is well established that ocular involvement occurs in approximately 10%-40% of individuals with SD. Early detection and treatment are crucial to prevent potential vision-threatening complications. A comprehensive diagnostic approach is necessary, including clinical examination, slit-lamp biomicroscopy, tear film analysis, and corneal imaging. Managing these conditions requires a multidisciplinary strategy involving collaboration between dermatologists and ophthalmologists. The treatment should involve topical and systemic medications to address the skin and ocular components. Patient education is critical for improving adherence to therapy, self-management, and the early identification of problems. In the future, it will be essential to investigate the intricate interactions between Malassezia species and host immunological processes. This collective effort will involve creating new biomarkers and diagnostic tools, investigating targeted immunomodulatory drugs and novel lipid-based medicines as potential treatments, and conducting large-scale longitudinal studies to understand the epidemiological patterns and prognostic variables better. By raising awareness, encouraging collaboration across disciplines, and advancing research, healthcare practitioners can significantly improve patients' quality of life with SD and OM.