Search Results (79)

Background/Objectives: Keratoconus (KC) is a corneal ectatic disease, characterized by the progressive thinning of the cornea, myopia, and astigmatism, which lead to a decrease in visual acuity. Corneal collagen crosslinking (CXL) is an efficient method of stopping the progression of the disease. The objective of this study is to investigate the endothelial and biomechanical properties of the cornea in keratoconus patients, before and after undergoing corneal collagen crosslinking. Methods: A total of 66 eyes were diagnosed with progressive keratoconus and were recommended epi-off corneal crosslinking. Before the procedure, they were investigated with corneal topography (for minimum, maximum, average keratometry, and corneal astigmatism), specular microscopy (for the following endothelial cell parameters: number, density, surface, variability, and hexagonality), and an ocular response analyzer (for the following biomechanical parameters: corneal hysteresis and resistance factor). All measurements were repeated 1 month and 6 months after the intervention. Results: Several parameters differ according to the Amsler–Krumeich stage of keratoconus: in more advanced stages, patients present higher endothelial cell variability, a lower number of endothelial cells in the paracentral region of the cornea, lower CCT and CRF, and higher keratometry and astigmatism. Endothelial cell variability and number correlate with average keratometry, and there are also strong correlations between topography and CH and CRF. After CXL, the paracentral number of endothelial cells decreased; cell variability and average cell surface increased. Conclusions: More advanced keratoconus cases present with altered corneal biomechanics and topographical parameters, the endothelial layer also being affected proportional to the stage of the disease and also slightly affected after corneal collagen crosslinking. Full article

Background/Objectives: Swept-Source Optical Coherence Tomography (SS-OCT) is a novel optical biometry technology with limited published data on its reliability compared to the gold standard, partial coherence interferometry (PCI). This study aims to assess the agreement between an SS-OCT biometer (Argos) and a PCI device (IOLMaster 500) in terms of biometry values, intraocular lens (IOL) power calculation and mean prediction error (ME). Methods: In this prospective comparative study, axial length (AL), anterior chamber depth (ACD), flat (K1), steep (K2) and mean (Km) keratometry values, astigmatism power, J0, and J45 vector components, white-to-white distance (WTW), and IOL power calculations for nine IOL models using four formulas were compared in cataract patients. Refractive outcomes were assessed in eyes implanted with SN60WF and Panoptix IOLs, with ME calculated for each module and formula for both IOLs postoperatively. Results: This study included 133 eyes (mean age: 66.0 ± 10.95 years). Argos measured significantly higher ACD and steeper keratometry values than IOLMaster, albeit without significant differences in AL, astigmatism power, WTW, J0, and J45. Mean IOL power differences were within the clinically acceptable threshold (0.50 D), except for SN6ATx with Hoffer Q and Haigis, and Clareon with Haigis. For Panoptix and SN60WF, IOLMaster demonstrated a more hyperopic ME than Argos with SRK/T, Holladay 1, and Hoffer Q; however, this was without clinically significant differences. Conclusions: Argos and IOLMaster 500 presented differences in ACD, keratometry values, and IOL power calculation. However, both devices showed non-clinically significant differences in IOL power calculation and ME in the majority of formulas. Full article

Background/Objectives: To evaluate the efficacy, accuracy, safety, and long-term stability of topography-guided photorefractive keratectomy (TGPRK) in eyes where post-LASIK (PLE) ectasia progression was stabilized with under-flap corneal crosslinking (ufCXL). Methods: This retrospective interventional case series included six eyes from five patients with PLE after microkeratome LASIK. All eyes underwent ufCXL to halt ectatic progression. A shallow TGPRK enhancement was performed on the LASIK flap surface after corneal and refractive stability was confirmed (18 months median) post ufCXL Outcome measures included uncorrected and corrected distance visual acuity (UDVA, CDVA), spherical equivalent (SEQ), refractive astigmatism, keratometry, and corneal irregularity indices over a mean follow-up of 47 months. Results: ufCXL stabilized ectatic progression but left residual refractive errors, limiting UDVA. TGPRK performed subsequently significantly improved UDVA, from 0.38 to 0.10 LogMAR (p = 0.017), and increased the LASIK efficacy index from 0.46 to 0.83 (p = 0.0087). Refractive astigmatism was reduced in all eyes achieving a SEQ within ±1.00 D of the target. Long-term stability was maintained, with no ectasia progression, no change in SEQ, no change in corneal irregularity indices, and no increase in maximal keratometry. Conclusions: TGPRK performed in ufCXL stabilized corneas can safely correct residual refractive errors, resulting in significant and sustained improvements in both refractive and visual outcomes in PLE. Full article

Background: While keratoconus (KC) has traditionally been classified as a non-inflammatory corneal disorder, emerging evidence suggests that inflammatory processes may be involved in its pathogenesis. This study investigated whether systemic inflammation contributes to KC development by measuring serum levels of key pro-inflammatory cytokines in KC patients compared to healthy controls. Methods: This cross-sectional comparative study included 60 participants aged 18–30 and was divided into three equal groups: healthy controls, progressive KC, and stable KC. The levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β) in the serum were measured through an enzyme-linked immunosorbent assay. KC severity was classified based on mean keratometry values. Results: There were no significant differences detected in serum IL-6, TNF-α, and IL-1β levels across groups (p > 0.05). Moreover, no significant correlations were found between systemic cytokine levels and KC severity categories (p > 0.05). Conclusions: Systemic levels of IL-1β, IL-6, and TNF-α do not significantly differ between KC patients and controls nor do they correlate with disease severity, reinforcing the hypothesis that KC involves primarily local inflammatory processes. Full article

Objective: This research seeks to investigate the effects of preoperative intense pulsed light with manual meibomian expression (IPL-MGX) on the refractive accuracy of cataract surgery on dry eyes with meibomian gland dysfunction (MGD-related dry eyes). Methods: Fifty-six MGD-related dry eye cases planned for cataract surgery were analyzed. IPL-MGX (four times at 2-week intervals) was performed before preoperative examination. Axial length (AL), anterior chamber depth (ACD), corneal curvature (mean-K), tear break-up time (TBUT), superficial punctate keratopathy in the central cornea (C-SPK), corneal higher-order aberrations (HOAs), and predicted postoperative spherical equivalent (P-SE) were evaluated pre- and post-IPL-MGX. The postoperative subjective spherical equivalent (S-SE) was evaluated after one month. The absolute difference between the S-SE and P-SE was considered an indication of P-SE accuracy. Changes in all the variables were assessed before and after IPL-MGX treatment. Results: No significant differences were observed in AL or ACD (p = 0.85, 0.56). The differences in mean-K, TBUT, C-SPK, and HOAs were significant (p < 0.01). P-SE accuracy based on post-IPL-MGX data was significantly higher than that based on pre-IPL-MGX data (p < 0.01). P-SE accuracy was within 0.25 diopters (D) in 14.3% of pre- and 55.4% of post-IPL-MGX, within 0.5D in 55.4% of pre- and 92.9% of post-IPL-MGX, within 0.75D in 98.2% of pre- and post-IPL-MGX, and within 1.0D in 98.2% of pre- and 100% of post-IPL-MGX. In the range of 0.25 and 0.5 D, the accuracy of P-SE was significantly higher in post-IPL-MGX (p < 0.01). Conclusions: Preoperative IPL-MGX considerably improved the predicted postoperative refraction accuracy in patients with MGD-related dry eye undergoing cataract surgery. Full article

Background and Objectives: Scleral lenses are widely used for visual rehabilitation in keratoconus patients, but their long-term effects on corneal tomography remain unclear. This study aims to evaluate the impact of 12-month scleral lens wear on corneal tomography in keratoconus patients through a case-controlled design. Materials and Methods: This retrospective study included 220 keratoconus patients, of whom 10 eyes were treated with SoClear (Brighten Optix Corporation, Taipei, Taiwan) mini-scleral lenses for over one year (SL group). A control group of 14 eyes was matched using Mahalanobis distance matching based on anterior maximum keratometry (K_max) and age. Both groups were evaluated at baseline and 12 months. Corneal tomography was assessed using the Pentacam HR (Oculus, Wetzlar, Germany), analyzing parameters such as anterior and posterior corneal curvature, thinnest corneal thickness (TCT), and higher-order aberrations. Generalized estimating equations (GEEs) were employed to assess the time-by-treatment effect between the two groups. Results: The SL group included 10 eyes from eight patients (seven males, one female; mean age 30.40 ± 6.52 years), while the control group included 14 eyes from 11 patients (three males, wight females; mean age 27.43 ± 8.11 years). Best corrected visual acuity with spectacles improved significantly with scleral lenses (p = 0.011) and remained stable (p = 0.044) at 12 months. Significant interaction effects were found in Ambrósio relational thickness (p = 0.006), posterior radius curvature (p = 0.047), posterior mean keratometry (p = 0.019), posterior flat keratometry (p = 0.023), and thinnest corneal thickness angle (p = 0.023); the SL group demonstrated less progression in these parameters compared to the control group. Conclusions: This case-controlled study highlights the 12-month impact of scleral lenses on keratoconus, showing improved visual acuity compared to spectacles, stabilized posterior corneal curvature, and maintained corneal thickness. Further prospective studies with larger cohorts are needed to assess scleral lens effect on keratoconus progression. Full article

Background and Objectives: The objective was to assess ocular biometric measurements in relation to age and gender among patients scheduled for cataract surgery, utilizing an optical biometry device. Materials and Methods: The optical biometric parameters evaluated included axial length (AL), central corneal thickness (CCT), anterior chamber depth (AD), lens thickness (LT), horizontal corneal diameter (WTW), and keratometry values in the flat (K1) and steep (K2) meridians. Astigmatism (AST) was also measured as the difference between these keratometry values. Results: A total of 14,183 optical biometric measurements were included in the study. The average age of the participants was determined to be 56 (3–110) years. The average AL was 23.57 ± 1.45 mm, the average AD was 2.76 ± 0.42 mm, the average CCT was 518.13 ± 37.81 μm, the average WTW distance was 11.88 ± 0.59 mm, and the average LT was 4.19 ± 0.51 mm. The keratometry measurements were recorded as K1 = 43.39 ± 1.96 diopters (D), K2 = 44.51 ± 2.31 D, and AST = 1.12 ± 1.15 D. The average values for male eyes in terms of the AL, AD, WTW, and LT measurements were significantly higher than those for female eyes (p = 0.001). The average K1 and K2 values were flatter in males than in females, while the AST value was found to be higher in females (p = 0.001). As age progressed, the mean AL decreased, the CCT decreased, the AD narrowed, the WTW distance decreased, the LT increased, and the keratometric values K1, K2, and AST decreased until the age of 60, after which they increased again. Conclusions: Research indicates that the measurements of the bulbus oculi are generally larger in males than in females. Furthermore, each of the optical biometric measurements is interrelated. Over time, these measurements may change. Full article

Background/Objectives: To evaluate the timing and extent to which late keratometric changes can occur between year 7 and 12 after corneal collagen crosslinking (CXL) in patients with keratoconus. Methods: A subgroup of a retrospective cohort study of all consecutive patients who underwent CXL at our cornea center between 2007 and 2011 was analyzed. The inclusion criteria consisted of CXL according to the Dresden protocol and a full set of keratometry parameters collected by Scheimpflug tomography preoperatively and at year 7, 9 and 12 after CXL. Results: A total of 46 eyes of 35 patients were included. The most relevant keratometric parameters (Kmax, TCT, K1, K2 and anterior astigmatism) decreased statistically significantly at year 7 after CXL, while there was no relevant difference for posterior astigmatism and the flat axes of anterior and posterior astigmatism. All keratometric parameters (except for K2) remained stable between year 7 and 12 without statistically significant change, according to mixed effect model regression analysis. BCVA improved statistically significant between the baseline and year 7 and remained stable until year 12. Suspected disease progression was noted in two patients (4.3%) between year 7, 9 and 12 post-CXL. Conclusions: Keratometric and functional results improve significantly 7 years after CXL in comparison to preoperative values and show very effective stabilization without clinically relevant changes up to year 12. However, while the risk of disease progression decreases remarkably after 7 years, in rare cases, suspected progression can occur even up to year 12. Therefore, regular control visits with keratometry measurements are advisable at least every 2 to 3 years in the late postoperative course. Full article

Background/Objectives: To evaluate the clinical efficacy and safety of combined phacoemulsification, extended depth-of-focus (EDOF) intraocular lens (IOL) implantation, and epiretinal membrane (ERM) peeling during vitrectomy surgery for treating patients with ERM, cataracts, and presbyopia. Methods: Patients with preexisting low-grade ERM who underwent cataract surgery with the implantation of an EDOF IOL were included. Corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), autorefraction and keratometry, manifest refraction, and central foveal thickness (CFT) were measured before surgery and at postoperative months 3 and 6. A monocular defocus curve was measured 6 months postoperatively. Furthermore, patients were instructed to report symptoms of photic phenomena at each visit. Results: In total, 16 eyes of 16 patients (median age, 59.5 years) were included in this study. Compared with those at baseline, the CDVA, UDVA, UIVA, UNVA, and CFT significantly improved at 3 and 6 months postoperatively. The defocus curve revealed that a visual acuity of 0.12 logarithm of the minimal angle of resolution or better was maintained from +0.5 to –1.5 diopters. No patients reported visual disturbances suggestive of photic phenomena, such as glare or halo. Conclusions: EDOF IOL implantation had excellent outcomes, including improved distance and intermediate visual acuity, functional near visual acuity, and absence of visual symptoms in patients who received phacovitrectomy to treat low-grade ERM. Full article

We aimed to determine the effects of night-shift work on corneal parameters in thirty-five healthy individuals (24–59 years) in a retrospective cohort study. Among them, 12 hospital nurses regularly worked two shifts, spending a third of their nights awake, whereas 23 age-matched controls never worked shifts and slept regularly. Measurements were performed at least five times within 12 h. We analyzed the keratometric parameters of the corneal front (F) and back (B) surfaces, including the refractive power in the flattest and steepest axes (K1, K2), astigmatism (Astig); and corneal pachymetry (Pachy) at the thinnest corneal point and pupil center, volume relative to the 10 mm corneal diagonal (Vol D10); and surface variance index (ISV). A multilevel mixed-effects linear regression adjusted for age was applied to 905 measurements. All parameters exhibited significant periodic fluctuations (p ≤ 0.005). The two groups also showed significantly different periodic fluctuations (p ≤ 0.008), except in K1B and AstigB. K1/K2 (F and B), AstigF, Pachy, and ISV differed significantly (p < 0.0001). Surprisingly, prolonged night shift work did not increase the ISV, and no evidence of age-related corneal thinning was observed. Long-term night-shift exposures change various corneal parameters, reflecting both concomitant and adaptive effects. This study highlights the impact of consistent sleep deprivation on corneal properties, warranting further research into understanding the long-term effects of night-shift work. Full article

Background/Objectives: This study aimed to evaluate long-term postoperative outcomes following the use of small-diameter grafts in Descemet Membrane Endothelial Keratoplasty (DMEK) procedures. Methods: Thirty-four eyes were evaluated after DMEK surgery. Best-corrected visual acuity (BCVA), endothelial cell density (ECD), endothelial cell loss (ECL), central corneal thickness (CCT), mean keratometry (MK), mean astigmatism (MA), astigmatism asymmetry (AA), and higher-order aberrations (HOA) were assessed at baseline and 12, 24 and 36 months after surgery using anterior segment swept-source OCT (CASIA2, Tomey, Japan). Results: BCVA gradually improved during the 12-month follow-up, after which the stabilisation of this parameter was documented. Compared with the donor values, the cumulative median ECL reached approximately 63.95% over 36 months. No significant changes in total keratometry between baseline recordings and 36-month data were observed. Total astigmatism power significantly decreased between baseline and the 12th month and subsequently between the 12th and 24th month, with consecutive stabilisation of astigmatism power from the 24th month to the 36th month of follow-up. Significant reductions in HOA were observed until the 12th month, followed by the stabilisation of these parameters. Conclusions: The use of smaller grafts in DMEK demonstrates high effectiveness in maintaining high visual and refractive quality while offering potential advantages in tissues. Full article

Background: We evaluate the accuracy of intraocular lens (IOL) power calculation in the following formulas—Barrett True-K No History (BTKNH), EVO 2.0 Post-Hyperopic LASIK/PRK (EVO 2.0), Haigis-L, Pearl-DGS, and Shammas (SF)—with patients who have undergone cataract surgery at the Eye Unit of University of Campania Luigi Vanvitelli, Naples, Italy, and had prior hyperopic laser refractive surgery. Methods: A monocentric, retrospective, comparative study, including the charts of patients who had undergone cataract surgery and previous hyperopic laser refractive surgery, was retrospectively reviewed. Patients with no other ocular or systemic disease which might interfere with visual acuity results and no operative complications or combined surgery were enrolled. The mean absolute prediction error (MAE) was calculated for each formula and compared. Subgroup analysis based on the axial length and mean keratometry was performed. Results: A total of 107 patients (107 eyes) were included. The MAE calculated with SF provided less accurate (p < 0.05) results when compared to both BTKNH and EVO 2.0 formulas. The MAE obtained using Haigis-L, EVO 2.0, Pearl-DGS, and BTKNH showed no significant differences. Conclusions: The analysis of the accuracy of the selected formulas shows no clear advantage in using one specific formula in standard cases, but in eyes where it is mandatory to reach the target refraction, SF should be avoided. Full article

Background/Objectives: Transepithelial accelerated corneal crosslinking (TE-ACXL) is a minimally invasive approach for stabilizing progressive keratoconus while preserving the corneal epithelium. This study aims to evaluate changes in visual acuity, refractive error, and corneal parameters before and six months after TE-ACXL. Methods: A retrospective analysis was conducted on 30 eyes from 20 patients who underwent TE-ACXL between May 2021 and June 2023. Variables included were uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), spherical and cylindrical refractive error, and corneal tomography parameters such as maximum keratometry (Kmax), the symmetry index (Si), the keratoconus vertex (KV), Baiocchi–Calossi–Versaci index (BCV), thinnest corneal thickness (TCT), and central corneal thickness (CCT). Results: CDVA improved from 0.20 ± 0.22 to 0.06 ± 0.11 LogMAR (p = 0.004), while UDVA improved from 0.47 ± 0.35 to 0.29 ± 0.30 LogMAR (p < 0.001). Spherical and cylindrical refractive error showed significant reductions from −2.18 ± 3.05 D to −1.31 ± 1.84 D (p < 0.001) and −3.33 ± 1.98 D to −2.33 ± 1.52 D (p < 0.001), respectively. Pachymetry values decreased significantly, with TCT reducing from 466.43 ± 31.24 µm to 438.63 ± 30.54 µm (p < 0.001) and CCT from 480.80 ± 33.24 µm to 451.23 ± 29.26 µm (p < 0.001). Kmax showed a modest reduction (52.33 ± 3.51 D to 51.19 ± 3.63 D, p < 0.001), while other topographic indices, including Si, KV, and BCV, exhibited minor, non-significant changes, except for BCV back (p = 0.031). Conclusions: TE-ACXL was associated with significant improvements in visual acuity and refractive stability at six months postoperatively while maintaining a favorable safety profile. The procedure may serve as an effective option for early intervention in progressive keratoconus. Full article

Background/Objectives: Accurate biometric measurements are critical for achieving optimal refractive outcomes in cataract surgery. This study evaluated the agreement of biometric measurements between a swept-source optical coherence tomography (SS–OCT) biometer (Argos^®, Movu Inc.) and an optical low-coherence interferometry (OLCI) biometer (Aladdin^®, Topcon Corp.). Parameters analyzed included axial length (AL), anterior chamber depth (ACD), lens thickness (LT), keratometry (K1, K2), and white-to-white corneal diameter (WTW). Methods: A total of 170 eyes were examined, and agreement was assessed using Bland–Altman analysis, intraclass correlation coefficients (ICCs), and Pearson correlation coefficients. Results: Excellent agreement was observed for AL (ICC = 0.975), ACD (ICC = 0.960), LT (ICC = 0.951), K1 (ICC = 0.921), and K2 (ICC = 0.927). Moderate agreement was found for astigmatism axis (ICC = 0.655) and cylinder power (ICC = 0.891). Poor agreement was noted for astigmatism-related Jackson cross-cylinder vectors J0 (ICC = 0.334) and J45 (ICC = −0.311), as well as for WTW (ICC = 0.338). Bland–Altman plots demonstrated narrow limits of agreement for most parameters, with mean differences of 0.009 mm for AL and 0.06 mm for ACD. Conclusions: Both devices demonstrated high degrees of agreement for core biometric parameters, supporting their clinical interchangeability. However, the variability in WTW and astigmatism-related measurements highlights the need for caution when precise corrections are required. Full article

Background: Corneal allogenic intrastromal ring segments (CAIRSs) offer a novel, biocompatible alternative to synthetic intracorneal ring segments (ICRSs). This review aims to evaluate the clinical outcomes of CAIRS. Methods: Inclusion criteria were studies with a minimum of 20 eyes and six months of follow up. The primary outcome measure was uncorrected distance visual acuity (UDVA). The secondary outcomes were a change in corrected distance visual acuity (CDVA), spherical equivalent (SE), mean keratometry (K-mean), maximum keratometry (K-max), K1, K2, and pachymetry. Results: The primary outcome UDVA improved from 0.83 ± 0.15 to 0.40 ± 0.08 logMAR (p = 0.01), while CDVA improved from 0.52 ± 0.22 to 0.19 ± 0.09 logMAR (p = 0.01). K-max decreased from 57.8 ± 1.09 D to 53.57 ± 2.66 D (p < 0.01), and K-mean reduced from 49.27 ± 0.28 D to 45.30 ± 1.46 D (p < 0.01). An average of 84.92% ± 11.4% of eyes had an improvement in UDVA. No major complications or significant visual acuity deterioration were reported. Conclusions: CAIRSs serve as an alternative to synthetic ICRSs and even corneal transplantation in some cases. They represent a safe, effective, and biocompatible promising advancement in corneal ectasia management to improve visual acuity and corneal topography with minimal complications. Full article