Tiago Monteiro

Background/Objectives: This study aims to review the evolution of preoperative ectasia risk assessment before laser vision correction (LVC), with particular emphasis on the changing role of corneal pachymetry and its interpretation within contemporary multimodal screening strategies. Methods: A structured narrative review of the literature was conducted to examine the historical development of ectasia screening, the incorporation of pachymetric parameters into successive risk models, and the available evidence regarding refractive outcomes in constitutionally thin corneas undergoing laser vision correction. Results: Preoperative ectasia screening has evolved from reliance on isolated clinical and topographic parameters to comprehensive multimodal assessment integrating corneal tomography, biomechanics, epithelial thickness mapping, and artificial intelligence-based indices. Although corneal pachymetry remains a key component of most contemporary risk models, increasing evidence suggests that constitutionally thin corneas with otherwise normal tomographic and biomechanical profiles can achieve favourable outcomes following surface ablation. However, the available evidence remains limited by retrospective study designs, highly selected populations, and insufficient long-term follow-up. Conclusions: Corneal thickness should no longer be interpreted as an isolated indicator of ectasia risk but rather as one component of an integrated assessment of corneal susceptibility. Contemporary preoperative screening should prioritise individualised multimodal evaluation over reliance on isolated pachymetric thresholds. At the same time, further prospective studies are needed to define the long-term safety of surface ablation in constitutionally thin corneas.

Purpose: To describe and compare the efficacy and safety profile of posterior chamber implantable collamer lens (ICL) implantation in eyes with low-vault and non–low-vault over a 5-year follow-up period. Setting: Hospital de Braga, Braga, Portugal. Design: Retrospective, comparative, cohort study. Methods: 2 groups were created based on the first postoperative vault measurement evaluation (1 month): group 1 (P = .224 and P = .390, respectively). Respectively, 80 (76.2%) and 201 (70.5%) eyes were within ±0.50 diopter of targeted refraction. There was a significant reduction in vault measurements in both groups ( P = .034 and P < .001, respectively). No significant differences between groups in endothelial cell density loss were noted ( P = .096). The low-vault group presented a higher incidence of crystalline lens opacities/cataracts (5.6% vs 1.7%), although only 1 patient in group 2 was submitted to cataract surgery. Conclusions: ICL implantation for surgical correction of myopia yielded stable visual results with excellent safety and efficacy indexes in patients with low vault.

Purpose: To investigate the safety and effectiveness of a monofocal enhanced depth-of-focus intraocular lens (mono-EDOF IOL, xact Mono-EDOF Model ME4) compared with an aspheric monofocal IOL (TECNIS 1-Piece IOL Model ZCB00). Setting: Sites in the United Kingdom, France, and Portugal. Design: Prospective, multicenter, controlled, single-masked, randomized 2:1 (test:control) clinical trial. Methods: Adults 40 years of age or older with bilateral cataracts, expected postoperative refractive astigmatism of ≤1.0 diopter (D) and calculated lens power 18 to 30 D, underwent implantation of either mono-EDOF or aspheric monofocal IOL in both eyes. Primary endpoints assessed at days 120 to 180 included monocular uncorrected distance visual acuity (UDVA) and visual disturbances. Secondary endpoints were monocular uncorrected intermediate visual acuity (UIVA) and monocular distance corrected intermediate visual acuity (DCIVA). Results: 65 patients were randomized; 45 patients (95.2%) with Mono-EDOF and 20 patients (95.2%) with control completed the study. Compared with control, Mono-EDOF had significantly better monocular UDVA (P = .0128), monocular UIVA (P < .001), and monocular DCIVA (P < .001). Monocular and binocular defocus curve measurements confirmed increased depth-of-focus for the Mono-EDOF compared with the control IOL by approximately 0.50 D and 0.75 D, respectively. Contrast sensitivity measured under mesopic conditions with and without glare was similar between groups. Halo or glare was reported by 25.7% and 33.3% of patients in the Mono-EDOF group, respectively, and 22.2% and 25.0%, respectively, in the control group. Conclusions: The xact Mono-EDOF ME4 IOL is a safe and effective alternative to a monofocal IOL. It provides superior intermediate VA compared with an aspheric monofocal IOL without compromising contrast sensitivity or creating unwanted photic phenomena.

Introduction: Phakic intraocular lenses (IOLs) provide excellent visual and refractive outcomes with a high safety profile. This report illustrates a case of a rare episode of severe anterior segment inflammation after iris-claw foldable lens implantation, which required surgical reintervention. Patient and Clinical Findings: A 22-year-old woman was submitted to Artiflex implantation for the correction of myopia. Three months postoperatively, a severe anterior segment inflammation developed with pigment deposition, pupillary membrane formation, and decreased visual acuity in the left eye. Diagnosis, Intervention, and Outcomes: Given the nonresponse to medical treatment (topical and systemic corticosteroid for 3 months), surgical explantation of the IOL with peeling of a pigmentary membrane over the crystalline lens was performed. During a 24-month follow-up period, the patient was monitored to exclude the development of cataract or glaucoma. Afterward, an implantable collamer lens was implanted with an uneventful intraoperative and postoperative period. During the long-term follow-up, no further pigment dispersion, uveitis, or cataract was described. Conclusions: Persistent anterior uveitis with pigmentary membrane formation after iris-claw lens implantation is a rare complication. IOL explantation needs to be considered to prevent further sequelae after severe uveitis when the situation is unresponsive to medical treatment.

Purpose: To evaluate visual, refractive, and topographic outcomes of intracorneal ring segment implantation in relation to the achieved segment depth, using the manual technique. Setting: Ophthalmology Department, Hospital de Braga, Braga, Portugal. Design: Retrospective cohort study. Methods: We obtained 104 eyes of 93 patients with keratoconus submitted to Ferrara intracorneal ring segment (ICRS) implantation, using a manual technique. Subjects were divided into 3 groups according to the achieved depth of implantation: 40% to 70% (Group 1), 70% to 80% (Group 2), and 80% to 100% (Group 3). Visual, refractive, and topographic variables were evaluated at baseline and 6 months. Topographic measurement was performed using Pentacam. Thibos-Horner and Alpins methods were used to analyze the vectorial change of refractive and topographic astigmatism, respectively. Results: We found a significant improvement of uncorrected distance visual acuity and corrected distance visual acuity in all groups at 6 months (P < .005); no differences were observed regarding safety and efficacy indexes in the 3 groups (P > .05). Manifest cylinder and spherical equivalent significantly reduced in all groups (P < .05). Topographic evaluation showed a significant improvement of all parameters in the 3 groups (P < .05). A shallower (Group 1) or deeper (Group 3) implantation was associated with topographic cylinder overcorrection, a higher magnitude of error, and a higher mean centroid postoperative corneal astigmatism. Conclusions: ICRS implantation with the manual technique showed to be equally effective in visual and refractive outcomes despite the depth of implantation; however, shallower or deeper implants were associated with topographic overcorrection and a higher mean centroid postoperative astigmatism, which explain the lower topographic predictability associated with manual surgery for ICRS implantation.

Objective: To compare cross-linking (CXL) plus topography-guided photorefractive keratectomy (t-PRK) and intrastromal corneal ring segments (ICRS) in keratoconus patients, at 12 months of follow-up. Methods: This was a longitudinal, retrospective multi-center study. We included a referred sample of 154 eyes from 149 patients with grade I-III Amsler-Krümeich keratoconus with insufficient corrected-distance visual acuity (CDVA). In group 1 (CXL plus t-PRK, 87 eyes), another possible indication for surgery was evidence of progression. Group 2 (ICRS, 67 eyes) included only eyes with paracentral keratoconus (thinnest point at the inferotemporal quadrant) with coincident axes, and evidence of stabilization was required. A subgroup analysis was performed regarding the disease topographic phenotype. At 12 months postoperatively, visual, refractive, and topographic outcomes were evaluated. Results: Comparison of the outcomes between CXL plus t-PRK (group 1) and ICRS (group 2) showed similar improvements in CDVA (in group 1, CDVA improved 0.18 logMAR, and in group 2 0.12 logMAR, P = .18) and K2 (−2,45 [6.46] D in group 1 and −2.13 [1.67] D in group 2, P = .34) The improvement in cylinder power was greater in group 2 (−2.37 [2.07] D in group 2 versus −1.18 [2.63] D in group 1, P = .003); group 1 had a higher decrease in Kmax (- 3.26 [3.64] versus—1.74 [2.67], P = .001). Conclusions: Both CXL plus t-PRK and ICRS were equally effective in improving CDVA and topographic parameters in a similar group of keratoconus patients at 12 months.

Purpose: To compare visual, refractive, and safety outcomes of posterior chamber Implantable Collamer Lens (ICL) implantation for the correction of myopia according to the preoperative anterior chamber depth (ACD). Methods: Retrospective, comparative study, patients submitted to implantation of myopic posterior-chamber phakic Implantable Collamer Lens (ICL), model V4C/V5, minimum follow-up of 12 months; two groups were created: Group 1 (ACD 2.80 to 2.99 mm) and Group 2 (ACD equal to or greater than 3.00 mm). The parameters evaluated were uncorrected and corrected visual acuity, subjective refraction, efficacy and safety index, predictability, endothelial cell density, central vault, anterior chamber angle and postoperative complications. A total of 558 eyes from 298 patients were evaluated: 111 eyes (19.9%) in group 1 and 447 eyes (80.1%) in group 2. Results: At 12 months, the efficacy index was similar in both groups ( p = 0.264); the safety index was higher in group 1 ( p = 0.031); the mean central Vault was significantly lower in group 1 (212.8 vs 410.6 μm; p < 0.001). Respectively, 93 (83.8%) and 366 (84.1%) eyes were within ±0.50 D of targeted refraction. Anterior chamber angle significantly decreased during follow-up in both groups ( p < 0.001; p < 0.001). Intraocular pressure did not change significantly ( p = 0.310 and p = 0.446, respectively). There were no significant differences in endothelial cell density loss ( p = 0.278) or in the rate of complications observed ( p = 0.733). Conclusions: ICL implantation is an effective and safe procedure in eyes with shallow anterior chambers, with visual and refractive results and complication rates identical to those obtained in deeper anterior chambers.

Purpose: To evaluate the long-term effectiveness, safety, and stability of Ferrara-type intrastromal corneal ring segments (ICRS) by manual surgery implantation in patients with keratoconus. Setting: Ophthalmology Department, Hospital de Braga, Braga, Portugal. Design: Retrospective cohort study. Methods: This study included 124 eyes that had ICRS implantation using the manual technique with a follow-up of 5 years. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refraction, keratometry, aberrometry, and pachymetry maps were evaluated preoperatively and at 6 months, 1 year, and 5 years postoperatively. A secondary analysis of all variables was performed comparing 2 subgroups of patients: a group younger than 30 years and a group of 30 years or older. Results: At 5 years, both mean UDVA and CDVA improved significantly (P < .0001) from a preoperative value of 0.91 ± 0.36 to 0.46 ± 0.32 logMAR and 0.40 ± 0.27 to 0.22 ± 0.20 logMAR, respectively. Spherical equivalent, refractive cylinder, and all topography values significantly decreased postoperatively (P < .0001). No regression was observed in any visual or topographic parameter during the entire follow-up. Regarding the subgroup analysis, both younger and older patients demonstrated similar and stable results from the preoperative to the 5-year visit, except for minimum pachymetry value change over time. Conclusions: Ferrara-type ICRS implantation significantly improved visual acuity, refractive error, and topographic values; the improvement was stable throughout a 5-year follow-up period. This study confirms that ICRS implantation surgery for keratoconus is a stable procedure in a long-term follow-up, regardless of the preoperative patient's age.

Purpose: To evaluate the long-term efficacy and safety of iris-fixated foldable phakic intraocular lenses (pIOLs) for the management of myopia and astigmatism after 6-year follow-up. Setting: Ophthalmology Department, Hospital Braga, Portugal. Design: Retrospective cohort study. Methods: Patients included underwent iris-fixated foldable Artiflex pIOL implantation between January 2010 and December 2013. Follow-up evaluations were performed 6 months postoperatively and every 12 months until 72 months. Preoperative and follow-up data on uncorrected and corrected distance visual acuity (CDVA), manifest refraction, endothelial cell density (ECD), and anterior chamber depth (ACD) were analyzed. Results: A total of 177 eyes of 98 patients with a mean age of 32.33 ± 7.13 years were analyzed. There was a statistically significant improvement in CDVA from 0.09 ± 0.02 logMAR preoperatively to 0.04 ± 0.02 logMAR (P < .0001) at 6 years postoperatively. The spherical equivalent demonstrated a statistically significant improvement from −9.50 ± 2.93 diopters (D) to −0.41 ± 0.45 D at 6 years. At 72 months, the efficacy and safety indexes were 0.94 and 1.15, respectively. A mean loss of 31.77 cells/mm² (1.19%) was observed each year until the sixth year. The overall mean ECD loss after correction for the physiological loss was 3.02% after 6 years. No correlations were observed between the mean ECD loss and the preoperative ACD. Conclusions: The Artiflex pIOL was a safe, effective, and a stable option to correct myopia. A mean ECD loss of 3.02% was observed over 6 years. No pIOL was explanted due to corneal decompensation.

Purpose: To compare the incidence of complications between manual and femtosecond-laser assisted surgery for intrastromal corneal ring segments (ICRS) implantation. Material and methods: This study included keratoconus patients who had ICRS implantation using manual dissection and using the femtosecond laser with a minimum follow-up of 12 months. Uncorrected (UDVA) corrected (CDVA) distance visual acuity (CDVA), refraction, corneal topography and aberrometry, pachymetry map and slit-lamp microscopy were assessed before and after surgery. Results: The study included 265 eyes in the manual group and 111 in the femtosecond laser group. In the manual group, there were complications in 48 eyes (18.11%); while in the femtosecond laser 4 eyes had a complication (3.6%). In the manual group, the most frequent complications were ICRS exchange/adjustment for visual and refractive enhancement (25 eyes; 9.43%) and late ICRS spontaneous extrusion (15 eyes; 5.66%). In the manual group, 81.25% of complications were observed during the first 3 years of surgeon’s experience. Eyes who suffered a complication had preoperatively higher mean refractive (p=0.002) and topographic cylinder (p=0.003) and lower UDVA (p= 0.005) and CDVA (p=0.002). After a second surgical procedure for complication management visual, refractive and topographic outcomes significantly improved. Conclusion: Manual mechanical ICRS surgery shows a higher rate of intra- and postoperative mechanical and refractive complications when compared to femtosecond laser assisted technique. The incidence is specially higher during the surgeon’s first years of implementation of the technique.