[A randomized study of subconjonctival bevacizumab (Avastin®) injection for corneal neovascularization]. / Étude randomisée de l'injection sous-conjonctivale de bévacizumab (Avastin®) dans la néo-vascularisation cornéenne.

PURPOSE: The goal of this phase III, comparative, multicentric, randomized, double-blinded clinical trial was to investigate the superiority of subconjunctival bevacizumab injections versus placebo in the treatment of corneal neovascularization. PATIENTS AND METHODS: We included 38 eyes (38 patients) with corneal neovascularization. Twenty patients received bevacizumab and 18 placebos. Patients received 3 monthly injections of either 5mg (0.2mL) bevacizumab or placebo. The main criteria of success was reduction of the surface area of corneal neovascularization after 3months (M3) versus baseline, as measured using semi-automatic analysis of color photographs. RESULTS: The percentage of neovascularized corneal surface decreased by -8.6%±32.8 with bevacizumab, versus -2.6%±20.8 with placebo (p=0.5284). Four patients were determined to be responders (reduction of more than 30%), 3 in the bevacizumab group and 1 in the placebo group, all with neovascularization of less than 1year duration. When restricting the analysis to neovascularization of less than 1 year duration, the difference approached the threshold for significance (-31.8%±42.4 in the bevacizumab group and -0.9%±23.1 in the placebo group) (p=0.0637), as well as the number of responders (3/6 in the bevacizumab group versus 1/10 in the placebo group) (p=0.1181). No serious adverse event was reported. CONCLUSION: This study shows the efficacy of subconjunctival bevacizumab injection in the reduction of neovascularized corneal surface area versus placebo, but only when the neovascularization has been present less than 1year. Nevertheless, the study did not attain the statistical power to pass the threshold of significance.

[Effect of keratoplasty on the quality of life of keratoconus patients]. / Effet de la kératoplastie sur la qualité de vie des patients atteints de kératocône.

Corneal deformations caused by keratoconus produce high levels of optical aberration (OA). Despite appropriate optical correction, these alter the quality of vision and diminish the patient's quality of life, especially since the affected population is predominantly young and of working age. When thinning is too severe or corneal transparency too impaired, a corneal transplant may be considered. In this study, we compare the quality of life of patients with keratoconus in the early (stages 1 and 2) or advanced (stages 3 and 4) stages of the Krumeich classification, as well as patients who have had keratoconus treated by keratoplasty. Quality of life was assessed using the NEI-VFQ 25 questionnaire, the most widely used for keratoconus. An aberrometric examination (OQAS®; HD Analyser, Visiometrics, Terrassa, Spain) was also performed to assess patients' quality of vision. Our results show that keratoplasty provides an improvement in quality of life compared with advanced-stage keratoconus in the areas of distance (p=0.0083) and near vision (p=0.029) activities. This improvement also applies to Best-Corrected Visual Acuity (BCVA) (p=0.032) and transparency (OSI) (p=0.049). Our study shows that keratoplasty improves corneal transparency, and it is interesting to note that it improves patients' quality of life over the long term.

Biometric and corneal characteristics in marfan syndrome with ectopia lentis.

PURPOSE: To describe the biometric and corneal characteristics of patients with Marfan Syndrome (MFS) and ectopia lentis. STUDY DESIGN: Observational, descriptive, prospective study. Subjects Individuals with MFS with ectopia lentis (EL). METHODS: Fourty-four eyes of 23 patients underwent Scheimpflug analysis using the Pentacam (Oculus, Wetzlar, Germany), axial length (AL) using the IOL master 700 (Carl Zeiss AG, Oberkochen, Germany), endothelial cell count (ECC) using the CEM-350 (NIDEK, Maihama, Japan) and corneal biomechanics evaluation with the Ocular Response Analyzer: ORA (Reichert Ophthalmic Instruments, Buffalo, New York, USA) and Corvis (Oculus, Wetzlar, Germany). Statistical analysis was performed using IBM SPSS Statistics 25.0. RESULTS: The direction of lens subluxation was most frequently supero-nasal 40.9% (18/44). Mean keratometry (Km) was 40.22±1.76 Diopters (D); mean corneal astigmatism was 1.68±0.83 D; total corneal aberrometric root mean square (RMS) was 2.237±0.795µm; higher-order aberrations (HOAs) RMS were 0.576±0.272µm; mean AL was 25.63±3.65mm; mean ECC was 3315±459cell/mm2; mean CBI was 0.13±0.24, mean TBI was 0.31±0.25, mean posterior elevation was 4.3±4.5µm; mean total corneal densitometry was 16.0±2.14 grayscale units (GSU). CONCLUSION: Increased axial length, flatter and thicker corneas with higher regular astigmatism, normal densitometry, normal corneal biomechanical indices and normal posterior elevation were observed in Marfan patients with EL.

[A severe unilateral corneal ectasia in children]. / Une ectasie cornéenne sévère unilatérale de l'enfant.

PURPOSE: We report a case of unilateral Terrien's marginal degeneration in a 14-year-old girl. CLINICAL CASE: Slit-lamp examination of the affected eye revealed 360° circumferential lipid deposits with 6mm of superior limbal distension, superficial neovascularization, a zone of corneal thinning from 3:00 to 9:00 with a zone of corneomalacia at 11:00. The remainder of the cornea was clear, without fluorescein staining or anterior chamber reaction. DISCUSSION: Terrien's marginal degeneration (TMD) is typically known to occur bilaterally in men over the age of 40. Terrien's degeneration must be differentiated from other causes of peripheral corneal thinning; the primary differential diagnosis is Fuchs' marginal keratitis. Other causes of corneal thinning must be ruled out, including Mooren's ulcer. In Terrien's degeneration, there is no central mined edge in the thinning sulcus, the epithelium remains intact, and affected patients do not present with pain. Other differential diagnoses include pellucid marginal degeneration and sulcus degeneration, which are characterized by the absence of lipid infiltrates associated with the central region of the thinning zone, thus distinguishing them from TMD. CONCLUSION: It is important to keep in mind that Terrien's marginal degeneration can occur in children.

[Long-term visual outcomes of Boston type I keratoprosthesis in Canada]. / Résultats à long terme de la kératoprothèse de Boston de type I au Canada.

BACKGROUND/PURPOSE: To evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure. METHODS: Single surgeon retrospective cohort study including 85 eyes of 74 patients who underwent KPro implantation to treat severe ocular surface disease, including limbal stem cell deficiency, postinfectious keratitis, aniridia and chemical burns. Procedures were performed at the Centre hospitalier de l'Université de Montréal from October 2008 to May 2012. All patients with at least 5 years of follow-up were included in the analysis, including eyes with repeated KPro. Main outcome measures were visual acuity (VA), visual failure, defined as a sustained VA worse than the preoperative VA, postoperative complications, and device retention. RESULTS: Mean follow-up was 7.2±1.3 years (±SD). Mean VA was 2.1±0.7 (logarithm of minimal angle resolution) preoperatively and 1.9±1.2 at last follow-up. In total, 2.4% of patients had VA better than 20/200 preoperatively vs. 36.5% at last follow-up. Maintenance of improved postoperative VA was seen in 61.8% of eyes at 7 years. Preoperative factors associated with visual failure were known history of glaucoma (HR=2.7 [1.2 to 5.9], P=0.02) and Stevens-Johnson syndrome (HR=7.3 [2.5 to 21.4], P<0.01). Cumulative 8-year complication rates were 38.8% retroprosthetic membrane formation, 25.9% hypotony, 23.5% new onset glaucoma, 17.6% retinal detachment, 8.2% device extrusion and 5.9% endophthalmitis. The majority (91.8%) of eyes retained the device 8 years after implantation. CONCLUSION: Nearly two-thirds of patients exhibited improved VA 7 years after KPro implantation. Preoperative risk factors for visual failure were known glaucoma and Stevens-Johnson syndrome.

[Donation and harvesting of post-mortem corneas in the mortuary with a view to transplants]. / Don et prélèvements de cornées post-mortem en chambre mortuaire en vue de greffes.

The donation, removal and transplantation of corneas enable patients to improve or regain their sight. This treatment is possible thanks to deceased people who, during their lifetime, consent to or do not object to the donation. The operation is carried out according to a regulated medical-surgical process, initiated and organized by a specially-trained hospital coordinator.

Evaluation of aqueous-deficient and evaporative dry eye cases with confocal microscopy.

INTRODUCTION: Dry eye disease (DED) is an important health problem affecting hundreds of millions of people worldwide. In vivo confocal microscopy (IVCM) is a non-invasive imaging tool that can visualize ocular surface diseases. In this study, we aimed to evaluate corneal structures and inflammatory cells with IVCM in DED patients. MATERIAL AND METHODS: The patients were divided into three subgroups: group 1, consisting of 22 patients with aqueous tear insufficiency; group 2, consisting of 21 patients with evaporative type DED; and group 3, consisting of 20 healthy patients. Imaging was performed with IVCM. The corneal epithelium, nerves, stroma, endothelial and inflammatory cells were compared between groups. RESULTS: There was a significant decrease in corneal epithelial cell density in cases with DED, and there was a significant increase in corneal basal epithelial cell density in the aqueous-deficient type. Keratocyte density was significantly increased in the aqueous-deficient type. A significant decrease in the number and density of sub-basal nerves was found in aqueous-deficient cases, and an increase was found in neural pilling and folding. Dendritic cell density, size, number and area were significantly increased in the aqueous-deficient type. There was also decreased corneal endothelial cell density in DED. CONCLUSION: We evaluated pathological changes in DED on the corneal surface by IVCM. This methodology is valuable in terms of objectively evaluating how the corneal surface is affected in accordance with disease severity and in predicting poor response to treatment.

[High energy proton therapy for extraocular tumors, neurotrophic keratitis and functional consequence: A series of 3 cases]. / Protonthérapie haute énergie des tumeurs extra-oculaires, kératite neurotrophique et conséquence fonctionnelle : une série de 3 cas.

INTRODUCTION: High energy proton therapy (HEP) is a form of radiation therapy using protons for extraocular tumors. Its ballistic properties are theoretically advantageous, but the real impact on the surrounding ocular tissues during cerebral and ENT irradiation is poorly documented. We describe three consecutive patients with corneal damage following such irradiation. MATERIALS/METHODS: Post-proton therapy neurotrophic keratitis (NK) is defined as corneal hypo/anesthesia responsible for an alteration of corneal trophicity and graded according to the Mackie classification, in terms of a prospective ophthalmological follow-up protocol for all patients with extraocular tumors treated with HEP. RESULTS: Among 193 patients treated with HEP between 2018 and 2021 for extraocular tumors, three patients developed severe neurotrophic keratitis, i.e. 1.6% of treated patients. According to the Mackie classification, the three patients showed grade 3 NK less than one year after the conclusion of their HEP. These three patients underwent amniotic membrane grafting. They were placed on autologous serum eye drops. Two of the three patients had to be eviscerated. The dose to the cornea was greater than 50 Gray (Gy)_Relative biological effectiveness (RBE) in the three cases. DISCUSSION: The diagnosis and etiological origin of neurotrophic keratitis are often difficult to establish. In these cases, the imputability of radiation therapy, proton therapy in our cases, in the development of neurotrophic keratitis was plausible based on the dosimetry of the patients, all of whom had anterior tumors with a poor prognosis requiring high tumoricidal doses. CONCLUSION: Further studies to establish the impact of proton therapy on corneal sensitivity are necessary. However, this feedback and the multidisciplinary management of tumors can help to limit the risk of some complications of radiation therapy. Early diagnosis allows for appropriate management and could possibly minimize the anatomical and functional ocular complications of neurotrophic keratitis.

Comparison of central corneal thickness measurements using three different imaging devices.

PURPOSE: The purpose of this study was to compare central corneal thickness (CCT) values and evaluate the agreement obtained with three different devices in healthy eyes. METHODS: A total of 120 eyes of 60 healthy individuals (36 men and 24 women) were enrolled in this retrospective study. CCT measurements were performed using an optical biometer (AL-Scan), spectral-domain optical coherence tomography (SD-OCT) (Topcon 3D) and ultrasonic pachymetry (UP) (Accupach VI), and the results were compared. Bland-Altman analysis was used to quantify the agreement between methods. MAIN RESULTS: The mean patient age was 28±5.73years (18-40years). The mean CCT values obtained by AL-Scan, UP, and SD-OCT were 532.4µm±29.7, 549µm±30.4, and 547µm±30.6, respectively. The mean differences in CCT were 15.30±9.52µm between AL-Scan and OCT (P<0.01), 17.15±8.42µm between AL-Scan and UP (P<0.01), and 1.85± 8.78µm between UP and OCT (P=0.067). All three methods of CCT measurement were closely correlated with each other. CONCLUSION: The present study results suggest that, despite good agreement between the three devices, AL-Scan significantly underestimated CCT compared to UP and OCT. Therefore, clinicians should be aware that different results can be obtained using different devices for CCT measurements. It would be a better approach not to use them as interchangeable in clinical practice. CCT examination and follow-up should be performed using the same device, especially for patients who will undergo refractive surgery.

Deep anterior lamellar keratoplasty (DALK) interface neovascularization: An unusual complication.

We present a case of a 31-year-old male with a past ocular history significant for keratoconus in both eyes, who underwent Deep Anterior Lamellar Keratoplasty (DALK) for his left eye and experienced graft-host interface neovascularization and interface hemorrhage as a complication. He was treated initially with removal of sutures and optimization of the ocular surface followed by subconjunctival bevacizumab, which subsequently improved his hemorrhage and neovascularization.

[Corneal epithelial biomechanics: Resistance to stress and role in healing and remodeling]. / Biomécanique de l'épithélium cornéen : résistance au stress et implications dans la cicatrisation et le remodelage.

The corneal epithelium is one of the first tissue barriers of the eye against the environment. In recent years, many studies provided better knowledge of its healing, its behavior and its essential role in the optical system of the eye. At the crossroads of basic science and clinical medicine, the study of the mechanical stresses applied to the cornea makes it possible to learn the behavior of epithelial cells and better understand ocular surface disease. We describe herein the current knowledge about the adhesion systems of the corneal epithelium and their resistance to mechanical stress. We will also describe the involvement of these mechanisms in corneal healing and their role in epithelial dynamics. Adhesion molecules of the epithelial cells, especially hemidesmosomes, allow the tissue cohesion required to maintain the integrity of the corneal epithelium against the shearing forces of the eyelids as well as external forces. Their regeneration after a corneal injury is mandatory for the restoration of a healthy epithelium. Mechanotransduction plays a significant role in regulating epithelial cell behavior, and the study of the epithelium's response to mechanical forces helps to better understand the evolution of epithelial profiles after refractive surgery. A better understanding of corneal epithelial biomechanics could also help improve future therapies, particularly in the field of tissue engineering.

Corneal neurotization in the management of neurotrophic keratopathy: A review of the literature.

Neurotrophic keratopathy (NK) is a rare degenerative disease in which damage to the corneal nerves leads to corneal hypoesthesia or anesthesia. Neurotrophic corneal ulcers are notoriously difficult to treat and can lead to blindness. Corneal neurotization (CN) is a recent surgical technique aimed at restoring corneal sensation and may offer a definitive treatment in the wake of NK. Herein, we review the surgical techniques utilized in direct and indirect CN. Technical considerations, outcomes, current limitations and future perspectives are also discussed. This article highlights the key points of this promising procedure and biological aspects that will help provide the best treatment options for patients with severe NK.

[Virological diagnosis of anterior herpetic ocular disease on tear sample: A simple and non-invasive technique]. / Diagnostic virologique des atteintes oculaires herpétiques antérieures sur prélèvement lacrymal : une technique simple et non invasive.

INTRODUCTION: Virological diagnosis of anterior ocular herpetic disease (AOHD) is essential for the management of these often-chronic pathologies that may require long-term therapy. PCR has become the gold standard, but the type of sampling (tears, corneal scraping, aqueous tap) has not been standardized. In this study, we studied the technique of tear sampling for the diagnosis of AOHD. MATERIALS AND METHOD: We retrospectively analyzed the medical files of patients with a positive tear sample (Schirmer strip) for herpes simplex 1 virus (HSV-1) in the Department of Ophthalmology of Paris-Saclay Bicêtre Hospital between January 2018 and December 2020. We studied the clinical and virological characteristics (viral loads) of these cases of proven AOHD. RESULTS: Thirty-six samples (33 patients) were included: 12 epithelial keratitis, 9 stromal HSK with ulceration, 5 uveitis, 4 stromal HSK without ulceration, 3 blepharitis, 1 endothelial HSK, 1 neurotrophic keratitis, and 1 conjunctivitis. The mean viral load was 3.9×105 copies/mL. Viral load was higher in cases of corneal ulceration (5.2×105±9.4×105 versus 1.2×102±1.7×102 copies/mL, P<1×10-4). There was no significant difference between primary episodes and relapses. CONCLUSION: Tear sampling using Schirmer strips is a simple, non-invasive method that can be useful for the virological diagnosis of various clinical forms of AOHD.

Application of data mining algorithms to study data trends for corneal transplantation.

PURPOSE: To utilize data mining for analysis of corneal transplantations (CT) in Florida from 2005-2014, segmented by demographics, geography, and transplantation technique. METHODS: A retrospective, database study was performed utilizing data queried from the Healthcare and Cost Utilization Project using Current Procedural Terminology codes for lamellar keratoplasty (ALK), endothelial keratoplasty (EK), and penetrating keratoplasty (PKP). Payer status, ethnic group, age, gender, and geography (urban versus rural) was extracted from each surgical encounter and reconfigured to provide a "clean", congruous dataset for statistical analysis. This Institutional Review Board-approved study did not utilize identifiable patient information; thus, individual informed consent was not required. RESULTS: From 2005-2014, CT (n=28,607) represented less than 1% of the total ambulatory surgeries (n=12,695,932) performed in Florida. EK volume increased while PKP and ALK volume decreased, year-over-year. Statistical significance was found between transplantation technique by sex (P<0.001) and ethnic group (P<0.001). The largest sex discrepancy was EK (59% female, 41% male). White patients underwent relatively fewer PKP than EK (71% vs. 83% of totals), while Black patients underwent relatively more PKP than EK (14% vs 6% of totals). Statistical significance was found between techniques by payer (P<0.001). Medicare was the most common payer for all techniques, but ALK and PKP had higher percentages of private insurance and self-pay. No statistical significance was found between techniques by geographic location. Corneal edema (22.4%), endothelial dystrophy (17.5%), and bullous keratopathy (10.9%) were erroneously coded as indications for ALK. Corneal scars (2.5%) and corneal opacity (1.7%) were erroneously coded as indications for EK. CONCLUSIONS: CT rates in Florida appear to overrepresent the female sex and underrepresent ethnic minorities, with propensities between PKP and African Americans, EK and female patients, and EK and Medicare reimbursement. Our study further confirms the utility of data mining for providing efficient, detailed, and practical insights into ophthalmology procedures, while highlighting the intrinsic challenges of large datasets.

[Penetrating keratoplasty]. / Kératoplastie transfixiante.

Penetrating keratoplasty is a tissue transplant commonly performed around the world. For over a century, penetrating keratoplasty has been the standard method of treatment for many corneal diseases causing visual impairment. Recently, lamellar anterior keratoplasty (LAK) or lamellar endothelial (LEK) have become preferable options, resulting in fewer complications and faster functional rehabilitation. While penetrating keratoplasty is less frequently indicated, in favor of these lamellar grafts, it has not necessarily become obsolete, and its use remains appropriate for its chosen indications. Functional results are good if the indication for surgery is properly assessed, therapeutic precautions are taken in view of complications, and follow-up aims to improve initial refractive results as needed.

Evaluation of the agreement of optical biometry and Scheimpflug corneal topography with different axial lengths.

PURPOSE: To compare anterior segment parameters evaluated with optical low coherence reflectometry and combined Scheimpflug-Placido disc topography in eyes with different axial lengths. METHODS: Deux cent quatre patients were divided into 3 groups according to their axial lengths. Central corneal thickness (CCT), anterior chamber depth (AD), mean keratometry value (K mean) and white-to-white distances (WTW) obtained from both devices were compared. All measurements were performed 3 times and averaged. RESULTS: In group 1, a significant difference was detected between the two devices for CCT, WTW and Kmean measurements (P<0.001, P<0.001, p:0.005 respectively). In group 2, a significant difference was detected between the two devices for WTW measurement (P<0.001). In group 3, a significant difference was detected between the two devices for CCT and WTW measurement (P<0.001, P<0.001 respectively). In the Bland-Altman analysis, there was no match for Kmean obtained with both devices in group 1. In group 2, there was no agreement for AD obtained with both devices. In group 3, there was no match for AD, WTW or Kmean values obtained with both devices. CONCLUSION: Some anterior segment parameters are not suitable for interchangeability in eyes with different axial lengths evaluated by Lenstar and Sirius anterior segment imaging systems. When planning critical surgery and treatment, more attention should be paid to measurements in eyes of different axial lengths.

[Outcomes of cataract surgery in patients with Fuchs endothelial corneal dystrophy]. / Chirurgie de cataracte seule chez le patient porteur d'une dystrophie endothéliale de Fuchs.

PURPOSE: While endothelial keratoplasty has become the standard treatment for Fuchs dystrophy, the strategy for first-line surgery in patients with associated cataract is still debated. The purpose of this study was to evaluate the surgical outcomes of eyes with Fuchs endothelial corneal dystrophy (FECD) undergoing phacoemulsification alone, to ascertain preoperative factors that predict the need for endothelial keratoplasty (EK). METHODS: Single-center retrospective study. Cataract surgery alone was performed in 64 eyes of 50 patients with FECD. This decision was made if the patient did not have morning blur, the central corneal thickness (CCT) was below 630 microns, and endothelial cells were visible in the periphery. RESULTS: Mean follow-up was 21 months (range 5-55 months). The mean preoperative CCT was 571±43µm. 6 months after surgery, it was 584±52µm (P=0.12). During follow-up, 14 eyes (22%) required an EK because of poor visual outcome after cataract surgery alone. Mean pre-operative CCT of these eyes (595±23µm) was significantly higher than eyes that did not require EK during follow-up (564±45µm, P=0.022). Over 570 microns, 34% of eyes required an endothelial keratoplasty after the cataract surgery alone. CONCLUSIONS: CCT below 630µm associated with the absence of morning blur are preoperative criteria allowing 78.1% eyes with FECD to obtain good visual outcomes after cataract surgery alone. In these eyes, EK can therefore be avoided while ensuring good results.

The opioid peptide biphalin modulates human corneal epithelial wound healing in vitro.

PURPOSE: Analgesic drugs, including nonselective opioids and non-steroidal anti-inflammatory drugs, should be used with great precautions to relieve pain after trauma to the corneal epithelium because of their unfavorable effects on wound healing. Biphalin is a synthetic opioid peptide that has been demonstrated to possess a strong analgesic effect on rodents. The purpose of this study is to investigate the effects of biphalin on human corneal epithelial wound healing. METHODS: An immortalized human corneal epithelial cell (HCEC) culture was used to analyze the effects of biphalin on wound healing. The toxicity of biphalin at various concentrations was measured by the MTT assay. The effects of 1µM and 10µM biphalin on wound closure, cell migration and proliferation were tested in an in vitro scratch assay of HCECs. Naloxone, a non-selective competitive opioid receptor antagonist, was also used to inhibit the effects of biphalin in all experiments. RESULTS: Biphalin did not cause any toxic effect on HCECs at concentrations lower than 100µM at various incubation time points. Biphalin significantly increased wound healing at 1µM concentration in an in vitro scratch assay of HCECs (P<0.05). It also significantly increased migration of HCECs (P<0.01). There was no significant difference between the biphalin and control groups of HCECs in the Ki67 proliferation assay. CONCLUSION: Biphalin, which is a synthetic opioid peptide, promotes corneal epithelial wound healing by increasing cell migration. This role should be evaluated in further in vivo and clinical studies.

The role of posterior corneal power in 21st century biometry: A review.

PURPOSE: Intraocular lens (IOL) calculation and biometry have evolved significantly in recent decades. However, present outcomes are still suboptimal. Our objective is to summarize the results reported in the literature with regard to a new variable, the value of the relationship between anterior and posterior corneal curvature in the biometric calculation of IOL power. METHODS: We have created a narrative revision of the existing evidence regarding the posterior to anterior corneal curvature ratio in IOL calculation. RESULTS: The corneal posterior/anterior ratio (P/A ratio), also called Gullstrand ratio, has a standard deviation of 2.4% in normal people, hence causing a possible IOL power miscalculation error of up to 0.75 diopters (D). This error is magnified in pathological corneas or in those with previous refractive surgery. Including the P/A ratio in the IOL formula reduces errors in the calculation of IOL power. CONCLUSIONS: Measurement of the posterior corneal surface should be recommended prior to IOL calculation, given the demonstrated results regarding the P/A ratio for IOL power calculation. Regarding toric IOL calculation, we suggest incorporation of all internal astigmatic vectors, for instance, posterior corneal surface, IOL tilt induced toricity, and retinal astigmatism. All of these factors may improve surgical outcomes.

[Regression and ablation profiles in corneal refractive surgery]. / Régression et profils d'ablation en chirurgie réfractive cornéenne.

Regression after corneal refractive surgery is a complex phenomenon which seems inevitable. The choice of surgical technique has very little influence on regression for low myopia or myopic astigmatism. However, LASIK and SMILE are the two techniques of choice in the correction of high myopia. LASIK is also better for the correction of hyperopia, hyperopic astigmatism and mixed astigmatism. Intraoperatively, the choice of a wide optical zone and adherence to a thick residual stromal bed provide stability. Regression may also be reduced by modulating anti-inflammatory therapy, treating dry eye, and using mitomycin C in PKR. In all cases, obtaining keratometry during patient follow-up helps to identify the cause of the regression. The objective of this review is to synthesize recent data from the literature on regression in refractive surgery as a function of the ablation profiles used.