Case Report: Role of Anterior Segment Optical Coherence Tomography for Managing Failed Endothelial Keratoplasty Graft.

SIGNIFICANCE: Some patients show poor visual outcomes after Descemet stripping automated endothelial keratoplasty. In such cases, secondary Descemet membrane endothelial keratoplasty can be performed to achieve complete visual recovery. Anterior segment optical coherence tomography (AS-OCT) is a valuable tool for the follow-up of posterior lamellar keratoplasty outcomes and complications. PURPOSE: This study aimed to report the clinical outcome of secondary Descemet membrane endothelial keratoplasty for managing poor visual results in a patient with graft failure after a previous Descemet stripping automated endothelial keratoplasty, highlighting the importance of AS-OCT in the follow-up of endothelial keratoplasty. CASE REPORT: A 38-year-old woman with high myopia underwent Descemet stripping automated endothelial keratoplasty for bullous keratopathy after explantation of an angle-supported phakic intraocular lens. Two years after keratoplasty, the patient experienced poor visual acuity (counting fingers), and significant corneal edema was observed on clinical examination hindering visualization of the anterior chamber structures. Anterior segment optical coherence tomography showed a failed and thickened graft adhering well to the recipient cornea in an anterior chamber without other comorbidities. Therefore, the graft was removed and replaced with a Descemet membrane endothelial keratoplasty graft without any complications. One year later, the clinical outcome was evaluated by comparing the pre-operative and post-operative best-corrected visual acuity, biomicroscopy findings, endothelial cell density, and corneal central thickness. CONCLUSIONS: Anterior segment optical coherence tomography is an important tool when deciding on the surgical technique to be applied and for the post-surgical monitoring of endothelial corneal grafts. This case demonstrates the successful management of Descemet stripping automated endothelial keratoplasty graft failure with Descemet membrane endothelial keratoplasty graft, highlighting the importance of AS-OCT in detecting complications such as graft dislocation and primary graft failure. In addition, corneal thickness measured using AS-OCT serves as a critical predictor of graft failure, as observed in this case.

Refractive changes and visual quality in patients with corneal edema after cataract surgery.

BACKGROUND: To assess visual quality and stabilization of refractive changes in corneal edema patients after cataract surgery, using visual acuity (VA) and contrast sensitivity measurements. METHODS: Sixty-one eyes were analysed, twenty-three with and thirty-eight without corneal edema. Uncorrected and corrected distance VA (UDVA and CDVA) were determined with an EDTRS chart, the contrast sensitivity function (CSF) under photopic and mesopic illumination conditions with a CVS-1000e chart, clinical refraction, and corneal topography. Measurements were taken preoperatively, 1-2 days, 1 and 3-months after surgery. Clinical refraction was converted to vector notation (M, J0, J45) and SPSS v26.0 was used for data analysis. RESULTS: An improvement of VA was observed through the postoperative period; changes between visits were significant for CDVA in both groups and for UDVA in the edema sample. Significant astigmatic changes (J0,J45) between visits were not observed, but M values showed a hyperopic tendency in the edema group and a myopic shift in the control group that did not change between visits, with statistically significant differences between groups. Controls had significantly better contrast sensitivity at high spatial frequencies. Under mesopic conditions, global contrast sensitivity losses were observed in the edema group, which improved between visits in the middle frequency range. CONCLUSION: Corneal edema patients had a significant reduction of CDVA, and frequency-selective sensitivity losses that evidence a visual quality loss. Clinical refraction may improve visual quality, but in edema patients these losses are related to corneal changes, which did not change at three months after surgery.

The Link between Anterior Scleral Thickness, Corneal Biomechanical Response, and Ocular Parameters.

INTRODUCTION: This study aimed to assess anterior scleral thickness (AST) across diverse scleral meridians and to evaluate the relationship with corneal biomechanical response and several ocular parameters. METHODS: This prospective nonrandomized study comprised 50 eyes of 50 patients (mean age, 29.02 ± 9.48 years). AST was measured meridionally at three scleral locations (1, 2, and 3 mm posterior to the scleral spur) using swept-source optical coherence tomography. A multivariate model was created to associate AST with several ocular parameters. Principal component analysis (PCA) was used to reduce linearly the dimensionality of seven biomechanical input metrics to two significant components, C1 and C2. Two multivariate analyses were performed to associate C1 and C2 with AST and ocular parameters. RESULTS: AST was thickest in the inferior (581 ± 52 µm) and thinnest in the superior meridian (441 ± 42 µm) when compared to all meridians (p < 0.001) and similar in the nasal (529 ± 53 µm) and temporal (511 ± 59 µm) meridians (p > 0.05). The sclera exhibited the thinnest point 2 mm posterior to the scleral spur (p < 0.001). The AST was significantly linked with axial length, central corneal thickness, and intraocular pressure (p < 0.001). The PCA showed that C1 accounts for 53.84%, whereas C2 for the 16.51% of the total variance in the original variables. The C1 model was significantly associated with AST along all meridians (p < 0.001). The partial correlation was moderate in the nasal (r = -0.36, p < 0.001) and inferior (r = -0.26, p = 0.004) meridians, whereas weak in the temporal (r = -0.14, p = 0.05) and superior (r = -0.15, p = 0.05) meridians. CONCLUSIONS: The relationship between the new biomechanical component and the AST provides the first evidence of the association of AST with the corneal response parameters which should be considered in corneal response interpretation. Tissue thickness varied significantly among meridians supporting the asymmetrical expansion of the ocular globe. The AST was associated with several ocular parameters.

Case Report: Role of Anterior Segment Optical Coherence Tomography in Late-onset Capsular Block Syndrome.

SIGNIFICANCE: We report the use of anterior segment optical coherence tomography (AS-OCT) as a valuable tool for capsular block syndrome diagnosis and follow-up. PURPOSE: The purposes of this study are to report a case of late-onset capsular block syndrome or lacteocrumenasia and to describe differential diagnosis with other more common phacoemulsification complications such as intraocular lens (IOL) or posterior capsule opacification. CASE REPORT: We report the case of a 56-year-old man with a clinical history of cataract surgery in his left eye. Five years after cataract surgery, he complained of blurred vision and was referred for IOL removal to our hospital. After careful slit-lamp examination, we found that the lens was clear, and opacity belonged to the accumulation of a whitish material in the capsular bag behind the lens. AS-OCT gave the definite diagnosis of capsular block syndrome. Intraocular lens removal had been wrongly indicated, and we treated our patient by YAG laser posterior capsulotomy. AS-OCT confirmed the absence of a further accumulated material, so no other interventions were needed. After treatment, best-corrected visual acuity improved from 0.48 to 0.1 logMAR. CONCLUSIONS: Capsular block syndrome is a rare late-onset complication of cataract surgery causing a deep visual acuity decay. A precise slit-lamp examination and AS-OCT, together, avoid misdiagnosis and unnecessary surgical treatment, which may be needed in case of IOL opacity or fibrotic-like lacteocrumenasia. AS-OCT also helps in determining the treatment outcome. Immediate best-corrected visual acuity improvement is reached after a successful intervention.

Fitting Scleral Lenses Less Than 15 mm in Diameter: A Review of the Literature.

OBJECTIVE: To perform a comprehensive review of the current and historical scientific literature on fitting small scleral lenses (diameter <15 mm) and clarifying their advantages and disadvantages, in addition to their clinical applications. METHODS: The literature search was performed through PubMed from MEDLINE. RESULTS: Eleven studies of case series (258 eyes) were found. Indications were similar to those of larger scleral lenses, 74% for corneal irregularities (mainly keratoconus), whereas 26% for ocular surface diseases. In the studies on cases of irregular corneas, visual acuity improved significantly regarding the values before and after fitting the lenses (mean, 0.4-0.03 logMar, respectively). Moreover, no significant adverse effects on the ocular surface were reported, and most studies reported over 10 hr (or thereabouts) of daily wear without removing the lenses. A better corneal physiology and visual quality, easier fitting procedure and lens handling, and prolonged hours of wear are proposed as significant advantages over larger scleral lenses. CONCLUSION: Small scleral lenses may be a safe and healthy alternative option to treat corneal irregularities and ocular surface diseases. These lenses can be fitted when it is necessary to improve visual quality and corneal physiology, when discomfort with other contact lenses is experienced, or when patients have difficulty handling larger diameters of scleral lenses. However, fitting these lenses is not suggested in severe cases or when it is not a reasonable clinical option.

Locking Y Lateral Canthopexy as a Treatment for Dry Eye Disease Caused by Eyelid Malposition.

PURPOSE: The signs and symptoms of dry eye disease (DED) can affect the quality of life of patients. This study analyzes whether locking Y lateral canthopexy improves patients' quality of life and in what way it does so (based on the ocular surface disease index questionnaire) and DED signs (measured by the fluorescein breakup time, tear osmolarity, Schirmer test, and corneal staining) in patients with DED caused by a eyelid malposition or impaired blink dynamics. METHODS: This was a case-control study. Forty eyes of 20 patients with DED and lateral canthal disinsertion examined at the University Hospital La Ribera during a 1-year period from November 2016 to November 2017. The 40 eyes were divided into 2 groups: Group 1 eyes that underwent locking Y lateral canthopexy (i.e., a plication of the superficial lateral canthal tendon to the lateral orbital rim periosteum); and group 2 eyes that underwent observational treatment, without surgery. Symptoms and signs in OU were recorded separately at baseline and 1 month after surgery. RESULTS: One month after surgery, the ocular surface disease index reduced in group 1 eyes when compared with those of group 2 (p = 0.001), fluorescein breakup time showed an improvement in the operated eyes (group 1) (p < 0.001) and corneal staining was reduced in group 1 after surgery (p = 0.012). The osmolarity results did not change when compared with eyes from group 2 (p < 0.001). CONCLUSIONS: Locking Y lateral canthopexy is an effective surgical technique for treating patients with evaporative dry eye caused by a lateral canthal tendón disinsertion by restoring proper eyelid closure and improving blinking dynamics. It improves DED signs and symptoms, thereby enhancing the quality of life of patients.

Which are the best parameters to obtain proteins and malondialdehyde from a tear sample?

Predictive, preventive and personalized medicine (PPPM) is a current concept in healthcare based on the analysis of biomarkers through non-invasive methods. Biomarkers for inflammation and oxidative stress are especially used for screening. Quantification of tear total protein content is important to identify potential, specific biomarkers, such as malondialdehyde concerning oxidative stress. The Schirmer strip test is an accessible and simple method for tear analysis. However, it is limited by the low concentration of biomarkers in the human tear. In this preliminary study, different procedures were compared for the extraction of tear proteins and malondialdehyde. Schirmer strips were used to obtain tears from healthy subjects. Ionic strength and surfactant agents were assessed, as well as different centrifugation parameters. Finally, several volumes of n-butanol on the process of malondialdehyde extraction were evaluated. The results showed that ionic strength strongly influences the extraction process, although most studies have suggested that surfactant agents are the most relevant factor; the most efficient results were obtained using a 2 M solution of NaCl in phosphate buffered saline. Regarding centrifugation, leaving the Schirmer strip tip left hanging outside the tube cap and using 1000 rpm was the best option, which is a lower centrifugation speed than the usually reported on literature. Moreover, 250 µL was the optimal n-butanol volume for malondialdehyde extraction. The importance of this study relies on the increasing relevance of the biomarkers in the field of PPPM and the need of a standardized method to extract biomarkers from the tears, to optimise its use.

Impact of Corneoscleral Contact Lens Usage on Corneal Biomechanical Parameters in Keratoconic Eyes.

OBJECTIVE: To analyze the changes in corneal biomechanical parameters of keratoconic eyes with and without intracorneal ring segment (ICRS) implants after 1 year of corneoscleral contact lens (CScL) wear. METHODS: Seventy-four eyes of 74 patients were divided into three groups: healthy subjects (29 eyes, control group), and 2 groups of subjects with keratoconic eyes (one group of 20 eyes with ICRS implants and one of 25 eyes without them), which were fitted with CScL. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated before fitting CScL and after 1 year of CScL wear. In addition, endothelial cell count (ECC) and central corneal thickness (CCT) were also recorded. RESULTS: Corneal biomechanical parameters were lower in keratoconic corneas than in healthy corneas. Keratoconic eyes with ICRS implants had lower values than eyes without them for CH (mean±SD, 8.09±1.29 vs. 8.63±1.5 mm Hg, respectively, P=0.120), CRF (6.99±1.38 vs. 8.37±1.52 mm Hg, respectively, P=0.03), and also for CCT and ECC. Data for IOPcc were similar in all groups. After 1-year wearing CScL, no statistically significant differences in corneal biomechanical parameters were registered in any of the groups (all P>0.05), although slight differences (0.13-0.27 mm Hg) were found. CONCLUSION: The viscoelasticity properties of the cornea did not change significantly when wearing corneoscleral contact lenses for 1 year, and therefore, these lenses seem to be safe and healthy and are a reasonable alternative option for keratoconus management.

Comparison of the Ultraviolet Light Filtering across Different Intraocular Lenses.

SIGNIFICANCE: We have analyzed the ultraviolet transmittance of some commercial intraocular lenses (IOLs). The results show differences of wavelength cutoff among them. PURPOSE: The purpose of this study was to measure and compare the ultraviolet light transmittance of different IOLs made out of acrylic hydrophobic, hydrophilic, and hydrophilic with hydrophobic surface materials from different manufacturers. METHODS: The spectral transmission curves of eight monofocal IOLs with the same dioptric power of +20.0 diopters were measured using a PerkinElmer Lambda 35 ultraviolet/visible spectrometer. Two IOLs of each type were tested three times. The ultraviolet cutoff wavelength at 10% transmission and the mean values were calculated. RESULTS: All lenses prevented transmission of ultraviolet C (200 to 280 nm) and B radiation (280 to 315 nm). However, not all IOLs provided the same filtering properties in ultraviolet A (315 to 380 nm). Within the ultraviolet A range, the ultraviolet radiation cutoff wavelength of 10% ranges from approximately 360 to 400 nm. HOYA iSert 250 provided a cutoff wavelength of 398.4 nm; AcrySof SA60AT, 396.2 nm; AcrySof SA60WF, 395.7 nm; CT Asphina 404, 378.34 nm; Tecnis ZCB00, 377.70 nm; CT Lucia 607P, 379 nm; C-Flex 570C, 377 nm; and enVista MX60, 360 nm. CONCLUSIONS: Intraocular lenses of different materials and manufacturers have different ultraviolet transmission characteristics. AcrySof (SA60AT and SA60WF) and HOYA iSert 250 provided the highest ultraviolet radiation transmission; the cutoff wavelength of 10% is close to 400 nm. In contrast, enVista IOL showed the lowest ultraviolet radiation cutoff.

Corneal Biomechanical Parameters With Corneoscleral Contact Lenses in Post-Laser In Situ Keratomileusis Eyes.

OBJECTIVE: To evaluate corneal biomechanical parameters wearing corneoscleral contact lenses (CScL) in patients with irregular corneas after laser in situ keratomileusis (LASIK). METHODS: Data from patients fitted with CScL because of corneal surface irregularities after complicated LASIK surgery were selected by two eye clinics. Previously and after 1 year of CScL fitting, corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and central corneal thickness were evaluated. In addition, visual acuity, subjective comfort, and wearing time CScL were reported. RESULTS: The study comprised 27 eyes. Statistically significant differences were found in visual acuity between the best spectacle-corrected vision and after CScL fitting [mean±SD, 0.16±0.03 logarithm of the minimum angle of resolution (logMAR) and 0.01±0.06 logMAR, respectively; P<0.001]. In addition, the patients reported high subjective comfort ratings (22 eyes were comfortable or very comfortable) and prolonged usage times (mean±SD, 12.67±1.98 hr of continuous wear a day). Statistically significant differences were found in the CRF between before CScL fitting and after 1 year of CScL wear (mean±SD, 7.57±0.87 and 7.68±0.84 mm Hg, respectively; P=0.015). Central corneal thickness, CH, and IOPcc showed slight differences after 1 year of CScL wear (1.78 µm, 0.04 and 0.21 mm Hg, respectively). CONCLUSION: Corneal biomechanical parameters increased slightly, although significantly for CRF, apparently without adverse clinical effects in post-LASIK eyes with irregular corneas after wearing CScL for 1 year.

Post-LASIK Visual Quality With a Corneoscleral Contact Lens to Treat Irregular Corneas.

OBJECTIVE: To evaluate the visual quality results of fitting a corneoscleral contact lens with multiaspheric geometry design (MAGD CScL) in subjects with irregular corneas after laser-assisted in situ keratomileusis (LASIK) surgery. METHODS: From a database of patients evaluated for scleral contact lenses, we identified those with irregular corneas and visual problems after they underwent LASIK surgery for correcting myopia. They manifested unsatisfactory visual quality with their current contact lenses or glasses. Therefore, a MAGD CScL was fitted and monitored according to standardized fitting methodology. A diagnostic trial set was used in the fitting process. Visual acuity (VA), subjective visual quality (SVQ), and ocular aberrations were evaluated. A new re-evaluation of these parameters was performed after 1 year wearing MAGD CScL. RESULTS: Eighteen eyes of 18 patients (10 male and 8 female) with irregular cornea after LASIK surgery participated in this study; their ages ranged from 27 to 39 years (mean±SD, 32.6±3.8 years). All patients showed good fitting characteristics: optimal values were seen for lens position and lens movement. Statistically significant differences were found between before and after fitting MAGD CScL in the VA (mean±SD, 0.14±0.03 logMAR and 0.01±0.06 logMAR, respectively; P<0.001); ocular aberrations of second-order, coma, spherical; and the total higher-order aberrations (HOAs) (all P<0.001). The total HOAs decreased by approximately 78% to normal levels after fitting MAGD CScL. In addition, SVQ was also significantly improved after fitting MAGD CScL (16 eyes were favorable or very favorable). After 1 year wearing MAGD CScL, no statistically significant differences were found in the total HOAs and VA in regard to the initial fitting. CONCLUSIONS: Corneoscleral contact lens with multiaspheric geometry design is proposed as an effective procedure, providing a good VA and an optimal visual quality on irregular corneas after LASIK surgery in myopic subjects.

A rapid method for measuring intraocular lens power in vitro with a focimeter.

In this paper we describe a new method for measuring the intraocular lens (IOL) power using a focimeter, a negative ophthalmic lens and a saline solution (0.9% NaCl). To test this we measured the power of 58 different IOLs and we compared them with the power stated by the manufacturer. Despite the limitations, the results show a good correlation.

Image quality comparison of two multifocal IOLs: influence of the pupil.

PURPOSE: To evaluate the effect of pupil size on image quality of a sectorial multifocal intraocular lens (IOL), the Lentis Mplus (Oculentis GmbH, Berlin, Germany), and the Acri.LISA IOL (Carl Zeiss Meditec, Jena, Germany). METHODS: The authors measured the MTFs of the Lentis Mplus LS-312 IOL and the Acri.LISA 366D IOL with three different sizes of pupil diameters: 3, 4, and 5 mm. The MTF was calculated from the cross-line spread function recorded with the OPAL Vector System (Image Science Ltd., Oxford, UK) by using fast Fourier-transform techniques. RESULTS: In distance focus, the image quality provided by the Lentis Mplus IOL was better than that of the Acri. LISA IOL with all pupil diameters. In near focus, the MTF of the Acri.LISA IOL was better with a 3-mm pupil, but poor with larger pupils. The aberration effect was equal in both IOLs in distance focus, but in near focus and with a 3-mm pupil, the Acri.LISA IOL was less affected by the aberration than the Lentis Mplus IOL. CONCLUSION: The Lentis Mplus IOL provides better distance image quality than the Acri.LISA IOL, whereas the near image quality of the Acri.LISA IOL is better with small-pupil diameter. The sectorial design makes this IOL more suitable for patients with a pupil diameter greater than 3 mm.

Comparative study of the direct closure of surgical incision for external dacryocystorhinostomy using 6-0 Prolene versus Dermabond ®.

PURPOSE: In this study, we aimed to compare closure of the incision for external dacryocystorhinostomy (ext-DCR) by suturing with 6-0 Prolene versus closure with 2-octyl cyanoacrylate and assess the results in terms of the aesthetic and functional aspects of the scar, operating time, postoperative symptoms and complications, and the economic cost of the two techniques. METHODS: Sixty-three patients with distal lacrimal obstruction and indication of ext-DCR were initially enrolled in a longitudinal prospective cohort study. Patients underwent ophthalmologic evaluations including lacrimal probing, external examination with photograph, measurement of the surgical wound, timing the cutaneous closure phase of the surgery, recording postoperative wound pain using visual analog scale (VAS), and recording the patient's and clinician's subjective satisfaction with the scar using Patient and Observer Scar Assessment Scale (POSAS) at 6 months postsurgery. The 63 eyes were divided into two groups: the wounds in group 1 were closed with 6-0 Prolene using continuous locking suture and the wounds in group 2 were closed with 2-octyl cyanoacrylate. RESULTS: There was no difference in baseline characteristics (age, sex, and race), and no statistically significant differences were found in wound length, POSAS score, VAS score, or serious complications of the wound between the two groups. There were differences in surgery time and economic cost for group 2 compared to group 1 of -2.39 min and -€5.37/operation, respectively. CONCLUSION: This is the first study in the literature that compares 6-0 Prolene versus Dermabond ® . The latter one presents advantages compared to Prolene, given that it reduces the length of surgery, reduces costs, and allows for greater flexibility in postoperative follow-up visits.

Subfoveal and Parafoveal Choroidal Thickening in Patients with Keratoconus Using the ETDRS Grid on Swept-Source OCT.

INTRODUCTION: There is growing evidence that confirms morphological changes in the posterior structures in patients with keratoconus (KC); however, isolated alterations could have been missed. This study assesses choroidal thickness (CT) in the fovea and beyond in KC eyes. METHODS: This prospective case-control and non-randomized study enrolled 107 eyes, 62 eyes of 62 patients with KC, and 45 age-matched eyes of 45 control subjects with axial length in the range of 22-26 mm. Swept-source optical coherence tomography (SS-OCT) was performed to manually measure the subfoveal choroidal thickness (SCT) using a single-line scan. CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid using the 12-lines radial scan pattern. A two-way repeated-measures analysis of variance (ANOVA) was conducted to evaluate CT variations among macular eccentricity, parafoveal area, and the interaction between both factors. CT was compared in all parafoveal areas between groups and subgroups of KC. RESULTS: SCT was significantly thicker in KC eyes (357 ± 57 µm) than in healthy eyes (325 ± 63 µm) (p < 0.001). Significant choroidal thickening was observed in the central ring and outer and inner rings of the temporal, superior, and inferior parafoveal macular areas (p < 0.001), except in the outer ring of the nasal macular zone (p > 0.05) of KC compared to healthy eyes. The CT significantly decreased from the center to the outer ring regardless of the presence of KC (p < 0.001). The choroid in the nasal macular zone was significantly thinner than that in the temporal, superior, and inferior parafoveal areas (p < 0.001). CONCLUSIONS: The choroidal structure increased its thickness not only in the subfoveal area, but also in eight parafoveal areas of the ETDRS grid encompassing a wider area of macular examination. These findings demonstrate and corroborate that keratoconus is not a purely corneal disease. Furthermore, it confirms the role that the choroidal structure has in the pathophysiology of keratoconus.

Prospective Study: Utility of Anterior Segment Optical Coherence Tomography to Identify Predictive Factors of Recurrence in Pterygium Surgery.

Background/Objectives: The main purpose of this study is to determine, by anterior segment optical coherence tomography (AS-OCT), the anatomical characteristics, both preoperatively and postoperatively, that correlate with a higher rate of pterygium recurrence after surgery with exeresis and conjunctival autograft with biological glue. Methods: A total of 50 eyes which were listed for primary pterygium surgery at an ophthalmology tertiary centre were treated with standard pterygium excision and a conjunctival autograft with tissue glue. Ten variables were measured with AS-OCT (Casia 2; Tomey Corp., Nagoya, Japan) during six control visits with all patients. Finally, statistical analysis was performed using SPSS (SPSS stadistics®, IBM®, version 21.0.0.0) for descriptive variables and R-project (The R foundation©, version 3.0.2) for the rest of the analyses, including a descriptive analysis and an inferential analysis studying prognostic factors of recurrence and their predictive capacity. Results: Among the 50 patients who underwent surgery, recurrence was detected in 8 cases (rate 16%; 95% CI: 5.8-26.2%). Most cases (n = 6) were detected 3 months after surgery. The pattern of recurrences was atrophic in two thirds of the cases; none required reintervention. Preoperative total conjunctival thickness at 3 mm was significantly increased in patients who developed recurrence. One week after surgery, epithelial and stromal thickness at 1 mm and total thickness at 3 mm proved to be useful for predicting recurrence. Both models have significant discriminant capacity. Conclusions: By imaging the graft with AS-OCT preoperatively and 7 days after surgery, the risk of future recurrence can be predicted.

Association between Tomographic Characteristics of Pterygium and Preoperative Anterior and Posterior Topography Measured by Anterior Segment Optical Coherence Tomography.

Background: The utilities of anterior segment optical coherence tomography (AS-OCT) for characterization, differential diagnosis, postoperative monitoring, and evaluation/comparison of surgical techniques in pterygium are described. Through AS-OCT, it is also possible to study the corneal astigmatic effect of pterygium. Our purpose is to study the associations between the anatomical characteristics of pterygium and the corneal topography through AS-OCT. Methods: Fifty eyes with primary pterygium in a tertiary hospital were evaluated before surgery by measuring 10 anatomical variables of pterygium and 13 topographic variables using AS-OCT (Casia 2; Tomey Corp., Nagoya, Japan). Statistical analysis was used to study the association between them. Results: Pterygium classified as flat pattern exhibited lower preoperative values of flat keratometry (K1), real flat keratometry (K1r), average keratometry (AvgK), and real average keratometry (AvgKr) compared to nodular ones. The flat pattern showed greater cylinder (CYL) and real cylinder (CLYr) values. The horizontal corneal invasion proportionally increased CYL and CYLr. Overall, larger anatomical pterygium measurements (limbus thickness (LimbusT), central pterygium thickness (CentreT), head pterygium thickness (HeadT), epithelial thickness at 1 mm (EpitT1mm), stromal thickness at 1 mm (stromT1mm), total thickness at 1 mm (TotalT1mm), total thickness at 2 mm (TotalT2mm), and total thickness at 3 mm (TotalT3mm)) resulted in lower anterior K1, K1r, AvgK, and AvgKr, and posterior K1 and AvgK values. CentreT was greater in astigmatisms against the rule than in oblique ones. Conclusions: This study demonstrates associations between preoperative topography and the NF (nodular or flat) classification of pterygium and its anatomical measurements assessed by AS-OCT.

The Role of OCT in Follow-Up of Fungal Keratitis Caused by Beauveria bassiana in Contact Lens Wearer.

A 25-year-old Caucasic female was referred to our clinic after suffering from infectious keratitis in the right eye for a month. The patient was a contact lens user and had no history of ocular trauma. Furthermore, the patient did not report any relevant antecedent. The main complaint was intense photophobia and pain. Infectious keratitis remains one of the main complications of contact lens wear and can become a therapeutic challenge in some patients. Although the most frequent causal agent is bacterial, other causes such as herpes virus, Acanthamoeba or fungi should be considered when antimicrobial therapy does not work as expected clinically. Fungal keratitis normally appears on previously damaged corneas, but it can also develop in contact lens wearers. Beauveria bassiana is an unusual pathogen which has been diagnosed more frequently lately per the clinical reports in the last 30 years, so it can be included in the diagnostic scheme when a fungal keratitis is suspected. In clinical management, AS-OCT may be a functional tool to assess the evolution and monitor the response to microbial agents and surgery. Although more studies are needed, some characteristic features have been described and can help to diagnose a fungal keratitis against other infections. AS-OCT can also play an important role in monitoring the corneal scarring after the keratitis episode, and it may be useful to plan post-infection therapy for visual rehabilitation.

Relationship between Choroidal Thickness and Anterior Scleral Thickness in Patients with Keratoconus.

PURPOSE: To evaluate the relationship between choroidal thickness (CT) and anterior scleral thickness (AST) in patients with subclinical keratoconus (SKC) and established keratoconus (KC). METHODS: This single-center prospective case-control study included 97 eyes of 97 patients: 44 KC eyes, 14 SKC eyes, and 39 age- and axial length (AL)-matched healthy eyes. Using swept-source optical coherence tomography, the AST was manually measured in four directions and the CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Principal component analysis (PCA) was used to linearly reduce the dimensionality of nine CT inputs to one significant component, CT1. A multivariate model was created to evaluate the association between CT1, AST, and several ocular parameters in SKC and KC patients. Partial correlation was then performed to adjust the confounding factors and to examine the effect of AST on CT1. RESULTS: The PCA showed that CT1 accounts for 86.54% of the total variance in the nine original CTs of the ETDRS grid. The CT1 model was associated with age, AL, and AST in the superior meridian in SKC eyes, whereas in KC eyes, it was correlated with gender, age, AL, and AST in the inferior meridian (p < 0.001). The partial correlation between CT1 and AST in the superior zone was found to be significant, positive, and strong in SKC eyes (r = 0.79, p = 0.019), whereas a significant, positive, and moderate correlation between CT1 and AST at the inferior zone (r = 0.41, p = 0.017) was observed in KC eyes. CONCLUSIONS: Choroidal tissue was significantly correlated with the anterior sclera across the vertical meridian. This relationship was observed over the superior sclera in SKC eyes, whereas in established KC, it was over the inferior sclera. These results reveal new insights regarding the interactions between the anterior and posterior structures of the KC eyes and confirm the enigma of the pathophysiology of KC.