Anterior Segment Ocular Coherence Tomography Research Articles

Value of Anterior Segment Ocular Coherence Tomography (AS-OCT) in Dryness Evaluation in Vitiligo

Abstract Background Vitiligo is an acquired depigmentation disorder of the skin and mucous membranes with an autoimmune proposed pathogenesis. The concurrence of vitiligo and ocular abnormalities has been investigated in different studies, some of which have focused on ocular surface and dry eye evaluation in vitiligo. Aim of the Work Our study aimed at evaluating the tear film changes in patients with vitiligo using clinical assessment, severity indices and AS-OCT, and comparing these findings with healthy matching controls. Patients and Methods A case control observational study that included 60 eyes (the right eye of 30 patients with vitiligo and the right eye of 30 healthy age and sex matched controls). For every patient full dermatological assessment was done and drug history taken. Every study subject was evaluated regarding their dry eye symptomatology using the (OSDI) score questionnaire, clinical effect of dry eye in various tests (Schirmer’s test, TBUT, CFS using Oxford scheme), and using the AS OCT in measuring tear film height. Results We found that vitiligo patients had a lower tear film height when compared with controls (but statistically insignificant). Patients with vitiligo were more symptomatic regarding their dry eye symptoms assessed by OSDI score, they had a shorter tear breakup time than the control group, and a higher CFS grade using Oxford scheme indicating tear film instability. Conclusion Our study revealed lower, but statistically insignificant TFH as compared to the control group. TBUT was shorter, CFS was more evident and Schirmer’s test (although did not reach statistical significance) was shorter in vitiligo patients which revealed a tendency for dry eye syndrome. Supporting these findings, the OSDI score was higher in vitiligo patients. These results indicated worse symptomatology of dry eye in vitiligo patients and lack of stability of their tear film. The findings were supported by multiple previous studies mentioned earlier.

Development and characterization of a chronic high intraocular pressure model in New Zealand white rabbits for glaucoma research

Glaucoma is a neurodegenerative disease characterized by visual field loss associated with optic nerve damage and ocular hypertension. The biological basis for the elevated intraocular pressure (IOP) is largely unknown, such that lowering the IOP is currently the only established treatment. Several animal models have been developed to elucidate the mechanism underlying the increased IOP and for use in drug discovery research, but their utility is often limited by the occurrence of severe intraocular inflammation and by technical challenges. In this study, we developed a rabbit glaucoma model that does not require experimental disease induction. Rabbits were chosen as the model because their eyeballs are similar in size to those of humans, and they are easy to breed.By crossing rabbit strains with inherited glaucoma, as indicated by obvious buphthalmos, we produced a strain that exhibits ocular hypertension. The IOP of the Ocular Hypertension (OH) rabbits was significantly higher than that of the wild type (WT; normal New Zealand white rabbits) from the age of 3 weeks to at least 22 weeks. The significantly larger corneal diameter of the OH rabbits indicated ocular enlargement, whereas there was no significant difference in corneal thickness compared with WT rabbits. Anterior segment ocular coherence tomography and gonioscopic observations revealed an open angle in the OH rabbits. Hematoxylin and eosin (HE) staining together with Masson's trichrome staining showed abnormal collagen accumulation in the angle of the OH rabbit's eyes. Furthermore, aqueous humor (AH) outflow imaging following an intravitreal injection of a fluorescent probe into the anterior chamber for tissue-section analysis revealed retention of the probe in the area of collagen deposition in the OH eyes. The OH rabbits also had a time-dependent increase in the cup/disc ratio.In conclusion, investigations using our newly developed rabbit model of open-angle ocular hypertension showed that abnormal accumulation of extracellular matrix at the angle increased AH outflow resistance in the conventional outflow pathway, leading to a high IOP. Furthermore, the OH rabbits exhibited glaucomatous optic disc cupping over time. These findings suggest the utility of the OH rabbits as a model for open-angle glaucoma (OAG).

Central corneal distortion after small-incision lenticule extraction.

A 33-year-old woman with a prior history of small-incision lenticule extraction (SMILE) presented with gradual deterioration of vision in her right eye since the surgery. She had undergone bilateral SMILE for myopic correction (-7.00 diopters [D] in the right eye and -6.00 D in the left eye) 3 weeks prior. SMILE was performed with a Zeiss VisuMax femtosecond laser system, with a cap thickness of 120 µm, a cap diameter of 7.50 mm, and a lenticule diameter of 6.50 mm. At the completion of the surgery, loose epithelium was noted at the SMILE incision bilaterally, and bandage contact lenses were placed in both eyes. On the first postoperative day, the patient's uncorrected distance visual acuity (UDVA) was 20/40 in both eyes. The bandage lenses were removed from both eyes, with the epithelium intact. At the first-week postoperative visit, her visual acuity was recorded as 20/30 in the right eye and 20/20 in the left eye. She noticed her vision in the right eye was not as sharp as that in her left eye. She denied experiencing any pain, redness, or ocular surface irritations. She was advised to return to the clinic for a 1-month postoperative visit and continue with aggressive lubrication in both eyes. However, a week later, the patient returned for an emergency visit, citing significant central visual distortion in the right eye and difficulty working on the computer. At this visit, her UDVA and corrected distance visual acuity (CDVA) was 20/50 in the right eye and 20/15 in the left eye at both near and far distances. A slitlamp examination revealed mild central changes in the right eye. She once again denied any pain, redness, or irritation. She was advised to continue with artificial tears and return to the office in 1 week for further observation of the central distortion in her right eye. Upon returning to the clinic at the third postoperative week, the patient still complained of central visual changes in the right eye, with a visual acuity of 20/70. Further slitlamp examination revealed a nonspecific central haze in the same eye, but there was no corneal staining or signs of epithelial defects. Anterior segment ocular coherence tomography (AS-OCT) and NIDEK topography were performed, showing the same central distortion in the right eye (Figures 1 and 2JOURNAL/jcrs/04.03/02158034-202311000-00016/figure1/v/2023-10-18T004638Z/r/image-tiffJOURNAL/jcrs/04.03/02158034-202311000-00016/figure2/v/2023-10-18T004638Z/r/image-tiff). Based on the examination and images provided, what is your working medical diagnosis? What other medical conditions are in your differential diagnosis? What medical and/or surgical interventions would you recommend, if any?

Comparative study of the effects of laser peripheral iridotomy and cataract surgery on anterior chamber angle parameters in primary angle closure suspect patients

IntroductionProphylactic laser peripheral iridotomy (LPI) and cataract surgery are considered the primary treatments for primary angle closure suspect (PACS) as they have proven effectiveness in widening the iridocorneal angle and...

Refractive Error and Anterior Chamber Depth as Risk Factors in Primary Angle Closure Disease: The Chinese American Eye Study.

The risk of primary angle closure disease (PACD) rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Refractive error (RE) is useful for angle closure risk stratification in the absence of biometric data. To assess the role of RE and anterior chamber depth (ACD) as risk factors in PACD. Chinese American Eye Study participants received complete eye examinations including refraction, gonioscopy, amplitude-scan biometry, and anterior segment ocular coherence tomography imaging. PACD included primary angle closure suspect (≥3 quadrants of angle closure on gonioscopy) and primary angle closure/primary angle closure glaucoma (peripheral anterior synechiae or intraocular pressure >21 mm Hg). Logistic regression models were developed to assess associations between PACD and RE and/or ACD adjusted for sex and age. Locally weighted scatterplot smoothing curves were plotted to assess continuous relationships between variables. Three thousand nine hundred seventy eyes (3403 open angle and 567 PACD) were included. The risk of PACD increased with greater hyperopia [odds ratio (OR) = 1.41 per diopter (D); P < 0.001] and shallower ACD (OR = 1.75 per 0.1 mm; P < 0.001). Hyperopia (≥ + 0.5 D; OR = 5.03) and emmetropia (-0.5 D to +0.5 D; OR = 2.78) conferred a significantly higher risk of PACD compared with myopia (≤0.5 D). ACD (standardized regression coefficient = -0.54) was a 2.5-fold stronger predictor of PACD risk compared with RE (standardized regression coefficient = 0.22) when both variables were included in one multivariable model. The sensitivity and specificity of a 2.6 mm ACD cutoff for PACD were 77.5% and 83.2% and of a +2.0 D RE cutoff were 22.3% and 89.1%. The risk of PACD rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Although RE is a weaker predictor of PACD than ACD, it remains a useful metric to identify patients who would benefit from gonioscopy in the absence of biometric data.

Inadvertent filtering bleb due to extracapsular cataract extraction wound reopening after mitomycin C use: a case report

Background Mitomycin C has been used adjunctively in various procedures, including pterygium excision. Delayed wound healing, the long-term complication of mitomycin C, can occur several years later and may rarely cause a subsequent inadvertent filtering bleb. However, conjunctival bleb formation from the reopening of an adjacent surgical wound after mitomycin C use has not been reported.Case presentationA 91-year-old Thai woman had undergone pterygium excision 26 years ago, with adjunctive mitomycin C, as well as an uneventful extracapsular cataract extraction in the same year. The patient developed a filtering bleb without glaucoma surgery or trauma approximately 25 years later. Anterior segment ocular coherence tomography illustrated a fistula connected between the bleb and anterior chamber at the scleral spur. The bleb was observed without further management, as no hypotony or bleb-related complications occurred. The symptoms/signs of bleb-related infection were advised.Conclusions This is a case report of a rare novel complication of mitomycin C application. Conjunctival bleb formation from the reopening of surgical wound, which was related to the previous mitomycin C use, could occur after a few decades.

Full-Thickness Compressive Corneal Sutures with Removal of Anterior Chamber Air Bubble in the Management of Acute Corneal Hydrops

Acute hydrops is a rare complication of corneal ectatic disease, which occurs secondary to Descemet membrane break. Spontaneous resolution of this condition is associated with longstanding ocular discomfort and corneal scar. Intracameral gas/air injection with or without corneal suturing, anterior segment ocular coherence tomography (ASOCT)-guided drainage of intrastromal fluid, and penetrating keratoplasty are some of the described surgical interventions to manage this condition. The purpose of our study was to assess the effect of full-thickness corneal suturing as a solo treatment in the management of acute hydrops. A total of five patients with acute hydrops received full-thickness corneal sutures perpendicular to their Descemet break. A complete resolution of symptoms and corneal oedema was observed between 8 to 14 days post-operation with no complications. This technique is simple, safe, and effective in the management of acute hydrops and saves patients from a corneal transplant in an inflamed eye.

Long-term Safety and Efficacy of Corneal Collagen Crosslinking in a Pediatric Group With Progressive Keratoconus: A 7-year Follow-up

To assess effectiveness and safety of corneal crosslinking (CXL) to reduce keratoconus (KC) progression and improve visual acuity among children with progressive KC and to analyze the use of 20% dextran-based (Dextran) and 1% hydroxypropyl methylcellulose-based (HPMC) riboflavin. Prospective, clinical cohort study METHODS: Standard CXL (SCXL) was performed in 74 eyes (58 patients, 45 males, mean age 13.0 ± 2.1 years): 53 eyes with HPMC and 21 with Dextran. Examinations were performed at baseline, 3 and 6 months, and 1, 2, 3, 4, 5, and 7 years of follow-up, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), a complete ophthalmologic examination, anterior segment ocular coherence tomography, Scheimpflug corneal tomography, and specular microscopy. UDVA and CDVA improved at all periods with statistically significant differences in CDVA at 1, 2, and 3 years. Compared with baseline, maximum K (Max K) reduced throughout the 7-year follow-up. Mean thinnest pachymetry (Th Pachy) decreased significantly at 3 months and remained low; in the Dextran group, the Th Pachy mean value returned to baseline 6 months postoperatively. After CXL, 1.5 diopter progression in max K was 1.4% to 14.6% of eyes; worsening was found at 4 to 7 years postoperatively. SCXL reduced KC progression in children up to 7 years of follow-up and revealed improvement and stability of UDVA and CDVA in 82% of eyes. For visual acuity and KC stability, no statistically significant difference was observed between Dextran-HPMC. The HPMC group showed persistent cornea thinning, raising concerns about its use in SCXL.

Dry eye disease and tear film assessment through a novel non-invasive ocular surface analyzer: The OSA protocol.

We describe the role of OSA as a new instrument in the study of dry eye, and we recommend a protocol for conducting the tests as well as describe the advantages and disadvantages compared with other instruments. A comparison with other ocular surface devices (Tearscope Plus, Keratograph 5M, anterior-segment ocular coherence tomography, Easy Tear View-Plus, LipiView, IDRA, and LacryDiag) were presented due to manual or automatic procedure and objective or subjective measurements. The purpose of this study was to describe the OSA as new non-invasive dry eye disease diagnostic device. The OSA is a device that can provide accurate, non-invasive and easy-to-use parameters to specifically interpret distinct functions of the tear film. This OSA protocol proposed a lesser to higher non-invasive ocular surface dry eye disease tear film diagnostic methodology. A complete and exhaustive OSA and OSA Plus examination protocol was presented within the subjective questionnaire (Dry Eye Questionnaire 5, DEQ5), limbal and bulbar redness classification (within the Efron grade Scale, interferometry lipid layer thickness (LLT) (according to Guillon pattern), tear meniscus height (manually or automatic), first and mean non-invasive break up time (objective and automatic) and meibomian gland (MG) dysfunction grade and percentage (objective and automatic). The OSA and OSA Plus devices are novel and relevant dry eye disease diagnostic tools; however, the automatization and objectivity of the measurements can be increased in future software or device updates. The new non-invasive devices supposed represent a renewal in the dry eye disease diagnosis and introduce a tendency to replace the classic invasive techniques that supposed less reliability and reproducibility.

Uveal Melanoma

Uveal melanoma, a malignant proliferation of melanocytes in the uvea, is the most common primary tumor of the eye in adults. The purpose of this review is to discuss the risk factors, clinical presentation, diagnosis, prognosis, and management, while providing information about novel viewpoints and tools for diagnosis and treatment of uveal melanoma. Blue-light exposure, BAP1 polymorphisms, complete monosomy 3, and history of ocular melanocytosis are the greatest risk factors for the development of uveal melanoma. Uveal melanoma can first present either on routine eye exam or upon presentation with flashes, floaters, and visual field defects. Diagnosis of uveal melanoma is made with anterior segment ocular coherence tomography or ultrasound biomicroscopy. Fine-needle biopsy of the lesion often follows diagnosis, with gene expression profiling being the best prognostic indicator for uveal melanoma. The gold standard for treatment of uveal melanoma is plaque brachytherapy. Other treatment possibilities for uveal melanoma include enucleation, charged-particle radiation therapy, transpupillary thermotherapy and photodynamic thermotherapy. Uveal melanoma may be fatal if untreated and subsequently metastasizes. Hopefully, earlier detection methods including the use of circulating tumor cells, circulating tumor DNA, and circulating MicroRNA and subsequent treatment using novel targeted therapies like high-intensity focused ultrasound, iontophoresis and electrochemotherapy would be crucial to improving prognosis in the future.

The detection of keratoconus using novel metrics derived by anterior segment optical coherence tomography.

To determine through a feasibility study whether anterior and posterior corneal arc length and cross-sectional area measured using anterior segment ocular coherence tomography (AS-OCT) can distinguish between healthy and keratoconic corneas. Patients diagnosed with keratoconus along with healthy controls underwent AS-OCT. ImageJ was used to determine the central 6mm anterior and posterior corneal arc lengths and cross-sectional areas. Each length and area was then divided into 1-mm segment and relative differences compared. Twenty-five eyes from 15 patients with keratoconus, along with 25 eyes from 14 healthy controls were enrolled. There was a statistically significant difference in anterior and posterior corneal arc lengths as well as corneal cross-sectional area (p = 0.006, p = 0.005, p = 0.01, respectively). When selecting for the less advanced keratoconus eye, it was noted that posterior corneal arc length was longer in the paracentral temporal segment (1003 vs. 1010µm, p = 0.04) and that greater change in corneal cross-sectional areas occurred between adjacent segments in less advanced keratoconus eyes. AS-OCT is capable of reliably measuring corneal arc lengths in patients with keratoconus and healthy patients. Both anterior and posterior corneal arc lengths along with central cross-sectional areas are statistically different between healthy and keratoconus eyes.

"Intraoperative Anterior Segment Ocular Coherence Tomography in Ophthalmic Surgery"

Ayala Katzir* and Itay Lavy Author Affiliations Department of Ophthalmology, Hadassah-Hebrew University Teaching Hospital, Jerusalem, Israel Received: October 18, 2021 | Published: October 26, 2021 Corresponding author: Ayala Katzir, Department of Ophthalmology, Hadassah-Hebrew University Teaching Hospital, Jerusalem, Israel DOI: 10.26717/BJSTR.2021.39.006328

New algorithm for corneal densitometry assessment based on anterior segment optical coherence tomography.

To describe a new algorithm to measure corneal densitometry based on images obtained by swept source anterior segment ocular coherence tomography (SS-AS-OCT) and establish standard densitometry values in a group of normal eyes. A total of 111 healthy participants (195 eyes) were enrolled in this study. Using a MATLAB designed algorithm, the cornea was segmented into three layers: anterior, posterior and mid-stroma, and it was divided into two concentric areas, 0-2 and 2-4 mm, resulting in nine areas for the analysis. The mean corneal densitometry values were calculated and expressed as grayscale units (GSU). The mean age was 57 years (range 22-87), with 100 (51.3%) right eyes and 95 (48.7%) left eyes. The total corneal densitometry was 86.9 ± 12.1 GSU. The mid-stroma layer had the highest densitometry values, 87.4 ± 12.1 GSU, and the anterior layer had the lowest values, 81.9 ± 14.2 GSU. Densitometry differences between the anterior layer and the mid-stroma layer (P < 0.001), as well as the anterior layer and the posterior layer (P < 0.05) were statistically significant. The 0-2 mm concentric area had higher mean densitometry values, 97.8 ± 12.7 GSU, and the differences were significant compared to the 2-4 mm concentric area (P < 0.001). No correlation was found between the corneal densitometry values and gender or age. The new MATLAB segmentation algorithm for the analysis of corneal SS-AS-OCT images is capable to objectively assess corneal densitometry. We provide standard and normal data for better clinical and research approach.

Non-malignant conjunctival epithelial masses with ocular surface squamous neoplasia-like optical coherence tomography features

PurposeTo observe and describe the anterior segment optical coherence tomography features of limbally localised non-malignant epithelial mass lesionsMethodsThirteen patients (age: 66.9 ± 16.3 years) with conjunctival mass suggesting ocular surface squamous neoplasia with biomicroscopic examination were imaged using anterior segment ocular coherence tomography (anterior segment optical coherence tomography)/Cirrus HD-OCT, Model 4000, Carl Zeiss Meditec, Inc., Dublin, CA, and Spectralis HRA + OCT system, Heidelberg Engineering, Vista, CA/. Cases with ocular surface squamous neoplasia-like anterior segment optical coherence tomography (hyperreflective, thickened epithelium and an abrupt transition from normal to abnormal) were included in the study. Maximal thickness of the epithelium was measured. Histological diagnosis was gained from an excisional or incisional biopsy or impression cytology specimens.ResultsIn six patients (age: 68.5 ± 15.4 years) with ocular surface squamous neoplasia-like anterior segment optical coherence tomography features, the histological diagnosis was other than ocular surface squamous neoplasia (papilloma, parakeratosis and a keratotic plaque with mild dysplasia), and ocular surface squamous neoplasia in seven cases (age: 65.6 ± 18.0 years). The maximal epithelial thickness was between 250 and 859 µm in non-ocular surface squamous neoplasia cases and between 252 and 596 µm in ocular surface squamous neoplasia cases.ConclusionNon-malignant epithelial lesions can mimic ocular surface squamous neoplasia on anterior segment optical coherence tomography.

Evaluating the safety and efficacy of compression sutures with intracameral perfluoropropane (C3F8) in the management of acute corneal hydrops.

To evaluate the safety and efficacy of using corneal compression sutures with intracameral perfluoropropane (C3F8) in patients presenting with acute corneal hydrops in ectatic disorders. A retrospective analysis was done for 43 eyes of patients of acute corneal hydrops, managed using a combination of intracameral 14% C3F8 and full-thickness compression sutures. Time for resolution of edema, corneal thickness (CT) change on anterior segment ocular coherence tomography (ASOCT), and visual outcomes were assessed. Corneal edema resolved with a mean duration of 14.8 ± 3.5days (range 10-21). The mean CT on ASOCT decreased from a mean of 1437µm (689-2770µm) preoperatively to 543µm (434 -66µm) on the complete resolution of corneal edema. Our results suggest that full-thickness compression sutures and intracameral C3F8 injection can restore the imperviousness of posterior stroma. This technique appears to be a safe and effective technique for faster resolution of corneal edema post hydrops.

Comparative Results of “Epi-Off” Conventional versus “Epi-Off” Accelerated Cross-Linking Procedure at 5-year Follow-Up

Purpose The aim of our study was to compare the long-term efficacy and safety of “epi-off” conventional and “epi-off” accelerated corneal cross-linking (CXL) in patients with progressive keratoconus. Methods “Epithelial-off” (“Epi-off”) CXL using the conventional technique (3 mW/cm2, 30 minutes) was performed in 93 eyes of 93 patients (S-CXL group) and “epi-off” accelerated method (9 mW/cm2, 10 minutes) in 76 eyes of 76 patients with progressive KCN (A-CXL group). Cases with different stages of keratoconus and topographic evidence of progression were included. Main outcomes comprised refraction, keratometry measurements, uncorrected (UCVA) and best-corrected visual acuity (BCVA), and topographical indices. Micromorphological analysis was assessed by anterior segment ocular coherence tomography (AS-OCT). The follow-up period was 5 years. Results In both groups, Kflat presented similar results: decrease at 1 year (p=0.465), at 2 years (p=0.672), at 3 years (p=0.198), at 4 years (p=0.32), and at 5 years (p=0.864). In both groups, Ksteep presented a similar decrease at 1 year (p=0.709), at 2 years (p=0.455), at 3 years (p=0.43), at 4 years (p=0.57), and at 5 years (p=0.494), with no statistically significant difference. Decrease in Kavg was similar in both groups at all analyzed time points (p=0.18 at 1 year, p=0.093 at 2 years, p=0.57 at 3 years, p=0.154 at 4 years, and p=0.247 at 5 years). Kmax had a similar decrease in both groups at 1 year (p=0.06), at 2 years (p=0.09), at 3 years (p=0.126), at 4 years (p=0.113), and at 5 years (p=0.114). There was no statistically significant difference between the cylinder decrease in both groups (p=0.349 at 1 year, p=0.6782 at 2 years, p=0.299 at 3 years, p=0.0943 at 4 years, and p=0.144 at 5 years). The BCVA values were statistically significantly higher than the preoperative values in both groups at all time points (p < 0.05). Topographical indices such as thinnest corneal point (TP), corneal volume (CV), index vertical asymmetry (IVA), index of vertical asymmetry (ISV), index of height asymmetry (IHA), index of height decentration (IHD), Belin/Ambrosio Enhanced Ectasia Display (BAD_D), and Ambrosio retinal thickness (ART Max) were significantly statistically decreased compared with baseline at all time points, in both groups. Conclusion “Epi-off” accelerated and conventional CXL have the same efficacy in terms of improvement in visual and topographic outcomes.

Descemet’s Membrane Injury Post YAG Peripheral Iridotomy

Neodymium: Yittrium - Aluminium-Garnet (Nd YAG) laser iridotomy is one of the most common laser procedures performed in the Asian continent as the proportion of Angle closure glaucoma cases is significant. The Nd YAG iridotomy appears to be a simple outpatient procedure but can result in a number of complications including haemorrhage, cataract formation, dysphotopsia, intraocular pressure elevation and corneal endothelial damage resulting in corneal decompensation at a later date. A forty one year old female patient, a case of Primary Angle Closure Suspect (PACS), who had undergone a Nd YAG laser iridotomy of both the eyes elsewhere presented to us for a second opinion. The anterior segment examination was unremarkable except for the bilateral peripheral Iridotomies. The slit lamp examination revealed three small defects in the temporal cornea at the level of the Descemet’s membrane and posterior stroma overlying the iridotomy in the right eye. A specular microscopy did not reveal any endothelial damage or change in the cell morphology overlying the iridotomy or in other areas. Anterior segment Ocular Coherence Tomography (OCT) demonstrated the exact nature of the injury to the Decemets membrane. To the best of our knowledge, its the first case report in the literature of a Descmet’s membrane injury following a ND-YAG laser iridotomy. It emphasizes the importance of accurate focus on the iris and choosing a quadrant with adequate distance between the iris and the cornea to avoid injury to surrounding structures.

Comparative Results Between "Epi-Off" Conventional and Accelerated Corneal Collagen Crosslinking for Progressive Keratoconus in Pediatric Patients.

PurposeThe aim of our study was to evaluate the efficacy and safety of epi-off conventional and accelerated corneal collagen cross-linking in the treatment of progressive keratoconus in pediatric patients up to 4 years after treatment.Patients and methodsConventional (standard) CXL epi-off technique was performed in 37 eyes (S-CXL group) and accelerated CXL in 27 eyes (A-CXL group). Refraction, keratometry, cylindrical equivalent, spherical equivalent, slit lamp examination, pachymetry, corneal tomography, anterior segment ocular coherence tomography and visual acuity were performed up to 4 years.ResultsIn the S-CXL group: the flat K values decreased from 47.41±3.39 D to 45.36±3.62 D at 4 years (p=0.004); steep K decreased from 51.98±4.11 to 50.21±4.81 D at 4 years (p=0.0078); mean K decreased with 1.99 D at 4 years (p=0.009). In the A-CXL group: the flat K values decreased from 46.97±4.17 D to 44.97±4.24 D at 4 years (p=0.048); steep K decreased from 50.55±4.10 D to 48.75±4.17 D at 4 years (p=0.0287); mean K decreased from 48.79±3.86 D to 46.86±4.11 D at 4 years (p=0.0356). The preoperative mean UCVA in the S-CXL group was 0.8 ±0.23 logMar and improved during the follow-up reaching 0.65 ±0.24 logMar at 4 years (p=0.072). The baseline mean UCVA in A-CXL group was 0.77±0.25 logMar and increased during the follow-up to 0.63 ±0.25 logMar at 4 years (p=0.0039). A similar improvement of BCVA was observed during the follow-up.ConclusionEpi-off conventional and accelerated CXL are efficient procedures for progressive keratoconus in pediatric patients. Accelerated and conventional CXL were comparable at all time points and both represent viable options for the therapy of KC in these patients.

Delayed onset of pressure-induced interlamellar stromal keratitis in a patient with recurrent uveitis

Introduction:Corticosteroid treatment for uveitis can lead to delayed-onset pressure-induced interlamellar stromal keratitis (PISK), even years after laser in situ keratomileusis (LASIK).A 35-year-old man presented to our clinic after experiencing blurred vision in his left eye for 1 month. For the past month, he had been prescribed topical steroid and anti-glaucomatous medication. He had undergone LASIK for both eyes 5 years earlier, and had suffered uveitis attacks in his left eye over the last 2 years.Slit-lamp examination revealed stromal haziness with interface fluid accumulation in the left eye. The left eye showed an intraocular pressure (IOP) of 35 mm Hg and visual acuity of 6/20. Anterior segment ocular coherence tomography (OCT) confirmed the diagnosis of PISK. Steroid treatment was tapered, and latanoprost treatment was started. One month later, the patient's symptoms resolved, with IOP reduced to 10 mm Hg and visual acuity increased to 6/6 in the left eye. Latanoprost treatment was discontinued to avoid potential uveitis reactivation, and the patient's visual field defect progressed and IOP rebounded. Due to evident glaucomatous damage, trabeculectomy was suggested but was refused.Conclusion:Patients with PISK plus uveitis should be treated with a tailored regimen involving corticosteroid and antiglaucomatous medication or surgical intervention based on the individual condition. Early recognition and appropriate treatment may aid in preventing severe visual sequela in such patients.

Assessment of tilt and decentration of crystalline lens and intraocular lens relative to the corneal topographic axis using anterior segment optical coherence tomography

PurposeTo investigate the tilt and decentration of the crystalline lens and the intraocular lens (IOL) relative to the corneal topographic axis using anterior segment ocular coherence tomography (AS-OCT).MethodsA sample set of 100 eyes from 49 subjects (41 eyes with crystalline lenses and 59 eyes with IOLs) were imaged using second generation AS-OCT (CASIA2, TOMEY) in June and July 2016 at Okayama University. Both mydriatic and non-mydriatic images were obtained, and the tilt and decentration of the crystalline lens and the IOL were quantified. The effects of pupil dilation on measurements were also assessed.ResultsThe crystalline lens showed an average tilt of 5.15° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 5.25° under mydriatic conditions. Additionally, an average decentration of 0.11 mm towards the temporal direction was observed under non-mydriatic conditions and 0.08 mm under mydriatic conditions. The average tilt for the IOL was 4.31° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 4.65° in the same direction under mydriatic conditions. The average decentration was 0.05 mm towards the temporal direction under non-mydriatic conditions and 0.08 mm in the same direction under mydriatic conditions. A strong correlation was found between the average tilt and decentration values of the crystalline lens and the IOL under both non-mydriatic and mydriatic conditions (all Spearman correlation coefficients, r ≥ 0.800; all P < 0.001).ConclusionWhen measured using second generation AS-OCT, both the crystalline lens and the IOL showed an average tilt of 4–6° toward the inferotemporal direction relative to the corneal topographic axis and an average decentration of less than 0.12 mm towards the temporal direction. These results were not influenced by pupil dilation and they showed good repeatability.