Anterior Segment Optical Coherence Tomography Research Articles

Evaluation of corneal power from an AS-OCT thick lens model and ray tracing: reliability of the keratometer index

Purpose: To investigate and compare different strategies of corneal power calculations using keratometry, paraxial thick lens calculations and ray tracing. Setting: Tertiary care center. Design: Retrospective single-center consecutive case series. Methods: Using a dataset with 9780 eyes of 9780 patients from a cataractous population the corneal front (Ra/Qa) and back (Rp/Qp) surface radius/asphericity, central corneal thickness (CCT), and entrance pupil size (PUP) were recorded using the Casia 2 tomographer. Beside keratometry with the Zeiss (PKZ) and Javal (PKJ) keratometer index, a thick lens paraxial formula (PG) and ray tracing (PR) was implemented to extract corneal power for pupil sizes from 2 mm to 5 mm in steps of 1 mm and PUP. Results: With PUP PKZ/PKJ overestimates the paraxial corneal power PG in around 97%/99% of cases and PR in around 80% to 85%/99%. PR is around 1/6 or 5/6 diopters (D) lower compared with PKZ or PKJ. For a 2 mm pupil PR is around 0.20/0.91 D lower compared with PKZ/PKJ and for a 5 mm pupil PR is comparable with PKZ (around 0.03 D lower) but around 0.70 to 0.75 D lower than PKJ. Conclusions: “True” values of corneal power are mostly required in lens power calculations before cataract surgery, and overestimation of corneal power could induce trend errors in refractive outcome with axial length and lens power if compensated with the effective lens position.

Supernumerary Puncta: An Uncommon Underdiagnosed Cause of Unilateral Epiphora

Introduction The presence of multiple eyelid puncta is known as supernumerary puncta. The presence of supernumerary puncta is caused by lacrimal outflow dysgenesis and can result in unilateral epiphora. Although an infrequent diagnosis, supernumerary puncta should be considered in the differential diagnosis of unilateral epiphora to allow for the correct management of patient’s symptoms. Case Report A 74-year-old white male presented with a chief complaint of unilateral epiphora of his right eye. The presence of two puncta on the inferior lid margin of one eye was noted. Further evaluation with anterior segment optical coherence tomography (OCT) revealed that both puncta were functional. Occlusion of the accessory punctum and use of artificial tears four times a day was the treatment which led to the resolution of his symptoms. Conclusion Through a careful examination and assessment, the root cause of epiphora can be determined, and the appropriate management can be pursued. Although not exceptionally rare, supernumerary puncta may be present and cause epiphora through lacrimal outflow dysgenesis. Supernumerary puncta can be identified easily with careful slit lamp examination. Probing of the punctum and anterior segment OCT can be used to identify the accessory punctum and determine its functionality.

Evaluation of pericardium patch graft thickness in patients with Ahmed glaucoma valve implantation: an anterior segment OCT study

PurposeTo evaluate the changes in thickness of tissues, specifically the pericardium patch graft (PPG) covering the silicone tube in Ahmed Glaucoma Valve (AGV) surgery.Study designProspective observational study.MethodsThis study included cases with refractory glaucoma that underwent AGV implantation with PPG coverage. Conjunctival epithelium, stroma and PPG thickness covering the tube were measured using anterior segment optical coherence tomography (AS-OCT) at 1, 6 and 12 months. Additionally, the same measurements were taken 1500 µm away from the tube as a control for the central measurements.ResultsTwenty-seven eyes of 27 patients were evaluated in the study. Although PPG thickness decreased significantly in both regions, the amount of reduction was more pronounced centrally. Centrally, the reduction rate was 21.2% and 34.8% during the 1-6 months period and 6-12 months period, while peripherally it was 3.5% and 5.1%, respectively. No change was observed in the thickness of the epithelium during the follow-up period. There was a significant thinning of the stroma in the central and peripheral regions during the 1-6 months period (30.5% and 17%, respectively). No cases of exposure were observed during the follow-up period.ConclusionAlthough the most evident thinning of the layers covering the tube was observed in the early postoperative period, PPG showed a stable decrease even in the late period. The progressive reduction in the PPG thickness observed also in the peripheral region indicates that factors beyond mechanical forces contribute to this degenerative process. AS-OCT could be a valuable non-invasive tool in clarifying this process.

Performance of anterior segment OCT-based algorithms in the opportunistic screening for primary angle-closure disease

PurposeThis study aimed to investigate the performance of deep learning algorithms in the opportunistic screening for primary angle-closure disease (PACD) using combined anterior segment parameters. MethodsThis was an observational, cross-sectional hospital-based study. Patients with PACD and healthy controls who underwent comprehensive eye examinations, including gonioscopy and anterior segment optical coherence tomography (ASOCT) examinations under both light and dark conditions, were consecutively enrolled from the Department of Ophthalmology at the Beijing Tongren Hospital between November 2020 and June 2022. The anterior chamber, anterior chamber angle, iris, and lens parameters were assessed using ASOCT. To build the prediction models, backward logistic regression was utilized to select the variables to discriminate patients with PACD from normal participants, and the area under the receiver operating characteristic curve was used to evaluate the efficacy of the opportunistic screening. ResultsThe data from 199 patients (199 eyes) were included in the final analysis and divided into two groups: PACD (109 eyes) and controls (90 eyes). Angle opening distance at 500 μm, anterior chamber area, and iris curvature measured in the light condition were included in the final prediction models. The area under the receiver operating characteristic curve was 0.968, with a sensitivity of 91.74 % and a specificity of 91.11 %. ConclusionASOCT-based algorithms showed excellent diagnostic performance in the opportunistic screening for PACD. These results provide a promising basis for future research on the development of an angle-closure probability scoring system for PACD screening.

Surgically induced astigmatism in the scleral fixated 'Carlevale' IOL technique.

To evaluate the surgically induced astigmatism over a 6-month follow-up period in patients who underwent scleral IOL fixation using an acrylic single-piece IOL with special haptics designed for sutureless scleral fixation. We conducted a prospective longitudinal study at a single site with a single surgeon. We included patients who received transscleral IOL implantation following the Carlevale technique and were followed up post-operatively for 24 weeks. We measured the patient's refraction at baseline, week 12 and week 24 using the best corrected visual acuity at 4 m (EDTRS chart). We performed corneal tomography at every visit using an anterior segment optical coherence tomography (AS-OCT). We evaluated surgically induced astigmatism (SIA) and refraction during each follow-up visit and compared them to baseline. We then assessed changes in SIA over time. In total, 27 eyes of 27 patients consisting of 16 female and 11 male individuals were evaluated. The mean patient age was 71 ± 11.7 years, mean axial length was 24.30 ± 1.47 mm (range: 21.4-27.23) and mean white-to-white distance was 12.07 ± 0.40 mm (range: 11.4-12.7). The mean SIA decreased from 1.78 ± 0.96D at week 1 significantly to 0.80 ± 0.55D at week 12 (p < 0.001) and then stayed unchanged around 0.82 ± 0.72D at week 24 (p = 1.0). The scleral fixated Carlevale IOL and its implantation procedure were found to result in a predictable SIA of <1D after 24 weeks. However, the axis orientation of the SIA appeared to be random, making it unsuitable for implementation in toric IOL calculations.

Evaluation of scleral thickness in patients with pterygium

ObjectivesTo evaluate scleral thickness measurements of pterygium patients using anterior segment optical coherence tomography (AS-OCT) and to compare them with healthy individuals. Material and methodsScleral thickness was measured from 2, 4, 6 mm posterior to the scleral spur with AS-OCT (Swept Source OCT Triton, Topcon, Japan) in 4 quadrants (superior, inferior, nasal and temporal). ResultsEyes with pterygium were determined as Group 1, and contralateral eyes without pterygium were determined as Group 2. Healthy controls were determined as Group 3. In the measurements made from 4 mm posterior, no significant difference was found between Group 1 and Group 2 in any quadrants (p > 0.05). In all measurements made from 4 mm posterior to the scleral spur, scleral thickness was found to be significantly higher in Group 1 compared to Group 3 (p < 0.05). Measurements made from 2 mm posterior to the scleral spur in Group 1 was found to be significantly higher in the superior and temporal quadrants compared to Group 3 (p = 0.05), while no significant difference was found in the nasal and inferior quadrants (p > 0.05). When Group 2 and Group 3 were compared, scleral thickness measurements made from 4 mm posterior to the scleral spur was significantly thicker in all quadrants in Group 2 (p > 0.05). ConclusionScleral thickness was found to be higher in pterygium patients compared to healthy controls, especially when measured from 4 mm posterior to the scleral spur. It has been predicted that high scleral thickness may be associated with high fibroblast activity in subconjunctival structures, and this may predispose to pterygium.

Estimation of angle parameters by ASOCT and biometric parameters by optical biometer in eyes with occludable angles and open angles.

To compare anterior chamber angle (ACA) parameters measured by Anterior Segment Optical Coherence Tomography (ASOCT) and biometric parameters measured by Swept-Source (SS) OCT-based biometry among patients with suspected occludable angles and open angles. An analytical, cross-sectional study was performed on subjects attending our ophthalmology outpatient department with suspected occludable angles (van Herick grades 0, 1, and 2) in group 1, and with open angles (van Herick grades 3 and 4) in group 2. Each subject underwent a complete ophthalmic examination to exclude any intraocular pathology like cataract. We recruited 128 eyes of 64 subjects, 34 in group 1 and 30 in group 2. Each eye was henceforth subjected to ASOCT (Spectralis, Heidelberg Engineering, Heidelberg) and SS-OCT-based optical biometry (IOL Master 700, Carl Zeiss Meditec AG). Anatomical parameters were recorded and compared between the two groups. The main outcome measures of the study included nine ASOCT parameters (central corneal thickness [CCT], lens vault, AOD750, ACA, TISA750 [nasal and temporal], and ACW) and five optical biometric parameters (CCT, ACD, WTW, LT, and axial length). We found a significant difference (p < 0.05) among all the anatomical parameters between the two groups, except CCT which was not significantly different (p = 0.297). ASOCT and SSOCT biometry overcome the challenges of gonioscopy and allow screening for angle closure disease in otherwise normal subjects. ASOCT may serve as an alternative to gonioscopy as it clearly separates occludable angles from open angles in a non-invasive and objective manner.

Analysis of Graft Detachments and Re-Bubblings After 450 Descemet Membrane Endothelial Keratoplasty Procedures.

To objectify the indication for re-bubbling by analyzing graft detachments (GDs) after Descemet membrane endothelial keratoplasty. In this retrospective monocentric observational study, re-bubbling cases of 450 Descemet membrane endothelial keratoplasties and the percentage of the residual gas filling (RGF) in the anterior chamber on the first postoperative day were collected. The number/location/extent of GDs and the corneal thickness above GDs were analyzed using anterior segment optical coherence tomography. From a total of 450 grafts, 384 (85.3%) had at least a minimal degree GD. One hundred twenty-two of 450 grafts (27.1%) underwent at least 1 re-bubbling. The mean RGF was significantly lower in eyes with GD (67.7 ± 12.6%) than in eyes without GD (74.2 ± 11.3%). GDs occurred most frequently in the inferotemporal quadrant (46.0%). GDs were significantly more likely to require a re-bubbling when the central parts of the graft were affected (94.0% vs. 35.7%). The number of detachments per graft was directly proportional to the re-bubbling rate. The GDs which required a re-bubbling were on average 56 μm higher and 461 μm wider than the untreated ones. The cornea above the GDs that needed a re-bubbling was significantly thicker than above the untreated GDs (mean 988 ± 102 μm vs. 951 ± 99 μm). The RGF seems to be a major influencing factor for graft attachment. The most susceptible location of the GD is inferotemporal. The main factors that need to be investigated to decide if a re-bubbling is required are the number of detachments per graft, their dimensions, whether the central portions of the graft are involved, and the corneal thickness above GDs.

Effects of graft detachment on the central corneal thickness after uncomplicated Descemet membrane endothelial keratoplasty

PurposeTo determine if early central corneal thickness (CCT) and best-corrected visual acuity (BCVA) changes indicate graft detachment after uncomplicated Descemet membrane endothelial keratoplasty (DMEK).MethodsIn this analysis of our prospectively collected ADDA registry data (https://drks.de/search/de/trial/DRKS00027180), 45 pseudophakic eyes underwent DMEK surgery at the Department of Ophthalmology, RWTH Aachen University. Anterior segment optical coherence tomography (AS-OCT), the presence of stromal ripples on the posterior corneal surface, and BCVA measurements were assessed prior to, 1 day, 1 week, 1 month, and 6 months after surgery.ResultsEyes were categorized into three groups: no graft detachment (group 1) (20/45; 44.4%), < 1/3 graft detachment (group 2) (14/45; 31.1%), ≥ 1/3 graft detachment followed by rebubbling (group 3) (11/45; 24.4%). Eyes in group 3 had a greater CCT prior to (746.8 ± 95.8 µm vs. 665.0 ± 74.4 µm, P = 0.041), and 1 week (666.8 ± 119.5 µm vs. 556.5 ± 56.8 µm, P = 0.001) after DMEK compared to group 1. By 1 month, CCT in all groups aligned. Comparing prior to and 1 week after DMEK, none of the eyes in group 1 had an increase in CCT, while the CCT increased in 25.0% of eyes in group 2 and 22.2% in group 3. In group 1, 90.0% had a CCT of < 600 µm 1 week after DMEK, compared to only 50.0% in group 2 and 36.4% in group 3. In group 1, 90.0% (18/20) had an improved BCVA 1 week after DMEK, while in groups 2 and 3, 86.7% (12/14) and 18.2% (2/11) improved, respectively. One patient in group 3 showed posterior stromal ripples 1 day and 1 week after DMEK.ConclusionIf 1 week after uncomplicated DMEK CCT is < 600 µm and has decreased from before surgery, BCVA has improved, and there are no posterior stromal ripples, a graft detachment ≥ 1/3 and the need for rebubbling are very unlikely. In all other cases, meticulous slit-lamp and OCT inspection of the peripheral graft for detachments should be advised.

Comparison of focal loss volume, global loss volume, retinal nerve fiber layer thickness, and corneal epithelial thickness in eyes with glaucoma and suspicious optic discs

Abstract: PURPOSE: The purpose of this study was to study the role of the focal loss volume (FLV), global loss volume (GLV), and other spectral-domain optical coherence tomography (SD-OCT) parameters in early diagnosis of glaucomatous damage. METHODS: A retrospective study included records of 34 eyes with early glaucoma (Group A) and 17 eyes with suspicious optic discs (Group B). Retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and corneal thickness parameters were assessed by the SD OCT (RTVue SD-OCT). These included the FLV, GLV, in addition to RNFL thickness, cup/disc ratio, GCC thickness, and anterior segment OCT for assessment of central corneal thickness and central corneal epithelial thickness. Data from both groups were subjected to statistical analysis. RESULTS: The FLV and GLV had the highest areas under the receiver operating characteristic curve in Group A eyes. FLV had higher (97.2%) specificity and was the earliest parameter to be affected by glaucomatous damage, followed by GLV. Moreover, Group A eyes had significant thinning of the RNFL (91.59 μm) compared to Group B (118.18 μm), and GCC thickness was also significantly thinner in Group A (92.07 μm) than in Group B (110.54 μm). Interestingly, Group A eyes had thinner corneal epithelium (nonsignificant) than Group B. CONCLUSION: FLV and GLV were of the greatest value in the assessment of early glaucomatous GCC degeneration.

ASSESSMENT OF ANTERIOR CHAMBER ANGLE ON ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY IN PATIENTS WITH ANGLE CLOSURE GLAUCOMA AND ANGLE CLOSURE SUSPECTS

The objective of this cross-sectional study was to determine the anterior chamber angle using anterior segment optical coherence tomography (AS-OCT) in patients diagnosed with angle closure glaucoma and angle closure suspects. The research was conducted at Shaheed Mohtarma Benazir Bhutto Medical University Larkana, spanning from March 3, 2022, to June 30, 2023. Patients meeting the inclusion criteria and diagnosed with primary angle-closure glaucoma (PACG) were enrolled in the study after obtaining informed consent. The procedure, risks, and benefits of the study were explained to the patients before obtaining consent. AS-OCT was utilized to evaluate patients suspected of primary angle closure and those with confirmed primary angle closure. The results revealed a mean age of 56.21 ± 12.31 years among the study participants, with a confidence interval of 55.04 to 57.38. The mean duration of primary angle closure glaucoma was 22.52 ± 10.98 months, with a confidence interval of 21.47 to 23.57. Of the 423 patients included in the study, 219 (52%) were male, and 204 (48%) were female. Primary angle closure suspect and primary angle closure were observed in 47 (11%) and 44 (10%) patients, respectively. In conclusion, older age, higher central corneal thickness (CCT), and shorter axial length or presence of hyperopia were identified as important independent predictors of suspicion of primary angle closure and primary angle closure. These findings underscore the significance of thorough assessment and monitoring of these parameters in patients at risk of angle closure glaucoma.

Effect of digital ocular massage on intraocular pressure and Schlemm’s canal dimensions

Digital ocular massage has been reported to temporarily lower intraocular pressure (IOP). This could be related to an enhanced aqueous humor outflow; however, the mechanism is not clearly understood. Using anterior segment optical coherence tomography, the Schlemm’s canal (SC) and trabecular meshwork (TM) can be imaged and measured. Here, 66 healthy adults underwent digital ocular massage for 10 min in their right eyes. The IOP and dimensions of the SC and TM were measured before and after ocular massage. All subjects demonstrated IOP reduction from 15.7 ± 2.5 mmHg at baseline to 9.6 ± 2.2 mmHg immediately after, and median of 11.6 mmHg 5-min after ocular massage (Friedman’s test, p < 0.001). There was significant change in SC area (median 10,063.5 μm2 at baseline to median 10,151.0 μm2 after ocular massage, Wilcoxon test, p = 0.02), and TM thickness (median 149.8 μm at baseline to 144.6 ± 25.3 μm after ocular massage, Wilcoxon test, p = 0.036). One-third of the subjects demonstrated collapse of the SC area (−2 to −52%), while two-thirds showed expansion of the SC area (2 to 168%). There were no significant changes in SC diameter (270.4 ± 84.1 μm vs. 276.5 ± 68.7 μm, paired t-test, p = 0.499), and TM width (733.3 ± 110.1 μm vs. 733.5 ± 111.6 μm, paired t-test, p = 0.988). Eyes with a higher baseline IOP demonstrated a greater IOP reduction (Pearson correlation coefficient r = −0.521, p < 0.001). Eyes with smaller SC area at baseline showed greater SC area expansion (Pearson correlation coefficient = −0.389, p < 0.001). Greater IOP reduction appeared in eyes with greater SC area expansion (Pearson correlation coefficient r = −0.306, p = 0.01). Association between change in IOP and change in TM thickness was not significant (Spearman’s ρ = 0.015, p = 0.902). Simple digital ocular massage is an effective method to lower IOP values, and change in the SC area was significantly associated with IOP changes.

Ectasia Detection by Anterior Segment Optical Coherence Tomography in Scheimpflug Tomographically Normal Keratoconus Fellow Eyes.

The purpose of this study was to determine whether the Scheimpflug tomographically normal fellow eyes of keratoconus patients are also classified as normal using an ectasia screening algorithm based on anterior segment optical coherence tomography (AS-OCT). This monocentric cross-sectional study included 22 very asymmetric ectasia patients with tomographically significant keratoconus in 1 eye and normal Scheimpflug tomography in the fellow eye. Twenty-two eyes of 22 healthy subjects served as a control group. We performed corneal tomography using Pentacam AXL (Oculus, Wetzlar, Germany) and used Belin/Ambrósio Enhanced Ectasia total deviation index as well as Belin ABCD keratoconus classification to identify Scheimpflug tomographically normal eyes. We also performed AS-OCT using Anterion (Heidelberg Engineering, Heidelberg, Germany) and analyzed for the presence of ectasia using the Screening Corneal Objective Risk of Ectasia (SCORE) algorithm, with positive values indicating ectasia suspect tomography. The SCORE value was positive in 9.1% (n = 2) of the healthy eyes, in 45.5% (n = 10) of the Scheimpflug tomographically normal eyes of keratoconus patients and in all eyes (n = 22) with tomographically significant keratoconus. The Scheimpflug tomographically normal eyes of keratoconus patients had higher SCORE values compared with healthy controls ( P < 0.001). The median (interquartile range) SCORE value was -1.7 (1.3) in healthy controls, -0.5 (2.2) in Scheimpflug tomographically normal eyes of keratoconus patients, and 11.1 (11.0) in tomographically significant keratoconus eyes. The Scheimpflug tomographically normal fellow eyes of keratoconus patients had higher AS-OCT-based SCORE values than healthy controls, with positive SCORE values found in 46% of the eyes, indicating early tomographic ectatic changes.

Descemet Membrane Endothelial Keratoplasty as Treatment for Late-Onset Interface Fluid Syndrome After Laser In Situ Keratomileusis.

We herein present Descemet membrane endothelial keratoplasty (DMEK) as an effective surgical means of treatment for the management of interface fluid syndrome (IFS) in a series of cases with distant history of laser in situ keratomileusis (LASIK). Three cases from a single institution were included. All patients had documented IFS in the setting of history of LASIK. All 3 patients underwent DMEK for the treatment of IFS. Visual acuity, clinical findings, pachymetry, endothelial cell count, and anterior segment optical coherence tomography were recorded. We describe 3 cases of late-onset IFS that developed in eyes many years after LASIK (ranging from 15 to 31 years). All 3 patients had clinically significant corneal edema and evidence of poor endothelial function at the time of IFS diagnosis. DMEK was subsequently performed in each case. All 3 eyes showed resolution of corneal edema and improvement in best-corrected visual acuity after DMEK. DMEK can provide successful visual and anatomical recovery in patients who have had previous LASIK and experience late-onset IFS due to endothelial cell dysfunction.

Applications of Imaging Technologies in Fuchs Endothelial Corneal Dystrophy: A Narrative Literature Review.

Fuchs endothelial corneal dystrophy (FECD) is a complex genetic disorder characterized by the slow and progressive degeneration of corneal endothelial cells. Thus, it may result in corneal endothelial decompensation and irreversible corneal edema. Moreover, FECD is associated with alterations in all corneal layers, such as thickening of the Descemet membrane, stromal scarring, subepithelial fibrosis, and the formation of epithelial bullae. Hence, anterior segment imaging devices that enable precise measurement of functional and anatomical changes in the cornea are essential for the management of FECD. In this review, the authors will introduce studies on the application of various imaging modalities, such as anterior segment optical coherence tomography, Scheimpflug corneal tomography, specular microscopy, in vitro confocal microscopy, and retroillumination photography, in the diagnosis and monitoring of FECD and discuss the results of these studies. The application of novel technologies, including image processing technology and artificial intelligence, that are expected to further enhance the accuracy, precision, and speed of the imaging technologies will also be discussed.

Anterior Segment Optical Coherence Tomography in Uveitis-Glaucoma-Hyphema Syndrome

ABSTRACT Purpose Uveitis-Glaucoma-Hyphema (UGH) syndrome results from contact between the intraocular lens (IOL) and the iris or ciliary body, leading to uveal structure erosion and blood-aqueous barrier breakdown. Treatment involves various drugs, with IOL removal often being necessary. Diagnosis relies on clinical signs, but imaging techniques like ultrasound biomicroscopy (UBM) or anterior segment optical coherence tomography (AS-OCT) are crucial. AS-OCT accurately depicts IOL position and potential contact, emerging as a primary alternative to UBM in the diagnosis. Our study aimed to correlate AS-OCT findings with clinically detectable iris atrophy in pseudophakic patients with IOL-iris chafing and UGH syndrome. Methods The study retrospectively analyzed patients diagnosed with UGH syndrome presenting at the Ocular Immunology Unit of Reggio Emilia, Italy, from January 2019 to August 2023. Patients’ data were collected. Ophthalmological exams and imaging were performed. The peephole sign in AS-OCT images was evaluated. Statistical analyses were conducted, with a significance level of p ≤ 0.05. Results The study reviewed 22 eyes of 22 patients with UGH syndrome. Four eyes were excluded, leaving 18 patients (8 females, 10 males). Common misdiagnoses included idiopathic anterior uveitis (55.5%) and herpetic anterior uveitis (16.7%). All patients had iris transillumination defects, mostly focal (77.8%). AS-OCT revealed IOL chafing in all the eyes, with peephole sign correlation. More peephole signs occurred with IOL in the sulcus (p-value = 0.08). Conclusion The study recommends AS-OCT for UGH syndrome confirmation and UBM when IOL-iris chafing is not observed on AS-OCT scans.

Cornea and Anterior Segment Parameters and Their Importance in Eye Disease

Corneal and anterior segment parameters (ASP) are valuable in diagnosis and risk assessment of diseases such as glaucoma and keratoconus and it is also an invaluable tool in patient selection and surgical planning of excimer laser refractive surgery. Devices where cornea and anterior segment parameters are measured include Sirius system, Pentacam, Orbscan, Galilei, Anterior Segment Optical Coherence Tomography (ASOCT).

Correlation of anterior segment optical coherence tomography and ultrasound biomicroscopy in congenital corneal opacity

To investigate the correlation between swept-source anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in congenital corneal opacity (CCO). All children with unilateral or bilateral congenital corneal opacities who underwent examination under anesthesia (EUA) and anterior segment optical coherence tomography (AS-OCT) imaging from January 1, 2022, to December 31, 2022, were included. Main outcome measures were corneal and anterior segment evaluation and correlation of UBM and AS-OCT findings. A total of 22 eyes of 15 patients were imaged using both technologies. The age at first EUA ranged from 11 days to 4 years. Different phenotypes were classified based on the clinical examination, UBM, and AS-OCT findings. Fourteen eyes were diagnosed with Peters anomaly, congenital corneal staphyloma was observed in 4 eyes, 2 eyes had coloboma, 1 eye had peripheral sclerocornea, and 1 eye was diagnosed with congenital primary aphakia. AS-OCT and UBM findings were closely correlated in 18 of 22 eyes (82%) but AS-OCT failed to provide detailed information in 4 eyes (18%) where UBM revealed more details. Although AS-OCT offers valuable preliminary data for initial assessment and counseling, it may not consistently provide precise assessments in all cases. Therefore, UBM should be considered for definitive evaluation.

Donor Cornea Storage Temperature: Investigation of the Time Period Immediately Before Cornea Transplantation Surgery

Purpose: Donor cornea storage temperature seems to affect tissue viability; however, the time period between removal from storage and transplant surgery has not been explored. We investigated the possible impact time at room temperature in the operating room may have on endothelial cell density (ECD) and corneal thickness (CT). Methods: In our simulation, transplant-ineligible corneas underwent 1 of 4 room temperature protocols. ECD (by specular microscopy) and CT (by anterior segment optical coherence tomography [OCT]), measured before and after protocols, were used to explore possible effects of time at room temperature. Control group tissue resided at room temperature only long enough for warming and subsequent ECD and CT measurements. Results: Corneas underwent one of the following protocols: 1) 17 (±1) minutes at room temperature (for baseline OCT measurements; n = 13) followed by 23 minutes at 35°C (to facilitate specular imaging, conducted for all 4 protocols), 2) 60 (±1) minutes (1 hour; n = 8) at room temperature, 3) 187 (±1) minutes (approximately 3 hours; n = 7) at room temperature, and 4) 416 (±1) minutes (approximately 7 hours; n = 7). Statistical analysis showed no significant difference in ECD change (P = 0.353) or CT change (P = 0.415) between protocol groups. Controlling for donor age and death-to-preservation time rendered no statistical significance. Conclusions: Time at room temperature did not seem to significantly influence ECD or CT measured soon after warming. Studies exploring ECD postoperatively and long-term graft survival are needed to assess the possible clinical impact of preoperative time at room temperature.

Advancements in keratoplasty: Exploring newer techniques and imaging modalities for enhanced surgical outcomes

Abstract: Keratoplasty, the transplantation of corneal tissue, is a well-established surgical procedure for the treatment of various corneal diseases. Over the years, advancements in keratoplasty techniques have significantly improved surgical outcomes and patient satisfaction. This review article provides an overview of newer techniques and imaging modalities in keratoplasty that have emerged as promising options for corneal transplantation. The article begins with a brief overview of traditional keratoplasty techniques, including penetrating keratoplasty, deep anterior lamellar keratoplasty, Descemet’s stripping automated endothelial keratoplasty (EK), and Descemet’s membrane EK. It then delves into the discussion of newer techniques, including femtosecond laser-assisted keratoplasty, Bowman layer transplantation, and the role of anterior segment optical coherence tomography in keratoplasty. This review article aims to provide ophthalmologists with a comprehensive understanding of the newer techniques in keratoplasty, their advantages, limitations, and clinical outcomes. It emphasizes the importance of individualized treatment planning, considering patient-specific factors, and utilizing advanced imaging modalities to optimize surgical outcomes. The incorporation of newer techniques and imaging modalities in keratoplasty has the potential to revolutionize the field, offering improved visual outcomes, reduced complications, and enhanced patient satisfaction. Continued research and technological advancements will further refine these techniques, paving the way for the future of keratoplasty and improving the quality of life for patients with corneal diseases. We evaluate the currently available literature in this article to provide a comprehensive overview of contemporary surgical and imaging methods in ophthalmology to facilitate additional developments in the field of corneal transplantation.