Segment Spectral-domain Optical Coherence Research Articles

Simultaneous evaluation of iris area and subfoveal choroidal thickness in Fuchs uveitis syndrome

Background/aimsTo simultaneously evaluate iris area (IA) and subfoveal choroidal thickness (SFCT) in eyes with Fuchs Uveitis Syndrome (FUS).MethodsWe prospectively recruited a case series of patients with FUS at our institution, simultaneously measuring IA with anterior segment spectral domain optical coherence tomography (SD-OCT) and SFCT with enhanced depth imaging optical coherence tomography (EDI-OCT). Iris images were analyzed by ImageJ software. We tested the differences in intereye IA and SFCT with the healthy eye (HE) using the Wilcoxon test, and clinical interpretation was controlled by intraclass correlation coefficient (ICC) between two masked specialists.ResultsSixteen patients with unilateral FUS were included. Six were female, and the age range was 37 to 67 (median age 48 years, IQR 41–60). ICC of 98.9%, with a lower confidence interval of 97%. Eyes with FUS had a significant thinning of the total iris median area (p < 0.002), restricted to the temporal and nasal areas compared to the HE (p < 0.01 and < 0.001, respectively). SFCT was also significantly thinner compared to the HE (p < 0.0001). A low correlation was found between iris and choroidal thinning in FUS eyes (rs = 0.21; p = 0.4).ConclusionsThis study found reduced iris area and subfoveal choroidal thickness in eyes with FUS compared to the normal fellow eye.

A simple technique for suprachoroidal space injection of triamcinolone acetonide in treatment of macular edema.

To introduce a simple resistance controlled suprachoroidal space (SCS) injection technique using a disposable 30-gauge needle connected to a 1 mL syringe and evaluate the effectiveness and applicability of this technique in the treatment of macular edema. A total of 20 patients with various types of macular edema were subjected to a resistance controlled SCS injection of triamcinolone acetonide (TA) with a disposable 30-gauge needle connected to a 1 mL syringe. This technique allows the easy and smooth injection of the TA only once the tip of the needle reached the potential SCS which was indicated by the lower resistance on the plunger. The main outcome measures were anterior segment spectral-domain optical coherence tomography (AS-OCT) measurements post-operation immediately and central subfield thickness (CST), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) measurements at 3mo post-operation. AS-OCT examination showed the expansion of the SCS near the injection site immediately after SCS injection. At three months of follow-up, as compared to the baseline, the mean CST was significantly decreased from 535.0±157.24 to 319.55±127.30 µm (P<0.001), the mean BCVA was significantly improved from 1.05±0.41 to 0.73±0.41 logMAR (P<0.001), and the mean IOP was not significantly different, from 15.05±2.54 to 15.85±3.60 mm Hg (P=0.185). Any complication related to the injection procedure including cataract, choroidal and retinal hemorrhage, retinal detachment, or endophthalmitis was not observed in this study. The simple and minimally invasive technique of SCS injection of TA with a disposable 30-gauge needle connected to a 1 mL syringe is useful and applicable for macular edema.

Deep learning model to identify angle dysgenesis on ASOCT images

AbstractAnterior segment spectral domain–optical coherence tomography (ASOCT) is increasingly used in glaucoma patients, primarily to investigate the anterior chamber angle and visualize the trabecular meshwork (TM) and Schlemm's Canal (SC) in‐vivo. The anatomical variability of the drainage angle, TM and SC morphology makes it difficult to distinguish normal from abnormal. Therefore, the interpretation of ASOCT images requires expertise and a deep understanding of the complexity involved in the developmental anomalies of the outflow pathways. While the ASOCT scans can successfully capture the gross changes, they may fail to identify angle dysgenesis in cases where altered extracellular matrix anomalies are subtle enough to get unnoticed by the human eyes of an expert. Deep learning (DL) has demonstrated convincing results and potential in classifying ophthalmic diseases. The integration of high‐resolution ASOCT images trained DL algorithms can further enhance the translational potential of DL‐based classification for angle dysgenesis. Apart from the gross changes in the iridocorneal angle region, the perturbations in TM layers due to associated gene mutations are also captured on ASOCT scans and may be identified by DL algorithms. We have developed DL models, which can identify obscure features of angle dysgenesis in ASOCT scans (ADoA) and validated its performance in eyes with primary open angle glaucoma. Eight hundred ASOCT B‐scans were included, and each image was cropped to extract the iridio‐corneal angle (ICA) area and a TM area to form two datasets. Finally, the total number of images after augmentations in each dataset increased to 8160, divided into training and testing sets for model building. To avoid overfitting, incorporate variability and increase the size of the datasets, 23 different types of augmentation techniques were performed on each image using the CloDSA tool, a freely available package.Three deep learning models were developed for a consensus‐based outcome to identify ADoA objectively. The models performed well on the internal as well as external validation datasets. The model performance on the multiple independent datasets highlights the translational relevance of image‐based diagnostic alternatives in clinical settings, as it has the potential to be deployed for screening patients and their family members for detection of angle dysgenesis in vivo.

In vivo identification of angle dysgenesis

AbstractAnterior segment Spectral domain–optical coherence tomography (SD‐OCT) is being increasingly used in glaucoma patients, primarily to investigate the anterior chamber angle and visualize the trabecular meshwork (TM) and Schlemm's canal (SC) in vivo. With the advent of angle surgery for glaucoma much interest has been generated in the aqueous outflow pathways. Our studies have shown that in vivo imaging of anterior chamber angle with ASOCT can been used to detect gross features of angle dysgenesis in primary congenital glaucoma (PCG), juvenile onset open angle glaucoma (JOAG) and adult onset primary open angle glaucoma (POAG), which has been described either as an absence of SC and/or the presence of abnormal tissue or a hyper‐reflective membrane within angle recess. This membrane is similar to what Barkan had described in PCG and was later described to be an angle cicatrization that portends a poorer success with goniotomy. Absence of development of SC was also shown by Hollander et al to be associated with a severe form of goniodysgenesis while its presence was seen in less severe goniodysgenesis on histopathological studies involving PCG. In fact, angle dysgenesis on ASOCT (ADoA), can be observed even in eyes with gonioscopically normal appearing angles. It is known that gonioscopy provides only a superficial representation of the histopathological anomalies affecting the angle. The presence of a thick compact tissue in the TM samples of Juvenile glaucoma patients has been observed, irrespective of whether they had an apparent goniodysgenesis or not. Hence, what appears to be morphologically normal angle on gonioscopy may harbour dysgenesis of the TM or even the SC. Primary congenital glaucoma, JOAG and adult onset POAG form a spectrum in terms of severity of angle dysgenesis. While most of the PCG eyes have features of ADoA, the same are present in 40% of JOAG eyes and in up to 35% of adult onset POAG. The size of the SC has also shown to be decreased in patients with adult‐onset open angle glaucoma based on in vivo OCT studies. We also present interesting observations of angle dysgenesis in fellow eyes of children with unilateral PCG.

A comparison of central corneal thickness measured using noncontact methods and ultrasonic pachymetry.

The aim of this study is to compare central corneal thickness (CCT) measurements in healthy eyes using ultrasonic pachymetry (UP) with values obtained using anterior segment spectral domain optical coherence tomography (SD-OCT), the Scheimpflug camera system, and noncontact specular microscopy. One hundred and twenty-five eyes of 117 healthy individuals (56 women, 61 men) were included. All patients underwent consecutive CCT measurement with UP, the Scheimpflug camera, anterior segment SD-OCT, and specular microscopy. The four devices could be read. Measurements from the four devices were classified in pairs and compared using the paired t-test. Relations between the devices were analyzed using the Pearson test. An alpha error level of P < 0.05 was regarded as statistically significant. The mean age of the healthy individuals included in the study was 34.75 ± 14.55 years (20-76). Mean CCT values were 541.21 ± 29.24 μm with UP, 539.26 ± 29.27 μm with the Scheimpflug camera system, 532.21 ± 29.53 μm with SD-OCT, and 534.45 ± 29.20 μm with specular microscopy. The differences in measurements at the paired t-test were statistically significant (P < 0.001 for all). However, measurements using the four devices exhibited significant mutual correlation (P < 0.001 for all). CCT can be measured using different devices. Noncontact methods have now begun replacing UP, regarded as the gold standard. Although CCT values obtained from different devices were correlated, the difference between these measurements was statistically significant. Therefore, the same device should be used for measurement in the diagnosis and follow-up of diseases such as corneal ectasia and glaucoma where corneal thickness is important.

The depigmentation degree of iris pigment epithelium in pseudoexfoliation syndrome

BackgroundTo compare the optical density of iris pigment epithelium (ODIPE) and iris stromal thickness (IST) measurements in patients having pseudoexfoliation syndrome (PXS) and age-gender matched participants. MethodsThis is a cross-sectional study. Patients with PXS were enrolled in the study group. Age and gender-matched healthy subjects with no evidence of PXS were recruited as controls. After a comprehensive ophthalmological evaluation, the anterior segment images were acquired using anterior segment spectral-domain optical coherence tomography (AS SD-OCT). The acquired pictures were further analyzed using the ImageJ program. Two investigators measured the ODIPE and the IST of the subjects, and the repeatability and reproducibility were checked. SPSS program was used for statistical analysis. ResultsThe PXS group was comprised of twenty-two eyes (n = 22 patients), and the control group contained twenty-six eyes of 26 age and gender-matched healthy subjects. The mean temporal ODIPE of the study group was found to be decreased significantly in comparison to the mean temporal ODIPE of the control eye (p = 0.018). Both the mean nasal (N) and temporal (T) ISTs of the PEX eyes were thinner than the control eyes (p = 0.006 and p = 0.002, respectively). The mean baseline IOP was found to significantly negatively correlate with the ODIPE in the PEX group at both N and T sides (r = -0.531, p = 0.011 and r = -0.685, p < 0.001, respectively). ConclusionThe pupillary margin IPE was found more depigmented, and the mean N and T IST were significantly thinner in the PEX group by comparison with the age-gender matched healthy controls. The mean baseline IOP was negatively correlated with the pupillary margin's IPE pigmentation degree in patients with PXS.

Korneal Çapraz Bağlama Tedavisi Sonrası Epitel Kalınlığın Değişimi: Retrospektif Bir Araştırma

Objective: To assess the corneal epithelial remodeling after corneal crosslinking (CXL) and to investigate the relation between topographic parameters and epithelial thickness change. Material and Methods: Sixty-three eyes of 43 keratoconus patients were included in this retrospective study. Keratometry (K) and elevation data were assessed by Scheimpflug topography and corneal and epithelial thickness profile was obtained by anterior segment spectral-domain optical coherence tomography pre-operatively and at the 1st, 6th and 12th months after CXL. Results: Significant decreases were observed in mean K (p=0.014), maximum K (p=0.049), and mean central corneal thickness (p<0.007) after CXL. Superior corneal epithelial thickness was significantly thinner (p<0.001) and the difference between the minimum and maximum epithelial thickness was less at the post-operative first month and didn't change significantly afterwards. Standard deviation of epithelial thickness across the central 5 mm region statistically decreased in the follow-up period (p=0.008). Conclusion: Significant regularization of the epithelial thickness profile was seen in one year after epithelium-off CXL. Demonstrating the normalization of the corneal epithelium and understanding its impact on the post-operative healing process might contribute to the optimization of treatment protocols.

In Vivo Analysis and Comparison of Anterior Segment Structures of Both Eyes in Unilateral Herpetic Anterior Uveitis

ABSTRACT Purpose: To compare the Schlemm’s canal area (SCA) and to define iris features in patients with unilateral herpetic anterior uveitis (HAU) by using anterior segment spectral-domain optical coherence tomography (AS SD-OCT). Methods: Unilateral HAU cases that had been in complete remission for ≥ 3 months were included. Two investigators analyzed the iris features of HAU. SCA in both healthy (N), and affected eyes (HAU) were compared. Results: The mean age of the participants (n = 22) was 36.3 ± 15 (17–70) years. The mean nasal and temporal (n-t) SCA was measured as 10,844 ± 4806 µm2 and 8,772 ± 3138 µm2 in HAU in comparison with 10,200 ± 4,824 µm2 and 10,045 ± 3,889 µm2 in N, respectively (p = .47 and p = .12, respectively). The most common iris features were the sectoral iridoplegia (100%) on biomicroscopy and the disorganization of the iris layers (DIL) (77%) on AS SD-OCT images. Conclusion: SCA found similar on both sides. DIL is the most common iris feature of affected eyes.

Reproducibility, and repeatability of corneal topography measured by Revo NX, Galilei G6 and Casia 2 in normal eyes.

To test the repeatability and reproducibility of the topography module in posterior segment spectral domain optical coherence tomography with Revo NX (new device) and to compare keratometry values obtained by a Scheimpflug tomography (Galilei G6) and a swept source OCT (Casia 2). In this prospective study, healthy subjects with nonoperated eyes had their central corneal thickness (CCT), anterior and posterior K1/K2 corneal power measured with the new device. Two operators made 6 measurements on the new device to check intraobserver repeatability and reproducibility, and measurement on Casia 2 and Galilei G6. Bland-Altman plots were used to assess the agreement between the devices for each analyzed variable. 94 eyes (94 patients) were studied. All devices produced significantly different mean CCT, the highest for Galilei 569.13±37.58 μm followed by Casia 545.00 ±36.15 μm and Revo 537.39±35.92 μm. The mean anterior K1 was 43.21 ± 1.37 for Casia 2 43.21 ± 1.55 for Revo NX and 43.19 ± 1.39 for Galilei G6, and the differences were insignificant p = 0.617. The posterior K1 for Revo NX was -5.77 ± 0.25 whereas for Casia 2 it was -5.98±0.22 and for Galilei G6-6.09±0.28 D p< 0.0001. The Revo NX showed intraclass correlation coefficient ranging from 0.975 for the posterior K2 surface, and 0.994 for anterior K1 and 0.998 for CCT. Revo NX is independent of the user and offers a high level of repeatability for the anterior and posterior cornea. The wide range of differences between the devices suggests they should not be used interchangeably.

Tear Film Instability and Meibomian Gland Dysfunction Correlate with the Pterygium Size and Thickness Pre- and Postexcision in Patients with Pterygium.

Purpose This study aimed to evaluate the effects of excision on dry eye and meibomian gland dysfunction (MGD) in individuals with pterygium, before and after surgery. It also aimed to investigate how these effects correlate with the size and thickness of the pterygium. Subjects and Methods 63 eyes from 63 patients with primary nasal pterygium and 45 eyes from 45 healthy volunteers without ocular pathologies were enrolled in this study. 63 eyes from 63 patients underwent pterygium surgery. ImageJ software was used to calculate the pterygium size based on images of the anterior segments. Anterior segment spectral domain optical coherence tomography (SD-OCT) was performed preoperatively to measure the thickness of the pterygium 1 mm anterior to the nasal scleral spur. The ocular surface disease index (OSDI), Schirmer I Test (SIT), and MGD grade were used to evaluate the eyes, and the eyes were imaged using the noninvasive keratograph average tear film breakup time (NIBUTav), tear meniscus height (TMH), meiboscore, and lipid layer grading tools of the Oculus® Keratograph 5M, preoperatively and at 1, 3, and 6 months postoperatively. Results The OSDI, NIBUTav, lid margin abnormality, meiboscore, and lipid layer grading values differed significantly in the pterygium patients in comparison with the controls (p < 0.01 for all scores). However, the SIT and TMH values were unchanged between the two groups (all p > 0.05). Multivariate regression analysis demonstrated that the NIBUTav, meiboscore, and lipid layer grading score was significantly correlated with the pterygium parameters, such as size and thickness. The postoperative OSDI, NIBUTav, lid margin abnormality, and lipid layer grading values improved significantly (p < 0.05 for all scores). The SIT, TMH, and meiboscore results did not differ significantly between the pre- and postoperative values (p > 0.05). Among the conventional and automated indexes, at 1 month postoperatively, SIT and TMH were significantly correlated with the pterygium parameters, but no correlation was observed at 3 and 6 months postoperatively. The OSDI, NIBUTav, meiboscore, and lipid layer grading values at 1, 3, and 6 months postoperatively were significantly correlated with the pterygium parameters. Conclusion Abnormal tear film and meibomian gland (MG) function improved following pterygium excision in the patients with primary pterygium, which was associated with uncomfortable ocular symptoms. Pterygium parameters, such as size and thickness, correlated with the dry eye and MGD indexes in patients pre- and postoperatively, potentially offering a novel strategy for clinical implementation of pterygium excision surgery.

Repeatability and reproducibility of optical biometry implemented in a new optical coherence tomographer and comparison with a optical low-coherence reflectometer

To examine the repeatability and reproducibility of biometry provided by a new anterior-posterior segment spectral-domain optical coherence tomography (SD-OCT) device (Revo NX) and compare it with that provided by a validated optical low-coherence reflectometry (OLCR) biometer (Lenstar LS 900). Hygeia Clinic, Gdańsk, Poland. Prospective evaluation of diagnostic test. The axial length (AL), lens thickness (LT), central corneal thickness (CCT), and anterior chamber depth (ACD) (corneal epithelium to lens) were measured in eyes of volunteers. Two skilled operators obtained 3 measurements in random order with the SD-OCT device. Repeatability was calculated for each observer, while reproducibility was assessed by a change in observer. To compare agreement between the SD-OCT device and OLCR device, the first observer took 3 measurements with both devices. The study evaluated 63 eyes of 63 volunteers. The mean AL measurement (+0.11mm±0.02 [SD]) and mean ACD measurement (0.05±0.04mm) were significantly higher with the SD-OCT device than with the OLCR device; the CCT measurements did not differ between the devices. A very strong correlation was found for all parameters, while Bland-Altman analysis showed narrow 95% limits of agreement for AL (0.06 to 0.15mm), ACD (-0.02 to 0.12mm), LT (-0.23 to 0.17mm), and CCT (-7.83 to 6.17μm). The new SD-OCT device provided repeatable and reproducible AL, ACD, LT, and CCT measurements. The results with the SD-OCT device showed strong correlations with those obtained with the OLCR device. However, the AL and ACD measurements of the 2 devices cannot be considered interchangeable.

Characterization of deeply embedded corneal foreign bodies with anterior segment optical coherence tomography.

The purpose of the study was to describe findings demonstrated by anterior segment spectral domain optical coherence tomography (AS-OCT) in various types of deeply embedded corneal foreign bodies. In this experimental study, an ex vivo model of calf eyes was used and seven different foreign bodies were deeply embedded in the cornea, consisting of five different materials: glass, plastic, metal, wood, and pencil graphite. The eyes were photographed and then scanned by AS-OCT. The images were analyzed to determine distinguishing characteristics for each material. Various materials presented unique characteristics in AS-OCT. The opaque materials (pencil graphite, metals, and wood) demonstrated a hyper-reflective anterior border, whereas the posterior border signal could not be clearly identified due to the shadowing effect. Moreover, a chain of signals was characteristic of both pencil graphite and metals though a "mirroring effect" was unique for metals. Wood, as an opaque material, appears as a hyper-reflective mass with a spectrum of penetrability depending on the degree of concentration. Transparent materials demonstrated hyper-reflective sharp borders when surrounded by air or fluid, as opposed to when being embedded purely in the corneal stroma. This study shows that AS-OCT was used to systematically define a novel set of distinguishing characteristics specific to various materials extruding from the cornea, fully embedded in the cornea, and intruding into the anterior chamber. Hopefully, the described characteristics of each material can aid clinicians in diagnosing the type of the material embedded and the depth of its involvement in ocular injury.

Comparison of central corneal thickness measurements with standard ultrasonic pachymetry and optical devices

BackgroundTo compare the repeatability and agreements of central corneal thickness measurements of healthy individuals obtained by Scheimpflug‐Placido topographer (Sirius), anterior segment spectral domain optical coherence tomography (Spectralis) (AS‐OCT), optical biometry (AL‐Scan) and ultrasonic pachymetry.MethodsSixty‐four eyes of 32 subjects with no ocular or systemic diseases were included in this study. Central corneal thickness measurements performed with Sirius, AS‐OCT, optical biometry AL‐Scan and ultrasonic pachymetry were compared. Bland–Altman analysis was used to demonstrate agreement between methods. Intra‐examiner repeatability was assessed by using intraclass correlation co‐efficients (ICCs).ResultsSixty‐four eyes of 32 patients were enrolled (25 male and seven female). The mean age was 23.8-years (range 21–28-years). The mean central corneal thickness was 560.8 ± 37.2 μm, 528.8 ± 32.0 μm, 546.4 ± 33.8 μm, 543.4 ± 35.8 μm for the ultrasonic pachymetry, optical biometry AL‐Scan, Sirius and AS‐OCT values, respectively. The thickest mean central corneal thickness (560.8 ± 37.2 μm) was obtained from ultrasonic pachymetry. The thinnest mean central corneal thickness (528.8 ± 32.0 μm) was obtained from optical biometry AL‐Scan. All four modalities of central corneal thickness measurements correlated closely with each other. Intra‐examiner repeatability was excellent for all devices with ICCs > 0.90.ConclusionsIn conclusion, although measurements obtained by various methods correlate well, the measurements are not directly interchangeable. Between ultrasonic pachymetry and the three optical instruments tested, significant diferences can be seen. Therefore, the same imaging method should be used in corneal thickness follow‐ups.

Multimodal Assessment of Corneal Erosions Using Optical Coherence Tomography and Automated Grading of Fluorescein Staining in a Rabbit Dry Eye Model.

PurposeTo evaluate the potential use of anterior segment spectral domain optical coherence tomography (AS-SD-OCT) combined with an automated grading of fluorescein staining for assessment of corneal erosions in a rabbit short-term dry eye model.MethodsTwenty-one New Zealand white rabbits were anesthetized and eyes were kept open for 140 minutes to induce acute corneal desiccation. Rectangular scans of the cornea were performed using Spectralis AS-SD-OCT. Total corneal thickness, corneal epithelial thickness, and the percentage of epithelial erosion area (PEEA) were evaluated. Corneas were stained with fluorescein and graded automatically using EpiView and semi-automatically using ImageJ. Spearman's rank-order correlations were calculated to compare the AS-SD-OCT PEEA and the two corneal staining scores.ResultsEye desiccation resulted in corneal epithelium erosions that covered 0.67% to 14.2% of the central cornea (mean ± SD: 3.95% ± 3.2%) by AS-SD-OCT. The percentage of corneal area positively stained with fluorescein ranged from 0.24% to 38.01% (mean ± SD: 12.24% ± 9.7%) by using ImageJ, correlating with the AS-SD-OCT PEEA (Spearman's ρ, 0.574; P = 0.007). The EpiView score ranged from 0.5 to 10.17 and was better correlated with the AS-SD-OCT PEEA score (Spearman's ρ, 0.795; P = 0.000017).ConclusionsOur study suggests that multimodal analysis of AS-SD-OCT and grading of fluorescein staining using EpiView software may enable quantitative assessment of corneal epithelial erosions in a rabbit short-term dry eye model.Translational RelevanceThis multimodal imaging analysis may be applied for evaluation of superficial punctate keratitis associated with dry eye.

Anterior Segment Biometry Using Spectral Domain Optical Coherence Tomography

AbstractBackground: AS-OCT allows a non-contact examination with high resolution imaging of the anterior segment of the eye of human. It enables assessment and documentation of the condition of the eye's anterior segment.Aim of Study: Evaluation of Anterior Segment Optical Coherence Tomography (AS-OCT) in quantitative analysis of the anterior segment of the eye. Analysis of association between Central Corneal Thickness (CCT), Corneal Epithelial Thickness (CET) and corneal radius of curvature (CC) meas-ured by OCT in relation to other parameters; age, sex, refraction and Intra Ocular Pressure (IOP).Patients and Methods: The present study included 100 normal eye of 100 hundred patients aged from 20:60 years. CCT, CET and radius of CC were measured using anterior segment Spectral Domain Optical Coherence Tomography (SD-OCT) (3D OCT-2000 (Topcon Corp., Tokyo, Japan)). IOP was measured using Goldman applanation tonometer. Measurements of refractive status were detected by autore-fractor and then confirmed by retinoscopy and spherical equivalent was calculated of astigmatic patients.Results: Total number of 100 eye were evaluated for the study. 34 eyes were emmetrope, 34 eyes were myopes and 32 eyes were hypermetropics. The CCT average was 541.62mm (SD ±21. 11). This study showed no statistically significant difference between CCT in myopes, hypermetropes and em-metropes). Mean IOP was 15.65mmHg (SD ±1.56). The correlation between IOP and CCT was highly significant (r= 0.867; p<0.001). The CET average was 54.80 (SD ±2.68). The study has shown the positive relation between CET and CCT. The mean radii of corneal curvature was vertically 7.61 (SD ±0.27) and horizontally was 7.61 (SD ±0.25). We found a statistically relation between error of refraction and corneal radius of curvature. Eyes with more myopic refractive error tend to have steeper corneas with less radii of curvature on controversy with hypermetropic eyes. No correlation between age or sex to all the above.Conclusion: This study has shown that CCT has no cor-relation with degree of refractive error. Whereas there is significant correlation between CCT and IOP and CET as well. The study also has shown that there were no associations between corneal radius of curvature and IOP. However, myopic eyes shows tendency for smaller radii of curvature whereas in hypermetropic ones the radii of curvature tend to be longer. There was no significant relation between age and sex and any parameter of the study. Our findings highlight the value of spectral domain AS-OCT measurements as a standard tool in anterior segment analysis.

Characterization of Corneal Donor Tissue Lesions by Anterior Segment Optical Coherence Tomography Compared With Eye Bank Technician Slit-Lamp Examination.

To compare anterior segment spectral-domain optical coherence tomography (OCT) with eye bank technician slit-lamp examination (SLE) in characterizing lesions in donor corneas. Twenty-nine donor corneas identified by eye bank technicians to have opacities or lesions potentially representing pathologic findings affecting the stroma were evaluated through the use of technician SLE, SLE photography, and OCT. Technicians were tasked with describing the lesion, estimating the lesion depth, and photographing their SLE findings. A masked grader evaluated the OCT images and measured the lesion depth using customized software. The lesions identified on OCT were then compared with those identified on SLE. A total of 37 lesions were detected on SLE; 25 of the 37 lesions identified on SLE were matched to a lesion on OCT. SLE and OCT depth measurements were statistically significantly different (P = 0.0042, mean difference 4.8% ± 6.5%), and OCT graded lesions as slightly deeper. Of the 12 out of the 37 lesions that were noted on SLE (but not identified on OCT), these included 2 central and paracentral anterior stromal lesions (OCT showed loose epithelium), 5 peripheral anterior stromal lesions, and 5 corneas with LASIK. Our study highlights both advantages and limitations of OCT compared with technician SLE in the evaluation of donor corneal tissue. Although OCT may miss some peripheral lesions and LASIK scars that are identifiable on SLE, OCT's depth resolution is helpful in differentiating whether shallow anterior opacities actually extend deeper into the stroma or are confined superficially to the epithelium.

Tear meniscus evaluation after microkeratome laser in situ keratomileusis, femtosecond laser and femtosmile laser techniques using anterior segment optical coherence tomography.

PurposeThe purpose of this study was to compare the effects of three different corneal refractive surgeries: microkeratome laser in situ keratomileusis (LASIK), femtosecond laser in situ keratomileusis (FS-LASIK) and femtosecond small incision lenticule extraction (FS-SMILE) on 6-month postoperative stability of tear film to provide a basis for selection of operative procedures.Patients and methodsThis is a prospective, randomized, comparative study that included 90 eyes of three equal groups of patients. Each group was subjected to a different laser technique: LASIK, FS-LASIK and FS-SMILE. Using anterior segment spectral domain optical coherence tomography (AS-SD-OCT), the lower tear meniscus parameters were measured preoperatively and 1 week, 1 month, 3 months and 6 months postoperatively. Changes were studied and compared.ResultsThere was a statistically significant difference in tear meniscus height (TMH) between FS-SMILE and FS-LASIK in the first week (P = 0.003) and first month (P = 0.002) with no statistically significant difference between both techniques at 3 and 6 months postoperatively. In FS-SMILE, TMH returned to 95% of its preoperative level after 1 month. There was no statistically significant difference in TMH between FS-LASIK and microkeratome LASIK techniques after 1 week and 1 month, but there was a statistically significant difference between both techniques in 3 months (P = 0.019) and 6 months (P = 0.032). Tear meniscus area (TMA) showed no statistically significant difference between FS-SMILE and FS-LASIK at all points of follow-up, but there was a statistically significant difference between both techniques and microkeratome LASIK (all P < 0.05). Microkeratome LASIK parameters failed to reach the preoperative level till 6 months.ConclusionEarly recovery of the lower TMH can be achieved as early as 1 month post-operatively with the FS-SMILE technique compared to FS-LASIK and microkeratome LASIK techniques.

Retinal and optic nerve degeneration in \u03b1-mannosidosis

Backgroundα-mannosidosis is a rare, autosomal-recessive, lysosomal storage disease caused by a deficient activity of α-mannosidase. Typical symptoms include intellectual, motor and hearing impairment, facial coarsening, and musculoskeletal abnormalities. Ocular pathologies reported previously were mainly opacities of the cornea and lens, strabismus, and ocular motility disorders. However, retinal and optic nerve degeneration have been rarely described.MethodsWe report ocular findings of 32 patients with α-mannosidosis. We particularly concentrated on retinal abnormalities which we supported by posterior segment examination, fundus photography, and Spectral-Domain optical coherence tomography (SD-OCT) imaging.ResultsTapeto-retinal degeneration with bone spicule formations in the peripheral retina or macular changes were seen in three patients (9.4%) on funduscopy; of these, two with optic nerve atrophy. Eight retinal images could be obtained by OCT or fundus photography; of these, six showed thinning of the outer retinal layers on OCT. Overall, optic nerve atrophy was seen in six patients (18.8%); of these, four with partial atrophy. Two patients had partial optic nerve atrophy with no retinal abnormalities on funduscopy. Cataract was seen in two (6.3%), corneal haze also in two patients (6.3%). Six patients (18.8%) had manifest strabismus, four (12.5%) nystagmus, and in five patients (15.6%) impaired smooth pursuit eye movements were seen.ConclusionOcular pathologies are not exclusively confined to opacities of the cornea and lens or strabismus and ocular motility disorders but tapeto-retinal degeneration and optic nerve atrophy may be a common feature in α-mannosidosis. OCT technology helps detecting early outer retinal thinning which can progress with age and potentially leads to vision loss over time.

The effect of PRK on corneal epithelium thickness and pachmetry in treatment of myopia.

In order to facilitate the corneal stromal ablation in photorefractive keratectomy the epithelium is removed so corneal repair associated with changes in epithelium and stroma. To study the corneal epithelial thickness and pachymetry profile changes after photorefractive keratec­tomy (PRK) for myopia. Retrospective analysis of the postoperative corneal epithelial thickness and pachymetry profile changes in 22 eyes of 12 patients treated with PRK for myopia or myopic astigmatism. Corneal and epithelial thickness maps within the central 6 mm were obtained by anterior segment spectral-domain optical coherence tomography (SD-OCT) preop­eratively and at 3 months postoperatively. Correlations between pachymetry,epithelial thickness changes and the amount of correction,were analyzed.Compared to preoperative values,the central 2 mm and the paracentral 2 to 5 mm zone epithelium was 1 ± 2.85 and 1 ± 3.11 μm thicker,respec­tively,at 3 months postoperatively (P &lt;.05). The spheri­cal equivalent (SE) changed from-2.80 ± 2.028 diop­ters (D) preoperatively to -0.40 ± 0.42 D at 3 months postoperatively. Females show greater postoperative epithelial thickening, 2.6 ± 3.77 μm,than males,0.34 ± 1.98 μm. There was a trend toward greater epithelial thickening with a larger amount of programmed SE correction, and thinner preoperative epithelium. No correlation between epithelial thickness change and postoperative change in refraction was detected.Negative correlation between between age, refractive error,with the pre and post-operative pachymetry. In general female pachymetry reading is higher than it in male.The corneal epithelial thickness in­creased after PRK up to 3 months postoperatively. It was affected by the amount of myopia treated, gender, and preoperative epithelial thickness. The refractive outcomes did not affected by the postoperative epithelial thickening. Negative correlation between between age, refractive error, with the pre and post-operative pachymetry. In general female pachymetry reading is higher than it in male.

Evaluation of Long-term Anatomic Changes Following Canaloplasty With Anterior Segment Spectral-domain Optical Coherence Tomography and Ultrasound Biomicroscopy

To analyze long-term structural changes in conjunctiva, sclera and Schlemm canal (SC) with anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) following uncomplicated canaloplasty. Fifteen patients with planned canaloplasty and no intraoperative complications were included in this prospective study. AS-OCT images were acquired at 1, 3, 6 months and at a long-term time point (20±4.9 mo) postsurgery. UBM images were acquired at 3, 6 months and long-term after canaloplasty. The surgical site was evaluated for the presence of SC, transscleral filtration, a scleral lake, and the visibility of intra-Schlemm sutures. The SC's height and width were measured at the 3 and 9 o'clock limbus position. Following canaloplasty, the intraocular pressure was successfully reduced from 23.43±5.52 to 12.6±1.78 mm Hg (P<0.0001) at the final control visit. Topical medication was reduced from 2.9±1.1 to 0.4±0.6 over the same period. SC's increase in height was higher than that in width at the last visit (height: +351%, P=0.0004, width: +144%, P=0.002). With the UBM the SC was easily identifiable by the reflection of the tractions sutures in 75% of the patients at the last visit. Transscleral filtration was detectable in 42% of the patients at the last visit using AS-OCT and a scleral lake was still detectable by OCT in 25% of the patients and even in 42% of the patients by UBM. Persisting anatomic changes of SC, a transscleral filtration and a scleral lake can be recorded by AS-OCT and UBM long-term after successful canaloplasty.