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Purpose: To discuss the novel swept?source anterior segment optical coherence tomography (SS?ASOCT)?guided surgical approach in slipped medial rectus muscles. Methods: Prospectively (between February 2020 and July 2022), six patients with a clinical suspicion of slipped medial rectus muscle were recruited. After complete ophthalmic and orthoptic evaluation, the missing medial rectus muscle is screened using Anterior Segment Optical Coherence Tomography (ASOCT). In presence of a traceable muscle, its morphology, depth, and distance from a fixed anatomical landmarks were noted; in its absence, the status of other recti was noted. Intraoperatively, the features were confirmed and the intended intervention was performed. Results: The mean age of six patients was 25.66 ± 9.72 years, two with surgical trauma and four with penetrating trauma (66.66%). In five patients, the ASOCT traced the slipped medial rectus muscle successfully (83.33%); intraoperatively, the same was confirmed (within 1–2 millimeters) with favorable outcomes. ASOCT made a significant contribution in all subjects by reducing the number of interventions and muscle surgeries. Conclusions: In eyes with slipped medial rectus muscle, especially those which are within a finite distance from the angle can be traced using ASOCT. This approach impacts the outcomes in many ways
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Purpose: To report anterior?segment optical coherence tomography (ASOCT) characteristics of different types of corneal and anterior chamber (AC) foreign bodies (FBs) and their usefulness in diagnosis and management. Methods: This is a retrospective descriptive clinical study involving 11 eyes of 11 patients who presented at the outpatient department of a tertiary ophthalmic care center from January 2017 to January 2022. All patients had a diagnosed or suspected corneal FB. All participants underwent a comprehensive ophthalmological examination, followed by slit?lamp photography and ASOCT. FB removal was done where required by an external, internal, or combined approach. Results: The mean age of patients was 28.2 (7–53) years. Ten were male, and one was female. Seven patients had a definitive positive history of injury; in one, there was a history suggestive of trauma, one had the post?operative complication of scleral buckling surgery, and two patients had a history of insect fall in the eyes. Three patients had acute, four had sub?acute, and four had chronic presentations. Descemet’s membrane (DM) breach was suspected in three cases of deep FB, which was later confirmed on ASOCT. In two cases, DM was presumed to be intact clinically, but ASOCT showed an AC penetration. The FB was removed in seven patients, one via slit?lamp, one via an external approach, two via an internal approach, and three via a combined approach. Conclusion: ASOCT facilitates non?invasive rapid imaging of ocular tissue at various depths, provides an accurate assessment of FB characteristics, and thereby serves as an additional tool in our armamentarium for diagnosis and management of deep corneal and AC Fbs
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Purpose: To correlate and analyze the pattern of the visual field (VF) defects by perimetry and anterior chamber angle parameters by AS-OCT in primary angle-closure glaucoma (PACG) across varied severity levels on presentation to a tertiary eye care center. Methods: This was a cross-sectional study, which included 323 eyes of clinically diagnosed cases of PACG. Glaucoma severity was categorized according to mean deviation (MD) as mild (-6.00 dB or more), moderate (-6.01 to -12.00 dB), and severe (-12.01 to -30.00 dB). AS-OCT measured the nasal (N) and temporal (T) angle opening distance at 500 ?m (AOD 500) and 750 ?m (AOD 750), anterior chamber angle (ACA), lens vault (LV), and anterior chamber width (ACW). The VF severity was then correlated with the AS-OCT parameters using statistical analysis. Results: The mean age ± standard deviation (SD) of the patients included in the study was 56.03 ± 8.6 years, with a 1:1.2 gender ratio. The number of eyes with mild, moderate, and severe VFs were 140 (43.3%), 88 (27.24%), and 95 (29.41%), respectively. There was no statistically significant correlation in the mean anterior chamber angle parameters (AOD 500, AOD 750, ACA 500, ACA 750, LV, ACW, and axial length (AL)) among the groups. However, the correlation between AOD 500 and LV thickness was found to be significant (P = 0.0000) with a negative Spearman’s rank correlation coefficient (r = -0.3329). Conclusion: The ACA parameters obtained by AS-OCT along the horizontal axis after elimination of pupillary block by laser peripheral iridotomy do not correlate and cannot be used to assess the disease severity of PACG
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Background: AS-OCT is a noncontact imaging device that provides the detailed structure of the anterior part of the eyes. The Objectives In this review, the author will discuss the clinical applications of AS-OCT in the scleral contact lens fittings.Material & Methods:Pre-Scleral lens fit and post fit ASOCT done on 30 patients to assess the normal fitting and compare it with the slit lamp evaluation.Results:ASOCT gives a Quantitative measurement of the fit.Conclusions:ASOCT comes out as a helpful tool for beginners particularly for a good assessment of a contact lens fit. The author also presents some interesting cases demonstrated via AS-OCT.
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Purpose: To compare the corneal epithelial thickness among various age groups of normal Indians with 9?mm?wide optical coherence tomography scans. Methods: This cross sectional, observational study recruited patients in the age groups of 5–20 years (group 1), 21–35 years (group 2), 36–50 years (group 3), and more than 51 years (group 4). They underwent a detailed ophthalmic examination and were excluded if found to have any ocular surface or intraocular disease (except cataract and refractive error), undergone any ophthalmic surgery, corneal topography changes suggestive of corneal ectasias, or been continuously using any topical medication in either eye for a period of 3 months or more with the last instillation being within 1 month of inclusion in the study. Corneal epithelial thickness (CET) was measured using anterior segment optical coherence tomography (AS?OCT). The CET data from 25 sectors in each eye were analyzed for each age group. Results: There were 71 subjects in group 1, 76 subjects in group 2, 59 subjects in group 3, and 57 subjects in group 4. The mean (± standard deviation) ages in the groups 1, 2, 3, and 4 were 14.04 ± 5.10, 26.63 ± 4.71, 42.66 ± 3.92, and 61.65 ± 7.47 years, respectively. The central corneal thickness in all age groups was comparable. Maximum variance in CET parameters was seen in superior cornea. Conclusion: Central corneal thickness remains fairly stable over various age groups. The maximum variance in CET over age is seen in superior cornea. The findings from the Indian population correlate well with racially and geographically distinct subjects.
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@#AIM: To evaluate the changes in corneal epithelial thickness in corneal grafts following penetrating keratoplasty(PK)using anterior segment optical coherence tomography(AS-OCT), and to determine the role of epithelial thickness mapping in the early detection of graft rejection.<p>METHODS: This prospective comparative observational study included 20 patients(20 eyes)who underwent PK as study group and 16 patients(16 eyes)as control group. Corneal epithelial thickness mapping using AS-OCT was performed at 2wk, 1 and 3mo postoperatively. The parameters of epithelial thickness and distribution at the 3mo were compared to 16 patients(16 eyes)with allograft rejection following PK.<p>RESULTS: There was significant decline in the superior, inferior, maximum, and minimum epithelial thickness values of the study group at 1mo compared to 2wk(<i>P</i>=0.0004, 0.0001, 0.0001, 0.04 respectively)with no significant differences at 3mo compared to 1mo(<i>P</i>=0.4, 0.1, 0.8)respectively. Percentage of reduction in epithelial thickness was significantly higher than that of stromal thickness at 1mo compared to 2wk(<i>P</i>=0.04). The epithelial thickness maps showed a similar pattern of epithelial thickness distribution in the study group and in the rejection group showing considerable corneal edema. However, the allograft rejection group showed irregular pattern of epithelial thickness distribution in patients showing relatively higher central corneal thickness(CCT)as measured by pachymetry map.<p>CONCLUSION: Quantitative assessment of graft epithelial remodeling following PK shows early changes that contribute to significant corneal graft thickness changes. Changes in corneal epithelial thickness and pattern of distribution could be used as an indicator for corneal graft rejection.
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Purpose: To determine the comparability of anterior chamber biometric measurements in primary angle closure disease (PACD) patients using two commercially available anterior segment optical coherence tomography machines (ASOCT): Visante and Casia. Methods: This was a cross-sectional observational study, which included clinically, diagnosed cases of PACD. Anterior segment biometric measurements were done using Casia and Visante ASOCT. Parameters studied were central corneal thickness (CCT), anterior chamber depth (ACD), nasal (N) and temporal (T) angle opening distance at 500 ?m (AOD500) and 750 ?m (AOD750), and N and T trabecular iris space area at 500 ?m (TISA500) and 750 ?m (TISA750). Results: Total 36 PACD patients (72 eyes) with average age of 59.48 ± 7.95 years were recruited, out of which 25 were females (69.44%) and 11 males (30.56%). The mean measurements of CCT, ACD, AOD500, and TISA on Casia and Visante machines were 522.5 ± 34.75 ?m and 539.55 ± 29.56 ?m (P = 0.00); ACD- 2.144 ± 0.38 mm and 2.133 ± 0.39 mm (P = 0.487); AOD500-0.27 ± 0.16 ?m and 0.21 ± 0.10 ?m (P = 0.04); and TISA500-0.100 ± 0.07 ?m and 0.063 ± 0.03 ?m (P = 0.00), respectively. A statistically significant difference was noted in CCT, N and T AOD, and TISA. A good corelation for ACD and CCT (ACD = 0.9816 and CCT = 0.772) only were noted between the two machines. The Bland-Altman plot analysis of different parameters between two machines has revealed good agreement of measurement of ACD and CCT but poor agreement for rest of the parameters. Conclusion: It is advisable not use the two machines interchangeably because of the wide limits of agreement and poor correlation of angle measurement values of Casia and Visante ASOCT.
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Objective@#To determine the presence of iridotrabecular contact (ITC) and compare the changes in anterior chamber angle (ACA) measurements in room lights-on and lights-off conditions using the anterior segment optical coherence tomography (AS-OCT) in eyes diagnosed as primary angle closure suspects (PACS) by gonioscopy.@*Methods@#This is a retrospective review of 144 eyes of 79 patients (70 females, 9 males) with PACS. All eyes were imaged using the Visante® time-domain AS-OCT (Carl Zeiss Meditec, Dublin, CA). Each eye was imaged twice; the first scan was done with the room lights on followed by a second scan done after turning the room lights off for 2 minutes. The principal outcome measure was the presence of ITC in either lighting condition. Other angle metrics that were assessed included anterior chamber depth (ACD), angle opening distance (AOD), trabecular-iris space area (TISA), and scleral spur angle (SSA). Presence of ITC and differences in the angle metrics between the 2 lighting conditions were then analyzed using the t-tests and logistic regression.@*Results@# ITC was present in 36.8% (53) of the study eyes. Twenty percent (20%) of the study eyes (29) did not initially exhibit ITC in the lights-on phase but developed ITC when imaged with the lights off. Persistent ITC was seen in 16.6% (24 eyes) in both lighting conditions. ITC occurred in 52.2% of the eyes with ACD less than 2.18 mm. Logistic regression showed that there is a 91% decrease in the odds of having ITC in lights-off condition for every millimeter of ACD increase. Age was not associated with the occurrence of ITC in the lights-off condition. All other analyzed parameters decreased significantly in the lights-off condition (p<0.05) except for the ACD, nasal TISA-500, and temporal SSA.@*Conclusions@#The presence of ITC is a well-established characteristic of eyes with angle closure. In eyes with PACS, detection of ITC may be enhanced with AS-OCT imaging in lights-off condition.
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Tomography, Optical CoherenceABSTRACT
@#AIM: To compare the differences of corneal diameter measured with wavelight anterior segment analyzer(Wavelight),IOL-master optical bio-measurement(LS900), anterior segment OCT(AS-OCT)and gauge.<p>METHODS: Totally 89 patients(177 eyes)with myopia who want to accept ICL were examined before operation with more than five kinds of instruments respectively, white to white(WTW)were examined with Wavelight, IOL-master, LS900 and gauge, angle to angle(ATA)with AS-OCT. Then the size of ICL was calculated based on the value of gauge. The vault of ICL was examined with OCT 3mo after operation.<p>RESULTS: WTW was(12.45±0.73, 11.96±0.39, 11.92±0.36, 11.49±0.30)mm measured by Wavelight, IOL-Master, LS900 and gauge respectively, ATA was(11.80±0.44)mm with AS-OCT. The value of gauge was the smallest one among them(all <i>P</i><0.01). Among four instruments, there was no statistical difference between LS900 and AS-OCT(<i>P</i>=0.098), they can instead of each other; there were differences among other instruments(<i>P</i><0.01). The size of ICL based on gauge was(12.77±0.37)mm. The vault of ICL is(537.41±181.22)μm 3mo after implantation obtained by OCT.<p>CONCLUSION: Gauge is ideal tool for measuring corneal diameter, it cannot be instead. Wavelight, IOL Master, LS900 and AS-OCT can be taken as reference.
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Purpose: To image trabeculectomy blebs using anterior segment optical coherence tomography (AS‑OCT), and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months. Materials and Methods: This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS‑OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper‑reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months. Results: At six months successful bleb function was noted in 44 (81.5%) eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11%) and multiform wall reflectivity in 48 eyes (89%). In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%), microcysts with subconjunctival separation in 12 eyes (22%) and only microcyst in 10 eyes (19%). When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001). Conclusion: AS‑OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.