Temporal Limbus Research Articles

Does the palpebral morphology influence the tear meniscus height between Caucasian and Asian eyes?

The central lower TMH is used as a clinical measure of tear volume in the assessment of contact lens candidates and patients with dry eyes. Ethnic differences in eyelid morphology may influence the measurement of the TMH. Furthermore, with the advent of larger contact lenses, such as scleral lenses, it would be of clinical value to assess the TMH centrally and peripherally. The purpose of this study was to evaluate and compare the TMH at different positions along the palpebral margin between Caucasian and Asian eyes. This prospective study evaluated the lower TMH in five positions (central, temporal and nasal limbus and temporal and nasal periphery) of the right eye using the Keratograph 5M (Oculus) instrument in Caucasian and Asian participants between 10 am and 12 pm . The TMH at each position was taken three times and averaged and analyzed using a 5 × 2 repeated-measures analysis of variance. Central TMH did not differ significantly ( F = 0.02, p=0.88) in Caucasians (n = 20, aged 24.45 [2.30] years, TMH 0.320 [0.052] mm) and Asians (n = 20, aged 22.25 [3.43] years, TMH 0.325 [0.048] mm). A difference was noted with respect to TMH positions along the lid margin ( F = 64.17, p<0.001), independent of ethnicity ( F = 2.15, p=0.15). A post hoc analysis revealed a significantly higher TMH temporally when compared with centrally or nasally (p<0.001). This study demonstrated the similarity of the central TMH and the differences in the peripheral TMH within Caucasian and Asian eyes. This may be clinically relevant when using the Tear Film & Ocular Surface Society Dry Eye Workshop II diagnostic algorithm for dry eyes and when fitting scleral contact lenses. Future studies need to consider that ethnic differences may exist for certain tests in order to personalize the care and management of each patient.

A detailed survey of the murine limbus, its stem cell distribution, and its boundaries with the cornea and conjunctiva.

The narrow intersection between the cornea and conjunctiva, otherwise known as the limbus, is purported to harbor stem cells (SCs) that replenish the ocular surface epithelium throughout life. Damage to this site or depletion of its SCs can have dire consequences for eye health and vision. To date, various SC and keratin proteins have been used to identify the limbus, however, none could definitively mark its boundaries. Herein, we use the mouse as a model system to investigate whether structural and phenotypic features can be used to define the limbus and its boundaries with adjacent tissues. We demonstrate that differentially aligned blood and lymphatic vessels, intraepithelial nerves, and basal epithelial cellular and nuclei dimensions can be used as structural landmarks of the limbus. Identification of these features enabled approximation of the limbal expanse, which varied across distinct ocular surface quadrants, with the superior nasal and inferior temporal limbus being the widest and narrowest, respectively. Moreover, label-retaining SCs were unevenly distributed across the ocular circumference, with increased numbers in the superior temporal and inferior temporal moieties. These findings will heighten our current understanding of the SC niche, be beneficial for accurately predicting SC distribution to improve their isolation and devising efficacious cell therapies, and importantly, aid the ongoing search for novel SC markers.

A Retrospective Analysis of Corneal Dermoid.

Corneal dermoid is a congenital benign tumor and ocular malformation, often diagnosed at birth or in early childhood. Its treatment and long-term prognosis remain under-researched, necessitating further investigation. This study aims to investigate the epidemiological and clinical characteristics of corneal dermoid, evaluate the efficacy of different surgical methods, and identify factors influencing treatment outcomes. A retrospective analysis was conducted on the clinical data of 58 patients treated for corneal dermoid at our hospital from 2017 to 2021. Patients' demographic information, tumor characteristics, surgical methods, and postoperative outcomes were collected and analyzed. Descriptive statistics, independent sample t-test, chi-square (χ 2) test, and Spearman correlation analysis were used to evaluate the distribution characteristics and intergroup differences of corneal dermoid. The average age of the patients was 6.3 years, with 55.2% being male and 44.8% female. The right eye was affected in 63.8% of cases, with the temporal limbus being the most common site (75.9%). Pathological examination revealed tumors covered by squamous epithelium, containing hair follicles, sebaceous glands, adipose tissue, and fibrous tissue; some cases also had cartilage and glandular tissue. Surgical methods included corneal dermoid excision (100%), lamellar keratoplasty (37.9%), amniotic membrane grafting (31.0%), and autologous limbal stem cell transplantation (8.6%). None of the 50 followed up patients experienced tumor recurrence. Postoperative vision improved in 58.0% of patients, with more females (61.9%) experiencing visual impairment compared to males (38.1%) (χ²=4.711, p=0.030). This study analyzed 58 corneal dermoid patients treated from 2017 to 2021, focusing on epidemiological and clinical characteristics, surgical efficacy, and treatment outcomes. It identified common pathological features and effective surgical methods, with no tumor recurrence in followed up patients. The study highlights the need for further research with larger sample sizes and longer follow-up periods.

Assessment of Schlemm’s canal with swept-source optical coherence tomography in Graves’ ophthalmopathy

PurposeTo evaluate the Schlemm’s canal (SC) parameters obtained by swept-source optical coherence tomography (OCT) different in Graves’ ophthalmopathy (GO) eyes compared to healthy eyes.MethodsThis cross-sectional observational study evaluated 64 eyes of 32 GO cases and 56 eyes of 28 healthy controls. The study was conducted between October 2020 and June 2021. SC images were obtained from the temporal limbus of individuals using swept-source OCT. SC length (SCL) and SC area (SCA) were measured. The relationship between SC parameters in the patient group and intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, Graves’ disease (GD) duration, and clinical activity score (CAS) was evaluated.ResultsIn the GO group, 64 eyes of 32 patients were evaluated, and in the age and gender-matched healthy control group, 56 eyes of 28 individuals were assessed. SC images from 4 eyes of 4 patients in the patient group and 1 eye of 1 patient in the control group were not clear, preventing SCL and SCA measurements for these eyes. SCL and SCA measurements were found to be lower, and IOP and Hertel values were higher in the GO group compared to the healthy controls. However, no significant correlation was observed between SCL and SCA with IOP, RNFL thickness, GD duration, GO duration, or CAS in the GO group. In the GO group, the mean value of SCA was found to be higher in eyes with glaucoma or OHT compared to those without.ConclusionThese findings indicate that SC in GO-affected eyes is shorter and has a smaller area than in healthy individuals. Additionally, higher IOP and Hertel values were observed in the GO group compared to healthy controls. This study suggests that assessing SC using anterior segment OCT could provide valuable insights into the regulation of IOP and the development of glaucoma in GO-affected eyes.

Correlation Between Anterior Chamber Angle Status and Limbal Stem Cell Deficiency in Primary Angle-Closure Glaucoma

PurposeTo investigate the correlation between the opening and closing states of anterior chamber angle (ACA) and the density of limbal epithelial basal cells (LEBCs) in subjects with primary angle-closure glaucoma (PACG). DesignCross-sectional observational study. MethodsA total of 54 eyes of 29 patients diagnosed with PACG were included in the study. 54 eyes from normal subjects were included as control. Automatic evaluation system for ultrasound biomicroscopy images of anterior chamber angle was used to assist ophthalmologists in identifying the opening or closing state of ACA, and the in vivo confocal microscopy (IVCM) was used to evaluate the density of LEBCs in different directions. Results1. The average density of LEBCs in the superior, inferior, nasal and temporal limbus of the eyes in the PACG group was lower than that in the control group, and this pattern did not align with the density distribution observed in the control group.2. In the early, moderate and advanced PACG, the density of LEBCs corresponding to the closed angle was lower than that in the control group (P<0.05). Compared with the density of LEBCs corresponding to the closed angle and the open angle, the closed angle of PACG in the early, moderate and advanced stages was less than that in the open angle (P<0.05 in the early and moderate stages; advanced stage P>0.05).3. The basal cell density was processed by dimensionless analysis. In the data calculated by averaging and minimizing, both closed angle dimensionless values were smaller than the open angle (P<0.05).4. Comparative analysis was conducted among the normal, open-angle, and closed-angle conditions in the superior, inferior, nasal, and temporal limbus. In the early stage of PACG, significant differences were observed in 4 limbal regions (P<0.05), while in the moderate PACG stage, this difference was noted in 3 limbal regions (P<0.05). In advanced PACG, 2 limbal regions exhibited significant differences (P<0.05). These findings suggest that during the early PACG stage, angle closure is the predominant influencing factor on LEBCs density, while in the advanced stage, the decrease in density is attributed to a combination of angle closure and the natural progression of the disease. ConclusionThere is a significant correlation between anterior chamber angle status and LEBCs. Advanced PACG and angle closure should be highly suspected of the occurrence of limbal stem cell deficiency (LSCD).

Complications from the use of cyanoacrylate glue in conjunctival grafting for pterygium surgery: a case report

Background: Pterygium is a wing-shaped fibrovascular tissue overgrowth of the conjunctiva that crosses over the nasal or temporal limbus, or both, and grows onto the corneal surface. We report a case of complications due to the use of cyanoacrylate glue in conjunctival grafting in pterygium surgery.&#x0D; Case presentation: A 70-year-old Iban woman presented with worsening foreign body sensation in the nasal aspect of the left eye 10 years after undergoing nasal pterygium excision. The foreign body sensation had worsened over the course of 1 year. Upon examination, a greyish foreign body in the nasal aspect of the left eye(acrylate-like material) was noted.&#x0D; Conclusion: In this case report, we highlight the complications of the usage of cyanoacrylate glue in pterygium surgery and the possible intraoperative complications in this case.

Conjunctival nevus superimposed on a Pterygium with a possible corneal involvement

The presented photograph shows a suspicious lesion of conjunctival nevus in a 42-year-old patient. The patient reported that the lesion has been present since childhood and she does not believe that it has increased in size. The lesion is located near the temporal limbus and is superimposed on an early pterygium.

Bilateral ocular surface squamous neoplasia in xeroderma pigmentosum patient - A case report

A rare case of a 13yr old male patient presented with photophobia in both eyes and gradually progressive painless mass with watering, itching, and redness in the right eye for 2 months. Best-corrected visual acuity in Right eye 20/200 and Left eye 20/120. On examination, Right eye has a 6 x 6 mm fleshy pink oval pedunculated mass lesion arising from the temporal limbus and a 2mm hyperpigmented lesion in the nasal limbus. Left eye has a gelatinous white flat diffuse lesion with the pigmentation of 3mm both in the nasal and temporal limbus. Both eyes' Anterior segment, ocular motility, and fundus are normal. The patient had multiple hyperpigmented spots (freckles) and scaly skin on the face and trunk suggestive of Xeroderma pigmentosum for which he was on irregular treatment. Right eye tumor mass was excised with intraoperative control of surgical margins with adjunctive cryotherapy and sent for histopathology examination, which was confirmed as squamous neoplasia. Postoperatively, Both eyes started on Topical Mitomycin-c 0.02% 4 cycles, and the patient was carefully followed for any recurrence.

Unilateral Blepharoconjunctivitis due to Monkeypox Virus Infection

A 35-year-old Italian man presented with unilateral ocular pain and photophobia that started 7 days before presentation. Anterior segment examination (aided by asking the patient to pull down his lower eyelid; Fig A-B) revealed multiple (> 10) umbilicated papules on the tarsal and bulbar conjunctiva, the fornix, and at the temporal limbus; the fellow eye was uninvolved. He had multiple cutaneous, genital, oropharyngeal and anal vesicular-pustular lesions, generalized lymphadenopathy, and fever (Fig C-D).

Surgical treatment of limbal dermoid: Reports of cases

Ocular dermoid occur in an unusual and sporadic manner, being considered a congenital alteration, characterized by the presence of tissue of ectopic origin in ocular structures. They can develop in several places, including eyelids, conjunctiva, cornea and nictitating membrane. The objective was to report the cases of two dogs referred to the specialized service of veterinary ophthalmology, presenting tearing and ocular secretion secondary to the dermoid in the temporal limbus region, with extension to the cornea or conjunctiva. The dermoid were surgically treated by resection through conjunctivectomy combined with superficial lamellar keratectomy and corneal polishing with a diamond burr. Surgical excision of dermoid was curative.

Pterygium

Pterygium, also known as surfer’s eye, is a common ocular surface disorder originating in the limbal conjunctiva within the palpebral fissure with progressive involvement of the cornea. The fibrovascular lesion occurs more often at the nasal limbus than the temporal limbus, adopting a characteristic wing-like appearance. In this article we will discuss the presentation of pterygium, its underlying pathophysiology and the diagnostic steps taken by clinicians to recognise pterygium as well as the management of these patients.

SQUAMOUS CELL CARCINOMA OF THE CONJUCTIVA-CASE REPORT

&nbsp;Presentation of a patient with a squamous cell carcinoma of the conjunctiva on his left eye. A 83-year –old man with a squamous cell carcinoma of the conjunctiva was examined and treated at the University Eye Clinic in Skopje, by the ophthalmologist, after a ophthalmological examination and observation in the small country side-ophthalmology department for a year. Near the temporal limbus at 3 o’clock there was present nodous and white tumorous lesion around 1,4 cm. weath with elevation from the eye surface of 0,5 cm. Around the tumor there was local vascularization. &nbsp;External photographs were taken to document the lesion. The excision biopsy was performed. Topical antibiotic-steroid combination of eye drops was applied 3 times daily for 4 weeks after the primary excision of tumor. The diagnosis was pathohistologically confirmed at the Institute of Pathology in Skopje. Conclusion: Primary excision biopsy is preferably therapy and treatment. Also the primary excision biopsy is a golden standard for proper diagnosis for small squamous cell carcinoma of conjunctiva.Keywords: squamous cell carcinoma, conjunctiva, eye, pathohistology. Keywords: squamous cell carcinoma, conjunctiva, eye, pathohistology. &nbsp;

Correlation between Interpupillary Distance, Inner-Outer Canthal Distance and Inter Limbal Distance: A Cross-sectional Study

Introduction: Interpupillary Distance (IPD) is the distance between the centres of two pupils which can be anatomical or physiological. There are various inter orbital distances which are important in studying the orbitofacial configuration and also in prescribing a correct spectacle. Among the various measurements IPD is the most important which is routinely measured using AutoRefarctometer (AR) machine or Pupil distance meter. Aim: To find the correlation between IPD and Inner Canthal-Outer Canthal Distance (ICOC) and Right Nasal Limbus to Left Temporal Limbus (RNL-LTL) distance and to derive a regression equation in calculating IPD from measurements like ICOC and RNL-LTL which are easier to measure. Materials and Methods: In this cross-sectional study with a sample of 100 subjects, participants were randomly selected from individuals attending Outpatient Department at Vydehi Institute of Medical Sciences and Research Centre, Bengaluru, Karnataka, India, between March 2021 to August 2021. IPD was measured using Auto-Refarctometer/ Autorefractor Keratometer (AR/ARK) (Model: UNIQUE-RK:UNICOS URK 800F) and Pupillary Distance Metre (PDM) (Essilor). All the other measurements like Inner Inter Canthal Distance (IICD), Outer Inter Canthal Distance (OICD), RNL-LTL distance were measured using a transparent plastic ruler. Data was entered in Microsoft Excel and analysed using Statistical Package for the Social Sciences (SPSS) version 19.0. Categorical variables were presented as frequency and percentage. Multiple Linear regression was performed to find the factors associated with IPD using AR. The p-value &lt;0.05 was considered as statistically significant. Independent sample t-test was performed to compare mean values between males and females. Results: Of 100 subjects, 60 were males and 40 were females, 5 subjects were &lt;20 years and 95 subjects were ≥20 years. The analysis of the various distances found positive correlation between IPD measured using AR and PD meter with the other distances ICOC and RNL-LTL measured with transparent ruler, the strongest correlation found between RNL-LTL and IPD. The results were found to be statistically significant (p-value &lt;0.001 for all these comparisons). A regression equation was derived to calculate IPD using ICOC and RNL-LTL distances and also using other inter orbital variables. Conclusion: Since there was a positive correlation between IPD and ICOC and RNL-LTL distances, these measurements which are easy to perform can be used to calculate IPD in situations where it’s difficult to get access to AR machine as in peripheral community based camps or rural settings and in children and uncooperative patients where it is difficult to use AR machine to measure IPD.

Comparison of iridocorneal angle parameters measured by spectral domain optical coherence tomography and ultrasound biomicroscopy in dogs.

To compare the measurements of iridocorneal angle parameters between spectral domain optical coherence tomography (SD-OCT) and ultrasound biomicroscopy (UBM) in dogs. A total of 47 eyes of dogs were scanned at the temporal limbus using SD-OCT and UBM. Iridocorneal angle (ICA) and angle opening distance (AOD) were measured from the obtained images accordingly. The intra-observer and inter-observer reproducibility were evaluated using the intraclass correlation coefficient. To evaluate intra-observer reproducibility, measurements of the first and second grading from the first examiner were compared. To evaluate inter-observer reproducibility, measurements between the two examiners were compared. Agreement between ICA and AOD for SD-OCT and UBM was evaluated using Bland-Altman plots. In the first grading, the mean ICA and AOD for SD-OCT were 31.4±6.4° and 641.4±270.8µm, respectively. The mean ICA and AOD for UBM were 32.0±4.8° and 700.4±238.8µm, respectively. For ICA and AOD measurements, intra-observer reproducibility was excellent for both devices, whereas inter-observer reproducibility was excellent for SD-OCT and good for UBM. The mean difference in ICA between SD-OCT and UBM was 0.6° with a limit of agreement (LoA) span of 18.9°. The mean difference in AOD between SD-OCT and UBM was 58.9µm with a LoA span of 804.4µm. Spectral domain optical coherence tomography is an effective non-contact imaging modality for the evaluation of canine iridocorneal angle parameters in a clinical setting. Reproducibility of measurements obtained is comparable or superior to UBM, but values obtained by SD-OCT and UBM for AOD are not interchangeable between devices.

Morphological changes in the trabecular meshwork and Schlemm\u2019s canal after treatment with topical intraocular pressure-lowering agents

Glaucoma treatment is usually initiated with topical medication that lowers the intraocular pressure (IOP) by reducing the aqueous production, enhancing the aqueous outflow, or both. However, the effect of topical IOP-lowering medications on the microstructures of the aqueous outflow pathway are relatively unknown. In this retrospective, observational study, 56 treatment-naïve patients with primary open-angle glaucoma were enrolled. Images of the nasal and temporal corneoscleral limbus were obtained using anterior segment optical coherence tomography (AS-OCT). The conjunctival vessels and iris anatomy were used as landmarks to select the same limbal area scan, and the trabecular meshwork (TM) width, TM thickness, and Schlemm’s canal (SC) area were measured before and after using the IOP-lowering agents for 3 months. Among the 56 patients enrolled, 33 patients used prostaglandin (PG) analogues, and 23 patients used dorzolamide/timolol fixed combination (DTFC). After 3 months of DTFC usage, the TM width, TM thickness, and SC area did not show significant changes in either the nasal or temporal sectors. Conversely, after prostaglandin analog usage, the TM thickness significantly increased, and the SC area significantly decreased (all P < 0.01). These findings warrant a deeper investigation into their relationship to aqueous outflow through the conventional and unconventional outflow pathways after treatment with PG analogues.

Screening Evaporative Dry Eyes Severity Using an Infrared Image.

Background Dry eye disease (DED) is a multifactorial and one of the most common problems treated in an ophthalmic outpatient clinic. Due to the variability in presentation, diagnosis of DED consists of a combination of subjective and objective clinical tests. The purpose of this study was to assess the effectiveness of a handheld smartphone-based infrared thermal (IRT) camera for screening symptomatic evaporative DED. Methods This observational sex-matched control study assessed IRT images of 184 right eyes (46 normal and 138 DED) of 184 participants. Evaporative DED was assessed using noninvasive tear breakup time, fluorescein staining, and the Chinese version of the ocular surface disease index (C-OSDI) questionnaire and categorized into their respective dry eye symptomology group (none, mild, moderate, or severe). The ocular surface temperature (OST) at 8 anatomical regions of interest (ROI) (nasal conjunctiva, nasal limbus, nasal cornea, central cornea, inferior cornea, temporal limbus, temporal cornea, and temporal conjunctiva) were measured and compared using a handheld smartphone-based IRT camera. The effectiveness of these 8 ROIs OST in detecting varying severity of DED was evaluated in terms of correlations with severity of DED and their area under the curve (AUC). Results OST at the 8 anatomical ROI was significantly higher in DED participants than in the non-DED group (p < 0.05) except for inferior cornea, temporal limbus, and temporal conjunctival regions (>0.05). Analyzing 8 anatomical ROIs revealed that the nasal limbus had the highest Pearson correlation with the severity of DED (0.64, p < 0.001). Additionally, the nasal limbus ROI achieved the highest AUC of 0.79 (CI: 0.73–0.85; p < 0.05), sensitivity, and specificity (0.96 and 0.91) when comparing its ability to discriminated DED vs. non-DED eyes. Conclusions Rather than a diagnostic tool, handheld smartphone-based IRT images can be considered as a rapid, noninvasive, and hygienic screening tool in discriminating DED and non-DED and potentially alleviating inconvenience experienced during conventional tests.

Effects of Trabecular Meshwork Width and Schlemm's Canal Area on Intraocular Pressure Reduction in Glaucoma Patients.

PurposeTo evaluate the effects of baseline trabecular meshwork (TM) and Schlemm’s canal (SC) microstructures on intraocular pressure (IOP) reduction amount in treatment-naïve patients with primary open-angle glaucoma (POAG).MethodsA total 69 eyes of POAG patients who had not been treated with IOP-lowering agent were enrolled in this retrospective study. The patients had been prescribed topical IOP-lowering agent and used it for 1 year. The morphologic features of the TM and SC were collected using anterior segment module of spectral-domain optical coherence tomography with enhanced depth imaging at baseline. Images of the nasal and temporal corneoscleral limbus were obtained with serial horizontal enhanced depth imaging B-scans and TM width and SC area were measured in each scan. We investigated the effects of baseline TM and SC microstructures on IOP reduction amount.ResultsThe baseline IOP of 69 glaucomatous eyes was 17.9 ± 3.8 mmHg, and the mean amount of IOP reduction was 3.5 ± 2.1 mmHg after 1 year. Mean TM widths of nasal and temporal sector were 470.33 ± 80.05 and 479.74 ± 79.59 μm, respectively. SC area was measured as 4,818.50 ± 1,464.28, 4,604.23 ± 1,567.73 μm2 at nasal sector and temporal sector, respectively. The correlation analysis revealed a positive correlation between SC area and average amount of IOP reduction, indicating that the larger baseline SC area, the greater the IOP drop with topical IOP-lowering agents. However, no correlation was found between TM width and IOP lowering amount in patients with POAG.ConclusionsThe baseline SC area showed positive correlation with the IOP reduction amount in patients with POAG. This finding suggests that the SC area can be a clinical parameter to predict the IOP reduction amount before using IOP-lowering agents in POAG patient.

Clinical and Pathologic Presentation of Primary Ocular Surface Tumors among Zambians

Aim: This study aimed to characterize the clinical and pathologic presentation of ocular surface tumors (OSTs) and to more precisely differentiate the grades of ocular surface squamous neoplasia (OSSN) and benign lesions among Zambians. Methods: Two-hundred sixty-five Zambian patients presenting with ocular surface growths, suspicious for OSSN, were recruited between November 2017 and November 2019 to a cross-sectional study to investigate their lesions. Sociodemographic data were collected, HIV infection status and vision tests were performed, and lesions were measured and documented. Lesions >2 mm in diameter were excised and sent for pathology analysis. In addition to the biopsies, tears, blood, and buccal swabs were collected. CD4+ T-cell counts were measured by flow cytometry. Lesions were classified according to the WHO guidelines. χ² and bivariate correlations were used to analyze variable associations and strengths with phi/Cramer’s V and correlation coefficients, respectively. Binary logistics was used to adjust for covariance. Results: In this study, 68.3% of the participants were found to be HIV positive. The most frequent diagnoses were invasive OSSN (45.3%), preinvasive OSSN (29.1%), and pterygium (22.6%). Invasive OSSN comprised keratinizing squamous cell carcinoma (SCC) (87.5%), basaloid SCC (3.3%), and spindle cell carcinoma (3.3%). Unusual carcinomas, not described previously, included hybrid SCC (5.0%) and acantholytic SCC (0.8%). Invasive OSSN had advanced tumor (T3/T4) staging (93.3%) at diagnosis. Lymphadenopathy was rare (2.3%), and metastasis was absent. Patients were mostly female (59.2%). Median age was 36 (interquartile ranges 33–41) years (ranges 18–81). Patients with invasive OSSN were more likely to present with pain (p = 0.007), redness (p = 0.034), excessive tearing (p = 0.0001), discharge (p = 0.011), bleeding (p = 0.007), reduced vision (p = 0.0001), fungating lesion (p = 0.001), and blindness (p = 0.005); location at temporal limbus (p = 0.0001), inferior limbus (p = 0.0001), or circumlimbal (p = 0.001); and extension to cornea (p = 0.006) and forniceal palpebral conjunctiva (p = 0.001). Invasive OSSN was associated with any smoking habit and alcohol consumption (p = 0.04 and 0.03, respectively). HIV positivity was strongly associated with OSSN (74.6% OSSN vs. 49.3% benign lesions; p = 0.0001; phi: 0.237 [p = 0.0001]). Conclusion: OSTs are very common in Zambia and are strongly associated with HIV coinfection. Patients with OSSN were more likely to be HIV positive than those with pterygia. Despite the commonality of OSTs in sub-Saharan Africa, these cancers have historically been poorly characterized.

In vivo confocal microscopic characteristics of limbal stem cell deficiency

Objective: To investigate the cellular changes and quantitative analysis of basal cell density (BCD) and corneal epithelial thickness (CET) in limbal stem cell deficiency (LSCD) by in vivo confocal microscopy (IVCM). Methods: Prospective case-control study. A total of 35 eyes of 23 patients diagnosed with LSCD and 25 eyes from normal subjects were included in this study. Based on slit-lamp presentation and the global consensus on classification, the LSCD patients were classified into LSCD Ⅰ, LSCD Ⅱ and LSCD Ⅲ. Confocal images of the central cornea, and the superior, inferior, nasal and temporal limbus were inspected by IVCM. Morphologic characteristics of LSCD were summarized. The BCD and CET in all locations were measured. ANVOA or Kruskal-Wallis test was used for analysis when appropriate. A receiver operating characteristic was used to detect the diagnosis efficiency of BCD and CET. Results: The characteristics in the corneal epithelium of LSCD on IVCM included nested corneal epithelial cells, goblet cells with hyper-reflective spots, irregular basal cells and decreasing subbasal nerve density. The mean BCD of the LSCD group was (8 976±1 096) cells/mm2 in the central cornea. Compared to the control group, the BCD in the central cornea, superior, inferior, nasal and temporal limbus decreased by 30.2%, 26.0%, 28.7%, 29.3% and 30.2%, respectively (all P<0.007). The CET in the central cornea was (47.3±8.1) μm. The CET in the central cornea, superior, inferior, nasal and temporal limbus decreased by 27.9%, 23.7%, 20.6%, 26.9% and 23.1%, respectively, compared to the control group (all P<0.007). There was a decline of BCD and CET in more serious LSCD. Additionally, the decline of BCD and CET was shown in the unaffected region. The receiver operating characteristic showed the diagnosis efficiency of BCD in the corneal center and limbus (0.931 and 0.916) was superior to CET (0.853 and 0.817). Conclusions: There was a series of characteristic cellular changes in LSCD on IVCM. Both BCD and CET decreased significantly in LSCD. The BCD had higher diagnostic efficiency for LSCD.(Chin J Ophthalmol, 2020, 56:447-455).

Corneal Epithelial Thickness Measured Using Anterior Segment Optical Coherence Tomography as a Diagnostic Parameter for Limbal Stem Cell Deficiency

Using anterior segment optical coherence tomography (AS-OCT), we investigated the epithelial thickness (ET) of the central cornea and limbal regions in patients with limbal stem cell deficiency (LSCD) as a diagnostic and staging parameter. Prospective, cross-sectional study. The central corneal epithelium thickness (CET) and maximum limbal epithelium thickness (mLET) were measured in the superior, inferior, nasal, and temporal limbus on AS-OCT images of the normal and eyes with LSCD. CET was obtained by 1-point (OCT-CET1) and 3-point measurement (OCT-CET3). The values of OCT-CET1 and OCT-CET3 were compared to the CET obtained with invivo confocal microscopy (IVCM-CET). Sixty-eight eyes of 50 patients with LSCD and 52 eyes of 34 normal subjects were included. The mean (±standard deviation) OCT-CET3 was 55.0 ± 3.0μm (range, 50.6-62.0μm) in the control group and 41.6 ± 10.8μm (range, 0-56.3μm) in the LSCD group (P < .001). OCT-CET3 had a better correlation with IVCM-CET (r= 0.91) than did OCT-CET1 (r= 0.87, P= .001). The degree of reduction in OCT-CET3 increased in more advanced clinical stages of LSCD (all P < .001). The OCT-CET3 cutoff value that suggests LSCD was 46.6μm. Compared with the control group, the LSCD group had decreases in mLET in all 4 limbal regions (all P < .001). The sensitivity and specificity of OCT-CET3 is the highest among all mLET in detecting LSCD. Both CET and mLET were thinner in patients with LSCD than in normal subjects. OCT-CET3 appears to be a reliable parameter to confirm LSCD when there is clinical suspicion.