Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography.

PURPOSE: To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT). METHODS: We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and ≥70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected. RESULTS: The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 ± 30 µm vs. 77 ± 16 µm; p < 0.001), as well as the superior and inferior quadrants (77 ± 16 µm vs. 86 ± 19 µm; p = 0.001). The mean episcleral thickness was larger in the superior (174 ± 54 µm) and inferior (141 ± 43 µm) quadrants, compared to the nasal (83 ± 38 µm) and temporal quadrants (90 ± 44 µm). The mean scleral thickness of the inferior quadrant was the largest (596 ± 64 µm), followed by the nasal (567 ± 76 µm), temporal (516 ± 67 µm) and superior (467 ± 52 µm) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 µm per age year (0.41-1.47 µm, p < 0.001). CONCLUSIONS: This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall.

Efficacy of transconjunctival approach for the treatment of orbital fractures: A protocol for systematic review and meta-analysis.

BACKGROUND: This study aims to assess the efficacy of transconjunctival approach (TCA) for the treatment of orbital fractures (OF) comprehensively and systematically. METHODS: In this study, we plan to search electronic databases of Cochrane Library, MEDLINE, EMBASE, Web of Science, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, China National Knowledge Infrastructure and for relevant randomized controlled trials. All these databases will be searched from inception to the March 1, 2020 without limitations of language and publication status. Two independent authors will carry out study selection, data collection, and study quality assessment. Any disagreements will be resolved by discussion with another author if necessary. The study quality will be assessed using Cochrane risk of bias tool. Statistical analysis will be conducted using RevMan 5.3 software. RESULTS: This study will be the first 1 to exert direct evidence to evaluate the efficacy of TCA for the treatment of OF. CONCLUSIONS: The findings of this study will provide an exhaustive view of TCA for the treatment of OF. STUDY REGISTRATION NUMBER: INPLASY202040154.

Long-term changes and effect of pterygium size on corneal topographic irregularity after recurrent pterygium surgery.

This retrospective observational study compared long-term topographic changes after recurrent- and primary-pterygium surgery depending on pterygium size. Patients who underwent recurrent-pterygium excision between 2002-2013 and age, sex, and pterygium size-matched controls who underwent primary-pterygium surgery were included (33 eyes of 33 patients in each group). Pterygium size was graded per advancing edge position: <1/3 of corneal diameter (grade 1), outside the pupil (grade 2), and within the pupillary area (grade 3). Surface asymmetry index (SAI), surface regularity index (SRI) in corneal topography, and uncorrected and best-spectacle-corrected visual acuity were compared before and 1, 3, 6, and 12 months postoperatively. Three, 17, and 13 eyes had grades 1, 2, and 3, respectively. In grade 2, the SAI and SRI were respectively significantly larger at all observation points (p = 0.01, 0.03, 0.02, 0.02, and 0.004) and before and 6 and 12 months postoperatively (p = 0.02, 0.04, and 0.03) in recurrent pterygium. In grade 3, the SAI was significantly larger before and 1, 3, and 12 months postoperatively (p = 0.04, 0.01, 0.01, and 0.02) and the SRI was significantly larger before and 12 months postoperatively (p < 0.001, 0.02) in recurrent pterygium. Corneal irregularity persisted 12 months after recurrent-pterygium surgery compared with that in same-size primary pterygium.

Retalho zigomático-palpebral: uma técnica opcional para a reconstrução da pálpebra inferior / Zygomatic-palpebral flap: an optional technique for lower eyelid reconstruction

Introdução: A reconstrução de pálpebra inferior representa um desafio peculiar ao cirurgião plástico, uma vez que traduz uma região facial de importância estética e funcional. O objetivo é apresentar uma técnica opcional para a reconstrução de defeitos da pálpebra inferior com o retalho cutâneo zigomáticopalpebral. Esta técnica mostra uma alternativa nos casos de pele escleroatrófica de pessoas idosas, bem como para pessoas jovens, que não apresentam redundância da pele palpebral superior, impossibilitando por exemplo o uso de enxertos de pálpebra superior ou retalhos como o de Fricke ou Tripier. Métodos: Os autores mostram a indicação do retalho em casos de ectrópio cicatricial, reconstrução após ressecção de neoplasias, associação com outros retalhos como de Hughes ou para cobertura de enxertos cartilaginosos. É um retalho de transposição composto por pele e subcutâneo, randomizado. A técnica baseia-se no uso de retalho local, de características muito semelhantes à área do defeito, o que permite mimetização, segurança e exequibilidade. Resultados: Os resultados imediatos e tardios são satisfatórios e bem aceitos pelos pacientes e pela equipe cirúrgica em termos estéticos e funcionais, com oclusão palpebral adequada e lubrificação ocular preservada. Conclusão: O retalho zigomático-palpebral apresenta como vantagens a simplicidade de execução, sangramento mínimo, baixa morbidade de área doadora e feito sob anestesia local. O objetivo de reconstruir defeitos da pálpebra é restaurar a anatomia e função. Esta pode ser uma tarefa desafiadora, especialmente em defeitos maiores que podem estar presentes nos procedimentos oncológicos em jovens e em idosos com pele escleroatrófica e mínima frouxidão.

Introduction: Lower eyelid reconstruction represents a unique challenge to plastic surgeons, since it involves a facial region of aesthetic and functional importance. The objective is to present an optional technique for the reconstruction of lower eyelid defects using zygomatic-palpebral skin flap. This technique represents an alternative in cases of scleroatrophic skin in older patients, and for young people who do not have an upper eyelid skin redundancy, which prevents, for example, the use of upper eyelid grafts or flaps such as those of Fricke or Tripier. Methods: The authors describe the flap used in cases of cicatricial ectropion and reconstruction after resection of neoplasms and association with other flaps, such as those of Hughes, or for coverage of cartilage grafts. The flap consisted of a transposition flap made up of skin and underlying subcutaneous tissues, randomized . The technique was based on the use of a local flap with highly similar characteristics to the defect area, which allowed it to mimic functions, while being safe and feasible. Results: The immediate and late results in terms of aesthetics and function were satisfactory and well accepted by patients and the surgical team, with adequate eyelid occlusion and preserved ocular lubrication. Conclusion: The advantages of the zygomatic-palpebral flap are its ease of execution, minimal bleeding, low morbidity of the donor area, and the use of local anesthesia. The reconstruction of eyelid defects aims to restore anatomy and function. This can be a challenging task, especially in cases with larger defects that may be present after oncologic procedures both in young and old patients presenting with scleroatrophic skin and minimal tissue laxity.

In vivo assessment of the anterior scleral contour assisted by automatic profilometry and changes in conjunctival shape after miniscleral contact lens fitting.

PURPOSE: To compare the shape of the anterior sclera of candidates to scleral lens (ScCL) fitting with regular and irregular corneas and analyze the changes induced in the shape of the sclero-conjunctiva after ScCL wear. METHODS: Thirty-five eyes of 18 subjects (19 eyes with irregular corneas and 16 with regular corneas) were consecutively recruited. Three measures of sclero-conjunctival shape were taken with Eye Surface Profiler (ESP, Eaglet Eye, Houten, The Netherlands). Tangent angles and ocular sagittal heights (OC-SAG) were analyzed at different chords from 13 to 17mm in the nasal, temporal, superior and inferior regions. The 19 eyes with irregular cornea were selected to wear ScCL and the changes in their sclero-conjunctival surface parameters were compared before and after 3h of lens wear. RESULTS: Irregular corneas showed higher OC-SAG values than regular corneas in all the chords analyzed, with statistical significant differences in the temporal region. Regarding tangent angles, regular corneas showed lower values (flatter surface), with statistical significant differences at 8 and 8.50mm on the nasal and 8.50mm on the temporal region. Some changes were seen in sclero-conjuctival shape after short-term ScCL wear. There was an augment in OC-SAG after 3h of scleral lens wear and a reduction on tangent angles, namely on the nasal region at 7.5mm and 8.00mm chord lengths, which is coincidental with the landing zone of ScCL. CONCLUSIONS: ESP shows mild differences in scleral shape between eyes with regular and irregular corneas. ESP might be valuable in quantifying the mechanical impact of the ScCL on the anterior eye surface.

Anterior eye surface changes following miniscleral contact lens wear.

PURPOSE: To quantify the effect of short-term miniscleral contact lens wear on the anterior eye surface of healthy eyes, including cornea, corneo-scleral junction and sclero-conjuctival area. METHODS: Twelve healthy subjects (29.9 ±â€¯5.7 years) wore a highly gas-permeable miniscleral contact lens of 16.5 mm diameter during a 5-hour period. Corneo-scleral height profilometry was captured before, immediately following lens removal and 3 h after lens removal. Topography based corneo-scleral limbal radius estimates were derived from height measurements. In addition, elevation differences in corneal and scleral region were calculated with custom-written software. Sclero-conjuctival flattening within different sectors was analysed. RESULTS: Short-term miniscleral lens wear significantly modifies the anterior eye surface. Significant limbal radius increment (mean ±â€¯standard deviation) of 146 ±â€¯80 µm, (p = 0.004) and flattening of -122 ±â€¯90 µm in the sclero-conjuctival area, (p << 0.001) were observed immediately following lens removal. These changes did not recede to baseline levels 3 h after lens removal. The greatest anterior eye surface flattening was observed in the superior sector. No statistically significant corneal shape change was observed immediately following lens removal or during the recovery period. CONCLUSIONS: Short-term miniscleral contact lens wear in healthy eyes does not produce significant corneal shape changes measured with profilometry but alters sclero-conjuctival topography. In addition, sclero-conjuctival flattening was not uniformly distributed across the anterior eye.

Ocular Surface Disease of Rabbits.

Rabbits have become a popular house pet that is encountered with increasing frequency in small animal veterinary practice. The unique anatomy of the rabbit predisposes them to developing surface ocular problems including the development of dacryocystitis, as well as conjunctivitis and keratitis. This article endeavors to give an updated outline of the various conditions affecting the rabbit ocular surface, with emphasis on diagnosis and treatment.

Ocular Examination and Corneal Surface Disease in the Ferret.

This article provides a brief, clinically relevant review of corneal surface disease in the ferret. A description of the ophthalmic examination of the ferret is provided. Stepwise descriptions of the most common ophthalmic abnormalities are provided, along with common rule-outs.

Ocular Surface Disease in New World Camelids.

This article discusses the anatomy, physiology, and common disease affecting the ocular surface of New World camelids, llamas, and alpacas.

Non-invasive evaluation of human mucosal structures by multiphoton laser scanning tomography in vitro.

BACKGROUND: Mucous membranes may be affected by various diseases and the diagnostic accessibility is limited. Multiphoton laser tomography (MPT) is a useful tool for in vivo evaluation of superficial skin structures and might also be useful for the imaging of mucosa. OBJECTIVES: In order to investigate the suitability of MPT for the evaluation of mucous membranes, tissue samples of different donors and anatomical localizations have been imaged. METHODS: Human mucosa samples from the urinary bladder, palatine tonsil and ocular conjunctiva were investigated by MPT and subsequently compared with conventional histology. RESULTS: Horizontal images of the epithelium and the underlying connective tissue were obtained using the autofluorescence and second harmonics generation signals by MPT. The stratification of multilayered epithelium was consistently reproduced. Also inflammatory changes like lymphocytic infiltrates and widened intercellular spaces were imaged in some cases. CONCLUSION: Mucous tissue samples were obtained and MPT imaging was successfully performed. In the direct comparison with histology of the same tissue samples, the characteristic morphology of the epithelia was found. Further studies are necessary in order to compare images of healthy and diseased mucosal epithelium and the use of MPT for its evaluation in vivo.

Carcinoma epidermoide de la conjuntiva asociado al virus del papiloma humano / Epidermoid carcinoma of the conjunctiva associated with human papillomavirus

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The Lymphatic Anatomy of the Lower Eyelid and Conjunctiva and Correlation with Postoperative Chemosis and Edema.

BACKGROUND: There are minimal data in the literature regarding the lymphatic drainage of the conjunctiva and lower eyelid and the relationship with postoperative chemosis and edema. METHODS: Injection, microdissection, and histologic and radiologic studies were conducted on 12 hemifacial fresh cadaver specimens. Indocyanine green lymphography was conducted in five volunteers. RESULTS: Histology identified lymphatic vessels superficial and deep to the orbicularis oculi. Cadaveric dissection, injection, and radiographic studies identified interconnecting superficial and deep facial lymphatic systems and a conjunctival lymphatic network draining through the tarsal plate to the deep lymphatic system. The superficial lymphatic collectors traveled in subcutaneous fat within the lateral orbital and nasolabial fat compartments. The lateral deep lymphatic collectors traveled beneath orbicularis oculi, then through the superficial orbicularis retaining ligament, and into the sub-orbicularis oculi fat in the roof of the prezygomatic space. These vessels descended to preperiosteal fat at the level of zygomaticocutaneous ligaments to travel adjacent to the facial nerve into preauricular nodes. Indocyanine green lymphography identified correlating draining pathways laterally to the parotid nodes and medially to submandibular nodes. CONCLUSIONS: The authors have found that the lower eyelid and conjunctiva are drained by interconnecting superficial and deep lymphatic systems of the face. The superficial system is vulnerable to damage in incisions and dissection in the infraorbital area. The deep system is vulnerable to damage in dissection around the orbicularis retaining ligament and the zygomaticocutaneous ligaments. The authors suggest that concurrent damage to both the superficial and deep lymphatic systems, especially laterally, may be responsible for postoperative chemosis and edema.

Upper and lower conjunctival fornix depth in healthy white caucasian eyes: a method of objective assessment.

PurposeEvaluating anti-scarring therapies require objective assessment of scarring, and knowledge of normal fornix anatomy. Measurement of conjunctival scarring has focused on inferior fornix shortening, although the superior fornix is often overlooked. There are data on normal fornix depth (FD) in South Asians, but there are no studies investigating normal conjunctival FD in white Caucasians. We designed a fornix depth measurer (FDM) for objective measurement of upper and lower conjunctival FD. The purpose of this study was to evaluate intra- and inter-observer variability, and to establish a reference for normal conjunctival FD in an ethnically white Caucasian population.Patients and methodsProspective cross-sectional study evaluating conjunctival FD in 252 clinically normal white Caucasian participants aged 20-80. Paired observers evaluated inter- and intra-observer variability. Data was analyzed using Bland-Altman plots and analysis of variance.ResultsFor white Caucasian subjects, mean upper and lower conjunctival fornix depths were 15.6 mm (95% confidence interval (CI), 12.5-18.8) and 10.9 mm (95% CI, 8.0-13.7), respectively. Females have smaller FDs (upper FD 15.3 mm±1.6 females, 16.2 mm±1.4 males, P<0.001; lower FD 10.6 mm±1.3 females, 11.3 mm±1.4 males, P<0.001). There was a progressive decline in FD with age (upper fornix depth 16.3 mm±1.2 at age 20-29, and 15.0 mm±1.8 at age 80+ (P=0.04)). There was 94-100% intra-observer and inter-observer agreement for upper and lower fornix measurements.ConclusionsUsing a slightly different custom-designed FDM, central conjunctival fornix depth in white Caucasian eyes appears to be similar to data previously reported in South Asian eyes. Fornix depth measurements were repeatable and reproducible.

Effects of Pigment Location in Tinted Contact Lenses on the Ocular Surface.

PURPOSE: To evaluate the effects of the location of pigments in decorative tinted soft contact lenses on the ocular surface. METHODS: Thirty test subjects were enrolled in this study. All subjects wore the following types of contact lenses, classified according to the location of the pigment layer, in one eye in three different testing sessions: conventional clear lenses, tinted lenses with a pigment layer embedded in the lens matrix, and tinted lenses with an exposed pigment layer on the surface. Tear samples were collected, the ocular surface status was evaluated, and subjective symptoms were surveyed after lens wear for 8 hours. RESULTS: The tinted lenses with surface pigments resulted in a greater increase in epidermal growth factor and interleukin-8 levels compared with the clear lenses and tinted lenses with embedded pigments (p < 0.050). Ocular surface parameters and subjective symptom scores were significantly different among three lens types (p < 0.050), with the clear lenses showing superior results compared with the two tinted lenses (p < 0.050). The tinted lenses with exposed pigments resulted in a greater degree of conjunctival redness and ocular surface staining and poorer symptom scores compared with the tinted lens with embedded pigments (p < 0.050). CONCLUSIONS: Our results suggest that the presence of surface pigments in tinted contact lenses increases ocular inflammation and results in a poorer ocular surface status and greater discomfort compared with clear lenses and tinted lenses with an embedded pigment layer.

Carcinoma escamoso conjuntival gigante. Tratamiento con cirugía seguido de interferón alfa-2b / Giant conjunctival squamous cell carcinoma. Treatment with surgery following topical interferon alpha-2b

CASO CLÍNICO: Un paciente varón de 50 años presentó una masa gigante e invasiva en el limbo nasal de su ojo derecho. Se trató precozmente con escisión quirúrgica sin márgenes libres, seguido de interferón alfa-2b tópico. Tras 2 años de seguimiento, el paciente continúa libre de enfermedad. DISCUSIÓN: En casos de carcinoma escamoso invasivo gigante de conjuntiva, invertir el orden de tratamiento realizando primero la escisión quirúrgica precoz seguida de interferón alfa-2b tópico puede resultar útil para lograr la remisión completa del tumor

CASE REPORT: A 50-year-old man presented with a giant and invasive mass at the nasal limbus in his right eye. A surgical excision without safety margins was promptly performed, followed by interferon alpha-2b (IFNα2b) eye drops. After monitoring the patient for two years and after performing a number of biopsies, he remains free from any signs of disease. DISCUSSION: For cases of giant and invasive squamous cell carcinoma, to reverse the order of treatment, by first performing an early tumour excision, followed by the application of topical IFNα2b, may prove useful to achieve total remission of the tumour

Differences Between Single and Double Eyelid Anatomy in Asians Using Ultrasound Biomicroscopy.

PURPOSE: The aim of this study was to clarify the differences between single and double eyelid structures quantitatively using an ultrasound biomicroscopy. DESIGN: A single-center observational study. METHODS: Upper eyelids of Asian volunteers were evaluated with a 50-MHz ultrasound biomicroscopy. The skin-orbicularis oculi complex (SOOC), levator aponeurosis, Mueller muscle-conjunctival complex, and tarsus were imaged at the eyelid crease in the double eyelid group and 7 mm above the eyelid margin in the single eyelid group. The SOOC was also measured 2 mm above the eyelid margin and 5 mm above the eyelid crease. RESULTS: Forty-two upper eyelids of 42 subjects were studied. Mean SOOC thickness at the eyelid crease was 0.62 ± 0.12 mm in single eyelids and 0.57 ± 0.08 mm in double eyelids (P = 0.03). Mean SOOC thickness at 2 mm above the eyelid margin and 5 mm above the crease was not significantly different between single and double eyelids (P = 0.004 and P = 0.62, respectively). The levator aponeurosis, Mueller muscle-conjunctival complex, and tarsus measured 0.38 ± 0.12 mm, 0.86 ± 0.28 mm, and 10.84 ± 1.10 mm in single eyelids and 0.39 ± 0.14 mm, 0.88 ± 0.34 mm, and 10.61 ± 1.36 mm in double eyelids (P = 0.75, P = 0.81, and P = 0.54, respectively). CONCLUSIONS: Single eyelids showed slightly thicker SOOC in the pre-tarsal area and at the eyelid crease but not 5 mm above the eyelid crease. The levator aponeurosis, Mueller muscle-conjunctival complex, and tarsus showed no differences in thickness.

Characterization of Upper Eyelid Tarsus and Lid Wiper Dimensions.

OBJECTIVES: To measure various dimensions of the upper tarsal plate and the area of upper lid wiper staining. The repeatability of the method of measurement was investigated. METHODS: Thirty-five healthy non-contact lens wearers were enrolled. The following parameters were measured from digital images of the upper eyelid captured with a slitlamp camera: length, height, and total area of the tarsal plate and area of lid wiper staining (lissamine green). Measurements were performed in a randomized and masked fashion on two separate occasions by the same investigator using ImageJ (National Institutes of Health). Coefficients of repeatability (COR) were calculated. RESULTS: The dimensions (mean±SD) of the tarsal plate were 20.6±1.9 mm length, 7.9±0.8 mm height, and 103.3±18.8 mm total area. The area of lid wiper staining was 2.7±2.0 mm. No association was found between tarsal dimensions and lid wiper staining (all P>0.05). Image analysis COR values were 0.6 mm tarsal length, 0.1 mm tarsal height, 1.2 mm tarsal area, and 0.4 mm lid wiper staining. There was no significant difference between repeated measurements for any parameter (all P>0.05). Limits of agreement were narrow for all parameters, indicating good agreement between repeated measurements. CONCLUSIONS: This work has demonstrated that there is a wide range in the dimensions of the upper tarsal plate in an urban UK population. No association was found between the upper tarsal dimensions and lid wiper staining. ImageJ was shown to be a repeatable method to measure the dimensions of the upper tarsal plate and upper lid wiper staining.

Tear ferning test in horses and its correlation with ocular surface evaluation.

OBJECTIVE: To describe the tear ferning test (TFT) in healthy horses and its correlation with other parameters for evaluating the ocular surface. ANIMALS STUDIED: Thirty male and female adult healthy horses (60 eyes), of no defined breed. PROCEDURES: Tear sample was collected with a microcapillary tube, placed on the surface of a glass slide, and allowed to dry at room temperature. The crystallization pattern was classified according to Rolando (Chibret International Journal Ophthamology, 1984; 2, 32). The program STEPanizer(©) stereology tool, version 1.0, was utilized for counting points on the digitally captured crystallization image. A conjunctival biopsy was performed. RESULTS: Tear ferning test was classified as Type I in 18 eyes (30%), Type II in 31 eyes (51.7%), and Type III in 11 eyes (18.3%), at a mean temperature of 27.3 ± 1.5 °C and relative humidity of 61.5 ± 5.7%. In the Type I crystallization, the count varied between 27 and 36 points (mean: 33.27 ± 2.40), in Type II between 22 and 31 points (25.42 ± 1.95), and in Type III between 13 and 25 points (16.82 ± 3.76). There was no statistical difference or correlation between the right and left eyes, nor was there a statistically significant influence (P < 0.05) on TFT by the factors evaluated. The mean goblet cells values were 50 ± 11.4 cells/field. All samples showed the presence of lymphocytes, plasmocytes, and eosinophils. CONCLUSION: Tear ferning test is easy to perform, without risks to the patient. Once standardized for horses, associated or not with the program STEPanizer(©) stereology tool, it is an additional method for evaluating the ocular surface.

In vivo evaluation of the cornea and conjunctiva of the normal laboratory beagle using time- and Fourier-domain optical coherence tomography and ultrasound pachymetry.

OBJECTIVE: To obtain normative data for the canine cornea and conjunctiva using high-resolution time- and Fourier-domain optical coherence tomography (TD-OCT and FD-OCT) and ultrasound pachymetry (USP). ANIMALS: One hundred sixty-eight eyes of 133 healthy young intact laboratory beagles. PROCEDURES: The cornea and conjunctiva of 16 eyes of 8 healthy young intact female beagles were imaged using FD-OCT. Corneal thickness was measured with FD-OCT and USP, while corneal epithelial thickness and conjunctival epithelial thickness were measured with FD-OCT. The central corneal thickness (CCT) was determined in 152 eyes of 125 healthy young adult intact female (35) and male (90) beagles using TD-OCT. Mixed effects linear regression was used for statistical analysis. RESULTS: The CCT was (mean ± standard deviation) 497.54 ± 29.76, 555.49 ± 17.19, and 594.81 ± 33.02 µm as measured by FD-OCT, USP, and TD-OCT, respectively. The central, superior paraxial, superior perilimbal corneal epithelial thickness and superior bulbar conjunctival epithelial thickness were 52.38 ± 7.27, 56.96 ± 6.47, 69.06 ± 8.84 and 42.98 ± 6.17 µm, respectively. When comparing techniques used for measuring CCT (USP vs. FD-OCT and FD-OCT vs. TD-OCT), USP and TD-OCT generated significantly greater values in comparison with FD-OCT (both P < 0.001). For all dogs, CCT increased with increasing age and body weight (both P < 0.001) and was higher in intact males vs. females using TD-OCT (P = 0.034). CONCLUSION: High-resolution FD-OCT and TD-OCT provide detailed noninvasive evaluation of in vivo canine anterior segment structures. Normative values of the canine cornea and conjunctiva are reported.