Review of ocular ultrasonography

SELECTED OPHTHALMIC TESTS AND OCULAR DIMENSIONS IN RELATION TO ACTIVITY PATTERN IN THREE NEOTROPICAL NONHUMAN PRIMATES: BLACK-TUFTED MARMOSET (CALLITHRIX PENICILLATA), GUIANAN SQUIRREL MONKEY (SAIMIRI SCIUREUS), AND AZARA'S NIGHT MONKEY (AOTUS AZARAE INFULATUS)

The goals of this study were to compare ocular morphology, determine the reference intervals of selected ophthalmic tests, ocular measurements, intraocular pressure, and tear production, and to establish possible relationships in the visual ecology of three different Neotropical nonhuman primates (NHP). Nineteen black-tufted marmosets (Callithrix penicillate), 24 Guianan squirrel monkeys (Saimiri sciureus), and 24 night monkeys (Aotus azarae infulatus) were included in the study. Schirmer tear test, ocular dimensions, ocular ultrasonography, intraocular pressure, central corneal thickness, and corneal touch threshold were determined. The ratio of the average corneal diameters and axial diameters (CD/AGL) were established. No significant difference was noted between males and females, nor left and right eyes, for all three species for all measurements (P > 0.05). CD/AGL ratio was significantly higher (P < 0.0001) in night monkeys (a nocturnal species) as compared to black-tufted marmoset and Guianan squirrel monkeys (two diurnal species). The reference intervals will aid veterinary ophthalmologists to more accurately diagnose pathological changes in the eyes of these species. In addition, ocular dimension comparison will allow other NHP species to be evaluated and examined in relationship to behavioral traits (nocturnal versus diurnal).

Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs

OBJECTIVE

We aimed to track and evaluate the association between vitreous degeneration and the development of cataracts or retinal detachments in dogs over a long period.

ANIMAL STUDIED

Data on vitreous degeneration, cataracts, and retinal detachment in 102 eyes were collected from 68 dogs who underwent ocular ultrasonography at least twice between March 2017 and November 2021 at the Veterinary Medical Teaching Hospital, Konkuk University. The mean follow-up time was 515 ± 256 (mean ± standard deviation; range: 81-1196) days.

PROCEDURE

Development of cataracts and retinal detachment, according to the severity of vitreous degeneration grade (VDG), was evaluated during long-term follow-up.

RESULTS

In the cataract study (87 eyes, 61 dogs), the number of cataracts developed according to VDG (grade: 0-3) were as follows: VDG 0: 1 in 10 (10%) eyes, VDG 1: 15 in 35 (43%) eyes, VDG 2: 15 in 30 (50%) eyes, and VDG 3: 10 in 12 (83%) eyes. It was significantly different among grades (p = .026). In the retinal detachment study (95 eyes, 64 dogs), the number of retinal detachments developed according to each VDG were as follows: VDG 0: 0 in 11 (0%) eyes, VDG 1: 1 in 36 (3%) eyes, VDG 2: 5 in 35 (14%) eyes, and VDG 3: 4 in 13 (30%) eyes. It was also significantly different among grades (p = .019).

CONCLUSIONS

During long-term follow-up, dogs with severe vitreous degeneration had an increased risk of cataract and retinal detachment development than those without or with mild vitreous degeneration.

Imaging of Uveal Melanoma—Current Standard and Methods in Development

Simple Summary

Uveal melanoma is the most prevalent intraocular tumor in adults, derived from melanocytes; the liver is the most common site of its metastases. Due to troublesome tumor localization, different imaging techniques are utilized in diagnostics, i.e., fundus imaging (FI), ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), or fundus autofluorescence (FAF). Specialists eagerly use these techniques, but sometimes the precision and quality of the obtained images are imperfect, raising diagnostic doubts and prompting the search for new ones. In addition to analyzing the currently utilized methods, this review also introduces experimental techniques that may be adapted to clinical practice in the future. Moreover, we raise the topic and present a perspective for personalized medicine in uveal melanoma treatment.

Abstract

Uveal melanoma is the most common primary intraocular malignancy in adults, characterized by an insidious onset and poor prognosis strongly associated with tumor size and the presence of distant metastases, most commonly in the liver. Contrary to most tumor identification, a biopsy followed by a pathological exam is used only in certain cases. Therefore, an early and noninvasive diagnosis is essential to enhance patients’ chances for early treatment. We reviewed imaging modalities currently used in the diagnostics of uveal melanoma, including fundus imaging, ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), fundus autofluorescence (FAF), as well as positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI). The principle of imaging techniques is briefly explained, along with their role in the diagnostic process and a summary of their advantages and limitations. Further, the experimental data and the advancements in imaging modalities are explained. We describe UM imaging innovations, show their current usage and development, and explain the possibilities of utilizing such modalities to diagnose uveal melanoma in the future.

Case Report: Ultrasonography and Magnetic Resonance Imaging of Anterior Segment Dysgenesis in a Calf

This study includes diagnostic efficacy of the antemortem, combined use of ultrasonography and magnetic resonance imaging (MRI) for the diagnosis of anterior segment dysgenesis. A 7-day-old male Holstein calf presented with progressive unilateral exophthalmos associated with enlargement of the right eyeball soon after birth. Ultrasonography of the enlarged right eyeball showed (1) a 2-cm-thick echogenic parenchymal lesion filling the anterior region of the right eyeball, (2) excess accumulation of the anechoic vitreous humor, and (3) absence of the lens structure. Antemortem examination using T2-weighted and fluid-attenuated inversion recovery MRI revealed a thickened, hyperintense anterior lesion and absence of the lens structure. These imaging findings were suggestive of anterior segment dysgenesis. Antemortem imaging showed no abnormalities other than the abnormal structure and size of the right eyeball; therefore, enucleation of the right eye was performed, which allowed intact healing without suppuration. Ocular ultrasonography enhanced the diagnostic accuracy due to the characteristic ultrasonographic findings of a thickened anterior lesion and absence of the lens structure in the eyeball, suggestive of anterior segment dysgenesis.

Tear Production, Intraocular Pressure, Ultrasound Biometric Features and Conjunctival Flora Identification in Clinically Normal Eyes of Two Italian Breeds of Chicken (Gallus gallus domesticus)

Simple Summary

In Italy, chickens are used for egg production and as courtyard/domestic animals and consequently veterinarians need to know their general and specialist characteristics. One key area is normal ocular measurements in order to understand any pathological changes affecting the eyes. For an accurate diagnosis and better management of ophthalmic diseases in chickens, this paper describes the normal values for the evaluation of ocular tear production, intraocular pressure, and biometric measurements of the eyes and on the microbial and cultural flora normally present in the conjunctival sac in two Italian chicken breeds.

Abstract

Given the abundance of chickens in Italy, it is important for veterinarians to know the normal state of chickens’ eyes in order to identify any ophthalmic pathological changes. The aim of this study was to determine the normal values of select ocular parameters and to evaluate conjunctival microflora in two Italian chicken breeds. Sixty-six healthy chickens underwent a complete ophthalmic examination, which included a phenol red thread test (PRTT) for the evaluation of tear production and the assessment of intraocular pressure by rebound tonometry. B-mode ultrasound biometric measurements and conjunctival microflora identification were also performed in twenty-seven chickens. Mean PRTT was 23.77 ± 2.99 mm/15 s in the Livorno breed and 19.95 ± 2.81 mm/15 s in the Siciliana breed. Mean intraocular pressure was 14.3 ± 1.17 mmHg in the Livorno breed and 14.06 ± 1.15 mmHg in the Siciliana breed. Reference ranges for morphometric parameters were reported in the two breeds. Twenty-three chickens (85.18%) were bacteriologically positive. Chlamydia spp. antigen was detected in 14.81% of chickens. No positive cultures were obtained for fungi. Normal reference range values for selected ophthalmic parameters were obtained in clinically healthy chickens, which could facilitate accurate diagnosis and better management of ophthalmic diseases in these animals.

Ocular Ultrasound Abnormalities and Optic Nerve Sheath Diameter in Dogs and Cats

Indications for, technique, and findings for normal and abnormal ocular ultrasound are discussed, with specific sonographic findings, images, differential diagnoses, and other considerations. Because the eye is a fluid-filled structure, ultrasound can be used as a screening test when pathology prevents direct examination. Structural abnormalities, such as lens luxation, retinal detachments, and intraocular and orbital masses, also may be defined better using point-of-care ultrasound. Details on additional ophthalmic diagnostics, treatment, and prognosis are not covered.

B-Scan Biometry and Color Doppler Ultrasound Imaging of the Eye in Clinically Normal Donkeys (Equus asinus): Effect of Laterality, Maturity and Gender

Despite the extensive research on ocular ultrasonography, there is paucity of information regarding ocular biometry and color Doppler imaging of the donkey's eye. This study establishes B-scan ocular biometry and color Doppler ultrasonographic reference values in normal donkeys and describes effect of laterality, maturity and gender on ocular biometry and vasculature. Forty (80 eyes) clinically normal immature and mature donkeys of both sexes were included. Transpalpebral ocular ultrasonography was made using a 12-MHz linear transducer. Biometric ocular measurements were made including the anterior chamber depth, central lens thickness, vitreous chamber depth, axial globe length, longitudinal globe length, lens pole diameter and posterior wall thickness. Color Doppler velocimetric measurements including peak systolic velocity and end-diastolic velocity were made. Blood flow indices represented by resistive and pulsatility indices were calculated. Results revealed that laterality and gender did not represent variability factors in ocular biometry (P >.05), while the animal's maturity had an influence on axial globe length (P <.001), longitudinal globe length (P = 0.000) and lens pole diameter (P = .000). Laterality had no effect on velocimetric parameters and indices (P >.05) while gender had significant effect on resistive index (P = .024), pulstality index (P = .000) and volume flow per area (P = .008). The state of maturity had significant effects on peak systolic velocity (P = .027) and blood volume flow per distance (P = .012), and area (P = .048). Ocular biometry and color Doppler ultrasonography provided a clinically useful tool to evaluate the donkey's eye that will be helpful in diagnosing donkeys with ocular diseases.

Ophthalmic examination, biometry, and histologic findings in captive inland bearded dragons (Pogona vitticeps)

OBJECTIVE

To report ophthalmic examination, biometry, phenol red thread test (PRTT), intraocular pressure (IOP), and histologic findings from a private collection of inland bearded dragons (Pogona vitticeps).

ANIMALS STUDIED

Fourteen inland bearded dragons.

PROCEDURES

Complete ophthalmic examinations were performed on all animals, including slit-lamp biomicroscopy, indirect ophthalmoscopy, fluorescein stain, phenol red thread test, and rebound tonometry. B-mode ultrasonography was used to measure anterior chamber depth, axial lens thickness, vitreal chamber depth, and axial globe length. Horizontal corneal diameter was estimated using ImageJ software. Histologic assessment was obtained for one of the bearded dragons that died following the study period.

RESULTS

The median PRTT value was 7.27 mm/15 seconds. Mean IOP was 6.29 ± 1.60 mm Hg and 2.14 ± 1.37 mm Hg using the dog and undefined calibration settings, respectively. Median axial globe length was 11.75 mm. Mean anterior chamber depth and mean lens thickness were 2.06 ± 0.35 mm and 3.38 ± 0.45 mm, respectively. Median vitreal chamber depth was 6.79 mm. Mean horizontal corneal diameter was 5.138 ± 0.346 mm. Two distinct ocular phenotypes were observed, with two of the bearded dragons having corneal globosa, deep anterior chambers, and tufts of iridal vessels and fibrillar material extending into the anterior chamber.

CONCLUSIONS

The ultrasound biometry, PRTT, and rebound tonometry results may serve as a guideline for ophthalmic parameters in healthy bearded dragons. Examination and testing of greater numbers of animals are necessary to establish true reference ranges and determine if the observed ocular phenotypes represent normal variants or pathologic changes.

Sensitivity, Specificity, and Accuracy of Color Doppler Ultrasonography for Diagnosis of Retinal Detachment

Purpose

This study evaluated the sensitivity, specificity, and diagnostic accuracy of Color Doppler Ultrasonography (CDUS) in patients with suspected retinal detachment (RD) who underwent surgery.

Methods

In this prospective, observational clinical study, 65 eyes of 65 consecutive patients with suspected RD with opaque media were included. Following a standardized protocol, CDUS of the retina of the affected eye was performed. The sensitivity, specificity, and diagnostic accuracy of CDUS were determined and compared to the findings during surgery.

Results

The mean age of patients (18 men and 47 women) was 52.36 years (range: 8–77 years). The sensitivity, specificity, and overall accuracy of ocular CDUS were 91.3%, 88.1%, and 89.2%, respectively. The false-negative rate (negative CDUS images but presence of RD at operation) was 3.1% (2/65) and the false-positive rate (positive CDUS images but absence of RD at operation) was 7.7% (5/65).

Conclusion

CDUS of the retina could be considered as a promising tool in the diagnosis of RD in patients with opaque media.

Applicability of optical coherence tomography in blue-fronted parrots (Amazona aestiva)

OBJECTIVE

Optical coherence tomography (OCT) measurement of adult blue-fronted parrots (Amazona aestiva), free from infectious, inflammatory or neoplastic systemic diseases and from any ophthalmological illness, aim at its characterization, as well as to standardize the examination technique for the species.

PROCEDURE

Pupillary dilation was achieved with rocuronium bromide (5 mg/mL) at 0, 2, 15, 17, 30, and 32 minutes. The animals were sedated with midazolam maleate (0.5 mg/kg/IM) and anesthetized with propofol (5.0 mg/kg/IV). Measurements were made to evaluate the thickness of the total retina (TR), sensorineural retinal (SR), and ganglion cell complex (GCC), 2 millimeters (mm) from the pecten toward the fovea. OCT data were compared to measurements of retinal histological slides from enucleated eyes of blue-fronted parrots, scanned in automatic fluorescence microscope and measured with by the VS-ASW^® software.

RESULTS

Averages of measurements from the 43 retinas evaluated by OCT were TR: 279.40 micrometers (μm), SR: 255.90 μm, and GCC: 138.60 μm, respectively, and the measurements of six retinas using fluorescence microscopy were 260.30 μm for TR, 238.20 μm for SR, and 129.30 μm for GCC, demonstrating a high correlation coefficient between all measurements (r = .8698, P < .0001). It is also possible to evaluate the anatomy of the retina and to identify its layers, variations and abnormalities using OCT images. Variations were found between the different areas of the retina, both in the images of the histological slides and in the images of the OCT.

CONCLUSION

Optical coherence tomography is a valuable technique for in vivo evaluation of retinal structures in blue-front parrots, providing detailed and accurate images. This method improves the understanding of retinal diseases, monitoring the beginning, progression and therapy of retinal diseases, in the same individuals during longitudinal studies. In comparison to histological investigations, OCT enables imaging in vivo, therefore reducing the number of euthanized animals or enucleated eyes.

Ocular Ultrasonography and Biometry in the Cinereous Vulture (Aegypius monachus)

To establish reference standards for ocular ultrasound and biometry, 24 cinereous vultures (Aegypius monachus) (45 eyes) underwent B-mode and A-mode ultrasonographic examination using a 12.5-MHz probe. The vultures were manually restrained without sedation, and the eyes were topically anesthetized. Biometry was performed in the sagittal plane for axial length of the globe (AGL), anterior chamber depth (ACD), lens thickness (LT), and vitreous chamber depth (VCD). Biometry of the pecten oculi (LP) was measured on images of transversal scan at 9 hours. Biometric findings were as follows: AGL=27.74 ± 0.77 mm, ACD=3.73 ± 0.62 mm, LT=5.41 ± 0.18 mm, VCD=18.60 ± 0.58 mm, and LP=10.21 ± 1.19 mm. No correlation was found between body weight and AGL. Right and left globe sizes were not significantly different, but AGL and VCD were significantly longer (P < .05) in male than in female vultures. Including diagnostic protocols such as ocular ultrasound may improve the ophthalmologic care of endangered raptors injured by blunt trauma, when opacities of the ocular media prevent examination of the internal ocular structures.

Clinical Features and Computed Tomography Findings Are Utilized to Characterize Retrobulbar Disease in Dogs

The objective of this study is to describe the clinical features and computed tomography (CT) findings of dogs with retrobulbar disease. There are two facets to this study: a retrospective case series in which findings of dogs with primary vs. secondary retrobulbar disease are described, and a retrospective cross-sectional study in which computed tomography findings of dogs with retrobulbar neoplasia vs. infection/inflammation are described and compared. The medical records of 66 client-owned dogs diagnosed with retrobulbar disease between 2006 and 2016 were reviewed. Clinical information including signalment, the specialty service to which the dog was presented, clinical signs, physical examination findings, diagnostic results, treatment, and outcome were documented. Diagnostic imaging and histopathology were reviewed. Forty-one dogs (62.1%) were diagnosed with primary disease of the retrobulbar space; 25 dogs (37.9%) were considered to have secondary retrobulbar disease. Of the 41 dogs with primary retrobulbar disease, 19 were diagnosed with neoplasia, 19 with infectious/inflammatory disease, and 3 suffered traumatic insult to the retrobulbar space. Of the 25 dogs with secondary retrobulbar disease, 21 were diagnosed with neoplasia, 3 with infectious/inflammatory disease, and 1 with a cyst. Dogs had a combination of ocular, oral, and/or nasal clinical signs. CT findings of orbital osteolysis, orbital periosteal reaction, and presence of a retrobulbar mass were significantly associated with neoplasia, while zygomatic salivary gland enlargement, retrobulbar mass effect, and mandibular lymphadenopathy were more often associated with infectious/inflammatory disease. CT findings overlap among different retrobulbar diseases, but new bone formation and lysis are more often associated with neoplasia. Disease originating from the retrobulbar space was equally likely to be infectious/inflammatory (n = 19) or neoplastic (n = 19), based on definitive diagnostic results of dogs with primary retrobulbar disease. Due to the clinical ramifications of these disorders, the diagnosis and treatment of these cases should be managed with a multi-specialty approach.

Visualization and Quantitative 3D Analysis of Intraocular Melanoma and Its Vascularization in a Hamster Eye

A tumor vasculature network undergoes intense growth and rebuilding during tumor growth. Traditionally, vascular networks are histologically examined using parameters such as vessel density determined from two-dimensional slices of the tumor. Two-dimensional probing of a complicated three-dimensional (3D) structure only provides partial information. Therefore, we propose the use of microcomputed tomography (micro-CT) imaging to analyze the evolution of a tumor vasculature in an experimental ocular tumor model. A Bomirski Hamster Melanoma was implanted in the anterior chamber of a hamster eye. Ultrasound (US) imaging of the same tumor was performed in vivo, and the vascular results obtained using the two methods were compared. Normal ocular tissues, a tumor, and a tumor vascular structure were revealed with high accuracy using micro-CT. The vessels that grew within the tumor were chaotic, leaky, and contained many convoluted micro-vessels and embolizations. They comprised 20–38% of the tumor mass. The blood flow in the larger functional vessels was in the range from 10 to 25 mm/s, as determined by in vivo Doppler US. The micro-CT imaging of the hamster eyeball enabled both qualitative and quantitative 3D analyses of the globe at a histological level. Although the presented images were obtained ex vivo, micro-CT noninvasive imaging is being developed intensively, and high-resolution in vivo imaging is feasible.

Ocular biometry by computed tomography in different dog breeds

OBJECTIVE

To (i) correlate B-mode ocular ultrasound (US) and computed tomography (CT) (prospective pilot study), (ii) establish a reliable method to measure the normal canine eye using CT, (iii) establish a reference guide for some dog breeds, (iv) compare eye size between different breeds and breed groups, and (v) investigate the correlation between eye dimensions and body weight, gender, and skull type (retrospective study).

PROCEDURE

B-mode US and CT were performed on ten sheep cadaveric eyes. CT biometry involved 100 adult pure-bred dogs with nonocular and nonorbital disease, representing eleven breeds. Eye length, width, and height were each measured in two of three planes (horizontal, sagittal, and equatorial).

RESULTS

B-mode US and CT measurements of sheep cadaveric eyes correlated well (0.70-0.71). The shape of the canine eye was found to be akin to an oblate spheroid (a flattened sphere). A reference guide was established for eleven breeds. Eyes of large breed dogs were significantly larger than those of medium and small breed dogs (P < 0.01), and eyes of medium breed dogs were significantly larger than those of small breed dogs (P < 0.01). Eye size correlated with body weight (0.74-0.82) but not gender or skull type.

CONCLUSIONS

Computed tomography is a suitable method for biometry of the canine eye, and a reference guide was established for eleven breeds. Eye size correlated with breed size and body weight. Because correlation between B-mode US and CT was shown, the obtained values can be applied in the clinical setting, for example, for the diagnosis of microphthalmos and buphthalmos.

Congenital cataract associated with persistent hyperplastic primary vitreous and persistent tunica vasculosa lentis in a sambar deer (Rusa unicolor) - clinical, ultrasonographic, and histological findings

Ultrasonography suggested the diagnosis of cataract associated with persistent fetal intraocular vasculature in a 26-day-old sambar deer. The deer was ill and died despite intense critical care. Globes were removed. Histological characteristics of persistent fetal vasculature and secondary cataract are reported expanding the knowledge of ophthalmic disorders in wild ungulates.

Ultrasonographic biometry of the normal eye of the Persian cat

OBJECTIVE

To describe the normal ultrasonographic biometry of the Persian cat's eyes using B-mode ultrasonography.

METHODS

In a cross-sectional study, 20 healthy Persian cats with no history of previous ophthalmic disease were examined. Ocular biometry of the left and right eyes was measured using B-mode ultrasonography. Comparison of the average measurements between left and right eyes and between vertical and horizontal planes was performed using paired-sample t test. Correlation of ocular parameters with sex, age, head circumference and eye colour was evaluated.

RESULTS

Mean ± standard deviation (SD) measurements of the ocular structures of anterior chamber, lens thickness, vitreous chamber and anterior to posterior dimension of the globe in 40 eyes were 4.1 ± 0.7, 7.7 ± 0.5, 8.2 ± 0.4 and 20.7 ± 1.0 mm, respectively. No significant difference was found between the ocular biometry of the left and right eyes or the horizontal and vertical planes. Of the ocular parameters, the following had a significant positive correlation with head circumference: axial globe length, anterior chamber and lens thickness. The vitreous body had a positive correlation with age.

CONCLUSIONS

Regarding the breed predisposition of Persian cats to ocular problems, the present study provides baseline information for further clinical investigations of ocular abnormalities using B-mode ultrasonography.

Baseline assessment of ophthalmic parameters in the greater one-horned rhinoceros (Rhinoceros unicornis)

Five healthy captive greater one-horned rhinoceroses (Rhinoceros unicornis) were evaluated with standing sedation (detomidine hydrochloride 20-30 mg and butorphanol tartrate 50-60 mg per animal) to determine baseline values for tear production, intraocular pressure (IOP), conjunctival flora, and ocular anatomy using brightness mode transpalpebral ultrasonography with a 4- to 7-MHz broadband curvilinear transducer. The mean Schirmer tear test I value was 18.2 ± 3.49 mm/min. The mean IOP measured using applantation tonometry was 31.2 ± 6.62 mm Hg. Ocular biometry measurements were the following: axial length 2.61 ± 0.11 cm; corneal thickness 0.13 ± 0.01 cm; anterior segment depth 0.28 ± 0.06 cm; lens depth 0.70 ± 0.11 cm; and posterior segment depth 1.46 ± 0.13 cm. These values indicate that the globe is smaller than that of the domestic horse. All eight conjunctival swabs cultured bacterial and fungal microorganisms, with the most common being Staphylococcus spp. (57%). All bacterial isolates were considered to be commensal organisms due to the presence of mixed bacterial populations and lack of clinical signs of ocular disease. The data collected in this study should provide veterinarians with baseline information to assist in the diagnosis of ophthalmic conditions in the greater one-horned rhinoceros.

Ecobiometria ocular de cães glaucomatosos

Foram estudados olhos glaucomatosos de cães referidos no serviço de diagnóstico por imagem. Os pacientes foram submetidos à ultrassonografia em modo B de alta resolução para realização de biometria ocular, por meio da qual foram realizadas as seguintes medidas: espessura central da córnea, profundidade da câmara anterior, espessura da lente e profundidade da câmara vítrea. Para tal, foi realizada contenção física e instilado colírio anestésico. Foram aferidas a PIO e a paquimetria da córnea e, em seguida, foi realizada a ultrassonografia em modo B nos dois olhos. Além da diferença óbvia de PIO, maior nos bulbos glaucomatosos, os resultados mostraram-se estatisticamente significativos em dois parâmetros: aumento da profundidade da câmara vítrea nos casos de glaucoma crônico (1,24±0,26cm; P=0,01) quando se comparou aos olhos controle e aumento da espessura da córnea também nos casos de glaucoma agudo (0,987±0,28cm; P=0,027), quando se comparou aos olhos controle e aos olhos com glaucoma crônico. Observou-se que a câmara vítrea é a estrutura intraocular que mais contribui no processo de expansão de volume do bulbo (buftalmia) durante o glaucoma.

Avaliação ultrassonográfica do bulbo ocular em cães submetidos à facoemulsificação com ou sem implante de lente intraocular

Este trabalho objetivou descrever e comparar as alterações ultrassonográficas encontradas em bulbos oculares de cães submetidos à facoemulsificação, com ou sem implante de lente intraocular (LIO), no intuito de auxiliar no diagnóstico de alterações decorrentes da cirurgia e do implante da LIO, bem como sua correspondência com alterações clínicas. Dezenove cães portadores de catarata (21 olhos) foram submetidos ao procedimento de facoemulsificação e avaliados no pós-operatório tardio, aos cinco anos de evolução. Constituíram-se três grupos experimentais: afácicos (CA), formados por 11 cães; pseudofácicos (PP), com implante de duas LIOs em piggyback (n=5); e pseudofácicos (PL), com implante de uma LIO veterinária (n=5). Após exame oftálmico, todos foram submetidos ao exame ultrassonográfico, sob anestesia tópica, com transdutor linear multifrequencial de 10MHz; adicionalmente foram avaliadas medidas biométricas dos bulbos do olho. As principais alterações observadas foram: luxação da LIO, descolamento de retina, hialose asteroide e degeneração vítrea. O exame ultrassonográfico mostrou-se como excelente ferramenta diagnóstica e possibilitou a confirmação e a classificação dessas alterações. Na biometria ocular, pelas medidas entre o corpo ciliar e a câmara vítrea, o implante em piggyback resultou em redução destas em relação aos demais procedimentos instituídos, não havendo diferença ente o comprimento axial e a câmara anterior.

Intraocular pressure, ultrasonographic and echobiometric findings of juvenile Yacare caiman (Caiman yacare) eye

OBJECTIVE

The aim was to determine the intraocular pressure (IOP), the ultrasonographic and echobiometric findings in the eyes of juvenile Yacare caiman (Caiman yacare).

ANIMALS

Twenty-two healthy caimans from a breeding farm in Brazilian Pantanal.

PROCEDURES

Intraocular pressure was measured under physical restraint and topical anesthesia by applanation tonometry. Five individual measurements of each eye were recorded by the same examiner. B-mode ultrasonography was performed with a 10-MHz linear transducer, and the anterior chamber depth, lens thickness, vitreous depth, and axial globe length were measured. Unpaired and paired t-tests were used to assess data. Pearson's test was used to assess correlations between IOP and ocular structures (P < 0.05).

RESULTS

Mean ± SD IOP of the 44 eyes studied was 9.56 ± 2.69 mmHg, (range 5.4-15.6 mmHg). IOP did not differ significantly between right and left eyes or between genders (P > 0.05). Echobiometric measurements did not differ significantly between eyes and genders (P > 0.05). Intraocular structures measured in male and female subjects were, respectively, 2.61 ± 0.13 and 2.55 ± 0.18 mm for anterior chamber depth, 7.60 ± 0.17 and 7.54 ± 0.20 mm for lens thickness, 6.83 ± 0.20 and 6.90 ± 0.22 mm for vitreous chamber depth, and 17.55 ± 0.25 and 17.54 ± 0.29 mm for axial globe length. Correlations were not observed (P > 0.05).

CONCLUSION

Reference values of tonometry and distances of intraocular structures of Yacare caiman were described. IOP did not correlate with echobiometric measurements in this crocodilian. The ultrasonographic appearance was similar to other domestic and wild species.

Contribution of ocular B-mode and triplex Doppler in the evaluation of 10 Poodle dogs with cataracts

The findings of b-mode and especially triplex Doppler ocular ultrasound in the evaluation of 10 Poodle dogs with cataracts, which bring a contribution not yet reported in veterinary medicine, were reported. Ten Poodle dogs of varied ages and presenting cataracts were used. All animals were evaluated for ophthalmic and ultrasound examination. The ultrasound examination allowed the evaluation of the sonographic anatomy of the eye and measurement of the axial thickness of the lens (ATL). Using the Doppler mode, the blood flow of the ophthalmic artery and its vascular indexes, systolic velocity (SV), resistive index (RI) and pulsatility index (PI) were measured. Values found for ATL were 5.89±1.05 for the right eye (OD) and 6.07±1.32 for the left eye (OS). Values found using Doppler evaluation were SV OD: 26.54±7.05 and SV OS: 29.21±11.18; PI OD: 1.89±0.61 and PI OS: 1.7±0.35; RI OD: 0.76±0.1 and RI OS: 0.72±0.09 (OS). It was concluded that triplex Doppler was important for the determination of vascular indexes of the ophthalmic artery, which can be used for monitoring animals with hemodynamic alterations of the eyes and monitoring the therapy of ocular diseases.

A- and B-modes echobiometry in cataractous and noncataractous eyes of English Cocker Spaniel dogs

A- and B-modes ultrasonographic changes in the thickness of various structures of the eyeball in male and female English Cocker Spaniel dogs with and without nondiabetic cataracts were evaluated. Sixteen dogs with cataracts (32 eyes) and seven normal dogs (14 eyes) older than eight years were selected. A- and B-modes ultrasonography was performed with a 10MHz transducer. Data was statistically evaluated by one way ANOVA. Mean and standard deviations of various ocular structures for dogs with and without cataracts were, respectively, anterior chamber: 3.041±0.828mm, 3.373±1.040mm; lens: 6.817±1.117mm, 7.062±0.477mm; vitreous: 10.056±0.754mm, 9.523±0.705mm; and axial length: 19.909±1.103mm, 19.958±1.050mm. Ocular measurements between right and left eyes, males and females, as well as in eyes with and without cataract were not different (P>0.05).

Relação entre a biometria ultra-sonográfica em modo B do bulbo ocular e os diâmetros fronto occiptal e bizigomático em Canis familiaris

Avaliou-se 31 cães saudáveis, sem raça definida, sendo 10 machos e 21 fêmeas, com 8 meses a 7 anos de idade e peso de1,5-28 kg. Inicialmente foram mensurados os diâmetros fronto-occiptal (DFO) e bizigomático (DBZ) do crânio com o auxílio de um paquímetro. A ultra-sonografia transpalpebral em modo-B foi realizada para mensurar as estruturas do bulbo ocular, conforme se segue: D1- espessura da córnea; D2- distância entre o ponto central da imagem da córnea e a da cápsula anterior do cristalino (câmara anterior); D3- distância entre o ponto central da imagem da córnea e a da cápsula posterior do cristalino; D4- espessura do cristalino, que corresponde a distância entre a imagem da cápsula anterior e a cápsula posterior do cristalino; D5- diâmetro do cristalino, distância entre as imagens dos pólos do cristalino; D6- área do cristalino; D7- câmara vítrea, distância entre a imagem da cápsula posterior do cristalino e a retina; D8- distância entre a cápsula anterior do cristalino e a retina; D9- distância entre a imagem da córnea e a retina. Com exceção da D4, houve efeito dos DFO e DBZ sobre as medidas das estruturas internas do BO. A análise de regressão linear entre as medidas das estruturas do bulbo ocular e os DFO e DBZ foram significativas para D1, D2, D3, D4, D5, D6, D7, D8 e D9.

Ocular biometry in the adult anesthetized ferret (Mustela putorius furo)

A total of 44 eyes of 22 ferrets were examined by B-mode ultrasonography. Four dimensions were measured: the distance from the corneal surface to the anterior lens surface (M1), the axial lens thickness (M2), the distance from the posterior lens surface to the retina (M3) and the distance from the anterior cornea to the retina (M4). The values obtained were (mean, standard deviation, range): M1: 1.31 +/- 0.16 mm (1-1.7); M2: 3.42 +/- 0.15 mm (3.2-3.7); M3: 2.26 +/- 0.11 mm (2.1-2.5); M4: 7 +/- 0.24 mm (6.4-7.7). To our knowledge this is the first description of ocular biometric measurement in the ferret. These values show little variability of ocular dimensions in ferrets.

Standardised B-scan and A-scan echographic evaluation of spontaneous anterior uveal melanomas in the dog

In humans, A-scan echographic characteristics of choroidal and ciliary body malignant melanomas permit the prediction of histopathological findings in >95% of cases. The aim of this study was to determine the echographic characteristics, in A-mode and B-mode, of 16 spontaneous anterior uveal melanomas in the dog using a 10 MHz sector transducer. The acoustic hallmark of the tumours was their low to medium reflectivity, internal vascularity and hard consistency. All had an irregular shape, with no acoustic shadowing and the regular lesional spikes. In our experience, the most important sonographic differential diagnoses are ciliary body adenocarcinoma and chronic inflammatory lesions. We believe that standardised A-scan echography can be used in the evaluation and diagnosis of a very high percentage of anterior uveal melanomas.