Length Of Globe Research Articles

Ophthalmic findings and reference values for selected ocular parameters in whooping cranes (Grus americana) and Mississippi sandhill cranes (Grus canadensis pulla).

To establish baseline ophthalmic parameters for an endangered, semi-wild population of healthy whooping cranes (Grus americana) (WHCR) and Mississippi sandhill cranes (Grus canadensis pulla) (SACR). Eighteen WHCR and 16 SACR. Ophthalmic examination was performed by a single observer, followed by conjunctival swab collection for aerobic bacterial culture and measurement of tear production (phenol red thread test, PRTT) and corneal diameter (CD) as tolerated. Measurement of the axial globe (AG) length, anterior chamber (AC) depth, lens thickness, vitreous chamber (VC) depth, and pecten length was performed via ocular ultrasound (OUS) as tolerated. Eyelid cicatrization (n = 1 WHCR), keratitis (n = 2 WHCR), incipient cataracts (n = 1 WHCR, n = 4 SACR), and uveal cysts (n = 1 SACR) were identified. Twenty-one bacterial species were cultured from SACR, while 18 bacterial species were cultured from WHCR. SACR under 6 months old had increased PRTT values compared to older SACR (p = .0432). AG length and VC depth of male WHCR were greater than in female WHCR (p = .0045 and p = .0008, respectively). WHCR less than 6 months old had greater AC depth and lens thickness than WHCR over 6 months (p < .001 and p = .0013, respectively). SACR less than 6 months old had greater AC depth and lens thickness than WHCR over 6 months (p < .0001 and p < .0001, respectively). WHCR and SACR are amenable to complete ophthalmic examination. Age-related differences in PRTT in SACR, sexual dimorphism in WHCR, and age-related differences in AC depth and lens thickness in WHCR and SACR were identified.

Comparative Study between Rocuronium And Magnesium Sulfate as Adjutants to Regional Anesthesia for Ophthalmic Surgeries using Peribulbar Block

Abstract Background Peribulbar anesthesia is frequently used in cataract surgeries. Compared to retrobulbar anesthesia, this approach is associated with less significant consequences. However, it has the disadvantages of a slower onset of orbital akinesia and the frequent requirement for block supplementation. Aim of the Work To evaluate the effect of addition of magnesium sulfate and rocuronium to standard local anesthetics mixture on the time of onset of globe and lid akinesia and corneal anesthesia for peribulbar block in ophthalmic surgeries. Patients and Methods This Prospective Double-blinded Randomized Study was carried out in the ophthalmic surgery unit, Ain Shams university hospital from January 2019 to April 2020. After institutional Ethical Board approval and obtaining written informed patients’ consents, 75 patients from both sexes, ASA physical status I-III, aged 40-80 years and having an Axial globe length less than or equals 26 mm scheduled for cataract surgery under peribulbar block were included in the study. Results Our study found statistically significant more rapid onset of action (mean time to start surgery) in rocuronium group (7.00±1.22) than control group and magnesium sulfate group (9.00±1.47 and 9.00±1.15) respectively, (p &amp;lt; 0.001); Moreover, no statistically significant difference was reported between control group and magnesium sulfate group. In addition, no significant difference was reported regarding duration of surgery between groups Conclusion Adding Rocuronium to local anesthetic mixture in peribulbar block during cataract surgery enhances ocular akinesia and corneal anesthesia and reduces the need for supplementary injections with no side effects and that was significantly better than Magnesium sulfate in term of rapid onset and time needed to achieve adequate condition to begin surgery. However, adding Magnesium sulfate showing good results regarding akinesia, corneal anesthesia and need for supplementary injections but it did not significantly fasten the onset of block and hence the time to start surgery.

Ocular biometry in rabbits using computed tomography.

To describe a repeatable method of measuring ocular structures and to establish ocular biometry reference ranges in adult domestic rabbits (Oryctolagus cuniculus) without medical history or imaging findings consistent with ophthalmic disease using a 64-slice multidetector computed tomography scanner. In this retrospective and observational anatomic study, 100 eyes from 50 rabbits without medical history or imaging findings consistent with ophthalmic disease who received a head computed tomography scan were selected for measurement of globe length, width, and height using 3D multiplanar reconstruction. Lens width and length, the anteroposterior length of the anterior and vitreous chambers, and attenuation of the lens and vitreous chamber were collected. These parameters were compared against age, sex, weight, body condition, and ear conformation. A reference guide was established, with globe width being the largest dimension (18.03 ± 0.81 mm), followed by height (17.18 ± 0.69 mm) and then length (16.64 ± 0.66 mm). Increased weight was associated with an increase in globe height (p = 2.43 × 10-5 ), length (p = 1.63 × 10-4 ), and width (p = 7.0 × 10-3 ). Increased age was associated with increased lens attenuation (p = 1.28 × 10-7 ) and increased transverse lens width (p = 1.64 × 10-3 ). Inter- and intra-observer agreement was excellent. CT is a reliable modality for measurement of ocular biometry dimensions in rabbits. These reference values can be applied to aid in identifying diseases that affect the dimensions of the ocular structures in rabbits over 18 months of age.

Ocular Ultrasonography and Effect of Topically Applied Rocuronium Bromide in Louisiana Pine Snakes (Pituophis ruthveni)

Abstract Louisiana pine snakes (Pituophis ruthveni) are a threatened species with a range limited to portions of Louisiana and Texas. There are captive reproduction programs that aim to assist in the recovery of this species. Therefore, obtaining information that can aid in maintaining their health, such as a complete ocular examination, is a critical component in conservation efforts. Examination of the snake ocular posterior segment is challenging due to the presence of striated uveal musculature which is unresponsive to anticholinergic agents, and the presence of the spectacle which may create a barrier to topical mydriatics. The objectives of this study were to document normal ocular biometric measurements (axial globe length (AP), lens thickness (LT) and vitreous chamber depth (VCD)) in this species using ultrasonography (US) and to assess the effects of topically applied rocuronium bromide (RB) solution (1- and 2-drop protocol, 20 μl and 40 μl, respectively) to facilitate non-invasive examination of the fundus. The ocular biometric measurements were then correlated to morphometric data including snout-vent length (SVL), tail length (TL), total body length (SVL + TL), sex and body condition score (BCS). We found that US, using an 8-18 MHz linear array probe, provided adequate image quality to measure the above parameters in all snakes (n = 8), and that there were no significant correlations between the morphometric data and ocular biometric US measurements (P &amp;gt; 0.05). RB solution applied topically to the healthy, intact spectacle did not induce mydriasis in a subset of this same population (n = 6) (P &amp;gt; 0.05) using either the 1- or 2-drop protocol. In conclusion, ocular US can be utilized as a non-invasive diagnostic tool in Louisiana pine snakes and further studies are needed to evaluate non-invasive methods of inducing mydriasis in this species.

Comparative study between rocuronium and magnesium sulfate as adjuvants to local anesthetics for peribulbar block

Background &amp; Objective: Peribulbar anesthesia is frequently used in cataract surgeries. Compared to retrobulbar anesthesia, this approach is associated with less significant consequences. However, the prolonged onset of orbital akinesia and the frequent need for block replenishment are considered drawbacks. We aimed to investigate the impact of adding rocuronium and magnesium sulfate to a commonly used local anesthetic combination on the onset of corneal anesthesia and the degree of lid and globe akinesia during peribulbar block in ocular surgeries.&#x0D; Patients and Methods: This prospective double-blinded randomized study was conducted in the ophthalmic surgery operating theater, Ain Shams University Hospital from January 2019 to April 2020. We enrolled 75 patients from both sexes, with American Society of Anesthesiology (ASA) physical status I–III, ages 40-80 y, and an axial globe length less than or equal to 26 mm planned for cataract surgery under peribulbar block in the study following institutional ethical board approval and written informed patient consents. Patients were randomly divided into three groups, 25 patients per group, based on the drugs they received: Group O (control group): received local anesthetic + 0.9% normal saline (1 ml). Group M: received local anesthetic + magnesium sulphate 50 mg in normal saline. Group R: received local anesthetic + rocuronium at a dose of 0.06 mg/kg (maximum 5 mg) in normal saline.&#x0D; Results: Our study found statistically significant more rapid onset of action (mean time to start surgery) in rocuronium group (7.00 ± 1.22 min) than control group and magnesium sulfate group (9.00 ± 1.47 and 9.00 ± 1.15 min) respectively, (P &lt; 0.001); Moreover, no significant difference was noted between control group and magnesium sulfate group. In addition, no relevant difference was reported regarding duration of surgery between the groups.&#x0D; Conclusion: During cataract surgery, the addition of rocuronium to the local anesthetic mixture in the peribulbar nerve block has been found to enhance ocular akinesia and corneal anesthesia. Furthermore, the use of rocuronium demonstrated a significantly faster onset and shorter time needed to achieve the appropriate conditions to initiate the surgical procedure compared to the use of magnesium sulfate. Addition of magnesium sulfate showed good results regarding akinesia, corneal anesthesia and need for supplementary injections but it did not significantly fasten the onset of block and hence the time to start surgery.&#x0D; Key words: Cataract; Magnesium Sulfate; Peribulbar Block; Rocuronium&#x0D; Citation: Nagy M, Abo El-Ella S, El-Shafey MA, Helal AM, Zekry MR. Comparative study between rocuronium and magnesium sulfate as adjuvants to local anesthetics for peribulbar block. Anaesth. pain intensive care 2024;28(1):55−61; DOI: 10.35975/apic.v28i1.2157&#x0D; Received: February 18, 2023; Reviewed: July 30, 2023; Accepted: December 23, 2023

Cat LCA-CRX Model, Homozygous for an Antimorphic Mutation Has a Unique Phenotype.

Mutations in the CRX transcription factor are associated with dominant retinopathies often with more severe macular changes. The CRX-mutant cat (Rdy-A182d2) is the only animal model with the equivalent of the critical retinal region for high-acuity vision, the macula. Heterozygous cats (CRXRdy/+) have a severe phenotype modeling Leber congenital amaurosis. This study reports the distinct ocular phenotype of homozygous cats (CRXRdy/Rdy). Gene expression changes were assessed at both mRNA and protein levels. Changes in globe morphology and retinal structure were analyzed. CRXRdy/Rdy cats had high levels of mutant CRX mRNA and protein. The expression of photoreceptor target genes was severely impaired although there were variable effects on the expression of other transcription factors. The photoreceptor cells remained immature and failed to elaborate outer segments consistent with the lack of retinal function. The retinal layers displayed a progressive remodeling with cell loss but maintained overall retinal thickness due to gliosis. Rapid photoreceptor loss largely occurred in the macula-equivalent retinal region. The homozygous cats developed markedly increased ocular globe length. The phenotype of CRXRdy/Rdy cats was more severe compared to CRXRdy/+ cats by several metrics. The CRX-mutant cat is the only model for CRX-retinopathies with a macula-equivalent region. A prominent feature of the CRXRdy/Rdy cat phenotype not detectable in homozygous mouse models was the rapid degeneration of the macula-equivalent retinal region highlighting the value of this large animal model and its future importance in the testing of translational therapies aiming to restore vision.

Clinical ophthalmic parameters of the Quaker parrot (Myiopsitta monachus).

Ophthalmic diagnosis in many avian species remains hindered by a lack of normative values. This study aimed to establish normal ophthalmic parameters for select diagnostic tests in clinically normal Quaker parrots. Ninety-six captive Quaker parrots aged 8-18 years underwent ophthalmic examination to include assessment of neuro-ophthalmic reflexes, phenol red thread test, rebound tonometry, fluorescein staining, palpebral fissure length measurements, slit lamp biomicroscopy, indirect ophthalmoscopy, and ocular ultrasound biometry. Menace response, dazzle reflex, and direct pupillary light reflex were present for all Quaker parrots. Tear production (mean ± SD) was 13.3 ± 4.0 mm/15 s and intraocular pressure (IOP, mean ± SD) was 10.6 ± 1.4 and 6.0 ± 1.3 mmHg in the D and P rebound tonometer calibration settings, respectively. For IOP measurement, D and P calibration settings were not interchangeable, with the lesser variation of the D setting preferred in the absence of a gold standard. Ultrasound measurement of the anterior chamber depth increased with age and males had longer axial globe and vitreous lengths. Incidental adnexal and ocular lesions, identified in 36/96 (37.5%) of Quaker parrots, did not statistically affect the created reference data. This work provides reference values and clinical findings to assist with monitoring the health of wild populations and maintaining the health of captive Quaker parrots.

The Effect of Orthokeratology Lens on the Axial Length of Globe in Children with Myopia in Asia

The aim of this meta-analysis was to determine the effect of orthokeratology (OK) lens on the axial length of the eye globe of Asian children with myopia of low and moderate degree compared with children treated with glasses. PubMed, Embase, Web of Science, and Cochrane Library were searched to collect relative researches on the treatment of OK lens in myopia children from January 2000 to July 2021. The authors adopted the standardised mean difference (SMD) as effect size, to estimate the pooled changes of axial length in Asian myopic children. Seven articles were identified. In Asian children with myopia of low to a moderate degree, compared with glasses treatment, axial length decreased significantly in the OK Lens group (SMD = -0.84, 95%CI: -1.10 ~ -0.58), with a p-value less than 0.05. According to the follow-up time, the subgroup analysis demonstrated that, SMD = -0.68 (95%CI: -1.43 ~ 0.08, p>0.05) for six months; SMD = -1.00 (95 %CI: -1.38~-0.62, p<0.05) for 12 months; SMD=-0.71 (95%CI: -1.20~-0.21, p<0.05) for two years. In conclusion, in the early treatment, compared with glasses, children with low and moderate myopia wearing OK lenses were more effective in reducing axial elongation in Asia. Key Words: Axial length, Orthokeratology, Myopia, Meta-analysis.

Normative globe position values on orbital computed tomography in Australians

ObjectifDéterminer par tomodensitométrie les valeurs correspondant à la position normale du globe oculaire, à la distance inter-zygomatique (DIZ) de même qu’à la longueur et à la largeur axiales du globe oculaire au sein d'une cohorte australienne. NatureÉtude de cohorte rétrospective. ParticipantsPatients qui ont fait l'objet d'une tomodensitométrie orbitaire, excluant ceux qui présentaient une atteinte bilatérale, qui avaient déjà subi une chirurgie orbitaire ou dont les images tomodensitométriques étaient de piètre qualité. MéthodesLa coupe axiale au milieu du globe a permis de mesurer la position du globe oculaire. La position antérieure du globe se définissait comme la distance perpendiculaire de la marge antérieure du globe à la ligne inter-zygomatique, tandis que la position postérieure du globe se définissait comme la distance perpendiculaire de la marge postérieure du globe à la ligne inter-zygomatique. RésultatsVoici les mesures normales (moyenne ± é.-t.) : DIZ, 97,4 ± 4,1 mm; position antérieure du globe, 18,8 ± 2,8 mm; position postérieure du globe, 6,2 ± 2,9 mm; longueur axiale du globe, 24,9 ± 1,1 mm et largeur axiale du globe, 25,9 ± 1,2 mm. On a pu établir une corrélation positive significative entre la DIZ et la position antérieure du globe (r = 0,15; p = 0,03), la longueur axiale du globe (r = 0,33; p < 0,01) et la largeur axiale du globe (r = 0,30; p < 0,01). ConclusionCes données normatives quant à la position du globe oculaire peuvent servir au diagnostic radiologique des exophtalmies ou des énophtalmies.

Measuring axial length of the eye from magnetic resonance brain imaging

BackgroundMetrics derived from the human eye are increasingly used as biomarkers and endpoints in studies of cardiovascular, cerebrovascular and neurological disease. In this context, it is important to account for potential confounding that can arise from differences in ocular dimensions between individuals, for example, differences in globe size.MethodsWe measured axial length, a geometric parameter describing eye size from T2-weighted brain MRI scans using three different image analysis software packages (Mango, ITK and Carestream) and compared results to biometry measurements from a specialized ophthalmic instrument (IOLMaster 500) as the reference standard.ResultsNinety-three healthy research participants of mean age 51.0 ± SD 5.4 years were analyzed. The level of agreement between the MRI-derived measurements and the reference standard was described by mean differences as follows, Mango − 0.8 mm; ITK − 0.5 mm; and Carestream − 0.1 mm (upper/lower 95% limits of agreement across the three tools ranged from 0.9 mm to − 2.6 mm). Inter-rater reproducibility was between − 0.03 mm and 0.45 mm (ICC 0.65 to 0.93). Intra-rater repeatability was between 0.0 mm and − 0.2 mm (ICC 0.90 to 0.95).ConclusionsWe demonstrate that axial measurements of the eye derived from brain MRI are within 3.5% of the reference standard globe length of 24.1 mm. However, the limits of agreement could be considered clinically significant. Axial length of the eye obtained from MRI is not a replacement for the precision of biometry, but in the absence of biometry it could provide sufficient accuracy to act as a proxy. We recommend measuring eye axial length from MRI in studies that do not have biometry but use retinal imaging to study neurodegenerative changes so as to control for differing eye size across individuals.

Keratometry, biometry, and prediction of intraocular lens power in adult tigers (Panthera tigris).

To calculate the necessary pseudophakic intraocular lens (IOL) power to approximate emmetropia in adult tigers. 17 clinically normal adult tigers. 33 eyes of 17 clinically normal adult tigers underwent routine ophthalmic examination and B-scan ultrasonography while anesthetized for unrelated procedures. Specific ultrasound data (globe measurements and corneal curvature) and estimated postoperative IOL positions were utilized to calculate predicted IOL power by use of Retzlaff and Binkhorst theoretical formulas. Applanation tonometry and refraction were also performed. Mean ± SD axial globe length was 29.36 ± 0.82 mm, preoperative anterior chamber depth was 7.00 ± 0.74 mm, and crystalline lens thickness was 8.72 ± 0.56 mm. Mean net refractive error (n = 33 eyes) was +0.27 ± 0.30 diopters (D). By use of the Retzlaff formula, mean predicted IOL power for the postoperative anterior chamber depth (PACD), PACD - 2 mm, and PACD + 2 mm was 43.72 ± 4.84 D, 37.62 ± 4.19 D, and 51.57 ± 5.72 D, respectively. By use of the Binkhorst equation, these values were 45.11 ± 4.91 D, 38.84 ± 4.25 D, and 53.18 ± 5.81 D, respectively. Mean intraocular pressure for all eyes was 14.7 ± 2.69 mm Hg. The calculated tiger IOL was lower than reported values for adult domestic felids. Further studies evaluating actual PACD and pseudophakic refraction would help determine the appropriate IOL power to achieve emmetropia in this species.

Corneal thickness and anterior chamber depth of the normal adult horse as measured by ultrasound biomicroscopy.

To determine corneal thickness (CT) and axial anterior chamber depth (ACD) using ultrasound biomicroscopy (UBM) in normal adult horses. To compare corneal thickness measurements between UBM and ultrasonic pachymetry. Sixty eyes of 30healthy adult horses aged 8-24years. Ultrasonic pachymetry (velocity of 1640m/s) was utilized to obtain measurements of the central, superior, temporal, inferior, and nasal cornea. Triplicate images of the same corneal locations were acquired using UBM (50MHz). Images of the axial anterior chamber were used to measure ACD. Intraocular pressure (IOP) was estimated using rebound tonometry, and axial globe length was measured using ultrasonographic biometry. CT (mean±SDµm) measured by UBM was 854±61 (central), 994±58 (superior), 930±57 (temporal), 979±55 (inferior), and 898±48 (nasal). CT measured by UBM was greater than that measured by ultrasonic pachymetry at all locations and was statistically significant at all locations except inferior (p=0.0006-0.048). No sex nor age effect was detected for CT at any location. The repeatability of ultrasonic pachymetry was superior to that of UBM. Mean±SD ACD was 5.74±0.41mm. A weak positive correlation was identified between central CT and IOP and between central CT and axial globe length. Normal data for CT and ACD of the adult horse obtained using UBM are provided. CT determined by UBM was greater relative to pachymetry at all corneal locations.

Ultrasound, Dacryocystorhinography and Morphological Examination of Normal Eye and Lacrimal Apparatus of the Donkey (Equus asinus)

Simple SummaryThe role of the eye with lacrimal apparatus as a vital organ of the donkey’s body still needs to be emphasized. The lacrimal gland (LG) is anatomically located at the dorsolateral aspect of the orbit within the lacrimal fossa, and responsible for secretion of the aqueous portion of precorneal tear film. Tears are drained to the exterior through the nasolacrimal duct (NLD), which starts from two puncta lacrimalis at the medial canthus and opens into nasolacrimal sac, and ends by the nasolacrimal orifice (NLO) at the nostril of both sides. Congenital or acquired obstruction of this duct frequently occurs in horses and leads to epiphora. Therefore, the aim of the present study was to investigate the normal macromorphological and ultrasonographic features of the eye and lacrimal gland, as well as normal dacryocystorhinography of the donkey (Equus asinus) in Egypt. The results illustrated the ultrasonographic biometric values of the eye, as well as the shape and size of the lacrimal gland. In addition, dacryocystorhinography and normal dissecting anatomy of the lacrimal apparatus was illustrated. The results of this study may act as the baseline for proper management of conditions of the eye and lacrimal apparatus in the donkey in the future.The study investigated normal macromorphological and ultrasonographic features of the eye and lacrimal gland, as well as normal dacryocystorhinography of the donkey (Equus asinus) in Egypt. A total of 36 donkeys of different ages, weights, and sexes were included in the study: 21 live animals for ultrasonography and dacryocystorhinography, and 15 cadaver skulls for morphological anatomy of the lacrimal apparatus. The ultrasound biometric values of the eye were 33.7 ± 1.7 mm for axial globe length (AGL), 39.8 ± 2.1 mm for globe diameter (GD), 10.8 ± 0.7 mm for lens thickness (LT), 3.2 ± 0.7 mm for anterior chamber depth (ACD), and 19.3 ± 1.6 mm for vitreous chamber depth (VCD). The lacrimal gland was recognized as a hypoechogenic structure with an anechoic core, located at the dorsolateral aspect of the orbit, and ovoid in shape. The mean NLD length was 193.0 ± 9.8 mm by radiography and 206.0 ± 20.4 mm by gross assessment. One NL orifice (NLO) was noticed on each side, with a diameter of 3.0 ± 0.1 mm and located 12.1 ± 2.1 mm from the dorsal commissure of the nostril. These results may act as the baseline for proper management of conditions of the eye and lacrimal apparatus in the donkey in the future.

A study on ocular ultrasonography in small ruminants

A study was conducted to find normal value of echo-morphometric view of inner ocular structure of healthy eyes of adult females of Magra sheep (n=10) and Marwari goats (n=10) by ultrasonography. In ultrasonogram, eyes appeared as well-defined, ovoid structures with mostly anechoic contents. The cornea, anterior and posterior lens capsule, scleroretinal rim and iris appeared hyper-echoic, whereas aqueous chamber, lens nucleus and vitreous chamber were anechoic. The optic disc was also distinctly seen. Average values of aqueous chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and axial globe length (AGL) recorded in the eyes of sheep were 2.95±0.05, 8.41±0.08, 10.10±0.16 and 21.64±0.23 and of goats were3.15±0.05, 9.44±0.07, 10.04±0.14 and 22.71±0.16 mm, respectively. The overall ACD, LT and AGL were significantly (p<0.01) lower in sheep than goats. The normal value of echomorphometric view of inner ocular structure of healthy eye of adult females of sheep and goats obtained can be used to evaluate clinical conditions.

The crested caracara (Caracara plancus) eye: Morphologic observations and results of selected diagnostic tests.

To provide a descriptive investigation about relevant features of the crested caracara's eye (Caracara plancus) and bony orbit, as well as provide data for ophthalmic tests. Morphological observations and the following diagnostic tests were performed: Schirmer tear test (STT), conjunctival flora evaluation, corneal touch threshold (CTT), intraocular pressure (IOP), central corneal thickness (CCT), B-mode ocular biometry, palpebral fissure length (PFL), and corneal diameter (CD) in 19healthy birds, plus two macerated skulls. Not all birds were used for each test. STT: 7.84±3.05mm/min; CTT: 2.46±1.10cm; IOP: 19.18±3.07mmHg; CCT: 0.31±0.02mm; PFL: 13.32±1.06mm; CD: 10.26±2.43mm; Axial globe length: 1.89±0.06cm; Anterior chamber depth: 0.27±0.06cm; Lens axial length: 4.55±0.06cm; Vitreous chamber depth: 1.2±0.07cm. The most frequent conjunctival bacterial isolates were Corynebacterium sp. (10/23.8%), Staphylococcus sp. (9/21.42%), Streptococcus sp. (7/16.6%), and E.coli (7/16.66%). The large lateral part of the palatine bone likely plays a role in the ventral protection of the globe against the impact of prey. Observed results are generally reflective of increased body mass compared to other Falconiformes, with values approaching those of similar sized Accipitriformes. These data may help veterinarians recognize peculiar morphologic features and perform a more accurate diagnosis of eye diseases of this avian species.

Relationship of the cornea and globe dimensions to the changes in adult human crystalline lens diameter, thickness and power with age

It is well known that human crystalline lens shape, dimensions and optical properties change throughout life and influence whole eye refraction. However, it is not clear if lens properties are associated with other ocular parameters. The purpose of the present study was to investigate the relationship of corneal and external globe dimensions with adult lens diameter (LD), lens thickness (LT) and lens power (LP) in order to determine if external factors influence lens properties. Postmortem human eyes (n = 66, age = 20–78 years) were obtained from the Ramayamma International Eye Bank, Hyderabad, India. Globe antero-posterior length (GAPL) and mean (average of horizontal and vertical) diameters of cornea (MCD) and globe (MGD) were measured using digital calipers. Eyes were dissected to produce ocular structures that contain the lens maintained in its accommodating framework, including intact zonules, ciliary body and sections of sclera. Specimens were mounted in a mechanical lens stretching system. LD, LT and LP were measured using high magnification retro-illumination photography, slit illumination photography and Scheiner principle-based optical system respectively in the unstretched (accommodated) state. Relationships between external globe and corneal dimensions and LD, LT or LP were assessed by multiple regression analysis. Age (0.012 ± 0.003 mm/year; p<0.001) and GAPL (0.185 ± 0.045 mm/mm; p<0.001) were significant (p<0.0001) predictors of LD. After adjusting for age-related increases, LD appears to be positively correlated with GAPL. Age (0.010 ± 0.004 mm/year; p = 0.009) and GAPL (−0.143 ± 0.060 mm/mm; p = 0.02) were significant (p = 0.001) predictors of LT. After adjusting for the age-related increase, LT appears to be negatively correlated with GAPL. Only age was a significant predictor of LP (−0.26 ± 0.04 D/year; p<0.001). The results suggest that, apart from aging, lens diameter and thickness are dependent on the anteroposterior length of the eye globe. Lens power is not influenced by globe dimensions.

Magnetic resonance imaging of the normal canine eye using a T1‐weighted volumetric acquisition

MRI is becoming increasingly available within the veterinary profession, and eyes are frequently included as part of a cranial study. The advantages of volumetric imaging are numerous, when compared to traditional two-dimensional imaging, and could be utilised within the veterinary setting. This report describing the normal MRI appearance of the canine eye, aimed to establish a standard reference range on a T1w volumetric acquisition. This study retrospectively assessed 62 eyes from 31 dogs that had undergone MRI at the Small Animal Hospital, Langford Vets, University of Bristol between 2016 and 2018 using a standardised MRI protocol. Dogs were excluded if they had presented with any reported ocular or orbital abnormalities. Measurements were performed from the 3D T1w volumetric sequence by a single observer using a previously published technique. Mean axial globe length was 2.13 cm and equatorial width 2.16 cm. Mean anteroposterior depth of the anterior chamber was 0.40 cm and 0.97 cm for the vitreous chamber. The mean anteroposterior and equatorial distance of the lens was 0.75 cm and 1.15 cm, respectively. Mean optic nerve width was 0.15 cm, and the mean width of the entire optic nerve sheath was 0.43 cm. Statistically significant relationships were noted between age and axial globe length and both lens dimensions. Highly significant relationships were noted between all variables, except lens dimensions and body weight Conclusion: This study provides reference values to assist in the interpretation of ocular structures during MRI on a T1w volumetric acquisition.

Comparison of computed tomographic ocular biometry in brachycephalic and non-brachycephalic cats.

Background and Aim:Ocular biometry has been used to evaluate ocular parameters; however, several factors need to be considered. In humans, age and sex have been shown to affect ocular biometry. The main factor that affects feline ocular biometry is the head circumference. At present, several reports have revealed that canine ocular biometry differs among dog breeds. However, there are no reports on normal ocular biometry in cats using computed tomography (CT). Therefore, this study aimed to explore feline ocular parameters between brachycephalic (B) and non-brachycephalic (NB) cats using CT and to evaluate the influence of age or sex of cats on ocular biometry.Materials and Methods:Twenty-four normal cats were divided into two groups: B (n=12) and NB (n=12). Each group had an equal number of designated males and females. CT was performed under mechanical restraint without general anesthesia and intravenous contrast enhancement. Ocular biometry, dimensions of the internal structure, including attenuation numbers and extra-ocular structures, were evaluated and compared.Results:B-cats had a significantly wider globe width (GW) than NB-cats (p<0.05). In addition, globe length (GL) and GW were significantly correlated with the age of the cats. Significant correlation between GL and age was observed in all cats (r=0.4867; p<0.05), NB-cats (r=0.8692; p<0.05), and B-cats (r=0.4367; p<0.05), whereas the correlation between GW and age was observed in B-cats only (r=0.7251; p<0.05). For extra-ocular structures, NB-cats had significantly greater orbital depth than B-cats (p<0.05), and orbital diameter was significantly correlated with age in all cats and B-cats (p<0.05).Conclusion:CT can be used for ocular biometric evaluation in cats with different skull types. GW was wider in B-cats, whereas the orbital depth was greater in NB-cats. Moreover, GW, GL, and orbital diameter were affected by the age of the cats. This information will be useful for further ocular diagnosis and treatment, especially in prosthetic surgical procedures.

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.

Trans-scleral plugs scleral fixation IOL and penetrating keratoplasty to restore vision in vitrectomized eyes.

To report the surgical outcomes of penetrating keratoplasty (PKP) and sutureless scleral fixation (SSF) using Carlevale Lens (Soleko) combined procedure to solve corneal failure and aphakia in vitrectomized eyes and discuss eventual advantages of this new approach. Two patients underwent primary wound repair and pars plana vitrectomy after a penetrating ocular trauma and were referred to the author's clinic. The PKP and SSF-Carlevale lens implantation were performed under retrobulbar anesthesia. Intraoperative and postoperative complications were recorded, intraocular lens positioning was evaluated using anterior segment optical coherence tomography (AS-OCT) and endothelial cell density was determined using an endothelial microscope. Both patients completed 12 months follow-up. The surgery was performed without intraoperative complications. After 1 month, the lens was fixed well, and the graft showed no sign of rejection. At the last visit after 12 months, the corneal graft remained transparent with good endothelial cell density in both cases; conjunctival scarring or inflammation and plugs externalization did not occur during follow-ups. Best-corrected visual acuity was 4/10 Snellen in the first case, while in the second case, we witnessed a limited visual recovery of 1/20 Snellen due to retinal issues. We report the feasibility of secondary IOL implantation using Carlevale with penetrating keratoplasty. The relative of ease of Carlevale lens implantation through the transscleral plugs reduces the open globe length resulting in a safer procedure, especially for vitrectomized eyes.