Lens Rupture Research Articles

Phacoemulsification of cataract in the case of capsular bag damage

Purpose: to analyze the results of complicated cataract phacoemulsification with implantation of various types of intraocular lenses and fixation techniques. Material and methods. 48 patients (51 eyes) with complicated cataracts and weakened ligamentous apparatus of the lens or intraoperative rupture of the posterior lens capsule were divided into two groups: the study group I consisted of 21 patients (23 eyes, aged 71.4 ± 4.5 years) who had cataract phacoemulsification with an implantation of RSP-III IOL which was performed through a 2.4 mm small self-sealing incision using an injector and the control group II consisting of 27 patients (28 eyes, aged 73.6 ± 4.1 years) who had. Cataract phacoemulsification with an anterior chamber IOL implantation using an incision widened to 6.0 mm. Results. By the end of 1-year follow-up period, uncorrected visual acuity was 0.8 ± 0.1 in group 1 and 0.5 ± 0.1 in group II. In 100% of the patients of group 1 the correct position of the IOL was achieved in the early postoperative period (1–3 days) and maintained in the late period (1 year), whereas in group II, two eyes of 28 operated (7.14 %) showed a forward displacement of the anterior chamber IOL, which involved a contact with corneal endothelium. IOP stayed within the normal range in 21 eyes of group I patients (91.3 %), albeit two eyes (8.7 %) revealed transitory hypertension. In group II, 21 eyes (75 %) had normal IOP in the first three postoperative days, while 7 eyes (25 %) revealed an IOP increased to 29–30 mm Hg. In contrast to group I, group II patients showed induced corneal astigmatism which was decreasing during the follow-up period. Conclusion. In the case of a rupture of the posterior capsule during cataract phacoemulsification, or failure of the ligamentous apparatus of the lens of various origins, the implantation of the RSP-III IOL through a small self-sealing incision using an injector is the method of choice, which allows achieving a stable position of the IOL in the early and long-term follow-up periods, and high visual acuity with the minimal values of corneal astigmatism.

Pediatric Open Globe Injuries Caused by Firecrackers in a Tertiary Eye Care Hospital in Iran.

The aim of the study is to determine characteristic features of open globe injuries caused by firecrackers among pediatric population. In this retrospective cross-sectional chart review, medical records of children with ocular trauma who were hospitalized in Isfahan, Iran, during 2013-2017 were reviewed. We analyzed the collected data before and after propensity score (PS) matching. Of 396 pediatric patients with open globe injury, 22 injuries (5.9%) were caused by firecrackers. Hyphema, iris prolapse, and lens rupture were noted in 15 (68.18%), 10 (45.45%), and 2 (9.09) eyes, respectively. None of patients had endophthalmitis. The mean age of patients in firecracker group was higher and significant (11.86 ± 4.05 in firecracker vs 7.80 ± 4.68 in nonfirecracker, P < 0.001). Furthermore, most boys were in firecracker group (95.5%, P = 0.005). Patients in firecracker group resided more in urban areas (86.4%, P = 0.054) and had more intraocular foreign body (IOFB) in the eyes (40.9%, P < 0.001). After PS matching, patients in firecracker group had higher IOFB ( P = 0.008). In logistic regression models, patients with corneal lacerations had lower odds for long-time admission (≥4 days) than patients with both corneal and scleral lacerations in crude model (odds ratio, 0.35; 95% confidence interval, 0.17-0.69) and adjusted model (odds ratio, 0.37; 95% CI, 0.18 to 0.74). After PS matching, there was no significant association between risk factors and outcomes. The present study showed several differences between the pediatric open globe injuries caused by firecrackers and other mechanisms of injuries, including the age, sex, living place, presence of IOFB, and length of hospital stay.

Double Deletion of PI3K and PTEN Modifies Lens Postnatal Growth and Homeostasis.

We have previously shown that the conditional deletion of either the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), or its opposing phosphatase, phosphatase and tensin homolog (PTEN), had distinct effects on lens growth and homeostasis. The deletion of p110α reduced the levels of phosphorylated Akt and equatorial epithelial cell proliferation, and resulted in smaller transparent lenses in adult mice. The deletion of PTEN increased levels of phosphorylated Akt, altered lens sodium transport, and caused lens rupture and cataract. Here, we have generated conditional p110α/PTEN double-knockout mice, and evaluated epithelial cell proliferation and lens homeostasis. The double deletion of p110α and PTEN rescued the defect in lens size seen after the single knockout of p110α, but accelerated the lens rupture phenotype seen in PTEN single-knockout mice. Levels of phosphorylated Akt in double-knockout lenses were significantly higher than in wild-type lenses, but not as elevated as those reported for PTEN single-knockout lenses. These results showed that the double deletion of the p110α catalytic subunit of PI3K and its opposing phosphatase, PTEN, exacerbated the rupture defect seen in the single PTEN knockout and alleviated the growth defect observed in the single p110α knockout. Thus, the integrity of the PI3K signaling pathway was absolutely essential for proper lens homeostasis, but not for lens growth.

Open globe injury with lens rupture with rosette cataract

Open globe injury with lens rupture with rosette cataract

Creation of a New Explosive Injury Equipment to Induce a Rabbit Animal Model of Closed Globe Blast Injury via Gas Shock.

To establish a rabbit animal model of closed globe blast injury with an application of self-developed explosive injury equipment, we tend to explore the anatomic and pathological changes of eyes under different gas pressure. The device comprises of high-pressure air source compression pump, air channel, and gas shock. There were 36 healthy bluish blue rabbits exposed to one of five blast pressures (500, 1,000, 1,500, 2,000, and 5,000 Kpa). Slit lamp microscope, B-mode ultrasonography, fundus photography, optical coherence tomography (OCT), and intraocular pressure (IOP) examination were performed at 0-, 1-, 3-, and 7-days post exposure, while gross histopathology was assessed with H&E stain at 7 days. The contralateral eyes and non-blast exposed rabbits were used as controls. Definitive evidence of closed globe blast injury was obtained. Corneal edema and hyphema were observed in the models under all pressures with no full-thickness globe injury, or lens rupture, as the severity was pressure independent. There was no obvious retinal abnormality on B ultrasound or OCT scan, while light vitreous hemorrhage, commotio retinae, and heavy retinal pigmentation presented on one eye, respectively, in the eyes exposed to 5,000 Kpa. Increased retinal thickness with disorganizations on the retinal ganglion cell (RGC) layer and RGC apoptosis in groups under higher pressure (>500 Kpa). IOP of injured eyes were statistically decreased at day 1 and 7 post injury (p < 0.05). Conclusively, the rabbit animal model induced by self-developed equipment could mimic the clinical features of closed ocular blast injury successfully that was feasible and easy to operate. This will be a new rabbit animal model for investigating mechanisms and new therapeutic interventions of closed globe blast injury in the future.

Leukocyte chemotactic receptor Fpr1 protects against aging-related posterior subcapsular cataract formation.

Cataracts are a common consequence of aging; however, pathogenesis remains poorly understood. Here, we observed that after 3months of age mice lacking the G protein-coupled leukocyte chemotactic receptor Fpr1 (N-formyl peptide receptor 1) began to develop bilateral posterior subcapsular cataracts that progressed to lens rupture and severe degeneration, without evidence of either systemic or local ocular infection or inflammation. Consistent with this, Fpr1 was detected in both mouse and human lens in primary lens epithelial cells (LECs), the only cell type present in the lens; however, expression was confined to subcapsular LECs located along the anterior hemispheric surface. To maximize translucency, LECs at the equator proliferate and migrate posteriorly, then differentiate into lens fiber cells by nonclassical apoptotic signaling, which results in loss of nuclei and other organelles, including mitochondria which are a rich source of endogenous N-formyl peptides. In this regard, denucleation and posterior migration of LECs were abnormal in lenses from Fpr1-/- mice, and direct stimulation of LECs with the prototypic N-formyl peptide agonist fMLF promoted apoptosis. Thus, Fpr1 is repurposed beyond its immunoregulatory role in leukocytes to protect against cataract formation and lens degeneration during aging.

Spontaneous Lens Rupture in Congenital Cataract, Presented as Lens Fragment Within the Anterior Chamber

We report the case of a 60-year-old woman with a congenital anterior polar cataract who presented with a lens fragment within the anterior chamber of her left eye, without a medical history of surgery or trauma. Uneventful phacoemulsification with simultaneous removal of the lens fragment followed. Postoperatively, the patient’s visual acuity improved from a perception of light to 20/100. Histological examination of the lens fragment revealed persistent fetal vasculature, as well as fibrous metaplasia and extensive collagenesis. To our knowledge, this is the first report of spontaneous rupture of both the anterior capsule and the lens.

Requirement for Crk and CrkL during postnatal lens development

The Crk and CrkL adaptor proteins have SH2 and SH3 domains and play essential overlapping, as well as distinct, roles in many biological processes, ranging from cell structure and motility to proliferation. Conditional ablation of both Crk and CrkL in neuronal progenitor cells, using a Nestin-Cre transgene, resulted in severe defects in postnatal eye development, including progressive eye closure, lens rupture, and retinal malformation. These phenotypes were not observed in the presence of a single wild-type allele of either Crk or CrkL. We found that the lens in knockout mice started to rupture and disintegrate between postnatal days 7 and 12, although the structure of the retina was relatively well maintained. As the lens deteriorated further, the outer nuclear layer in the posterior of the retina enlarged and developed ruffles. Cre recombination occurred in the lens and retina of the knockout mice. Furthermore, the posterior lens capsule of the knockout mouse was thinner at postnatal days 0.5 and 3, suggesting that the defective lens capsule caused rupturing of the lens near the posterior pole. These results indicate that Crk and CrkL play essential overlapping roles in postnatal lens development.

B-Mode and Doppler Ocular Ultrasound Evaluation in Healthy and Positive Dogs for Visceral Canine Leishmaniasis

Background: The use of ultrasound examination in the evaluation of ophthalmopathies has been gaining more and more space within the ophthalmologic clinical routine. The hemodynamic study of ocular vascularization may anticipate future changes, aiding in the adequate establishment of therapeutic conduits. The objective of this study was to evaluate the structures of the ocular bulb and to perform the hemodynamic evaluation of the flow of the external ophthalmic artery of dogs with canine visceral leishmaniasis (CVL) correlating with healthy animals.Materials, Methods &amp; Results: For this purpose, 100 animals were used, of these 70 positive for CVL and 30 healthy animals, submitted to B-mode and Doppler ultrasound examination. Two-dimensional evaluation included identification of ocular changes and biometry of the following segments: axial length (M1), anterior chamber depth (M2), lens thickness (M3), lens length (M4), glass chamber depth (M5), optical disc length (M6) and optic nerve length (M7). The Doppler velocimetric evaluation included the identification and hemodynamic evaluation of the external ophthalmic artery, being measured: systolic peak velocity (SPV), final diastolic velocity (FDV), resistivity index (RI) and pulsatility index (PI). Ophthalmopathies were frequent in animals with leishmaniasis in both right (91.42%) and left (29.14%) eyes, with identification of capsular cataract, lens dislocation, retinal detachment and lens rupture. No significant statistical difference (P &gt; 0.05) was observed when comparing the biometric values between the right and left eyes of the animals with CVL, as well as for the measurements between healthy and CVL animals. Hemodynamic indexes of the flow of the external ophthalmic artery presented narrow limits for the right and left eyes of the positive animals, not statistically different from each other. However, a significant difference was observed when compared to hemodynamic evaluations of the flow of the ophthalmic artery between the right eyes of the group of normal animals and that of the carriers of leishmaniasis, with the latter presenting values superior to the first one. The B-mode and Doppler ultrasonographic evaluation enabled the morphological characterization of the ocular bulb, the identification of ophthalmopathies and the hemodynamic evaluation of the external ophthalmic artery of dogs with canine visceral leishmaniasis, establishing values that could be used in clinical ophthalmologic routine.Discussion: The presence of ocular changes diagnosed by B-mode ultrasonography were common in dogs with canine visceral leishmaniasis. Ocular lesions were observed in 80.5% of dogs with leishmaniasis, presenting a high frequency, corroborating with the results in the present research. In 22% of the animals, B-mode ultrasonographic lesions were identified in both eyes, 64 of these presented changes only in the right eye and 16 in the left eye. Ophthalmopathies can be uni or bilateral and cause more than one alteration in the same eye, resulting from both the immune-mediated mechanisms caused by the agent and direct parasitism. Although the literature reports that the highest frequency of lesions is bilateral, only 16 animals had alterations in both eyes. The origin of ophthalmopathies may be related to the species and tropism of the parasite, type and duration of the immune response developed by the host. The greater frequency of bilateral ophthalmopathies can have correlation with the systemic disease, in which in the initial stages of the disease only one eye is affected and the occurrence of bilateral manifestations is related to the chronic cases.

Intraocular foreign body injury in children: clinical characteristics and factors associated with endophthalmitis

Background/AimsTo analyse the clinical characteristics of intraocular foreign body (IOFB) injury in children and evaluate factors associated with endophthalmitis development.MethodsPatients aged <18 years with IOFB attending Zhongshan Ophthalmic Center between...

Uveitis and deficient lens capsules: Effect of glued intraocular lens on the visual outcome and the reactivation of inflammation.

Purpose:To evaluate the visual outcome and complication profile after glued intraocular lens (IOL) in post uveitic eyes.Methods:Patients with history of uveitis who had glued IOL with 3 months antecedent quiet anterior chamber (AC) were included in this prospective observational case series. Visual acuity, slit-lamp examination, fundus evaluation, optical coherence tomography, intraocular pressure, specular count and AC inflammation were analyzed before and after glued IOL procedure. Glued IOL eyes were also compared with their fellow normal capsular bag IOL.Results:Overall 17 eyes (50.7 ± 16.1 years) were analyzed. It included 41.8%, 23.5%, and 35.29% anterior, posterior, and pan uveitis, respectively. The etiologies were tuberculosis (23.53%), toxoplasmosis (11.77%), Fuch's heterochromic cyclitis (5.88%), HLA B27 (11.77%), psoriatic arthritis (5.88%), Rheumatoid arthritis (5.8%), sarcoidosis (11.77%), herpetic kerato-uveitis (5.88%), and idiopathic (17.65%). Cataractous subluxated lens (35.3%), aphakia (23.5%), decentered IOL (23.5%) and intraoperative capsular rupture (17.6%) were the surgical indications. A significant improvement in the mean uncorrected and best corrected visual acuity (P < 0.001) was recorded. The complications were IOL pigment dispersion (47%), macular edema (41%), and epiretinal membrane (24%). There was significant rise in AC reaction on day 1 (P < 0.001) and normal AC was attained by 88.2% eyes at 6 months. AC inflammation reactivation was noted in 11.7% of eyes. Though inflammatory reactivation was similar to the normal IOL, macular edema was higher in glued IOL.Conclusion:Glued IOL can cause inflammation in uveitis eyes which can be managed medically with minimal complications.

A survey of ocular ultrasound abnormalities in horse: 145 cases.

To describe the association of clinical and ultrasonographic (US) findings in horses affected by visual impairments, to estimate the most frequent ultrasonographic alteration as well importance and limits of US as a part of ophthalmic evaluation in equine patients. One-hundred-forty-five horses referred to the Veterinary Teaching Hospitals of the University of Perugia and Camerino for ocular problems were submitted to ophthalmic examination and ocular ultrasound. The following group of abnormalities was established: corneal alteration, cataract, synechiae, iris prolapse, anterior chamber alterations, vitreous opacities, globe reduction, globe enlargement, retinal detachment, lens subluxation/luxation, lens rupture, intraocular masses, retrobulbar masses. Specificity, sensitivity, positive and negative predictive value and related 95% confidence interval were calculated. Kappa value was estimated for concordance evaluation. A total of 384 clinical alterations were observed during ophthalmological examination, while 357 were found by ultrasound investigation. A very good agreement was found for lens subluxation/luxation, intraocular masses, iris prolapse, globe enlargement, lens rupture, vitreous opacities and cataract. Moderate agreement was found for retinal detachment, anterior chamber alterations and synechiae. Corneal alteration and globe reduction resulted in a fair and poor agreement, respectively. Ultrasonography affords the benefit of providing a complete cross-sectional view of the eyeball, facilitating the identification of ocular diseases in cases of loss of transparency of ocular media. It also represents an indispensable aid whenever anterior opacification precludes the use of ophthalmoscopic or biomicroscopic examination techniques.

Clinical observation on traumatic infectious endophthalmitis

Objective To observe the risk factors , clinical presentation and treatment of traumatic infectious endophthalmitis. Methods Eighty-nine eyes of 89 cases with open globe injury were collected.The relationship between endophthalmitis and age, sex, cause of injury, condition of wound, visual acuity, use of prophylactic antibiotics, the germiculture results, operation and postoperative visual acuity were analyzed. Results Infectious endophthalmitis occurred in 12 cases(13.48%). The result of single factor analysis showed that metal induced injury, selfsealing wound, perforating injury and corneal wound were risk factors for infectious endophthalmitis. Iris prolapse and systemic use of prophylactic antibiotics(2 or 3 generation of cephalosporins)were protective factors of infectious endophthalmitis.However, age, sex, intraocular foreign body, lens rupture and suture time whether in less than 24 hours had no obvious relations to the occurrence of infectious endophthalmitis.All patients with endophthalmitis underwent vitrectomy. After the operation, 11 cases (91.67%) had visual acuity of light perception to 0.02, and 1 case(8.33%) had visual acuity of 0.5. Conclusion Traumatic infectious endophthalmitis has poor prognosis and prevention is important. Systemic use of prophylactic antibiotics of high generation is recommended for ocular trauma combined with the following factors: metal injury, selfsealing wound, perforating injury and corneal wound. Key words: Endophthalmitis, infectious, traumatic; Antibiotics, prophylaxis; Injury, metal; Prolapse, iris; Treatment

A novel spontaneous mutation of BCAR3 results in extrusion cataracts in CF#1 mouse strain

A substrain of mice originating from the CF#1 strain (an outbred colony) reared at Osaka Prefecture University (CF#1/lr mice) develops cataracts beginning at 4weeks of age. Affected mice were fully viable and fertile and developed cataracts by 14weeks of age. Histologically, CF#1/lr mice showed vacuolation of the lens cortex, swollen lens fibers, lens rupture and nuclear extrusion. To elucidate the mode of inheritance, we analyzed heterozygous mutant hybrids generated from CF#1/lr mice and wild-type BALB/c mice. None of the heterozygous mutants were affected, and the ratio of affected to unaffected mice was 1:3 among the offspring of the heterozygous mutants. For the initial genome-wide screening and further mapping, we used affected progeny of CF#1/lr×(CF#1/lr×BALB/c) mice. We concluded that the cataracts in CF#1/lr mice are inherited through an autosomal recessive mutation and that the mutant gene is located on mouse chromosome 3 between D3Mit79 and D3Mit216. In this region, we identified 8 genes associated with ocular disease. All 8 genes were sequenced and a novel point mutation (1bp insertion of cytosine) in exon 7 of the Bcar3 gene was identified. This mutation produced a premature stop codon and a truncated protein. In conclusion, we have identified the first spontaneous mutation in the Bcar3 gene associated with lens extrusion cataracts. This novel cataract model may provide further knowledge of the molecular biology of cataractogenesis and the function of the BCAR3 protein.

Chemical microanalysis of mineral deposits on explanted hydrophilic acrylic intraocular lenses

to perform chemical microanalysis of mineral deposits on the surface of explanted hydrophilic acrylic intraocular lenses (IOL). Two soft IOLs made of hydrophilic acryl (one, however, hydrophobic surface coated) and explanted 3 and 6 years after implantation were examined by scanning electron microscopy (EVO LS10, "Karl Zeiss", Germany). Chemical composition of the lens surface was studied using an energy-dispersive spectrometer (EDS X-Max50, Oxford, Great Britain). Chemical microanalysis allowed identification of the deposits, which turned out to be non-stoichiometric hydroxylapatite (also, hydroxyapatite (HA)) crystals with zinc impurity (up to 1.4%weight). The two samples represent two stages of a single process. The early stage is associated with newly formed HA crystals that are unable to cause any significant changes to the lens surface. However, as spherocrystals grow, they exert a crystallization effort that moves their growth centers apart with subsequent lens rupture and deformation. Crystal morphology undergoes dynamic changes: while primary (newly formed) crystals are sheaf-like, mature are spheres. A growing HA is non-stoichiometric. Zinc abundance accounts for appearance of its separate mineral phase. Hydrophilic properties of acrylic polymer determine its high affinity for HA crystals. Hydrophobic coating (sample no.1) does not completely prevent lens opacification due to mineral deposits on its surface.

The optimal surgical timing and technique for pediatric traumatic cataract

Objective To explore the optimal surgical timing and technique for pediatric traumatic cataract.Methods 86 cases of pediatric traumatic cataract were recruited in the study and the surgical time was chosen based on the time after injury,degree of lens rupture and inflammatory reaction of uvea.Primary intraocular lens (IOL) implantation (group A) was performed in 68 eyes and secondary IOL implantation (group B) was performed in 18 eyes.Results 66 eyes (97.06％) in group A and 17 eyes (94.44％) in group B had best corrected vision better than 0.05 at 1 month after surgery.49 eyes (72.06％) in group A and 11 eyes (61.11％) in group B had best corrected vision better than 0.3 at 1 month after surgery.There were no significant differences between two groups (P ＞ 0.05).Conclusion Pediatric traumatic cataract with clear cornea and slight degree of lens rupture and inflammation can be treated by primary IOL implantation at 1 month after injury.The secondary IOL implantation can be performed in the patients with complicated ocular trauma or severe inflammation. Key words: Cataract, traumatic, pediatric ; Timing, surgical; Technique, surgical; Lens, intraocular

POSTTRAUMATIC ENDOPHTHALMITIS

To study predisposing factors of endophthalmitis in patients with open-globe injury. All 2,340 patients with open-globe injury admitted to our center over 5 years were studied retrospectively, and patients with endophthalmitis were compared with other patients. The number of endophthalmitis cases among patients with open-globe injury was 117 eyes, accounting for an incidence of 5.1%. The risk of endophthalmitis was significantly higher among male patients with pure corneal injuries (6.8%), intraocular foreign bodies (9.3%), traumatic lens rupture (7.1%), trauma resulting from needles (22.2%), and shorter lacerations. The existence of hyphema or iris prolapse was associated with lower rates of endophthalmitis. The mean gap between injury time and operation time was longer in the endophthalmitis group (2.1 ± 1.8 vs. 1.1 ± 1.3 days). Patients with endophthalmitis had significantly lower ocular trauma scores compared with other patients. Posttraumatic endophthalmitis is more likely among patients with open-globe injury that are needle related and among those who have intraocular foreign bodies, traumatic lens rupture, smaller wounds, or wounds exclusively in the cornea. Lower ocular trauma scores in this group of patients with penetrating trauma indicated a greater risk of poor visual prognosis. Therefore, it is suggested that necessary measures and immediate treatment be undertaken in high-risk patients.

Interaction between Connexin50 and Mitogen-activated Protein Kinase Signaling in Lens Homeostasis

Both connexins and signal transduction pathways have been independently shown to play critical roles in lens homeostasis, but little is known about potential cooperation between these two intercellular communication systems. To investigate whether growth factor signaling and gap junctional communication interact during the development of lens homeostasis, we examined the effect of mitogen-activated protein kinase (MAPK) signaling on coupling mediated by specific lens connexins by using a combination of in vitro and in vivo assays. Activation of MAPK signaling pathways significantly increased coupling provided by Cx50, but not Cx46, in paired Xenopus laevis oocytes in vitro, as well as between freshly isolated lens cells in vivo. Constitutively active MAPK signaling caused macrophthalmia, cataract, glucose accumulation, vacuole formation in differentiating fibers, and lens rupture in vivo. The specific removal or replacement of Cx50, but not Cx46, ameliorated all five pathological conditions in transgenic mice. These results indicate that MAPK signaling specifically modulates coupling mediated by Cx50 and that gap junctional communication and signal transduction pathways may interact in osmotic regulation during postnatal fiber development.

Genomic organization of the region spanning D14Mit262 and D14Mit86 on mouse chromosome 14 and exclusion of Adam28 and Adamdec1 as the cataract-causing gene, lr2

Mice with recessive cataract, CXSD, show the first clinical symptoms of cataract at five weeks, with complete penetrance. We previously localized the cataract-causing lens rupture 2 gene (lr2) to mouse chromosome 14. In the process of positional cloning of the lr2 gene, we determined the genomic organization of the critical region, defined by D14Mit262 and D14Mit86, and compared it to recently published map information. In addition, mutational analysis using reverse transcription polymerase chain reaction (RT-PCR) followed by direct sequencing as well as quantitative realtime PCR (RQ-PCR) was performed to investigate Adam28 and Adamdec1 as lr2 candidate genes in this study. There was no mutation cosegregating with the phenotype of CXSD mice, which excluded these genes as the lr2 gene. Identification of more transcripts from this region and their mutation analyses are required to isolate the lr2 gene.

Ocular Ultrasonography in Horses

Ocular ultrasonography is a practical and valuable examination tool for horse eyes with anterior opacities that preclude ophthalmoscopy of deeper structures. Ultrasonography is indicated in cases of periocular trauma, exophthalmos, corneal masses, corneal edema and/or infiltrates, cataracts, and anterior uveitis. Transducers of 7 to 10 MHz may be used to identify and characterize cataracts, lens luxation, lens rupture, vitreal opacities, retinal detachment, endophthalmitis, microphthalmos, buphthalmos, and periorbital masses. High-resolution ultrasonography, using frequencies of 20 MHz and greater, provides improved detail of anterior segment structures. Ultrasound image artifacts are common, requiring knowledge of ocular anatomy and basic ultrasonographic principles for accurate interpretation.