Ocular findings in two colonies of gray mouse lemurs (Microcebus murinus)

OBJECTIVE: To determine the incidence and describe the characteristics of cataracts and other ocular lesions found in two colonies of gray mouse lemurs (Microcebus murinus). ANIMALS STUDIED: A total number of 218 mouse lemurs (age range: 4 months-11 years) were included in this study. All individuals were property of the Muséum National d'Histoire Naturelle (France), and were housed either in Paris (colony #1: 75 animals examined), or in Brunoy (colony #2: 143 animals). METHODS: Ocular examinations were performed on all animals before and after pupil dilation, and included slit-lamp biomicroscopy and indirect ophthalmoscopy. In both colonies, a limited number of individuals were re-examined between several months and 2 years following the initial eye examinations. The eyes of five mouse lemurs with incipient or immature cataracts that died during this period were collected, and processed for routine histopathologic examination. RESULTS: A high incidence of cataracts was observed in both colonies (48% in colony #1; 21% in colony #2). Cataracts were predominantly bilateral, started in the anterior and/or posterior subcapsular area, and appeared to be slowly progressive. The earliest age at which lens opacities were observed was 3.5 years, and more than 50% of mouse lemurs over 7 years of age were diagnosed with cataracts. Complete cataracts led to blindness and were occasionally associated with other ocular lesions. CONCLUSION: We report a high incidence of acquired, slowly progressive, bilateral cataracts in two colonies of mouse lemurs (Microcebus murinus). Further studies need to be conducted to determine the cause of this disease in this species.     

Ophthalmic examination findings in a group of retired racing Greyhounds

OBJECTIVE: To characterize the frequency and types of ophthalmic findings in a group of retired racing Greyhounds. MATERIALS AND METHODS: Complete ophthalmic examinations of both eyes of 100 retired racing Greyhounds were performed. Anterior segment examinations were performed by slit-lamp biomicroscopy. Tear production was measured by Schirmer tear test. Intraocular pressures were obtained by applanation tonometry. The posterior segments were examined by binocular indirect ophthalmoscopy following pharmacologic dilation. A photographic record of abnormalities was obtained whenever possible. RESULTS: Mean tear production by Schirmer tear test was 21 mm/min (range 11-30 mm/min). Mean intraocular pressure by applanation tonometry was 16 mmHg (range 9-28 mmHg). The most prevalent anterior segment findings were cataracts (17% dogs, 11% eyes), corneal degeneration/scarring (6% dogs, 4% eyes), and suspected typical and atypical 'pannus' (total 4% dogs, 4% eyes). The most prevalent posterior segment abnormalities were vitreal degeneration (31% dogs, 38% eyes) and chorioretinal degeneration/scarring (7% dogs, 4% eyes). Other findings included anterior chamber vitreal strands, stretched lens zonules, periocular alopecia, a case of mild unilateral chemosis, and a distichium. CONCLUSIONS: Ophthalmic abnormalities are not uncommon in retired racing Greyhounds.     

迈克耳逊干涉实验的设计新思路

通过薄透镜测焦距的实验装置组装一台迈克耳逊干涉仪,能将几何光学实验顺利过渡到波动光学实验,该方法对充分合理开发实验室资源,深刻理解物理概念和不同实验装置的设计思路很有益处。     

Prevalence of feline cataract: results of a cross-sectional study of 2000 normal animals, 50 cats with diabetes and one hundred cats following dehydrational crises

Objective In this study 2000 normal cats, 50 cats with diabetes and 100 cats with a history of dehydrational crises were examined ophthalmoscopically to determine presence of cataract. Materials and methods The cats examined were predominantly from veterinary hospital populations but also from re‐homing facilities and breeding catteries. Prevalence of cataract was determined for different age groups (year cohorts). The age at which prevalence of cataract was 50% (C₅₀) was determined indirectly from a fitted prevalence curve as previously described. C₅₀ was determined for animals of different genders and different breeds as well as for those with diabetes and histories of dehydrational episodes related to chronic renal failure, chronic vomiting or chronic diarrhea. Results The mean ± standard deviation of C₅₀ for all normal cats in the study was 12.7 ± 3.4 years. All cats over 17.5 years were affected by some degree of lens opacity. C₅₀ for cats with diabetes was 5.6 ± 1.9 years (significantly different from normal cats at P < 0.0001). For cats with a history of dehydrational crises C₅₀ was 9.9 ± 2.5 (difference from normal cats nearing statistical significance at P = 0.06). Conclusion The study yields novel findings regarding the prevalence of age‐related cataract in normal cats together with cats with diabetes and history of previous dehydrational episodes in which prevalence of cataract is increased.     

CASE REPORT: Iridociliary melanoma with secondary lens luxation: distinctive findings in a long‐horned cowfish (Lactoria cornuta)

This report describes a long‐horned cowfish, which was diagnosed with buphthalmia and lens sub‐luxation in the right eye, conditions that progressed to complete anterior lens luxation and secondary keratoconus. Three months after the initial evaluation, a pigmented mass was observed protruding from the vitreous. An enucleation was performed under general anesthesia. Ocular histopathology revealed an iridociliary melanoma. Reports of intraocular melanomas are extremely rare in fish. To the authors’ knowledge, this is the first report of an iridociliary melanoma that led to buphthalmia, lens luxation, and keratoconus in a fish. Histological findings of lens luxation are also demonstrated. Due to the presence of a complex suspensory apparatus involving the teleost lens, this report speculates that lens luxation is a more devastating disease process in teleosts than in mammals.