We did a light and electron microscope study of the infrared receptors in the labial pits of a python, Python regius. The receptors are elongated, tapering terminal nerve masses about 8 x 20 μm located immediately below the conified surface of the pit fundus. The receptors are surrounded and supported by epithelial cells, and together with these epithelial cells are renewed and sloughed off periodically with each molting cycle. Each terminal nerve mass is packed with mitochondria in numbers not seen in any other sensory organ. Beneath the receptors is a dense network of fine capillary vessels which probably serve both to supply the tremendous energy requirements of the mitochondria-rich receptors and to stabilize and control the thermal sensitivity of the receptors. In active terminals (as opposed to degenerating ones), the mitochondria show both energized and discharged states, as well as ladder-like junctions between individual mitochondria, which suggest that the mitochondria are intimately involved in producing the nerve impulse.

Forty-six apparently healthy newborn African green monkeys (Cercopithecus aethiops) were examined for the persistence and disappearance of the hyaloid artery with an opthalmoscopic camera. On the day of birth, the hyaloid artery was detected in all the newborn animals. Between 21 and 31 days of age, the hyaloid artery disappeared without exception. The persistence of the hyaloid artery in the newborns and its disappearance during an early period of life can be regarded as a normal phenomenon in the developmental process of infant African green monkeys.

WBN/Kob rats are a spontaneous diabetes animal model and develop a disturbance in the retinal photoreceptor cells at a young age. We studied the differences in retinal vascular architecture between young (14- to 23-week-old) and old (70-week-old) WBN/Kob rats and young (14- to 23-week old) and old (30-week-old) Wistar rats. Casts were prepared with Mercox CL-2R injected into the internal carotid artery.

No abnormal retinal vascular architecture was detected on the casts from Wistar rats at any age. However, narrowing of the venules and the imprints of particially stenosed capillaries were seen in 23-week-old WBN/Kob rats. Obvious depression of the venules at the arterio-venous crossing point and looseness of the capillary network were seen in 70-week-old WBN/Kob rats.

The anterior part of the eye was examined in 3,978 newborn cynomolgus monkeys. Three males (about 0.08%) out of these newborns were found to have white opacities in their both eyes. They were diagnosed as bilateral congenital cataract by observation with a slit-lamp biomicroscope. Breeding studies are needed to determine whether these cases have any genetic background.

Steroid glaucoma is difined as increase of intraocular pressure (IOP) instillation of steroidal drug. Ii is suggestied that this disease could begenetic. We attempted to establish the steroid glaucoma breeding among pigmented rabbits increased the IOP by instillation of steroid. Steroid was instilled to 65 rabbits twice daily. After 2 weeks, teenty five rabbit showed the increase of IOP. After 3 month, We tried to instille steroid to rabbits wishid incvesed IOP, But none of them showed the increse of IOP. These risults suggest that growth during the three month might caused elimination of response and consideration should be given to the setting of the study period.

The following experiments were carried out to determine whether applanation pneumatonograph (PTG) can be clinically applied to dogs as in cows and horses.

Experiment 1: Using freshly enucleated eyes from dogs, the in vitro intraocular pressure was directly manipulated, changing the pressure 5 mmHg at a time in the range of 0∼50 mmHg and 10 mmHg at a time in the range of 50∼100 mmHg. The correlation between the intraocular pressure and ocular pressure measured by PTG was investigated.

Results: There was a high correlation between the PTG-measured value and the true value of intraocular pressure in an enucleated eye in the range of 0∼100 mmHg (R²=0.980) and in the range of 0∼40 mmHg (R²=0.987). The results showed that the value measured by PTG is only slightly lower than the true value of intraocular pressure.

Experiment 2: Ophthalmotonometry was carried out on 1,016 eyes of 525 dogs during the first examination of dogs brought to our veterinary hospital over a period of 4 years and 9 months from October 1990 to July 1995. Gelatt et al. carried out a comparative study according to the type of disease, and age, breed and sex of dogs of PTG-measured intraocular pressure and true intraocular pressure, using 15∼25 mmHg as the standard value. They also carried out acomparative investigation with no standard value for different diseases.

Results: The average ocular pressure using PTG was 18.6±3.2 mmHg, and was less than 20 mmHg in the age, breed and sex groups. However, in the disease group, the number of diseases in which intraocular pressure was less than 15 mmHg increased from 8 to 12 with the introduction of a standard value. Most of the cases were in the range of 10∼15 mmHg, and the lowest limit in the normal range was estimated to be around 10 mmHg.