The exact etiology and pathogenesis of myopia are not known yet, although various studies of the development of myopia in experimental animals have been made. Authors attemtped whether rabbits developed axial myopia by fusing their lids at birth in one eye, or not. The monocular vision was deprived by suture of upper and lower lids in 12 rabbits which were 5 day-old. The other eye was unsutured as the control. Ten months later, we assessed refractive error, corneal curvature, axial length, and intraocular pressure and enucleation was done. We observed the histologic change of sclera with light microscope. The eyes with lid suture were more myopic(-3.35 +/- 0.99D) than the controlled eyes(-0.21 +/- 0.46D) (p<0.01). The corneal curvature and intraocular pressure were not significantly different between two groups. The axial lengths of the sutured eves were increased(21.27 +/- 1.70mm) in comparison with those of the controlled(17.39 +/- 1.83mm)(p<0.01). We conclude the difference in axial length was caused by the elongation of the posterior segment of eyeball. since lens thickness, depth of anterior chamber, and corneal curvature were identical in both groups. These were correlated with histologic change that showed thinner posterior parts of sclera of the sutured eyes than those of the controlled eyes. The results of this study demonstrate that monocular lid fusion in rabbits produced an expenmental axial myopia.
Animals ; Anterior Chamber ; Eyelids* ; Intraocular Pressure ; Myopia* ; Parturition ; Rabbits* ; Refractive Errors ; Sclera ; Sutures* ; Vision, Monocular

PURPOSE: To analyze the results of treatment in pure anisometrpic amblyopia with unilateral visual acuity of 0.1 or worse. METHODS: The major eligibility criteria included pure anisometropic amblyopia with age <10 years, best-corrected visual acuity 0.1 or worse in the worse eye and 0.5 or better in the good eye after the wearing of optimal spectacle correction for a minimum of 4 weeks, and the minimum follow-up was 6 months. Twenty-one patients were selected and we analyzed the age at the amblyopia treatment, the type and degree of anisometropia, and the final visual acuity after treatment for visual improvement. Successful treatment was defined as a final visual acuity of 0.3 or more. RESULTS: The mean age at treatment was 5.2 years. The types of anisometropia were hypermetropic in 14 patients, astigmatic in 4, and myopic in 3. The mean duration of treatment of amblyopia was 16 months, and 13 of 21 children with pure anisometropic amblyopia achieved 0.3 or better. The age at treatment was younger and the compliance rate was higher in the success group than in the failure group. CONCLUSIONS: The most common type was hyperopic in the pure anisomteropic amblyopia. Compliance and age at treatment were significantly related to best visual acuity attained in pure anisometropic amblyopia with unilateral visual acuity of 0.1 or worse.
Amblyopia ; Anisometropia ; Child ; Compliance ; Eye ; Follow-Up Studies ; Humans ; Hyperopia ; Vision, Monocular ; Visual Acuity

In anesthetized rabbits, the superior oblique muscle was excited by stimulation of a vestibular canal nerve. Induced reflex ocular movements were observed by the naked eyes, and were recorded by means of nystagmographic and oculographic techniques. Superior oblique muscle contraction induced by stimulation of a vestibular canal nerve produced ocular incycloduction associated with elevation. The elevatory action of superior oblique muscle was also demonstrated by means of the nystagmographic recording. Contraction of the superior oblique muscle caused augmented incycloduction in adduction of the eyeball, whereas excitation of the muscle produced augmented elevation in abduction of the eyeball. When these eye movements produced by the superior oblique muscle are compared to those of Tokumasu et al. observed in monkey and cat, the direction of the rotatory action appears to be contradictory. Such phenomenon may be ascribed to the anatomical differences of the oblique muscles in these animals endowed with the binocular or monocular vision.
Animals ; Cats ; Eye Movements ; Haplorhini ; Muscle Contraction ; Muscles ; Rabbits* ; Reflex ; Telescopes ; Vision, Monocular

PURPOSE: To evaluate the clinical usefulness of binocular multifocal electroretinography (mfERG) by comparing results with conventional monocular mfERG in patients with monocular macular disease. METHODS: mfERG testing was conducted on 32 patients with monocular macular disease and 30 normal subjects. An initial mfERG was simultaneously recorded from both eyes with two recording electrodes under binocular stimulation. A second mfERG was subsequently recorded with conventional monocular stimulation. Amplitudes and implicit times of each ring response of the binocular and monocular recordings were compared. Ring ratios of the binocular and monocular recording were also compared. RESULTS: In the macular disease group, there were no statistical differences in amplitude or implicit time for each of the five concentric rings between the monocular and binocular recordings. However, with binocular simulation, the ring ratios (ring 1 / ring 4, ring 1 / ring 5) were significantly reduced in the affected eye. In the normal control group, there were no statistical differences in any parameters between the monocular and binocular recordings. CONCLUSIONS: Binocular mfERG could be a good alternative to the conventional monocular test. In addition, given that the test needs stable fixation of the affected eye during the binocular test, the reliability of the test results could be improved, especially for patients with monocular macular disease.
Adult ; Aged ; Aged, 80 and over ; Electroretinography/*methods ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Vision, Binocular/physiology ; Vision, Monocular/physiology ; Visual Acuity/*physiology ; Wet Macular Degeneration/*diagnosis/*physiopathology

A 50-year-old woman, who had been treated for rheumatoid arthritis (RA) over a 10-year period, suddenly presented with monocular vision loss while the RA had a stable course over many years. She was diagnosed with central retinal artery occlusion (CRAO) based on ophthalmologic examinations including optical coherence tomography and fluorescein angiography. There was no evidence of atherosclerosis, infection, and malignancy that can cause CRAO. Considering the association between CRAO and other rheumatic diseases, such as systemic vasculitis and systemic lupus erythematous in previous reports, it was presumed that her RA might have contributed to the development of CRAO. Although cases of CRAO in patients with RA are extremely rare, these findings suggest that physicians need to be aware of the possibility of CRAO in patients with RA who experience decreased visual acuity.
Arthritis, Rheumatoid* ; Atherosclerosis ; Female ; Fluorescein Angiography ; Humans ; Middle Aged ; Retinal Artery Occlusion* ; Retinal Artery* ; Rheumatic Diseases ; Systemic Vasculitis ; Tomography, Optical Coherence ; Vision, Monocular ; Visual Acuity

Presbyopia is an age-related condition that progressively decreases the ability to focus on near objects. Minimally invasive surgical techniques have been developed to improve near vision, including laser in situ keratomileuses (LASIK) and corneal inlay. Most have similar approaches using monovision or increasing the depth of focus. Monovision laser refractive surgery is a combination of conventional LASIK, LASIK which creates a multifocal cornea (central near or peripheral near) and aspheric micro-monovision LASIK with a special ablation profile, which develops spherical aberration. Conductive keratoplasty is a method that uses radiofrequency energy to shrink the mid-peripheral corneal stromal tissue. However, it is not used because of regression. A corneal inlay is a small device that is implanted in the corneal flap or pocket made by a femtosecond laser. It is inserted into the non-dominant eye. There are various inlays such as the Flexivue Microlens (refractive), Raindrop (corneal shape-changing), and KAMRA (small-aperture) inlays. However, the safety and effectiveness of these inlays have not been proven over a long follow-up period, so care is required when performing inlay implantation. All presbyopia treatments can improve near vision but also have limitations and side effects such as reduced far vision, contrast sensitivity, or increased glare. Therefore, it is essential to select patients carefully. Mechanisms associated with presbyopia are not fully understood, and presbyopia remains challenging for ophthalmologists.
Contrast Sensitivity ; Cornea ; Corneal Transplantation ; Follow-Up Studies ; Glare ; Humans ; Inlays ; Keratomileusis, Laser In Situ ; Methods ; Presbyopia ; Refractive Surgical Procedures ; Vision, Monocular

Retinoblastoma is the most common intraocular malignancy in childhood. Diagnosis is currently made by ophthalmologists under general anesthesia as it is the gold standard for intraocular assessment. However, evaluations for extraocular disease are also necessary. Treatment strategies vary according to the disease status. If a single eye is involved, the treatment goal is oriented to the removal of the tumor and prevention of relapse. In bilateral retinoblastoma, the main treatment goal is to save monocular vision and save life. This article will explore the available treatment options for retinoblastoma including enucleation, radiotherapy, local therapy, intravenous chemotherapy, intra-arterial injection and intra-vitreal injections. There were recent advances in our understanding on the genetic pathophysiology of the retinoblastoma protein gene in tumorigenesis, which may help developing future treatment. Early detection of retinoblastoma is important for prolonging survival and improving quality of life.
Anesthesia, General ; Carcinogenesis ; Diagnosis ; Drug Therapy ; Injections, Intra-Arterial ; Quality of Life ; Radiotherapy ; Recurrence ; Retinoblastoma Protein ; Retinoblastoma ; Stem Cell Transplantation ; Vision, Monocular

OBJECTIVE: To explore the expression of cyclic guanine monophosphate (cGMP) and the ultrastructure change in retina of guinea pig with form-deprivation myopia and the underlying mechanisms. METHODS: Three-weeks-old guinea pigs were distributed in 3 groups: an untreated group (Group I), a myopia 2-weeks group (Group II) and a myopia 3-weeks group (Group III), animals underwent monocular form-deprivation by facemask for 2 and 3 weeks. The right eyes were deprived and the left eyes were self-controlled. The refraction and axial length of the eyes was measured. Retina was observed by electron microscope. The expression of cGMP was detected by radioimmunochemistry. RESULTS: Deprived eyes in guinea pig showed significant development of myopia, the refraction and axial length was increased. The pathological changes in ultrastructure of retina were aggravated with the development of myopia. The expression of cGMP was significantly up-regulated in the deprived eyes compared with self-control eyes(P<0.05). CONCLUSION Form-deprivation can up-regulate the expression of cyclic GMP, which might play an important role in the development of myopia.
Animals ; Cyclic GMP ; metabolism ; Disease Models, Animal ; Female ; Guinea Pigs ; Male ; Myopia ; etiology ; metabolism ; pathology ; Random Allocation ; Retina ; metabolism ; ultrastructure ; Sensory Deprivation ; Vision, Monocular ; physiology