Several surgical options for the correction of astigmatism have been advocated, such as laser in situ keratomileusis, photorefractive keratectomy, astigmatic keratotomy using limbal or corneal relaxing incisions, and a toric phakic or pseudophakic intraocular lens implantation. Moreover, it has been estimated that approximately 30%, 8%, and 3% of patients have more than 1, 2, and 3 diopters (D), respectively, of preexisting cylindrical refractive errors. IntroductionĪlthough modern refractive and cataract surgery techniques allow rapid visual recovery, preexisting corneal astigmatism remains a common change to achieve excellent uncorrected visual acuity. It may be necessary to correct the preexisting astigmatism to acquire excellent visual performance, especially in astigmatic eyes with larger pupils. Eyes with larger pupils had lower optical quality even when they were astigmatic. Multiple comparisons demonstrated a significant difference between measurements made for a 2-mm pupil and for a 6-mm pupil at each diopter of astigmatism ( for 0, 1, 2, and 3 D, Dunnett test) and those made for a 4-mm pupil and for a 6-mm pupil at each diopter of astigmatism ( for 0 D, 1, 2, and 3 D). They also decreased significantly with an increase in pupil size at each diopter of astigmatism ( for 0, 1, 2, and 3 D). The MTF cutoff frequency and the Strehl2D ratio decreased significantly as the amount of astigmatism increased at each pupil size ( for 2, 4, and 6 mm, analysis of variance). After we fully corrected cycloplegic refraction, we created with-the-rule astigma tism of 1, 2, and 3 diopters in these eyes and then quantitatively assessed the modulation transfer function (MTF) cutoff frequency and the Strehl2D ratio with 2-, 4-, and 6-mm pupil sizes using the Optical Quality Analysis System. We examined twenty-two eyes of 22 healthy volunteers (mean age ± standard deviation, years) who had no ophthalmic diseases other than refractive errors (manifest cylinder ≤0.25 diopters (D)). To objectively determine the effects of pupil size on optical quality parameters in astigmatic eyes using a double-pass instrument. If your pet is not improving, and/or there is development of additional clinical signs, contact your veterinarian.Purpose.Administer any prescribed medication as directed by your veterinarian.Antibiotics and/or anti-inflammatory drugs may be recommended for certain bacterial or inflammatory disorders.No treatment may be needed in disorders such as iris atrophy or hypoplasia, in which the iris is underdeveloped or decreased in size.Your veterinarian might recommend several treatments while results regarding an underlying disorder are pending. It is difficult to treat patients with anisocoria symptomatically, as there can be multiple underlying causes that are treated in very specific ways. Treatment of Anisocoria (unequal pupil sizes) in Cats Computed tomography (CT) scan or magnetic resonance imaging (MRI).Visual evoked potential (VEP) to evaluate optic nerve and brain function.
Anterior uveitis (inflammation of a portion of the eye).Disorders of the optic tract, a bundle of nerve fibers associated with the eye.
Disease of the cerebellum, a portion of the brain.Disorders of the oculomotor nerve, a cranial nerve that provides muscle sense and movement of the eye.Disorders of the optic nerve, the primary nerve to the eye.Nervous system abnormalities, as well as infection, inflammation, cancer or trauma involving the eye can also result in anisocoria. Anisocoria is an inequality of pupil size, when one pupil is dilated and the other is constricted.