The lens is an intraocular structure located posteriorly to the iris (colored part of the eye). Cataracts consist of an opacification of the lens and frequently occur in adult and senior pets, although they can occur at any age. Regarding their cause, cataracts can be congenital, hereditary or secondary to other problems, such as diabetes or other eye problems (inflammation, trauma). In addition to dogs and cats, this disease also frequently occurs in horses, for which we also have the means to diagnose and treat it. Diagnosis is obtained through a complete ophthalmological examination, and the only current available treatment is through a surgical technique denominated phacoemulsification, which consists of destruction the cataract using ultrasound. Subsequently, a new transparent intraocular lens is placed to replace the crystalline lens and restore the patient’s vision. The surgical success rate is high, around 90 to 95%.
The lens is an intraocular structure that is located posterior to the iris. Cataracts consist of an opacification of the lens.
Regarding their cause, cataracts can be congenital, hereditary or secondary to systemic diseases, such as diabetes or other eye problems (uveitis, trauma). Congenital cataracts are generally non-progressive and are formed during fetal lenticular development. For this reason, they are mostly diagnosed in the first months of the pet’s life and especially in breeds such as Miniature Schnauzer, Boston Terrier and West Highland White Terrier. Additionally, congenital cataracts may have maternal origin, when resulting from in utero exposure to toxic or infectious agents. Hereditary cataracts are the most frequently diagnosed, especially in adult and senior animals. To this day, the exact pathogenesis associated with the formation of hereditary cataracts is not known, but their anatomical location, progression, bilateral nature, and absence of other identifiable causes allow their presumptive diagnosis. Diabetes mellitus is often associated with the rapid development of symmetrical cataracts, due to changes in the metabolic pathways of the lens. These changes result in its intumescence, which is associated with an increase in the leakage of proteins from the lens and a greater risk of its rupture.
In addition to dogs and cats, this disease also occurs frequently in horses, for which we also have the means to diagnose and treat it.
Lens-induced uveitis is present in almost all stages of cataracts and is caused due to leakage of proteins from the lens into the anterior chamber. Common signs of anterior uveitis are miosis, low intraocular pressures, Tyndall effect and episcleral congestion. Anterior uveitis puts the eye at risk of blindness and painful complications, such as iris-to-lens adhesions, glaucoma, lens dislocation, and retinal detachment.
Diagnosis is obtained through slit lamp biomicroscopy, and the only treatment that currently exists is through a surgical technique denominated phacoemulsification, which consists of destruction of the cataract using ultrasound. Subsequently, a new transparent intraocular lens is normally placed to replace the crystalline lens and restore the animal’s vision. Most animals regain some vision the day after surgery, but it often takes a few weeks for vision to fully recover as post-surgical intraocular inflammation subsides.
The surgical success rate is high, around 90 to 95%, and this is closely related to the speed of diagnosis after the development of cataracts, and subsequent control of lens-induced uveitis. Therefore, these cases should be referenced as briefly as possible.