Relação da pressão intra-ocular e paquimetria corneal com os diferentes estágios de desenvolvimento das cataratas diabéticas e não diabéticas em cães da raça Poodle / Relationship of intraocular pressure and corneal thickness to diabetic and nondiabetic cataracts in Poodles
AUTOR(ES)
Milena Sefrin Helzel
DATA DE PUBLICAÇÃO
2008
RESUMO
Diabetes mellitus (DM) causes different alterations in all corneal layers, such as deficient control of hydration, what makes them prone to decompensate after injury. Lens induced uveitis (LIU) occurs mainly in dogs presenting hypermature cataracts, what causes irreversible damages to the corneal endothelium and may lead to stromal edema, usually transient. DM dogs are particularly predisposed to cataract with LIU associated. Intraocular pressure (IOP) and pachymetry measurements may be useful procedures capable to detect such alterations. The aim of this study was to determinate the relationship between intraocular pressure and pachymetry on diabetic and nondiabetic Poodles, presenting different stages of cataracts. One hundred twenty-two Poodles, 134 females and 99 males, with ages varying from 2 to 16 years, were admitted at the Ophthalmology Service, of the Veterinary Hospital, of the University of São Paulo. After complete identification of the animals, anamnese (time of DM and cataract formation) and ophthalmological exam, dogs were included in the study. Dogs affected by other systemic diseases inducing ocular manifestation or other primary ocular alteration were excluded. LIU was diagnosed by observation of congestion of the episcleral vases and resistence to midriasis after induction with Mydriacyl®. IOP was measured by TonoPen-XL® and pachymetry by PachPen® after instillation of anesthetic eyedrop (Proximetacaine 0,5% - Anestalcon, Alcon). Statistical comparison between factors were made using Spearman, Mc-Nemar and Mann-Whitney tests when appropriated. The distributions of the factors among the groups were compared by Krusskal-Walliss test, and when significant, Dunns test was used to describe the differences found. The level of significance was set at p<0,05. Two hundred thirty-three eyes of 122 Poodles were evaluated. Eyes were classified in different groups: healthy dogs without cataracts (n=39); dogs presenting incipient cataract (n=20); with immature cataracts (n=29); mature cataracts (n=20); or hypermature cataracts (n=80); DM dogs presenting immature cataract (n=9); DM with mature cataracts (n=11); and DM with hypermature cataracts (n=25). Distribution of factors, such as age, sex, weight, time of DM and cataract, presence of LIU, IOP and pachymetry were statistically different between groups. Female Poodles were more affected by diabetic cataract and diabetic dogs were older than the other ones. IOP was statistically lower and LIU alterations more prevalent in the hypermature cataract groups (diabetic and no diabetics). IOP was negatively correlated to age and pachymetry measures. Pachymetry was positively correlated to age and weight. Negative correlation was observed between pachymetry and time of cataracts formation. LIU eyes presented lower IOP and higher pachymetry. The difference found at pachymetry and IOP measurements in LIU and non LIU eyes were 60 µm and 2 mmHg respectively. In diabetic dogs, pachymetry was particularly higher and LIU particularly present. The higher corneal thickness may possible be related to the sum of alterations caused by DM and LIU to those corneas. Hypermaturity was directly related to LIU. We concluded that pachymetry and IOP measurements are important procedures to the LIU diagnosis, mainly when negatively correlated.
ASSUNTO(S)
dogs catarata diabetes mellitus intraocular pressure diabetes mellitus pressão intra-ocular cães paquimetria cataracts pachymetry
