VN September 2020

Vetnews | September 2020 33 6. The size of the pupil is not a good assessment of prognosis. Obviously, globes showing a good direct pupil response and consensual pupil response have a more favourable prognosis. Miosis which is a good sign, frequently may be due to ocular pain and not a result of visual stimulus or assessment of vision. Amassivedilated, non-responsivepupil could suggest optic nerve damage. The reasons for choosing enucleation immediately are usually obvious for the clinician but if not, then it is recommended that an attempt be made to replace the globe back in the orbit, place a temporary tarsorrhaphy, andprovidemedical therapy. At the re-evaluation of such a case one could have a visual or blind eye that could be cosmetically salvaged, or the decision could be to enucleate the globe. A recent article published discusses the range of prognostics factors and throws some light on the concept of proptosis. [ Veterinary Ophthalmology 2020: 23: 245-251]. The following findings were noted; 1. The time between the prolapse and the admission is not correlatedwith vision at the last recheck. 2. Most proptosis cases involve brachiocephalics, but when visual outcomes were compared against non-brachiocephalics, the cephalic index was not correlatedwith vision at the last recheck. 3. The cause of the proptosis was not correlatedwith vision at the last recheck. 4. The presence of a direct PLR at admission was correlatedwith vision at the last recheck. 5. The presence of an indirect PLR at admission was correlatedwith vision at the last recheck. 6. No specific systemic post-operative therapy [antibiotics and anti- inflammatories] had a significant effect on outcome. 7. Topical treatment likewise had no significant effect on outcome. The prognosis for vision after a traumatic proptosis remains guarded and when data is compared from the only three studies on this topic, vision is seen in 28-41% of cases where globes were replaced. The presence of a direct PLR at initial examination is a good prognostic indicator as it implies some nerve pathways are functional and 85% of dogs would be visual at the final recheck. 88% of eyes that lack a consensual PLR at presentation would be blind at recheck. So, howdo you treat a proptosis: When the decision has been made to salvage the globe, the procedure is performed under general anaesthetic as soon as possible. Up until this time the globe should be kept moist with an antibiotic ointment. Once anaesthetized,theglobeshouldbewashedcleanandtheeyelidsshouldbe grasped with a forceps or a strabismus hook and held upwards and away from the globe to allow the globe to gently pushed back so that it settles into the orbit. In some cases, a lateral canthotomymay be required to gain a larger palpebral opening before the globe can be repulsed. A temporary tarsoraphy is performed using nylon sutures. Two to three sutures are usually sufficient.The suture is placed through the lids and exits at the level of themeibomianglands. Ensure thenylondoesnotpenetrate through the palpebralconjunctivaasthiscouldresultinthenylonbeingindirectcontact withthecornealsurface.Themedialcanthusareashouldbeleftopensothat antibioticdropsorointmentand/orlubricantssuchasTeargelorOptivePlus canbeapplied.Systemicantibioticandanti-inflammatoriesshouldbeused. Sutures should remain inplace for at least 7-14days and then removedone at a timestarting fromthemedial canthal side. Long-term sequelae of proptosis include blindness, strabismus, lagophthalmos, sensory deficit of the cornea, keratoconjunctivitis sicca, exposure keratitis, glaucoma, and phthisis bulbi. Exotropia is a common sequel resulting from avulsion of the medial rectus muscle. Globe position may improve over the course of a number of months. Trying to suture or reposition the globe surgical is not successful inmost cases. The aim of any salvaged globe is to be free of any discomfort and cosmetically acceptable to the owner.. v Regulars I Ophthalmology Column