Third eyelid laceration in a cat

Patient presentation

Outdoor, male neutered, 3 year old, Domestic Shorthair cat from a multi-cat household presented on the evening of the 23 September 2023 with mucopurulent ocular discharge and head-shy behaviour with sneezing. The onset was very sudden. A brown discolouration was present on the medial third eyelid at the site of cartilage location. This was suspected to be a foreign body. There were no corneal lacerations seen, but significant conjunctival oedema and lateral lower lid entropion was present, which was unusual for his good conformation (Figure 1). The entropion was believed to be spastic or cicatricial, in response to ocular pain, as is typical of secondary entropion (Estrada Araya et al, 2024).

The eye area was cleaned with Ocryl because of its soothing, antiseptic and disinfectant properties (TVM, 2019). A minor scratch wound to the left nostril was found, and the patient was sedated with Domitor (medetomidine hydrochloride) 0.04 mg/kg intramuscularly and ketamine 4 mg/kg IM for thorough examination. With further examination, the brown mark on the third eyelid was discovered to be necrotic tissue with full thickness crescent-shaped laceration through the third eyelid, exposing the cartilage on the inner surface. A further laceration at the lateral margin of the third eyelid gland was discovered. On staining the cornea it was found to be fluorescein negative.

The registered veterinary nurse (RVN) on duty consulted the veterinary surgeon who agreed a surgical repair would be required. Because of the clinic's location, instruction was given on how to perform this and the RVN completed the procedure as described by the veterinary surgeon with a cruciate suture pattern to oppose edges of both lacerations (Figure 2). Ocular surgery would normally be performed using magnification for higher visualisation of the intricate surfaces; however, as this was not available and the veterinary surgeon deemed the case requiring immediate intervention when transport off-island was not possible, the RVN proceeded under instruction. The patient was already under sedation and surgery commenced with the patient anaesthetised with isoflurane 1% via mask. No ocular speculum was present so a stay suture was used to reveal lower conjunctiva and expose the third eyelid during surgery using 3-0 PDS and anchor point ventrolateral zygomatic arch (Gelatt et al, 2021). The ocular surface was cleaned with 10% povidone-iodine solution diluted to 0.5% (1:20) indicated for ocular surfaces. This dilution provides rapid broad spectrum antimicrobial action without corneal epithelial oedema, corneal epithelial sloughing, eyelid oedema or conjunctival irritations associated with stronger povidone iodine, chlorhexidine or alcohol-based solutions (Gelatt et al, 2021). The lateral margin wound was found unsuitable for closure using a cruciate pattern, as this caused inrolling and mismatch of the margin edge, so two interrupted sutures of 5-0 Vicryl were used to fully oppose wound edges. Vicryl 5-0 is recommended for conjunctival suturing as a result of the long absorption time with minimal knots exposed to the corneal surface to prevent irritation (Demir and Altundağ, 2020). After surgical debridement of the necrotic tissue, two cruciate sutures were used on medial full thickness laceration: one horizontally at the ventral wound edge, and one vertically at the dorsal edge to reduce folding of the margin. All sutures were placed superficially and at partial thickness to avoid corneal irritation. During surgery, corneal irrigation using 0.9% saline could have been used, as this helps to reduce corneal irritation, drying and abrasion common during anaesthesia (Gelatt et al, 2021), although was not necessary during this procedure as the surgery time was short.

Isathal (Dechra) was prescribed 5 times daily to provide lubrication and prevention of infection. While Isathal is usually administered twice daily according to license, the patient was difficult to apply drops to, and the concurrent use of a lubricant product, in the event of a missed or delayed application of subsequent Isathal would be detrimental to the patient. A non-steroidal anti-inflammatory drug (Metacam 0.2 mg/kg subcutaneously) was started intra-operatively and continued orally at home once daily. An antibiotic (Convenia, Zoetis, 8 mg/kg subcutaneously) was given intra-operatively as the patient would be difficult to tablet. This was given as the wound showed existing necrosis, and eye surgeries are always classed as contaminated because of their nature (Gelatt et al, 2021), with Staphylococcus, Streptococcus, and Pseudomonas species the most common bacteria associated with canine and feline corneal stromal ulcerations (Verdenius et al, 2024). In another study, conjunctival cultures in healthy cats were positive in 8.5% of cases for either Serratia marcescens or Cutibacterium acnes prior to intraocular surgery (Coall et al, 2022).

During surgery two further small wounds were found, one at the right pinna proximal rostral edge in the form of a shallow laceration and the other at the left cranial temporal region rostral to the pinna. These were both clipped and cleaned with 2% chlorhexidine. Care was taken to avoid contact with ocular surfaces because of the corneal epithiliotoxic properties of chlorhexidine (Gelatt et al, 2021) but was used because of its bacteriostatic, bacteriocidal, fungistatic, fungicidal and virucidal properties (Horaitou, 2022). The cranial wound was also flushed as some purulent discharge was present. The patient was then hospitalised for 2 days for re-examination, regular ophthalmic lubrication because of reduced tear production post-ketamine administration, and to avoid other cat interference in a multi-cat household and to enforce Elizabethan collar use to prevent self-trauma (Gelatt et al, 2021).

The day after surgery the eye was comfortable, with a small amount of serous discharge, which was cleaned with Ocryl. Isathal was applied five times daily with no discomfort but some bouts of intense sneezing, often after application of Isathal. Metacam oral was well accepted in food.

Two days post-surgery (Figure 3) it was noted that slight shelving was present at the lateral lower lid, but ocular build-up was present laterally and at the medial canthus. This was regularly cleaned with Ocryl, and Isathal applications were much more comfortable. The sutures were checked on examination and found to be in situ, holding well and with no visible irritation on the underside of conjunctiva. Necrosis did not appear to have spread at this time. The cranial wound was still producing a purulent discharge.

Three days post surgery (Figure 4), the transient lower lid shelving had resolved, there was minor ocular discharge present, and the corneal surface was found to be fluorescein positive across a third of the corneal surface aligned with lateral suture placement, with a minor inrolling of the suture at this margin edge. The cranial wound was no longer producing a purulent discharge. Sneezing almost resolved other than occasionally after Isathal application, with the patient tolerating Isathal well, although he was rubbing at the eye in the morning.

Four days post-surgery, the corneal ulceration had developed no change, the cranial wound scab was removed and gave no further discharge. The patient seemed comfortable and was tolerating Isathal better. After clinical discussion it was agreed to maintain current medications with a plan to remove the lateral margin suture at 8 days post-surgery to reduce further corneal ulceration, unless further decline was seen before then. The other sutures were to remain in situ longer depending on the degree of adherence.

Five days post-surgery (Figure 5), the patient was experiencing frustration with kennelling and increased effort was made to give lots of exercise and mental stimulation. This was provided through interaction, toys and a grooming session. Almost no ocular discharge or periocular swelling was present and the patient no longer required daily eye cleans with Ocryl.

Six days postoperatively the patient had no change in condition and was doing well. He displayed intermittent signs of stress from the kennel environment, but was given increased grooming sessions and time supervised outside the kennels to counteract this.

Seven days postoperatively the patient condition had not changed. Corneal fluorescein was found to be considerably smaller than previously seen, and a plan was made for him to go home the following day providing no decline in condition was noted.

Eight days postoperatively the patient was discharged and advised to continue Isathal. It was discussed that he may require sedation to remove the sutures, but distress in the clinic was deemed unacceptable for his health.

Nine days postoperatively (Figure 6) there was a suspicion of a slight depression present in the ulcer, although a fluorescein check still showed an improvement and only superficial damage to the cornea. Had the ulcer deepened into a stromal ulcer, there would have been significant loss to the integrity and strength of the cornea and immediate surgical intervention by an ophthalmologist required. This is because at the stage of significant stromal loss indicated by a visible depression or fluorescein-negative centre to the ulcer, such as with descemetocele ulceration, corneal rupture may be imminent (Thomasy, 2020). Eleven days post-operatively the medial sutures were found to be no longer in situ, and the corneal ulcer still present although reduced in size. Fourteen days postoperatively the ulcer was found to be healed and fluorescein negative. The Isathal was to be continued for a further 48 hours although Metacam was to be stopped.

Following this, the patient was checked again at 20 days postoperatively and 30 days postoperatively. At both checks the cornea was fluorescein negative and no concerns were raised, the patient was signed off and it was deemed he had made a full recovery.

Discussion

On reflection, the patient may have benefited from anxiolytics to improve ease of administration of eye drops. This would have enabled the Isathal to have been applied twice daily as per the data sheet, and concurrent use of lubricant without concerns of increasingly difficult behaviours preventing the ocular medication administration.

Additionally, as the ulceration of the cornea appeared at 3 days post-surgery this is more likely caused by suture irritation than the initial wounds the patient presented with. At the time, as a result of the lack of magnification and the very superficial nature of the corneal damage, the veterinary surgeon did not deem it appropriate to remove the sutures prematurely. However, this was considered and, if the ulcer had deepened, would have been actioned. Alternatively, the patient could have benefited from a therapeutic soft contact lens placement either immediately post-surgery, given that surgery had been completed without magnification and therefore was likely less precise than if magnification had been present, or alternatively as soon as the corneal ulceration was identified.

Overall the case experienced no significant or unexpected complications and the patient healed well.

Conclusions

This case encompassed a minor surgical procedure underatken by an RVN under veterinary direction. As a result of the isolated rural island location of the clinic and the persistent long-term inclement weather conditions, the patient could not be airlifted off the island for more specialist intervention.

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