Trans-corneal reduction of anterior lens luxation in dogs with lens instability: a retrospective study of 19 dogs (2010-2013)

An evaluation of intracapsular lens extraction and transcorneal lens reduction for treatment of anterior lens luxation in dogs

OBJECTIVE

The aim of the study was to evaluate success rate, complications, and outcomes in dogs with anterior lens luxation (ALL) treated with intracapsular lens extraction (ICLE) or transcorneal lens reduction (TCLR).

PROCEDURE

Medical records of dogs with ALL undergoing ICLE or TCLR from 2014 to 2021 were reviewed. Signalment, presenting complaint, history, ophthalmic examination findings, short-term complications, and outcomes were analyzed.

RESULTS

There were 20 ICLEs and 31 TCLRs; however, some cases were included in both groups. One ICLE was unsuccessful and four had undergone TCLR first, leaving 15 ICLEs. Three TCLRs were unsuccessful, four were lost to follow up, and three subsequently underwent ICLE due to recurrent ALL, leaving 21 TCLRs. Anterior uveitis was more common following ICLE than TCLR, p < .001 The frequencies of other short-term complications (post-operative hypertension and corneal ulceration) were not statistically different between groups. Median follow-up was 256 and 48 days for ICLE and TCLR, respectively. Vision was retained in 7/10 (70%) eyes following ICLE and 4/9 (44%) eyes following TCLR, p = .34. Enucleation was recommended for fewer eyes following ICLE (2/15 [13%]) than TCLR (7/21 [33%], p = .47). In total, lens extraction was achieved in 19/20 (95%) ICLEs and lens reduction was achieved in 28/31 (90%) TCLRs. Anterior lens luxation recurred in 10/24 (41%) TCLRs.

CONCLUSIONS

The present study adds data to the current knowledge base regarding the treatment of ALL in dogs and highlights the need for future prospective studies containing a larger number of animals to help inform treatment decisions for dogs with ALL.

Sulcus intraocular lens implantation in 17 dogs using a modified ab externo technique

OBJECTIVE

To describe a modified ab externo method of sulcus intraocular lens (IOL) fixation and report outcomes of eyes treated with this approach.

PROCEDURES

Records of patients with lens instability or luxation that underwent a lensectomy and sulcus IOL implantation from January 2004 to December 2020 were reviewed.

RESULTS

Nineteen eyes of 17 dogs had a sulcus IOL placed via a modified ab externo approach. The median follow-up time was 546 days (range 29-3387 days). Eight eyes (42.1%) developed POH. A total of six eyes (31.6%) developed glaucoma and required medical management long term to control IOP. The IOL position was satisfactory in most cases. Nine eyes developed superficial corneal ulcers within 4 weeks following surgery, all of which healed without complication. At the time of the last follow-up, 17 eyes were visual (89.5%).

CONCLUSIONS

The technique described represents a potentially less technically challenging option for sulcus IOL implantation. The success rate and complications are similar to previously described approaches.

Comparative effects of latanoprost and latanoprostene bunod on intraocular pressure and pupil size in ophthalmologically normal Beagle dogs

OBJECTIVE

To compare effects of latanoprost, a topical prostaglandin analogue (PGA) commonly used to treat glaucoma and lens instability in dogs, and latanoprostene bunod, a novel PGA with a nitric oxide-donating moiety, on intraocular pressure (IOP) and pupil diameter (PD).

ANIMALS STUDIED

Ten ophthalmologically normal Beagle dogs.

PROCEDURES

Dogs were treated twice a day for 5 days in a randomly selected eye with either latanoprost or latanoprostene bunod. After a 6-week washout period, dogs were treated with the opposite drug. IOP and PD were measured at treatment times, at midday on days 1 and 5, and for 6 days post-treatment.

RESULTS

Both drugs significantly decreased IOP and PD. At midday on day 5 of treatment, mean IOP in eyes treated with latanoprost was 4.5 mmHg lower than the fellow eye and 3.0 mmHg lower than the same eye at baseline, while mean IOP in eyes treated with latanoprostene bunod was 5.5 mmHg lower than the fellow eye and 3.6 mmHg lower than baseline. Mean PD was 0.94 mm in eyes treated with latanoprost and 0.76 mmHg in eyes treated with latanoprostene bunod. There was no significant difference between the two drugs for either parameter at that time point (p = .372 and .619, respectively, for IOP relative to control and to baseline; p = .076 for PD) or when analyzed longitudinally. Significant diurnal variation in PD was noted and may have implications for treatment of lens' instability.

CONCLUSIONS

Latanoprost and latanoprostene bunod produce similar IOP reduction and miosis in normal canine eyes.

Ocular Emergencies in Small Animal Patients

Small animal ocular emergencies vary from relatively benign to potentially vision or life threatening, with significant overlap in clinical signs. Careful ophthalmic examination in dim light conditions with a bright light source and competent patient head restraint are crucial to properly diagnosing ocular disease. Adjunctive ophthalmic diagnostic testing should be performed to rule out corneal ulceration, glaucoma, and dry eye before empiric topical antibiotic or steroid medications are prescribed. Most emergency cases present because of ocular redness, cloudiness, discomfort, apparent bulging, or vision loss; categorizing differential diagnoses on this basis can be helpful to the emergency clinician.

Lens-Related Emergencies: Not Always So Clear

Emergencies involving the crystalline lens are not common; however, their clinical signs must be recognized quickly to begin treatment or referred immediately to improve the chances of retaining sight. The lens is a unique structure because of its immunologically privileged status and its imperative clarity for vision. Any insult to the lens capsule's integrity, its position within the globe, or to its clarity may result in undesirable sequelae.