Trans-corneal reduction of anterior lens luxation in dogs with lens instability: a retrospective study of 19 dogs (2010–2013) Keith W. Montgomery,* Amber L. Labelle† and Anne J. Gemensky-Metzler‡ *Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, 1052 William Moore Drive, Raleigh, NC 27607, USA; †Department of Veterinary Clinical Medicine, University of Illinois Urbana-Champaign, 1008 W. Hazelwood Drive, Urbana, IL 61802, USA; and ‡Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA Address communications to: Keith W. Montgomery Tel.: +1-919-513-6659 Fax: +1-919-513-6711 e-mail: keith_montgomery@ ncsu.edu Abstract Objective To evaluate the success rate and outcome of trans-corneal reduction of ante- rior lens luxation (TR-ALL) in dogs with lens instability. Animals Studied Nineteen dogs with anterior lens luxation. Procedures Medical records of dogs with anterior lens luxation (ALL) were reviewed: dogs were included if TR-ALL was performed followed by medical therapy in the form of topical 0.005% latanoprost ophthalmic solution. The duration of ALL, vision status, ophthalmic examination abnormalities, reason for performing TR-ALL and details of TR-ALL were recorded. Success rate for TR-ALL as well as postprocedure complications were also assessed. Results Twenty eyes from 19 dogs met the inclusion criteria. Median age was 6.5 years (0.3–15 years) and 47% were terriers (9/19). Successful TR-ALL was achieved in 85% of eyes (17/20); failure was attributed to posterior synechia or vitreous expansion. Short-term complications included corneal ulceration (2/20) and anterior uveitis (3/20); recurrence of anterior luxation occurred in only one dog. Median follow-up for visual eyes (11) following successful TR-ALL was 353 days (range of 1 to 1182 days). Vision was retained in 54.5% (6/11) of eyes with a median time to vision loss of 12 months as a result of glaucoma or presumed retinal detachment. Conclusions Trans-corneal reduction of ALL provides a non-surgical alternative to intracapsular lens extraction (visual eyes) or enucleation (nonvisual eyes) in dogs. Long-term visual outcome of TR-ALL is comparable to intracapsular lens extraction for ALL. Key Words: anterior lens luxation, canine, couching, lens instability, nontraumatic, trans-corneal reduction INTRODUCTION Etiologies for anterior lens luxation (ALL) in the dog include congenital, primary, and secondary. 1,2 Congenital lens luxation is a rare form of lens instability caused by absence of zonular fibers attaching to the lens equator. 3 Primary lens luxation involves an inherited zonular defect that results in lens instability manifesting at 3–6 years of age; predilection for the terrier breeds, Tibetan Terrier, and Shar Pei has been reported. 1–9 A mutation in the ADAMTS17 gene has been associated with primary lens luxation in Miniature Bull Terriers, Lancashire Heelers, and Jack Russell Terriers as well as 14 additional breeds of terrier ancestry. 10,11 Causes of secondary lens luxation are more numerous and include uveitis, hypermature cata- racts, trauma, senescence, and glaucoma. 12 Common sequelae to lens instability, irrespective of lens location, include glaucoma, retinal detachment, hyphema, and vision loss. Anterior lens luxation is frequently a sur- gical emergency due to pupillary block glaucoma. Reported surgical techniques for lens extraction include intracapsular lens extraction (ICLE) for ALL as well as two-handed phacoemulsification (with or without removal of the lens capsular bag) and/or capsular tension rings for mild to severe lens instability. 13 Ciliary sulcus lens implan- tation, endoscopic laser cycloablation, and prophylactic © 2014 American College of Veterinary Ophthalmologists Veterinary Ophthalmology (2014) 1–5 DOI:10.1111/vop.12142