Surgery for lens instability

Traction suture fixation technique using a capsular tension ring fragment for severe lens displacement during cataract surgery in dogs

OBJECTIVES

To describe the traction suture fixation technique for severely displaced lenses (≥180°) using a capsular tension ring (CTR) fragment during cataract surgery in dogs, and to retrospectively investigate its clinical outcomes.

ANIMALS STUDIED

Eight dogs (nine eyes).

PROCEDURES

The medical records of dogs with severe lens displacement (≥180°) due to cataracts that underwent traction suture fixation during cataract surgery using a CTR fragment at the Grand Animal Hospital (Hyogo, Japan) between November 2019 and September 2022 were retrospectively reviewed. The retrieved data included the signalment, type of CTR, and postoperative outcomes.

RESULTS

A single CTR fragment was used to fix the capsular bag to the sclera in six eyes, and two CTR fragments were used at two sites in three eyes. The lengths of the CTR fragments used were 1 one-fifth fragment, 3 one-fourth fragments, and 8 one-third fragments. Postoperative complications included uveitis (nine eyes), glaucoma (one eye), posterior iris adhesion (one eye), corneal ulcer (one eye), and intracorneal stromal hemorrhage (one eye). Vision was maintained in all dogs during the follow-up period (2 months to 2 years and 8 months) without recurrent capsular bag displacement.

CONCLUSIONS

This technique can correct and stabilize capsular bag displacement relatively easily through a small incision during cataract surgery in dogs with severe lens displacement. Intraocular lens implantation was also possible.

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.

Posterior lens capsule rupture in non-diabetic canine cataracts: Pre-operative, intra-operative, and post-operative findings

PURPOSE

To describe clinical features of non-diabetic canine cataracts with presumed pre-existing posterior capsule rupture (PLCR) and their surgical outcomes.

METHODS

Clinical records of 497 non-diabetic canines that underwent elective cataract surgery were reviewed. Twelve canines met the inclusion criteria indicative of PLCR pre-dating surgery.

RESULTS

The incidence of presumed pre-existing PLCR was 12/497 (2.4%). Cataracts included were unilateral in 10 out of 12 canines (83.3%) and bilateral in the remaining two (16.7%). Four eyes (28.6%) had clinically detectable pre-operative lens-induced uveitis. The mean age at cataract diagnosis for cases included was 6.6 years, and golden retrievers were the most common breed affected (28.6%). Phacoemulsification surgery was performed at a median time of 110 days (range 17-403 days) after presentation. Pre-existing PLCR was found intra-operatively as a large ellipse spanning the posterior capsule from equator to equator centrally in 12 eyes and peripherally in two eyes. The capsular defect in all eyes with PLCR incorporated a distinct "pseudo-capsule" preventing vitreal presentation and ruling out intraoperative surgeon rupture. Ten eyes (71.4%) received an intraocular lens implant (IOL), and 13 eyes (92.9%) maintained vision throughout a mean follow-up period of 12 months.

CONCLUSION

Posterior lens capsule rupture of blunt trauma origin and associated cataract formation, as reported in humans, may also be an infrequent but distinct cause of some cases of non-diabetic canine cataracts. Medical management of phacolytic uveitis and delayed phacoemulsification surgery may be beneficial by allowing time for "pseudo-capsule" development, increasing the likelihood of IOL placement and improved visual outcomes.

Acute Blindness

Sudden loss of vision is an ophthalmic emergency with numerous possible causes. Abnormalities may occur at any point within the complex vision pathway, from retina to optic nerve to the visual center in the occipital lobe. This article reviews specific prechiasm (retina and optic nerve) and cerebral cortical diseases that lead to acute blindness. Information regarding specific etiologies, pathophysiology, diagnosis, treatment, and prognosis for vision is discussed.

Inheritance of cataracts and primary lens luxation in Jack Russell Terriers

OBJECTIVE

To characterize heritability and mode of inheritance of cataracts and primary lens luxation in Jack Russell Terriers.

ANIMALS

872 Jack Russell Terriers from which buccal epithelial cells were collected and phenotypes for cataracts and lens luxation were determined and an additional 1,898 Jack Russell Terriers without phenotypic information used to complete pedigree relationships and that were included in the analyses.

PROCEDURES

Narrow-sense heritabilities and genetic correlation for cataracts and lens luxation were modeled by use of threshold analysis, whereas complex segregation analysis was used to characterize mode of inheritance. For the analyses, dogs < 6 years old, unless confirmed as having cataracts or lens luxation, were classified as an unknown phenotype. The possible involvement of an HSF4 mutation in cataracts was determined by DNA sequencing.

RESULTS

Cataracts and primary lens luxation were highly heritable and genetically correlated, and neither was controlled by a single gene. Cataracts were not associated with an HSF4 mutation.

CONCLUSIONS AND CLINICAL RELEVANCE

Analysis of the data indicated that concerted selection against both cataracts and primary lens luxation when choosing breeding animals can be used to improve ocular health in Jack Russell Terriers.

A modified ab externo approach for suture fixation of an intraocular lens implant in the dog

The goals of canine cataract and lens instability surgery should be to ensure a small incision, minimal tissue trauma, shortened surgical time, maintenance of the anterior chamber, and restoration of emmetropia through the use of a stable intraocular lens specifically designed for the canine eye. While this is usually the case with routine phacoemulsification and in-the-bag intraocular lens implantation, it is often not the case with lens instability, lens luxation or large posterior capsular ruptures. In such cases the incisions are often larger, surgical time and tissue trauma are excessive, and the patient is often left aphakic. The goal of this paper is to present a modified ab externo technique designed to allow removal of the lens and placement of a ciliary sulcus sutured IOL through a small incision, with minimal trauma and shortened surgical time. Use of this technique may allow more canine patients to be emmetropic postoperatively. In addition, the ease of this procedure may encourage earlier removal of an unstable lens and decrease the risk of secondary glaucoma and retinal detachment that occur in association with lens luxation.

Outcomes of nonsurgical management and efficacy of demecarium bromide treatment for primary lens instability in dogs: 34 cases (1990-2004)

OBJECTIVE

To determine outcome of initial conservative management for primary lens luxation and evaluate topically administered demecarium bromide miotic treatment for prevention of anterior lens luxation, glaucoma, and vision loss in dogs.

DESIGN

Retrospective case series.

ANIMALS

34 dogs with primary lens luxation.

PROCEDURES

Medical records of affected dogs were reviewed for times to anterior luxation, luxation of the lens in the opposite eye, development of glaucoma, and vision loss.

RESULTS

At 4 to 6 weeks and at 3 months after diagnosis of lens instability (subluxation or posterior luxation), 100% (34/34 and 29/29, respectively) of conservatively managed eyes retained vision. At 1 year after diagnosis of lens instability, 80% (16/20) of conservatively managed eyes retained vision, and at 2 years after diagnosis of lens instability, 11 of 19 conservatively treated eyes retained vision. The only significant effect of miotic treatment was to delay anterior lens luxation in eyes with lens instability. Miotic treatment did not significantly affect the time from anterior lens luxation in 1 eye to anterior luxation in the other eye, time to onset of glaucoma, or time to loss of vision in eyes with an unstable lens.

CONCLUSIONS AND CLINICAL RELEVANCE

Prophylactic topically administered miotic treatment may be effective at delaying anterior luxation of an unstable lens in eyes affected by primary lens instability. Conservative medical management of dogs with primary lens instability is a reasonable alternative to surgical removal of a subluxated or posteriorly luxated lens via intracapsular lens extraction.

Canine cataracts, diabetes mellitus and spontaneous lens capsule rupture: a retrospective study of 18 dogs

OBJECTIVE

To describe the clinical presentation and surgical outcome of diabetic canine patients with cataracts and preoperative spontaneous lens capsule rupture.

ANIMALS STUDIED

A total of 20 dogs and 40 eyes were included in the retrospective evaluation. The patients' ages ranged from 5 to 14 years (mean 8.5 years).

RESULTS

All dogs had clinical diabetes mellitus, with the duration since diagnosis ranging from 30 to 240 days (mean 123 days). Cataracts were bilateral and noted to have been present for 14-112 days (mean 39 days). Of the 40 eyes affected with cataracts, 30 had a spontaneous rupture of the lens capsule prior to surgery. The capsular rupture was diagnosed on clinical examination in 28/30 eyes and was noted intraoperatively in 2/30. The location of the capsular rupture was equatorial in 29/30 and posterior in 1/30 eyes. Surgery was performed in 38/40 eyes, with one case lost to follow-up without surgical intervention. Prior to surgery, routine diagnostic ophthalmic examination, ocular ultrasound, electroretinography, and systemic evaluation were performed in all dogs. Surgical procedures included phacoemulsification in 28/40 eyes, with IOL placement performed in 20/28 eyes. Intrascleral prosthesis placement or enucleation was performed in 8/40 and 2/40 eyes, respectively, due to a significantly reduced ERG or secondary glaucoma.

CONCLUSIONS

The duration of clinical follow-up (19/20 dogs) ranged from 1 to 36 months (mean 12.9 months). All eyes that had cataract surgery with or without IOL placement were sighted at the time of the last follow-up examination. Spontaneous lens capsule rupture associated with diabetes mellitus, cataract and rapid lens intumescence occurs in the dog. Early surgical intervention, prior to secondary complications of glaucoma and loss of retinal function, is associated with a favorable outcome.

The use of transscleral cyclophotocoagulation with a diode laser for the treatment of glaucoma occurring post intracapsular extraction of displaced lenses: a retrospective study of 15 dogs (1995-2000)

The objective of this retrospective study was to evaluate transscleral cyclophotocoagulation (TSCP) using a diode laser for treating aphakic glaucoma that developed after intracapsular lens extraction (ICLE) had been performed for displaced lenses. Records of 15 dogs (21 eyes) were reviewed. The intraocular pressure (IOP) and the presence of vision were recorded at the time of ICLE and TSCP and at 1, 3, 6-9, 12 and 24 months post TSCP. The glaucoma was considered controlled if the IOP was less than 25 mmHg. The results indicated that the effectiveness of TSCP using a diode laser for treating aphakic glaucoma was of a short-term duration (1-3 months), with three patients needing repeat TSPC. In addition, adjunctive antiglaucoma medications were often required to maintain an adequately controlled IOP. Over the 24-month period the number of dogs requiring intrascleral prosthesis, intraocular gentamicin or enucleation, or that were lost to follow-up, increased.