Safety study of capsular tension ring use in canine phacoemulsification and IOL implantation

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.

The association of topical flurbiprofen with the incidence of postoperative glaucoma after phacoemulsification in dogs

OBJECTIVE

To investigate the relationship between topical administration of flurbiprofen plus corticosteroids versus corticosteroids alone following phacoemulsification and the development of postoperative glaucoma in dogs.

ANIMAL STUDIED

Thirty-eight/eighty-three (45.8%) eyes were prescribed topical flurbiprofen plus corticosteroids immediately postop while 45/83 (54.2%) eyes received topical corticosteroids alone.

PROCEDURES

Logistic regression models were performed to analyze the relationship between topical flurbiprofen and development of glaucoma and to predict potential risk factors for postoperative glaucoma occurrence.

RESULTS

Eighty-three eyes (65 dogs) were included. The mean age at surgery was 8.2 years, with even gender distribution. Increasing age at the time of surgery significantly increased the probability of postoperative glaucoma occurrence (odds ratio [OR] = 1.344, 95% confidence interval [CI] 1.093-1.652; p = 0.005). Glaucoma occurred in 17/83 (20.5%) eyes; of these, 15/38 (39.5%) and 2/45 (4.4%) eyes were prescribed topical flurbiprofen plus corticosteroids and topical corticosteroids alone, respectively. Immediate postoperative use of topical flurbiprofen was significantly associated with an increased probability of postoperative glaucoma occurrence (OR = 19.183 [95% CI 3.367-109.286], p = 0.001).

CONCLUSIONS

Immediate postoperative use of topical flurbiprofen was a potential predisposing risk factor for the development of glaucoma following phacoemulsification. Restriction of postoperative use of topical flurbiprofen might decrease the possibility of postoperative glaucoma development in dogs.

Rotation of a toric intraocular lens with and without capsular tension ring: data from a multicenter non-inferiority randomized clinical trial (RCT)

BACKGROUND

Evaluation of clinical outcome in cohorts with versus without simultaneous implantation of a capsular tension ring (CTR) and a toric lens (Tecnis Toric). Main parameter was rotation referring - in contrast to misalignment - to the IOL axis change from immediately after implantation to the final postoperative position.

METHODS

Lens position was measured at baseline with the patient still in recumbent position, postoperative rotation was calculated by software. Postoperative evaluation included measurement three months after surgery or prior to an indicated revision surgery. Explorative re-evaluation of the underlying RCT's intent-to-treat population was performed for the entire sample and stratified for cohorts by 95% confidence intervals for binary endpoints' incidences (primary endpoint: absolute postoperative rotation ≤5 degrees; secondary endpoints: absolute deviation between achieved cylinder and target cylinder ≤0.5 dpt, postoperative corrected distance visual acuity (CDVA) ≥ 0.8). Data exploration was based on medians and quartiles.

SETTING

Outpatient study sites.

DESIGN

Re-evaluation based on data from a multicenter non-inferiority randomized clinical trial (RCT).

RESULTS

Sub cohorts (without CTR 89, with CTR 90 patients) did not present clinically relevant differences in preoperative characteristics: revision surgery was performed in 7 cases (3 without and 4 with CTR). Primary endpoint incidences for the total sample, without and with CTR were 90%/89%/90%; cylinder endpoint incidences were 46%/45%/46% and CDVA endpoint incidences 90%/92%/88%. Median absolute rotations were 1.74°/1.79°/1.72°, median absolute cylinder deviations 0.55/0.52/0.55 dpt and median visual acuity 1.0/1.0/1.0.

CONCLUSION

No clinically relevant differences between CTR subgroups were found; a satisfying three months rotational stability was achieved.

TRIAL REGISTRATION

The trial was registered retrospectively in the trial registry DRKS, trial registration number DRKS00015316 , date of registration 27. August 2018.

Calculation of posterior chamber intraocular lens (IOL) size and dioptric power for use in pet rabbits undergoing phacoemulsification

OBJECTIVES

To calculate the size and dioptric power of a posterior chamber intraocular lens (IOL) to achieve emmetropia in adult rabbits and to compare the dioptric power calculation results using a proprietary predictive formula to a retinoscopy-based method.

ANIMALS STUDIED

Three wild rabbit cadavers, seven pet rabbits with cataracts and ten healthy pet rabbits.

MATERIALS AND METHODS

Implant size was calculated using a capsular tension ring (CTR) (Acrivet^® , Berlin, Germany). Published and cadaveric biometric data were used in the predictive formula. An IOL power-escalation study compared the predicted values to the refraction results of one pet rabbit (P1) fitted with a + 41D canine IOL (Acrivet^® ) and six pet rabbits (P2-P7) fitted with prototype IOLs (Acrivet^® ). Retinoscopy of 10 healthy pet rabbits served as controls.

RESULTS

A 13.5 mm CTR fitted in all rabbits and permitted the use of a 13 mm IOL. The predicted IOL power ranged between +24D and +25D. The +41D IOL resulted in a refraction error of +8D. Progressive recalculation through a calibration formula led to the insertion of three +49D IOLs in two pet rabbits and a refraction of +6D to +8D, followed by seven +58D IOLs in four pet rabbits and a refraction median of 0D (range: -1.5D to +1D).

CONCLUSIONS

A 13 mm prototype IOL of +58D achieves emmetropia and is of adequate size for rabbits. The combined use of a CTR and retinoscopy is a useful method to calculate the size and refractive power of a new, species-specific, veterinary IOL.