Evaluation of 30- and 25-diopter intraocular lens implants in equine eyes after surgical extraction of the lens.
OBJECTIVE
To determine appropriate intraocular lens (IOL) implant strength to approximate emmetropia in horses.


METHODS
16 enucleated globes and 4 adult horses.


METHODS
Lens diameter of 10 enucleated globes was measured. Results were used to determine the appropriate-sized IOL implant for insertion in 6 enucleated globes and 4 eyes of adult horses. Streak retinoscopy and ocular ultrasonography were performed before and after insertion of 30-diopter (D) IOL implants (enucleated globes) and insertion of 25-D IOL implants (adult horses).


RESULTS
In enucleated globes, mean +/- SD lens diameter was 20.14 +/- 0.75 mm. Preoperative and postoperative refractive state of enucleated globes with 30-D IOL implants was -0.46 +/- 1.03 D and -2.47 +/- 1.03 D, respectively; preoperative and postoperative difference in refraction was 2.96 +/- 0.84 D. Preoperative anterior chamber (AC) depth, crystalline lens thickness (CLT), and axial globe length (AxL) were 712 +/- 0.82 mm, 11.32 +/- 0.81 mm, and 40.52 +/- 1.26 mm, respectively; postoperative AC depth was 10.76 +/- 1.16 mm. Mean ratio of preoperative to postoperative AC depth was 0.68. In eyes receiving 25-D IOL implants, preoperative and postoperative mean refractive error was 0.08 +/- 0.68 D and -3.94 +/- 1.88 D, respectively. Preoperative AC depth, CLT, and AxL were 6.36 +/- 0.22 mm, 10.92 +/- 1.92 mm, and 38.64 +/- 2.59 mm, respectively. Postoperative AC depth was 8.99 +/- 1.68 mm. Mean ratio of preoperative to postoperative AC depth was 0.73.


CONCLUSIONS
Insertion of 30-D (enucleated globes) and 25-D IOL implants (adult horses) resulted in overcorrection of refractive error.
McMullen
Richard J
RJ
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
Davidson
Michael G
MG
Campbell
Nigel B
NB
Salmon
Jacklyn H
JH
Gilger
Brian C
BC
D000818:Animals; D000867:Anterior Chamber / Q000601:surgery; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use; D037901:Euthanasia, Animal; D015353:Eye Enucleation / Q000379:methods / Q000662:veterinary; D006734:Horse Diseases / Q000601:surgery*; D006736:Horses; D019654:Lens Implantation, Intraocular / Q000379:methods / Q000662:veterinary*; D007908:Lens, Crystalline / Q000033:anatomy & histology / Q000601:surgery*; D007910:Lenses, Intraocular / Q000662:veterinary*; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000628:therapy / Q000662:veterinary*; D054140:Refractive Surgical Procedures / Q000379:methods / Q000662:veterinary*
D000900:Anti-Bacterial Agents