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compare the postoperative refractive error among dogs implanted with 3 types of IOLs using streak retinoscopy. An additional aim of the study was to evaluate the reliability of the Binkhorst and Retzlaff theoretical IOL power formulas and compare their

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in Journal of the American Veterinary Medical Association

Several tools have been developed to aid in the performance of ophthalmic examinations. Streak retinoscopy has not changed since its inception in the 19th century 1 and is often used in horses. 2–6 , a,b However, few attempts have been made to

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in American Journal of Veterinary Research

Retinoscopy is an objective technique used to measure the refractive state of an eye. To better understand the optical factors that affect visual acuity, the refractive states of many species have been determined. 1–21 The technique has been used

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in American Journal of Veterinary Research

streak retinoscopy before and after IOL implant insertion. Streak retinoscopy was performed by use of a streak retinoscope g and a skiascopy rack h equipped with 16-mm lenses (range, −0.5 to +15 D; working distance, 67 cm). 7,18 For each eye

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in American Journal of Veterinary Research

many dogs lived in another state or country. Dogs that underwent postsurgical evaluations underwent streak retinoscopy in a standing position without pharmacologically induced mydriasis. Vertical meridians were evaluated by use of a retinoscope p in

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in American Journal of Veterinary Research

use of streak retinoscopy. Prior to retinoscopic examination, dogs received 1 drop of 1% cyclopentolate c or 1% tropicamide d in each eye. Although cyclopentolate is a more effective cycloplegic, values for refractive errors in human eyes do not

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in American Journal of Veterinary Research

ophthalmology practice in El Cerrito, Calif, between May 1, 2004, and March 31, 2006; all dogs but 1 were evaluated before the end of July 2005. Examination included streak retinoscopy, gonioscopy, indirect ophthalmoscopy, slit-lamp biomicroscopy, and A-scan, B

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To follow the development of the refractive error in the eyes of ostrich chicks from age 0 to day 37 after hatching.

Animals—35 ostrich chicks.

Procedures—Spot retinoscopy was conducted to assess refractive error in ostrich chicks. Seventy eyes of 35 ostrich chicks were examined. Of these, 18 chicks were followed over time. At least 4 serial measurements (at 2- to 7- day intervals) were conducted in each of these chicks from day 1 to 37 after hatching. Seventeen additional chicks were examined on days 0, 3, 12, and 19 after hatching.

Results—Ostrich chicks were myopic at hatching, with a mean ± SD refractive error of −4.47 ± 0.15 diopters (D). The refractive error rapidly decreased during the first week of life, and by day 7 after hatching, chicks were slightly hyperopic, with a mean refractive error of 0.42 ± 0.12 D. After day 7, there were no significant differences in the mean refractive error.

Conclusions—The development of optics in the ostrich eye appears to be unique among animals and is characterized by myopia at hatching, rapid onset of emmetropia, and minimal variation in refractive error among chicks. (Am J Vet Res 2001;62:812–815)

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in American Journal of Veterinary Research

Abstract

Objective—To characterize the clinical and morphologic aspects of aqueous humor misdirection syndrome (AHMS) in cats and provide a hypothesis regarding its pathogenesis on the basis of detailed analysis of affected cats.

Design—Retrospective study.

Animals—32 cats (40 eyes).

Procedure—Medical records of cats in which AHMS was diagnosed from July 1997 to August 2003 were reviewed. In certain cats, results of additional diagnostic testing were also obtained, including A-scan, B-scan, and high-resolution ultrasonography; streak retinoscopy; video keratometry; and infrared neutralizing videoretinoscopy as well as results of analysis of flash-frozen sections and histologic examination of enucleated globes.

Results—Cats had a uniformly shallow anterior chamber, intact lens zonules, and a narrowed approach to an open iridocorneal angle. Mean age of affected cats was 11.7 years (range, 4 to 16 years), and female cats were significantly more often affected than male cats. Clinical signs included mydriasis, decreased pupillary light reflex, decreased menace response, and blindness. Glaucomatous changes to the optic nerve, incipient cataracts, and eventual blindness were seen. Intraocular pressure was ≥ 20 mm Hg (range, 12 to 58 mm Hg) in 32 of 40 eyes. Ultrasonography and histologic examination revealed a thickened anterior vitreal face interposed between the lens and ciliary body, partial ciliary cleft collapse, and cavitated vitreal regions. Various treatment modalities were used.

Conclusions and Clinical Relevance—AHMS affects older cats, especially females, and may result in glaucoma, vision loss, and signs of ocular pain. Topical administration of carbonic anhydrase inhibitors decreased intraocular pressure. (J Am Vet Med Assoc 2005;227:1434–1441)

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To measure postoperative anterior chamber depth (ACD), corneal curvature, and refractive state of feline eyes after lens removal and implantation of a prosthetic intraocular lens (IOL) and determine appropriate IOL use in cats.

Animals

8 clinically normal adult cats.

Procedure

A-scan ultrasonic biometry, keratometry, and streak retinoscopy were performed on both eyes of each cat before and after lens removal and implantation of a prosthetic IOL. Three diopter (D) IOL strengths were used: 48, 51, and 60 D. Measurements were recorded for 12 weeks after surgery.

Results

IOL were well tolerated by cats, with no serious complications attributable to implantation or presence of the IOL. The ACD was significantly greater after (8.30 mm) than before (4.97 mm) surgery; however, it became slightly more shallow during the 4 weeks after surgery, suggesting that the IOL shifted anteriorly in the eye. Significant difference in corneal curvature was not detected before or after surgery among eyes with various IOL. Twelve weeks after surgery, eyes with 48-, 51-, and 60-D IOL had mean ± SD refractive state of +2.1 ± 0.49, +0.42 ± 0.20, and -2.6 ± 0.78 D, respectively. Linear regression analysis of refractive state on IOL power for all eyes at 12 weeks after surgery predicted that +52.8-D IOL was necessary to best approximate emmetropia in these cats.

Conclusion and Clinical Relevance

IOL of substantially higher diopter strength than that needed in dogs was required to achieve emmetropia after lens extraction in cats. A 52- to 53-D IOL is required to correct feline eyes to near emmetropia after lens removal. (Am J Vet Res 1998;59:1339–1343)

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in American Journal of Veterinary Research