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ABSTRACT: This study examined the captive western lowland gorilla (Gorilla gorilla gorilla) eye as compared and contrasted with the human eye. Bilateral ophthalmic examinations of western lowland gorillas (n = 5) while under general anesthesia were performed opportunistically, including slit-lamp biomicroscopy, dilated fundus examination, cycloplegic retinoscopy, Schiotz tonometry, corneal diameter and thickness measurements, A-scan and B-scan ultrasonography, keratometry, and cultures of the eyelid margins and bulbar conjunctiva. Mean spherical equivalent refractive error by cycloplegic retinoscopy was +1.20 +/- 0.59 diopters. Mean intraocular pressure by Schiotz tonometry was 12.0 +/- 4.3 mm Hg. Mean optic nerve head cup to disc ratio was 0.42 +/- 0.11. Mean horizontal corneal diameter was 13.4 +/- 0.8 mm, and mean vertical cornea diameter was 12.7 +/- 0.8 mm. Mean central corneal thickness by ultrasound pachymetry was 489 +/- 52 microm. Mean axial length of the eye by A-scan was 22.75 +/- 0.71 mm. Mean lens thickness by A-scan was 4.23 +/- 0.34 mm. Mean anterior chamber depth by A-scan was 4.00 +/- 0.26 mm. Mean keratometry reading was 44.38 +/- 1.64 diopters. Eyelid margin and bulbar conjunctival cultures isolated Candida sp. (n = 5), Staphylococcus aureus (n = 4), Staphylococcus epidermidis (n = 3), Staphylococcus saccharolyticus (n = 3), and Micrococcus sp. (n = 3). This study suggests important similarities between western lowland gorilla and human eyes. These similarities may allow diagnostics, techniques, and equipment for human eye surgery, such as those used for cataract extraction and intraocular lens implantation, to be successfully utilized for gorillas.
Journal of Zoo and Wildlife Medicine 10/2005; 36(3):430-3. · 0.38 Impact Factor
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ABSTRACT: To assess the safety and efficacy of hyperopic laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK).
Zale Lipshy University Hospital Laser Center for Vision, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Thirty-eight eyes of 25 patients were treated with LASIK for secondary hyperopia after RK using a Visx Star S2, S3, S4, or LADARVision excimer laser. Retreatment was done in 7 eyes. The main outcome measures were manifest refraction spherical equivalent (MRSE), uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), predictability of treatment, and complications.
Preoperative mean MRSE was +2.39 diopters (D) +/- 1.28 (SD) (range +0.87 to +6.00 D). At the last visit (25 eyes with minimum follow-up of 12 months, including retreatments), the mean follow-up was 23.3 +/- 7.3 months (range 12 to 34 months), the mean MRSE was +0.11 +/- 0.71 D, and the UCVA was 20/40 or better in 24 eyes (96%). Although no significant change in the mean MRSE was observed, the postoperative mean refractive cylinder showed a gradual increase over the follow-up period. No eye lost more than 2 lines of BSCVA.
Laser in situ keratomileusis was a safe and effective treatment with good predictability for the correction of consecutive hyperopia after RK. Cylindrical errors were difficult to correct, and astigmatic correction tended to regress over time. Retreatments are safe when old flaps were relifted.
Journal of Cataract [?] Refractive Surgery 09/2005; 31(8):1561-8. · 2.26 Impact Factor
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ABSTRACT: To compare the LADARVision (LV), Visx Star S3 (S3), and Visx Star S2 (S2) excimer lasers in the treatment of spherical hyperopia and hyperopic astigmatism with laser-assisted in situ keratomileusis.
A parallel, consecutive, three-surgeon, cohort comparison was performed at Zale Lipshy University Hospital, Laser Center for Vision, The University of Texas Southwestern Medical Center at Dallas, Texas for consecutive cases between January 2001 and October 2001.
Treatment outcomes of 105 hyperopic eyes with manifest refraction spherical equivalents of up to +6.50 diopters and astigmatism up to 3.75 diopters were compared. Forty-one eyes were treated with LV; 25 eyes were treated with S3; and 39 eyes were treated with S2. Outcome measures included uncorrected visual acuity, best spectacle-corrected visual acuity, predictability, and stability of treatments at 1 week and 1, 3, and 6 months.
All three lasers were comparable in terms of refractive stability and predictability. The LV group had consistently better uncorrected visual acuities than did the S2 and S3 groups during the follow-up period. At 6 months, the LV group had statistically significantly better visual results than the S3 group at the 20/25 and 20/20 levels, whereas the only significant difference between the LV and S2 groups was at the 20/25 level. Better visual outcomes were achieved with S2 than with S3, but the differences were not statistically significant. No eye lost more than one line of best spectacle-corrected visual acuity.
Predictability and stability of hyperopic laser-assisted in situ keratomileusis treatments with all three lasers were comparable. Visual results with LV at 6 months were statistically significantly better than those with S3 and S2.
Eye & Contact Lens Science & Clinical Practice 02/2004; 30(1):49-53. · 1.25 Impact Factor
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ABSTRACT: To compare visual outcomes with 2 commonly used excimer lasers, the Autonomous LADARVision (LV) (Alcon Laboratories Inc.) and the Visx Star S3 (S3), in the performance of myopic and hyperopic astigmatic laser in situ keratomileusis (LASIK).
Zale Lipshy University Hospital Laser Center for Vision, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
In this retrospective single-center 3-surgeon cohort comparison, 100 consecutive LV-treated myopic eyes with a mean manifest refraction spherical equivalent (MRSE) of -3.22 diopters (D) (range 0 to -6.00 D) (mean astigmatism 0.95 D [range 0 to 4.00 D]) were compared with 100 consecutive S3-treated eyes with a similar MRSE (mean MRSE -3.19 D; mean astigmatism 0.66 D [range 0 to 2.75 D]). Forty-one consecutive LV-treated hyperopic eyes with a mean MRSE of +2.59 D (range +1.00 to +6.00 D) (mean astigmatism 0.89 D [range 0 to 3.50 D]) were compared with 25 consecutive S3-treated eyes with a similar MRSE (mean MRSE +2.70 D; mean astigmatism 0.87 D [range 0 to 2.75 D]). The following outcomes were compared: uncorrected visual acuity, refractive predictability and stability, gain or loss of best spectacle-corrected visual acuity, and need for enhancement.
Statistically significant differences in outcomes were found between lasers in the treatment of hyperopia and hyperopic astigmatism. No outcome differences between lasers were found in the treatment of myopia and myopic astigmatism.
The LV and S3 lasers yielded equivalent results in myopic LASIK between 0 and -6.00 D; however, the LADARVision yielded statistically significantly better results in hyperopic LASIK between +1.00 and +6.00 D.
Journal of Cataract [?] Refractive Surgery 01/2004; 29(12):2351-7. · 2.26 Impact Factor
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ABSTRACT: To characterize patients with ocular surface drying and a diagnosis of keratoconjunctivitis sicca (KCS).
Patients with a prior diagnosis of KCS and symptoms of dryness or foreign-body sensation who also had vital staining of the interpalpebral fissure ocular surface in the absence of lid and ocular surface inflammation were entered into the study along with normal controls. Patients were segregated into those with "classic" KCS, who did not have concomitant meibomian gland dysfunction (MGD), and those with KCS and MGD. The latter had slit-lamp evidence of difficult-to-express or turbid meibomian secretions upon expression. Patients and normal controls were evaluated for tear volume, flow, and turnover using fluorophotometry; meibomian gland dropout by meibography; evaporation by evaporometry; and tear production by the Schirmer 1 test.
All patients with KCS had decreased tear volume, flow, and Schirmer 1 values as well as increased meibomian gland dropout. None of the patient groups were found to have increased tear evaporation compared with normals or other disease subgroups. No correlation between degree of meibomian gland dropout and evaporation was found. The degree of total vital staining or presence of corneal staining correlated with a more severe aqueous deficiency.
Patients with ocular surface drying in the absence of inflammation have decreased tear volume, flow, and Schirmer 1 values as well as increased meibomian gland dropout. The role of meibomian gland dropout or slit-lamp MGD in disease is unclear and in our study specifically did not correlate with increased tear evaporation.
Transactions of the American Ophthalmological Society 02/2003; 101:141-52; discussion 152-4.
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ABSTRACT: To evaluate and compare the surgically induced astigmatism in myopic eyes undergoing conventional and wavefront-guided LASIK.
A retrospective review was performed of the charts of 200 myopic eyes of 121 patients who underwent either custom or conventional treatments via the VISX S4 or LADARVision4000 platforms (50 consecutive eyes in each of the four groups). The primary outcome measure was manifest refraction, which was evaluated preoperatively and at 3 months postoperatively. The magnitude and axis of the unintended surgically induced astigmatism were calculated using vector analysis. The Student t test was used to compare the magnitudes of the surgically induced astigmatism and the absolute angle of error.
The mean preoperative manifest cylinder was 0.66 +/- 0.38 diopters (D) for conventional VISX S4 and 0.68 +/- 0.39 D for VISX CustomVue (P = .795), and 0.76 +/- 0.56 D for LADARVision and 0.61 +/- 0.36 D for LADAR CustomCornea (P = .114). The success index was 0.19 +/- 0.41 for VISX S4 and 0.49 +/- 0.49 for VISX CustomVue (P = .0013), and 0.25 +/- 0.47 for LADARVision and 0.20 +/- 0.39 for LADAR CustomCornea (P = .5721). The absolute mean angle of error was 4.4 +/- 13.9 degrees for VISX S4 versus 14.9 +/- 23.9 degrees for VISX CustomVue (P = .0085), and 6.1 +/- 12.30 for LADARVision versus 3.9 +/- 11.1 degrees for LADAR CustomCornea (P = .3501). Of the VISX CustomVue eyes, 32% had an absolute angle of error > 10 degrees, as compared to 10% for both the VISX S4 and LADAR CustomCornea eyes (P = .013), and 16% for the LADARVision group (P = .056).
Wavefront-guided ablation is associated with higher surgically induced astigmatism and larger astigmatic axis shift on the VISX platform as compared to the LADAR CustomCornea and the LADAR and VISX conventional platforms. Care should be emphasized mainly during registration/alignment to minimize surgically induced astigmatism in wavefront-guided LASIK.
Journal of refractive surgery (Thorofare, N.J.: 1995) 21(6):S792-8. · 2.54 Impact Factor
