Peer-reviewed Articles

Please use the archived list on the right to look at past peer-reviewed articles.


Chen,H., Ge,J., Liu,X., Lu,F. The clinical analysis of 260 combined surgery of glaucoma and cataract. Yan ke xue bao = Eye science / "Yan ke xue bao" bian ji bu 2000;16,2:102-105. [ Show Abstract ]

PURPOSE: To evaluate the efficacy of the combined surgery of glaucoma and cataract. METHODS: We reviewed 260 consecutive cases (279 eyes) who underwent the combined procedure of glaucoma and cataract. The patients were divided into three groups: group 1: extracapsular cataract extraction combined with trabeculectomy; group 2: extracapsular cataract extraction and intraocular lens implantation combined with trabeculectomy; group 3: cataract phacoemulsification and intraocular lens implantation combined with trabeculectomy; We analyzed and compared the postoperative visual acuity (VA), intraocular pressure(IOP) and complications among three groups. RESULTS: 16.2%, 32.4% and 43.5% of patients in three groups achieved 0.3 or better VA. The VA improved rate were 46.6%, 70.4% and 78.3% respectively. The mean postoperative IOP of three groups were 12.72 +/- 6.66 mmHg(1 mmHg = 0.133 kPa), 13.01 +/- 5.26 mmHg, 12.63 +/- 4.66 mmHg(compared with preoperative IOP, P < 0.01). The complications of group 3 were much less than those of the other two groups. CONCLUSION: The combined surgery can control the IOP effectively; The triple procedure can improve the VA rapidly and the phacoemulsification technique can decrease the complications.

Chong,T., Simpson,T., Fonn,D. The repeatability of discrete and continuous anterior segment grading scales. Optometry and Vision Science 2000;77,5:244-251. [ Show Abstract ]

Purpose: To investigate the repeatability of three anterior segment clinical grading scales: 1) verbal descriptors scale (VDS), 2) photographic matching scale (PS), and 3) continuous matching scale (CS). Methods: Five optometrists graded 30 slides each of 3-9-o'clock staining, bulbar redness, and palpebral conjunctival roughness twice, separated by at least a day. VDS and PS were five-point scales (0-4.) with half grades permitted. The CS was a 5-second, 240-frame video movie generated using morphing software. PS and CS grading was done with references presented on a computer screen. Results: Averaged across observers, the test-retest intraclass correlation, correlation coefficient of concordance, and Pearson's r ranged from 0.95 to 0.99 (all p < 0.001). Coefficients of repeatability using CS to grade all three ocular conditions ranged between 0.31 and 0.49. The corresponding PS and VDS coefficients of repeatability ranged between 0.37 and 0.49; PS generally had better repeatability than VDS. Conclusions: Each of the clinical grading scales was reliable. The coefficients of repeatability showed that bulbar redness and palpebral conjunctival roughness were graded with higher precision using CS.

Dumbleton,K., Jones,L., Chalmers,R., Williams-Lyn,D., Fonn,D. Clinical characterization of spherical post-lens debris associated with lotrafilcon high-DK silicone lenses. CLAO Journal 2000;26,4:186-192. [ Show Abstract ]

Purpose: Experience with high Dk silicone hydrogel lenses has revealed post-lens debris, which is characterized by the appearance of spherical, translucent particles referred to as 'mucin balls.' The objectives of this analysis were to characterize the presence of mucin balls, determine whether any ocular characteristic predicts the development of mucin ball debris, and determine whether there is any association between mucin balls and the ocular response to contact lens wear. Methods: Ninety-two subjects wore lotrafilcon A lenses on an extended wear basis for up to 30 nights and were followed for 6 months. Mucin balls were graded on a 0 to 4 scale at three visits. Subjective ratings and biomicroscopic appearance were recorded at all visits. Results: Mucin balls were observed in 70% of subjects at one or more visits, and 29% of subjects at all three visits. There was no change in the mean grade of mucin balls over time. Mucin balls were graded > 1 in 20% of eyes, > 2 in 6% of eyes, and > 3 in 2% of eyes. Subjects who exhibited mucin balls at each clinical visit had significantly steeper keratometry readings along the flatter meridian (44.3 D) than those who never exhibited mucin balls (42.9 D, P<0.0001). The percentage of subjects who 'never' use lubricating drops was higher in the subjects with mucin balls (P=0.0014). No association was found between mucin ball observation and biomicroscopic appearance, inflammatory responses, or subjective responses. Conclusions: The presence of mucin balls does not appear to be detrimental to contact lens wear. Eyes with steeper corneal curvature were significantly more likely to present with mucin ball debris, indicating they may be a function of lens fit. Clinical factors that may be modified in order to menage the more severe presentation of mucin balls are the use of lubricating drops and the number of nights extended wear schedule.

Hrynchak,P., Simpson,T. Optical coherence tomography: An introduction to the technique and its use. Optometry and Vision Science 2000;77,7:347-356. [ Show Abstract ]

This report describes the new optical imaging technique of optical coherence tomography (OCT). OCT is capable of high-resolution, micrometer-scale, cross-sectional imaging of biological tissue. The OCT for ophthalmic application uses 843-nm, near-infrared light, which produces a longitudinal resolution of 10 to 20 μm and a penetration depth of a few millimeters. The scans are displayed in a false color representation scale on which warm colors represent areas of high optical reflectivity and cool colors represent areas of minimal or no reflectivity. A cross-sectional view similar to a histology section is obtained. The cornea, iris, and lens may be visualized as well as the retina and optic nerve. OCT has been used to investigate several ocular diseases. These include macular disease, genetic retinal disease, retinal detachment and retinoschisis, choroidal tumors, optic nerve disorders, and glaucoma.

Pritchard,N., Jones,L., Dumbleton,K., Fonn,D. Epithelial inclusions in association with mucin ball development in high-oxygen permeability hydrogel lenses. Optometry and Vision Science 2000;77,2:68-72. [ Show Abstract ]

Debris trapped behind contact lenses may be associated with adverse reactions in extended wear. Although streaks and clumps of cellular material have been reported after overnight wear of conventional materials, recent experience with several high-oxygen permeability (Dk), silicone-containing hydrogel lenses indicates that certain participants are prone to the development of a unique back surface debris. This debris forms as spherical, translucent entities and results in depressions within the ocular surface after lens removal. Little information is known about these spherical bodies, particularly with respect to their composition and development. In this report, we provide photographic evidence of this debris (sometimes termed 'mucin balls' or 'lipid plugs'), discuss its differential diagnosis and describe a case in which material seems to be embedded in the epithelium as a direct consequence of their presence.

Situ,P., Elliott,D. B. The detection of change in stereoacuity. Chinese Journal of Optometry and Ophthalmology 2000;2,4:216-218. [ Show Abstract ]

Objective: To compare the repeatability of the Frisby, Randot and Howard-Dolman stereotests, and to determine the 95% confidence limits for the change of each test. Methods: Stereoacuity using the three clinical stereoacuity tests was measured in 26 healthy adult subjects with normal binocular vision. The subjects were retested approximately one week later. Results: The coefficients of repeatability for the three tests were ±2.7" (Frisby) ±8.0" (Randot) and ±9.3" (Howard-Dolman) and test-retest correlation coefficients were 0.91 (Frisby), 0.56 (Randot), and 0.60 (Howard-Dolman). Conclusion: The Frisby test showed the best repeatability and smallest range of normal values. For young adults, the 95% confidence limits for change were calculated to be ±2.7". If a young adult's stereoacuity measured with the Frisby test changes by more than this amount, then this should be considered a significant clinical change.

Sorbara,L., Chong,T., Fonn,D. Visual acuity, lens flexure, and residual astigmatism of keratoconic eyes as a function of back optic zone radius of rigid lenses. Contact Lens and Anterior Eye 2000;23,2:48-52. [ Show Abstract ]

The purpose of this study was to determine whether the visual acuity of keratoconic eyes was affected by alteration of back optic zone radii (BOZRs) of rigid gas permeable lenses (RGP) contact lenses. Visual acuity, spherical and sphero-cylindrical over-refraction and keratometry of the front surface of the RGP lenses of nine keratoconic eyes were measured. The BOZR of the five lenses varied from steeper to flatter than that habitually worn by the subjects. The steepest lenses produced significantly greater lens flexure and residual astigmatism (P<0.002) and worse high and low contrast visual acuity with the spherical over-refraction (P<0.05). There was no statistical difference in visual acuity across the range of BOZR when a sphero-cylindrical over-refraction was applied. Thus reduced visual acuity in keratoconus with steep lenses is likely due to uncorrected residual astigmatism from a combination of several possible sources. © 2000 British Contact Lens Association.