Clinical quality assessment using computer monitor photoimages of optic nerve head cupping.

BACKGROUND: Photo documentation (color slides) of abnormal optic nerve heads enable the clinician to accurately access or estimate the percentage of the optic nerve cupping to quantify the progression of glaucoma. The purpose of this study is to compare cupping estimations using digital images on a computer monitor to those using standard color slides. METHODS: Ten sets of stereo optic nerve head photos from six glaucoma suspects were used in this study. A set is two 35-mm pictures of one optic nerve head. The film was developed as standard color slides using Seattle Filmworks slide developing. The computer monitor photoimages used Seattle Photoworks software for photos on disk. Thirteen experienced examiners estimated cupping on the 10 sets of color slides and on the 10 sets of digital images. Standard criterion was used to estimate the C/D percentage. We used a three-way mixed model ANOVA experimental design to analyze the data. RESULTS: Examiner estimations of C/D differed slightly between color slides and computer monitor photoimages (mean C/D of 61.1% for slides to 63.7% for monitor). This difference was statistically significant (p = 0.033). The differences authors found were not clinically significant (10%) in 7 out of the 10 optic nerve head photos using the accepted standard of interexaminer reliability. The variations of the examiner estimations as well as interexaminer differences will be discussed. CONCLUSION: The use of a computer image photodisplay of an optic nerve head has a potential as an alternative to traditional slide photodocumentation. This study identifies problems which require more work to make these computer images the equivalent of color slides.

Clinical comparison of the SITE IRAS hand-held interferometer and Haag-Streit Lotmar visometer.

The preoperative testing of retinal acuity was evaluated using two instruments in each of 35 eyes having extracapsular cataract extraction. Retinal acuity was measured using the SITE IRAS hand-held interferometer and the Haag-Streit Lotmar visometer. The postoperative findings are given for comparisons of final acuity, prediction, and instrument evaluation. The results showed predicted acuity to be within two lines of the final acuity in 57.1% of eyes with the Haag-Streit unit and in 42.8% of eyes with the SITE instrument. The instrument differences were more in procedure than in results.

Prospective evaluation of radial keratotomy using the Fyodorov formula: preliminary report.

Eighteen eyes were preoperatively evaluated and operated on by the method of Fyodorov. Although Fyodorov stated that his formula improves the predictability of radial keratotomy, we know of no previously published studies that included it. They all omitted the Maklakov measurement of scleral rigidity, although Fyodorov stated that it may influence the surgical result profoundly. Maklakov measurement of scleral rigidity does not correlate with Schiotz measurement of scleral rigidity. The overall predictability of the formula at six to 14 months postoperatively was good except in the eyes of a diabetic patient. The formula enables the surgeon to show the patient preoperatively what his likely result will be. Sixteen of 17 eyes (94%) in the refraction range of -2.00 to -7.50 had a visual acuity of 20/50 or better. The patient satisfaction rate was excellent. There were no important complications. Subjective glare and glare independently measured with the Miller-Nadler glare tester was absent in all tested eyes except one eye when it was dilated. Radial keratotomy as described here is safe, effective, and reasonably predictable and may be offered to selected patients who have personal requirements that are not fulfilled by standard optical devices.