Fluorophotometry as a diagnostic tool for the evaluation of dry eye disease.

BACKGROUND: Dry eye disease is a common debilitating ocular disease. Current diagnostic tests used in dry eye disease are often neither sensitive nor reproducible, making it difficult to accurately diagnose and determine end points for clinical trials, or evaluate the usefulness of different medications in the treatment of dry eye disease. The recently developed fluorophotometer can objectively detect changes in the corneal epithelium by quantitatively measuring its barrier function or permeability. The purpose of the study is to investigate the use of corneal fluorescein penetration measured by the fluorophotometer as a diagnostic tool in the evaluation of dry eye patients. METHODS: Dry eye patients (16 eyes), who presented with a chief complaint of ocular irritation corresponding with dry eye, low Schirmer's one test (<10 mm after 5 minutes) and corneal fluorescein staining score of more than two, were included in the study. Normal subjects (16 eyes), who came for refraction error evaluation, served as controls. Institutional Review Board (IRB) approved consent was obtained before enrolling the subjects in the study and all questions were answered while explaining the risks, benefits and alternatives. All Fluorophotometry of the central corneal epithelium was done utilizing the Fluorotron Master. Each eye had a baseline fluorescein scan performed, after which 50 l of 1% sodium fluorescein dye was instilled. Three minutes later, the fluorescein was washed with 50 ml of normal saline. Fluorescein scans were then started immediately after washing and were recorded at 10, 20, 40, and 60 minutes thereafter. The corneal peak values of fluorescein concentration were recorded within the central cornea in both dry eyes and in controls. RESULTS: Ten minutes after fluorescein installation, patients with dry eye disease averaged a five-fold increase in corneal tissue fluorescein concentration (mean = 375.26 +/- 202.67 ng/ml) compared with that of normal subjects (mean = 128.19 +/- 85.84 ng/ml). Sixty minutes after dye installation, patients with dry eye disease still revealed higher corneal tissue fluorescein concentration (mean = 112.87 +/- 52.83 ng/ml) compared with that of controls (mean = 40.64 +/- 7.96 ng/ml), averaging a three-fold increase. CONCLUSION: Patients with dry eye disease demonstrated an increased corneal permeability and a slower rate of elimination to topically administered fluorescein when measured by the fluorophotometer. This suggests that fluorophotometry may serve as a valuable quantitative and objective tool for the diagnosis of dry eye disease, and in following patients' response to new treatment modalities. Fluorophotometry may serve as an objective non-invasive tool for end-point analysis in clinical trials of new treatments for dry eye disease.

Additivity of pilocarpine to bimatoprost in ocular hypertension and early glaucoma.

PURPOSE: To determine if the intraocular pressure (IOP) effect of pilocarpine at various concentrations is additive to that of bimatoprost and to assess the tolerability of this combination. METHODS: This was a randomized, prospective trial of patients with IOP > 21 mm Hg following appropriate medication washout. For all visits IOP was measured at 9:00 AM and 11:00 AM. Following baseline visit (#1), bimatoprost 0.03% was instilled qhs OU through visit 6. Following visits 2, 3, and 4 pilocarpine (2%, 4%, 6%) was instilled qid in one randomly selected eye. Pilocarpine was discontinued after visit 5 and bimatoprost after visit 6. Two-tailed, paired t test was used to compare treated and contralateral eyes for their IOP, IOP change, percentage IOP change from baseline, and to compare IOP in the same eye at 9:00 AM and 11:00 AM (before and after pilocarpine administration). IOPs using bimatoprost alone or in combination with various pilocarpine concentrations were compared using single variant Analysis of Variance (ANOVA). RESULTS: Seventeen patients were enrolled and 13 patients completed the study. Bimatoprost reduced IOP 28.7% to 30.5% (P < 0.0001) from baseline to visit 2. IOPs in eyes treated with bimatoprost alone or with bimatoprost and various pilocarpine concentrations were similar (P > 0.81, ANOVA). The IOP (P > 0.17) and percentage IOP change from baseline (P > 0.10) was similar in treated and contralateral eyes with all three strengths of pilocarpine. IOP values at 9:00 AM and 11:00 AM, before and after pilocarpine administration, were similar (P > 0.22). CONCLUSION: Bimatoprost alone reduces IOP substantially. Pilocarpine added to bimatoprost at concentrations of 2%, 4%, or 6% was neither additive nor antagonistic to the ocular hypotensive efficacy of bimatoprost.

The effect of laser iridotomy on the anterior segment anatomy of patients with plateau iris configuration.

PURPOSE: To determine if laser iridotomy altered the anterior segment anatomy of patients with plateau iris configuration. METHODS: Twenty eyes of 9 female and 1 male patients were imaged using an ultrasound biomicroscope within 19 weeks before and 52 weeks after laser iridotomy. Measurements obtained included the anterior chamber depth (ACD), trabecular-ciliary process distance (TCPD), iris thickness (IT), angle opening distance at 500 micrometers (AOD), iridozonular distance (IZD), and trabecular-iris angle (TIA). Comparisons of the pre- and post- iridotomy measurements were made using a two-tailed paired t test. RESULTS: Laser iridotomy elicited no statistically significant change in ACD, TCPD, IT, AOD, or TIA. However, IZD was decreased (P < 0.05) in both eyes after laser iridotomy. Configuration of the irides was flat before and after laser iridotomies. CONCLUSION: This study suggests that laser iridotomy did not alter anterior segment anatomy, probably because of the fixed anterior insertion of the iris and ciliary body in plateau iris configuration. The decrease in IZD distance may be the result of a small posterior movement of the iris due to a reduction in relative pupillary block, secondary to laser iridotomy. The small reduction in relative papillary block in plateau iris configuration does not alter the width of the anterior chamber angle as measured by AOD and TIA.

Videokeratography in conductive keratoplasty.

PURPOSE: We used EyeSys videokeratography to evaluate corneal shape changes induced by conductive keratoplasty, a procedure that utilizes radio frequency energy to alter corneal shape to correct hyperopia. METHODS: Follow-up data were available for 19 eyes (out of 24 eyes of 13 patients). Preoperative spherical hyperopia ranged from +0.75 to +3.25 D with astigmatism <0.75 D. Manifest refractive spherical equivalent refraction (MRSE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), topographical parameter predicted corneal acuity (PCA), corneal uniformity index (CU Index), regular astigmatism, total astigmatism, average simulated keratometry (Avg Sim K), effective refractive power, and asphericity were measured preoperatively and at 6 and 12 months postoperatively. RESULTS: Twelve months postoperatively, mean PCA, CU Index, and BSCVA were maintained at preoperative levels. Mean UCVA (LogMAR) improved from 0.53+/-0.21 to 0.10+/-0.19 (P<.05) with a mean MRSE change from +1.62+/-0.76 D to -0.06+/-0.84 D (P<.05) from preoperative to 12 months postoperative. Mean asphericity increased +0.044+/-0.24 D (P>.05), mean Avg Sim K increased 1.88+/-0.72 D (P<.05), mean effective refractive power increased 1.71+/-0.79 D (P<.05), mean cylinder (cycloplegic refraction) increased 0.19+/-0.36 D (P<.05), mean regular astigmatism increased 0.25+/-0.49 D (P>.05), and mean irregular astigmatism decreased 0.01+/-0.13 D (P>.05) from preoperative to 12 months after conductive keratoplasty. CONCLUSIONS: Avg Sim K and effective refractive power changes support the refractive results; 12-month postoperative maintenance of BSCVA, PCA, and CU Index suggest the procedure is safe. Conductive keratoplasty induced a slight regular astigmatism in some eyes, which decreased with time. The increase in mean corneal asphericity indicated possible induction of central and peripheral cornea changes.