[Efficacy of rigid gas permeable contact lens for the correction of mixed astigmatism].

PURPOSE: To evaluate the efficacy of rigid gas permeable contact lens (RGPCL) for the correction of mixed astigmatism. METHODS: Patients with mixed astigmatism by mydriasis refraction were selected as subjects. Routine eye check was performed to exclude contraindication of contact lens. Investigation included visual acuity, keratometry and corneal topography. Average keratometry value was chose as base curve of the first trial lens. Final base curve, diameter, material and edge of lens were prescribed according to the centralized position, movement and fluorescence pattern of trial lens. After over refraction, final refractive power of lens was prescribed. Corrective visual acuity with spectacle and rigid gas permeable contact lens were compared in 24 patients (31 eyes). RESULTS: Corrective visual acuity of patients with RGPCL was much better than those with spectacle. CONCLUSIONS: RGPCL is safe and effective to correct mixed astigmatism.

[Topographical evaluation on decentration of orthokeratology lenses].

OBJECTIVE: To evaluate the degree and correlative factors of decentration of orthokeratology lenses and its effect on the visual function. METHODS: Two different kinds of orthokeratology lenses were fitted to 270 eyes of 135 patients [initial mean refractive error: (-3.98 +/- 1.51) D]. Humphery Instruments ATLAS 8.0 was used for the computer-assisted analysis of corneal differential topographical maps. The examination of corneal topography was proceeded on the patients before the fitting of orthokeratology lenses and 6-month later. The distance from center of optic zone to apex of the cornea was measured as the value of decentration of orthokeratology lenses. The factors influenced the value of decentration were analyzed, including the initial refraction error, astigmatism, keratometry values, corneal eccentricity, and the diameter of the lens. The complaints of patients were recorded. Questionnaires, involving the symptoms of monocular diplopia and glare, were used to evaluate the effects of decentration of orthokeratology lenses on the visual function. RESULTS: The mean distance of decentration was (0.49 +/- 0.34) mm after one night fitting, the mean distance of decentration after follow-up for 1 month, 3 months and 6 months was (0.57 +/- 0.41) mm, (0.55 +/- 0.48) mm and (0.59 +/- 0.39) mm, respectively. After one month, the distance of decentration was less than 0.5 mm in 51.1% eyes, 0.5 - 1.0 mm in 35.6% eyes and more than 1.0 mm in 13.3% eyes. The direction of decentration in eyes with more than 0.50 mm decentration was mainly in the temporal side (48.5%). Patients with greater initial astigmatism and smaller diameter of lens showed greater distance of decentration (P < 0.05). There was no statistically significant difference in the distance of decentration between two groups with different corneal eccentricities and keratometry values (P > 0.05). The distance of decentration was greater in patients with monocular diplopia and glare. CONCLUSIONS: The degree of decentration of orthokeratology depends on the degree of initial refractive error, astigmatism and the design of orthokeratology lenses. The degree of decentration can influence the visual function.

[Refractive error and the intraocular pressure: findings in the Chinese eyes].

PURPOSE: To analysis the correlation between the refractive error and the intraocular pressure. METHODS: The IOP was measured in 142 eyes with noncontact tonometer. The refractive error were determined with an autorefractometer(TOPCON-7100). RESULTS: The analysis of variance showed that IOP of medium myopia is the highest, and a significant IOP difference between medium myopia and severe myopia, and IOP of patients less than 19yrs is significantly higher than patients more than 30 yrs; and there is also no significant influence of gender on patients' IOP, mean IOP(13.04 +/- 2.97) mmHg. CONCLUSION: These results suggest that when medium myopia IOP is relatively higher, or when a young patient less than 19 whose IOP is relatively higher than usual, that may mean the eye is under an unstable situation.

[The state of diopter and visual acuity in central serous chorioretinopathy].

PURPOSE: To investigate the state of diopter and best corrected visual acuity in active central serous chorioretinopathy (CSC). METHODS: Twenty-three unilateral active CSC patients (23 eyes) were observed with Integrated Optometry Apparatus. The period of follow-up was from 3 - 12 months (mean, 7.2 months). RESULTS: Of the 23 patients, 15 eyes (65.2%) of active CSC and 5 fellow eyes (21.7%) showed hyperopic state. There were significant differences in hyperopic state between the active eyes and fellow eyes (P < 0.01). After follow-up, there were only 5 eyes of CSC (21.7%) showed slight hyperopia. There were significant differences in hyperopic state between before and after follow-up of the eyes of CSC (P < 0.01) Among the eyes of the best corrected visual acuities were increased 3 row or above, 90.9% eyes of the best corrected visual acuities were resumed to 1.0. CONCLUSION: Most of the active CSC demonstrated temporary hyperopic state due to the neuroretinal detachment of macula. The best corrected visual acuities with the Integrated Optometry Apparatus in active CSC are useful in evaluating the final visual acuities of the eyes.