Effects of Betaxolol and Latanoprost on Ocular Blood flow and Visual Fields in Patients with Primary Open-Angle Glaucoma

Purpose

To evaluate the effects of betaxolol and latanoprost on ocular blood flow and visual fields in patients with primary open-angle glaucoma (POAG) by means of an obseiver-masked, prospective clinical study.

METHODS

Thirty-two patients with newly diagnosed POAG were included in the study. The patients were randomized into two groups. The first group was treated with betaxolol 0.50% twice daily and the second group with latanoprost 0.005% once daily. Baseline and post-treatment examinations on the first and third months of treatment included intraocular pressure (IOP) measurement, automated visual field testing, and ocular blood flow assessment. For evaluation of visual fields, mean defect and pattern standard deviation indices were used. Ocular blood flow was assessed by means of color Doppler imaging of the central retinal artery (CRA) and the temporal short posterior ciliary artery (PCA). For each vessel, peak systolic (PSV) and end-diastolic (EDV) blood flow velocities were measured and resistivity index (RI) calculated.

Results

After exclusion of one noncompliant patient, the study was completed with 31 eyes of 31 patients. Both drugs significantly reduced IOP (p<0.05). The mean IOP lowering effect of latanoprost was significantly higher than that of betaxolol (p=0.03). Visual field indices exhibited no significant changes in either group (p>0.05). There were no significant changes in PSV or EDV measurements of CRA or PCA in either group (p>0.05). RI decreased in both CRA and PCA with both drugs. The mean changes between baseline and 3 month blood flow measurements were not significantly different between betaxolol and latanoprost (p>0.05).

CONCLUSIONS

Over a treatment period of 3 months, both betaxolol and latanoprost tended to improve ocular blood flow without one of them being superior to the other. The results suggest that the direct (non IOP-dependent) influence on ocular circulation is better for betaxolol than for latanoprost. In addition, neither drug caused significant generalized improvements in visual fields during this period.

Fluorescein dye disappearance test in patients with different degrees of epiphora

PURPOSE

To assess the diagnostic efficacy of a modification of the fluorescein dye disappearance test (DDT) in patients with different degrees of epiphora.

METHODS

DDT was performed by instilling a drop of 2% fluorescein in the eye. Schirmer tear test strips were placed in the lower conjunctival fornix, after 3 and 10 minutes. The colour dilution on the strips was compared to a scale with known standards and the most closely comparable colour dilution was chosen and recorded as the visual scale test (VST) grade of the strip. The grey-scale value (GV) of each strip was calculated by computer image analysis. The control group comprised 44 patients, mean age 44.8 years (SD 7.5, range 30-60). There were 13 patients in group 1 with moderate epiphora; mean age was 44.2 years (SD 9.5, range 30-60). There were 17 patients in group 2 with severe epiphora; mean age was 48.3 years (SD 7.7, range 37- 60).

RESULTS

VST and GV differed significantly between controls and group 1 patients at 3 minutes (p=0.002, p=0.001), and between controls and group 2 patients at 3 minutes (p<0.001, p<0.001). There was no difference between groups 1 and 2 patients in VST and GV at 3 minutes. The differences were highly significant between controls and group 1 at 10 minutes (p=0.001, p=0.007), and between controls and group 2 at 10 minutes (p<0.001, p<0.001). The differences in GV and VST between groups 1 and 2 were significant at 10 minutes (p=0.026, p=0.018).

CONCLUSIONS

This modified DDT permits identification of different degrees of epiphora in a non-invasive manner, it can therefore be used to evaluate the outcome of different treatment strategies.

Penetration of amikacin into aqueous humor of rabbits

Amikacin is an aminoglycoside antibiotic that has poor corneal penetration due to its hydrophilic properties. The purpose of this study was to compare and evaluate the penetration of amikacin sulfate into aqueous humor of the rabbit eye when applied by different routes and concentrations, namely 100 or 250 mg/ml topical fortified amikacin eye drops, 100 or 250 mg/ml amikacin-embedded soft contact lenses and 25 mg subconjunctival amikacin injection. One hour after application, amikacin was not detectable in any of the 100 mg/ml concentration groups. High levels of amikacin above the minimum inhibitory concentration for susceptible bacteria were detected when applied subconjunctivally and by 250 mg/ml topical fortified routes. Topical fortified amikacin 250 mg/ml reached the highest value in the aqueous (p < 0.05). Our results point out the poor corneal penetration of amikacin in standard concentrations from the intact rabbit cornea and that subconjunctival injections might provide satisfactory penetration.

Axial length measurement and asteroid hyalosis

PURPOSE

To evaluate the effect of asteroid hyalosis on automated and manual A-scan axial length measurements.

SETTING

Celal Bayar University School of Medicine, Manisa, Turkey.

METHODS

A case-control study comprised 15 patients with unilateral asteroid hyalosis. The uninvolved eyes were used as controls. Axial length measurements by manual and automated A-scan biometry were performed in both eyes. The main outcome measures were comparisons between manual and automated measurements in asteroid hyalosis eyes with those in control eyes and the assessment of density of asteroid bodies on B-scan photographs.

RESULTS

Statistical analysis revealed no significant difference between axial lengths of asteroid hyalosis eyes and those in control eyes with automated (P = .524) or manual (P = .163) methods. Using automated biometry, 1 patient (7%) had a false (6.23 mm) short axial length measurement in the eye with asteroid hyalosis. There were no significant correlations between manual versus automated measurement differences and the density of the asteroid bodies.

CONCLUSIONS

The axial length of the eye without asteroid hyalosis can be used to calculate intraocular lens power if the patient has no history of clinical anisometropia.

The influence of religious fasting on basal tear secretion and tear break-up time

Muslims abstain from food and drink from dawn to sunset during the holy month of Ramadan. An extended strict fasting may influence tear secretion and quality. We investigated changes in basal tear secretion (BTS) and tear break-up time (BUT) at the beginning and at the end of fasting on 32 healthy male patients with a mean age of 22.3 +/- 2.9 years. Body weight and urine specific gravity were also determined to assess the extent of dehydration due to fasting. Each case lost 0.1-1.25 kg of body weight while urine specific gravity changes were statistically insignificant. Mean BTS amount was 19.9 +/- 10.9 mm at the initial examination and 19.7 +/- 11.5 mm at the end of fasting (p = 0.9). BUT values were 20.1 +/- 9.3 sec at the beginning of fasting and 23.5 +/- 14.9 sec at the end of fasting (p = 0.19). We found that religious fasting in the winter season does not seem to affect BTS and BUT values in healthy individuals.

Changes in pattern reversal evoked potentials during menstrual cycle

Hormonal changes that occur during the menstrual cycle of women influence the visual function of females. Estrogen is reported to cause a decrease in the visual transmission time by increasing the sensitivity of receptors in the optic pathways to dopamine. The aim of this study was to search if pattern reversal evoked potentials (PRVEPs) changed during the different phases of the menstrual cycle. PRVEPs of both eyes of 30 healthy women were recorded in 4 different phases of the menstrual cycle, namely, menstrual, follicular, ovulatory and luteal. The highest mean PRVEP latency and the lowest mean P100 amplitude were recorded during the menstrual phase. The mean PRVEP latency recorded during the ovulatory phase (when estrogen level rises to 3-5 times that of other phases' without an increase in progesterone levels) was statistically significantly shorter than that of other phases' (p<0.05). Although not statistically significant, the mean P100 amplitude recorded during the ovulatory phase was higher than the other phases. Looking at these results, sex steroids seemed to affect the generation of PRVEPs. The significant decrease in PRVEP latencies when estrogen levels peaked was thought to be due to facilitating effect of estrogen on the neural transmission of the visual pathways.

Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy

Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A 56-year-old woman with mild dry-eye symptoms developed keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted for less than 1 day in the upper keratotomy incision. Corneal cultures yielded. Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the detection of keratitis. The inflammation was controlled with intravitreal, subconjunctival, topical, and systemic antibiotics. This case demonstrates the potential risk of endophthalmitis developing very shortly after late keratitis of AK incisions. Vigorous early treatment and close follow-up seem justifiable in any keratitis associated with a keratotomy incision.

Unilateral Refractive Keratotomy for Anisometropia

BACKGROUND

In anisometropia, the asymmetry of refractive error produces disparity of image magnification (aniseikonia) that can create visual discomfort, especially when asymmetry is 3.00 diopters or more.

METHODS

A prospective study of 20 eyes of 20 patients between 18 and 61 years of age who underwent unilateral radial and/or transverse keratotomy was conducted; results of at least 12 months follow-up are presented. The efficacy of keratotomy was evaluated by the following criteria: 1) change in spherical and cylindrical refraction, 2) decrease in refraction difference between two eyes of each patient, 3) change in spectacle-corrected visual acuity, and 4) change in binocular vision functions and asthenopic complaints.

RESULTS

Mean decrease in spherical refractive error was 3.66 +/- 1.58 D (range, 1.25 to 7.50 D) and 2.08 +/- 0.81 D (range, 1.00 to 3.50 D) in astigmatic refraction. The mean refraction difference between two eyes was 4.90 +/- 2.20 D preoperatively, and this difference regressed to 1.79 +/- 1.42 D postoperatively. Spectacle-corrected visual acuity increased in seven eyes (35%), remained the same in 12 eyes (60%) and decreased in one eye (5%). All patients reported relief of asthenopic complaints. Fusion amplitudes increased in 12 (60%) patients. Stereoscopic vision improved in five (25%) patients.

CONCLUSION

Monocular refractive keratotomy can significantly decrease anisometropia.

Monoscleral fixated lens implantation in eyes with partial loss of capsular or zonular support

A technique is described in which a posterior chamber intraocular lens (IOL) is implanted in eyes with partial loss of posterior capsule or zonular support. The IOL's inferior haptic is placed over the residual capsule and the superior haptic is fixated to the ciliary sulcus with a polypropylene suture. In 17 eyes that had surgery using this technique, mean postoperative visual acuity was 20/25; complications included irregular pupil, iris capture, pupil block, hyphema, localized peripheral anterior synechia, IOL tilt, suture exposure, and cystoid macular edema.