Monochromatic Aberrations in Eyes With Different Intraocular Lens Optic Designs

PURPOSE

To study the wavefront aberration profile of eyes with three different types of intraocular lenses (IOLs)--the Tecnis Z9000 (modified prolate surface design) (Pfizer, New York, NY), the Acrysof MA60BM (unequal biconvex optic) (Alcon, Ft Worth, Tex), and the Sensar Optiedge AR40e (equibiconvex optic) (AMO, Santa Ana, Calif)--in eyes following cataract surgery.

METHODS

This study was conducted in two parts. The first part was a randomized open study of 32 eyes of 16 patients who underwent bilateral phacoemulsification with a foldable IOL in the capsular bag. A Tecnis Z9000 IOL was implanted in one eye and an Acrysof MA60BM IOL in the fellow eye. The ALLEGRETTO WAVE Analyzer (Wavelight Laser Technologies AG, Erlangen, Germany) was used to measure ocular aberrations 2 weeks after surgery. A paired t test was used to compare each Zernike term from Z3(-3) to Z6(6) between fellow eyes (pupil diameter = 6 mm). In the second part of the study, the wavefront aberrations of 16 eyes that underwent an identical surgical procedure as in the first part of the study but had a Sensar Optiedge AR40e IOL implanted were studied and compared with eyes with the Tecnis Z9000 and Acrysof MA60BM IOLs.

RESULTS

The mean spherical aberration (Z4(0)) was statistically significantly lower in eyes with a Tecnis Z9000 IOL (Z4(0) = 0.07 +/- 0.12 microm) compared with eyes with an Acrysof MA60BM IOL (Z4(0) = 0.29 +/- 0.20 microm, P < .001) and with eyes with a Sensar Optiedge AR40e IOL (Z4(0) = 0.20 +/- 0.09 microm, P = .002). No statistically significant differences were noted in any of the Zernike terms between eyes with Acrysof MA60BM and Sensar Optiedge AR40e IOLs, or in the root-mean-square (RMS) of total higher order aberrations among the three IOL groups.

CONCLUSIONS

The implantation of a Tecnis Z9000 IOL produces a significant reduction in spherical aberration of the eye. No significant differences were noted in the wavefront profile between eyes with Acrysof MA60BM and Sensar Optiedge AR40e IOLs. No significant differences were found in the RMS of total higher order aberrations among the three IOL groups.

Macular pigment optical density in a Chinese sample

PURPOSE

Extensive efforts have been devoted to determining the macular pigment optical density (MPOD) in Caucasian subjects. Unfortunately, no such data in ethnic groups with naturally dark irises are currently available. In this study, we report the values in a sample of Chinese subjects.

METHODS

The MPOD was measured psychophysically using a densitometer at 0.25 degrees , 0.50 degrees , 1.00 degrees , and 2.00 degrees eccentricity from the foveal center in 92 Chinese subjects.

RESULTS

The spatial profile for the averaged MPOD was approximately exponential in form and showed a decline with age (r = -0.23). Subjects aged below 60 years had significantly higher averaged MPOD than those aged 60 years or above. Significant gender differences, in favor of males, were also found in the middle-age groups.

CONCLUSIONS

Our study reports for the first time the MPOD in a Chinese population. Baseline information on MPOD would aid future research in preventive measures against age-related macular degeneration.

Comparison of intra-articular analgesics for analgesia after arthroscopic knee surgery

Post Arthroscopic intra-articular analgesia is a better method to avoid post-operative pain after arthroscopic surgery, thus avoiding the adverse effects of systemic analgesics. In this prospective randomized double blind study conducted on 90 patients, 30 patients in group A received 20 ml of intra-articular saline, 30 patients in Group B received 10 ml of intra-articular saline and 10 ml of 0.25% bupivacaine and 30 patients in Group C received 10 ml of 0.25% bupivacaine, 1 ml (30 mg) of ketorolac and 9 ml of saline intra-articularly. Ambulatory status, duration of analgesia and requirement for supplemented analgesia were compared in these three groups. Patients receiving this intra-articular analgesic combination of bupivacaine and ketorolac required significantly less supplemental postoperative analgesics. This combination significantly prolonged the duration of analgesia. Patients receiving this combination of drugs for intra-articular analgesia ambulated earlier.

Retained presumed intraocular cotton fiber after cataract operation: long-term follow-up with in vivo confocal microscopy

PURPOSE

To evaluate the long-term clinical outcomes in eyes with retained presumed intraocular cotton fibers after cataract surgery.

SETTING

Hong Kong Eye Hospital, Hong Kong, The People's Republic of China.

METHODS

A retrospective review of 19 eyes with retained presumed intraocular cotton fibers after cataract surgery was performed. Outcome measures were fiber-related complications. In vivo confocal microscopy was performed in eyes with entrapped cotton fibers at the wound site.

RESULTS

The duration of retained presumed cotton fibers ranged from 5 to 110 months (mean 42.3 months). No complications were noted in any of these eyes, including endophthalmitis, persistent uveitis, or corneal endothelial cell loss. In vivo confocal microscopy in eyes with entrapped fibers at the wound site showed normal corneal endothelium morphology with no keratocyte activation or inflammatory response.

CONCLUSIONS

Retained presumed fibers after cataract operations are more common than anticipated. In contrast to other organic foreign bodies, these retained fibers appear to be well tolerated. Conservative treatment can be adopted for these fibers as these pose minimal toxicity to the eye.

Bilateral spontaneous rupture of Achilles tendons: a case report

Spontaneous bilateral rupture of Achilles tendon is rare. Rupture of the Achilles tendon has been described in patients on oral corticosteroid therapy. The sudden dorsiflexion of the plantar-flexed foot is the usual mechanism of injury. Spontaneous bilateral rupture is common in the degenerated tendon, which is often seen in patients with long-term corticosteroid therapy. This case is unusual because the patient has never taken steroids. We discuss the mechanism of injury and other probable causes.

Spontaneous carotid cavernous fistula in a pediatric patient: case report and review of literature

A 14-year-old boy presented with spontaneous, painless proptosis of the right eye. Computed tomography and digital subtraction angiography revealed an indirect carotid cavernous fistula. Because there were no sight-threatening complications, we adopted a conservative approach. The condition resolved 1 month after initial presentation, with angiographically confirmed spontaneous obliteration of the fistula.

Antifungal therapy for keratomycoses

Keratomycoses have recently emerged as an important cause of ocular morbidity, especially in third-world countries. Available antifungal agents are limited in their efficacy, due to limited penetration into the cornea, the fungistatic nature and the development of drug resistance. Effective usage of the available drugs is hampered by the inefficiency of currently available antibiotic sensitivity tests for fungal organisms. There is also limited knowledge regarding the ideal combination(s) of antifungal agents, including issues of synergism and antagonism. Despite these problems, recent publications indicate encouraging outcomes in the treatment of a large series of fungal keratitis. Advances include better drug formulations, new agents and novel methods of drug delivery into the eye. As our ability to deal with advanced fungal keratitis remains limited, the importance of early diagnosis has been stressed and molecular biological techniques may play an important role in the future. This article summarises the important new advances in these areas in the past 2 years and provides guidelines for the management of these serious corneal infections.

Bilateral Epithelial Defects after Laser in situ Keratomileusis. Clinical Features, Management and Outcome

PURPOSE

To describe the preoperative characteristics, intraoperative details, management, and postoperative in patients with bilateral epithelial defects after laser in situ keratomileusis (LASIK).

METHODS

Retrospective non-comparative case series.

RESULTS

Six patients with bilateral epithelial defects after LASIK were part of a cohort of 605 patients undergoing bilateral LASIK at our center from December 2001 to April 2003. The mean age of the patients (5M:1F) was 28.5 +/- 7.9 years, and the average pretreatment myopic spherical equivalent (SE) refraction was 7.3 +/- 0.7 D (-4, -12.25D). An epithelial flap was present in 6 eyes and an epithelial defect with a mean diameter of 3 mm (2mm, 6mm) was seen in 6 eyes. In four patients the epithelial disturbance was bilaterally similar. All defects occurred in the inferior cornea and the epithelial flaps had the hinge positioned superiorly. None of the patients had ocular or systemic risk factors that could have resulted in this complication. A bandage contact lens was used in 6 eyes. At last follow-up of 5.5 +/- 9.5 months (0.25, 21 months), unaided visual acuity was 6/9 or better in 10 eyes. Best spectacle-corrected visual acuity (BSCVA) was maintained in 8 eyes, while 4 eyes lost one line of BSCVA. Recurrent corneal erosions were not reported in the follow-up period.

CONCLUSIONS

These patients represent a hitherto unrecognised group of individuals who appear to have a subclinical weakness of adhesion of the corneal epithelium to the underlying structures, which is not evident on clinical examination. This results in bilateral epithelial disturbances after LASIK. Appropriate management results in satisfactory clinical outcomes. Other options for treatment of the fellow eye of such patients include the use of a different microkeratome, release of suction during the reverse pass of the Hansatome microkeratome, and photorefractive keratectomy if the refractive error is low.

Comparative study on the safety and efficacy of different cycloplegic agents in children with darkly pigmented irides

BACKGROUND

The ideal cycloplegic drug that is safe, effective and convenient in children is not yet available. This study aimed to evaluate the safety and efficacy of three cycloplegic regimens in hyperopic children with pigmented irides. The responses to cycloplegia in different age groups and presence of strabismus were also compared.

METHODS

Tropicamide 0.5% and phenylephrine 0.5% (regimen I), tropicamide 1.0% and cyclopentolate 1.0% (regimen II), and atropine 1.0% (regimen III) were evaluated in 25 children using a crossover study design. Cycloplegic refractions were assessed.

RESULTS

The mean age of the children was 5.7 +/- 2.0 years (range 2.5-10.8 years). Six (24.0%) of them had strabismus. The spherical equivalent (SE) refraction for regimens I, II and III were +5.11 +/- 2.04 D, +5.29 +/- 1.89 D and +5.71 +/- 1.90 D, respectively, and were significant different from the manifest SE (+3.95 +/- 2.17 D) (P < 0.001). There was no statistical difference between regimen I and II in children without strabismus (P = 0.258) or aged older than 5 years (P > 0.050).

CONCLUSION

In older children, regimen I was as effective as regimen II and can be used to avoid cyclopentolate toxicity.

Photorefractive keratectomy versus laser in situ keratomileusis to prevent keratectasia after corneal ablation

A 27-year-old man had excimer photoastigmatic keratectomy in the right eye and laser in situ keratomileusis in the left eye for the treatment of equivalent myopia. Preoperative slitlamp examination did not reveal evidence of keratoconus, central corneal pachymetry was 485 microm in the right eye and 500 microm in the left eye, and corneal topography revealed asymmetric bow-tie astigmatism with inferior steepening in the right eye and a small area of inferior steepening in the left eye. Twenty-two months after surgery, the patient complained of poor vision in the left eye. Slitlamp examination of the left eye revealed central corneal thinning and protrusion, with a Fleischer ring within the flap. Corneal topographic evaluation revealed a stable map in the right eye and central corneal steepening indicative of keratectasia in the left eye.

Astigmatism in Chinese preschool children: prevalence, change, and effect on refractive development

AIM

To study the prevalence, type, and progression of astigmatism in Chinese preschool children, and its effect on refractive development.

METHODS

A cross sectional study of preschool children was carried out in two randomly selected kindergartens. A cohort study was performed on a subset of children, five years after initial examination. Refractive error (measured by cycloplegic autorefraction) and axial ocular dimensions (measured by ultrasonography) were the main study outcomes.

RESULTS

522 children participated in the study; the mean age was 55.7 months (SD 10.9; range 27 to 77). Mean cylinder reading was -0.65 D (SD 0.58; range 0.00 to -4.75), and with the rule astigmatism was predominant (53%). In the 108 children studied longitudinally, the mean cylinder reading reduced from -0.62 D to -0.50 D (p = 0.019). The presence of astigmatism in initial examination predisposed the eyes towards greater myopisation (p<0.001). In addition, children with increased astigmatism had greater myopic progression (p<0.001) and axial length growth (p = 0.002).

CONCLUSIONS

This study reports a high prevalence of astigmatism in Chinese preschool children. The presence of astigmatism, and particularly with increasing astigmatism, appears to predispose the children to progressive myopia. Further studies are warranted.