Tanja Coeckelbergh

Association of lens opacities, intraocular straylight, contrast sensitivity and visual acuity in European drivers

Purpose:  To study the relationship between lens opacity and intraocular straylight, visual acuity and contrast sensitivity.

Continuous positive airway pressure therapy is associated with an increase in intraocular pressure in obstructive sleep apnea

PURPOSE Several reports have demonstrated an association between glaucoma and obstructive sleep apnea (OSA), though the origin of this association remains unknown. In the present study, the influence of OSA and continuous positive airway pressure (CPAP) therapy on intraocular pressure (IOP) and ocular perfusion pressure (OPP) was examined. METHODS IOP, blood pressure, and pulse rate were measured every 2 hours during 24-hour sessions in 21 patients with newly diagnosed OSA. A first series of measurements was performed before CPAP therapy, and a second series was performed 1 month after the initiation of CPAP therapy. OPP was then calculated. RESULTS Baseline measurements showed a significant nycththemeral fluctuation in the average IOP, with the highest IOPs at night. After 1 month of CPAP therapy, the average IOP was significantly higher than baseline. The increase in overnight IOP was also significantly higher. A 24-hour IOP fluctuation of > or =8 mm Hg was found in 7 patients at baseline and in 12 patients during CPAP therapy. The mean difference between trough and peak IOP was 6.7 +/- 1.5 mm Hg at baseline and 9.0 +/- 2.0 mm Hg during CPAP therapy. Thirty minutes after CPAP cessation a significant decrease in IOP was recorded. There was a statistically significant decrease in mean OPP during CPAP therapy. CONCLUSIONS Patients with OSA demonstrated significant 24-hour IOP fluctuations, with the highest values at night. CPAP therapy causes an additional IOP increase, especially at night. Regular screening of visual fields and the optic disc is warranted for all patients with OSA, especially those treated with CPAP.

Surgical outcomes of intraocular lens exchange : Five-year study

PURPOSE: To report the indications, surgical complications, and outcomes of intraocular lens (IOL) exchange procedures performed over 5 years and to correlate the incidence of perioperative anterior vitrectomy in eyes previously treated by neodymium:YAG (Nd:YAG) laser capsulotomy. SETTING: Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium. METHODS: In this prospective study, all IOL exchange procedures performed between October 2002 and December 2007 were included. Surgical outcomes were correlated with indications, IOL position, targeted versus achieved refraction, preoperative Nd:YAG laser capsulotomy, and surgical complications. RESULTS: One hundred twenty‐eight eyes (113 patients) had IOL exchange because of IOL opacification (31%), IOL decentration (19%), IOL dislocation (18%), capsule phimosis (14%), corneal endothelial cell decompensation (8%), IOL miscalculation (6%), damaged IOL (2%), or IOL‐related chronic uveitis (2%). Before and after IOL exchange, respectively, the IOL was capsule fixated in 82% and 45% of eyes, iris fixated in 4% and 39% of eyes, and sulcus fixated in 7% and 15% of eyes. Iris‐fixated IOLs had the lowest predictability of refractive outcome (mean 1.55 diopters). Intraocular lenses implanted using the bag‐in‐the‐lens technique had the highest refractive outcome predictability (mean 0.51 D). CONCLUSIONS: Decentration of pseudoaccommodating IOLs accounted for 14% of all IOL exchanges. Vitreous loss necessitating anterior vitrectomy was strongly correlated with preoperative Nd:YAG laser capsulotomy. Postoperative visual acuity improved in all cases without preoperative ocular comorbidity.

Cumulative neodymium:YAG laser rates after bag-in-the-lens and lens-in-the-bag intraocular lens implantation: comparative study.

PURPOSE: To study the cumulative neodymium:YAG (Nd:YAG) laser rate after bag‐in‐the‐lens implantation (Morcher 89A) and lens‐in‐the‐bag implantation (Morcher 92S) of 2 intraocular lenses (IOLs) of the same biomaterial. SETTING: Department of Ophthalmology, University Hospital of Antwerp, Edegem, Belgium. METHODS: This study comprised 100 eyes of 87 patients who had the bag‐in‐the‐lens IOL implantation between January 2000 and August 2004. The postoperative follow‐up ranged between 17 and 72 months. One hundred eyes of 94 patients of the same age and with the same follow‐up period received the lens‐in‐the‐bag IOL. The cumulative Nd:YAG laser frequency rates in both groups were calculated, and the cumulative incidence rates were defined by Kaplan‐Meier survival analysis. RESULTS: No Nd:YAG laser capsulotomy was performed in eyes having bag‐in‐the‐lens IOL implantation. A laser capsulotomy was performed in 20 eyes having lens‐in‐the‐bag IOL implantation; the cumulative frequency in this group was 2% at 1 year and 20% at 71 months, with a plateau beginning at 42 months. The cumulative incidence rate of Nd:YAG posterior capsulotomy was approximately 2% at 1 year, increasing to approximately 28% at 42 months. CONCLUSIONS: The cumulative Nd:YAG laser rate after bag‐in‐the‐lens implantation was zero. A zero rate has not been reported with lens‐in‐the‐bag implantation of an IOL of the same biomaterial or of other biomaterials, as published in the literature. Thus, it can be concluded that the bag‐in‐the‐lens implantation technique has 100% effectiveness against posterior capsule opacification.

Influence of cataract morphology on straylight and contrast sensitivity and its relevance to fitness to drive.

Aims: To evaluate straylight and contrast sensitivity in cataractous eyes of different morphologies, and to determine which type of cataract presents higher impairment of visual function, specifically compared to studies proposing new norms for European drivers. Methods: Best-corrected visual acuity (BCVA), contrast sensitivity and straylight were measured in 97 cataractous eyes using respectively a Snellen chart, a Pelli-Robson chart and the compensation comparison method (C-Quant Straylight Meter). Cataracts were graded using the Lens Opacities Classification System III (LOCS III) and divided into 4 groups: nuclear, cortical, nuclear-cortical and posterior subcapsular cataract. These results were compared to data from 38 cataract-free control subjects. Results: Contrast sensitivity was reduced and straylight increased in all cataract patients, most notably in posterior subcapsular and nuclear-cortical cataract. Contrast sensitivity and BCVA were correlated (r = 0.44), whereas straylight and BCVA were not. Applying cut-off values as proposed by European drivers studies of 1.25 log contrast sensitivity and 1.4 log straylight as safe margins for driving, 31% would be considered unfit to drive on the basis of contrast sensitivity and 78% on the basis of straylight, although their visual acuity was still above the current European visual acuity requirement for driving. Conclusions: Straylight and, to a lesser extent, contrast sensitivity are complementary to BCVA and should be taken into account when considering surgery or driving legality.

Intraocular lens centration and visual outcomes after bag-in-the-lens implantation

PURPOSE: To examine the centration and visual outcomes after cataract surgery using the bag‐in‐the‐lens (BIL) implantation technique. SETTING: University Hospital Antwerp, Department of Ophthalmology, Edegem, Belgium. METHODS: This study comprised 180 eyes of 125 patients who had cataract surgery with implantation of the BIL intraocular lens (IOL) between March 2002 and September 2005. Postoperative data at 5 weeks, 6 months, and 1 year were evaluated. The geometric center of the IOL, measured on a red reflex slitlamp photograph, was compared with the geometric center of the pupil and the limbus. RESULTS: The mean decentration compared with the limbus was 0.304 mm ± 0.17 (SD) at a mean angle of −24.9 ± 113.3 degrees. Compared with the dilated pupil, the mean deviation was 0.256 ± 0.15 mm at a mean angle of −5.2 ± 119.0 degrees. The amount of decentration was stable during the postoperative follow‐up period. There was no correlation between the amount of decentration and the visual outcomes (pupil: r = −0.07, P = .494; limbus: r = 0.11, P = .304). CONCLUSIONS: Surgeon‐controlled BIL centration was predictable 5 weeks and unchanged 6 months and 1 year postoperatively. It can therefore be concluded that capsular bag healing has no influence on BIL IOL centration over time.

PREVALENCE OF IMPAIRMENT OF VISUAL FUNCTION IN EUROPEAN DRIVERS

Purpose:  This study aimed to investigate the prevalence of impairment of visual function amongst European drivers.

Straylight before and after LASEK in Myopia: Changes in Retinal Straylight

PURPOSE To quantify the changes in retinal straylight that occur after laser-assisted subepithelial keratectomy (LASEK). METHODS This prospective study included 86 eyes of 49 patients who were scheduled for LASEK surgery. Patients were divided into groups based on their preoperative contact lens wear habits: rigid lenses (RCL), soft lenses (SCL), spectacles after a period of contact lenses (SaC), and spectacles only (Specs). Retinal straylight was tested before surgery and 6 months after surgery with the compensation comparison method. Straylight was also compared to a normal reference database. The difference with the average straylight increase with age, called base- and age-corrected (BAC) straylight, was also studied. RESULTS Before surgery, BAC straylight was found to be strongly elevated, with a value of 0.15 +/- 0.14 log units. After LASEK, this decreased to 0.00 +/- 0.14 log units. The reduction was significant (paired t-test, P << 0.01) and correlated with preoperative BAC straylight levels (r(2) = 0.332; P << 0.01). There was no correlation between the straylight change and the spherical equivalent of the laser refractive correction (r(2) = 0.042; P = 0.059). Preoperative wear of soft contact lenses increased the BAC straylight by approximately 0.06 log units, with respect to the spectacles groups (P < 0.05, unpaired t-test), but after surgery, this difference was no longer found (P > 0.05). CONCLUSIONS Higher than normal preoperative BAC straylight was found to normalize after LASEK refractive surgery. Wearing soft contact lenses causes an additional increase in preoperative BAC straylight that is eliminated after LASEK.

Cataract and pseudophakia in elderly European drivers.

Purpose To evaluate the prevalence and association of different types and seventies of cataract or pseudophakia with visual impairments in older European drivers. Methods In this prospective European multicenter study, 2211 active drivers, 45 years of age and older, participated in an ophthalmologic examination, the measurement of visual functions, and were asked to fill in the NEI-VFQ-25 and another questionnaire about driving habits, driving difficulties, and self-reported accidents. Results Prevalence of moderate and severe forms of cataract in an active driving population is lower than that in the general population, but could be found in both eyes in 20% (95% confidence interval [CI] 16%–25%) and 17% (95% CI: 13%–21%) of subjects 75 years of age and older. In addition, there is a strong relationship between severity of cataract and parameters such as age, visual acuity, intraocular straylight, and contrast sensitivity. Conclusions Cataract is not as highly prevalent in the elderly active driving population as in the general population, but is frequently present in drivers over 65 years of age. Lower prevalence of severe bilateral cataracts in countries with mandatory tests of visual functions of drivers suggest that this could be a suitable measure to detect and to reduce the number of active drivers with severe bilateral cataracts.

Retinal straylight before and after implantation of the Bag in the Lens IOL.

PURPOSE To quantify the changes in retinal straylight that occur after implantation of the Bag in the Lens (BIL) IOL, which by design avoids the formation of posterior capsule opacification or any influence of the posterior lens capsule. METHODS This prospective study included 81 eyes of 53 cataract patients planned for surgery with the BIL. Preoperatively and 6 months postoperatively their straylight level was determined using the compensation comparison method. RESULTS After implantation of the BIL straylight significantly improved from 1.59 ± 0.26 preoperatively to 1.19 ± 0.21 log units postoperatively (paired t-test, P < 0.001). Postoperative straylight was within age-normal levels in 56.1% of the eyes and went below age-normal values in 40.2% of the eyes. Average postoperative straylight remained 0.27 log units (or 1.87×) above the age-independent base straylight value of 0.931 + 0.200. Postoperatively straylight was not significantly correlated with age (r(2) = 0.001), but it was significantly correlated with a regression model that combines both age and axial length (r(2) = 0.199). CONCLUSIONS Retinal straylight after implantation of the BIL is comparable to what has been published for the early follow-up of other IOL types, suggesting that a clear posterior lens capsule does not seem to add to straylight. However, for all IOL types average postoperative straylight remains above the expected base level, possible due to nonlenticular age-related parameters or to the physiological response of the ocular tissues to the surgical act. This should be examined in further detail in future studies.