Björn L. Lundh

Cataract surgery and quality of life in patients with age related macular degeneration

Background: The coexistence of cataract and age related macular degeneration (AMD) is not unusual, especially in the very elderly. The outcome of cataract surgery in these cases depends on the effect of AMD on vision. In this study the authors have compared the outcome of cataract patients with AMD to that of cataract patients with no vision threatening ocular comorbidity, and analysed possible predictors of good or poor outcome. Methods: An observational prospective study on consecutive cases operated for cataract during 1 month at six surgical departments affiliated to the Swedish National Cataract Register (NCR). Data were collected according to the protocol of NCR and subjects completed the Catquest questionnaire before and 6 months after surgery. 90 subjects with AMD were compared to 335 subjects with no sight threatening ocular comorbidity. Results: Difficulties in performing various daily life activities improved significantly for AMD subjects after surgery (p<0.001, Wilcoxon signed rank test). Satisfaction with vision also improved significantly after surgery (p<0.001, Wilcoxon signed rank test). Activity level and independence were unchanged. Subjects with no ocular comorbidity had a still better outcome. The most important variable related to a good self assessed functional outcome was postoperative visual acuity irrespective of the presence of AMD. AMD subjects scheduled for second eye surgery and AMD subjects dissatisfied with their vision before surgery had a poorer outcome. Conclusion: Subjects with various stages of dry AMD and cataract improved their self assessed visual function and satisfaction with vision significantly after cataract extraction.

Central and peripheral normal contrast sensitivity for static and dynamic sinusoidal gratings.

Contrast sensitivity for moving and stationary sine grating patterns was determined in central and peripheral parts of the visual field. The method was primarily developed as a possible screening procedure for visual defects in glaucoma. Contrast sensitivity to moving patterns seemed maximal both in central and in 10 degrees of eccentric viewing for square wave reversals of temporal frequencies 0.5‐5 Hz. We selected 2Hz for the clinical procedure. Further, we have determined normal central and peripheral contrast sensitivity in 10 subjects 61–71 years‐old, to serve as a basis for the glaucoma studies. We used this age group since glaucoma mainly affects elderly people. We confirmed that contrast sensitivity was higher for dynamic than for static presentation of gratings of low spatial frequencies (below 1 c/d) both centrally and peripherally. For patterns of medium or high spatial frequencies, dynamic and static stimuli were equally detectable. The absolute level of contrast sensitivity was higher centrally than peripherally in the interval 0.3–4 c/d. The lower visual hemifield exhibited greater sensitivity, for both static and dynamic gratings, than the upper one.

Central and peripheral contrast sensitivity for static and dynamic sinusoidal gratings in glaucoma

Abstract. Contrast sensivity testing in glaucoma patients was extended from central, static patterns to include peripheral areas and dynamic gratings. The results were compared with age‐matched normals in visuo‐grams, and sensitivity defects were correlated to the location of visual field defects. Tested spatial frequencies included 0.3, 0.5 1, 2 and 4 c/d. Definite sensitivity losses for all spatial frequencies were found for dynamic patterns in testing positions located 10° eccentrically above and below fixation. For static patterns in the periphery sensitivity was reduced only for medium spatial frequencies. For central viewing, reduced sensitivity was found with dynamic medium spatial frequencies only. No centrally presented static gratings were of subnormal sensitivity. Dynamic patterns in the periphery were superior to other combinations regarding the capacity for indicating the presence of glaucomatous influence. Peripheral sensitivity losses also occurred when perimetric disturbances were located outside the area tested in the same hemi‐field. Depressed sensitivity was observed even in hemifields with normal/near‐normal perimetric fields. These findings might be indicative of an early glaucomatous impairment. It thus seems that testing peripheral dynamic contrast sensitivity might be a potentially valuable method for glaucoma screening.

IMPROVEMENT OF CONTRAST SENSITIVITY FROM TREATMENT FOR AMBLYOPIA

Twenty‐four amblyopic children were treated with grating visual stimulation. In eight of them visual acuity did not change. However, four of these eight children showed improved contrast sensitivity.

Lens changes in matched normals and hyperlipidemic patients treated with simvastatin for 2 years.

Abstract. Simvastatin, a potent blood lipid reducer, has been suspected of inducing cataract in dogs. Twenty‐nine type II hyperlipidemic patients on simvastatin were followed over 2 years at half‐year intervals. A parallel group of sex‐ and age‐matched normolipidemics were followed over a half year. Patients and controls had similar nuclear and cortical lens opacities, and water clefts. Vacuole number did not differ significantly between right and left eyes, nor between nasal and temporal parts of the lenses. General vacuole index (total vacuole number in a patient) for left eyes was analysed further. Controls showed significantly higher indices than patients, for no obvious reason. Indices for controls increased significantly over the half‐year test period, and among patients over each half‐year interval. The speed of this increase did not differ significantly from that of the controls. Furthermore, the increase was judged to be clinically insignificant. No deleterious effect of simvastatin on the lens could be established.

PICTURE SIMULATION OF CONTRAST SENSITIVITY IN ORGANIC AND FUNCTIONAL AMBLYOPIA

We have tried to illustrate some contrast sensitivity defects by picture simulation. We have used data obtained from 2 patients: a woman with optic nerve lesion (Snellen VA 0.5) and a 7.5‐year‐old boy with anisometropic amblyopia (VA 0.6). The optic nerve lesion was represented by profound contrast sensitivity loss for all spatial frequencies, while the anisometropic eye showed loss only at high spatial frequencies. A positive picture was decomposed into 1.25 × 106 pixels (picture elements), using a drum scanner. In a computer each spatial frequency component of the picture was multiplied by the ratio between the patient sensitivity value and that of an age‐matched reference group and a modified image was processed. The pictures illustrate the poor image quality that is associated with general contrast sensitivity loss, even when Snellen visual acuity is only moderately impaired.

EFFECTS OF AMBLYOPIA THERAPY ON CONTRAST SENSITIVITY AS REFLECTED IN THE VISUOGRAM

A quantitative evaluation of the Cambridge amblyopia treatment on contrast sensitivity was performed for 2 groups, one comprising 11 children with strabismic amblyopia (S) and another of 10 children with combined strabismic and anisometropic amblyopia (S & A). Contrast sensitivity deficits were expressed in dB CSL (Contrast Seeing Level) in relation to normal sensitivity of the same age group and represented in the form of visuograms. Mean contrast sensitivity losses in dB CSL were estimated within the low, medium and high spatial frequency ranges, as well as over the total frequency band. On an average S & A amblyopia was found to affect contrast sensitivity of all spatial frequencies, while S amblyopia affected mainly the higher frequency band, but to a smaller extent. After therapy average contrast sensitivity improved for both S and S & A groups, and reached the same, subnormal levels. The relation between highest resolvable spatial frequency (according to our method) and Snellen acuity was different for the 2 amblyopia groups. No correlation was found between improvements in contrast sensitivity and Snellen acuity, which is why both parameters should be estimated.

Postoperative aphakia in modern cataract surgery - Part 2 : Detailed analysis of the cause of aphakia and the visual outcome

Purpose: To study the incidence of aphakia after cataract surgery, the surgical complications that can lead to it, and the visual outcome. Setting: Six community‐run eye clinics participating in the Swedish National Cataract Register. Methods: Data on cataract extractions were collected prospectively from 1997 through 2001. The data also covered the type of surgery and type of intraocular lens, including a “no lens implanted” option. All data were stored in a database. These data were supplemented with data on the intended type of surgery, type of complications, possible second surgery, and visual outcome. Results: The overall incidence of postoperative aphakia was 0.65%. In 87.1% of cases, the aphakia was not planned, corresponding to an incidence of 0.48%. Unplanned aphakia was significantly related to poor preoperative vision, old age, and the presence of ocular comorbidity. The most frequent reasons for unplanned aphakia were intraoperative capsule problems and vitreous loss. In two thirds of cases, a second operation was performed. In 41% of all cases, the final visual acuity was 0.5 or better and in 27.7%, worse than 0.1. Conclusions: During the study period, 1 of every 200 routine cataract surgeries ended in unplanned aphakia. The incidence of surgical complications leading to unplanned aphakia and a final visual acuity worse than 0.1 (20/200) was 7.8 per 10000 operations in cases with no ocular comorbidity and 27.6 per 10000 operations in cases with ocular comorbidity.

Postoperative aphakia in modern cataract surgery. Part 1: Analysis of incidence and risks based on 5-year data from the Swedish National Cataract Register

Purpose: To study the incidence of aphakia after cataract extraction and evaluate the relative risk for this outcome in subgroups of patients based on preoperative conditions. Setting: Sixty‐two community‐run or private clinics participating in the Swedish National Cataract Register. Methods: Data on cataract extractions were collected prospectively from 1997 through 2001. The set of data also covered type of surgery and type of intraocular lens (IOL), including a “no lens implanted” option. All data were stored in a database. Database calculations were made of frequencies and risk ratios of postoperative aphakia in the subgroups of patients based on preoperative conditions. Results: For the entire study period, postoperative aphakia was reported in 1410 of 287951 surgeries for which complete IOL data were available, corresponding to an overall frequency of 0.49%. The occurrence of ocular comorbidity and poor preoperative visual acuity (≤0.1) in the eye to be operated on was significantly related to postoperative aphakia for each year of the study (P<.001). Glaucoma and poor visual acuity (≤0.1) in the surgical eye meant a 12.8 higher risk for aphakia after surgery than a better visual acuity (>0.1) and no ocular comorbidity. Conclusions: This national 5‐year survey showed that in routine cataract surgery performed during the study, 1 of every 200 operations ended in postoperative aphakia. Poor visual acuity (≤0.1) in the eye to be operated on combined with ocular comorbidity was the highest risk factor for postoperative aphakia.

Endothelial cell density after penetrating keratoplasty using long-time banked donor material after long distance transportation (Denmark-Sweden)

Abstract Central corneal cell density was evaluated from photographs obtained by a clinical non‐contact specular microscope (Zeiss) in 48 patients at a mean post‐operative time of 7 1/2 months after penetrating keratoplasty for a number of different causes, keratoconus being the most frequent indication. Cell density decrease on this occasion was compared to pre‐operative data from the Eye Bank in Århus, Denmark, which supplied corneo‐scleral preparations transported by ferry and train to Linköping, Sweden. A mean decrease in cell density of 4.4% was recorded during bank time (11–27 days). A further mean decrease from final preparation to post‐operative photography of 36.5% was found. Mean total cell density decrease amounted to 39.4%, which compares well with results found in other studies. Among several factors studied, the only one associated with significantly (P < 0.02) greater cell density decrease than other factors was long post‐mortal time periods (death to bank preparation). Mean final endothelial cell density was 1899 cells/mm2, which should correspond to a good functional reserve of donor endothelium. Neither the long bank time, nor the transportation seemed to be of major importance with respect to donor material quality. Foreign material supply can be a good solution to local corneal shortage.