Smoking and neovascular form of age related macular degeneration in late middle aged males: findings from a case-control study in Japan

AIMS—The risk of smoking habits for developing the neovascular form of age related macular degeneration (neovascular form of AMD) were studied by a case-control study in Japan.
METHODS—56 male patients with the neovascular form of AMD and 82 healthy male controls, aged 50 to 69 years, were enrolled. A self administered questionnaire provided necessary information for the study subjects. Questions on smoking included whether the study subjects have ever smoked or not, and if smoked, depth of smoke inhalation, use of extra filter, age at starting smoking, average number of cigarettes smoked per day, and duration of smoking. When a smoker had stopped smoking, age at cessation was also recorded. Unconditional logistic analysis was adapted to calculate age adjusted odds ratios and their 95% confidence intervals (CIs) for smoking related factors.
RESULTS—Age adjusted odds ratio of developing the neovascular form of AMD was 2.97 (95% CI 1.00-8.84) for current smokers and 2.09 (0.71-6.13) for ex smokers, compared with non-smokers. All smoking habit/smoking history related variables such as use of extra filter, smoke inhalation level, age at starting smoking, duration of smoking, and Brinkman index were found to be significantly related to an increased risk of the neovascular form of AMD.
CONCLUSIONS—Suggested is the strong possibility that cigarette smoking enhances the neovascular form of AMD risk in late middle aged males, though the magnitude of risk by smoking variables might be overestimated, in part, because of health oriented controls.

     

Intraocular lens implants and risk of endophthalmitis

AIM—To investigate the possible association between the use of three piece foldable silicone polypropylene (SPP) intraocular lenses (IOLs) and an increased risk of postoperative endophthalmitis.
METHODS—A retrospective analysis was conducted of all cases of postoperative endophthalmitis following phacoemulsification surgery in a single unit over a 3 year period. The incidence of postoperative endophthalmitis in eyes with SPP IOLs was compared with the incidence in eyes with single piece polymethylmethacrylate (PMMA) IOLs.
RESULTS—772 cataract extractions by phacoemulsification were performed. One (0.16%) of the 622 patients with PMMA IOLs developed endophthalmitis. Excluding one patient who had aplastic anaemia, five (3.33%) of 150 patients with SPP IOLs developed endophthalmitis. The relative risk for postoperative endophthalmitis associated with the use of the SPP IOL compared with the PMMA IOL was 20.1 (p=0.015).
CONCLUSION—This study adds further evidence to the concept that SPP IOLs can be a significant risk factor in the development of postoperative endophthamitis.

Keywords: cataract surgery; phacoemulsification; intraocular lenses; endophthalmitis     

Long term clinical outcome of a randomised controlled trial of anterior chamber lenses after high volume intracapsular cataract surgery

BACKGROUND—Age related cataract remains the major cause of blindness throughout the world. In many countries, the majority of cataract surgery continues to be done by the intracapsular cataract extraction (ICCE) method. The results of a large randomised controlled trial of multiflex open loop anterior chamber intraocular lenses (ACIOL) were reported from a busy eye hospital in Nepal.
METHODS—There was a randomised controlled trial of 2000 people with bilateral cataract reducing vision to less than 6/36. Interventions were ICCE with an ACIOL compared with ICCE with aphakic spectacles (+11 dioptres). Participants were followed at discharge, 6 weeks, 1 year, and 11/2-5 years after surgery. Visual acuity and clinical outcome were measured. A poor outcome was defined as vision <6/60.
RESULTS—Visual outcome was comparable in the two groups. More of the control group experienced functional blindness due to loss of aphakic spectacles at 1 year. The majority of cases of poor outcome occurred in the first year after surgery. There was no indication of any lens related problems after 1 year.
CONCLUSION—Multiflex open loop anterior chamber lenses are safe for up to 1 year of follow up when used by experienced surgeons, and the available evidence of 2-5 years of follow up suggests that the complication rate is reasonably low. An ACIOL at the time of cataract surgery offers benefits over routine ICCE surgery with aphakic spectacle correction as it avoids the problem of replacing lost and broken spectacles.

     

A clinical study of radiation cataract formation in adult life following γ irradiation of the lens in early childhood

AIMS—To analyse long term effects on the lens of radium irradiation during infancy.
METHODS—An infant cohort (n = 20, median age 6 months) treated for skin haemangioma with one or two radium-226 needles located at or within the orbital rim was examined 30 to 45 years after γ radiation. Detailed information about the treatment procedure was available for all cases. Subcapsular opacities were graded semiquantitatively according to a scale based on extent and density of the opacities.
RESULTS—A high prevalence of light to moderate posterior, subcapsular, and cortical cataract formation was found in the lenses on the treated side irradiated with a mean dose ranging from approximately 1 to 8 Gy. The cataract formation increased as a function of dose. The presence of subcapsular punctate opacities and vacuoles in the lenses on the untreated side receiving irradiation of an estimated dose varying around 0.1 Gy indicates a higher sensitivity than expected.
CONCLUSION—The growing lens during infancy is sensitive to radium irradiation at doses lower than those previously stated. The eye lens seems suitable for studies of effects of low dose radiation since damaged cells are retained in the lens for a lifetime.

     

Heparinised intraocular infusion and bacterial contamination in cataract surgery

BACKGROUND/AIMS—Heparin in solution reduces bacterial adhesion to intraocular lenses and a lower incidence of postoperative endophthalmitis has been reported with the use of heparin coated lenses. The safety of adding low molecular weight heparin to the infusion fluid during routine cataract surgery was investigated. Any direct antibacterial effect was looked for by culturing anterior chamber fluid samples taken at the completion of surgery.
METHODS—A randomised, double blind, controlled study of 111 patients undergoing routine cataract surgery. Low molecular weight heparin at a concentration of 5 IU/ml was added to the infusion fluid in the trial patients. Samples from the anterior chamber taken at completion of surgery were cultured. Twenty nine samples of sterile infusion fluid were also cultured as further controls.
RESULTS—No complications were found in either group, and no difference in observed postoperative inflammation in each group. In the heparinised group (n=55) bacterial contamination was found in 31% of samples, compared with 27% in the no heparin group (n=56) (no significant difference).
CONCLUSIONS—There appears to be no direct antibacterial effect of heparin, and other possible mechanisms of action are discussed. Heparin avoids many of the drawbacks of traditional antibiotic prophylaxis and may have the potential to be a safe and effective addition to endophthalmitis prevention.

     

Impact of cataract surgery on car driving: a population based study in Sweden

AIMS—To investigate the outcome of cataract surgery on the patients' self estimation of visual function while driving. Furthermore, the benefit of surgery to the car driving population was determined.
METHODS—A total of 208 consecutive patients (211 cases) with driving licences, who underwent cataract surgery with intraocular lenses, were studied prospectively using self administered questionnaires. Their self estimated degree of visual functional problems while driving were analysed before and after surgery.
RESULTS—Visual problems while driving declined from 82% preoperatively to 5% after surgery. Remaining visual problems with the operated eye were present in only seven patients. Problems in estimating distance while driving decreased from 37% before surgery to 6% after surgery. Twenty three per cent of the patients drove with a visual acuity below the requirements for driving in Sweden before surgery and only 4% after surgery. There was no correlation between the degree of visual problems while driving and visual acuity before surgery.
CONCLUSION—The car driving population greatly benefited from cataract surgery in terms of subjectively improved visual function and distance estimation while driving. Functional visual problems while driving should be considered as an indication for cataract surgery. These findings also indicated that the second eye should be operated on, if necessary, to achieve optimal ability to estimate distance and give best possible road safety.

     

Is month of birth associated with cataract in later life?

BACKGROUND—It has been suggested that season of birth might influence the susceptibility to cataract in later life.
METHODS—This hypothesis was investigated using data pooled from two case-control studies carried out in Oxfordshire.
RESULTS/CONCLUSION—The results showed no relation between month or season of birth and cataract in later life in an English population.

Keywords: cataract; age; birth month     

Relation between postoperative blood-aqueous barrier damage and LOCS III cataract gradings following routine phacoemulsification surgery

AIM—To examine the relation between cataract density, the phacoemulsification energy required for its removal, and blood-aqueous barrier (BAB) damage on the first day after surgery.
METHODS—A prospective study recruiting patients with normal eyes apart from senile cataract. Preoperatively, visual acuity, anterior chamber laser flare, and cell values were measured using the Kowa laser flare meter, and the LOCS III grading of the cataract defined. The patients all underwent standardised phacoemulsification surgery through a superior scleral tunnel incision, with confirmed in the bag placement of a one piece PMMA IOL; all surgical complications were excluded. The phaco power delivered was recorded as the cumulative delivered energy, CDE. On day 1 visual acuity and laser flare and cell readings were taken.
RESULTS—101 patients were recruited and all completed the protocol. Older patients had a higher preoperative flare value (p=0.003); preoperative cell values were significantly related to nuclear opacity (p=0.021) and colour (p=0.011). Postoperative flare was related to preoperative flare (p=0.001) and nuclear colour (p=0.038). CDE was related to nuclear colour (p=0.031) and opacity (p=0.022), but not to aqueous flare.
CONCLUSIONS—Damage to BAB after routine phacoemulsification surgery is predicted by the preoperative flare values and the density of the cataract nucleus. The amount of phacoemulsification energy required to remove a cataractous lens is related to the density of the cataract but affects postoperative flare to a minimal degree. Other factors such as surgical technique are probably more important. Laser photometry is a useful tool for objectively assessing surgical technique.

     

Visual outcome after paediatric cataract surgery: is age a major factor?

AIMS—To determine functional results after unilateral and bilateral cataract surgery in children with different aphakic optical correction.
METHODS—In this retrospective study, we evaluated visual acuity and binocular vision in 107 children who underwent cataract surgery during the 10 year period from 1985 to 1995. Aphakia was corrected by an intracapsular intraocular lens (IOL), spectacles or contact lenses.
RESULTS—Mean visual acuity was >20/40 (<0.3 log MAR) with normal binocular vision in 58 children over 7 months of age operated on for bilateral cataracts. Pseudophakic eyes regained visual acuity >20/63 (<0.5 log MAR) more often (90%) than aphakic eyes (46%) (p<0.001). Binocular vision was also achieved more often after IOL implantation (p<0.001). Visual outcome of early bilateral cataracts was less satisfactory in children with abnormal foveolar function. For 49 children who had surgery for unilateral cataracts, prognosis was poor when surgery was performed before the age of 7 months. For cataract surgery in older children (7 months) mean visual acuities were better with IOL implantation (p<0.05).
CONCLUSION—Cataract surgery with unilateral and bilateral IOL implantation can provide a beneficial effect on final visual outcome in children who are operated on before abnormal foveolar function develops.

Keywords: binocular vision; intraocular lens; paediatric cataract; visual outcome     

Topical anaesthesia with oxybuprocaine versus sub-Tenon's infiltration with 2% lignocaine for small incision cataract surgery

AIMS—To determine whether topical anaesthesia in small incision self-sealing phacoemulsification cataract surgery provides comparable anaesthesia to sub-Tenon's infiltration.
METHODS—Thirty five patients undergoing small incision self-sealing phacoemulsification cataract surgery were allocated randomly to receive topical anaesthesia with 0.4% oxybuprocaine or sub-Tenon's infiltration with 2% lignocaine. Pain experienced during the operation was assessed by asking the patient to score on a visual analogue graphic pain score chart.
RESULTS—The median pain score for the topical group (3) was significantly higher than that of the sub-Tenon's group (0) (p = 0.004).
CONCLUSION—Sub-Tenon's infiltration is superior to topical anaesthesia in ensuring patient comfort during small incision scleral tunnel self-sealing phacoemulsification cataract surgery.

     

First report of congenital or infantile cataract in deranged proteoglycan metabolism with released xylose

AIM—To investigate the chemical pathology in the blood and lens, in cases of congenital or infantile cataract in children excreting predominantly non-reducing carbohydrates in urine.
METHODS—Urine samples from children with congenital or infantile cataract, and age and sex-matched controls, were analysed for (i) inherited errors of metabolism, (ii) paper chromatography of sugars, (iii) spectrophotometric assay of glycosaminoglycans (GAG), (iv) cetyl trimethyl ammonium bromide test, (v) electrophoresis using Alcian blue, (vi) ion exchange chromatography with IR 120 resin, and (vii) HPLC for xylose. Blood and lens material were also tested for GAG fragments and xylose. β Glucuronidase was assayed in lymphocytes and urine.
RESULTS—Of 220 children of both sexes below 12 years of age, with congenital or infantile cataract treated in Sankara Nethralaya, Madras, India, during a period of 2 years, 145 excreted fragments of GAG (heparan and chondroitin sulphates) in their urine. There was no such excretion among the control group of 50 children. The same was found accumulated in the blood and lenses of affected children. In addition, xylose was present in small amounts in the urine and blood and xylitol was present in the lens. There was a significant elevation in the activity of β glucuronidase in lymphocytes and urine, when compared with normals. All the above findings suggest deranged proteoglycan metabolism. As the urine contained mostly GAG fragments and very little xylose, Benedict's reagent was not reduced. This ruled out galactosaemia.
CONCLUSION—An increase of β glucuronidase activity might have caused extensive fragmentation of GAG with resultant accumulation in the blood and lens and excretion in urine. Small amounts of xylose may have come from xylose links between GAG and core protein of proteoglycans. Owing to their polyanionic nature, GAG fragments in the lens might abstract sodium, and with it water, thereby increasing the hydration of the lens. Excessive hydration and the osmotic effect of xylitol from xylose might cause cataract. While corneal clouding has been reported in inborn acid mucopolysaccharidosis, congenital or infantile cataract with deranged metabolism of proteoglycans (acid mucopolysaccharide-xylose-protein complex) is reported in children for the first time.

     

Variation in indications for cataract surgery in the United States, Denmark, Canada, and Spain: results from the International Cataract Surgery Outcomes Study

BACKGROUND/AIMS—International comparisons of clinical practice may help in assessing the magnitude and possible causes of variation in cross national healthcare utilisation. With this aim, the indications for cataract surgery in the United States, Denmark, the province of Manitoba (Canada), and the city of Barcelona (Spain) were compared.
METHODS—In a prospective multicentre study, patients scheduled for first eye cataract surgery and aged 50 years or older were enrolled consecutively. From the United States 766 patients were enrolled; from Denmark 291; from Manitoba 152; and from Barcelona 200. Indication for surgery was measured as preoperative visual status of patients enlisted for cataract surgery. Main variables were preoperative visual acuity in operative eye, the VF-14 score (an index of functional impairment in patients with cataract) and ocular comorbidity.
RESULTS—Mean visual acuity were 0.23 (USA), 0.17 (Denmark), 0.15 (Manitoba), and 0.07 (Barcelona) (p<0.001). When restricting the sample to eyes with normal retina and macula, no significant difference between United States and Denmark was observed (p>0.05). Mean VF-14 scores were 76 (USA), 76 (Denmark), 71 (Manitoba), and 64 (Barcelona) (p<0.001).
CONCLUSION—Similar indications for cataract surgery were found in the United States and Denmark. Significantly more restricted indications were observed in Manitoba and Barcelona. Possible explanations for the results are discussed, including differences in sociodemographic characteristics, access to care, surgeons' willingness to operate, and patient demand.

Keywords: cataract surgery; North America; Europe     

Effects of posterior chamber lens implantation on the endothelium of transplanted corneas

AIMS—The morphological changes of the corneal endothelium after posterior chamber lens implantation in the transplanted corneas were investigated.
METHODS—36 patients underwent extracapsular cataract extraction with posterior chamber lens implantation. Among these, penetrating keratoplasty had been performed in 18 patients before cataract surgery. The indications for penetrating keratoplasty in these cases included keratoconus, herpetic keratitis, and macula cornea. 18 cataract patients with normal corneas were also studied as controls. The central corneal endothelium in each subject was examined with a wide field specular microscope at a few days before and 3 months after cataract surgery.
RESULTS—Although the transplanted corneas showed lower endothelial cell densities, marked polymegethism, and pleomorphism in the baseline variables, the endothelial morphological changes in the transplanted corneas after posterior chamber lens implantation were comparable with those in the normal corneas. Also, there was no clinical evidence, especially, of corneal epithelial and/or endothelial rejections and corneal decompensation in all corneas.
CONCLUSION—Even though the transplanted corneas have a lower endothelial cell density and marked polymegethism, it is believed that cataract surgery does not induce corneal decompensation in cases where the peripheral recipient endothelium can be considered to have normal morphology.

     

Prevalence of blindness and cataract surgery in Nepal

BACKGROUND—A national eye care programme was launched in Nepal in the early 1980s. The impact of this programme on blindness and cataract surgery prevalence was evaluated in two geographic zones.
METHODS—People aged 45 years and older were sampled using a stratified cluster design. Within randomly selected clusters, door to door enumeration was followed by visual acuity measurement and eye examinations at conveniently located sites. The full survey was preceded by a pilot study where operational methods were refined and quality assurance measures carried out.
RESULTS—Of the 5112 enumerated individuals 90% were examined. Blindness, defined as presenting visual acuity less than 6/60 in both eyes, was found in 5.3% (95% CI 3.6, 6.8) of individuals examined, with cataract being the principal cause in at least one eye in 78% of cases. Considering both cataract operated and unoperated cataract blind cases, surgical coverage was approximately 42%.
CONCLUSION—The findings suggest that blindness prevalence may have decreased slightly from that estimated in a 1981 national survey, both overall and cataract related. Similarly, cataract surgical coverage may have increased somewhat. None of these changes, however, are at statistically significant levels. Accordingly, the blindness problem remains challengingly high.

Keywords: blindness prevalence, cataract blindness, aphakia/pseudophakia     

Do patients with age related maculopathy and cataract benefit from cataract surgery?

AIMS—To assess the benefits of cataract extraction in patients with age related maculopathy (ARM).
METHODS—1073 randomly selected cataract operations were reviewed and 99 cases of preoperatively recognised ARM were identified for investigation. Data relating to visual function were retrieved from case notes, and patient responses to a questionnaire were analysed.
RESULTS—98% had dry or unspecified ARM. Only 2% had exudative maculopathy. 81% of cases had an improvement in best distance acuity; mean change 0.44 logMAR (change of 6/36 to 6/12). 65% responded to the questionnaire; 67% felt that the operation had been worthwhile, 17% had mixed feelings, and 17% thought it not worthwhile.
CONCLUSION—This study, which is the first of its kind to be reported, shows a clear benefit from cataract surgery in the majority of patients with ARM. However, the prevalence of ARM in this study is lower than expected, suggesting that some patients with both ARM and cataract were not listed for surgery. The design of a prospective study to quantify the subjective and objective benefits of cataract surgery in these patients is outlined and predictors of successful outcome identified. This will promote the development of guidelines for the surgical management of this group of patients.

Keywords: age related maculopathy; cataract; cataract surgery; outcome assessment; questionnaire     

National survey of blindness and low vision in Lebanon

AIMS—To survey level of blindness and low vision in Lebanon.
METHODS—A population survey was undertaken in 10 148 individuals to measure the prevalence and identify the causes of blindness in Lebanon.
RESULTS—The prevalence of blindness was 0.6% and that of low vision 3.9%. The major causes of blindness were cataract (41.3%) and uncorrected large refractive error (12.6%).
CONCLUSION—Most causes of blindness in Lebanon can be controlled by various educational and medical programmes.

     

Pseudoexfoliation syndrome and secondary cataract

AIM/BACKGROUND—The pseudoexfoliation (PEX) syndrome is frequently associated with impairment of the blood-aqueous barrier. This study analysed if this might stimulate secondary cataract following cataract extraction.
METHODS—This historical cohort study included 197 eyes of 197 patients (99 with and 98 without PEX) that underwent extracapsular cataract extraction with posterior chamber lens implantation (PMMA optic) between 1985 and 1991. Secondary cataract was defined as opacification of the axial posterior capsule and decrease of visual acuity by two or more lines. Mean follow up was 23.8 months. For statistical analysis, the Kaplan-Meier method and multivariate Cox regression analysis were used.
RESULTS—Secondary cataract was observed within 24 months in 35% (SD 7%) of all eyes, and was significantly more frequent in eyes with PEX (45 (11)%) than in eyes without PEX (24 (9)%, p<0.03). Eyes with diabetes mellitus (n=32) showed a significantly lower frequency of secondary cataract (11 (11)%) than eyes without diabetes mellitus (39 (8)%, p<0.01). The influences of sex, open angle glaucoma, type of cataract, surgeon, positioning of IOL, and phacoemulsification versus nuclear expression on secondary cataract did not reach statistical significance.
CONCLUSION—The higher frequency of secondary cataract could be considered as another potential complication of cataract surgery in eyes with PEX.

     

Cataract progression in India

AIMS—The study was undertaken to test the feasibility of using the LOCS III cataract grading scale in the field and to determine the rate of cataract progression over a 1 year period of time.
METHODS—For 150 subjects between the ages of 33 and 55 who attended the refraction clinic at Aravind Eye Hospital in Madurai, India, lens abnormalities were graded at the slit lamp using the LOCS III scale. One year later, 99 of the subjects were re-evaluated by the same methodology to assess the amount of lens change.
RESULTS—Interrater reliability was high. A change of 0.5 or more in lens colour, cortical, nuclear, or posterior subcapsular cataract was observed in at least one eye of 54% of the subjects.
CONCLUSION—The LOCS III grading scale is a feasible method for measuring lens changes in the field with the slit lamp. Cataract progression in India is rapid enough to permit intervention studies to be performed with relatively small numbers of subjects over a short period of time (that is, 600 subjects for 2 years).

     

Cadmium, lead and copper concentrations in normal and senile cataractous human lenses

Cadmium, lead and copper concentrations were measured in normal and cataractous human lenses by atomic absorption spectrophotometry. The concentrations of all three elements were relatively higher in cataractous lenses compared with normals, and the ratios of cataract/normal concentrations were in the order Pb greater than Cd greater than Cu. The concentration of these trace elements also varied according to lense age. It is likely that the major source of cadmium is tobacco smoke while that of lead is the exhaust gases of motor cars.     

Peroperative microbial contamination of anterior chamber aspirates during extracapsular cataract extraction and phacoemulsification

BACKGROUND—The normal conjunctival flora is one of the main sources of intraocular contamination during cataract surgery. The theory that the positive anterior chamber (AC) pressure during phacoemulsification (phaco), and the smaller wound utilised, might reduce the rate of contamination was studied.
METHODS—The peroperative AC aspirates of 210 consecutive patients undergoing cataract surgery were assessed. In group 1, 100 patients underwent a standard extracapsular cataract extraction (ECCE). In group 2, 110 patients underwent phacoemulsification of the crystalline lens through a scleral tunnel. AC aspirates from the Simcoe irrigation/aspiration cannula (group 1) and phaco probe (group 2) were collected and microbiological studies performed after direct and enrichment cultures.
RESULTS—There were 29 (29%) positives in the ECCE group compared with 22 (20%) positive cultures from AC aspirates in the phaco group. Coagulase negative staphylococcus (CNS) was the commonest contaminant in both groups.
CONCLUSION—Although there was a higher rate of AC contamination during ECCE, the difference was not statistically significant (p> 0.10, χ²=2.31).