Modern surgery of cataracts

Surgery of cataract has a history of almost 250 years. The first 150 years were in the sign of extracapsular extracion. The subsequent 70 years were devoted to the development and improvement of the technique of intracapsular extraction and the last more than 20 years are a return to extracapsular extraction. This is due in particular to the development of microsurgery. "Modern surgery of cataract" is thus extracapsular extraction at a microsurgical level, in indicated cases associated also with implantation of an intraocular lens. The author analyzes recent aspects of indication for operation, preoperative examination techniques, preoperative preparation of the patient, anaesthesia, the operation proper, correction of aphakia, and postoperative care. In the author's opinion the future of microsurgery of cataract will involve improvement and wider use of phakoemulsification and laser systems as well as new models and materials for artificial lenses. It is no longer an unreal dream to make through a minimal paracentesis a microincision of the capsule, remove the nucleus and mass intracapsularity and replace them by injection of a transparent, artificial gel.     

Corticosteroid-induced cataracts

The association linking corticosteroid therapy with the development of posterior subcapsular cataracts has been well documented. These drugs are widely used therapeutically, principally to capitalize on their ability to inhibit inflammatory responses. The literature on corticosteroid-induced posterior subcapsular cataracts is reviewed here. Data from the previously published series and individual lens susceptibility to corticoids do not allow the establishment of a direct factor relating cataract formation to corticosteroid dose and the duration of therapy; however, significant progress has been made in elucidating the mechanism by which corticoids bring about the development of these opacities. Exploration into the development of these lesions has shed light on the similarities these opacities share with other cataracts, especially with regard to location and pathogenesis.     

Pediatric cataracts

The treatment of an infant or child with a cataract requires a different decision process and surgical technique compared with the treatment of an adult with a cataract. The pediatric cataract literature of the past year reminds the reader that the indications for surgery and preoperative management of the pediatric cataract patient are different, that the response to surgery is different, necessitating the use of new techniques for surgery, and that complications after surgery are more common. These differences are caused by the anatomy of the pediatric eye and the susceptibility of the developing visual system to amblyopia. The literature of the past year supports with laboratory study and clinical reports the current trend toward more common use of intraocular lenses in children.     

Childhood cataracts

Objective : The aim of this study was to determine the surgical outcome of childhood cataracts. Method : Between 1990 and 1997, 137 patients less than 10 years of age (181 eyes) underwent cataract surgery at the Royal Alexandra Hospital for Children/New Children's Hospital. Data were collected retrospectively from medical records and supplemented with data from referring ophthalmologists. Results : In the majority of patients (53.0%), the cause of cataract was unknown. Sixty‐two patients (45.3%) had bilateral and 75 patients (54.7%) had unilateral cataracts. In 84 patients (107 eyes; 59.1%), the onset of visually significant cataract was estimated to be before the age of 2 years. Reliable postoperative visual acuity (VA) was obtained in 150 eyes from 116 patients. The mean LogMAR VA was 0.71 ± 0.55 in bilateral cataracts and 1.17 ± 0.68 in unilateral cataracts. Visual acuity was poor (LogMAR VA > 1.0) in 71.8% of unilateral cataracts (compared to 27.9% in bilateral cataracts, P < 0.0001), and in 64.9% when onset was less than 2 years (compared to 22.4% in later onset cataract, P < 0.0001). Posterior capsular opacity requiring laser or surgical removal was noted in 40 patients (44 eyes; 24.4%). Other complications included raised intraocular pressure in six patients (seven eyes; 3.7%), displaced intraocular lens or iris capture in 11 patients (12 eyes; 6.6%), ectopic pupil in five patients (five eyes; 2.7%), and severe inflammation in eight patients (12 eyes; 6.6%). There was cosmetically significant esotropia or exotropia in 24 patients (23 eyes; 12.7%). Conclusion : The prognosis for vision was significantly poorer in unilateral and earlier onset cataract. The importance of early diagnosis, prompt treatment and vigilant postoperative follow up in this subgroup cannot be over‐emphasized.     

Pediatric cataracts

Posterior chamber intraocular lenses are a well-accepted treatment of aphakia in children 2 years of age and older, with many now considering them as the treatment of choice. Infants, however, are usually treated with contact lens, rather than intraocular lens implantation, as the infant eye undergoes significant axial elongation. The use of intraocular lenses in children with cataracts associated with juvenile rheumatoid arthritis remains controversial, but a recent article [9] describes good results in these patients, who historically have a poor prognosis. The management of amblyopia associated with unilateral congenital cataracts is evolving. In the 1970s and 1980s, full-time occlusion of the sound eye was advocated for infants with unilateral congenital cataracts. It was also taught that binocular fusion was impossible to obtain, and children with unilateral cataracts inevitably develop strabismus. Recent studies have shown that part-time occlusion may in fact yield better results, allowing the development of binocular vision and stereopsis and reducing the incidence of strabismus.     

Infantile cataracts

Cataracts are one of the most treatable causes of visual impairment during infancy. Recentepidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.     

Pediatric cataracts

Over the past year, major advances have occurred in our understanding of the surgical management of pediatric cataracts. New insights concerning the response of the pediatric eye to intraocular lens implantation coupled with improved surgical techniques are expanding the indications and reducing the complications of intraocular lens implantation in children. Additionally, new progress has been made in identifying the risk factors for the development of pediatric cataracts and the etiologies of associated complications.     

Allopurinol and cataracts

We conducted a two-part study to determine whether any positive association between the use of allopurinol and the development of cataracts could be demonstrated. Study 1 included 251 Boston-area patients hospitalized for cataract and 753 matched controls. Two cataract patients were regular allopurinol users as compared with six control patients. The relative risk for cataract comparing allopurinol users with nonusers was 1.0 (95% exact confidence interval 0.14, 4.7). Study 2 included 389 patients from the Puget Sound, Washington, area who were hospitalized for cataract surgery during a five-year period (551,543 person-years). The rate of hospitalization for cataract in patients 30 to 49 years old was 0/992 person-years for allopurinol users and 78/366,960 (2.1 per 10(4)) person-years for nonusers. The rate of hospitalization for cataract in patients 50 to 64 years old was 3/2,270 (13.2 per 10(4)) person-years for allopurinol users and 308/184,583 (16.7 per 10(4)) person-years for nonusers.     

Burgdorf and cataracts

This contribution recounts the life of Johann Heinrich Jung, also known as Stilling: his curriculum vitae, method of cataract surgery, trips to Switzerland, the cataract operation he performed in Burgdorf in 1802.     

Grading infantile cataracts

PURPOSE: To introduce and describe two methods of grading the severity of infantile cataracts, and thereby propose a useful clinical guide for early surgical intervention. METHODS: Thirty-three subjects, aged 1 week to 8 years, participated in the study. Twenty-two were evaluated soon after birth (1 week), and 11 in childhood (3-8 years). All had isolated infantile cataracts, of which 16 were bilateral and 17 unilateral. Nine cataract types were examined; nuclear (n = 9), lamellar (n = 9), posterior lenticonus (n = 4), persistent hyperplastic primary vitreous (n = 4), posterior polar (n = 3) and single cases of total, cortical, sutural and anterior polar. Grading the infantile cataracts was performed subjectively based on the cataract morphology, density and position using an 11-point (0-10) ordinal scale. Objective measures of the cataracts were performed by scanning and then digitising photo-slit lamp images to provide cataract intensity profiles. Subjects without cataracts acted as controls. RESULTS: Subjective gradings of 0 and 10 were assigned to the clear, cataract-free lens and the total cataract, respectively. Fixed grades of 1 (anterior polar, sutural) and 6 (posterior polar) were assigned to the three remaining cataracts with static morphologies. The five cataracts which were all progressive were given grading ranges, reflecting the initial and likely final morphological states. Objective measures were found to be valuable in indicating the exact position and relative density of the cataract, as well as accurately defining boundaries. CONCLUSIONS: The magnitude and severity of infantile cataracts can be usefully characterised by an 11-point ordinal subjective grading scale. Although subjective grading alone is satisfactory, it can be greatly assisted by objective measures, particularly in the documentation of cataract progression. Cataracts assigned grades 1-4 were considered minor obstructions to vision and therefore not candidates for early surgery. Cataracts graded 5 and above were considered major visual defects, and ideally should be removed early in life.