Managing Pediatric Cataract Patients - The Whole Story: Aphakic Contact Lenses in Children - Techniques and Challenges

Infantile cataract is one of the major causes of visual impairment in children. This article will discuss some of the techniques, challenges, complications, and compliance issues with aphakic contact lenses.

Strabismus surgery outcomes in the Infant Aphakia Treatment Study (IATS) at age 5 years

PURPOSE

To report strabismus surgery frequency and outcomes after monocular infantile cataract surgery with or without IOL implantation.

METHODS

The Infant Aphakia Treatment Study (IATS) is a randomized, multicenter clinical trial comparing treatment of aphakia with a primary IOL or contact lens in 114 infants with a unilateral congenital cataract. This report is a secondary outcome analysis of ocular motor data from IATS patients who underwent strabismus surgery prior to age 5 years.

RESULTS

Strabismus surgery was performed in 45 (39%) patients (contact lens group [CL], 37%; IOL group, 42% [P = 0.70]). The indications for strabismus surgery were esotropia (62%), exotropia (33%), and hypertropia (4%). Infants who underwent cataract surgery at a younger age were less likely to undergo strabismus surgery (28-48 days, 12/50 [24%]; 49-210 days, 33/64 [52%]; P = 0.0037). Of the 42 patients who underwent strabismus surgery, 14 (33%) had a postoperative distance alignment within 8^Δ of orthotropia at age 5 years. The 5-year visual acuity of children with strabismus was the same whether or not strabismus surgery had been performed (1.10 logMAR with surgery vs 1.00 without [P = 0.71]).

CONCLUSIONS

In this study cohort, cataract surgery performed in the first 6 weeks of life was associated with a reduced frequency of strabismus surgery. Strabismus surgery outcomes in this population are guarded. Surgical improvement of strabismus does not appear to influence long-term visual acuity.

Comparison of the rate of refractive growth in aphakic eyes versus pseudophakic eyes in the Infant Aphakia Treatment Study

PURPOSE

To compare the rate of refractive growth (RRG) between aphakic eyes and pseudophakic eyes in the Infant Aphakia Treatment Study (IATS).

SETTING

Twelve clinical sites across the United States.

DESIGN

Randomized clinical trial.

METHODS

Patients randomized to unilateral cataract extraction with contact lens correction versus intraocular lens (IOL) implantation in the IATS had their rate of refractive growth (RRG3) calculated based on the change in refraction from the 1-month postoperative examination to age 5 years. The RRG3 is a logarithmic formula designed to calculate the RRG in children. Two-group t tests were used to compare the mean refractive growth between the contact lens group and IOL group and outcomes based on age at surgery and visual acuity.

RESULTS

Longitudinal refractive data were studied for 108 of 114 patients enrolled in the IATS (contact lens group, n = 54; IOL group, n = 54). The mean RRG3 was similar in the contact lens group (-18.0 diopter [D] ± 11.0 [SD]) and the IOL group (-19.0 ± 9.0 D) (P = .49). The RRG3 value was not correlated with age at cataract surgery, glaucoma status, or visual outcome in the IOL group. In the aphakia group, only visual outcome was correlated with refractive growth (P = .01).

CONCLUSIONS

Infants' eyes had a similar rate of refractive growth after unilateral cataract surgery whether or not an IOL was implanted. A worse visual outcome was associated with a higher RRG in aphakic, but not pseudophakic, eyes.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Gravitational pseudoaccommodation in patients with aphakic iris-claw intraocular lenses

PURPOSE

To assess whether iris-claw intraocular lenses (IOLs) undergo gravitation-dependent changes in position and refraction.

SETTING

Tertiary referral center, Bern, Switzerland.

DESIGN

Observational case study.

METHODS

Patients with a history of pars plana vitrectomy and IOL exchange with implantation of an aphakic iris-claw IOL (Artisan) were included in this study. Objective refraction was obtained with a handheld autorefractometer, and the IOL position was measured by ultrasound biomicroscopy with the patient prone, sitting, and supine.

RESULTS

Twenty-one eyes of 19 patients with retropupilary IOLs (13) or prepupillary IOLs (8) were included. The mean spherical equivalent (SE) in the sitting position was -0.81 diopter (D) ± 0.95 (SD), and the mean distance from the endothelium to the anterior edge of the IOL was 3.35 ± 0.72 mm. The mean SE in the supine position was -0.61 ± 1.28 D, whereas the mean SE in the prone position was -1.34 ± 1.17 D (P = .0030). The IOL position changed from 3.50 mm in the supine position to 3.06 mm in the prone position (P < .0001).

CONCLUSIONS

The aphakic iris-claw IOL was subject to significant movement related to gravity. The change in the refractive effect suggests that there is a degree of pseudoaccommodation caused by the forward shift of the aphakic IOL in the face-down position.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

[Visual acuity and binocular vision in children with pseudophakia]

PURPOSE

To evaluate the results of cataract surgery in children with IOL implantation.

MATERIALS AND METHODS

Our research involved 106 children (156 eyes) with congenital and traumatic cataract, in age from 18 months to 18 years, who underwent cataract surgery with intraocular lens implantation. We evaluated visual acuity for far vision and binocular vision after surgery.

RESULTS

Visual acuity over 0.5 in unilateral congenital cataract was found in 27.25%, in traumatic cataract in 73%, whereas in bilateral congenital cataract visual acuity over 0.5 we received in 75% of operated children. Full binocular vision was obtained in children with good visual acuity (0.5 and more), with appropriate alignment of the eyes: 13.1% in unilateral congenital cataract, 45.4% in traumatic cataract and 55% in congenital bilateral cataract.

CONCLUSIONS

Cataract surgery with intraocular lens implantation results in increase of visual acuity and in achievement binocular vision, if surgery is carried out in the early period, after it had been diagnosed.

[Senile cataract and strabismus]

PURPOSE

To evaluate whether the periodical sensory deprivation due to senile cataract and leading to strabismus, can result in the loss of binocularity.

MATERIAL AND METHODS

We examined 26 patients with dense cataract in one or both eyes and with strabismus that appeared after development of cataract in the absence of any other ophthalmological defect. All the patients had cataract extracted in one or both eyes by the method of phacoemulsification with implantation of PC IOL. Examination included: measurement of deviation of the eye for distance before and after surgery, visual acuity before and after treatment, stereopsis on Titmus test for distance.

RESULTS

All patients had exodeviation of -10 to -40 degrees before surgery. Visual acuity before treatment was low: maximum was 0.1. 81% of patients had VA on the level of hand movement or worse. Six months after treatment 19 patients were orthotopic, and in 7 patients the deviating eye changed (these patients had cataract in both eyes). 2 of these patients had cataract surgery and regained orthotopic position. Among 21 orthotopic patients after surgery, stereopsis was present in 18 (86%).

CONCLUSIONS

Sensory deprivation due to dense cataract can cause exodeviation. In most cases it does not lead to loss of binocularity.

The aetiology in paediatric aphakic glaucoma

PURPOSE

To investigate the causes of glaucoma in children following removal of cataracts.

METHODS

In total, 24 patients (37 eyes) with uncomplicated congenital cataracts who developed glaucoma following cataract removal were studied retrospectively. Cataract morphology, surgical technique, postoperative complications, time to glaucoma onset, gonioscopic findings, the presence of microcornea, and the histopathologic characteristics of the filtration angle in one case were the studied parameters.

RESULTS

We found a bimodal onset of glaucoma. Early-onset glaucoma occurred at a mean age of 6 months in 15 eyes and delayed-onset glaucoma at a mean age of 12 years in 22 eyes. Early-onset glaucoma was significantly (P=0.018) more likely to be due to angle closure. With delayed-onset glaucoma, the filtration angle is open in 86% of eyes and significantly (P=0.006) more eyes in the delayed-onset group had microcornea.

CONCLUSIONS

Performing cataract surgery very early in life in microphthalmic eyes and leaving residual lens material increases the risk for glaucoma. We recommend a prophylactic iridectomy in eyes at risk for pupillary block. Eyes with delayed-onset glaucoma have open filtration angles but with findings consistent with incomplete development of filtration structures. Early age at cataract extraction and microcornea are risk factors for delayed-onset glaucoma.

The efficacy of neodymium: YAG laser iridotomy in the treatment of closed peripheral iridotomies in silicone-oil-filled aphakic eyes

Eighteen patients had a surgical inferior peripheral iridotomy performed to prevent pupil block and silicone oil anterior chamber prolapse. The occlusion of an iridotomy was treated by neodymium: YAG laser therapy and this form of treatment was successful only in 4 cases (22%). The reopening of occluded iridotomies is best performed by surgery as opposed to laser treatment.

Extended wear soft contact lenses induce corneal epithelial changes

The purpose of this study was to determine the corneal epithelial alterations induced by various types of contact lenses. By employing the specular microscope, the corneal epithelia of 60 patients who had worn contact lenses for more than 1 year were re-examined along with 15 myopic controls. The morphological changes in aphakic patients who changed from extended wear soft to extended wear rigid gas permeable lenses were also studied. The mean cell area of the corneal epithelium was 621.5 (SD 92.5) microns 2 for daily wear rigid gas permeable lenses (n = 15), 645.8 (98.1) microns 2 for daily wear soft lenses (n = 15), and 634.7 (88.6) microns 2 for extended wear rigid gas permeable lenses (n = 15), none of which differed significantly from the control value of 610.5 (98.1) microns 2. Only the extended wear soft lens group (n = 15) showed significantly enlarged epithelia (806.1 (50.1) microns 2, p < 0.01 versus the other groups). The epithelium partially returned to normal after changing from extended wear soft lenses to extended wear rigid gas permeable ones. The corneal epithelium showed increased cell area only with extended wear soft contact lenses which are known to pose a risk for corneal infection.

[Effects of the duration of cataract extraction and eyeglass wear in patients with aphakia on the development of changes in the macular area]

Forty-eight patients with aphakia were examined to elucidate the effect of cataract extraction duration on subsequent development of Irwin-Hass syndrome. A total of 229 patients were examined 6 months and more after cataract extraction to find out whether sun light could induce development of dystrophic changes in the central retina in aphakia. The results indicate that operation duration of more than an hour increased the risk of subsequent development of Irwin-Hass syndrome. Aphakia patients wearing no eyeglasses or contact lenses or intraocular lenses may develop maculodystrophies, probably due to the injurious effect of sun rays on the retina.

Cataract extraction in uveitis: comparison of aphakia and posterior chamber lens implantation

We reviewed the charts of 39 patients (45 eyes) with uveitis who underwent cataract extraction (intracapsular or extracapsular) with or without implantation of a posterior chamber intraocular lens (IOL) at the Royal Victoria Hospital, Montreal, between 1981 and 1990. The nine eyes with Fuchs' iridocyclitis in which an IOL was implanted had good visual results and few postoperative complications. The 18 eyes with uveitis other than Fuchs' iridocyclitis that received an IOL did not show a greater risk of postoperative complications than those left aphakic (n = 17), and the postoperative visual acuity was comparable to that of the aphakic eyes. Although the numbers are small, we conclude that the presence of uveitis does not automatically exclude posterior chamber pseudophakia.

Superficial punctate keratopathy and bacterial growth in patients with unilateral aphakia using extended-wear soft contact lenses

We prospectively examined corneal conditions and bacterial growth in 77 individuals with unilateral aphakia who were using extended-wear soft contact lenses. The ratios of positive bacterial growth (70.6-79.4%) from 34 patients with superficial punctate keratopathy were significantly higher than those (41.9-46.5%) from the 43 subjects with normal corneas. Bacterial growth was found frequently in patients with superficial punctate keratopathy who were older than 80 years and in those using soft contact lenses for more than 22 days. Several kinds of bacteria grew from the specimens. Among the most common were Staphylococcus epidermidis and Corynebacterium species. Pseudomonas aeruginosa grew from patients with superficial punctate keratopathy who were using extended-wear soft contact lenses.

[Prognostication of results in correction of aphakia by lamellar refractive keratoplasty]

The authors analyze the possibility of predicting the results of aphakia correction by interlamellar refraction keratoplasty from one of the eye parameters measured before surgery, the anterior corneal surface radius. The prognosis efficacy has improved by 10% vs. the prediction from the mean value; this is insufficient for practical application of the method. The prediction may be made more accurate if the number of the eye parameters measured before surgery is increased and the measurements are more precise.

Prevention and management of delayed suprachoroidal hemorrhage after filtration surgery

We report two new cases of massive delayed nonexpulsive suprachoroidal hemorrhage (DNSH) following a filtering operation in the aphakic eyes of elderly patients with glaucoma. A timely surgical drainage resulted in full recovery of preoperative visual acuity in both of our patients. As we combine our cases with a series of 18 similar cases of others in the literature, the following conclusions emerge. Limited DNSH does not require surgical intervention for a favorable visual outcome. Massive DNSH, however, requires timely and appropriate surgical intervention to achieve a favorable visual outcome and to avoid persistent hypotony. The most effective surgical intervention is drainage of the suprachoroidal hemorrhage and re-formation of the anterior chamber, but without concomitant vitrectomy. In both limited and massive DNSH, the final visual outcome is not determined by the worst vision at the time of DNSH. Some of the known and suspected risk factors of DNSH following filtering surgery are old age, aphakia, postoperative hypotony, a history of vitreous manipulation or complication, general anesthesia, increased venous pressure, use of fluorouracil, and high myopia. In view of these risk factors, we recommend several preventive measures for decreasing the incidence of DNSH following filtering surgery.

The Lincoff temporary balloon buckle

The Lincoff temporary balloon buckle is an equally effective alternative to more conventional techniques in the management of selected retinal detachments. We used this technique in the management of 45 selected primary retinal detachments operated on since Nov. 22, 1980. Initial complete retinal flattening was achieved in 42 eyes (93%). Two of the three eyes that initially did not show complete flattening ultimately went on to do well without further surgery. Redetachment occurred in three of the five aphakic eyes (60%) and in four of the 36 phakic eyes (11%). None of the retinas in the four eyes with intraocular lenses redetached. Conventional scleral buckling techniques were used in the one case of initial failure and in the seven cases of redetachment for a final success rate of 98% after an average follow-up of 13 months.

Pulsed laser damage thresholds and laser treatment energy parameters, in vivo, of human aphakic intraocular membranes

Energy and power density damage thresholds were determined for the perforation of human aphakic pupillary membranes and intraocular lens implants, in vivo, at the focal point of Neodymium-YAG ophthalmic laser systems, at 1,064 nm, which produced Q-switched nanosecond pulses (TEMoo, pulse duration; 20 ns) and mode-locked pulse trains (TEMoo, 9-11 pulses, pulse duration; 30 ps, entire pulse train delivered in 50-70 ns). Pulse energies bracketing the damage thresholds and focal diameter were tabulated. The energy density and power density thresholds for perforation of the pupillary membranes (hereafter referred to as perforation threshold) were slightly lower and power density damage thresholds higher for shorter duration pulses, eg--66 J/cm2 (2,200 GW/cm2) with the picosecond pulse trains vs 80 J/cm2 (2.7 GW/cm2) with the nanosecond pulses and were similar in pseudophakics and aphakics; 78 J/cm2 for pseudophakics vs 83 J/cm2 aphakics, both treated with single nanosecond Nd-YAG pulses, and 68 J/cm2 for pseudophakic vs 66 J/cm2 for aphakic patients treated with picosecond Nd-YAG laser pulse trains. The number of laser pulses and pulse energies required for successful discussion of the pupillary membranes depended not only on the pulse parameters but also on the characteristics of the membrane, such as thickness, nonuniformity, capsular haze, or capsular haze combined with fibrosis.

[Equivalency of different methods of measuring lens power]

Mathematical error analysis shows that the prognosis of IOL powers on the basis of theoretical optical formulas for calculating lens power is no more accurate than the regression (SRK) formula. The minimum error in a recommended lens power is at present between +/- 0.6 and +/- 1.0 D. As a result of this range of error there is a range of equivalence of the two formulas, and the vast majority of cataract patients (85%) are within this range. However, in hyperopic eyes the SRK formula is clearly superior to the theoretical optical formulas for a clinically useful prognosis.

Pharmacologic therapy of aphakic and pseudophakic cystoid macular edema. 1985 update

Major advances in the pharmacologic therapy of aphakic cystoid macular edema (ACME) have not occurred since 1982. Topical nonsteroidal anti-inflammatory agents are still not commercially available for ocular therapy. Topical indomethacin remains the one agent which has been proven to be of prophylactic value for angiographic aphakic cystoid macular edema although other non-steroidal agents may also work. The therapeutic value of these compounds for established ACME remains uncertain. No prospective randomized prophylactic or therapeutic trials of either topical or systemic corticosteroids have been performed.

Coumadin related spontaneous hyphemas in patients with iris fixated pseudophakos

Spontaneous hyphemas in iris supported intraocular lenses are considerably more likely to occur in patients on systemic Coumadin therapy. Five cases are presented in which hyphemas appear to be related to Coumadin treatment.

The effect of retrobulbar epinephrine injection on ocular and optic nerve blood flow

The effect of retrobulbar epinephrine administration on ocular and optic nerve blood flow was studied in phakic and aphakic rabbit eyes using a radioactive microsphere (85Sr) technique. One hour before blood flow determination, 10 microliter of a 0.2% (base) epinephrine bitartrate solution was administered to the right eye of each experimental rabbit by the retrobulbar route. For control rabbits, 10 microliter of saline was injected retrobubarly. Blood flow measurements were determined for the iris, scrap[ed ciliary processes, choroid, retina, and optic nerve. Neither optic nerve nor ocular blood flow was altered by this dose which is approximately the dose used in retrobulbar injections in humans.

Tear analysis in contact lens wearers

Tear analysis in contact lens wearers was compared with tear analysis in aphakics without contact lens wear and normal phakic patients. Subjects were divided into five groups: group 1, aphakic without contact lens; group 2, phakic with daily-wear hard contact lens; group 3, phakic with daily-wear soft contact lens; group 4, phakic with extended-wear soft contact lens; and group 5, aphakic with extended-wear soft contact lens. The experimental groups were compared with age- and sex-matched control groups for statistical analysis of tear variables by means of the Student's t-test. The variables measured were tear osmolarity, tear albumin, and lysozyme and lactoferrin concentrations in basal and reflex tears. Highly significant elevations of tear osmolarity were found in aphakic subjects without contact lenses. Less significant differences in tear osmolarity were found in phakic subjects with hard daily-wear lenses or with extended-wear soft lenses. Tear albumin, lysozyme, and lactoferrin in basal and reflex tears were not significantly different in the different groups of contact lens wearers or in the group of aphakic subjects without contact lenses compared with their control groups. Individual variations in tear albumin, lysozyme, and lactoferrin appeared to be responsible for the inability to demonstrate significant differences in tear composition in association with the wearing of different types of contact lenses. Older and aphakic patients demonstrated a tendency to have increased concentrations of proteins in the tears compared with younger, phakic contact lens wearers and normal controls without contact lenses.

Corneal grafts for endothelial decompensation: the influence of intraocular lenses on corneal graft survival

Re-examination of the fate of 136 corneal grafts for bullous keratopathy (secondary endothelial decompensation) revealed a decreased, but not significant, graft survival of those grafts compared to the total of 572 grafts in patients with a diagnosis other than bullous keratopathy, as well as a decreased graft survival when compared to the survival of the grafts for Fuchs dystrophy (primary endothelial decompensation). A statistically significant decreased graft survival (P = 0.015) was observed when corneal grafts performed in pseudophakic eyes with secondary endothelial decompensation were compared to those performed in aphakic eyes with secondary endothelial decompensation. An immunological explanation for this difference was not detected. The influence of an intraocular lens on corneal corneal graft survival was analyzed. Indications for removing or retaining the intraocular lens at the time of graft surgery are reported.

Unilateral pseudophakia and extended-wear aphakic contact lenses. A comparative study in a single patient population

Twenty-nine patients who were pseudophakic in one eye and wearing a Permalens in the other eye were evaluated. Pseudophakic correction provided the patient with good, stable visual acuity, minimal risks, and an excellent long-term prognosis. Permalens aphakic correction also provided the patient with good, but fluctuating visual acuity. Risks such as deposit formation, tight lens syndrome, and corneal infections were not infrequently associated with the Permalens, and Permalens patients were also faced with the recurring cost of lens replacement. While both modalities of aphakic visual rehabilitation are acceptable, pseudophakia appears to provide the patient with better visual acuity, fewer risks, and lower financial costs in the long run.

Ultraviolet-absorbing pseudophakos: an efficacy study

The use of intraocular lenses (IOLs) to replace cataractous lenses has raised question of possible retinal damage due to exposure to ultraviolet (UV) radiation. Three groups of cynomolgus monkeys underwent cataract operations and either received normal UV-transparent IOLS or UV-opaque IOLs, or were left aphakic. All eyes were later exposed to UV light for varying periods of time. Exposure to UV light produced severe retinal lesions. In aphakic eyes and those with normal IOLs lengthy exposure to low levels of UV light produced lesions similar to those seen after brief, very intense UV radiation. Eyes with UV-opaque IOLs displayed no such lesions. Our results indicate that clinicians should consider the use of UV-opaque IOLs.

A mirror for self-examination by a patient with an aphakic eye

A mirror with a radius of curvature of 211.5 mm permits a patient who has undergone cataract surgery to examine his own aphakic eye without corrective lenses. A slight adjustment of the eye-to-mirror distance also permits examination of a normal eye, a hyperopic eye, and a presbyopic eye requiring a plus lens correction. The mirror can be used to monitor postoperative status and the course of a disease, and for inserting and removing contact lenses.

Good visual function after neonatal surgery for congenital monocular cataracts

We treated eight neonates who had total, monocular, congenital cataracts with surgery, occlusion, and contact lenses. Visual results in all eight patients were good. In five patients visual acuities improved to 6/9 (20/30) or better in the aphakic eye. In three patients visual acuities improved to 6/24 (20/80) or better. Problems with contact lenses probably accounted for the poorer results in two of these three patients. Binocularity was not demonstrated in any of our patients.

Prolonged wear soft contact lenses

Of 78 patients eligible for prolonged wear contact lenses, 50 (65%) were successfully fitted and followed for four months to four years. The most serious complication was peripheral corneal ulceration, occurring in 5 (10%) patients. None of these patients suffered permanent visual loss. The fitting of prolonged wear lenses required six or seven office visits during the first year and at least one lens per eye during the first year, for uncomplicated cases. In difficult cases the number of office visits and the number of replacement lenses increased significantly. In terms of the number of office visits and replacement lenses, the soft contact lens compares unfavorably with the intraocular lens. It is our feeling that the prolonged wear soft contact lens should be used when a lens implant is contraindicated or as an alternative to secondary lens implantation.

Transconjunctival buckling for retinal detachment

A specially designed ring indentator for transconjunctival buckling of retinal detachments is described. The experience on the first 15 patients treated is reported.