Thakur J, Reddy H, Wilson Jr ME, Paudyal G, Gurung R, Thapa S, Tabin G, Ruit S,
J Cataract Refract Surg 2004; 30:1629-35

The World Health Organization's (WHO) global initiative for the elimination of avoidable blindness by the year 2020' has identified the control of childhood blindness as a priority. Cataract remains one of the most important causes of avoidable blindness in children. Worldwide, an estimated 200 000 children are currently blind from cataract, and every year 20 000 to 40 000 neonates are born with congenital cataract. The burden of illness disproportionately affects the developing world, where the prevalence of cataract blindness is 10 times higher than in developed countries.

Pediatric cataract takes an enormous toll on developing countries in the form of human morbidity, economic loss, and social burden. Many infants with debilitating cataracts do not survive childhood. For those who do, the long-term burden of disability is tremendous. A child who goes blind today is likely to live until 2050. Accordingly, restoring this child’s sight may be equivalent to restoring the sight of 10 elderly adults in terms of “blind years” avoided, gained productivity, and overall savings to society.

The purpose of this study was to describe the first pediatric cataract surgery case series report from Nepal.
This study comprised a consecutive series of 112 eyes of 85 children having cataract surgery with intraocular lens (IOL) implantation. General anesthesia of ketamine combined with peribulbar block was used in all patients. Patients' demographics, cataract type and presenting symptoms, surgical intervention, pre-operative and postoperative visual acuities, and follow-up clinical examinations were recorded.

Seventy-three eyes (65.2%) of 53 patients had extracapsular cataract extraction with posterior capsulotomy, anterior vitrectomy, and posterior chamber IOL implantation (ECCE+PCAP+AV+PCIOL), and 39 eyes (34.8%) of 32 patients had cataract extraction and IOL implantation with an intact posterior capsule (ECCE+PCIOL). Of all patients, the mean age at surgery was 6.2 years ± 4.3 (SD). The median age in the ECCE+PCAP+AV+PCIOL group was 4.7 years and in the ECCE+PCIOL group, 11.0 years. The mean follow-up was 5.4 ± 5.3 months. The most common postoperative complication in the ECCE+PCIOL group was visual axis/posterior capsule opacification, which was seen in 18 eyes (46.2%) compared to 4 eyes (5.5%) in the ECCE+PCAP+AV+PCIOL group. Visual acuity improved with surgery in both groups. The leading cause of poor outcomes was deprivation amblyopia. There were no anesthesia-related complications.

The authors concluded with remarks that implantation of an IOL at the time of cataract extraction under combined systemic ketamine and peribulbar lidocaine anesthesia appeared to be well tolerated and produced significant visual improvement in pediatric patients in Nepal. Primary posterior capsulotomy and AV helped prevent visual axis opacification without a significant increase in complications.

Effect of a modified optic edge design on visual function Textured-edge versus round-anterior, slope-side edge

Hayashi K, Hayashi H,
J Cataract Refract Surg 2004; 30:1668-74

Many studies report that approximately 20% to 65% of patients who have implantation of an intraocular lens (IOL) notice various photic symptoms including glare, halos, and streaks of light. Some patients are so bothered by the unwanted images caused by glare that they request explantation of the IOL. Moreover, it has been shown that visual function in pseudophakic patients is disturbed to an extent in the presence of a glare source, particularly under mesopic conditions.

Many glare symptoms are thought to be related to internal light reflections from the anterior surface and lateral edge of the IOL. The truncated edge on the side of the minor axis of an ovoid IOL or the positioning holes can cause significant glare symptoms. More recent studies report that some patients who receive a square edged acrylic IOL (MA60BM or MA30BA, Alcon Surgical) also have bothersome glare symptoms. In an experimental study, Holladay and coauthors showed that a sharp optic edge forms a more intense peak of reflected light on the retina than a round edge and can lead to photic phenomena. Based on these studies, manufactures are improving optic edge design in an effort to eliminate glare symptoms.

The purpose of this study was to compare the impairment in visual function caused by glare with 2 acrylic intraocular lenses (lOLs) with different modified optic edges. Fifty-four patients had implantation of an IOL with a textured edge (Alcon MA60AC) in 1 eye and an IOL with a round-anterior, sloped-sided edge (AMO AR40e) in the opposite eye. Visual acuity was measured at 5 contrast visual targets (100%, 25%, 10%, 5%, and 2.5%) (contrast visual acuity) under photopic and mesopic conditions with and without a glare source approximately 1 month after surgery using the Contrast Sensitivity Accurate Tester (Menicon CAT-2000).

The mean mesopic contrast visual acuity at moderate to low-contrast visual targets was significantly worse in the presence of a glare source in both groups, whereas photopic contrast visual acuity did not change significantly. There were no significant differences between the 2 groups in the mean visual acuity or in photopic or mesopic lighting contrast visual acuity with and without a glare source. Furthermore, there was no significant difference in loss of contrast visual acuity in the presence of glare. The authors concluded that mesopic contrast sensitivity with both acrylic lOLs was impaired significantly in the presence of glare, but the impairment of contrast sensitivity from glare was approximately the same between eyes with a textured-edge IOL and eyes with a round-anterior, sloped-sided edge IOL.

Higher-order aberrations of lenticular opacities

Sachdev N, Ormonde SE, Sherwin T, McGhee CNJ
J Cataract Refract Surg 2004; 30:1642-8

Cataract is the leading cause of preventable blindness worldwide,' and cataract surgery is the most common surgical procedure in those older than 65 years.

In current clinical practice, assessment of monocular visual acuity is usually the primary test of visual function in determining the need for cataract surgery and for evaluating its success. This is generally assessed using a Snellen chart composed of high contrast letters placed 6 m (20 feet) from the patient in a glare free environment. However, this is not representative of normal everyday situations experienced by the elderly; thus, it is not surprising that patients' perception of their visual function in the presence of cataract does not correlate well with their measured level of visual acuity. This suggests that the best assessment and prioritization of patients for cataract surgery require information in addition to high contrast visual acuity.

The purpose of this study was to measure and quantify higher-order aberrations induced by different types of lenticular opacities. Patients with lenticular opacities were recruited from outpatient clinics of a major tertiary referral center for ophthalmology. Patients were included if they had clinically evident, mild to moderate lenticular opacity with no coexisting ocular pathology. Patients were examined using standard preoperative techniques with additional assessment by wavefront aberrometry (Zywave®, Bausch & Lomb) and Scheimpflug photography (EAS-1000, Nidek). For comparison, 20 eyes of 10 subjects with no lenticular opacity (control group) were recruited and assessed in an identical manner.

Thirty persons were recruited and 40 eyes assessed, 20 with lenticular opacities. Ten eyes had predominantly cortical opacification, and 10 had mainly nuclear opacification. In eyes with predominantly cortical opacification, the mean logMAR uncorrected visual acuity (UCVA) was 0.5 ± 0.2 (SD) (6/18 Snellen equivalent) and the mean logMAR best spectacle-corrected visual acuity (BSCVA), 0.2±0.2 (6/9). Analysis of aberrometry data for a 6.0 mm pupil in this group revealed an increase in coma of cosine phase (Z31, P = .06) and tetrafoil of cosine phase (Z44, P = .07) compared to eyes in the control group. Eyes with predominantly nuclear opacification had a mean logMAR UCVA of 0.7 ± 0.2 (6/30) and a logMAR BSCVA of 0.4 ± 0.2 (6/15). Aberrometry data for this cohort for a 6.0 mm pupil showed a statistically greater amount of spherical aberration (Z4°, P = .001) and tetrafoil of cosine phase (Z4 4, P = .005; Z4- 4, P = .004)

This pilot study suggests that different types of early lenticular opacities induce different wavefront aberration profiles. Predominantly cortical opacification produced an increase in coma and nuclear opacification induced an increase in spherical aberration compared to eyes without opacities. Both types of lenticular opacities also induced a higher amount of tetrafoil. This could explain the significant visual symptoms in patients with early cataract and relatively good high contrast Snellen acuity.

Cost effectiveness of photodynamic therapy with verteporfin for age related macular degeneration: the UK case

Smith DH, Fenn P, Drummond M
Br J Ophthalmol 2004;88:1107-12

Age related macular degeneration (AMD) is the leading cause of registered blindness in the United Kingdom, has prevalence of >7% in the elderly, and is the main cause of severe and irreversible loss of vision in developed countries, leading to quality of life decrements. The wet form of AMD is characterised by choroidal neovascularisation (CNV) and may lead to acute visual loss. Until recently, the only available treatment for wet AMD was laser photocoagulation, but in the case of those with subfoveal lesions (about 50%), it leads to immediate loss of vision.

The purpose of this study was to estimate the potential cost effectiveness of photodynamic therapy (PDT) with verteporfin in the UK setting. Using data from a variety of sources a Markov model was built to produce estimates of the cost effectiveness (incremental cost per quality adjusted life year (QALY) and incremental cost per vision year gained) of PDT for two cohorts of patients (one with starting visual acuity (VA) of 20/40 and one at 20/100) with predominantly classic choroidal neovascular disease over a 2 year and 5 year time horizon. A government perspective and a treatment cost only perspective were considered. Probabilistic and one way sensitivity analyses were undertaken.

From the government perspective, over the 2 year period, the expected incremental cost effectiveness ratios range from £286 000 (starting VA 20/100) to £76 000 (starting VA 20/40) per QALY gained and from £14000 (20/100) to £34000 (20/40) per vision year gained. A 5 year perspective yields incremental ratios less than £5000 for vision years gained and from £9000 (20/40) to £30000 (20/100) for QALYs gained. Without societal or NHS cost offsets included, the 2 year incremental cost per vision year gained ranges from £20 000 (20/100) to £40 000 (20/40), and the 2 year incremental cost per QALY gained ranges from £412 000 (20/100) to £90 000 (20/40). The 5 year time frame shows expected costs of £7000 (20/40) to £10 000 (20/100) per vision year gained and from £38 000 (20/40) to £69 000 (20/100) per QALY gained.

This evaluation suggests that early treatment (that is, treating eyes at less severe stages of disease) with PDT leads to increased efficiency. When considering only the cost of therapy, treating people at lower levels of visual acuity would probably not be considered cost effective. However, a broad perspective that incorporates other NHS treatment costs and social care costs suggests that over a long period of time, PDT may yield reasonable value for money.

Consequences of amblyopia on education, occupation, and long term vision

Chua B, Mitchell P
Br J Ophthalmol 2004;88:1119-21

Amblyopia is a disorder of reduced visual function from abnormal visual experience caused by strabismus, anisometropia, or visual form deprivation during the critical period of visual development. Amblyopia is the most common cause of monocular visual impairment in children and young adults. Debate and research into amblyopia intensified following Snowdon and Stewart Brown's report, which identified a lack of scientific evidence for the natural history, associated disabilities, and the treatment efficacy of amblyopia. The best described long term consequence of amblyopia is an increased risk of bilateral blindness, caused most frequently by traumatic eye injury in younger people and age related macular degeneration in older people. Recent UK data indicate an increased lifetime risk of vision loss in individuals with amblyopia and improved visual acuity in the amblyopic eye following vision loss in the non-amblyopic eye.
The purpose of this study was to describe the effect of amblyopia on education, occupation, and 75 year incident vision loss.
3654 participants aged 49 years or older participated in the Blue Mountains Eye Study (BMES I, 1992-4) and 2335 (75.1% of survivors) were re-examined (BMES II, 1997-9). All participants underwent detailed eye examination. Amblyopia, defined as best corrected visual acuity of less than or equal to 6/9 and not attributable directly to any underlying structural abnormality of the eye or the visual pathway, was identified in 118 participants (3.2%) in BMES I, of whom 73 were re-examined in BMES II.
The mean age of people with amblyopia seen at baseline was 67.0 years. Amblyopia did not affect lifetime occupational class (p = 0.5), but fewer people completed higher university degrees (p = 0.05). In people with amblyopia, there was an increased risk of 5 year incident visual impairment in the better seeing eye worse than 6/12, relative risk (RR) 2.7, 95% confidence interval (Cl) 1.6 to 4.6. One of 11 (9.1%) people with amblyopia showed significant improvement in visual acuity in the poorer seeing eye after a two line (10 logMAR letter) vision loss in the better seeing eye.
The authors concluded with remarks that further longitudinal data are warranted to provide a more complete account of the natural history of amblyopia and the plasticity of the visual system.
In authors opnion a 2 week course of oral prednisolone, tapered postoperatively, produced a better recovery of the BAB than a single dose of intravenous methylprednisolone and is thus the recommended preoperative regim.

Changes in ocular aberrations after instillation of artificial tears in dry-eye patients

Mico’ RM, Ca’liz A, Alio’ JL
J Cataract Refract Surg 2004; 30:1649-52
The tear film is a factor contributing to instability in ocular aberrations that has received increasing attention. Several clinical studies support the hypothesis that increased aberrations consequent to tear-film disruption may reduce retinal image quality. Since the front surface of the precorneal tear film is the most anterior optical surface of the eye and the most powerful since it is associated with the greatest change in the refractive index, any local change in tear-film thickness and regularity will introduce additional aberrations into the eye's optical system. Maintenance of a smooth, intact tear film is therefore essential for achieving high-quality retinal images.

Since the absence of a tear film (ie, dry-eye syndrome) contributes to decreased visual function, it would be expected that after artificial tear instillation, the decrease in visual function caused by the lack of the tear film would disappear. To quantify the optical effect of artificial tear instillation in subjects who lack a tear film, we measured the optical aberrations in dry-eye subjects before and after artificial tear instillation.
The purpose of this study was to study the effect of artificial tear instillation on ocular aberrations in dry-eye patients.

Ocular aberrations (total, spherical-like, and coma-like) were measured with a Hartmann-Shack aberrometer before and after artificial tear instillation (immediately and 10 minutes later) in 15 eyes of 15 dry-eye patients.
Optical aberrations showed a statistically significant reduction after artificial tear instillation (P<.01). Total aberrations decreased on average by a factor of 2 to 3 times immediately after instillation; the reduction was maintained after 10 minutes (P>.01). The authors concluded that after artificial tear instillation, the reduction in optical aberrations associated with an increasingly irregular tear film may cause an improvement in the optical quality of dry eyes. Wavefront analysis facilitates the evaluation of improvement in optical quality after artificial tear instillation in patients with dry eye.

Functional Outcome After Trypan Blue-assisted Vitrectomy for Macular Pucker: A Prospective, Randomized, Comparative Trial

Haritoglou C, Eibl K, Schaumberger M, Mueller AJ, Priglinger S, Alge C and Kampik A
Am J Ophthalmol 2004:138:1-5

Epiretinal membranes (ERMS) were initially described by lwanoffin 1865. Histologic evaluations of tissue removed during vitrectomy showing the internal limiting membrane (ILM) to he a common feature enhanced our understanding of the underlying pathology and helped to develop the surgical technique as applied today. Despite of possible adverse effects of ILM peeling during macular pucker surgery, the surgical removal of ERMs and the ILM has become a standard procedure in ophthalmology. A previous prospective study evaluating the effect of ILM peeling in macular hole surgery showed no ERM formation after a follow-up of 32 months.

Recently, the application of dyes such as indocyanine green (ICG) and trypan blue during macular surgery has become popular to assist the removal of ERMs, the ILM, or both. Whereas the use of ICG to assist ILM peeling is controversial, with some investigators describing possible adverse effects on functional outcome and others observing no dye-related complications, no such problems have been reported along with the application of trypan blue in clinical practice. Initially used to assist capsulorhcxis, the dye was also suggested for intraoperative application to better visualize epiretinal tissue and facilitate its removal. In vitro studies have disclosed no dye-related roxic effects on human retinal pigment epithelium in concentrations up to 0.30%. This prospective, randomized, comparative study was performed to describe results after trypan blue-assisted pars plana vitrectomy for idiopathic macular pucker.

The purpose of this prospective, randomized, comparative study was to evaluate funtional oucome after the intraoperative application of 0.06% trypan blue during vitrectomy for macular pucker. Forty-three eyes of 43 consecutive patients, 30 women and 13 men, were incorporated in the study. Patients were ran domized into two groups: group 1 (n = 22) with trypan blue (0.06%) staining, and group 2 (n = 21) without trypan blue staining. Functional outcome (best-corrected visual acuity, Goldmann perimetry) was evaluated 1 day before surgery, at 6 weeks, and at intervals of 3, 6, and 12 or more months postoperatively. Only patients with an idiopathic macular pucker were included. In all patients, a standard three-port pars plana vitrectomy with peeling of an epiretinal membrane (ERM) and the internal limiting membrane was performed. No other modification of the surgical procedure, except the use of trypan blue was made between the two group.

Mean age was 68.9 years in group 1 (with trypan blue) and 69.4 in group 2 (without trypan blue). Median best-corrected visual acuity was 20/63 in both groups (range, 20/200-20/40; P > .5) before surgery. Mean follow-up time was 5.8 months in group 1 and 5.3 months in group 2. After surgery, median visual acuity had increased to 20/40 in both groups (range, 20/500 to 20/20 in group 1 and 20/100 to 20/20 in group 2; P < .001 for both groups). The difference between both groups was not statistically significant (P > .5). An improvement of visual acuity (gain of 2 or more lines) was seen in 16 patients of both groups. No postoperative visual field defects were noted.

The authors concluded that trypan blue-assisted vitrectomy for macular pucker leads to good functional results with no dye-related adverse effects after short follow-up. Trypan blue might be especially applicable in cases in which the borders of the ERM are difficult to define. Hypothetical advantages, such as fewer recurrences of ERMs after trypan blue staining, will have to be evaluated during further follow-up of patients.

Treatment of conjunctival carcinoma squamous cell with photodynamic therapy

Barbazetto IA, Lee TC And Abramson DH
Am J Ophthalmol 2004; 138: 183-9.

The tratment of squamous cell carcinoma (SCC) of the conjunctiva is complicated by high recurrence rates, damage to adjacent ocular structures, or both, in cases where more invasive interventions are required. Currently available therapeutic options include surgical excision, cryotherapy, and radiation, as well as investigational approaches with topical chemotherapy, interferon, and antiviral drugs. However, larger lesions and those involving the cornea remain a therapeutic challenge, despite the increasing variety of treatments.
Photodynamic therapy (PIT) could potentially represent a new approach based on reports in the recent literature by other subspecialties. Photodynamic therapy is a minimally invasive treatment involving activation of a photosensitizing drug by visible light to produce activated oxygen species that promote tumor destruction. The potential benefit of treating superficial malignancies with PDT is the preservation of adjacent anatomic structures, providing efficient tumor control with desirable cosmetic results. In dermatology, otolaryngology, and gastroenterology, PDT has been investigated for its effectiveness in treating minimally invasive early SCC of the head and neck and the esophagus. The presented results in vitro and in vivo seem to be encouraging enough to evaluate this technique as an additional therapeutic option for SCC of the conjunctiva.

The aim of this study was to describe the clinical and angiographic response of squamous cell carcinoma (SCC) of the conjunctiva to treatment with photodynamic therapy (PDT).

In this prospective study, three patients (62 to 86 years old) with SCC of the conjunctiva were treated with PDT. Patients received one to three treatments of verteporfin (6 mg/m2 body surface area, intravenously). The light dose was calculated as 50 J/cm2. All tumors were irradiated 1 minute after injection. The mean follow-up time was 8.6 months (7 to 12 months). Main outcome measurements were clinical and angiographic response and treatment related side effects.

One week after treatment, angiographic occlusion of tumor vasculature and normal conjunctival vessels was observed in all patients. Tumor regression was noted in all patients 1 month after treatment. Two patients had complete regression (clinical and angiographic observation) after one or two treatments for the entire follow-up time. One tumor involved large aspects of the conjunctiva and cornea. In this case, only the treated areas showed tumor regression. PDT caused minimal temporary local irritation in two patients, and small conjunctiva hemorrhages and mild transient chemosis in the three eyes directly after treatment. One patient had infusion related back pain.
The preliminary results of this study suggest that PDT may be a valuable addition to the treatment of patients with SCC of the conjunctiva. However, longer follow-up is necessary to assess the duration and degree of tumor control.