Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations

BACKGROUND/OBJECTIVES

To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt.

SUBJECTS/METHODS

A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed.

RESULTS

IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75).

CONCLUSIONS

Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.

Efficacy of toric intraocular lens implantation with high corneal astigmatism within the United Kingdom's National Health Service

OBJECTIVES

To determine the efficacy of toric intraocular lens (TIOL) implantation in cataract surgery patients with high levels of pre-operative corneal astigmatism and ocular co-morbidities in a state funded, National Health Service (NHS) hospital.

METHODS

Retrospective cohort study involving consecutive cases of TIOL implantation in cataract surgery with over 3.00DC of pre-operative corneal astigmatism. Subjects were implanted with the Tecnis TIOL (Abbot Medical Optics) with capsular tension ring stabilisation using the Callisto system (Carl Zeiss Meditec). Visual acuity and refraction were assessed at 4-6 weeks post-operatively. Vector analysis was used to calculate the intended refractive correction, surgically induced refractive correction (SIRC), correction ratio (CR), error of magnitude (EM) and error vector (EV).

RESULTS

Sixty-six eyes of forty-seven subjects aged 73.8 ± 11.9 were included. Eyes with ocular co-morbidities included dry age-related macular degeneration (n = 13), amblyopia (n = 7), high myopia (n = 7), glaucoma (n = 6), previous corneal transplantation (n = 2), nanophthalmos (n = 2) and corneal scarring (n = 1). Pre-operative corneal astigmatism was 4.25 ± 1.69DC (range 3.00-12.00), post-operative refractive astigmatism was 1.31 ± 1.05DC (range 0.00-6.50DC) and post-operative unaided visual acuity was 0.25 ± 0.19 LogMAR. Vector analysis demonstrated an SIRC of 4.08 ± 1.39DC, CR = 1.1 ± 0.3, EM -0.4 ± 1.0 and EV of 1.23 ± 0.72.

CONCLUSIONS

The results demonstrate the efficacy of TIOL implantation in patients with high corneal astigmatism and provide strong evidence advocating their use in cataract surgery within a state funded hospital eye service. Refractive astigmatism was significantly lower than the pre-operative corneal astigmatism and a low error vector was achieved relative to the magnitude of correction.

Missed case of Axenfeld-Rieger syndrome: a case report

Background

Anterior segment dysgenesis is a failure of normal development of the anterior segment of the eye. The structural anomalies are associated with glaucoma and corneal opacity which may lead to blindness.

Case presentation

A Caucasian male was noted to have 'funny pupils' at the age of seven years but not followed up. He was diagnosed to have Axenfeld-Rieger syndrome at the age of thirty four years when he presented with glaucoma and visual field loss.

Conclusion

Axenfeld-Rieger syndrome is uncommon. There is risk of sight loss due to glaucoma and corneal opacity. Importance of long-term follow up in cases of abnormal ocular findings in early life is emphasised.

Effect of midazolam on anxiety level and pain perception in cataract surgery with topical anesthesia

PURPOSE

To study the effect of sedation on patients' anxiety level and perception of pain during cataract surgery under topical anesthesia.

SETTING

Royal Eye Infirmary, Plymouth, England.

METHODS

This prospective controlled double-blind clinical trial comprised 100 consecutive patients having routine phacoemulsification with posterior chamber intraocular lens implantation under topical anesthesia by a single experienced surgeon. Patients were randomized to receive intravenous midazolam (0.015 mg/kg body weight) 15 minutes before surgery or no sedation. The main evaluation criteria were the anxiety based on the 6-item, short form of the State-Trait Anxiety Inventory, the pain score using a visual analog scale, and overall patient satisfaction.

RESULTS

All operations were uneventful, and no side effects were noted from the use of midazolam. Anxiety scores were significantly higher on arrival at the hospital than just before the commencement and after the conclusion of the surgery in both groups (P<.05). Patients were less anxious after administration of midazolam, but this did not achieve statistical significance. The mean pain score was 0.29 (range 0 to 4) in the sedation group and 0.38 (range 0 to 4) in the control group; the difference between groups was not statistically significant. The patients were equally satisfied in both groups, with mean scores of 3.84 (range 0 to 4) and 3.88 (range 2 to 4), respectively.

CONCLUSIONS

Patients who had cataract surgery under topical anesthesia were highly satisfied with their operative experience and reported minimal pain during surgery. Anxiety levels diminished after arrival at the hospital, possibly because of reassurance by experienced staff. Intravenous midazolam did not seem to significantly reduce pain or anxiety.

Efficacy and safety of sedation with propofol in peribulbar anaesthesia

PURPOSE

To evaluate the efficacy and safety of a sub-anaesthetic dose of propofol for reducing patient recall of peribulbar block in eye surgery.

METHODS

A retrospective analysis of patients scheduled for elective cataract extraction or trabeculectomy using peribulbar anaesthesia with an intravenous bolus of propofol to provide sedation during the administration of the block. The dose of propofol was based on age and body weight. Patients' vital signs were monitored with continuous pulse oximetry and blood pressure measurements. Efficacy of sedation was assessed by recording patient's recall of the anaesthetic block after 8-10 min.

RESULTS

Data from 2043 patients were analysed. The dose of propofol used ranged from 15-75 mg. Propofol was effective in abolishing recall in 87.5% of the patients studied. Only four patients required airway support but no major systemic side effects were encountered.

CONCLUSIONS

A single sub-anaesthetic dose of propofol prior to administering peribulbar block is effective in reducing recall of the injection and safe without major systemic side effects.

Late surface opacification of Hydroview intraocular lenses

PURPOSE

To describe clinical and pathological features of Hydroview intraocular lenses undergoing delayed surface opacification resulting in visual deterioration.

METHODS

Twenty one eyes which underwent uncomplicated phacoemulsification and Hydroview lens implantation with good visual recovery, presenting at 46-146 weeks post-surgery with visual deterioration and glare symptoms resulting from opacification of the implants, were included in the study. Twelve eyes had severe opacification, of which nine underwent intraocular lens exchange and three more are still awaiting surgery. The method of explantation is described. The explanted intraocular lenses were examined using light microscopy, scanning electron microscopy and x-ray microanalysis using a light element detector.

RESULTS

Light microscopy and scanning electron microscopy revealed diffuse granular deposits of approximately 5 microm diameter covering the optic surfaces but sparing the lens haptics. Light microscopic staining techniques and x-ray microanalysis confirm the major component of the deposits to be calcium phosphate salts.

CONCLUSIONS

Late opacification of Hydroview intraocular lens implants is uncommon and aetiology seems to be multifactorial. Implant exchange is necessary to restore sight in some cases. As new materials are increasingly used it is important to highlight such unusual occurrences.

Clinical and pathologic findings in human keratolimbal allograft rejection

OBJECTIVE

To characterize the clinical and pathologic features of cadaveric keratolimbal allograft (KLAL) rejection.

DESIGN

The study design is descriptive.

PARTICIPANTS

Four patients (five eyes) with KLAL rejection are reported.

INTERVENTION

All patients were subjected to slit-lamp biomicroscopy, treatment of rejection, and ultimately required repeat KLAL surgery. In three patients (four eyes), specimens obtained at the time of repeat surgery were subjected to immunohistochemical staining against the following immune and surface human antigens: CD4, CD8, CD19, CD3, DR, CK19, CK3, and vimentin.

RESULTS

Signs of allograft rejection included intense sectoral injection, diffuse or perilimbal conjunctival injection, edema, and infiltration of the KLAL grafts, leading to punctate epithelial erosions, epithelial defects, and surface keratinization. Rejected specimens revealed T-lymphocyte infiltration (CD4:CD8, 2:1) with strong HLA-DR (MHC class II) expression. The epithelium stain results were positive for cytokeratin 19 and weakly positive to absent for cytokeratin 3. The epithelial stain results were weakly positive for vimentin in only one specimen.

CONCLUSIONS

KLAL rejection is a newly recognized entity. Pathologic findings of rejected specimens indicate that this is a T-cell mediated rejection phenomenon. The pattern of cytokeratin staining provided little evidence that the epithelium covering KLALs had a corneal phenotype. The scarcity of vimentin-positive epithelial cells suggests that the stem-cell/transient-cell pool was probably depleted. Early recognition of clinical rejection is important, as treatment with immunosuppressive therapy may reverse the process.

Long-term results and complications after trabeculectomy with a single per-operative application of 5-fluorouracil

We retrospectively evaluated a consecutive series of 45 patients (45 eyes) who underwent trabeculectomy augmented with a single intra-operative 5 minute application of 5-fluorouracil (5-FU; 25 mg/ml). All patients were at an increased risk of subconjunctival fibrosis and surgical failure. The mean follow-up period was 24 months (range 12-42, SD 6.9). The mean pre-operative intraocular pressure (IOP) was 29.1 mmHg (SD 6.1) and the mean IOP at the last post-operative visit was 16.6 mmHg (SD 6.4) (p < 0.0001) with a mean IOP reduction of 42%. The number of medications reduced from a mean of 2.3 (SD 0.7) pre-operatively, to 0.8 (SD 0.7) post-operatively (p < 0.0001) and 22 eyes (49%) required no topical treatment for IOP control. An IOP of 21 mmHg or less with or without medications was achieved in 80% of cases. There was no significant difference in final IOP or success rate over time between low- and high-risk patients, although the low-risk patients did better in the first 12-18 months. Complications included hypotony maculopathy in 2 cases (4%), leaking bleb in 5 cases (11%) and giant bleb in 1 case (2%), giving a total of 8 cases (18%) with bleb-related sequelae. In the short to medium term, a single per-operative application of 5-FU is a useful adjunctive treatment during glaucoma filtering surgery for low- to moderate-risk cases, although a steady increase in the failure rate was associated with increasing length of follow-up.

Photorefractive keratectomy for hyperopia: six months results in 45 eyes

OBJECTIVE

To evaluate the safety and efficacy of photorefractive and photoastigmatic keratectomy for hyperopia.

METHODS

The Chiron Keracor 116 excimer laser (Chiron Technolas, Munich, Germany) was used to create a peripheral annular ablation profile for the correction of hyperopia and a prior cylindrical ablation in the negative axis for correction of the astigmatic component in 45 consecutive eyes with up to +6.50 diopters (D). All patients were followed for a minimum of 6 months.

RESULTS

At 6 months, mean subjective refraction was +0.12 D (standard deviation, 0.70), with 87% within 1 D of emmetropia. Ninety-three percent achieved uncorrected visual acuity of 20/40 or better. Three eyes (6.7%) lost 2 lines of best spectacle-corrected visual acuity and six eyes (13.3%) gained 2 lines or more.

CONCLUSIONS

Photorefractive and photoastigmatic keratectomy effectively and predictably reduced hyperopia, improving uncorrected visual acuity in all patients at 6 months. Longer follow-up is required to be certain that refractive changes are stable.

Blow-out fracture of the orbit associated with inflation of an airbag: a case report

We report a case of blow-out fracture of the orbit in a 37-year-old woman which was caused by deployment of an airbag following collision with a stationary vehicle whilst travelling at 30 m.p.h. The fracture did not become evident until she blew her nose some hours later. She was treated with antibiotics orally and made a full and complete recovery. Therefore, refinements in the design of airbags are warranted.

Cracked cartridges during foldable intraocular lens implantation

We describe five routine phacoemulsification procedures in which a longitudinal split in the injector cartridge occurred during foldable intraocular lens (IOL) implantation. In some cases, this was associated with a broken lens. All lenses (STAAR AA-4203VF) were folded, and implantation was attempted through a 3.5 mm corneal or scleral incision. Visual outcome was not adversely affected in any case. The systems for introducing foldable IOLs have not been perfected, and further refinements in materials and techniques are required.

Subconjunctival bupivacaine versus topical amethocaine in strabismus surgery

A prospective study was performed to evaluate and compare the effect of subconjunctival bupivacaine and topical amethocaine on pain relief after strabismus surgery. A total of 40 children scheduled for elective operation were randomly allocated to receive either subconjunctival bupivacaine or topical amethocaine at the end of surgery. Post-operative pain was evaluated using a four-point assessment score. We show that both techniques provide good post-operative pain relief. We advocate that either could be used routinely in strabismus surgery although topical amethocaine is easier to administer.

Subconjunctival bupivacaine in strabismus surgery

A prospective study was performed to assess the effect of subconjunctival bupivacaine on pain relief following strabismus surgery. A total of 36 children were randomly allocated to receive either subconjunctival infiltration of bupivacaine or normal saline at the conclusion of surgery. Post-operative pain was evaluated using a 4-point assessment score. Subconjunctival bupivacaine provided significantly better post-operative pain relief (P < 0.001). We suggest that it could be used routinely in strabismus surgery, as it improves post-operative comfort thereby facilitating day case surgery.