Madhavan S. Rajan

Ex Vivo Expansion and Transplantation of Limbal Epithelial Stem Cells

OBJECTIVE To determine, using objective measures, the outcome of ex vivo cultured limbal epithelial stem cell (LESC) transplantation performed in compliance with good manufacturing practice using a novel culture system without 3T3 feeder cells. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Ten eyes of 10 patients with profound LESC deficiency arising from chemical injury (4 eyes), aniridia (3 eyes), ectodermal dysplasia (1 eye), Reigers anomaly with Pax6 haploinsufficiency (1 eye), and unknown cause (1 eye). METHODS Allogeneic (7 eyes) or autologous (3 eyes) corneal LESCs were cultured on human amniotic membrane. Tissue was transplanted to the recipient eye after superficial keratectomy. Impression cytology and confocal microscopy were performed 6 months after surgery with clinical follow-up to 13 months. Success was defined as an improvement in the defined clinical parameters of LESC deficiency, an improvement in visual acuity, the restoration of a more normal corneal phenotype on impression cytology, and the appearance of a regular hexagonal basal layer of cells on corneal confocal microscopy. MAIN OUTCOME MEASURES Clinical parameters of LESC deficiency (loss of epithelial transparency, superficial corneal vascularization, epithelial irregularity, and epithelial breakdown), visual acuity, impression cytology and cytokeratin expression profiles, and in vivo confocal corneal confocal microscopy. RESULTS The success rate using this technique was 60% (autografts 33%, allografts 71%). All patients with a successful outcome experienced an improvement in visual acuity of >/=2 lines Snellen acuity. Preoperatively, CK3+ and CK19+ cells accounted for 12+/-2.4% (mean +/- standard error of the mean) and 80+/-2.15% of cells, respectively, whereas postoperatively these accounted for 69+/-6.43% (P<0.0001) and 30+/-6.34% (P<0.0001) of cells, respectively. Goblet cells accounted for 8+/-1.19% of cells preoperatively and 1+/-0.35% of cells postoperatively (P<0.0001). CONCLUSIONS These data demonstrate that it is possible to culture LESCs ex vivo in compliance with good manufacturing practice regulations. A set of objective outcome measures that confirm the efficiency of this technique in treating LESC deficiency is described. The widespread use of such standardized and objective outcome measures would facilitate a comparison between the different culture methods in use.

Partial coherence laser interferometry vs conventional ultrasound biometry in intraocular lens power calculations.

Aims The purpose of the study was to compare optical biometry based on partial coherence laser interferometry (PCLI) principle to conventional ultrasound biometry in the accuracy of intraocular lens (IOL) power calculations. The role of partial coherence laser interferometry in pseudophakic axial length measurement was analysed in the study.Methods In a prospective randomised clinical trial, 100 patients undergoing phacoemulsification cataract surgery were randomised to undergo biometry by either partial coherence laser interferometry (IOL Master) or the applanation ultrasound technique. The IOL material, design and the IOL formula were standardized. The mean error and mean absolute error were calculated and compared using paired t-tests.Results One hundred patients were included in this prospective randomised trial, of whom 50 patients underwent optical biometry and 50 patients had biometry by applanation ultrasound. The mean age of patients in the PCLI group was 67 ± 6 yrs as compared to 71 ± 8 yrs in the ultrasound group (P > 0.05). The preoperative mean axial length was 23.47 ± 1.1 mm in the PCLI group (range 20–27.6 mm) and 23.43 ± 1.2 mm in the ultrasound group with a range of 20.1–27 mm (P > 0.05). The mean absolute error (MAE) in the PCLI group was 0.52 ± 0.32 D (upper and lower 95% CI 0.62 and 0.42 respectively). The MAE in the ultrasound group was 0.62 ± 0.4 D (upper and lower CI 0.73 and 0.50 D respectively). Eighty-seven per cent of patients were within ± 1 D in the PCLI group as compared to 80% in the ultrasound group (P = 0.24). The MAE of axial length difference with optical biometry was 0.13 mm ± 0.13 SD (range −0.42 to 0.78 mm) in the PCLI group and 0.19 ± 0.13 mm in the ultrasound group. There was a mean shortening of the eye length in the PCLI group postoperatively. Optical biometry improved the post op refraction by 16% on retrospective IOL power calculations. Eight per cent failed biometry with IOL Master (dense cataracts (4%) and fixation instability due to macular degeneration (4%)).Conclusion The non contact optical biometry using the partial coherence laser interferometry principle improves the predictive value for postoperative refraction and is a reliable tool in the measurement of intraocular distances in pseudophakic eyes.

Clinical assessment of the Zeiss IOLMaster

Purpose: To compare axial lengths and intraocular lens (IOL) power calculations obtained with the Zeiss IOLMaster® by 2 observers with different training grades and to assess the agreement between optical and acoustic biometry. Setting: Department of Ophthalmology, Pembury Hospital, The Laser Eye Clinic, Kent, United Kingdom. Methods: In this prospective study, optical biometry was performed twice in 79 patients: first by a qualified ophthalmic nurse and second by 1 of several health care assistants without formal nursing training. In the same group of patients, the qualified nurse also obtained ultrasonic measurements to compare the 2 clinical methods. Results: There was a high correlation coefficient for axial length and IOL power measurements (0.99 each) between the experienced examiner and the inexperienced examiners. The coefficient of repeatability (2 SD) was 0.58 diopter (D) for IOL power (mean 0.04 D) and 0.07 mm for the axial length (mean 0.00 mm). The correlation coefficient of IOLMaster measurements with A‐scan measurements done by the same experienced ophthalmic nurse was 0.97 for IOL power and 0.98 for axial length. The limits of agreement (mean ± 2 SD) were between +0.50 and −2.40 D for IOL power calculations and between +0.7 mm and −0.2 mm for axial length measurements. Conclusions: Optical biometry showed excellent repeatability using different examiners regardless of their medical training. The agreement with ultrasonic measurements and the precision of the method need further evaluation.

Reply to "Descemet stripping automated endothelial keratoplasty: effect of intraoperative lenticule thickness on visual outcome and endothelial cell density".

Purpose: To determine the correlation between the intraoperative donor lenticule thickness in Descemet stripping automated endothelial keratoplasty (DSAEK) and both the best-corrected visual acuity (BCVA) and endothelial cell density (ECD) at 6 months. To describe relevant surgical considerations with regard to the choice of microkeratome head. Design: Prospective case series. Methods: Thirty-five patients (37 eyes) undergoing DSAEK were included in this prospective case series. Intraoperative donor lenticule thickness, assessed by ultrasound pachymetry, was compared with BCVA and ECD 6 months postoperatively. Results: Mean BCVA logarithm of the minimal angle of resolution (logMAR) was 0.58 preoperatively and 0.29 6 months postoperatively. Three eyes were excluded from BCVA analysis. The average donor lamellae thickness was 175 μm. Mean ECD loss was 39% 6 months postoperatively compared with that preoperatively. There was no correlation between donor lamella pachymetry and BCVA logMAR and ECD at 6 months in this series (P = 0.13 and P = 0.09, respectively). Analogous to our findings, a review of published reports on donor pachymetry in DSAEK did not provide data to suggest a correlation between donor corneal thickness and postoperative BCVA or ECD. Conclusions: Donor lenticule thickness does not have a direct effect on 6-month postoperative visual acuity or endothelial cells. Efforts should be made to reduce surgical trauma to the lenticule rather than adhering to a strict depth when cutting the graft. We propose using the Moria 350 μm microkeratome head for corneal thickness more than 600 μm and the 300 footplate for corneal thickness less than 600 μm.

Preconditioned donor corneal thickness for microthin endothelial keratoplasty.

Purpose: To describe a novel surgical technique to produce thin endothelial grafts for Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: Thirteen human cadaveric corneas in organ culture were randomized into conventional (n = 7) and microthin (n = 6) DSAEK groups. Grafts in the conventional DSAEK group were prepared using the conventional DSAEK technique of a single microkeratome pass with a 350-&mgr;m cutting head. Corneas in the microthin group were preconditioned to achieve a target central thickness of 530 &mgr;m before graft dissection with a 350-&mgr;m microkeratome head. Preconditioning involved stromal dehydration under pachymetric control using sterile airflow for 15-second increments. Donor and graft thicknesses were assessed with optical coherence tomography, and endothelial viability with trypan blue and alizarin red staining. Results: Mean endothelial graft thickness obtained using the microthin DSAEK technique was 106 &mgr;m (SD, 32 &mgr;m) compared with 177 &mgr;m (SD, 33 &mgr;m) obtained using conventional DSAEK technique (P = 0.0024). Donor preconditioning yielded a predicted reduction of 100 &mgr;m in graft stromal thickness at a rate of 1.5 &mgr;m/s and mean duration of 72 seconds. The average anterior lamella thickness (cut depth) obtained in microthin and conventional DSAEK groups were 424 and 431 &mgr;m, respectively (P = 0.84). There was no difference in endothelial viability between the 2 groups. There were no corneal perforations during graft preparation in this study. Conclusions: Donor preconditioning by pachymetry-controlled stromal dehydration achieved significantly thinner endothelial grafts compared with the conventional DSAEK technique without compromise to endothelial viability or graft wastage.

Wavefront-Guided Retreatment After Primary Wavefront-Guided Laser In Situ Keratomileusis in Myopes and Hyperopes: Long-term Follow-up

PURPOSE To assess the long-term safety, predictability, and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) retreatment in myopes and hyperopes following primary wavefront-guided LASIK. DESIGN Retrospective nonrandomized case series. METHODS Wavefront-guided retreatment was performed by a single surgeon (D.G.). A cohort of 63 eyes of 41 patients were studied, investigating refractive outcome, uncorrected visual acuity (UCVA), and best-corrected visual acuity before and after wavefront-guided LASIK retreatment. RESULTS The mean spherical equivalent (MSE) prior to primary LASIK in the myopic group (46 eyes) was -5.4 +/- 2.5 diopters (D) (range, -1 to -11.25 D). After the final retreatment the MSE was -0.08 +/- 0.45 D (range, +1.25 to -1.25) with 82.6% achieving +/-0.5 D and 95.6% +/-1 D of emmetropia. The initial MSE in the hyperopic group (17 eyes) was +1.91 +/- 1.13 D (range, +0.25 to +5.73 D). After the final retreatment the MSE was +0.23 +/- 0.43 D (range, -0.5 to +1.25) with 88.2% achieving +/-0.5 D and 100% +/-1 D of emmetropia. Logarithm of the minimal angle of resolution UCVA was 0.22 +/- 0.21 prior to primary LASIK and -0.06 +/- 0.13 after final retreatment for myopes and 0.14 +/- 0.15 prior to primary LASIK and 0.06 +/- 0.16 after final retreatment for hyperopes. The mean follow-up time after LASIK enhancement was 17.75 months in the myopic and 14.6 months in the hyperopic group. CONCLUSION Our results suggest that wavefront-guided retreatment following initial wavefront-guided treatment in myopes and hyperopes has favorable outcome with respect to safety, predictability, and efficacy.

Should active CMV retinitis in non-immunocompromised newborn babies be treated?

Cytomegalovirus (CMV) retinitis in children with congenital CMV infection is known to differ from that described in immunocompromised subjects, because it is present at birth and does not progress postnatally if the child is otherwise immunocompetent. Regarding treatment, there are limited data in infants with symptomatic congenital CMV infection and it is not known whether antiviral drugs alter the prognosis. We describe a case of congenital CMV retinitis that progressed postnatally and our treatment regimen. A 9 day old baby was referred to the eye clinic after having been diagnosed with congenital symptomatic CMV infection. During pregnancy, at 34 weeks, poor growth and ventriculomegaly were noted and a scan at 35 weeks showed bilateral cysts in the occipital horn of the lateral ventricles. He was born at 40 weeks by emergency caesarean section. The mother was a healthy 18 year old woman. His birth weight was 2.1 kg and his head circumference 31.5 cm, both of which were below the 0.4th centile. Brain magnetic resonance imaging confirmed the presence of bilateral occipital cysts and periventricular calcification. Serology and urine tests showed congenital CMV infection. The child had a normal immune system for his age. Eye examination revealed sheathing of the retinal vessels and haemorrhages, which involved the arcades and were more marked in the left eye (Fig 1A, B, C). Exudates were present in both eyes superior to the disc (Fig 1A). The following day the vasculitis in the left eye had progressed and was involving the macula. Treatment with ganciclovir 5 mg/kg/day intravenously was started in view of the active retinitis. One week after …

Listeria monocytogenes sclerokeratitis: a case report and literature review.

Purpose: To report a case of Listeria monocytogenes sclerokeratitis and to review the literature. Methods: Case report. Results: A 25-year-old non-contact lens-wearing male rugby player was referred with progressive infective sclerokeratitis unresponsive to topical antivirals and antibiotics. On examination, visual acuity was perception of light, and a large corneal abscess with overlying epithelial defect and hypopyon was present. The corneal lesion was cheesy white and raised with nasal scleritis. This raised the suspicion of a fungal keratitis. Empirical treatment with intensive topical antifungals was unsuccessful. A previous corneal scrape had been negative for bacteria and fungi. A corneal biopsy was performed, and Listeria monocytogenes was eventually isolated from enrichment culture. Antibiotic sensitivities showed it to be resistant to cefuroxime, methicillin, and ceftazidime but sensitive to all other antibiotics tested including ofloxacin. The treatment course was complicated by a corneal perforation that needed an emergency therapeutic penetrating keratoplasty. Five months later, best-corrected visual acuity was 6/9 + 4, with a clear functioning graft. Conclusions: Listeria monocytogenes is a rare cause of corneal/scleral infection in humans. It often runs an aggressive course and responds poorly to initial intensive antibiotic treatment despite favorable in vitro sensitivities. It can be difficult to culture, and we suggest a corneal biopsy with extended incubation to improve diagnostic yield.

Systemic side effects of topical latanoprost

Latanoprost, a prostaglandin analogue (PGF2), is a commonly used antiglaucoma medication.1 As plasma concentration is low following topical administration, systemic adverse effects are unlikely to occur.1 Studies carried out in asthmatic volunteers with topical prostaglandin PGF2 did not show any respiratory side effects.2 Systemic administration of PGF2 has significant cardiac effects3,4,5 and it has a role in the mediation of sensory (pain) perception.6 Such side effects have not been reported with topical use. We report five cases of chest tightness following the use of latanoprost eye drops.

Interocular axial length difference and age-related cataract

PURPOSE: To evaluate interocular differences in axial length and its relation to increasing axial length and postoperative refractive predictability in patients with age‐related cataract. SETTING: Moorfields Eye Hospital, London, United Kingdom. METHODS: Preoperative biometry and postoperative refractive outcomes were analyzed in a consecutive series of 1537 patients who had uneventful bilateral phacoemulsification. In 1379 patients with bilateral data, the difference in axial lengths between eyes and the magnitude of postoperative anisometropia were compared between 1.0 mm incremental groups of axial length using the longer eye as the index eye. The postoperative refraction prediction error in 1457 left eyes was assessed in similar axial length groups. RESULTS: The difference in axial length was 0.3 mm or greater in 331 patients (24%). Axial length asymmetry between eyes increased with an increase in axial length in the index eye (P<.001). The 95th centile of the axial length difference was 0.5 mm when the longer eye was 22.0 mm or less and 4.0 mm when it was 28 mm or greater. There was also an increase in postoperative anisometropia with increasing axial length (P = .003). The median was 0.34 D (interquartile range [IR], 0.25‐1.11) when the longer eye had an axial length of less than 28.0 mm and 0.66 D (IR, 0.16‐0.66) when the longer eye had an axial length of 28.0 mm or more. In left eyes, there was an increase in biometry prediction error with an increase in axial length (P = .006). CONCLUSION: An increase in axial length was associated with greater asymmetry between eyes and more postoperative anisometropia, especially in eyes with an axial length greater than 28.0 mm.