Douglas A.M. Lyall

Changes in corneal astigmatism among patients with visually significant cataract

OBJECTIVE To determine the prevalence of corneal astigmatism, changes in astigmatism, and biometry measurements with age and to correlate fellow eye measurements of patients undergoing cataract surgery. DESIGN Prospective, observational study. PARTICIPANTS 3498 eyes of 1814 patients undergoing cataract surgery. METHODS Setting was a single center teaching hospital. Preoperative biometry data measured by partial coherence interferometry (IOLMaster; Carl Zeiss Meditec, Jena, Germany) were collected and analyzed. RESULTS Mean age of the cohort was 74.52 ± 10.23 years. Mean corneal astigmatism was 1.04 ± 0.78 D OD and 1.04 ± 0.79 D OS. About 19.7% and 4.9% of eyes had corneal astigmatism greater than 1.5 and 2.5 D, respectively. The prevalence of against-the-rule astigmatism significantly increased with age bilaterally. Paired fellow eye analysis found a positive correlation for corneal astigmatism, axial length, anterior chamber depth, and white-to-white distance (p < 0.001). About 33.33% of right eyes with corneal astigmatism greater than 2.5 D had more than 2.5 D of astigmatism in the fellow eye. This is in comparison with only 1.5% of right eyes with corneal astigmatism of less than 1.5 D having corneal astigmatism greater than 2.5 D in the fellow eye. CONCLUSIONS Patients with high corneal astigmatism in 1 eye are more likely to have significant astigmatism in the fellow eye. This may necessitate the need for bilateral toric intraocular lens (IOL) implantation during cataract surgery. Against-the-rule astigmatism should be treated more aggressively during cataract surgery, because this is likely to worsen with age. Such information is useful when calculating toric IOL power at the time of surgery.

Changes in ocular monochromatic higher-order aberrations in the aging eye.

Purpose To characterize corneal, internal, and total ocular monochromatic higher-order aberration (MHOA) changes that occur in the aging eye. Methods Prospective observational case series including 300 eyes of 167 patients (mean age = 63.8 years) attending the ophthalmology service at University Hospital Ayr, Scotland. Corneal, internal, and total ocular aberrations were measured over a 6-mm dilated pupil. Zernike coefficients were obtained to the sixth order. Changes in MHOA between age groups and inter-eye correlations between right and left eyes were analyzed. Results A significant inter-eye correlation was found for refractive mean spherical equivalent and cylinder. A significant inter-eye correlation for the whole eye, corneal, and internal MHOA was found (p < 0.001). Right eye analysis found a significant positive correlation between age and the root mean square of whole eye MHOA (p = 0.012), with an increase from 0.517 &mgr;m in the fifth decade to 0.824 &mgr;m in the ninth. Total internal MHOA increased from 0.411 to 0.704 &mgr;m. A significant positive correlation was found between age and internal fourth- (p = 0.007), fifth- (p = 0.029), and sixth-order (p = 0.025) root mean square aberrations. There were no significant age-related changes in corneal MHOA or corneal spherical aberration. Overall mean (SD) corneal SA was 0.203 (0.082) &mgr;m. Conclusions A strong correlation between the right and left eyes exists for MHOA. Whole eye MHOA increases with age. Such changes can be attributed to age-related changes in the internal optical quality of the eye. Such normative data are useful to the cataract surgeon when considering the use of an aspherical IOL to counteract corneal-induced SA during cataract surgery.

Balloon cell naevus of the conjunctiva: clinicopathological features and management.

A 7‐year‐old Caucasian girl presented with a pigmented lesion on the left bulbar conjunctiva that increased in size from 1 mm to 4 mm over a 12‐month period. She underwent excision biopsy and reconstruction of the ocular surface with amniotic membrane graft. Histopathology showed the naevus was composed of somewhat swollen naevus cells with clear cytoplasm and central nucleus. These vacuolated naevus cells were approximately 40 µm in diameter. Over 90% of the cells in the naevus were composed of these swollen cells. Immunohistochemical staining was positive for S100 and Melan‐A. This case illustrates that balloon cells may be observed in conjunctival naevi at a previously unreported pre‐pubescent age. Awareness of ballon cell naevus is important to avoid clinical and histological pitfalls in diagnosis.

Chandelier anterior chamber endoillumination‐assisted phacoemulsification in eyes with corneal opacities

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A Case of Interface Keratitis Following Anterior Lamellar Keratoplasty

Anterior lamellar keratoplasty (ALK) is indicated in patients with anterior corneal opacities. Benefits over penetrating keratoplasty include quicker visual rehabilitation, less postoperative astigmatism, and preservation of the host endothelium, thus minimizing the chances of graft rejection. A rare complication of lamellar corneal surgery is infectious interface keratitis between the donor and host tissue. We report a case of infectious interface keratitis following automated ALK successfully treated medically and by removal of the ALK disk, eventually having a deep anterior lamellar keratoplasty with good visual recovery.

Scleral perforation secondary to a spontaneously dehisced senile scleral plaque: clinical features and management

Senile scleral plaques are common focal calcified deposits located anterior to the insertions of the horizontal recti muscles. Patients are usually asymptomatic and plaques are identified coincidentally on ophthalmic examination. Clinically, they appear as well-demarcated, flat, greyish, oval-shaped opacifications. The diagnosis can be confirmed by computer tomography scanning that shows superficial scleral calcification. Their prevalence increases with age and has been estimated at 22% in patients aged over 80 years. The condition is regarded as benign and requires no active treatment. However, we report a patient who presented following dislodgement of a previously documented plaque revealing a large area of scleral perforation with choroidal show. A 78-year-old Caucasian man presented with ocular discomfort and a ‘black spot’ in the right eye. Past ocular history was significant for bilateral open angle glaucoma, trabeculectomy and previous cataract surgery in the right eye. During earlier visits he was noted to have a senile scleral plaque overlying the insertion of the lateral rectus muscle in the right eye. There was a similar plaque documented overlying insertion of the medial rectus in the left eye (Fig. 1). Past medical history was unremarkable. There was no recent history of trauma. On presentation the best corrected visual acuities were 6/9 in both eyes. Intraocular pressure was 12 and 13 mmHg right and left, respectively, on topical anti-glaucoma therapy. On examination in the right eye there was no scleral plaque at the previously documented site, instead there was a 3 mm-by-5 mm area of scleral perforation and a large area of choroidal ‘show’ at the area of previously noted scleral plaque (Fig. 1). The surrounding episcleral vessels were slightly dilated. The overlying bulbar conjunctiva was absent. Posterior segment examination was normal. Based on the clinical history and signs, a diagnosis of scleral perforation secondary to a spontaneously dehisced scleral plaque was made. Haematological investigations for autoantibodies and inflammatory markers were all within the normal range for his age. Scleral swabs taken for microbiological investigation were negative. After obtaining informed consent the scleral perforation was repaired with a scleral donor patch graft combined with amniotic membrane (AM) transplantation. The surgery was performed under general anaesthesia. Peritomy was not performed as no bulbar conjunctiva was found over the area of perforation. Instead the bulbar conjunctiva was found to be retracted about 4 mm superior to the area of perforation. Under aseptic conditions a disposable 7.5-mm Hanna trephine blade held with an artery clamp was used to mark the scleral bed. Donor sclera obtained with the United Kingdom Transplant eye bank was mounted on a Teflon block and Barron’s disposable corneal punch was used to fashion a 7.5-mm circular patch graft. Devitalized tissue surrounding the area of scleral perforation was carefully dissected with Vanna scissors. The patch graft was placed over the area of the perforation and was secured to the surrounding sclera with multiple interrupted 10-0 nylon sutures. Following this a 2 ¥ 2-cm AM graft was placed basement membrane ‘side up’ over the patch graft and was secured using commercially available fibrin glue (Tisseel, Baxter HealthCare Ltd, Norfolk, UK). Following application of the glue the AM graft was placed over the graft and the edges of the AM were tucked underneath the surrounding bulbar conjunctiva using a paediatric squint hook (Fig. 2). Postoperatively, the eye was treated with topical Ofloxacin (Exocin, Allergan, Goleta, CA) and dexamethasone (Maxidex, Alcon, Fort Worth, TX) four times a day. The topical antibiotic was discontinued after 4 weeks and the topical steroid was gradually tapered over a period of 8 weeks. The amniotic membrane graft was completely absorbed over an 8-week period and the patch graft has remained healthy with overlying conjunctivalization at 6 months follow up. This case highlights an extremely rare complication of a seldom-reported, but common degenerative change found in elderly patients. The underlying aetiology of senile scleral plaques is thought to be secondary to actinic damage caused at the site of insertion of the recti muscles where tractional forces on the sclera are greatest. Clinical recognition is essential as misdiagnosis may result in surgical removal and iatrogenic scleral perforation. Scleral perforation is a rare condition caused by trauma, systemic vasculitis, connective tissue disorders and rarely following ocular surface surgery. Only one previous case of scleral perforation from senile scleral plaque dislocation has been reported. Manschot reported a case where a sclera plaque over the insertion of the medial rectus muscle spontaneously dehisced. However, it is unclear on how the plaque dislodged over an intact bulbar conjunctiva. Our patient may have been predisposed to dehiscence as a result of previous cataract surgery and trabeculectomy. Several natural and synthetic materials have been described to repair a scleral defect. These include fascia lata, periosteum, dermal, scleral and corneal tissue. The use of avascular donor sclera has several benefits. It is strong, avoids the need for graft harvesting in a separate procedure and its avascularity reduces postoperative inflammation. Scleral grafts do not contain epithelium. Therefore, covering the graft with conjunctiva is necessary to prevent graft necrosis. As we were unable to mobilize adequate conjunctiva an AM graft was used. Clinical and Experimental Ophthalmology 2010; 38: 533–538 doi: 10.1111/j.1442-9071.2010.02292.x

Amsler-Verrey sign during cataract surgery in Fuchs heterochromic uveitis

Fuchs heterochromic uveitis (FHU) in its classic presentation is a unilateral, chronic, low grade, often asymptomatic anterior uveitis. It is characterized by a classic triad of iris heterochromia, cataract and keratic precipitates. Neovascularization of the iris and the anterior chamber (AC) angle (radial and circumferential) occurs in 6–22% of cases. This angle and iris new vessels can sometimes lead to a characteristic filiform haemorrhage and formation of hyphaema after AC paracentesis and is a hallmark of FHU known as Amsler–Verrey sign. This haemorrhage has been previously associated with trivial trauma, mydriasis, applanation tonometry, gonioscopy, or it may occur spontaneously. In the setting of cataract surgery it has been previously reported with the use of a Honan balloon. We report a case of cataract and FHU where the Amsler–Verrey sign developed intraoperatively during a phacoemulsification procedure. To the best of our knowledge, this is the first documented report of this sign occurring intraoperatively during cataract surgery.

Unexpected control of a patient's refractory epilepsy when treating glaucoma with acetazolamide

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Limbal stem cell failure secondary to advanced conjunctival squamous cell carcinoma: a clinicopathological case report

A 67-year-old man with a history of multiple myeloma (treated with chemotherapy) was referred with a left hyperaemic conjunctival lesion covering almost 360° of the limbus and extending onto the corneal surface. Conjunctival biopsy revealed conjunctival intraepithelial neoplasia. Initial treatment consisted of topical and intralesional injections of interferon &agr;-2b. The patient subsequently developed limbal stem cell deficiency resulting in a persistent non-healing corneal epithelial defect. This was successfully managed with total excisional biopsy of the lesion, combined with limbal stem cell autograft (from the fellow eye) and amniotic membrane transplantation. Histopathology revealed a conjunctival squamous cell carcinoma. The corneal epithelium completely healed postoperatively and there is no evidence of tumour recurrence at 1 year follow-up. This case highlights a rare case of advanced ocular surface neoplasia causing secondary limbal stem cell deficiency. Medical and surgical management of ocular surface neoplasia with limbal stem cell transplantation is effective in treating such cases.