BACKGROUND:

The propose of this study was to analyze the relationship between retinal nerve fibre layer (RNFL) thickness measured by spectral domain optical coherence tomography and confocal scanning laser ophthalmoscope.

DESIGN:

Prospective, cross-sectional study. Hospital setting.

PARTICIPANTS:

One hundred seventy-three subjects (85 glaucoma and 88 normal subjects).

METHODS:

One eye from each individual was selected randomly for RNFLT imaging by the spectral domain Cirrus OCT and HRT3.

MAIN OUTCOME MEASURES:

Global RNFL thickness and measurements at the four quadrants around the optic disc were analyzed and compared for differences, agreement of the categorical classification, diagnostic sensitivities and specificities and the area under the receiver operating characteristic curves (AUC).

RESULTS:

RNFL thickness as determined by HRT3 were significantly thicker than measurements done by Cirrus OCT (respectively in μm, for global thickness: 200.0±87.2 and 80.7±14.7, for temporal quadrant: 75.3±31.9 and 59.1±13.8, for superior quadrant 223.2±128.4 and 97.7±20.9, for nasal quadrant 208.0±102.9 and 66.8±11.8, and for inferior quadrant 224.4±116.9 and 99.1±26.6, for all P<0.01). Significant correlation was found for all measurements (P≤0.009) but a pattern of proportional bias was demonstrated. The agreement of categorical classification for RNFL thickness (within normal limits, borderline, or outside normal limits) ranged between poor to fair.

CONCLUSIONS:

RNFL thickness measurements by Cirrus OCT and HRT3 are strongly correlated but significantly different. The differences between paired RNFL measurements are substantial and proportional to the RNFL thickness. The normative diagnostic classification of the 2 technologies may not agree. The results preclude interchangeable use of these measurements in clinical practice.

Decreased microcirculation of the optic nerve, among other factors including high intraocular pressure (IOP), senescence, and myopia, may contribute to optic nerve damage and lead to the progression of glaucoma. Unfortunately, it is not easy to quantify decreased microcirculation. Historically, it has been associated with the area of filling defects of the optic disc (FD) measured with fluorescein angiography (FA).(1) However, FA examination is invasive, the injection of fluorescein can cause severe complications, such as anaphylactic shock, and the results can be affected by time-dependent changes. Recent innovations in laser speckle flowgraphy (LSFG) have allowed us to monitor changes in the mean blur rate (MBR) of tissue circulation over time, including after pharmacological intervention, at the same site and in the same eye.(2) Furthermore, MBR is correlated with absolute blood flow values measured with hydrogen gas clearance or microspheres.(3, 4) Although it is relative, therefore, MBR should be comparable between eyes. Recently, automatic threshold adjustment allows LSFG to create grayscale images and divide the optic disc into vessel and tissue regions. To determine the comparability of FA and LSFG, we determined the correlation of the relative areas of FD and the region in the optic disc with low circulation density (LD) measured with LSFG to mean deviation (MD) from standard automated perimetry (SAP).

An 18-year-old boy experienced fatigue and developed jaundice of unknown aetiology five years ago, and he was diagnosed with and treated for haemolytic anaemia. In December 2011, he visited an ophthalmologist for blurred vision in the right eye. Visual acuity (VA) of the right and left eyes was 6/12 and 6/6 respectively, and the intraocular pressure (IOP) of each was 53 and 17 mmHg respectively. Prominent Kayser-Fleischer (KF) rings were detected in both eyes. Laboratory tests revealed normal serum copper (362.4 μg/L), low serum ceruloplasmin (56 mg/L), and very high 24-hour urinary copper excretion (1765.6 μg). Magnetic resonance imaging of the brain showed high signal intensity changes in the pons and the left thalamus. The diagnosis of Wilson disease was confirmed via a positive genetic test result for mutation in the ATP7B gene. The patient was placed on a low copper diet and administered D-penicillamine, hepatoprotective drugs, and antiglaucomatous medications. However, he complained that his vision was substantially reduced in his right eye. When the patient visited us, the VA of the right eye was hand motion and that of the left was 6/6 with correction. The IOP was 44 mmHg in the right eye and 15 mmHg in the left eye. His corneas were transparent, and KF rings were clearly evident in both. Both eyes exhibited a golden-brown ring located in the peripheral cornea and the anterior lens surfaces (see Figure 1 A, B). The optic nerve head was pale and the cup-to-disc (CD) ratio was almost 0.8 in the right eye. The optic nerve head was normal and the CD ratio was 0.4 in the left eye. Gonioscopy revealed that the anterior chamber angles of both eyes were wide and open; however, a thick layer of yellow-grey material covered the trabecular meshwork in the right eye (Figure 1 C), which was not evident in the left eye.

Neoplastic involvement of extraocular muscles (EOMs) may be the result of a primary muscle tumor, local infiltration from an orbital tumor, or metastasis from a distant site. Metastases to the EOMs are uncommon and are most frequently associated with breast cancer and melanoma.(1) In this report, we describe a case of parameningeal alveolar rhabdomyosarcoma with metastases to all EOMs. A 29-year-old Hispanic female presented for evaluation of eye pain of 2 days duration. The patient was previously diagnosed with metastatic rhabdomyosarcoma in June 2011 after presenting with right-sided proptosis and vision loss. Magnetic resonance imaging (MRI) at that time showed a primary lesion in the right ethmoid sinus with intraorbital and intracranial extension. An intranasal biopsy confirmed alveolar rhabdomyosarcoma. There was no evidence of EOM involvement, and motility was full OU. Her visual complaints were felt to be secondary to compressive optic neuropathy. Positron emission tomography (PET) showed metastases to bone, bone marrow, lymph nodes, and soft tissues. Vision and proptosis improved following radiation and chemotherapy, and she achieved remission despite undergoing a shortened course of chemotherapy due to myelosuppression.

Conjunctivodacryocystorhinostomy (CDCR) with the insertion of a Lester-Jones tube (LJT) is used in the management of non-reconstructible lacrimal canalicular obstruction. Surgical success rates following CDCR and LJT are over 90%. However complications relating to LJT malposition are common. (1) We present a previously unreported complication of periorbital emphysema following LJT insertion. A 61-year-old man had a left LJT (Altomed, Tyne and Wear, UK) inserted for epiphora due to proximal lacrimal obstruction. The patient had previously undergone three failed external dacryocystorhinostomy procedures. Post operatively the external end of the LJT was noted to be sitting in the region of the inferior part of the caruncle. For the first seven days following the procedure the patient reported a complete resolution of left sided epiphora. Unfortunately the patient misunderstood the post-operative instructions and instead of sniffing eye drops down the tube, he deliberately blew air up the tube. On day eight the patient presented with left sided orbital pain, associated with periorbital swelling and epiphora.

We report a case of cystoid macular oedema (CMO) precipitated by selective laser trabeculoplasty (SLT) performed to treat steroid-induced ocular hypertension in a diabetic patient. A 47-year-old diabetic male complained of blurred vision in the right eye. The right visual acuity (VA) was 6/9 and the intraocular pressure (IOP) was 16 mm Hg. Examination revealed bilateral moderate non-proliferative diabetic retinopathy and right clinically significant macular oedema (CSMO), also evident on optical coherence tomography (OCT) scanning. Fluorescein angiography demonstrated multiple leaking perifoveal microaneurysms which were too close to the foveal centre to be treated safely with focal laser photocoagulation. A right posterior sub-Tenon triamcinolone injection (40 mg in 1 ml) was administered. Four weeks later, the right VA had improved to 6/7.5, associated with almost complete resolution of macular thickening on OCT. However, the right IOP had risen to 24 mm Hg. Topical brinzolamide 10 mg/mL and timolol 5 mg/mL twice daily was prescribed. Seven months after the triamcinolone injection, the right VA had improved to 6/6, though OCT demonstrated mild recurrent CMO (Figure 1). The right IOP was now 37 mm Hg despite continued topical treatment. Consequently, right SLT was performed, with 100 x 0.9 mJ shots divided evenly over the entire angle circumference. Seven days following SLT, the right IOP had fallen to 16 mm Hg, but the patient reported that a marked deterioration in right vision had developed within 12 hours of the SLT being performed. The best corrected right VA was now 6/18, associated with marked macular oedema on OCT scanning (Figure 2). Topical ketorolac trometamol 5mg/ml (Allergan Australia Pty Ltd) four times a day for eight weeks and dexamethasone 1mg/ml (Alcon Laboratories, Australia Pty Ltd) four times a day for two weeks was prescribed. A gradual improvement in VA to 6/9 and reduction in CMO occurred during the subsequent eight weeks.

A 64-year-old man with Marfan's syndrome was referred with ectopia lentis and visual acuity (VA) of 6/12 bilaterally. He had a history of right BRVO, aortic aneurysm stenting and multiple TIAs and was on warfarin and clopidogrel. He was listed for a right vitreolensectomy. Overnight, however, he had severe left eye pain and vomiting that gradually resolved. On examination, his VA was 6/60 and his pupil was mid-dilated. The cornea was oedematous (figure 1) but his intraocular pressure (IOP) was 14mmHg. He was given pilocarpine drops and listed for a left vitreolensectomy. However, he presented again with an IOP of 48mmHg and a pupil-captured crystalline lens (figure 2). His IOP was successfully controlled medically with intravenous Mannitol, acetazolamide and topical hypotensives, and an Nd-YAG iridotomy was arranged to prevent further episodes. However, upon corneal indentation during gonioscopy the lens relocated to the posterior chamber. The iridotomy was completed and the patient suffered no further acute angle closure episodes. He underwent vitreolensectomy and anterior chamber lens implantation in both eyes. Postoperatively, his best corrected VA was 6/6 and IOP was 18 mmHg.

BACKGROUND:

To compare the accuracy of the Pentacam Scheimpflug device Holladay equivalent keratometry readings with the IOL Master 500 keratometry in calculating intraocular lens power in normal eyes having cataract surgery

DESIGN:

Non-randomised, prospective clinical study conducted in private practice

PARTICIPANTS:

Forty-five consecutive normal patients undergoing cataract surgery

METHODS:

Forty-five consecutive patients had Pentacam equivalent keratometry readings at the 2mm, 3mm and 4.5mm corneal zone and IOL Master keratometry measurements prior to phacoemulsification and in-the-bag intraocular lens implantation. After constant optimisation, the expected refractive error was calculated for each Pentacam EKR zone and IOL Master measurement using the Holladay 2 and SRKT formulas. Four weeks following surgery the difference between the observed and expected refractive error was calculated.

MAIN OUTCOME MEASURE:

Mean keratometric value and mean absolute refractive error

RESULTS:

There was a statistically significantly difference between the mean keratometric values of the IOL Master, Pentacam EKR2mm, 3mm and 4.5mm measurements (p<0.0001, ANOVA). There was no statistically significant difference between the mean absolute refraction error (MAE) of the IOL Master, EKR2mm, EKR3mm and EKR4.5mm for either the Holladay 2 formula (p-=0.14) or SRKT formula (p=0.47). The MAE for Holladay 2 was lowest for the IOL Master with the lowest SD (mean 0.21D+/- 0.15D) and the next lowest was the EKR4.5mm (mean 0.25D +/- 0.17D). The MAE for SRKT was lowest for the IOL Master (0.19D +/- 0.13D) and next lowest was the EKR 4.5 mm (mean 0.25D+/- 0.19D). Comparing the absolute refraction error of IOL Master and Pentacam EKR, best agreement was with Holladay 2 and EKR4.5mm, with mean of the difference of 0.02D and 95% LOA of -0.35D and 0.39D

CONCLUSIONS:

The IOL Master keratometry and Pentacam EKR were not equivalent when used only for corneal power measurements. However, the keratometry measurements of the IOL Master and Pentacam EKR4.5mm may be similarly effective when used in intraocular lens power calculation formulas, following constant optimisation.