The application of stereotactic navigation surgery to orbital decompression for thyroid-associated orbitopathy.

OBJECTIVES: To describe the application of stereotactic guidance, its preoperative workup, and limitations, if any, during orbital decompression surgery of the lateral orbital wall for thyroid-associated orbitopathy (TAO). METHODS: Case-controlled series of seven patients who underwent stereotactic-guided surgical navigation during external approach balanced orbital decompression with maximal debulking of the lateral wall. RESULTS: A progressive increase in debulking of the greater wing of sphenoid and exposure of dura was noted in the series. The average proptosis reduction was 9.36 mm. No complications were encountered during any of the cases, nor was there any new onset postoperative diplopia. In all cases, exposure of dura was planned and did not present as a surprise. Stereotactic setup added 10 min to preparation time. CONCLUSIONS: Stereotactic guidance improves anatomic localization and precision during orbital decompression, increasing confidence, and reducing surgical stress. The ability to accurately determine the maximal limits of decompression real time, while confirming depth of bone removal, offers the possibility of reduced risk of iatrogenic injury. Stereotactic navigation allows for improved intraoperative localization that may improve the ability to maximally decompress the lateral wall, including the zygoma, orbital roof, and trigone, and extending towards the optic nerve with exposure of dura through smaller incisions.

Bilateral primary optic nerve lymphoma.

A 69-year-old man was examined for bilateral infiltrative optic neuropathy. Optic nerve biopsy confirmed a malignant B cell lymphoma. Systemic examination and investigations failed to show involvement of other sites.

Age-related maculopathy and cataract surgery outcomes: visual acuity and health-related quality of life.

PURPOSE: To assess visual acuity (VA) and health-related quality of life (HRQoL) outcomes in patients with and without age-related maculopathy (ARM) after cataract surgery. METHODS: Patients aged 60+ years who had undergone cataract surgery at the Westmead Hospital during 2001-2003 were re-examined 1-3 years after surgery. Tests included VA and assessment of visual- and HRQoL using standardised questionnaires (VF-14, SF-12). Preoperative comorbidity data were collected from medical records. Poor surgical outcomes (VA<6/12; no VA improvement; lowest quintile of VF-14, SF-12 scores) were compared in patients with and without ARM, adjusting for age, sex, preoperative systemic comorbidities, ocular comorbidities and surgical or postoperative complications. RESULTS: Of 622 surviving patients, 454 (73%) were followed up for a mean period of 2.8 years. Similar proportions with VA>or=6/12 were observed in patients with (80.2%) and without (88.8%) pre-existing ARM. Preoperative early ARM was only associated with slightly lower mean VF-14 scores (87.64 with vs 92.58 without ARM, P=0.01). Increasing age and preoperative ocular comorbidities were associated with all poor outcomes measured. Low SF-12 scores were associated with preoperative systemic comorbidities. CONCLUSION: Our study documents favourable cataract surgical outcomes 1-3 years after cataract surgery in patients with preoperative ARM.

Early age-related maculopathy in eyes after cataract surgery.

PURPOSE: To assess age-related maculopathy (ARM) in eyes of patients who had undergone cataract surgery for at least a year. METHODS: Consecutive patients aged 60+ years who had undergone cataract surgery at Westmead Hospital, Sydney, Australia, during 2001-2003 were examined in 2004. Interview using standardized questionnaires and stereo retinal photography was performed. Retinal photographs were graded using the Wisconsin ARM grading system. The proportions with ARM were compared between surgical and nonsurgical eyes, and between this surgical cohort and the Blue Mountains Eye Study (BMES) population. RESULTS: Of the 622 eligible patients, 454 (73%) were re-examined, with a mean follow-period of 2.8 years. Surgical eyes had a higher proportion of early ARM compared to nonsurgical eyes (15.2 vs10.3%, P=0.07) and to the early ARM prevalence found in BMES participants of similar age (14.5 vs6.9%, P<0.01), which persisted after age standardization to the BMES population (9.7 vs6.9%, P<0.05). CONCLUSIONS: We found an increased prevalence of early ARM in surgical eyes of patients 1-3 years after cataract surgery. Whether this increased early ARM prevalence leads to an increased prevalence of late ARM in the long-term warrants further investigation.

Effects of lamellar keratotomy on postkeratoplasty astigmatism.

AIM: To determine the changes in postkeratoplasty astigmatism induced by lamellar keratotomy. METHODS: A prospective, non-randomised comparative trial of patients undergoing a hinged lamellar corneal flap for treatment of significant astigmatism after penetrating keratoplasty. Uncorrected visual acuity, best corrected visual acuity, refraction, and corneal topography were assessed at 1 and 3 months after the lamellar keratotomy. RESULTS: 17 eyes in 16 patients (13 M, 3F) were included in the study (mean age 48.2 years; range 20-86 years). Six of 17 eyes (35.3%) changed more than 1 dioptre (D) in spherical equivalent by 3 months. Nine of 17 eyes (52.9%) changed more than 1 D in sphere by 3 months. 12 of 17 eyes (70.6%) changed more than 1 D in refractive cylinder. Seven patients of 15 (46.7%) changed more than 1 D in corneal power as measured topographically. Five of 17 eyes (29.4%) changed in refractive cylinder axis more than 15 degrees and this was similar to the change measured topographically of four of 15 eyes (26.7%). Vector analysis showed 60% of eyes had a surgically induced astigmatism (SIA) vector of more than 1 D, including a net corneal astigmatism decrease of more than 1 D in four eyes and increase of more than 1 D in two eyes at 3 months after surgery. Complications of the lamellar keratotomy included two partial buttonholes and one partial wound dehiscence. CONCLUSIONS: The creation of a lamellar flap alone can have significant effects on the astigmatism following penetrating keratoplasty. LASIK for correction of postkeratoplasty astigmatism may be more accurately performed as a two stage procedure rather than a single stage, after the corneal effects of the lamellar keratotomy have stabilised.

Medpor porous polyethylene implants in orbital blowout fracture repair.

PURPOSE: Various materials are used in orbital blowout fracture repair. We describe a series of patients with orbital blowout fractures that were repaired using porous polyethylene (Medpor) sheets. METHODS: A non-comparative interventional case series is described of 30 blowout fractures of 30 patients aged 7-60 years (median 29 years) who underwent orbital blowout fracture repair with Medpor sheets. The mean follow-up was 19.1 months (minimum 5 months). The indication for surgery in 6 cases was non-resolving diplopia. The remaining 24 cases had surgery for enophthalmos. Ten cases underwent primary or secondary hydroxyapatite orbital implantation at the same time as orbital floor blowout fracture repair. Data were collected on postoperative motility and diplopia, enophthalmos, cosmesis, complications and re-operations. RESULTS: In no case was diplopia worsened by blowout fracture repair. Where surgery was performed for the correction of enophthalmos, late surgery did not compromise the surgical results. There were no intraoperative complications. The one major complication was a case of recurrent implant infections leading to implant removal. There were 3 minor postoperative complications: 2 cases of postoperative infraorbital anaesthesia and one case of a palpable titanium screw. Re-operations were performed for pre-existent diplopia, lid laxity, socket abnormalities and mid-facial deformities. None of these arose from the blowout fracture repair. CONCLUSIONS: The study suggests that in orbital blowout fracture repair Medpor implants are safe and effective with few complications. Late surgery for enophthalmos is technically more difficult but is not associated with poorer functional or cosmetic results.

Necrotising orbital cellulitis.

PURPOSE: To report 2 cases of severe necrotising orbital cellulitis which illustrate the need for aggressive surgical management to prevent blindness. METHODS: The case records of 2 patients with necrotising orbital cellulitis were reviewed. RESULTS: Both patients had orbital cellulitis associated with sinusitis. Each case was characterised by the rapid development of severe systemic toxicity, extensive soft tissue necrosis and abscess formation. One patient developed panophthalmitis and the eye had to be eviscerated. The other patient underwent repeated surgical drainage of multiple orbital abscesses. This led to resolution of the infection and preservation of vision. CONCLUSIONS: Atypical rapidly progressive necrotising orbital cellulitis may occasionally be encountered. In such cases, aggressive surgical drainage of orbital abscesses is crucial to prevent blindness and death.

The maximal Hughes procedure.

PURPOSE: To describe the use of oblique medial and lateral periosteal flaps with the Hughes tarsoconjunctival flap for the repair of maximal defects of the lower eyelid. METHODS: A small prospective case series of eight patients requiring lower eyelid reconstruction following with maximal defect of the lower eyelid. The patients underwent a Hughes tarsoconjunctival advancement combined with oblique medial and lateral periosteal flaps, and were assessed for aesthetic outcome and surgical complications. RESULTS: All patients had uncomplicated surgery. Outcomes assessed included corneal protection, eye closure, lower eyelid retraction, complications, and patient satisfaction. Eyelid contour and protection was excellent in all patients. Postoperatively, one patient had mild lower eyelid retraction, and in a second patient, medial ectropion with mild lower eyelid retraction developed that required subsequent revision. CONCLUSIONS: The maximal Hughes procedure is a safe and effective procedure that may be performed with patients under local anesthesia and may avoid the need for more extensive techniques for surgical repair of maximal defects of the lower eyelid.

Silicone intraocular lens compression and double lens implants in diseased eyes.

PURPOSE: To assess the outcomes of double lens implants in hyperoptic eyes with associated pathology. METHOD: Double lens implants were used in 4 eyes of 4 patients each with a different ophthalmic or neuro-ophthalmic disease. Biometry was performed in the standard contact fashion and lens power formulae used included SRK/T, Holladay and Hoffer Q. RESULTS: Average spherical equivalent refraction improved from +6.875 D to +0.38 D. Absolute average prediction error was greatest for SRK/T (2.65 D) and least for Holladay (1.73 D). Refractive suprises were influenced by the underlying disease process. One patient showed central lens compression. CONCLUSION: Underlying disease can produce biometry errors. Structural ophthalmic or neurological disease is not a contraindication to the use of double lens implants. Double lens implants are useful to correct refractive error in the presence of underlying disease.

The glabellar flap dissected.

The glabellar flap is effective in the reconstruction of defects within the medial canthal region. The unique contour of the medial canthal region presents a challenge in the surgical planning of the glabellar flap, which is only briefly described in texts. We describe its step by step construction, including the indications and precautions. We also include a section on variations in design for improved closure. With careful planning, the glabellar flap provides excellent cosmetic results.

Reliable keratometry with a new hand held surgical keratometer: calibration of the keratoscopic astigmatic ruler.

AIM: Some surgeons consider hand held surgical keratometers unreliable. This may be due to incorrect use through not realising that the distance that the keratometer is held from the cornea influences the shape of the image. When a keratometer is held closer to the astigmatic cornea, the elliptical image will appear more circular, particularly for larger degrees of astigmatism. However, the keratoscopic astigmatic ruler (KAR) has design features that correct the hitherto unrecognised problems with the use of a hand held keratometer. This study assesses the reliability and accuracy of measurement of astigmatism using the KAR. METHODS: The KAR and the Bausch & Lomb keratometer (B&L) were compared using six back surface toric cut contact lens blanks representing 1 to 6 dioptres of astigmatism. Two observers (one experienced in the use of the keratometers, the other a novice) took eight randomly repeated "masked" measurements of each lens blank with the KAR and four measurements with the B&L in a similar fashion. RESULTS: There was no difference between the measurements with either instrument by each of the observers (p = 0.95, ANOVA). The standard error of measurement for the KAR was 0.59 D, for the B&L, 0.31 D. The intraclass correlation coefficient of reliability for the KAR was 0.90 and for the B&L it was 0.97. The coefficient of repeatability for the KAR was plus or minus 0.83 D, and for the B&L plus or minus 0.77 D. The interobserver reliability for the KAR was 0.898, and for the B&L, 0.975. CONCLUSION: These results suggest that the KAR has good reliability and reproducibility and compares favourably with the B&L keratometer. Inexperience with use does not affect reliability.

Influence of corneal shape on limbal light focusing.

PURPOSE: Light incident at the temporal cornea is focused by the peripheral anterior eye to the nasal limbus, the usual site of pterygium formation. Parameters that may contribute to observed individual variations in the degree of limbal light focusing were assessed. METHODS: Computer-assisted optical ray tracing techniques were applied to a human anterior segment model. The angle of incident light (theta, 95 degrees to 108 degrees posterior to the sagittal plane), corneal central radius of curvature (ro, 7.2 to 8.4 mm), and shape factor (p) were varied, and the effect on distal limbal intensity (I) was calculated. RESULTS: The magnitude of intensity peaks (Ipeak) is dependent on theta and ro. Steeper corneas have higher intensity peaks (Ipeak approximately 21.5X at ro = 7.2 mm, p = 0.75), and flatter corneas have lower intensity peaks (Ipeak approximately 8X at ro = 8.4 mm, p = 0.75) (cf Ipeak approximately 14X for a standard cornea, ro = 7.8 mm, p = 0.75). Anteroposterior location of intensity peaks is dependent on theta and ro. Steeper corneas have intensity peaks situated more anteriorly, whereas flatter corneas have more posteriorly placed peaks. Distal light distribution profiles demonstrate that intensity peaks are not always centrally located. At lower angles of incidence (theta = 100 degrees, ro = 7.8 mm, p = 0.75), peak intensity is located approximately 1 mm above and below the horizontal plane. The overall distribution (envelope) of light at the distal limbus is apparently independent of corneal shape. CONCLUSIONS: Differences in corneal topography can account for the clinical observation of individual variation in the degree of limbal light focusing. Whether individuals with corneas capable of developing intense limbal foci may be more predisposed to developing pterygium requires further study.

Effect of topical interferon-alpha 2b on corneal haze after excimer laser photorefractive keratectomy in rabbits.

BACKGROUND: Anterior corneal stromal keratocytes are activated by excimer laser photorefractive keratectomy resulting in haze with healing of the ablated area. In some eyes, this causes a visible haze or scar on the cornea, and an unpredictable regression of the myopic correction following refractive ablations. METHODS: Following a 6.00-diopter excimer laser photorefractive keratectomy to both eyes, 16 rabbits were treated for 5 weeks with interferon-alpha 2b drops four times a day to one eye only. Eight of these rabbits were treated with dexamethasone drops four times a day to both eyes. Using a standard grading scale for haze, the corneas were examined and the haze graded weekly. RESULTS: The observed corneal haze was significantly reduced in the treated eyes by the application of topical interferon-alpha 2b drops (p = .004), and topical dexamethasone drops (p < .001). Topical dexamethasone also produced less haze in combination with interferon-alpha 2b than when used alone (p = .035). There was continuing resolution of the corneal haze in those rabbits observed for 7 weeks after the cessation of the drops. Topical interferon-alpha therapy was not toxic to the rabbit eye and was not associated with delayed reepithelialization after the laser procedure. CONCLUSION: Topical interferon-alpha 2b appears to reduce the corneal haze produced by excimer laser photorefractive keratectomy in rabbits.