Refractive lens exchange in high myopia: long term follow up.

AIM: To establish long term outcomes and incidence of complications following refractive lens exchange (RLE) for the correction of high myopia. METHODS: Operative and postoperative records of 62 cases of small incision phacoemulsification RLE performed in 37 patients over an 11 year period, by a single surgeon, were reviewed. In addition, patients were recalled for a follow up examination, which included dilated retinal examination with scleral indentation. RESULTS: Two cases (3.2%) of retinal detachment occurred at intervals of 2 months and 5 months following uncomplicated RLE procedures. A posterior chamber intraocular lens was inserted in 46 eyes (74%). YAG laser posterior capsulotomy was performed in 38 of 62 eyes (61%) and did not represent a risk for retinal detachment. CONCLUSION: Refractive lens exchange results in rapid and predictable improvement in unaided vision in patients with high myopia. However, the risks of sight threatening complications inherent in any intraocular procedure underlie the need for appropriate patient selection.

Myopic and hyperopic laser in situ keratomileusis retreatments: indications, techniques, limitations, and results.

PURPOSE: To assess the efficacy of myopic and hyperopic laser in situ keratomileusis (LASIK) retreatment procedures. SETTING: Mater Private Hospital, Dublin, Ireland. METHODS: Retreatment was defined as either lifting the previously created flap or when this was not possible, cutting a new flap. Fifty-six patients were retreated, 17 with hyperopia (Group 1) and 39 with myopia (Group 2). The mean preoperative spherical equivalent in Group 1 was +3.79 diopters (D) +/- 1.53 (SD) (range +1.75 to +8.12 D) and in Group 2, -5.46 +/- 2.87 D (range -0.38 to -15.25 D). RESULTS: The indications for retreatment were undercorrection, decentration, epithelial ingrowth, and central island. Postoperatively, the mean spherical equivalents in Groups 1 and 2 were +1.11 +/- 2.02 D (range -1.75 to +5.50 D) and -1.02 +/- 2.20 D (range +4.75 to -9.00 D), respectively. In Group 1, the uncorrected visual acuity (UCVA) was 6/12 or better in 5.8% preoperatively and in 35% postoperatively. In Group 2, the UCVA was 6/12 or better in 5.1% preoperatively and in 59.0% postoperatively. Although 29% of the hyperopic eyes and 8% of the myopic eyes lost 1 Snellen line of best corrected visual acuity (BCVA), there was an improvement (of 1 or more lines) in BCVA in 12% and 49%, respectively. In cases that were decentered preoperatively, the postoperative optical zone ablation centration was better in 85.7% of Group 1 eyes and 61.5% of Group 2 eyes. Corneal complications following retreatment included peripheral scarring, epithelial ingrowth, Bowman's folds, and keratectasia. CONCLUSIONS: Both myopic and hyperopic retreatments resulted in a stable refractive outcome. Myopic retreatments were superior to hyperopic retreatments in both efficacy and safety.

Double blind, randomised, placebo controlled, crossover, multicentre study to determine the efficacy of a 0.1% (w/v) sodium hyaluronate solution (Fermavisc) in the treatment of dry eye syndrome.

BACKGROUND/AIMS: Hyaluronan (sodium hyaluronate) has been shown to confer objective and subjective improvement in patients with dry eye syndrome. This study compared the efficacy and safety of a 0.1% solution of hyaluronan with 0.9% saline, when administered topically to the eye, in the treatment of symptoms of severe dry eye syndrome. METHODS: A randomised, double blind, crossover clinical trial in which subjects were randomised to receive either hyaluronan or saline, applied as one or two drops to the eye, three or four times a day or as required. After 28 days' treatment, subjects crossed over to the other study medication for a further 28 days' treatment. RESULTS: 70 subjects were included in the analyses of efficacy and significant improvements in Schirmer's score (p=0.0006) and rose bengal staining score (p=0.0001) were observed during treatment with hyaluronan. In a subjective assessment of the effectiveness of two treatments, a majority of subjects felt that hyaluronan was more effective than saline in alleviating the symptoms of burning and grittiness (p<0.001). No adverse events attributable to hyaluronan treatment were reported. CONCLUSION: The study demonstrates a clear benefit of hyaluronan over saline, in both subjective and objective assessments of dry eye syndrome. Hyaluronan was shown to be well tolerated.

Endophthalmitis after astigmatic myopic laser in situ keratomileusis.

A 36-year-old woman had uneventful astigmatic myopic laser in situ keratomileusis (LASIK) to correct -12.00 -1.50 x 70. Three days later, she developed a corneal abscess, hypopyon, and an intense vitreous cellular reaction-endophthalmitis. The patient was immediately given intravenous ciprofloxacin and topical vancomycin and ceftazidime. The infecting organism was Streptococcus pneumoniae. One day after therapy was instituted, the hypopyon resolved. Seven months later, best corrected visual acuity was 20/25 and refractive error, -4.00 diopters. A stromal scar (grade 2 haze) was causing a slight reduction in acuity. Endophthalmitis after LASIK, if treated promptly, need not lead to a permanent reduction in visual acuity.

Topographical analysis of ablation centration after excimer laser photorefractive keratectomy and laser in situ keratomileusis for high myopia.

PURPOSE: To evaluate the ablation centration after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for high myopia and to assess the association between decentration and best corrected visual acuity (BCVA), glare, monocular diplopia, and halo phenomenon. SETTING: Mater Private Hospital, Dublin, Ireland. METHODS: Corneal topography was used to analyze centration in two groups of patients with myopia of more than 6.0 diopters: 18 had PRK and 18, LASIK. A standardized questionnaire assessed the preoperative and postoperative prevalence of glare, monocular diplopia, and halo phenomenon. RESULTS: "Significant" ablation decentration (0.5 mm) in the LASIK group (1.33 mm) was almost twice that in the PRK group (0.75 mm). Glare increased from 27% preoperatively to 42% in the PRK group; monocular diplopia increased in the LASIK group. Halo phenomenon decreased after both procedures. CONCLUSION: Laser in situ keratomileusis represents a step forward in the surgical correction of high myopia, but the accuracy of the corneal ablation location must be improved. Suction ring fixation of the globe or real time tracking systems may help improve centration.

Laser intrastromal keratomileusis for high myopia and myopic astigmatism.

BACKGROUND: Laser intrastromal keratomileusis (LASIK) is an evolving technique which enables high degrees of myopia (> 8.0 dioptres) and myopic astigmatism to be corrected. This paper describes initial experience with this procedure. It also details the methodology, the results, the problems encountered, and discusses retreatment procedures. METHODS: 51 eyes (48 primary cases and three retreatments) underwent LASIK for simple myopia or compound myopic astigmatism. After the keratotomy was fashioned with a Chiron corneal shaper, the ablation was performed with either a Summit or Meditec excimer laser. The actual preoperative astigmatism ranged from -0.5 D to -6.0 D (in the astigmatic myopic LASIK (AML) series), while the range of preoperative myopia in the combined myopic LASIK (ML) and AML series was -8.0 D to -37.0 D. Of the ML cases, group 1 (-8.0 to 15.0 D (dioptres)), group 2 (> -15.0 to -20.0 D), and group 3 (> -20.0 D) had mean preoperative myopia values (spherical equivalent) of -11.26 D, -16.84 D and -27.78 D. The same groupings (1, 2, and 3) for the AML cases had respective values of -9.702, -17.4, and -23.08. In the AML series the mean preoperative astigmatism was -2.109 D. Follow up ranged from 8 to 27 months (mean 15.8 months). Six of the cases required retreatment. RESULTS: There was a reduction in best corrected visual acuity (BCVA) (of 1 Snellen line) in seven of the primary cases (14.5%) (three in the ML group and four in the AML group), and in one of the retreatment cases. The BCVA improved in 28 cases (58%) in the primary treatment group. The mean correction attempted (spherical equivalent) for the ML groups 1, 2, and 3 was 10.51 D, -14.5 D, and -27.78 D, versus a mean correction achieved of -9.445 D, -15.625 D, and -21.571 D. Similarly, for the AML groups, attempted correction values were -9.702 D, -17.4 D, and -23.08 D, while the values achieved were -6.95 D, -51.425 D, and -15.708 D. Regression was minimal and stabilisation of the refractive result was achieved in all groups, except group 3 of the ML series, by the 3 month examination period. The mean postoperative astigmatism in the AML series was -0.531 D. Vector analysis of the AML series showed that the mean surgically induced astigmatism was +0.93 D. The most common complication encountered was undercorrection, which occurred in 35 cases-23 cases in the ML group and 12 cases in the AML series. Twenty eight per cent of the ML cases, and 25% of the AML cases were within plus or minus 1.5 D of the attempted refraction. CONCLUSION: For the correction of high myopia and myopic astigmatism, LASIK results in less postoperative pain and relatively little subepithelial haze compared with high myopic photorefractive keratectomy. Furthermore, a stable refraction and reasonably predictable outcome occurs much earlier. High myopia up to -37.0 D can be corrected, albeit with some limitations at the extremes of myopia-in terms of the amount of myopia correctable; this represents a limitation of the technique. Retreatment is a technically straightforward and effective way to treat undercorrection. Undercorrection, the main complication seen in our series, should become less common when the ablation algorithms are further refined.

Results of the intercapsular technique with the IOGEL lens.

Standard biconvex 12 mm diameter IOGEL PC-1 hydrogel intraocular lenses were inserted into the eyes of 55 patients using intercapsular in-the-bag placement and extracapsular ciliary sulcus placement. All patients had senile cataracts. Endothelial specular microscopic assessment was performed preoperatively and postoperatively at six and 12 months. Viscoelastic agents were not used in any of the cases and upper haptic positioning was achieved with dialing and irrigation and iris retraction in each group, respectively. Major complications in both groups were iridocapsular synechias. This resulted in dislocation of a single haptic into the anterior chamber angle in one ciliary-sulcus-placed lens and in an updrawn pupil in one of the intercapsular cases. Pigment dispersion syndrome occurred in one case with a ciliary-sulcus-placed lens. In one case in each group a Nd:YAG laser posterior capsulotomy was performed. Whereas the visual results in each group were similar, the percentage cell loss was significantly greater in the group with lenses in the ciliary sulcus at six months postoperatively. The lower cell loss in the intercapsular group was attributed to the protective effect of the anterior capsule on the endothelium during the major intraocular manipulations.

Patterns of visual loss in untreated sickle cell retinopathy.

Ophthalmic assessments of 120 patients with homozygous sickle cell (SS) disease and of 222 with sickle cell haemoglobin-C (SC) disease were conducted over a period of ten years. Visual acuity loss (V.A. less than or equal to 6/18) attributable to sickle cell retinopathy occurred in 10% of untreated eyes during a mean observation period of 6.9 years. Visual loss was strongly associated with proliferative sickle retinopathy (p less than 0.001) and most commonly resulted from vitreous haemorrhage, tractional retinal detachment and epiretinal membranes. The incidence of visual loss was 31 per 1000 eye-years observation among eyes with proliferative disease compared to 1.4 per 1000 eye-years observation among eyes with non-proliferative disease.

Hydrogel intraocular lens experience with endocapsular implantation.

The experience is presented of three independent surgeons using Hydrogel posterior chamber intraocular lenses in a combined series of 157 endocapsular cataract extractions. One hundred and fifty of these eyes were examined after a minimum follow-up period of one year and 92.0% achieved visual acuity of 6/12 or better, and 98.6% achieved this if pre-existing pathology was excluded. Insertion of this lens has proved to be simple, the adaptions of technique required are described and the complications are presented and analysed.

Recurrent visual loss in homozygous sickle cell disease.

In sickle cell retinopathy vascular involvement is most frequently recognised at the retinal periphery, but obstruction of perimacular arterioles and of major retinal vessels may also occur. This report describes a patient with homozygous sickle cell (SS) disease with recurrent occlusion of major retinal vessels associated with recurring transient impairment of visual function.

Pseudophaco--anaphylactic endophthalmitis? P.M.M.A. related.

The pathological findings of pseudophacoanaphylactic endophthalmitis are described in a patient with a combined trabeculectomy, extracapsular cataract extraction and an "in-the-bag" posterior chamber lens implant, and who developed sympathetic ophthalmitis following a perforating eye injury within hours of his operation. Apart from the typical sympathetic histological findings, the eye revealed a pseudophaco-anaphylactic endophthalmitis reaction which appeared to be totally related to the polymethylmethacrylate (P.M.M.A.) optic. The "in-the-bag" polypropylene closed loops revealed no significant histological reaction.

Successful intraocular lens implantation: a histological and scanning electron microscopic study of four cases.

The histological findings in four globes obtained at autopsy from clinically uncomplicated cases with intraocular lens implants, one glass posterior chamber and three anterior chamber lenses consisting of two pupillary fixated and one "in-the-bag" fixated Binkhorst lens, are reported. Minimal changes could be detected in the tissues with which the implants were in contact. Scanning electron microscopy of the cornea in the three anterior chamber implants showed a loss of endothelial cells in the axial region of roughly 30-50%. There was marked vertical disparity in the loss. Scanning microscopy of the implants showed evidence of surface degradation of the nylon loops of all the anterior chamber implants.

Blood rheology and proliferative retinopathy in sickle cell-haemoglobin C disease.

Haematological and rheological (plasma and serum viscosity, whole blood viscosity, and erythrocyte filterability) factors were studied in 31 age-sex matched pairs of patients with sickle cell haemoglobin C disease with and without proliferative sickle retinopathy (PSR). Patients with PSR had significantly higher mean cell haemoglobin and lower Hb F levels on average than the matched controls, but the viscosity and erythrocyte filtration indices did not differ between the 2 groups. There was, therefore, no evidence of rheological differences between patients with and without PSR at the time of the study, although transient rheological abnormalities at the time of development of PSR could not be excluded. Prospective longitudinal studies of rheology before, during, and after the development of PSR would be necessary to detect such changes.

Alpha thalassaemia and the macular vasculature in homozygous sickle cell disease.

The interaction of homozygous alpha thalassaemia 2 with homozygous sickle cell (SS) disease results in a generally milder haematological picture with less intravascular sickling, less haemolysis, and higher haemoglobin levels. Clinically, patients are generally more mildly affected, though not all vaso-occlusive complications are reduced. Thus there is a possibility that the advantages gained by inhibition of sickling have been offset by the rheological disadvantages of the higher haemoglobin level. The capillary bed in the perimacular region of the posterior pole has been used to examine the degree of vaso-occlusion in age and sex matched controls with SS disease with and without homozygous alpha thalassaemia 2. The results demonstrated significantly less capillary abnormalities in the perimacular region of patients with alpha thalassaemia, though the size of the foveal avascular zone and the grading of perimacular capillary drop-out did not differ between the 2 genotypes. These results are compatible with a mild inhibitory effect of alpha thalassaemia on vaso-occlusion of the macular vasculature in SS disease.

The physical effects of visco elastic substances on human donor cornea.

A case of corneal graft operation using chondroitin sulphate (CDS-TM) to protect the endothelium, highlights the surgical difficulties encountered as a result of the severe dehydration effects on the donor corneal button produced by the CDS. In vitro experiments comparing Healonid and CDS on 8 mm excised donor corneal buttons from three pairs of human eyes, confirms this effect with CDS which was absent with Healonid.

Central retinal artery occlusion without retrobulbar hemorrhage after retrobulbar anesthesia.

Four patients had central retinal artery occlusions after retrobulbar anesthesia with lidocaine HCl was administered before photocoagulation. One of these four had two separate episodes of closure. Only one had permanent visual loss, and none had evidence of retrobulbar hemorrhage. Each patient had a severe hematologic or vascular disorder. We think that direct trauma to the central retinal artery behind the globe, the pharmacologic or compressive effects of the injected solution, or both caused the occlusions in these patients.

Haematological factors associated with proliferative retinopathy in sickle cell-haemoglobin C disease.

In a selected sample of patients with sickle cell-haemoglobin C (SC) disease, proliferative retinopathy (PSR) occurred in 90/243 (37%) patients, developed most frequently between the ages of 20 and 30 years, and affected 68% patients aged 45 years or over. Comparison of haematological indices in patients with and without PSR, after age-related effects were allowed for, indicated significant relationships with high mean cell volume in males and with low fetal haemoglobin in both sexes. A highly significant relationship with total haemoglobin level in males (as previously reported in SS disease) was shown in SC disease to be entirely secondary to a strong age-related trend in haemoglobin level.

Angioid streaks in Jamaican patients with homozygous sickle cell disease.

Angioid streaks were observed in 21 of 242 patients with homozygous sickle cell disease. Two morphological types were observed. There is no evidence that angioid streaks in Jamaican patients are related to pseudoxanthoma elasticum.

Choroidal neovascularisation induced by photocoagulation in sickle cell disease.

Choroidal neovascularisation occurred in 35 out of 57 (61%) patients during a trial of xenon are photocoagulation in proliferative sickle retinopathy. Nineteen patients manifested abnormal vessel systems in the plane of the retina which tended to be benign, not enlarging, and without complications (choroidoretinal neovascularisation). In 16 patients the abnormal vessel systems grew into the vitreous, tended to increase in size, and to be associated with vitreous haemorrhage and retinal traction (choroidovitreal neovascularisation). Both forms of neovascularisation were significantly more common at younger ages. Treatment was generally unsatisfactory, frequently resulting in further enlargement of the lesions. Although the natural history of choroidal neovascularisation and its ultimate effect on visual function remains to be recorded, these lesions constitute a common and potentially serious complication of xenon are photocoagulation in proliferative sickle retinopathy as currently performed.