Laser in situ keratomileusis (LASIK) in myopia: 2-year results

Background: Long-term results on LASIK are not available to date. We therefore evaluated the predictability, stability and complication rate after LASIK in moderate – to-high myopia. Patients and methods: We treated 70 eyes (41 patients) using the Automatic Corneal Shaper and the Keracor 116 excimer laser. Patients were followed for 1, 6, 12 and 24 months. Spectacle refraction, visual acuity, rate of retreatment, and patient satisfaction were evaluated. Results: At 24 months the results were as follows: Myopia −5 to −9.9 D (n =18): 94 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 6 % (6 %); uncorrected acuity 20/40 or better in 83 %; no loss of 2 ore more lines of visual acuity; 89 % highly satisfied. Myopia −10 to −14.9 D (n = 12): 88 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 20 % (0 %) ; uncorrected acuity 20/40 or better in 72 %; 4 % lost 2 or more lines of visual acuity; 96 % highly satisfied. Myopia −15 to −29 D (n = 22): 33 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 41 % (18 %); uncorrected acuity 20/40 or better in 7 %; no loss of 2 or more lines of visual acuity; 67 % highly satisfied. Conclusion: LASIK is an accurate, effective and stable procedure for correcting myopia of −5 to −10 D. Results are less precise in myopia up to −15 D, and some visual loss occurs in a number of patients. In myopia > −15 D, results are not satisfactory because of poor accuracy and low stability.      

Intraoperative and postoperative complications after laser in situ keratomileusis (LASIK)

Purpose: To quantify the incidence and type of complications after LASIK for the correction of myopia with special consideration to the time lapse after surgery and the possible consequences regarding high-contrast sensitivity and other modalities of visual acuity. Material and methods: Between January 1995 and April 1997, 125 eyes of 88 patients with myopia greater than −6.0 D who could not wear contact lenses were operated on at our institute. In this prospective study the patients were examined consecutively preoperatively as well as postoperatively at day 4 and months 1, 3 and 6. The complications were divided into three groups (intraoperative, early postoperative and late postoperative). Results: Our complication rate was 7.2 % (loss of 2 lines of visual acuity) – with cutting artifacts related to the microkeratome, wrinkling of the flap and epthelial ingrowth. Conclusions: LASIK is a microsurgical procedure that requires adequate experience and the desire by the surgeon for self-evaluation. In spite of the good clinical results in the correction of high myopia the complication rates seems still to be too high. This should be the objective for further improvement primarily related to the microkeratomes.      

Mesopic vision after LASIK for myopia

Fragestellung: Bisher liegen keine Erfahrungen über das D?mmerungssehverm?gen nach LASIK vor. Wir untersuchten daher das D?mmerungssehen vor und nach LASIK zur Korrektur der Myopie. Patienten und Methode: 34 Patienten (67 Augen), die mit dem Automatic Corneal Shaper und dem Keracor 117CT Excimer Laser operiert wurden und pr?operativ einen korrigierten Visus von 0,8 erreichten. Wir untersuchten pr?operativ und 1 Jahr postoperativ die Refraktion, den Visus und das D?mmerungssehverm?gen ohne und mit Blendung (Nyktometer, Fa. Rodenstock) in Abh?ngigkeit von der Ausgangsrefraktion in drei Gruppen und verglichen den Anteil der Patienten, die einen Kontrast von 1 : 5 oder geringer erkannten. Ergebnisse: Myopie −1 bis −5 dpt (Gruppe 1; n = 26): Pr?operativ (postoperativ) erkannten ohne Blendung 89 % (96 %) (nur hier signifikanter Unterschied; p = 0,03) und mit Blendung 65 % (73 %) die Kontraststufe 1 : 5. Myopie −5,1 bis −10 dpt (Gruppe 2; n = 24): Pr?operativ (postoperativ) erkannten ohne Blendung 83 % (75 %) und mit Blendung 50 % (21 %) die Kontraststufe 1 : 5. Myopie −10,1 bis −15 dpt (Gruppe 3; n = 11): Pr?operativ (postoperativ) erkannten ohne Blendung 73 % (55 %) und mit Blendung 46 % (27 %) die Kontraststufe 1 : 5. Schlu?folgerung: Nach LASIK scheint es für Korrekturen von mehr als −5 Dioptrien zu einer Verschlechterung des D?mmerungssehverm?gens unter Blendung zu kommen. Bei Korrekturen ab −10 dpt verschlechtert sich auch das D?mmerungssehen ohne Blendung. Allerdings waren die Unterschiede nicht statistisch signifikant. Zudem ist das D?mmerungssehen bereits pr?operativ bei h?herer Myopie erheblich reduziert.      

Correction of myopia and astigmatism using laser in situ keratomileusis

Patients and methods: In order to better define the potential advantages and risks of laser in situ keratomileusis (LASIK), we designed a prospective study including 73 eyes. Results: After 6 months, 62 eyes were examined. Myopia was corrected from –6.10 ± 3.12 (mean ± standard deviation) to + 0.04 ± 0.66 D, with 54 eyes (87.1 %) being within ± 1.00 D of emmetropia. Astigmatism was corrected from –1.07 ± 1.02 to –0.32 ± 0.89 D. Uncorrected visual acuity was 0.5 or better in 59 eyes (95.2 %) and 1.0 or better in 27 eyes (43.5 %) 6 months postoperatively. More than one line in best-corrected visual acuity was lost by 6 eyes (9.7 %), with most of these eyes being highly myopic. There was no change or a gain in lines in best corrected visual acuity in 42 eyes (66.1 %). Intraoperative complications arose in two eyes (2.7 %); in one eye, visual acuity was temporarily decreased. More treatments were performed in 7 eyes (9.6 %). Postoperatively, no haze, scars or central islands were detected. Patient satisfaction after LASIK was high: 97.3 % were pleased or very pleased with the result. Conclusions: In conclusion, LASIK is effective in the correction of myopia and myopic astigmatism. Although complications more frequently occurred in the correction of higher refractive errors, LASIK seems to be relatively safe compared with other refractive methods.      

Results of implantation of transsclerally sutured posterior chamber lenses in combination with penetrating keratoplasty

Summary Implantation of transsclerally sutured posterior chamber lenses is one possibility of surgical visual rehabilitation of eyes with pseudophacic or aphacic bullous keratopathy without zonular-capsular support. We analyzed the results and complications of the surgical procedures performed in our institution. Patients and methods: Out of 1567 penetrating keratoplasties and 220 transsclerally sutured posterior chamber lenses that were performed at our institution between 1991 and 1996, patients that underwent penetrating keratoplasty and sutured posterior chamber lens implantation in whom sufficient clinical information was available were selected and analyzed in a retrospective, nonselective study. Surgery was performed by a total of four surgeons and included anterior vitrectomy, inside-out suturing and synechiolysis if necessary. Detailed pre- and intraoperative data, postoperative course and complications were recorded and analyzed. Results: A total of 96 eyes were analyzed (patient age 17–92 years, 49 male, 46 female). Penetrating keratoplasty was performed for pseudophacic (63) oder aphacic (15) bullous keratopathy or for corneal scars following penetrating injury (18). Mean follow-up was 22 months. In 82 of 96 eyes, visual acuity improved following surgery. Complications included rhegmatogenous retinal detachment in 4 eyes, graft rejection in 5 eyes, secondary angle-closure glaucoma caused by preexisting anterior synechiae in 7 eyes, and persisting cystoid macular edema in 19 eyes. Luxation or subluxation of the IOL and endophthalmitis were not observed in any of the patients. Conclusion: Implantation of transsclerally sutured posterior chamber lenses appears to be a safe procedure and is considered by us to be the procedure of choice to correct aphacia during penetrating keratoplasty in eyes with absent zonular-capsular support. The majority of postoperative complications is apparently caused by preexisting problems related to previous surgery and/or trauma, such as peripheral anterior synechiae, vitreous incarceration or cystoid macular edema.      

Diode laser thermokeratoplasty – first clinical experience

Purpose: Pulsed holmium lasers are currently used to correct hyperopia by means of laser thermokeratoplasty (LTK). Series of μs laser pulses are applied with a high repetition rate to induce shrinkage of corneal collagen fibers. The pulsed energy application results in intrastromal temperature peaks of up to 200 °C. A continuously emitting laser diode can – as we demonstrated recently in an invivo study on minipigs – be used for LTK and may be of advantage because the temperature rise is more steady. The aim of this study was to examine the safety, amount, and stability of hyperopic correction of diode LTK on blind human eyes. Methods: We used a laserdiode that was set to continuously emit light at λ = 1.854 μm/μ_a = 1.04 mm^–1(group I, n = 4) or 1.87 μm/μ_a = 1.92 mm^–1 (group II, n = 4). Radiation energy was 100 to 150 mW for 10 s per coagulation. Eight coagulations on a single ring (group I) and 16 coagulations on a double ring (group II) diameter were applied in the cornea concentric to the entrance pupil by means of a vacuum-fixed application mask (group I = conjunctival fixation; group II = corneal fixation) and a handpiece with a focusing optic. Preoperatively as well as 1 week, 1, 2, 3, 6 12 and 18 months postoperative ophthalmologic controls were performed and the corneal refractive power was measured. Results: In group I initial refractive changes of up to + 4.9 D were achieved (1 week postoperative). However, due to the great penetration depth of the laser irradiation, large endothelial defects resulted beneath the stromal coagulations. In group II an initial refractive change of up to + 6.8 D was achieved and as a result of the reduced penetration depth, the endothelial cell damage was much reduced. Partial regression of the refractive effect occured in all subjects, which continued in higher refractive changes during the 2^nd postoperative year. The refractive effect at 12 months was + 0.6 to + 1.5 D in group I and + 0.9 to + 5.7 D in group II. At 12 months the induced astigmatism was 0.5 to 2.2 D in group I and 0.3 to 1.6 D in group II. No serious adverse effects were noticed. Conclusion: A continously emitting laser diode working at a wavelength of 1.87 μm can be used to correct hyperopia by means of LTK safely and effectively. Regression occurs predominantly in the first 6 postoperative months. Further studies must be conducted to determine the importance of patient inherent parameters such as age in establishing a nomogram.      

Contact lens intolerance in infantile aphakia – indication for intraocular lenses?

Summary Due to the low rate of complications, lentectomy and contact lens fitting is the standard treatment for congenital cataract. However, contact lens fitting is not possible in all children. The authors report the main reasons for discontinuation of contact lenses in their patients. Method: In 134 consecutive lentectomies of 90 children, the underlying eye diseases and general diseases, the age at operation, compliance of parents and children, and social background were analyzed. Results: Twenty of the 90 children had to discontinue contact lens wearing. Twelve of these children were operated on one eye and 8 on both eyes. Only 2 children showed signs of contact lens complications. In 2 children treatment was stopped because of the poor visual prognosis and in 10 children the parents discontinued contact lens treatment because of a severe handicap of the child (n = 2) or due to misunderstanding and parental noncompliance (n = 8). Six children refused contact lenses without obvious reasons. Among the latter, children 2–4 years of age were at the greatest risk. Children with additional systemic abnormalities frequently developed contact lens intolerance. Conclusion: In children with systemic abnormalities and in the case of parental communication and compliance problems, discontinuation of contact lenses has to be expected in up to 30 % of cases. In these children and in children who object to contact lenses at the age of 2–4 years, intraocular lens implantation should be considered, especially in unilateral cataract, if successful contact lens treatment is not achievable within 8–12 weeks.      

Bilateral cystoid macular edema following successful treatment of AIDS-associated CMV retinitis

Background: Cystoid macular edema (CME) in AIDS patients with inactive cytomegalovirus (CMV) retinitis is an uncommon but potentially sight-threatening complication. The pathogenesis of CME in these patients is unclear. This study tries to identify possible risk factors by analyzing the charts of five patients. Methods: Ten eyes of 5 patients that finally developed CME were followed for an average of 18 months. The initial retinal lesions, their response to antiviral treatment, the development of CME, and the patients' immune status were prospectively monitored. Results: CMV retinitis was diagnosed at a median CD4+ count of 3 cells/mm³ (range 0–11). All eyes responded to the initial systemic anti-viral treatment. At the onset of CME, CMV retinitis was controlled by antiviral maintenance therapy in all patients [ganciclovir (n = 2), cidofovir (n = 2), foscarnet (n = 1)]. The median time between diagnosis of CMV retinitis and onset of CME was 11.5 months (range 5–24). Development of CME was associated with significant visual loss: acuity ranged from 0.05 to 0.7 when CME was first noticed, compared to 0.8–1.25 at diagnosis of CMV retinitis. Duration of inflammation, size or zone of retinal necrosis did not favor the development of CME, neither did the antiviral therapy. A weak correlation of CME development and immune status (expressed as increase of CD4+ cells) was found. Due to systemic corticosteroids CME resolved. Conclusions: CME is a new visual threat to AIDS-patients with CMV retinitis whose immune status improved under the latest combined antiretroviral therapy. Therapy with oral corticosteroids may positively influence this condition.      

Phototherapeutic keratoectomy (PTK) after keratoconjunctivitis epidemica

Background: Persistent and recurrent nummuli after epidemic keratokonjunktivitis (EKC) often lead to reduced visual acuity and increased glare. In spite of long-term topical steroid therapy nummuli often recur. We tried to treat persistent nummuli with phototherapeutic keratectomy (PTK). Patients: PTK with an excimer laser (193 nm) was performed in 13 eyes of 9 patients with nummuli. The nummuli were observed over 3–72 months (mean: 36 months). Preoperatively, the visual acuity was 0.1–0.9 (mean: 0.39 ± 0.22) and the brightness acuity test (BAT) was 0.05–0.5 (mean: 0.25 ± 0.15). Prior to PTK all eyes had been treated with local steroids several times for recurrent nummuli. Results: During the follow-up from 15 to 56 months (mean: 33 ± 11.5 ms), 11 eyes had an increase in visual acuity: 0.3–1.0 (mean: 0.63 ± 0.26). The reduction of glare was especially beneficial for the patients: 0.3–0,9 (mean: 0.55 ± 0.21). One patient had a recurrence of nummuli in both eyes 6 weeks after PTK. The subjective-induced spheric refractive change was − 2.5 D to + 2.0 D. The astigmatic error changed between − 2.0 D to + 1.5 D. Conclusion: PTK seems to be an effective method of treating persistent, recurrent nummuli after EKC. The low rate of recurrence of nummuli after PTK is remarkable.      

Influence of postoperative topical application of miotics after cataract extraction on intraocular pressure and the blood-aqueous barrier

Background: In the present study we evaluated the influence of topical miotics on intraocular pressure and the blood-aqueous barrier after uncomplicated phacoemulsification and PC-IOL implantation. Patients and methods: Fifty-two eyes were randomized into 2 groups: with miotics (n = 28) and without miotics (n = 24). The IOP was measured before, 6 h, 1 and 2 days after surgery. Measurement of aqueous flare was performed before and on days 1 and 2 after surgery. Patients with glaucoma, PEX or previous intraocular surgery were excluded. Results: In the group without miotics the IOP was 17.9 mm Hg (± 3.34) 6 h postoperatively; in the second group it was 15.5 mm Hg (± 3.25); P = 0.04. On the first postoperative day the IOP measured in the group without miotics was 15.3 mm Hg (± 2.70) and with miotics 13.0 mm Hg (± 2.28); P = 0.007. On the second day in the group without miotics the IOP was 13.9 mm Hg (± 3.05) and with miotics 12.60 mm Hg (± 2.19); P = 0.53. The changes in aqueous flare on the first and second day after surgery showed no significant influence of miotics on the blood-aqueous barrier (P > 0.05). Conclusions: Immediate postoperative application of topical miotics led to a small yet significant reduction of the IOP during the first 24 h after surgery. Our data suggest that there is no need for pharmacological reduction of the IOP after uncomplicated cataract surgery.      

Radiotherapy for choroidal neovascularization in age-related macular degeneration. A pilot study using low- versus high-dose photon beam radiation

Purpose: Several pilot studies have indicated that low-dose radiation therapy might have a beneficial effect on the course of choroidal neovascularization (CNV) in age-related macular degeneration (AMD). This study aimed to ascertain whether such treatment might halt the progression of neovascular AMD and whether a low or a high radiation dose should be applied. Patients: The patients comprised some randomized to 0 vs 10 vs 36 Gy of radiation and (after a change of the study protocol became necessary) others who participated in a prospective, controlled non-randomized pilot study. Enclosed were eyes with visual acuity of ≥ 0.1 and ≤ 0.6 revealing a juxta-subfoveal CNV either of the occult type (type 1) or the classic type (isolated or as part of a predominantly occult lesion). Results: Eyes treated with 10 Gy for occult CNV (n = 12) were subject to severe visual loss in 41.6 % of the cases compared to 38.5 % in the control group (n = 13) at 12 months of follow-up. For eyes treated with 10 Gy because of classic CNV, the corresponding figures were 33 % (n = 18) and 57 % (n = 14) respectively. At 18 months of follow-up, the percentages were 63 % and 75 % respectively. Fluorescein angiographic growth of classic and occult CNV could not be halted by 10 Gy, while a temporary growth retardation was observed in cases irradiated with 36 Gy. Conclusion: In the study presented, the natural course of occult CNV could not be improved by irradiation with 10 or 36 Gy. In cases of classic CNV, low-dose irradiation with 10 Gy postponed severe visual loss by a maximum of 18 months. A positive treatment effect was also observed in cases irradiated with 36 Gy; however, a 25 % incidence of radiation retinopathy seems unacceptable.      

The effects of changed biomechanical parameters on measurements of intraocular pressure in keratoconus patients

Background: Keratoconus is associated with changes in the corneal structure, such as defects of Bowman's layer, a decrease of corneal thickness etc. They result in alterations of some of the biomechanical parameters of the cornea, namely, rigidity and elasticity. The present study was performed to examine how impression tonometry and applanation tonometry for determination of intraocular pressure (IOP) are affected by the changed biomechanical parameters associated with keratoconus. Patients and methods: We examined 20 normal subjects (40 eyes) and 17 keratoconus patients (25 eyes). The corneal thickness was measured by ultrasound pachymetry in the corneal center. In the keratoconus patients, an additional measurement was made at the conus peak. The corneal curvature was determined using the TMS keratoscope. The IOP measurements were made with the Schi?tz tonometer (10 g). For comparison, additional IOP measurements in the corneal center and, in the keratoconus group, on the conus peak were made with the applanation tonometer. Results: The normal subjects had a central corneal thickness of 548 ± 30 μm, compared to 505 ± 42 μm in the corneal center and 425 ± 41 μm on the conus peak in keratoconus patients. The average corneal curvature was 43.3 ± 1.8 D in the normal subjects and 47.8 ± 4.1 D in keratoconus patients. Applanation tonometry produced results on 11.33 ± 1.43 mm Hg in the normal group (corneal center) compared to values of 12.00 ± 2.55 mm Hg (corneal center) and 7.30 ± 1.95 mm Hg (conus peak) in the keratoconus cohort. The coefficient of rigidity was 0.0236 ± 0.0026 μl⁻¹ in the normal subjects, compared to 0.0173 ± 0.0050 μl⁻¹ in the keratoconus patients. Conclusion: The morphological changes associated with keratoconus may cause tonometry errors.      

Comparative laser flare measurement and fluorophotometry in anterior and posterior uveitis

Summary Recent studies have sought to quantify aqueous flare by laser flare measurement. An increase in aqueous flare caused by a rise of protein concentration was frequently found both in anterior and posterior segment disease. This has been interpreted as a breakdown of the blood – aqueous barrier (BAB). By measuring the diffusion coefficient of the BAB compared to the aqueous flare value in patients with anterior and posterior uveitis, the extent to which the increase in flare value was related to a possible break down of the BAB was examined. Patients: Thirty-nine normal eyes (23–78 years; 41.6 ± 18.6), 18 eyes with anterior uveitis (iritis, iridocyclitis; 18–57 years; 35.2 ± 12.4) and 29 eyes with posterior uveitis (chorioretinitis or retinochorioiditis; 18–51 years; 31.7 ± 10.5). The diffusion coefficient P(a) of the BAB was measured fluorophotometrically, while the flare value was quantified by laser flare measurement. Results: Flare values (1/ms) were found to be significantly increased (p < 0.001) compared to normal eyes (4.6 ± 1.7) both in anterior uveitis (20.9 ± 8.5) and in posterior uveitis (17.4 ± 8.3) but did not significantly differ between them (p = 0.43). The diffusion coefficient P(a) (10^–3/min) of the BAB was not significantly different (p > 0.05) between normal eyes (0.5 ± 0.2) and eyes with posterior uveitis (0.9 ± 0.7), whereas it was significantly increased (p < 0.001) in anterior uveitis (6.5 ± 5.4) compared to the other groups. Conclusions: (1) In posterior uveitis, an increased flare value is not necessarily correlated with a breakdown of the BAB; proteins may enter the aqueous from posterior. (2) Assessing the function of the BAB in posterior segment disease using laser measurement should be carried out with caution; if possible, permeability measurements of the BAB should be undertaken seperately.      

Pseudophakia in children with juvenile arthritis

Background: Cataract secondary to juvenile rheumatoid arthritis is a severe, vision-threatening complication in early childhood. Intraocular lens implantation is controversial. The follow-up of four pseudophakic eyes of three patients and their perioperative therapeutic regimen were retrospectively analyzed. Early and late postoperative complications are reported. Patients and methods: Both girls had lens aspiration and posterior lens implantation at the ages of 6 and 12 years, the boy at the age of 10 and 14 years. All patients had relapsing anterior uveitis. The follow-up time was 3 years (1–6 years). One girl was diagnosed with sarcoidosis, causing juvenile arthritis. Both girls had perioperative methothrexate and prednisolone therapy. The boy had azathioprine therapy at the time of his first cataract surgery; later he had no systemic therapy. Both girls' intraocular lenses were implanted at different eye hospitals. Results: Both girls had severe inflammatory reactions after surgery. At the hospitals both eyes had surgical revision for iris capture. In one case this was combined with exchanging the intraocular lens. Iris capture persisted for this eye and later vitrectomy with silicone oil filling was necessary to delay phthisis, resulting in amaurosis. For two pseudophakic eyes vitrectomy was necessary later because of severe vitreous opacities, but visual acuity was severely diminished by chronic cystoid macular edema and epiretinal membranes. The boy developed in his second eye intermittent iris bombata and persistent secondary glaucoma, visual acuity was stabilized at 0.5. Conclusions: Secondary cataract due to juvenile rheumatoid arthritis or sarcoidosis is a difficult situation for phacoemulsification with intraocular lens implantation in children. For severe inflammatory complications intense local and systemic anti-inflammatory therapy is mandatory. Visual prognosis is reduced for the uveitic posterior segment and glaucoma complications. IOL implantation can be recommended for only a very few patients.      

Postoperative failure rates with external DCR – an indication for surgical repair of canalicular occlusion

Summary Failures with external DCR have also been attributed to canalicular occlusion. Since 1976 we have documented all patients with surgical reconstruction of occluded canaliculi. The indication, different surgical methods of choice and functional prognosis were evaluated. Patients and methods: From 1976 to 1997 we have treated 272 cases. The surgical technique canaliculodacryocystorhinostomy (n = 132) was performed in 45 %. Thirty operations (11 %) of occluded lacrimal canaliculi due to external DCR were done. The patients ranged in age from 2 to 79 years. We examined all 29 patients (10 male, 19 female) with 30 operations (1 patient was operated on in both eyes). Results: The surgical procedure was performed after an interval of 1 month to 24 years (average 4 years). Seven times a second external DCR was done. Special causes of canalicular obstruction were severe previous soft tissue and bone trauma (4 patients) and congenital defects (3 patients). Canaliculorhinostomy was performed 15 times, canaliculodacryocystorhinostomy 14 times and conjunctivorhinostomy once. Fifteen operations had good functional results (without any symptoms). Five patients had good irrigation, but a prolonged fluorescein dye disappearance test. There were 10 failures with complete closure of the canaliculi. Conclusion: If failure with external DCR is caused by canalicular occlusion, the microsurgical technique has a possible success rate for long-term results of about 50 %. Before hand, however, all prophylactic measures have to be taken to avoid this postoperative failure.      

Assessment of refractive change following photorefractive keratectomy: keratometry versus computerized videokeratography

Summary The purpose of this study was to determine which corneal curvature values most closely correlated to change in subjective manifest refraction following excimer laser photorefractive keratectomy (PRK). Methods: Excimer laser PRK was performed on ten eyes of ten patients (mean age: 37.3 years). Preoperative refractive errors ranged from –2.25 to –8.75 diopters. Preoperatively and 1 month postoperatively, we determined the spherical equivalent of the manifest refraction (corrected for a 12 mm vertex distance) and measured corneal power using standard keratometry (Bausch and Lomb keratometer) and computerized videokeratography (EyeSys Corneal Analysis System). We collected five corneal values: standard keratometry, videokeratography-derived simulated keratometric readings calculated using the axial, instantaneous and refractive formulas, and corneal refractive power over the central 3-mm zone (effective refractive power); apart from the traditional refractive index of the cornea (n = 1.3375), we used the refractive value of the anterior corneal stroma (n = 1.376). For each of the five corneal values, we subtracted the change in corneal power from the change in manifest refraction and calculated the means and standard deviations. Results: The mean differences between the refraction and the corneal values for a refractive index of 1.3375/1.376 were: 0.89 ± 0.54^*/1.26 ± 0.59* for standard keratometry; 1.64 ± 0.75^*/1.37 ± 0.7*, 4.03 ± 1.86^*/3.86 ± 1.87*, and 1.16 ± 0.76^*/0.91 ± 0.74* for the axial, instantaneous, and refractive videokeratography values, respectively; and 0.83 ± 1.03^*/0.39 ± 1.08 for the effective refractive power (*, p < 0.05). Conclusions: In our series, only the values for the effective refractive power, calculated with the refractive index of the anterior stroma of the cornea, were not statistically different from the change in manifest refraction.      

Correction of myopic astigmatism by combined treatment with PRK and T-incision and photoastigmatic refractive keratectomy

Background: In contrast to the correction of simple myopia there is no widely accepted technique for the correction of myopic astigmatism. Currently two techniques are available: the photoastigmatic refractive keratectomy (PARK) and the combination of arcuate keratotomies with standard PRK (PRK-T). Methods: In two groups, 67 patients underwent a correction of myopic astigmatism in a total of 87 eyes (19 by PRK-T and 68 by PARK), and were followed for 1 year. The spherical equivalent was − 6.7 D in both groups and the refractive astigmatism ranged from − 1.0 to − 6.5 D. The PARK procedure was performed by means of an elliptic ablation (Kertom I, Schwind) with a 5.8 × 8.1 mm zone. The PRK-T technique consisted of two arcuate keratotomies with a free optical zone of 7 mm and a standard myopic PRK at least 6 weeks later. Results: The 1 year follow-up was completed in 57 out of 87 eyes included in the study. At 1 year post-operation, 83 % of the PRK-T group and 80 % of the PARK group had an uncorrected visual acuity of 20/40 or better. The refractive astigmatism was reduced by 76 % in the PRK-T group and by 67 % in the PARK group. The spherical equivalent was − 0.59 ± 1.1 D at 1 year after PRK-T and − 0.28 ± 1.04 D after PARK. In three eyes of the PARK group (6.7 %) a visual loss of more than one Snellen line occured. Two of these eyes had a preoperative myopia of more than − 6 diopters. Conclusion: Both techniques have the potential to reduce myopic astigmatism, however, the success rate is not as high compared to spherical PRK. Also, the complication rate of 2.5 % in corrections to − 6 D is significantly higher than that with spherical myopic PRK.      

Cataract surgery at the Virchow Clinic in Berlin. Review of the last 16 years

Purpose: The aim was to compare the different techniques of cataract surgery regarding early postoperative astigmatism and visual acuity. Patients and methods: The data of three groups of patients (100 eyes) were analyzed retrospectively (1980–1982; 1987–1990; 1991–1993). Three different techniques of cataract surgery were used. Included in the prospective study were the data for 285 eyes, which underwent phacoemulsification, self-sealing incision and controlled induction of astigmatism. Results: In the time period retrospectively investigated, we found that because of the advancements in operation methods, there was a reduction in the amount of surgically induced astigmatism. From 1980 to 1995 there was a clear increase in the number of patients with early low-grade postoperative astigmatism < 1 D (1980–1982: 6 %, 1987–1990: 19 %, 1991–1993: 64 %, 1994–1995: 84 %). There was an improvement in postoperative vision (with correction > 0.5) of 16 % in 1980–1982 to 45 % from 1987 to 1990, 58 % from 1991 to 1993, and to 76 % in 1994–1995. Conclusions: Surgically induced astigmatism, which was considered to be a sign of unwanted increased postoperative astigmatism, was reduced from 1980 to 1993. Through controlled induction of astigmatism it was possible to compensate for preoperative astigmatism in the prospective group. Improved surgical techniques led to improvements in early postoperative visual acuity.      

Intravitreal injection of cidofovir in CMV retinitis

Background: CMV retinitis is the most common opportunistic ocular infection and the main cause of blindness in AIDS patients with a T-helper cell count ≤ 50/μl. Cidofovir is a nucleotide analogue with a long half-life time after phosphorylation intracellularly. It is effective against CMV and can be given intravenously and intravitreally. The aim was to offer an alternative therapy for CMV retinitis to patients who could not receive standard treatment because of contraindications or refused it. The efficacy and tolerance of intravitreal injections of cidofovir should be evaluated. Patients and methods: We treated 16 eyes of 12 patients. The total number of injections with 15 μg of cidofovir each was 49, with an average of 3 injections per eye. The duration of follow-up was 75–295 days (median 170 days). Probenecid was given concomitantly. Injections were repeated after 6–10 weeks. Secondary prophylaxis of CMV organ infection was done with oral ganciclovir. Results: Within a few days all areas with active retinitis turned into scars following the first injection. Under consequent treatment no reactivation was observed. Four eyes developed a mild iritis with hypotony within a mean time of 12 days after injection. All responded rapidly to topical steroids. None had a persisting loss of vision. Two eyes developed cystoid macular edema (CME). Two patients stopped anti-CMV treatment (ganciclovir orally and injections), followed by a recurrence after an average of 64 days. Conclusions: Intravitreal injection therapy with 15 μg cidofovir and concomitant oral probenecid is a valuable and safe alternative treatment for CMV retinitis in AIDS patients. Its main complication is iritis with hypotony, which is effectively treatable with topical steroids. No complications caused by the injection technique itself were noted. The occasional observation of CME in otherwise quiet eyes, however, is probably drug-related.      

A prospective study investigating the long-term stability of changes in astigmatism following arcuate lamellar keratotomy (ALK): 3-year results

Introduction: The correction of low to moderate astigmatism is possible today by means of photoablation (PRK), while the treatment of moderate and higher astigmatism still involves refractive keratotomy. Experience has shown that cataract surgery, using modern tunnel techniques with self-healing incisions, results in earlier stability in both the refractive outcome and wound healing. In this study, we attempted to combine the advantages of lamellar keratotomy with those of a pair-wise T-incision as arcuate lamellar keratotomy (ALK). Patients and methods: The clinical outcome of 41 patients who underwent ALK was investigate in a prospective study over a period of 3 years. The pre- and postoperative investigations undertaken included the measurement of astigmatism using a Zeiss keratometer, uncorrected visual acuity, and corrected glare vision using a Humphrey autorefractor. All patients had astigmatism between 2.0 and 7.0 D. Together with a uniform arcuate incision, we used 7 mm (n = 26) and 8 mm (n = 15) mm zones for correction. Results: The average preoperative astigmatism was 4.01 ± 1.90 (median, 3.50) D. After a 3-year follow-up the average postoperative astigmatism was 1.59 ± 1.29 (median, 1.38) D. The astigmatic change induced (Jaffé) after 3 years was about 3.23 ± 2.23 (median, 3.16) D. The average uncorrected visual acuity (log MAR) before ALK was 0.20 ± 0.12 (median, 0.22) and after follow-up, 0.41 ± 0.14 (median, 0.39). Corrected glare vision before surgery was 0.23 ± 0.19 (median, 0.10) and afterwards, 0.25 ± 0.22 (median, 0.14). Conclusions: Arcuate lamellar keratomy (ALK) stood the test as a routine clinical procedure for correction of moderate astigmatism with stable postoperative functional outcomes. We did not find impairment of glare vision following this procedure.