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PubMed1981

A clinical investigation of the surgical correction of myopia by the method of Fyodorov.

The surgical correction of myopia using the method of Fyodorov known as radial keratotomy consists of 16 partial thickness, radial incisions in the cornea, which result in central flattening and peripheral bulging, reducing the degree of myopia. The purpose of this investigation was to determine: (1) the amount of myopia correctable; (2) the time required for stabilization of corneal curvature changes; (3) the degree to which the variables affect the results; (4) the surgical and postoperative complications; and (5) patient motivation and satisfaction. Preliminary results revealed a significant reduction of the myopia. The keratometry readings and refractive correction required appeared to stabilize by the third month. Fluctuating vision and increased glare were the most frequent complications encountered. The preliminary results of 20 cases followed for six months postradial keratotomy are reported.

Adolescent↗
PubMed1986

Myopia associated with retinopathy of prematurity.

A complete analysis of the components of refractive error was performed on ten eyes of five patients with myopia and retinopathy of prematurity (ROP). In comparison to an age-matched control group, these eyes exhibited both lenticular and axial myopia. Only the high crystalline lens powers, which ranged from 22.20 to 44.13 diopters (D) (mean value, 31.27 D), were found to be statistically significant. In two patients, only one eye had high myopia. The lens power in these eyes was approximately 11 D more powerful than the lens of the fellow eye. Further investigation into the ocular changes induced by prematurity and abnormal oxygen metabolism is needed to determine the reason for the high degree of lenticular myopia.

Child↗
PubMed1994

193-nm excimer photorefractive keratectomy in high myopia.

PURPOSE: To evaluate the refractive results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on 48 highly myopic eyes in a multicenter study. METHODS: A Visx 2015 or 2000 argon-fluoride excimer laser and a single-zone ablation technique were used. Postoperatively, eyes were treated with topical fluoromethalone for up to 5 months. Most eyes were treated with a 6.0- to 6.2-mm beam diameter after undercorrections and increased regression were noted with a 5.5-mm beam in earlier studies. Forty-eight eyes were treated for myopia, which was between -8.0 and -15.25 diopters (D) (spherical equivalent). The mean preoperative refraction was -11.2 D. Retreatment was performed after 6 to 16 months on 11 eyes for undercorrection. All eyes not retreated were followed for at least 12 months. RESULTS: At 6 months, follow-up was available on 47 eyes. Of these eyes, 40% and 64% achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 60% of eyes attained 20/40 visual acuity or better uncorrected. Eleven patients (23%) were retreated between 6 to 16 months for undercorrection and/or regression. After retreatment, 47% and 81% of eyes achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 15% of eyes lost two lines of best-corrected visual acuity, and no eyes lost more than two lines. There was slightly more corneal haze seen in this group compared with the haze seen in patients undergoing PRK for low and moderate myopia. CONCLUSIONS: These data show that excimer PRK can correct high amounts of myopia with reasonable stability after 6 months. Excimer PRK is an effective surgical treatment of severe myopia, but long-term follow-up is still needed to assess the stability of its effect.

Adult↗
PubMed1998

Retreatment after photorefractive keratectomy for low myopia.

OBJECTIVE: The purpose of the study was to evaluate the results of retreatment for low myopia after primary photorefractive keratectomy (PRK). DESIGN: A prospective study. PARTICIPANTS: A total of 48 eyes of 37 patients from 566 eyes of 331 patients originally treated for myopia of up to -6 diopters (D) were studied. INTERVENTION: Photorefractive keratectomy by the Coherent Schwind Keratom II excimer laser was performed. MAIN OUTCOME MEASURES: The parameters evaluated were visual acuity, refraction, and corneal clarity. RESULTS: Of the 566 eyes with myopia up to -6 D, 48 eyes (8.5%) required retreatment. The sphere (mean +/- standard deviation) was -0.88 +/- 1.24 D before second surgery. At 6 months, the mean was -0.04 +/- 0.91; at 1 year, it was -0.33 +/- 0.75 D. At 6 months, 75% of sphere value was within +/- 1 D. The preoperative uncorrected visual acuity (UCVA) was 20/200 or worse in 12.8% of eyes and 20/40 or better in 40.4% of eyes. Six months after reoperation, 20/60 UCVA was obtained in 17.4% of eyes. All others (82.6%) had UCVA of 20/40 or better, 26.1% better than 20/20. The proportion of eyes with best spectacle-corrected visual acuity better than 20/20 decreased from 60.0% to 47.1% 6 months after reoperation. Six months after reoperation, haze 1 was present in 42.9% and haze 2 in 4.7% of eyes, and in no eye was haze worse. CONCLUSION: Retreatment after PRK for low myopia can significantly increase UCVA and decrease residual refractive error without significant complications.

Adult↗
PubMed1999

Complications of laser in situ keratomileusis for the correction of myopia.

OBJECTIVE: To determine the incidence and severity of complications from laser in situ keratomileusis (LASIK) for the correction of myopia by experienced and inexperienced surgeons. DESIGN: Prospective, observational clinical study. PARTICIPANTS: Fourteen surgeons and 1062 eyes of 574 myopic patients who desired surgical correction of myopia ranging from -2.00 to -22.50 diopters (D; mean, -7.57 D) and astigmatism no greater than 4.00 D participated in this study. INTERVENTION: Myopia was corrected with LASIK. Astigmatism was corrected with arcuate keratotomy at the same time as the initial procedure or subsequently. MAIN OUTCOME MEASURES: Primary outcome measures were change in best spectacle-corrected visual acuity (BSCVA) and the incidence of complications. RESULTS: Eyes were followed for a mean of 9.5 months after their last surgical procedure (range, 2 weeks-21 months). Three hundred eighty-one eyes (36%) underwent 468 enhancement procedures 3 months or more after the initial treatment. There were 27 (2.1%) intraoperative and 40 (3.1%) postoperative complications. Laser ablation was not performed during the initial treatment of 17 (1.6%) eyes because of intraoperative complications. Seventy-four eyes gained 2 or more lines of BSCVA, while 50 eyes lost 2 or more lines of BSCVA. Only three eyes lost two or more lines of BSCVA to a level worse than 20/40. One eye with a flap buttonhole (BSCVA 20/50) also had an epiretinal membrane. The second eye (BSCVA 20/60) had a flap buttonhole that may have been related to a previous corneal transplant. The third eye (-22.50 D before surgery) had a rhegmatogenous retinal detachment develop, reducing BSCVA from 20/60 to 20/200. The incidence of intraoperative complications decreased from 3.1% during the first 3 months to 0.7% during the last 9 months of the study (P = 0.02). CONCLUSIONS: LASIK is acceptably safe for the correction of myopia. Although complications occur in approximately 5% of cases, these rarely lead to visual loss of more than two Snellen lines and postoperative acuity below 20/40. Flap buttonholes were more likely to cause loss of BSCVA than free or incomplete flaps (P = 0.02); flap buttonholes may be more likely in eyes that have undergone previous surgery. Complication rates can be reduced as the surgical team gains experience.

Astigmatism↗
PubMed1999

Visual acuity outcomes of patients 50 years of age and older with high myopia and untreated choroidal neovascularization.

OBJECTIVE: To evaluate visual outcomes of untreated submacular choroidal neovascularization (CNV) in patients 50 years of age and older with high myopia. DESIGN: Retrospective observational case series. PARTICIPANTS: Twenty-two eyes in 22 patients were studied. All were 50 years of age and older with myopia of 6.0 diopters (D) or greater or an axial length of 25.5 mm or greater. Patients had untreated CNV documented by clinical examination and fluorescein angiography at two medical centers between 1986 and 1997. INTERVENTION: Demographic and clinical data were abstracted from patients' medical records. MAIN OUTCOME MEASURE: Visual acuity at 1 year after CNV diagnosis. RESULTS: The study included 22 eyes of 22 patients (mean age, 63.1 years; mean refraction, -11.0 D). Baseline visual acuity (VA) in the study eye was 20/40 or greater in 2 (9%) patients, 20/50 to 20/150 in 9 (41%) patients, and 20/200 or less in 11 (50%) patients. Drusen were present in seven (32%) eyes, and lacquer cracks were noted in ten (45%) eyes. Mean refractive error was -7.0 D for patients with drusen and -12.5 D for patients without drusen. Choroidal neovascularization was less than 0.25 disc diameters (DD) in 11 (50%) eyes, 0.25 to 0.5 DD in 5 (23%) eyes, and greater than 0.5 DD in 6 (27%) eyes. Visual acuity in the study eye 1 year after CNV diagnosis was 20/40 or greater in 3 (14%) patients, 20/50 to 20/150 in 3 (14%) patients, and 20/200 or less in 16 (73%) eyes. The presence of drusen was significantly associated with older age and a lower degree of myopia but was not associated with size of the CNV or visual acuity outcome. CONCLUSION: When compared to patients younger than 50 years of age with high myopia and CNV reported in previous publications, the patients in the current series generally have poorer visual outcomes.

Aged↗
PubMed2006

[Familial primary pulmonary hypertension revealed by the association of bilateral chemosis, subacute myopia, and exophthalmos].

PURPOSE: To report a rare case of primary pulmonary hypertension (PPH) revealed by a relapsing chemosis, exophthalmos, and subacute myopia. PATIENTS AND METHODS: A 46-year-old woman presented with recurrent bouts of chemosis, exophthalmos, and subacute myopia. Her visual troubles were triggered by physical effort. She had a history of a longstanding high blood pressure that was noncompliant to all conventional hypotensive therapy. Automated refraction under cycloplegia showed recent myopia. At observation she had a bilateral, moderate chemosis. Hertel exophthalmometer measured a symmetric exophthalmos of 23 mm. Intraocular pressure was 20 mmHg OD and 24 mmHg OS. Eye fundus was strictly normal. RESULTS: Laboratory analysis showed no thyroid or inflammatory disease. HIV serology was negative as were antinuclear antibodies. Orbital CT confirmed the axial, symmetric exophthalmos. Echocardiogram brought out the diagnosis of PPH. Genetic studies by PCR localized the BMPR2 mutation that is characteristic of the familial type of PPH. Symptoms decreased under treatment. DISCUSSION: PPH is a rare disease caused by thickening of the arteriolar walls in the pulmonary bed, which results in a right-heart hypertension with venous stasis. Many authors have reported different posterior segment diseases secondary to PPH. However, anterior segment manifestations are extremely rare. These may be caused by a ciliary body congestion and retrobulbar vasodilatation. CONCLUSION: The association of chemosis, exophthalmos, and subacute myopia is unusual in PPH. We recommend keeping in mind the PPH as a differential diagnosis in those cases, especially in patients who suffer from high blood pressure.

Conjunctival Diseases↗
PubMed1997

Basic fibroblast growth factor, its high- and low-affinity receptors, and their relationship to form-deprivation myopia in the chick.

Form deprivation myopia in chickens is a widely accepted model to study visually-regulated postnatal ocular growth. Recently we showed that basic fibroblast growth factor-2 provides a "stop" signal for the growing eye. To understand further its action, we have localized basic fibroblast growth factor-2 and its low- and high-affinity receptors in the chicken eye, and determined the localization of basic fibroblast growth factor receptors in the inner plexiform layer with respect to that of neurotransmitter systems known to play a role in form-deprivation myopia. By immunocytochemistry and in situ hybridization, two complementary methods, we found that nearly all cells in the retina, and scleral chondrocytes, contain basic fibroblast growth factor-2 protein and messenger RNA as well as high-affinity basic fibroblast growth factor receptor protein and messenger RNA. Immunocytochemical localization of basic fibroblast growth factor-2 binding sites (a high resolution alternative to autoradiography), combined with N-glycanase and heparitinase treatment or heparin competition, revealed additional binding sites in specific synaptic layers of the inner plexiform layer and low-affinity binding sites in the choroid and optic fibre layer. Some binding sites in the synaptic layers were found to co-stratify with neurites of dopamine-, vasoactive intestinal polypeptide- or enkephalin-containing amacrine cells, suggesting that basic fibroblast growth factor-2 could modulate synaptic transmission to or from these cells. Form deprivation did not affect the levels of basic fibroblast growth factor receptor-1 messenger RNA in retina/retinal pigment epithelium/choroid (Northern blotting), but it abolished the decrease in amount of extractable basic fibroblast growth factor normally observed in the dark (Western blotting). The results are discussed with respect to previous findings on basic fibroblast growth factor-2 and basic fibroblast growth factor receptor-1 localization in the avian and other vertebrate eyes, and their relevance to form-deprivation myopia. The widespread distribution of basic fibroblast growth factor-2 and its receptor makes it impossible to predict which cells might mediate the action of basic fibroblast growth factor-2 in form-deprivation myopia. However, the alteration in amounts of extractable retinal basic fibroblast growth factor-2 in form-deprived, dark-adapted retinas, in which basic fibroblast growth factor-2 probably serves as a "stop" signal for ocular growth, is consistent with a role for basic fibroblast growth factor-2 in the regulation of ocular growth.

Animals↗
PubMed2000

Functional, psychological, and satisfaction outcomes of laser in situ keratomileusis for high myopia.

PURPOSE: To identify factors that motivate patients to seek laser in situ keratomileusis (LASIK) treatment for myopia and establish subjective levels of functional improvement and satisfaction across a range of indices after LASIK surgery. SETTING: The Corneal Diseases and Excimer Laser Research Unit, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland. METHODS: In this questionnaire-based, cross-sectional study, an anonymous 34-item questionnaire was forwarded to 50 consecutive patients in a prospective study who had had LASIK for high myopia by a single surgeon at a single center. The questionnaire used visual analog scales, anchored at each end by an adjectival descriptor. The mean preoperative myopia was -10.7 diopters +/- 4.4 (SD). Seventy-six percent of eyes (83% of patients) achieved post-LASIK uncorrected visual acuity (UCVA) of 6/12 or better; 1 eye lost 2 lines of corrected Snellen visual acuity. RESULTS: A 98% reply rate was achieved. The most common motivating factor for pursuing LASIK was to improve UCVA (88%); only 21% rated improved cosmesis as an important motive. Most patients (81% to 100%) reported functional improvement across the spectrum of visual tasks assessed, although 8.8% reported difficulty with nighttime driving. Ninety-six percent felt their UCVA was as good as anticipated, 97.9% were satisfied with the speed of visual improvement, 93.8% achieved the goals for which they had surgery, 97.9% reported an improved quality of life, and 97.9% were satisfied with the overall outcome of LASIK. CONCLUSIONS: Using an anonymous, wide-ranging questionnaire, high levels of functional improvement and satisfaction with the speed of visual recovery and outcome were reported by patients after LASIK for high myopia. Nighttime driving symptoms of variable severity were, however, noted by 8.8% of patients, despite high levels of satisfaction with other aspects of visual function.

Adult↗
PubMed2000

Photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism.

PURPOSE: To determine the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for the correction of myopia and astigmatism after penetrating keratoplasty. SETTING: Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. METHODS: Photorefractive keratectomy was performed in 16 eyes of 16 patients with postkeratoplasty myopia and astigmatism who were unable to wear glasses due to anisometropia and were contact lens intolerant. They were examined for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and corneal transplant integrity before and after surgery. RESULTS: The mean follow-up after PRK was 26.0 months +/- 15.7 (SD) (range 12 to 63 months). The mean preoperative spherical equivalent refraction of -4.47 +/- 1.39 diopters (D) was -3.39 +/- 1.84 D (P >.05) at the last postoperative visit and the mean preoperative cylinder of -5.62 +/- 2.88 D was -3.23 +/- 1.70 D (P <.05); refractive regression correlated with the amount of ablation performed. The BSCVA decreased in 3 eyes (18.8%), and the UCVA decreased in 2 (12.5%). Six eyes (37.5%) had grade 2 to 3 haze, which resolved spontaneously in 4 eyes within a relatively long time but caused a decrease in BSCVA in 2 (12.5%). Two of the eyes (12.5%) had a rejection episode after PRK and were successfully treated with topical steroids. CONCLUSIONS: Photorefractive keratectomy to correct postkeratoplasty myopia and astigmatism appears to be less effective and less predictable than PRK for naturally occurring myopia and astigmatism. Corneal haze and refractive regression are more prevalent, and patient satisfaction is not good.

Adult↗
PubMed2001

Implantable contact lens for moderate to high myopia: short-term follow-up of 2 models.

PURPOSE: To confirm the safety, efficacy, and predictability of the surgical correction of moderate to high myopia by the ICM V3 and ICM V4 implantable contact lenses (ICLs), with emphasis on vaulting, intraocular pressure (IOP), and pigment dispersion. SETTING: University Eye Hospital, Lausanne, Switzerland. METHODS: Thirty-two eyes had implantation of an ICL. In 22 eyes with a mean spherical equivalent (SE) of -11.5 diopters (D), the target was emmetropia; in 10 eyes with a mean SE of -22.3 D, the goal was a reduction in the myopia. Nineteen eyes received the ICM V3 ICL and 13, the ICM V4 ICL. The mean follow-up was 7.4 months. RESULTS: The mean postoperative SE in the 32 eyes was -2.16 D. Best spectacle-corrected visual acuity was maintained or improved in all eyes. In the 22 eyes targeted to achieve emmetropia, 10 (45%) were within +/-1.00 D; 15 (68%) had an uncorrected visual acuity of 20/40 or better and 4 (18%), of 20/20 or better. Vaulting of the ICL over the crystalline lens was more pronounced with the V4 than with the V3, and the difference was statistically significant. Subtle, localized anterior subcapsular opacification was encountered in 4 eyes. In 3 of them, the ICL (model V3) vaulting was minimal and 1 ICL (model V4) did not show any vaulting. Eighteen eyes had an IOP higher than the preoperative level, and the difference was statistically significant. No correlation was seen between final IOP and vaulting. Pigment dispersion on the ICL did not appear to be related to vaulting or ICL thickness. CONCLUSION: Implantation of an ICL was effective in correcting moderate to high myopia of up to -17.50 D. Although the procedure appears to be safe, the predictability of the refractive outcome must be improved. The new generation of ICLs for myopia (ICM V4) offers a better vault over the crystalline lens than the older models (ICM V3), which should decrease the risk of cataract. No explanation was found for the IOP increase in several eyes 3 months or more after surgery.

Adult↗
PubMed2001

Safety and predictability of laser in situ keratomileusis enhancement by flap reelevation in high myopia.

PURPOSE: To evaluate the safety and predictability of laser in situ keratomileusis (LASIK) retreatment following primary procedures for high myopia and astigmatism. SETTING: Corneal Diseases and Excimer Laser Research Unit, Department of Ophthalmology, University of Dundee, Dundee, United Kingdom. METHODS: This prospective observational study of retreatment comprised a cohort of 109 eyes having primary LASIK for high myopia and astigmatism with a spherical equivalent (SE) of -9.70 diopters (D) +/- 4.06 (SD). Twenty-four eyes (22%) with an initial myopic SE of -9.83 +/- 3.50 D, a comparable subset of the entire group (P < .05), had retreatment for residual myopia (-3.02 +/- 2.17 D) to improve uncorrected visual acuity (UCVA) by reelevating the corneal flap and ablating the stromal bed. RESULTS: The mean follow-up after retreatment was 12.8 +/- 5.1 months (range 1.5 to 24 months; 19 eyes >/=6 months, 13 eyes > or = 12 months). The mean myopic SE was reduced to +0.53 +/- 0.62 D at 1 week, +0.05 +/- 0.50 D at 1 month, +0.30 +/- 0.50 D at 6 months, and +0.18 +/- 0.42 D at the latest follow-up, 12.8 months. At the latest review, 62% of eyes were within +/-0.50 D of emmetropia and 100% were within +/-1.00 D. The mean refraction did not alter statistically between 1 week and subsequent times. The mean UCVA improved from 6/30 prior to retreatment to 6/9 at the latest follow-up. Uncorrected visual acuity of 6/6 or better, 6/9 or better, and 6/12 or better was achieved by 33.0%, 75.0%, and 95.8% of eyes, respectively. No significant complications that led to a loss of best corrected visual acuity were encountered, although retreatment procedures were more uncomfortable than primary procedures and self-limiting; epithelial ingrowth that did not threaten vision was common, and 2 patients complained of nighttime visual symptoms. CONCLUSIONS: Retreatment of residual myopia by reelevating the flap was relatively safe and predictable, with a low risk of sight-threatening complications. However, longer term studies may be required to detect late complications.

Adult↗
PubMed2001

Laser in situ keratomileusis with the VISX Star laser for myopia over -10.0 diopters.

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for myopia over -10.00 diopters (D). SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 332 eyes of 183 patients having LASIK with the VISX Star laser to correct myopia of -10.00 to -18.00 D. The eyes were divided into 3 groups according to the preoperative refraction: Group A (n = 208), -10.00 to -11.90 D; Group B (n = 94), -12.00 to -14.00 D; Group C (n = 30), -14.10 to -18.00 D. The mean follow-up was 12.0 months +/- 5.6 (SD) (range 6 to 37 months). RESULTS: Overall, the mean spherical equivalent decreased 96%, from -11.69 +/- 1.46 D preoperatively to -0.37 +/- 0.80 D postoperatively. The mean astigmatism decreased 72%, from 1.66 +/- 1.22 D to 0.46 +/- 0.53 D. At the last visit, 84.0% of eyes were within +/-1.00 D of emmetropia and 96.4% were within +/-2.00 D. An overcorrection of more than +1.00 D was experienced by 1.8% of patients. The uncorrected visual acuity (UCVA) was 20/20 or better in 45.8% of eyes and 20/40 or better in 89.5%. Six eyes (1.8%) lost 2 or more lines of best corrected visual acuity; this included 1 eye in which iatrogenic keratectasia developed 18 months after LASIK retreatment. Retreatment was done in 37.0% of eyes at a mean of 6.3 +/- 5.3 months (3 to 32 months) after the initial treatment. At the last examination, 86.0% of eyes in Groups A and B and 70.0% in Group C were within +/-1.00 D of emmetropia. A significant difference was found between Groups A and C (P =.032). The UCVA was 20/20 in 52.0% of Group A eyes, 38.0% of Group B eyes, and 23.0% of Group C eyes. The difference between Groups A and C was significant (P =.001), but the difference between Groups A and B was not (P =.055). CONCLUSIONS: In this study, LASIK was effective in correcting myopia up to -14.00 D. The efficacy, predictability, and safety were significantly less in eyes with myopia greater than -14.00 D.

Adult↗
PubMed2001

Laser in situ keratomileusis with a scanning excimer laser for the correction of low to moderate myopia with and without astigmatism.

PURPOSE: To evaluate the safety and effectiveness of and patient satisfaction with laser in situ keratomileusis (LASIK) performed with a scanning excimer laser by experienced surgeons to correct low and moderate levels of myopia and astigmatism. SETTING: Clinique Laservue, Montreal, Quebec, Canada. METHODS: A consecutive series of 125 patients (236 eyes) with myopia of -0.5 to -7.0 diopters (D) and cylinder less than 2.5 D were enrolled in this single-center prospective clinical trial. The patients were treated with LASIK and followed for 6 months. The System-ALK Automated Corneal Shaper microkeratome (Bausch & Lomb Surgical) with a 180 microm thickness plate and the Technolas 217 excimer laser (Bausch & Lomb Surgical) with PlanoScan software for the stromal ablation were used in all procedures. Since this version of PlanoScan tended to undercorrect, a mean of 14.7% was added to the standard nomogram. Patient satisfaction was assessed by questionnaires administered preoperatively and 1 and 6 months postoperatively. Retreatments for enhancement were not performed during the 6-month follow-up. RESULTS: Six months after LASIK (86.4% follow-up), the mean postoperative manifest spherical equivalent was +0.02 D +/- 0.64 (SD) compared with a preoperative mean of -4.01 +/- 1.59 D. The uncorrected visual acuity was 20/40 or better in 94.6% of eyes and 20/20 or better in 81.9%. A total of 91.2% were within +/-1.0 D of emmetropia and 73.0% were within +/-0.5 D. Only 2 eyes were overcorrected by >1.0 D. Of the eyes with astigmatic myopia, 86.8% were within +/-1.0 D of the intended cylinder correction (by vector analysis) and 73.0% were within +/-0.5 D. The refractions were generally stable after 1 month, and the change in refraction between postoperative examinations was within +/-0.5 D in 88.0% of eyes. A 1-line decrease in best spectacle-corrected visual acuity was seen in 11.3% of eyes, and no eye lost more than 1 line. An increase of 1 or 2 lines was seen in 45.1%. No intraoperative problems occurred, and the interface was clear in all eyes. At 6 months, most symptoms present significantly more frequently than preoperatively were "mild"; none were "marked" or "severe." A total of 90.5% of eyes were reported with marked to extreme improvement in the overall quality of vision, and 99.0% of patients said they would choose LASIK surgery again. CONCLUSIONS: Mild to moderate myopia, with and without astigmatism, was corrected safely, effectively, and predictably with a high degree of patient satisfaction using LASIK with a scanning excimer laser and the System-ALK Automated Corneal Shaper.

Adult↗
PubMed2003

Intraocular lens power calculation formulas in Chinese eyes with high axial myopia.

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation formulas in Chinese eyes with high axial myopia. SETTINGS: Department of Ophthalmology, Tuen Mun Hospital, Hong Kong, China. METHODS: This retrospective study reviewed 125 Chinese patients with high myopia and axial lengths (ALs) longer than 25.0 mm who had cataract surgery during the year 2000. Eyes with pathology or operative complications affecting the refractive status and those with missing data were excluded. In each case, the power of the implanted IOL was used to calculate the predicted postoperative refractive error by 4 IOL power calculation formulas: SRK II, SRK/T, Holladay 1, and Hoffer Q. The predictive accuracy of the formulas was analyzed by comparing the difference between the "actual" and "predicted" postoperative refractive errors. The Student t test was used for statistical analysis. The performance of the formulas in subcategories of long AL was also tested. RESULTS: One hundred twenty-five eyes (110 patients) were studied. Thirty-seven eyes (29.6%) were excluded. The Hoffer Q, Holladay 1, and SRK/T formulas showed a slight tendency toward resultant hyperopia, with a mean of +0.36 diopters (D), +0.53 D, and +0.74 D, respectively. The SRK II caused the largest hyperopic error, with a mean of +1.47 D. All 4 formulas caused a refractive error shift toward myopia in the subcategories of AL >28.0 mm, minus-power IOL, and extracapsular cataract extraction (ECCE). CONCLUSIONS: In Chinese eyes with high axial myopia with an AL longer than 25.0 mm, the 4 formulas caused a slight postoperative hyperopic refractive error that was less in eyes with a minus-power IOL or an AL longer than 28.0 mm and in those that had ECCE. The Hoffer Q formula provided the best predictive result, and Holladay 1 and SRK/T were comparable in IOL power calculation. The SRK II was the least accurate in all subgroups.

Adult↗
PubMed2003

Combined laser in situ keratomileusis and radial keratotomy for the treatment of moderate to high myopia.

PURPOSE: To evaluate the results of combining laser in situ keratomileusis (LASIK) and radial keratotomy (RK) for the correction of moderate to high myopia. SETTING: Corneal Consultants of Colorado, Littleton, Colorado, and International Eye Care Laser Vision Center, Houston, Texas, USA. METHODS: In a retrospective 2-surgeon interventional case series, outcomes in 60 eyes of 41 patients with moderate to high myopia were reported. All eyes had LASIK using a Visx Star S2 or Summit Apex Plus((R)) excimer laser. Residual myopia was treated with RK. RESULTS: Of the 54 eyes corrected for distance, the mean refractive spherical equivalent was -8.09 diopters (D) preoperatively and -0.43 D after LASIK and RK. The mean follow-up was 15.4 months. At the last visit, the uncorrected visual acuity was 20/20 in 22 eyes (41%), 20/25 in 36 eyes (67%), and 20/40 in 51 eyes (94%). No eye lost 2 or more lines of best spectacle-corrected visual acuity. CONCLUSIONS: Many patients previously considered poor refractive surgery candidates because of their degree of myopia or corneal thickness could be offered this safe and effective combined refractive technique.

Adult↗
PubMed1996

Effect of optic zone size on the outcome of photorefractive keratectomy for myopia.

PURPOSE: To determine the effect of optic zone size on the outcome of photorefractive keratectomy (PRK) for myopia. SETTING: Department of Ophthalmology, Samsung Medical Center, Seoul, Korea. METHODS: Twenty patients, 10 with myopia under 6.00 diopters (D) and 10 with myopia over 6.00 D, had bilateral PRK with identical dioptric corrections in both eyes. One eye was treated with a 5.0 mm diameter optic zone and the other with a 6.0 mm diameter optic zone. An identical postoperative eyedrop regimen was used. During the 6 month follow-up, changes in refraction, uncorrected visual acuity, and corneal anterior stromal haze were evaluated. At the end of the follow-up, patients completed a questionnaire on night-vision disturbance, foreign-body sensation, tenderness, and preference. RESULTS: Two weeks postoperatively, eyes with a 5.0 mm optic zone had a significantly greater hyperopic shift than those with a 6.0 mm optic zone. Eyes with myopia over 6.00 D and a 6.0 mm optic zone had significantly faster recovery of uncorrected visual acuity at 2 and 12 weeks. There was no increased anterior stromal haze in the 6.0 mm optic zone eyes, despite the deeper stromal ablation. Night-vision problems were more prevalent in the 5.0 mm optic zone group, which also had a greater incidence of ablation decentration. CONCLUSION: A 6.0 mm optic zone for myopic PRK seems to produce better outcomes. Further evaluation of long-term results is needed.

Adult↗
PubMedDate not supplied

Efficacy and safety of excimer laser photorefractive keratectomy and radial keratotomy for bilateral myopia.

PURPOSE: To compare the safety and efficacy of radial keratotomy (RK) and photorefractive keratectomy (PRK) to correct myopia. METHODS: In this randomized, prospective, parallel-group study, 33 patients with bilateral myopia of 1.00 to 5.00 diopters (D) had PRK in one eye and RK in the other. The order of surgeries and treatment assignments were randomized, and the bilateral surgeries were within 1 week for each patient. Data were collected using standardized procedures. Clinical measurements and satisfaction surveys were taken in masked fashion. RESULTS: Eyes that had PRK had statistically significantly more residual myopia than RK-treated eyes at 3, 6, and 12 months postoperatively. This result was attributed to the use of an older excimer laser PRK algorithm that was used at the initiation of the study. No eye that had PRK was overcorrected by 0.50 D or more at 1 year postoperatively, while seven eyes that had RK were overcorrected by at least 0.50 D and six were overcorrected by 1.00 D. Eyes that had PRK had a statistically significant mean shift in the myopic direction between 6 and 12 months postoperatively; two RK eyes had hyperopic shifts of 1.00 D. Three RK eyes and two PRK eyes failed to achieve an uncorrected visual acuity of 20/40 or better by 12 months postoperatively. No eye lost any best corrected visual acuity. CONCLUSION: The two procedures were comparably safe and effective in treating mild to moderate myopia under this protocol. Eyes that had PRK were somewhat more myopic at 1 year after surgery, attributable to the older PRK ablation algorithm. Adoption of newer (current) laser algorithms has improved the predictability of PRK. There was also evidence of reduced variability of outcome in the PRK group. The PRK eyes did not exhibit hyperopic shifts during the 1 year follow-up.

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