Intraocular Lens Calculation after Refractive Surgery: A Long-Term Retrospective Comparison of Eight Formulas.

The aim of this study was to compare the accuracy of 8 IOL power calculation formulas for eyes post-refractive surgery. In this Retrospective study, a chart review and data analysis of post-corneal refractive surgery patients who subsequently underwent cataract surgery with IOL implantation in Tertiary surgical center, Draper, UT, USA. The surgery was done in a single surgical center in Draper, UT by one surgeon. The study was approved by the organization's ethics board. The IOL power formulas used were Barrett True K (BTK), Average Pupil Power (APP), Shammas, Haigis, Galilei, Potvin-Hill Pentacam (PVP), OCT and Barrett True K No History (BTKNH). The percent of time each formula was within ±0.5 D and ±0.75 D of refractive prediction error was calculated. Statistical analysis was performed comparing these 8 methodologies at four post-operative follow-up time points and on the summative time points. Mean follow-up time periods were: 4 weeks, 3 months, 6 months, and 12 months. A total of 64 eyes were included in the study. All IOL formulas showed a myopic trend except APP and Shammas, which showed a hyperopic trend. All tests showed a statistically significant mean absolute value difference from zero. OCT, BTKNH, and BTK had consistently high percentages within ±0.5D and ±0.75 D of refractive error. Linear mixed model analysis showed a statistically significant change in predictive value over time for all formulas. Linear mixed model analysis suggests that it is inadequate to evaluate the performance of IOL power formulae in the short term. Longer-term follow-up is needed to determine accuracy as several factors can result in refractive changes greater than 3 months postoperatively. Our analysis did not demonstrate any formula that was clearly superior to the other methods for predicting IOL power at any time point.

Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series.

The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA.

Special Care in Lichen Planus Patients Undergoing LASIK: A Review Article.

Laser-Assisted in Situ Keratomileusis (LASIK) is a common surgery for the correction of refractive errors. The majority of patients who undergo this procedure often have excellent results. However, uncontrolled autoimmune disorders and dry eye have both been listed as contraindications to this surgery. Lichen planus (LP) is an autoimmune, inflammatory disorder that characteristically affects mucocutaneous membranes. The etiology is unknown, but it most commonly affects middle-aged adults and presents with bilateral, purple papules. Clinical presentation is used to diagnose the condition, and a punch biopsy is confirmatory. LP may present with multiple different symptoms depending on the type, with ocular manifestations being rare. Multiple viruses and autoimmune conditions have been associated with the disorder, and physicians should take care when gathering a full history of the patient. Exacerbation of symptoms may happen if mood disorders such as depression and anxiety are not well controlled. There are several additional factors physicians must carefully consider before recommending LASIK to patients with LP. These include lichenoid reactions, current medications, and past or present ocular lesions. LASIK may be carefully considered in patients with well-controlled LP in the absence of ocular manifestations. Patients with ocular LP are not candidates for LASIK.

Visual Prognosis after Explantation of a Corneal Shape-Changing Hydrogel Inlay in Presbyopic Eyes.

The purpose of this case series is to report visual outcomes in patients who underwent explantation of the Raindrop® hydrogel corneal inlay. Retrospective chart review comprising four cases of explantation of the Raindrop® corneal shape-changing hydrogel inlay: pre-implantation, pre-explantation, and post-explantation values for uncorrected distance visual acuity, uncorrected near visual acuity, and corrected distance visual acuity (CDVA) were measured; keratometric and tomographic data were collected using the Pentacam system (Oculus, Inc). Three eyes were explanted for progressive haze after implantation that persisted even after removal; one eye was explanted due to poor visual acuity with no haze formation. All patients experienced decreased unaided and corrected distance visual acuity. Persistent increase in corneal thickness and mean keratometry was noted post-explantation. All four patients regained their original near visual acuities, but one patient had persistent one-line loss in CDVA. There are long lasting tomographic corneal changes following Raindrop inlay explantation. In addition, persistent increased corneal thickness could be related to semi-permanent changes in corneal structure and may account for residual haze experienced by patients. After explantation, patients may not return to baseline CDVA.

Comparative Analysis of LASIK Flap Diameter and its Centration Using Two Different Femtosecond Lasers.

The aim of this study was to compare the diameter, accuracy, variability, and centration with respect to the limbus of corneal flaps created by two femtosecond lasers, the VisuMax, and Wavelight FS200, for laser in situ keratomileusis (LASIK) and how these flaps affect visual outcomes. This is a retrospective chart review of flap morphology created during LASIK Surgery. Overall, 168 eyes underwent flap creation using the WaveLight FS200 laser, and on 189 eyes, the VisuMax laser was used. Of these total number, flap morphology was analyzed in a random sample of 158 eyes; 80 with the Visumax laser and 78 with the WaveLight FS200 laser. Intraoperative photos of the flaps taken by the Wavelight Allegretto EX500 were analyzed. Flap diameters and centration were measured using Adobe Acrobat Pro. All patients had visual acuity measurements including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent refraction (SE) and refractive astigmatism recorded three months postoperatively. Greater than 90% of patients in both groups achieved a UDVA of 20/20 postoperatively. The mean difference between targeted and achieved flap diameter was 0.50 +/- 0.15 mm in the VisuMax group and 0.35 +/- 0.15 millimeters (mm) in the FS200 group (P<0.01). The flap diameters of the VisuMax group were more precise with a variance of 0.024 mm compared to a variance of 0.038 mm in the FS200 group (P<0.05). VisuMax flaps were more nasally displaced (log(NA/TA) = -0.21 +/- 0.10 mm) compared to the FS200 flaps (log(NA/TA) = 0.03 +/- 0.10 mm), (P< 0.01). We concluded that both the VisuMax and FS200 created flaps larger than the preoperative targeted diameter. VisuMax created corneal flaps that had a greater degree of deviation from the targeted diameter when compared to flaps from the FS200. However, there was less variance in the VisuMax flap diameter. In addition, VisuMax flaps were more nasally displaced. There were no statistically significant differences in visual outcomes when comparing the two femtosecond lasers.

Should Patients with Hidradenitis Suppurativa Undergo LASIK?

Hidradenitis suppurativa (HS) is a relatively common chronic inflammatory disease with immune dysregulation. While eye manifestations of HS are rare, a dilemma arises when these patients seek treatment for refractive errors. Although excimer laser surgery can be safely performed in patients with autoimmune and immune-mediated inflammatory disease, there are caveats. Aside from the routine laser-assisted in situ keratomileusis (LASIK) screening tests, in some instances, we recommend additional screening tests in patients with HS, such as dry eye tests, consultation with specialists regarding HS diagnosis and treatment, careful assessment of the eyelids and periorbital structures, and thorough history of past and current lesions and treatments. After these patients undergo LASIK, careful, frequent, and long-term follow-up is necessary. Any adverse event or complication should be managed immediately. FUNDING: Research to Prevent Blindness funded the study. Hoopes Vision funded the Rapid Service Fees.

Dyskeratosis Congenita and Corneal Refractive Surgery.

Dyskeratosis congenita is a syndrome of bone marrow failure secondary to unstable telomeres. It is characterized by a range of mucocutaneous diseases. Due to premature telomere shortening, these patients have limbal stem cell deficiency leading to poor regeneration and maintenance of the cornea. Many of these patients will require hematopoietic stem cell transplant in their lifetime, which poses a significant risk for acute and chronic graft-versus-host disease with and without ocular manifestations. We advise against elective corneal refractive surgery in patients with dyskeratosis congenita due to the compounded and long-term risks of delayed healing secondary to limbal stem cell deficiency and ocular complications of graft-versus-host disease post-allogeneic hematopoietic stem cell transplant.

Keratoconus Screening in Elementary School Children.

Keratoconus is a degenerative structural disease of the cornea. Progression leads to poor acuity that is not easily correctable by standard means. New treatments, such as collagen cross-linking, lead to better long-term outcomes if performed early in the disease course. Currently, children in the USA are screened for acuity in school, but not for keratoconus. Due to the severity of the disease in children, we recommend topographic screening in elementary schools as a way to provide early detection and treatment.Funding Research to Prevent Blindness provided funding for the Rapid Service Fees.

Should I Get LASIK If I'm Breastfeeding?

Changes in keratometric values and refraction can occur during pregnancy. For this reason, changing a patient's refractive prescription or undergoing corneal refractive surgery is not recommended during pregnancy. However, the extent to which these corneal changes persist during lactation is not as well reported. Pregnancy and lactation lead to hormonal changes that affect the corneal structure. LASIK, or other types of refractive surgery, is not recommended until all of the following conditions are met: cessation of lactation, the return of regular menses, and a return to pre-pregnancy refraction. Additionally, patients should be cautioned that refractive regression may occur if they become pregnant within 1 year of LASIK. FUNDING: Research to Prevent Blindness, NY, USA.