A retrospective chart review of consecutive patients with ocular hypertension and primary open-angle glaucoma who underwent selective laser trabeculoplasty indicates that the percentage of intraocular pressure reduction after SLT was significantly greater in eyes with thinner corneas (central cornea thickness <55 μm).These patients demonstrated better IOP control for at least 30 months after SLT.
Partial correlation analysis was performed to correlate the CCT to the percentage of IOP reduction at three to 30 months after SLT. Independent samples t test was performed to compare mean percentage of IOP reduction in eyes with CCT <555 μm versus CCT ≥555 μm.
Eighty eyes of 47 patients were identified between 2002 and 2005. The partial correlation coefficient value between the CCT and percentage of IOP reduction after SLT at three months was -0.253 (p=0.025), at 12 months it was -0.22 (p=0.049), and at 30 months it was 0.301 (p=0.007). Independent samples t test showed that the mean percentage of IOP reduction in eyes with thinner corneas (CCT<555 μm) was greater than in thicker corneas (CCT ≥555 μm) at three-, six-, nine-, 12- and 30-months post-SLT (p<0.05).
Shazly T, Latina M, Dagianis J, Chitturi S.
Comparing Image Sharpness Across Five IOLs
This laboratory investigation from researchers at the Pepose Vision Institute assessed the through-focus polychromatic image sharpness of five FDA-approved presbyopia-correcting intraocular lenses and concluded that differing IOL design strategies to increase depth of field are associated with quantifiable differences in image sharpness at varying vergences and pupil sizes.
A 1951 U.S. Air Force resolution target was imaged through Crystalens AO (AO), Crystalens HD (HD), aspheric ReSTOR +4 (R4), aspheric ReSTOR +3 (R3) and Tecnis Multifocal Acrylic (TMF) IOL in a model eye and captured digitally for each combination of pupil diameter and object vergence. The sharpness of each digital image was objectively scored using a two-dimensional gradient function.
AO had the best distance image sharpness for all pupil diameters and was superior to the HD. With a 5-mm pupil, the R4 distance image sharpness was similar to the HD, and at 6 mm the TMF was superior to the HD, R3 and R4. The R3 moved the near focal point farther from the patient compared to the R4, but did not improve image sharpness at intermediate distances and showed worse distance and near image sharpness. Consistent with apodization, the ReSTOR IOLs displayed better distance and poorer near image sharpness as pupil diameter increased. TMF showed consistent distance and near image sharpness across pupil diameters and the best near image sharpness for all pupil diameters.
Am J Ophthalmol 2012;154:20-28
Pepose J, Wang D, Altmann G.
iStent Plus Cataract Surgery Creates Better IOP Control
Researchers from the iStent Study Group conclude that patients with combined single trabecular micro-bypass stent and cataract surgery had significantly better IOP control on no medication through 24 months than patients having cataract surgery alone. The group conducted a prospective, randomized, controlled multicenter clinical trial across 29 investigational sites in the United States in order to assess the long-term safety and efficacy of a single trabecular micro-bypass stent with concomitant cataract surgery versus cataract surgery alone.
Eyes with an unmedicated intraocular pressure of 22 mmHg or higher and 36 mmHg or lower were randomly assigned to have cataract surgery with iStent trabecular micro-bypass stent implantation (stent group) or cataract surgery alone (control group). Patients were followed 24 months postoperatively.
The incidence of adverse events was low in both groups through 24 months of follow-up. At 24 months, the proportion of patients with an IOP of 21 mmHg or lower without ocular hypotensive medications was significantly higher in the stent group than in the control group (p=0.036). Overall, the mean IOP was stable between 12 months and 24 months (17 mmHg ±2.8 [SD] and 17.1 ±2.9 mmHg) in the stent group but increased (17 mmHg ±3.1 mmHg to 17.8 ±3.3 mmHg) in the control group. Ocular hypotensive medication was statistically significantly lower in the stent group at 12 months; it was also lower at 24 months, although the difference was no longer statistically significant.
J Cataract Refract Surg 2012;38:1339-1345
Craven E, Katz L, Wells J, Giamporcaro J.
Chronic Hypotony Associated With Boston KPro-1
Researchers from the Wilmer Eye Institute conducted a retrospective case series on the occurrence of chronic hypotony as a complication following Boston keratoprosthesis type one implantation, concluding that chronic hypotony can be a significant complication of Boston KPro-1 implantation and should be assessed carefully in eyes with retroprosthetic membranes.
The medical records of all patients undergoing KPro implantation between January 2004 and November 2010 at the Wilmer Eye Institute were reviewed. Patients who developed chronic hypotony following Boston KPro-1 implantation not attributable to anatomic problems (e.g., retinal detachment, overfiltering glaucoma tube shunts, tissue necrosis with aqueous leak) or other causes were identified. Demographics and pre-, intra- and postoperative clinical findings were analyzed, and light microscopic examination of an enucleated globe, as well as fibrous retroprosthetic membranes excised at the time of vitrectomy from another patient, was performed.
Sixty-eight eyes received KPro-1 implantation over the study period. Six eyes experienced chronic hypotony, with a median time of 18.5 months between KPro-1 implantation and the onset of hypotony. The incidence of chronic hypotony in this series was calculated to be 3.7 percent at one year and 13.3 percent at two years. Of the six eyes that developed chronic hypotony, five had a previous history of glaucoma or ocular hypertension, but only three had a glaucoma drainage implant. All eyes progressing to chronic hypotony were noted to have a retroprosthetic membrane prior to the onset of hypotony. Cox regression modeling demonstrated an increased risk of chronic hypotony in eyes with retroprosthetic membrane (p<0.01) but no increase in risk for older patients (p>0.5) or previous history of multiple donor corneal transplants (p>0.5).
Am J Ophthalmol 2012;154:266-271
Dokey A, Ramulu P, Utine C, Tzu J, et al.
Eyelid Surgery After Boston KPro Implantation
A retrospective chart review at two U.S. universities showed that a significant percentage of patients who undergo Boston KPro implantation require subsequent eyelid surgery. The study examined the frequency, nature and outcomes of oculoplastic procedures in all patients with Boston KPro-1 procedures performed at the University of Illinois at Chicago between December 2006 and September 2010 and all KPro-1 and KPro-2 procedures performed at the University of Iowa between December 2008 and October 2010 (KPro-1, 120 eyes and KPro-2, two eyes). Twenty-one (17.2 percent) of the 122 eyes required subsequent eyelid alterations. Chemical burn was the most common preoperative corneal diagnosis (eight of 21; 38.1 percent). A variety of oculoplastic procedures were performed; the most common procedure was a permanent lateral tarsorrhaphy. Seventeen (81 percent) of 21 KPro eyes that underwent oculoplastic procedures maintained the KPro at an average of 12.4 months of follow-up.
Ophthal Plast Reconstr Surg 2012;28:286-288
Baker M, Krakauer M, Gupta S, de la Cruz J, et al.
Declining Medicare Payment Affects Punctal Plug Insertions
Researchers have determined that although the frequency of dry-eye syndrome diagnosis in the Medicare population has increased over time, first-time punctal plug insertion rates, especially within the first year following DES diagnosis, have declined coincidentally with the increasing presence of a medical alternative and declining Medicare payments.
Cases of DES diagnoses and punctal plug insertions among Medicare beneficiaries were identified from Medicare 5% Part B from 1994 to 2008, using a three-year look-back. Dry-eye syndrome diagnoses and punctal plug insertion codes were ascertained from the ICD and CPT codes. Medicare payment data were obtained from the Centers for Medicare & Medicaid Services from 1994 to 2008 for punctal plug insertion. Rates were calculated for both the incidence of DES and the use of punctal plugs.
From 2001 to 2008, inflation-adjusted Medicare reimbursement for punctal plug insertion decreased 55.1 percent, whereas the Medicare population-adjusted incidence of dry-eye diagnosis increased 23.3 percent. Nine percent of individuals diagnosed with DES between 1991 and 2008 underwent punctal plug placement with a mean of two plugs placed per patient. Total punctal plug replacement increased 322.2 percent between 1994 and 2003, and then reached a plateau. First-time punctal plug insertion rates within 365 days of DES diagnosis increased 11.8 percent from 1994 to 2002, and then declined 47 percent from 2002 to 2008.
Ophthal Plast Reconstr Surg 2012;28:289-293
Chi S, Acquah K, Richard M, Lee P, Sloan F.
Disparities In Diagnostic Technologies for Glaucoma
In this prospective cross-sectional study, doctors from New York argue that causes of disagreement among three glaucoma diagnostic techniques (standard automated chromatic perimetry, the multifocal visual evoked potential technique, optical coherence tomography) can be explained by the known limitations of each technique and inter-individual variability. This suggests that agreement among diagnostic tests may be better than summary statistics suggest and that disagreements between tests do not indicate discordance in the structure-function relationship.
One hundred thirty-eight eyes of 69 patients with glaucomatous optic neuropathy were tested using SAP, the mfVEP and OCT. Eyes with worse mean deviations had better agreements among tests than did eyes with better MD. For the 94 of 138 hemifields with abnormalities of the more advanced eyes, the three tests were consistent in showing the same hemifield abnormality in 50 hemifields (53 percent) and at least two tests were abnormal in 65 of the 94 hemifields (69 percent). The potential explanations for the false-negative results fell into two general categories: inherent limitations of each technique to detect distinct features of glaucoma and individual variability and the distribution of normative values used to define statistically significant abnormalities.
Arch Ophthalmol 2012;130:833-840
De Moraes C, Liebmann J, Ritch R, Hood D.