Comparison of 10-2 and 24-2 Perimetry to Diagnose Glaucoma Using OCT as an Independent Reference Standard
Onyekaba NA., Estrela T., Naithani R et al.
Ophthalmology Glaucoma 2023; 6: 187-197
Question: How do 24-2 and 10-2 compare as diagnostic strategies across the spectrum of glaucoma severity?
Glaucoma has historically been felt to affect the peripheral visual field prior to the central field, and as such, the 24-2 visual field has typically been favored as monitoring strategy in all but advanced stage disease, where emphasis on central field loss leads to wide spread use of 10-2. More recent studies call this into question and suggest that macular changes may occur early in the disease process, a concept that is concerning for early monitoring as the 24-2 SITA devotes so few data points to fixation. The authors of this study used both circumpapillary retinal nerve fiber layer thickness and macular ganglion cell layer thickness as determined by optical coherence tomography to stage glaucoma by structural loss and then compared the ability of indices of both the 24-2 and 10-2 to match staging. More than 1300 paired visual fields of 339 patients were used.
Clinical value/Implications
In all stages of disease (as determined by either circumapapillary retinal nerve fiber layer or macular ganglion cell layer defects) along all visual field indices, 24-2 performed better as a diagnostic strategy than 10-2. Even when disease severity was defined by macular ganglion cell layer, which would generally indicate increasing sensitivity of the more central field–specific 10-2, the 24-2 performed better. This difference was most prominent in early stages, and the two tests performed most similarly at late stages. A limitation of this study was that the definition of different stages of glaucoma was purely based on structural changes on optical coherence tomography. As no formal consensus for staging glaucoma based on optical coherence tomography deficits exists, the authors simply divided the optical coherence tomography into four groups (1 being mildest tissue loss on optical coherence tomography, 4 being the most severe). This obviously will not correlate precisely with clinical staging, which often relies partially on visual field defects. Furthermore, best corrected visual acuity worse than 20/40 was an exclusion criterion. In theory at least, patients with more central involvement, and thus worse best corrected acuity, may be predicted to have more to gain with the central emphasis of 10-2. Finally, the authors conclude that although 24-2 outperformed 10-2, neither test was very sensitive at detecting early deficits, and so, they point out that greater reliance on structural analysis may be appropriate for early-stage disease.
Fellow-Eye Retinal Detachment Risk as Stratified by Hyaloid Status on OCT
Wallsh JO, Langevin ST, Kumar A, et al. Ophthalmology 2023;130:624-630
Question: Can evaluation of the hyaloid status by optical coherence tomography at the time of a rhegmatogenous retinal detachment predict the risk of a rhegmatogenous retinal detachment occurring in the fellow eye?
Background/Summary of Findings
This was a retrospective chart review of patients having a diagnosis of a rhegmatogenous retinal detachment whose bilateral posterior hyaloid status was captured on optical coherence tomography at the time of the unilateral rhegmatogenous retinal detachment. Optical coherence tomography imaging involved obtaining a 20° by 15°/6 mm macular scan with 19 sections. Additionally, baseline characteristics, including lattice degeneration, refractive error, prior ocular laser, lens status, and family history of retinal detachment, were recorded. The posterior hyaloid status was defined by the presence or absence of a posterior vitreous detachment. The primary outcome measurements were the development of a fellow eye rhegmatogenous retinal detachment and the time it took to develop after the initial rhegmatogenous retinal detachment in the first eye. The authors also evaluated the development of and time to develop a posterior vitreous detachment in eyes whose posterior hyaloid face was attached at the initial optical coherence tomography capture.
Over 5.7 years, 1049 patients with an initial rhegmatogenous retinal detachment were followed; 14.6% developed a sequential rhegmatogenous retinal detachment in the fellow eye. Optical coherence tomography from 582 fellow eyes was available; 229 eyes had posterior vitreous detachments and 353 had attached hyaloid. rhegmatogenous retinal detachments occurred in only 3% of eyes having a posterior vitreous detachment but occurred in 7.9% of those with hyaloid attachment. In eyes in which a posterior vitreous detachment developed, 23.7% (28 eyes) were also found to have concurrent rhegmatogenous retinal detachment, and 21 eyes (17.8%) were found to have retinal tears (these were treated prior to any development of rhegmatogenous retinal detachment). Baseline hyaloid attachment carried a 160% risk of fellow eye rhegmatogenous retinal detachment, and baseline lattice degeneration carried a 50% increased risk. The authors noted that the retrospective nature of the study was a limitation and that although macular scans are often sufficient to assess when a posterior vitreous detachment has achieved completion, additional confirmation with optic nerve scans is optimal. Additionally, rhegmatogenous retinal detachments can occur even without complete posterior vitreous detachment owing to underlying peripheral retinal pathologies, so separation of the hyaloid face on macular scans does not preclude the development of rhegmatogenous retinal detachment.
Clinical Value/Implications
Optical coherence tomography is a widely used technology in clinical practice, and this study shows the possible prognostic use of macular scans in fellow eyes having already undergone a rhegmatogenous retinal detachment. Although a rhegmatogenous retinal detachment can be a result of multiple factors, the ability to simply and noninvasively assess the attachment or detachment of the hyaloid at the macula may enhance our ability to predict the likelihood of a rhegmatogenous retinal detachment and subsequently detect retinal damage early enough to prevent any threat to vision.
Haptic Erosion Following Sutureless Scleral-fixated Intraocular Lens Placement
Paktravan P., Patel V., Chau V. et al. Ophthalmology Retina 2023; 333-337.
Question: What is the prognosis of a haptic erosion following placement of a sutureless intrascleral fixated intraocular lens?
Background/Summary of Findings
Intraocular lens placement in eyes with widely compromised capsular bag complexes has traditionally been accomplished with anterior chamber intraocular lenses. Potential compromise of both angle anatomy and corneal endothelium, with subsequent risk of glaucoma and corneal decompensation, have been long-term risks with anterior chamber intraocular lenses and have led to exploration of alternative techniques of intraocular lens fixation in these eyes. Sutureless intrascleral fixation, where the haptics of a three-piece intraocular lens are embedded through the scleral wall, presents one such alternative and has been gaining popularity steadily since Yamane et al. published the seminal report on their technique 6 years ago. Haptic erosion externally through the conjunctiva is a possible complication of sutureless intrascleral fixated intraocular lenses.
This multicenter review of sutureless intrascleral fixated intraocular lenses examined haptic erosions from nine different centers among 19 different surgeons and assessed the repair and prognosis of this erosion.
Clinical value/Implications
Forty-seven percent of patients suffering sutureless intrascleral haptic erosion were asymptomatic and discovered serendipitously at routine examination, whereas the remainder of the cohort had symptoms of pain or photophobia, blurred vision, or redness. Median time from surgery to haptic erosion was 80 days, although it occurred as late as nearly 3 years later in one eye. In general, repair involved trimming the offending haptic and either reinserting or repositioning it. Ninety-five percent of cases were stable following repair. The single case that was not stable was eventually replaced with an anterior chamber intraocular lens. Of note, eyes with a history of previous conjunctival surgery had a greater risk of haptic erosion, perhaps indicating greater friability of the conjunctiva in these eyes, and so may present a greater initial risk of haptic erosion with sutureless intrascleral fixation. Of note, best corrected visual acuity did not reduce significantly following repair of the offending haptic.
As cataract surgery is the most frequently comanaged ophthalmic surgery by optometrists, being aware of variations in technique and risks associated with these variations is worthwhile for optometry. Sutureless intrascleral fixation is a growing technique in complicated eyes needing intraocular lens placement. Furthermore, being aware of haptic erosion, which may occur years after these surgeries, and its management is critical for all optometrists comanaging these eyes.
Clinical Trial for Autologous Cultivated Limbal Epithelial Cell Sheet Transplantation for Patients With Limbal Stem Cell Deficiency.
Oie Y, Sugita S, Yokokura S et al. Ophthalmology 2023 130:608-14
Question: Are sheets of cultivated autologous limbal stem cells viable treatments for limbal stem cell deficiency?
Background/Summary of Findings
At its surgical stages, limbal stem cell deficiency is a difficult problem to treat with guarded surgical prognoses. In the case of allogenic transplants (i.e., those derived from nonhost organisms of the same species), the requirement for potent immune modulatory therapy to prevent allograft rejection of the nonimmune privileged limbal tissue remains a real barrier to treatment. Host-derived limbal transplants avoid this immunologic burden but are limited by the fellow eye’s ability to withstand substantial areas of limbal tissue. This small, Japan-based, multicenter, uncontrolled study examined clinical response to sheets of autologous (patient derived) cultivated limbal epithelial cell in patients with limbal stem cell deficiency. In this study, 3 mm2 of limbal stem tissue was removed from the uninvolved fellow eye. This tissue was then cultivated into a sheet. The sheet was subsequently transplanted onto the diseased eye after surgical dissection of conjunctivalized corneal epithelium and placed under a bandage soft contact lens.
Sixty percent of patients responded positively to treatment with follow-up over 2 years. Evaluation of clinical response was performed by a second- or third-party cornea specialist who analyzed slit lamp and fluorescein photos anonymously and randomly. This measure compares favorably to other cultivated limbal stem cell treatment reviews and is superior to allogenic limbal stem cell therapy, in which improvement over 2 years was determined in one review to be 15%.
Clinical value/Implications
Cultivated limbal stem cell sheets are interesting approaches for the future management of limbal stem cell dysfunction. This technique appears superior to allogenic (donor derived) approaches because it avoids most of the immunologic implications of transplanting foreign limbal cells and is minimally disruptive to the donor eye as only a small zone of limbus is removed. However, it is important to be aware that this approach is only available for patients with unilateral pathology as the fellow eye’s limbus needs to be healthy enough to donate 3 mm2 of limbus tissue and so would not be an option for patients with severe bilateral disease, as seen with congenital aniridia. Furthermore, availability of this process is currently limited to Japan.
Mendelian Randomization Implicates Bidirectional Association Between Myopia and Primary Open-Angle Glaucoma or Intraocular Pressure
Chong R.S., Henton L, Iwagami M. et al.Ophthalmology 2023;130:394-403
Question: Is there a causal genetic link between myopia and glaucoma or myopia and increased intraocular pressure?
Background/Summary of Findings
Possible associations between myopia and glaucoma and myopia and elevated intraocular pressure have been made previously; however, several studies of these associations have called them into question. Further, variations from normal retinal nerve fiber layer and subjective visual field testing among highly myopic eyes may confound the ability to differentiate from truly glaucomatous optic neuropathy, making any clinical relationship difficult to establish.
Mendelian randomization involves establishing a causal relationship between variation of normal genes within a population, exposure to a risk, and an associated outcome. This review applies several models of Mendelian randomization to large, publicly available, genetic databases of both European and Asian populations to identify genetic associations between primary open-angle glaucoma, intraocular pressure, and myopia.
Clinical Value/Implications: Researchers found a strong bidirectional genetic association between both myopia and primary open-angle glaucoma. This link appears to be primarily mediated by the even stronger link between elevation in intraocular pressure and myopia. The authors go on to speculate that this link appears strong enough that treating patients with myopia who have ocular hypertension even prior to a clear diagnosis of glaucoma may be worthwhile. Further, the fact that these relationships were found to be bidirectional at least suggests that efforts to prevent myopia genesis may have additional benefit in reducing risk of glaucoma as well, although both points were speculative and not specifically studied.
Intravitreal Therapy for Uveitic Macular Edema—Ranibizumab Versus Methotrexate Versus the Dexamethasone Implant: The MERIT Trial Results
The Multicenter Uveitis Steroid Treatment Trial Research Group
Acharya N, Vitale A, Sugar E, et al. Ophthalmology 2023;1-10
Question: Is there a difference in the comparative effectiveness of dexamethasone implant, intravitreal methotrexate, and intravitreal ranibizumab in reducing the central subfield thickness in patients with minimally active or inactive uveitis and persistent macular edema in one or both eyes after 12 weeks of treatment?
Background/Summary of Findings
Macular edema is the most common complication of uveitis and can result in loss of vision. The current treatment standard in cases with persistent uveitic macular edema is repeated intravitreal corticosteroid injections. Although these injections often result in resolution, upward of 40% of cases will relapse. The potential risks associated with repeat corticosteroid injections necessitate exploring the value of noncorticosteroid agents in uveitic macular edema management. In this study, patients with persistent macular edema, defined by a central subfield thickness of >300 μm for Zeiss cirrus or Topcon spectral domain optical coherence tomography or >320 μm for Heidelberg Spectralis, were randomized 1:1:1 to receive dexamethasone 0.7 mg implant, methotrexate 400 μg/0.1 mL, or ranibizumab 0.5 mg/0.05 mL. Retreatment schedule protocols differed based on which interventions the patients were randomized to.
After 12 weeks, all three groups demonstrated statistically significant reduction in central subfield thickness relative to baseline measurements. Dexamethasone had a greater percentage reduction in central subfield thickness than methotrexate or ranibizumab (35% vs 11% vs 22% reduction, respectively). The dexamethasone group also had a significantly greater gain in visual acuity than the other two therapies. Both the dexamethasone and ranibizumab groups had improved NEI-VFQ-25 scores; the methotrexate group did not improve. The incidence of intraocular pressure elevations to 30 mm Hg was significantly higher in the dexamethasone group than in the methotrxate or ranibzumab (10% vs. 1% and 1%, respectively). Overall ocular and systemic side effects were infrequent.
Clinical Value/Implications
Dexamethasone was superior to both ranibizumab and methotrexate, with methotrexate not achieving any clinically meaningful improvement in central subfield thickness. Although known side effects exist, intraocular corticosteroids remain the most effective way to treat persistent uveitic macular edema, when not absolutely contraindicated. Optimally, corticosteroid-sparing agents would successfully treat this condition with substantially diminished side effects; however, none have been shown to supplant steroids at this time.