SD-OCT Shows Progressive Glaucomatous Damage Undetected by Conventional Methods
Liu et al. set out to establish whether progressive loss of the retinal nerve fiber layer (RNFL) occurs in the fellow eye of patients who have unilateral glaucoma. This prospective longitudinal, observational cohort study found that a substantial proportion of fellow eyes demonstrated a significant decline in RNFL thickness over time.
The study included 175 patients (346 eyes)—118 eyes with glaucoma and 228 eyes with suspected glaucoma—who were followed for an average of 3.5 ± 0.7 years. All study participants underwent standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in both eyes at 6-month intervals. Eyes were determined to be progressing by conventional methods: either masked grading of optic disc stereophotographs or SAP Guided Progression Analysis (GPA; Carl Zeiss Meditec).
Thirty-nine participants showed evidence of unilateral progression by the conventional methods of GPA, disc photographs, or both during the follow-up period. In these patients, the mean ± standard error rate of RNFL loss in the progressing eye was –0.89 ± 0.22 μm/year (p < .001), and the fellow eye also showed significant RNFL loss (–1.00 ± 0.20 μm/year; p < .001). The remaining 134 participants did not show progression by conventional methods in either eye; however, RNFL thickness declined in these eyes as well (–0.71 ± 0.09 μm/year; p <.001).
The authors concluded that loss of RNFL thickness occurs in a significant number of eyes that do not show progression when measured by conventional methods. Further, because glaucomatous damage is irreversible, they recommend identification of progression at an early stage, before it can be seen on stereo disc photography or SAP.
CATT Trials: VA Response at Week 12 Is a Good Predictor of 2-Year Outcomes
In a secondary analysis of 1,185 participants from the Comparison of Age-Related Macular Degeneration Treatment Trials (CATT), Ying et al. examined the association between baseline characteristics and early visual acuity (VA) responses among participants with visual outcomes at years 1 and 2.
Patients with a visual acuity of 20/25 to 20/320 were randomly assigned to ranibizumab or bevacizumab and to 1 of 3 dosing regimens. The main outcome measure was change in visual acuity from baseline.
Statistically significant baseline predictors of less gain in visual acuity at year 2 were older age, VA of 20/40 or better, larger area of choroidal neovascularization, presence of geographic atrophy, total foveal thickness ≤325 µm or ≥425 µm, and elevation of retinal pigment epithelium.
The researchers concluded that VA at week 12 is more predictive of visual outcomes at 2 years than are several other baseline characteristics or the response at week 4, and that outcomes at year 1 were similar to those at year 2. They also found that some eyes with an initial decline in VA experienced late VA gains and noted that this finding supports continuation anti-VEGF therapy despite early lack of response.
HIV-Related Neuroretinal Disorder and Vision-Specific Quality of Life
Ashraf et al. found that some individuals infected with HIV have optic nerve or retinal dysfunction that presents as decreased contrast sensitivity despite good best-corrected visual acuity (BCVA). This condition, known as HIV-related neuroretinal disorder (HIV-NRD), poses a risk of visual impairment, blindness, and increased mortality. The researchers investigated the effect of HIV-NRD on vision-specific quality of life (QOL).
Study participants were drawn from the Longitudinal Study of the Ocular Complications of AIDS. Among the 2,392 participants, 813 met the study criteria. Each participant completed the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25), had a BCVA of 20/40 or better, and had no evidence of an ocular opportunistic infection or cataract. The researchers compared QOL by HIV-NRD status and adjusted for potentially confounding variables.
Of the 813 participants, 39 were found to have HIV-NRD. Compared with the participants without HIV-NRD, those with NRD had significantly lower scores on composite VFQ-25 and on 8 of the 11 subscales. The differences in QOL were independent of BCVA and markers of HIV disease severity. The researchers stated that reduced contrast sensitivity, which is characteristic of NRD, has been linked with increased falls, decreased reading speed, avoidance of driving, and other factors that affect QOL.
They concluded that even though the incidence of vision loss from opportunistic infections such as cytomegalovirus infection has decreased substantially with the wide adoption of antiretroviral therapies, ocular conditions such as NRD still have a negative effect on the QOL of HIV survivors.
HPV Infection in OSSN Tumors and the Response to Interferon
Galor et al. determined the presence and frequency of human papilloma virus (HPV) in ocular surface squamous neoplasia (OSSN). They also examined differences in the clinical features and response to interferon treatment of tumors with positive versus negative HPV results.
In this retrospective case series, 21 of 27 tumors (78%) were positive for HPV. The identified HPV genotypes included HPV-16 (10 tumors), HPV-31 (5 tumors), HPV-33 (1 tumor), HPV-35 (2 tumors), HPV-51 (2 tumors); in addition, a novel type of HPV was found in 3 tumors. Twenty tumors had only 1 genotype, while 1 tumor manifested 3 identified genotypes.
Further, tumors that were positive for HPV-16 were larger (68 mm2 vs. 34 mm2) and were more likely to have papillomatous morphologic features (50% vs. 12%) compared with tumors that were negative for HPV-16.
In conclusion, the researchers observed a high occurrence of HPV in the OSSN tumors they examined, and HPV-16 accounted for almost half of the HPV strains identified. Further, although they had originally hypothesized that presence of HPV in OSSN would enhance the response to treatment with interferon, they found no difference in response between HPV-positive and HPV-negative tumors.
Ophthalmology summaries are written by Marianne Doran and edited by Susan M. MacDonald, MD.
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