RISK FACTORS FOR RAPID GLAUCOMA DISEASE PROGRESSION

 

It is well known that some glaucoma patients tend to progress more rapidly compared to other patients, even though the diagnostic parameters in the two groups such as C:D ratio, and IOP are similar.

On visual field (VF) analysis rapidly progressive disease is defined as a decline in MD of greater than or equal to 1 dB/year. This is regarded as significant as it can lead to progression of the disease from early to advanced stage in just 10-15 years.

Usually, glaucoma patients have an average rate of progression between -0.3 and -0.5 dB decline in mean deviation (MD) per year.

Chan et al, have compared 48 rapidly progressing eyes (progression ‡1 dB mean deviation [MD]/year) with 486 non–rapidly progressing eyes (progression <1 dB MD/year).

The objective of their study was to determine the intraocular and systemic risk factor differences between a cohort of rapid glaucoma disease progressors and nonrapid disease progressors.

• The study found that rapid progressors were older, and had significantly lower central corneal thickness (CCT). These patients also had lower baseline intraocular pressure (IOP), and a significantly worse baseline MD compared with nonrapid progressors.
• The rapid progressors were more likely to have pseudoexfoliation syndrome, disc hemorrhages, changes in ocular medications, and glaucoma surgery.
• These patients had significantly higher rates of cardiovascular disease and hypotension. Subjects with cardiovascular disease were 2.33 times more likely to develop rapidly progressive glaucoma disease despite significantly lower mean and baseline IOPs.

The mean rate of progression for rapid progressors was -1.55 dB/year, while for nonrapid progressors it was -0.24 dB/year.

Average IOP and IOP fluctuation were not significantly different between rapid progressors and nonrapid progressors. Reported rates of hypertension, diabetes mellitus, migraines, vasospasm, steroid use, and high myopia were also not significantly different between the 2 groups.

 REFERENCE:

Chan TCW, Bala C, Siu A, Wan F, White A. Risk Factors for Rapid Glaucoma Disease Progression. Am J Ophthalmol. 2017 Aug;180:151-157. doi: 10.1016/j.ajo.2017.06.003. Epub 2017 Jun 15. PMID: 28624324.

 

EXERCISE IN GLAUCOMA: TO DO OR NOT TO DO?

 

DR. ALIYA

P.G. SCHOLAR

DEPT OF ILAJ-BIT-TADBEER

STATE UNANI MEDICAL COLLEGE AND HOSPITAL

PRAYAGRAJ, INDIA

 

Controversy exists among the patients and the healthcare industry about whether exercise, especially certain exercises such as yoga, is useful or harmful for glaucoma patients.

Many articles have shown the positive and negative sides of exercises on glaucoma status.

PROS OF EXERCISE:

Studies have shown that aerobic exercises are particularly useful in glaucoma patients. These exercises improve circulation in the brain and therefore, are useful for the eye, especially in glaucoma patients who have vascular anomalies contributing to glaucomatous damage.

A prominent glaucoma expert, Dr. Robert Ritch recommends 45 minutes of aerobic exercise 3-4 times per week. Walking, swimming, biking, or working out on stationary machines lowers intraocular pressure (IOP) and improves blood circulation to the eye and brain.

A study by Lee et al reported that increased walking, greater time spent doing moderate-to-vigorous physical activity, and more time spent in non-sedentary activity were associated with slower rates of VF loss in a treated population of patients with glaucoma, with an additional 5000 daily steps or 2.6 hours of non-sedentary physical activity decreasing the average rate of VF loss by approximately 10%. [1]

A study by Janicijevic et al reported that low-intensity aerobic exercise had a lowering effect on IOP, being the beneficial effect more accentuated and prolonged in the High-fit group (IOP reduction compared to baseline lasted 30 minutes) than in the Low-fit group (IOP was only reduced at 6 minutes of exercise compared to baseline). [2] 

Ramulu and associates have also found that substantial reductions in physical activity and walking were noted with greater levels of VF loss. [3] 

In experiments on mice, Chrysostomou and collegues reported that exercise almost completely reversed age-related vulnerability of the optic nerve to injury such that exercised aged mice had a similar functional response to injury as non-exercised young (3-month-old) mice. Exercise also abrogated injury-induced astrocytic gliosis and macrophage activation in the aged retina. These data suggest that the known benefits of exercise also extend to the visual system and support further investigation of physical activity as a means of protecting against injury, dysfunction, and degeneration in the aging eye. [4] 

A meta-analysis has found that mild-intensity aerobic exercises are beneficial because of their diverse mechanisms in glaucoma patients. They can help in the transient reduction of IOP and have a beneficial effect on glaucoma severity and progression. [5] 

CONS OF EXERCISE:

A large study from the UK Biobank Eye and Vision Consortium did not find a significant association between exercise and glaucoma. Higher overall physical activity (PA) level and greater time spent in moderate and vigorous exercise were not associated with glaucoma status but were associated with thicker mGCIPL. Associations with IOP were modest and inconsistent. Despite the well-documented acute reduction in IOP after PA, there was no evidence that high levels of habitual PA are associated with glaucoma status or IOP in the general population. [6] 

Certain yoga postures are especially harmful for glaucoma patients. Studies have shown downward facing dog (adho mukha svanasana), standing forward bend (uttanasana), Plow (halasana), and legs up the wall (viparita karani) are especially harmful in glaucoma patients. A study found that the above mentioned four poses raised IOP in both the control group and the glaucoma patients, with the greatest increases associated with downward-facing dog. Once the subjects returned to a seated position, they were tested immediately and 10 minutes later. The IOP returned to baseline levels at these time points.

A study by Liu et al found that arterioles show increased stiffness with aging and it cannot be reversed with exercise.[7] 

CONCLUSION:

It can be inferred from the above studies that light aerobic exercises are useful, but heavy exercises like weight-lifting and certain yoga postures are deleterious for glaucoma patients and should be avoided.

REFERENCES:

1. Moon Jeong Lee, Jiangxia Wang, David S. Friedman, Michael V. Boland, Carlos G. De Moraes, Pradeep Y. Ramulu, Greater Physical Activity Is Associated with Slower Visual Field Loss in Glaucoma. Ophthalmology, Volume 126, Issue 7,2019,Pages 958-964.
2. Janicijevic, D., Redondo, B., Jiménez, R., Garcia-Ramos, A., & Vera, J. (2022). The intraocular pressure lowering-effect of low-intensity aerobic exercise is greater in fitter individuals: a cluster analysis. Research in Sports Medicine, 32(1), 86–97.
3. Pradeep Y. Ramulu, Eugenio Maul, Chad Hochberg, Emilie S. Chan, Luigi Ferrucci, David S. Friedman, Real-World Assessment of Physical Activity in Glaucoma Using an Accelerometer, Ophthalmology, Volume 119, Issue 6, 2012, Pages 1159-1166, https://doi.org/10.1016/j.ophtha.2012.01.013.
4. Chrysostomou V, Kezic JM, Trounce IA, Crowston JG. Forced exercise protects the aged optic nerve against intraocular pressure injury. Neurobiol Aging. 2014 Jul;35(7):1722-5. doi: 10.1016/j.neurobiolaging.2014.01.019. Epub 2014 Jan 23. PMID: 24524967.
5. Gildea, David MB BCh BAO; Doyle, Aoife MB, BCh; O’Connor, Jeremy MB, BCh. The Effect of Exercise on Intraocular Pressure and Glaucoma. Journal of Glaucoma 33(6):p 381-386, June 2024. | DOI: 10.1097/IJG.0000000000002411.
6. Madjedi KM, Stuart KV, Chua SYL, Ramulu PY, Warwick A, Luben RN, Sun Z, Chia MA, Aschard H, Wiggs JL, Kang JH, Pasquale LR, Foster PJ, Khawaja AP; Modifiable Risk Factors for Glaucoma Collaboration and the UK Biobank Eye and Vision Consortium. The Association of Physical Activity with Glaucoma and Related Traits in the UK Biobank. Ophthalmology. 2023 Oct;130(10):1024-1036. doi: 10.1016/j.ophtha.2023.06.009. Epub 2023 Jun 17. PMID: 37331483; PMCID: PMC10913205.
7. Liu C, Kobayashi T, Shiba T, Hayashi N (2022) Effects of aging and exercise habits on blood flow profile of the ocular circulation. PLoS ONE 17(4): e0266684.

 

SMARTPHONE USE AND INTRAOCULAR PRESSURE

 

Smartphone and digital device use has become very common. It would be interesting to know the effect of using phones on intraocular pressure (IOP). A few studies have been performed to analyze the effect of using smartphones on IOP.

A study was performed by Srivastava et al, to compare the effect on IOP while reading smartphone digital text and printed text in healthy, and in glaucoma patients. The study included 60 healthy and 22 patients who had medically controlled POAG. The participants were asked to perform reading tasks on printed text followed by digital text on a smartphone. The IOP assessment was done at baseline and subsequently at 10, 20, and 30 minutes of reading and 10 and 20 minutes after completing the reading tasks. IOP variations from baseline were measured and compared. The mean baseline IOP in volunteers was 14.58 (±2.91) mmHg, while in POAG patients it was 15.02 (±2.18) mmHg. The IOP was found to rise in all participants (healthy, as well as, glaucoma patients) while reading both printed text and digital text. It returned to normal 20 minutes after stopping the reading. However, there was a relatively marked rise in IOP on reading smartphone text, compared to digital text.

Ha et al, performed a study on healthy volunteers to investigate the effect of reading or writing on a smartphone on IOP changes. The study included 39 healthy volunteers less than 40 years of age. The participants were tasked to conduct standardized work (i.e., read a sample text on a single mobile device and subsequently type it on the same device) under daylight [300 lux] and low-light [100 lux] conditions independently on consecutive days. On each day, three sets of IOP measurements (total: 7) were performed: (1) pre-work (baseline), (2) during smartphone work [5, 15, and 25 minutes], and (3) post-work [5 and 15 minutes].

The study reported that the mean IOP had a persistent rise from baseline under daylight conditions. While the baseline IOP was around 14 mmHg, it increased to around 15 mmHg after 5 minutes of work, then almost 16 mmHg after 15 minutes of work, and persisted over 25 minutes of smartphone use. When the smartphone use was stopped for 5 minutes, the IOP returned to levels even below baseline levels.

The underlying ocular dynamics for these IOP changes during and after smartphone work are unclear, though the following mechanisms are assumed to be involved: 1) Accommodation and convergence; 2) external ocular muscle (EOM) contraction; 3) psychophysiological stress; 4) dry eye; 5) neck-flexion posture.

Therefore, smartphone users concerned about IOP fluctuation are advised to:

1.  Take a break if they read or write on their smartphone for more than 5 minutes, 
2.  Avoid using smartphones wherever possible in dark places.

REFERENCES:

Srivastava, Rajat Mohan; Agrawal, Siddharth; Amrin, Nayani; Bharti, Devanand. Intraocular Pressure Changes While Reading Smartphone Digital Text Versus Printed Text in Healthy Individuals and those with Glaucoma. Journal of Glaucoma 33(3):p 189-194, March 2024. | DOI: 10.1097/IJG.0000000000002314

Ha A, Kim YK, Park YJ, Jeoung JW, Park KH (2018) Intraocular pressure change during reading or writing on smartphone. PLoS ONE 13 (10): e0206061.

 

FLOOR EFFECT ON OCT

 

In advanced glaucoma, OCT of the optic nerve head (ONH)/retinal nerve fiber layer (RNFL) can give rise to various errors and may not be an ideal investigation for such patients.

As glaucoma advances, RNFL measurement continues to decrease, but it doesn’t go to zero. This is known as the “floor effect.”

The “floor effect” is defined as the point at which no further structural damage can be measured.

This happens because the architectural support made up of Müller cells, astroglia, microglia, and blood vessels doesn’t degenerate completely with retinal ganglion cell axons.

This floor effect, possibly due to the presence of residual tissue (e.g., glial cells, blood vessels) or failure of tissue segmentation algorithms (i.e., an artefactual floor), is thought to be a serious problem for monitoring structural changes in eyes with advanced glaucoma.

Even though the patient with advanced disease may be progressing, it is often challenging to detect any observable change with optical imaging. In these eyes, monitoring of disease must rely on standard automated perimetry (SAP) or other visual function tests. Although SAP is a standard clinical test, SAP measurements of visual sensitivity are notoriously variable, particularly as glaucoma severity increases.

This patient was observed to have 0.9 C:D R in both eyes on slit-lamp examination. However, the OCT shows 0.9 in the left eye only and 0.56 in the right eye. This is likely from the floor effect, as the scan is eccentric and not assessing the floor of the cup.

FURTHER INFO:

https://www.aao.org/eyenet/article/estimating-oct-structural-measurement-floors-to-de#:~:text=In%20retinal%20imaging%2C%20the%20%E2%80%9Cfloor,floor%20in%20patients%20with%20glaucoma.

FYSX: ocular pressure adjusting pump

 

FYSX (pronounced as physics) is an intraocular pressure (IOP) adjusting pump, developed by Balance Ophthalmics.

The device has received FDA’s DeNovo classification, which denotes a “risk-based classification process” to provide a marketing pathway to classify novel medical devices that “provide reasonable assurance of safety and effectiveness for the intended use.”

FYSX is a first-of-its-kind device that provides a nonpharmacological, nonsurgical treatment modality to reduce IOP.

The device is particularly useful for patients with primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG).

The device features a portable pump attached to pressure-sensing goggles that are worn at night when IOP typically increases. Separate tubes are attached to each eyepiece to create/monitor negative pressure.

The programmable pressure-modulating pump is compact and portable. It incorporates two diaphragm pumps to create negative pressure in each eye. Each pump exerts up to -40 mmHg relative atmospheric pressure. The goggles and the pump are connected mechanically and pneumatically through a tubing system.

The device reduces IOP so long as it working and the effect apparently tapers off once the pump shuts down.

The most frequently reported ocular adverse events with the use of FSYX are:

• Eyelid edema (11.8%)
• Dry eye signs and symptoms (5.4%)
• Conjunctival hyperemia (4.3%)
• Eye pain (3.2%)
• Eyelid erythema (2.2%)

ONLINE CIRCULAR CONTRAST PERIMETRY (OCCP)

 

Online Circular Contrast Perimetry (OCCP) is a web-based computer application. The method allows patients to undergo routine perimetry from the comfort of their homes via a personal computer or tablet.

The method has several advantages, such as, improved access to perimetry, the option of home perimetry, significant cost saving benefits in perimetric hardware for clinicians, cheaper healthcare delivery for healthcare funders, a more enjoyable user experience for patients, ease of sharing data between clinics for collaborative care, and data integration within electronic medical records.

Studies comparing OCCP to SAP have shown favorable results regarding similar perimetric outcomes, similar diagnostic accuracy, and an improved user experience. A pilot study has demonstrated the benefit of the personal computer-based OCCP test to distinguish glaucoma from normal eyes with sensitivity 92% and specificity 87%

The OCCP test is built on a python-based web application and hosted on Azure (Microsoft, Redmond US), with tailored database integrity and high-security architecture.

A study to assess the effectiveness of OCCP used computers with screen size 24-inches diagonally (white temperature at 6500K, gamma set at 2.2 and resolution of 1920 × 1080 pixels).

The test was performed in a dark room with lighting solely from the computer monitor, minimal background noise, and computers turned on 15 minutes prior to OCCP testing to ensure consistency of screen brightness and adaptation.

OCCP utilizes flickering circular targets to assess visual sensitivity. These targets are similar to those in Pulsar perimetry (Haag-Streit International, Bern, Switzerland) with the same level of contrast in all radial directions, to avoid stimulation of those cells that selectively respond to a given orientation, but differ from Pulsar spots by being smaller in size and of consistent contrast throughout the spatial extent of the target despite a thin rim of contrast reduction at the peripheral target edge.

Targets consist of concentric sinusoidal contrast rings. The bright peaks have the same luminance as the background monitor, while the dark troughs determine the difficulty level of the target. On flicker, these targets alternate with their inverse image (with dark troughs replacing bright peaks, and vice versa).

Targets are present for 360 milliseconds with three counterphase flicker cycles each lasting 60 milliseconds and utilize sinusoidal contrast with spatial frequency 0.5 cycles/degree and temporal counter phase flickering at 9 hertz.

The contrast is ramped up and down at the beginning and end of target presentations respectively.

A continuously spinning golden star (3.5 degrees of visual angle) is used as a fixation target, located at the screen center throughout the test.

The study found mean sensitivity per loci of central 10-degree OCCP similar to traditional perimetry when mapped against SAP including adherence to a physiological hill of vision.

OCCP sensitivity reduces with eccentricity more than SAP, which implies that a magnification correction factor will be useful to provide consistent normal sensitivities at each locus.

On average, the OCCP test duration is 1:20 (minutes: seconds) longer than SAP.

REFERENCES:

Skalicky, S.E., Bigirimana, D. & Busija, L. Online circular contrast perimetry via a web-application: optimising parameters and establishing a normative database. Eye 37, 1184–1190 (2023). https://doi.org/10.1038/s41433-022-02085-4.

Meyerov J, Deng Y, Busija L, Bigirimana D, Skalicky SE. Online Circular Contrast Perimetry: A Comparison to Standard Automated Perimetry. Asia Pac J Ophthalmol (Phila). 2023 Jan-Feb 01;12(1):4-15. doi: 10.1097/APO.0000000000000589. Epub 2023 Jan 2. PMID: 36706329.

EFFECT OF MASSAGE ON IOP

 

DR. SHIBRA FAROOQ

P.G. SCHOLAR

DEPARTMENT OF ILAJ-BIT-TADBEER

AJMAL KHAN TIBBIYA COLLEGE,

ALIGARH MUSLIM UNIVERSITY, INDIA

 

Intraocular pressure (IOP) fluctuates with body position. The IOP is lowest in the sitting posture and increases in the order of supine and lateral decubitus positions.

These changes are attributed to the increase in episcleral venous pressure and choroidal vascular volume. The uveal tissues also develop congestion and expansion from increased venous and arterial pressures in the orbit, contributing to the increased IOP.

Massage is an important component of Ilaj-bit-tadbeer in Unani medicine. Known as dalk, it is done for both prophylactic and therapeutic reasons.

Body massage has also become popular recently as a relaxation technique. Massage parlors and spas are coming up in different places.

In a study from Thailand, participants received muscle relaxing massage and facial lymphatic drainage for 15 minutes. The mean IOP significantly decreased 0.87+1.43 mmHg (p=0.01) for the right eyes. However, no significant difference in the left eyes was seen. [1]

Therefore, massage to relax muscles and lymphatic drainage of muscles around the head and face might reduce IOP.

In a study from the Philippines, 46 volunteers were recruited to have a back massage in the prone position for 30 minutes by a professional masseuse. The IOP was taken before the massage, and after the massage. The IOP uniformly increased in 43 of the 46 participants immediately after the massage. [2]

A study was performed by Patel et al, at Temple University, USA to determine the effect of foot reflexology in primary open-angle glaucoma (POAG) and ocular hypertension (OHT). Patients with glaucoma performed a 5-minute foot massage on a foot massage board. In the POAG patients, the IOP significantly decreased up to 10% of the pre-massage levels. [3]

These studies show that IOP changes with body posture and patients with glaucoma can be informed of the risks of lying in the same posture for long periods. The risk of supine position is greatest and individuals with glaucoma or those at risk of glaucoma should not undergo such massages.

On the contrary, facial massage, and foot massage reduce IOP and can probably be taught to individuals to perform themselves at home.

REFERENCES:

1. Pattaranit, P., Ratanapakorn, T., Limphatcharaporn , J., & Sitthiracha , P. (2022). Immediate Effect of Facial Massage and Lymphatic Drainage Massage on Intraocular Pressure. Journal of Vongchavalitkul University, 35(1), 45–59. Retrieved from https://ph01.tci-thaijo.org/index.php/vujournal/article/view/245503.
2. https://paojournal.com/article/the-effect-of-body-massage-lying-face-down-on-intraocular-pressure-in-normal-eyes/. Last accessed on 07.07.2024
3. Patel D, Henderer JD, Kung P, Cohen D, Krane A, Yu D. The effect of foot reflexology on intraocular pressure in ocular hypertension and primary open-angle glaucoma patients. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2563.

ROLE OF OMEGA-3 IN GLAUCOMA

 

DR. SADAF JAHAN

P.G. SCHOLAR

Department of Amraz Ain, Uzn, Anf, Halaq wa Asnan,

State Unani Medical College and Hospital

Prayagraj, India

Some studies have shown that glaucoma patients have low omega-3 essential fatty acid (EFA) blood levels, especially docosahexaenoic acid and eicosapentaenoic acid (EPA). It is known that the ratio of consumed omega-3 to omega-6 EFAs determines the body's inflammatory status. The omega-3s promote prostaglandin metabolism leading to the production of eicosanoids which are anti-inflammatory in nature. Therefore, omega-3 EFA deprivation may predispose individuals to ocular disease.

The role of omega-3 in glaucoma is not yet clear. The agent is an antioxidant and has some role in diseases such as dry eyes. However, there are very few studies to confirm if omega-3 would be beneficial in glaucoma patients.

Glaucoma patients have lower omega-3 fatty acid blood levels, especially docosahexaenoic acid (DHA) and EPA. Ye and colleagues have shown that dietary omega-3 supplementation in patients may normalize levels of fatty acid and enhance their effects. The study reported that active ingredients in fish oil delay glaucoma development, lower IOP, regulate blood supply, alleviate inflammation, and diminish oxidative stress. These effects can have a positive response in glaucoma patients. [1]

Data from the National Health and Nutrition Examination Survey (NHANES, 2005–2008), a cross-sectional survey involving 3865 participants from the United States, showed that increased daily consumption of the long-chain, polyunsaturated omega-3 fatty acids, EPA, and DHA, was associated with a lower likelihood of glaucomatous optic neuropathy. [2]

Experimental studies by Nguyen et al, have found that omega-3 EFAs decrease IOP in rats. [3]

Pooled analysis of data from two double-masked, placebo-controlled randomized trials (Australian New Zealand Clinical Trials Registry, ACTRN12614001019695, ACTRN12615000173594) investigated the efficacy and safety of oral omega-3 supplementation. The analysis found that oral omega-3 supplementation for 3 months significantly reduced IOP in normotensive adults. [4]

Looking at the lack of robust studies concerning glaucoma parameters such as visual fields, it is still not clear if omega-3 supplementation will benefit glaucoma patients.

REFERENCES:

1. Ye H, Liu Y, Xu Z, Wei X. Fish Oil in Glaucoma Treatment: From Biological Functions to Clinical Potential. Mol Nutr Food Res. 2023 Jun;67(11):e2200727. doi: 10.1002/mnfr.202200727. Epub 2023 Apr 25. PMID: 37029593.
2. Wang YE, Tseng VL, Yu F, Caprioli J, Coleman A. Association of dietary fatty acid intake with glaucoma in the United States. JAMA Ophthalmol. 2017; 136: 141– 147
3. Nguyen CT, Bui BV, Sinclair AJ, Vingrys AJ. Dietary omega 3 fatty acids decrease intraocular pressure with age by increasing aqueous outflow. Invest Ophthalmol Vis Sci. 2007; 48: 756– 762.
4. Downie LE, Vingrys AJ. Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults. Transl Vis Sci Technol. 2018 May 1;7(3):1. doi: 10.1167/tvst.7.3.1. PMID: 29736322; PMCID: PMC5931260.

 

MELBOURNE RAPID FIELDS (MRF) TEST

 

The Melbourne Rapid Fields (MRF) Visual Field Test is a computer or tablet-based software. It was developed by researchers in Australia and allows testing on Apple iPads (generation 3/4 or later) and computers/laptops via Cloud technology. The software enables in-office or remote visual field testing due to its low cost and easy portability.

https://www.appviewmrf.com/what-is-mrf-visual-field-test/

The software is robust despite variations in ambient light, blur, and viewing distance. The instrument is cheaper, easier to handle, avoids the claustrophobia of bowl perimeters, and is easier to understand by patients, compared to the Humphrey Visual Field Analyzer (HFA).

A few studies have shown that the MRF software gives visual field (VF) results comparable to the HFA.

A study by Kumar and Thulasidas has shown the perimetric outcomes of MRF were comparable to those from the HFA 24-2 SITA standard. The study involved 28 eyes of 28 glaucoma patients. Mean (standard deviation) test times were 342.07 (56.70) seconds for MRF and 375.11 (88.95) for HFA 24-2 SITA standard (P = 0.046). Mean MD was significantly lower for MRF (Δ = 3.09, P < 0.001), and mean PSD was significantly higher for MRF (Δ = 1.40, P < 0.005) compared with HFA. The mean foveal threshold for the MRF was significantly lower than the mean HFA foveal threshold ((Δ = 9.25, P < 0.001). Other perimetric outcomes showed no significant differences between both methods.

Kang et al, have performed a study involving 79 participants (133 eyes) comparing MRF and HFA. Their study reported the global indices of MD and PSD did not significantly vary between HFA and the MRF techniques. However, the sensitivities significantly differed from those of the HFA at 36 and 39 locations, respectively, out of 52 locations. Relative to HFA, the tablet overestimated light sensitivity in the nasal field while underestimating the temporal field.

Kumar’s study found MRF showed a significantly lesser number of points depressed at P < 5% on PSD probability plot than HFA, pointing towards the possibility of underestimating glaucomatous defects and missing early cases of glaucoma. There is also a lack of standardized background illumination involving the tablets, compared to the standard methodology for HFA universally.

The development of an effective tracking system for monitoring head and eye positions in real-time using the iPad camera may allow fixation monitoring during peripheral field testing as well as for the central test. The poor availability of the internet and speed limitations may hamper the use of this portable method in rural and underdeveloped areas. Therefore, an internet-independent mechanism can be developed for this software.

REFERENCES:

Kumar H, Thulasidas M. Comparison of Perimetric Outcomes from Melbourne Rapid Fields Tablet Perimeter Software and Humphrey Field Analyzer in Glaucoma Patients. J Ophthalmol. 2020 Aug 22;2020:8384509. doi: 10.1155/2020/8384509. PMID: 32908686; PMCID: PMC7463344.

Kang J, De Arrigunaga S, Freeman SE, Zhao Y, Lin M, Liebman DL, Roldan AM, Kim JA, Chang DS, Friedman DS, Elze T. Comparison of Perimetric Outcomes from a Tablet Perimeter, Smart Visual Function Analyzer, and Humphrey Field Analyzer. Ophthalmol Glaucoma. 2023 Sep-Oct;6(5):509-520.